Regulatory Guide 8.36
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| Issue date: | 07/31/1992 |
| From: | Office of Nuclear Regulatory Research |
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| RG-8.36 | |
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U.S. NUCLEAR REGULATORY COMMISSION July 1992 REGULATORY (3UIDE
OFFICE OF NUCLEAR REGULATORY RESEARCH
REGULATORY GUIDE 8.36 (Draft was issued as DG-8011)
RADIATION DOSE TO THE EMBRYO/FETUS
A. INTRODUCTION
B. DISCUSSION
Calculating the radiation dose to the embryo/fe Section 20.1208 of 10 CFR Part 20, "Standards tus from internally deposited radionuclides requires for Protection Against Radiation," requires that each quantitative information about maternal radionuclide licensee ensure that the dose to an embryo/fetus dur intake, placental transfer and kinetics, and resulting ing the entire pregnancy, from occupational exposure embryo/fetus radionuclide concentrations. Intakes of of a declared pregnant woman, does not exceed 0.5 radioactive material occurring prior to the pregnancy rem (5 mSv). Paragraph 20.1208(b) requires the li may also be important if these materials remain in the censee to make efforts to avoid substantial variation pregnant woman during all or part of the gestation above a uniform monthly exposure rate to a declared period. Transfer kinetics from the mother to the em pregnant woman that would satisfy the 0.5 rem (5 bryo/fetus are modeled as a function of stage of preg mSv) limit. The dose to the embryo/fetus is to be the nancy, route of intake by the pregnant woman, and sum of (1) the deep-dose equivalent to the declared time after intake. The stage of gestation (or fetal de pregnant woman (10 CFR 20.1208(c)(1)) and (2)
velopment) is an important parameter in estimating he dose to the embryo/fetus from radionuclides in radionuclide concentrations in the embryo/fetus. The ne embryo/fetus and radionuclides in the declared geometry of the embryo/fetus (i.e., size and weight)
pregnant woman (10 CFR 20.1208(c)(2)).
affects the radionuclide dosimetry.
This guide is being developed to provide guidance It is recognized that calculation of prenatal radia on calculating the radiation dose to the embryo/fetus. tion doses from internally deposited radionuclides has Regulatory Guide 8.13, "Instruction Concerning Pre many associated difficulties, including a lack of quan natal Radiation Exposure," provides instructions con titative information about prenatal radionuclide con cerning the risks associated with prenatal radiation centrations and transfer across the placenta. The In exposure. ternational Commission on Radiological Protection (ICRP) in Publication 56 (Ref. 1) states that, for most radionuclides, preliminary estimates from dosimetric Any information collection activities mentioned and biokinetic models indicate that the dose to the in this regulatory guide are contained as requirements embryo can be approximated by the dose to the in 10 CFR Part 20, which provides the regulatory ba uterus. The dose to the fetus is dependent upon the sis for this guide. The information collection require activity present in both fetal and maternal tissues.
ments in 10 CFR Part 20 have been cleared under ICRP Publication 56 (Ref. 1) also states that, for most OMB Clearance No. 3150-0014. radionuclides, the dose to fetal tissue will be similar to USNRC REGULATORY GUIDES The guides are issued In the following ten broad divisions:
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8. Occupational Health
4. Environmental and Siting 9. Antitrust and Financial Review solutions different from those set out in the guides will be acceptable If 5. Materials and Plant Protection 10. General they provide a basis for the findings requisite to the issuance or continu ance of a permit or license by the Commission.
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similar to or less than the dose to the corresponding A graded approach for determining when to maternal tissues. evaluate, with both a simple and more detailed dose assessment methodology, is provided. Both methods The current methods available for assessing the are acceptable for evaluating the dose to the embryo/
radiation dose to the human embryo/fetus from inter fetus. It is recognized that some licensees will only nally deposited radioactive materials in the pregnant need to demonstrate that the dose to the embryo/fe woman are subject to a number of uncertainties. tus is not likely to exceed the 0.05 rem (0.5 mSv)
Revison 1 to NUREG/CR-5631, "Contribution of monitoring threshold of 10 CFR 20.1502, while other Maternal Radionuclide Burdens to Prenatal Radiation licensees may need to determine an embryo/fetus Doses-Interim Recommendations" (Ref. 2), pro dose for demonstrating compliance with the dose limit vides recommendations and methods for estimating of 10 CFR 20.1208 and the recordkeeping require the radiation doses to the embryo/fetus from internal ments of 10 CFR 20.2106(e).
radionuclides. In Revision 1 to NUREG/CR-5631, a Appendix A provides information on and a table number of radionuclides were evaluated. To expedite of dose equivalent factors for use in approximating efforts, the initial evaluation was directed to those the embryo/fetus dose from radionuclides in maternal radionuclides that were expected to be of greatest sig blood. Appendix B is a table of blood uptake frac nificance for prenatal exposure in the work environ tions for ingested activity. Appendix C contains tables ment. The radionuclides that were identified and in of gestation-time dependent doses to the embryo/fe cluded were 3H, 14C, 57Co, 58Co, 6OCo, 8 9Sr, 90Sr,
106 Ru, 1251, 1311, 1321, 133I, 1341, 1351, 134 CS, 137CS, tus following introduction of specified radionuclides
2 3 U, M4U, 23U, 238U, 23 8Pu, 239Pu, and 24 1Am. The and chemical forms into maternal blood. Examples of the use of dose assessment methods are provided in methods of Revision 1 to NUREG/CR-5631 are con Appendix D.
sidered interim as efforts continue to further develop the bases and calculational methods for estimating The total radiation dose to the embryo/fetus is prenatal radiation doses. Revision 1 to NUREG/ the sum of the deep-dose equivalent to the declared CR-5631 provides details of the data and bases for pregnant worker and the dose to the embryo/fetus the dosimetric features that were used for the radi from intakes of the declared pregnant worker. If mul onuclides listed above. tiple dosimetric devices are used to measure the deep-dose equivalent to the declared pregnant It is expected that the embryo/fetus dose assess worker, the results of monitoring that are most repre ment methods will evolve over the next several years sentative of the deep dose to the embryo/fetus may be as more research is conducted in this area. As addi used. The licensee need not use the deep dose to the tional research is conducted, better estimates of ac maximally exposed portion of the whole body of the tual embryo/fetus doses resulting from the exposure mother as the deep dose to the embryo/fetus. The of the declared pregnant woman will be possible. For licensee may employ temporary or permanent shield internal doses, research that categorizes the degree of ing to reduce the deep dose to the embryo/fetus. Al placental transfer, the resulting embryo/fetus/placenta ternatively, deep dose to the embryo/fetus may be concentrations, and the potential radiation exposures limited by placing more stringent restrictions on the of the embryo/fetus from radionuclides in their more exposure of the declared pregnant woman than on usual chemical forms should simplify assessment of other members of the occupational work force.
the dose to the embryo/fetus based on the maternal As specified in 10 CFR 20.1208(a), the dose to exposure. The ICRP is considering the formulation of the embryo/fetus from occupational exposure of the dose assessment methods specific for the embryo/ declared pregnant woman during the entire gestation fetus. period is not to exceed 0.5 rem (5 mSv). In addition, the licensee is required to make efforts to avoid sub This regulatory guide provides acceptable meth stantial variation in the monthly exposure throughout ods that may be used in determining the dose to the the period of gestation. If the dose to the embryo/fe embryo/fetus. For internal exposure, a simplified ap tus is found to have exceeded 0.5 rem (5 mSv) or is proach and a more detailed methodology are pre within 0.05 rem (0.5 mSv) of this dose by the time sented for conducting dose evaluations. The regula the woman declares the pregnancy to the licensee, tory position specified in Section 1 provides guidance the licensee is required to limit the additional dose to on the threshold criteria for use in determining when the embryo/fetus to 0.05 rem (0.5 mSv) during the the dose to the embryo/fetus needs to be evaluated. remainder of the pregnancy.
The regulatory position specified in Section 2 presents The tables in the appendices to this guide were a simplified approach for estimating the dose to the prepared directly from the computer outputs, which embryo/fetus from intakes by the declared pregnant led to the values generally being expressed to three woman. The regulatory position specified in Section 3 significant figures. This indicates greater accuracy provides an alternative, more detailed methodology than is warranted by the dosimetry model, but the for a limited number of radionuclides, using the gesta results are presented in this form to avoid roundoff tion-time dependent dosimetric data from Revision 1 errors in calculations. In general, final results should to NUREG/CR-5631 (Ref. 2). be rounded to the nearest thousandth of a rem.
8.36-2
C. REGULATORY POSITION
1.3 External Dose to the Embryo/Fetus According to 10 CFR 20.1208(c)(1), the deep CRITERIA FOR DETERMINING DOSE TO
dose equivalent to the declared pregnant woman will THE EMBRYO/FETUS
be taken as the external dose component to the em bryo/fetus. The determination of external dose
1.1 Monitoring should consider all occupational exposures of the de clared pregnant woman since the estimated date of The dose equivalent to the embryo/fetus should conception. The deep-dose equivalent that should be be determined based on the monitoring of the de assigned is that dose that would be most representa clared pregnant woman as required by 10 CFR tive of the exposure of the embryo/fetus (i.e., in the
20.1502. Specifically, 10 CFR 20.1502(a)(2) re mother's lower torso region). If multiple measure quires monitoring the exposure of a declared preg ments have been made, assignment of the highest nant woman when the dose to the embryo/fetus is deep-dose equivalent for the declared pregnant likely to exceed, in 1 year, a dose from external woman to the embryo/fetus is not required unless that sources in excess of 10% of the limit of 10 CFR dose is also the most representative deep-dose equiva
20.1208 (i.e., 0.05 rem). According to 10 CFR lent for the region of the embryo/fetus.
20.1502(b)(2), the licensee must monitor the occu pational intakes of radioactive material for the de 1.4 Internal Dose to the Embryo/Fetus clared pregnant woman if her intake is likely to ex ceed, in 1 year, a committed effective dose equivalent The internal dose to the embryo/fetus should in excess of 0.05 rem (0.5 mSv). Based on this 0.05 consider the exposure to the embryo/fetus from radi rem (0.5 mSv) threshold, the dose to the embryo/fe onuclides in the declared pregnant woman and in the tus should be determined if the intake is likely to ex embryo/fetus. The dose to the embryo/fetus should ceed 1% of ALI (stochastic) during the entire period include the contribution from any radionuclides in of gestation. the declared pregnant woman (body burden) from occupational intakes occurring prior to conception.
These monitoring thresholds will ensure that any The intake for the declared pregnant woman should potentially significant exposures to the embryo/fetus be determined using air sample data, bioassay data, are evaluated and, as appropriate, doses are deter or a combination of the tw
o. Guidance on bioassay
,ined. The conditions specified in 10 CFR measurements used to quantify intake is being devel
.1502(a) and (b) are based on a 1-yeir period. oped and has been issued for public comment as n-rior to declaration of pregnancy, the woman may Draft Regulatory Guide DG-8009, "Interpretation of not have been subject to monitoring based on condi Bioassay Measurements." Specific guidance on tions specified in 10 CFR 20.1502(a) (1) and 10 CFR workplace air sampling is in Revision 1 to Regulatory
20.1502(b)(1). In this case, the licensee should esti Guide 8.25, "Air Sampling in the Workplace."
mate the exposure during the period monitoring was not provided, using any combination of surveys or 1.5 Evaluating Continuous Exposure other available data (for example, air monitoring, For continuous or near-continuous exposure to area monitoring, bioassay). radioactive material that may be inhaled or ingested, the cumulative intake should be quantified and the The monitoring criteria contained in 10 CFR dose determined at least every 30 day
s. If significant
20.1502 do not establish required levels of detection variation in the exposure levels may have occurred, sensitivity. For some radionuclides it may not be fea the time interval for quantifying the intake should be sible to actually confirm by bioassay measurements an reduced. More frequent evaluations should be con intake of 1% of their stochastic ALI. Workplace sidered as the potential dose to the embryo/fetus ap monitoring, occupancy factors, and access control proaches the limit.
should be considered as appropriate in evaluating po tential exposures and monitoring requirements. 1.6 Existing Maternal Body Burdens Maternal body burdens resulting from internal
1.2 Evaluation of Dose to the Embryo/Fetus occupational exposures prior to conception should be included in determining the embryo/fetus dose. The The appropriate dose to be evaluated for the em contribution to the embryo/fetus dose from a mater bryo/fetus is the dose equivalent for the duration of nal burden existing at the time of conception should the pregnancy. An assessment of the 50-year commit be evaluated if the maternal burden at the time of ted dose is not appropriate. Also, it is not appropriate pregnancy exceeds 1% of the radionuclide's stochas to use effective dose equivalent or committed effec tic ALI value for the appropriate mode of intake and
"A:e dose equivalent. (Note: the committed dose class (for inhalation intakes). For multiple radio
.iivalent to the uterus may be applied to the nuclide burdens, the dose should be evaluated if the
-. nbryo/fetus under certain conditions as a simplified sum of the quotients of each burden divided by its approach as described in the regulatory position stochastic ALI exceeds 0.01. Only body burdens ex specified in Section 2.) isting at the time of conception need to be considered
8.36-3
in evaluating this threshold; radioactive material al cantly different from a 9-month gestation dose ready eliminated from the body should not be in equivalent to the embryo/fetus. Several radionuclides cluded. of this type have been evaluated in Revision 1 to NUREG/CR-5631 (Ref. 2), and data have been de This threshold of 1% ALl provides a simplified approach for determining when pre-existing body veloped for calculating an embryo/fetus gestation burdens should be evaluated. At this threshold, it is dose instead of using the committed dose equivalent to the uterus.
unlikely that any resultant dose to the embryo/fetus would be significant (i.e., greater than 10% of the 0.5 For demonstrating compliance with the dose lim rem (5 mSv) limit). As an alternative, the dose as its of 10 CFR 20.1208, the dose factors in Appendix sessment methods presented in the regulatory position *A may be used for approximating the embryo/fetus specified in Section 3 of this guide may be used for dose equivalent for the entire gestation period.
determining whether a pre-existing body burden rep resents a potentially significant dose (i.e., greater The steps for determining the embryo/fetus dose, than 0.05 rem (0.5 mSv)). using the simplified method, are as follows:
2. SIMPLIFIED METHOD FOR 2.1 Include all the intakes by the declared preg DETERMINING EMBRYO/FETUS nant woman at any time during the gestation period in DOSE FROM MATERNAL INTAKES the calculation of the embryo/fetus dose.
The determination of the dose to the embryo/fe 2.2 For ingested radionuclides, determine the tus from the intake of radioactive material by the activity uptake by the first transfer compartment pregnant woman should be based on the best avail (blood) by multiplying the intake (1) by the appropri able scientific data. At present, the NRC staff consid ate uptake factor (fl) from Appendix B (adapted ers Revision 1 to NUREG/CR-5631 (Ref. 2) to pro from Federal Guidance Report No. 11, Table 3 (Ref.
vide such data. For most radionuclides, the dose to 4)). The uptake factor, fl, is the fraction of an in the embryo/fetus will be similar to or less than the gested compound of a radionuclide that is transferred dose to the maternal uterus (Ref. 1). However, the into the first transfer compartment (i.e., blood uptake data in Revision I to NUREG/CR-5631 indicate that fraction).
for some radionuclides the embryo/fetus dose may be significantly different, either greater than or less than 2.3 For inhaled radionuclides, determining the the dose to the uterus. fraction of initial intake that is transferred to the blood involves an evaluation of the deposition in the Based on these premises (uterus dose similar to three compartments of the lung and the subsequent fetal dose and the data in Revision 1 to NUREG/ time-dependent transfer to the body fluids and to the CR-5631 (Ref. 2)), a set of dose factors has been GI tract. Unless it is known otherwise, it should be developed for use in calculating an embryo/fetus assumed that the transfer from the lung to body fluids dose. Except for those radionuclides addressed in and from lung to GI tract to body fluids follows the Revision 1 to NUREG/CR-5631 (Ref. 2), the dose ICRP 30 (Ref. 3) modeling (which is the basis for this factors presented in Appendix A to this guide repre guide).
sent the committed dose equivalent to the uterus per introduction of unit activity into the first transfer 2.4 For simplicity and conservatism in the mod compartment (i.e., blood) of the woman.' For the eling, the total uptake into the blood from the mater radionuclides in Revision 1 to NUREG/CR-5631, the nal intake is assumed to be instantaneous. However, dose factors in Appendix A represent the maximum for radionuclides with lung clearance class of W (10
dose equivalent to the embryo/fetus for the gestation to 100-day half-life clearance) or Y (greater than period from the introduction of unit activity into the 100-day half-life clearance), the actual translocation first transfer compartment of the woman at any time from the lung and uptake in the blood may occur during the gestation period. over a time period that exceeds the gestation period.
Clearance from the lung may take up to several years.
The dose limit for the embryo/fetus is expressed All the initially deposited material is not immediately as a 9-month gestation dose equivalent. Particularly available for uptake by the first transfer compartment for certain radionuclides with both long radiological (blood). However, an incremental transfer from the half-lives and long-term biological retention, the com lung to the blood may be assessed based on the lung mitted dose equivalent to the uterus may be signifi model as described in ICRP Publications 30 and 19 (Refs. 3 and 5).2
'The committed dose equivalent factors for the uterus pre sented in Appendix A were calculated based on the modeling Table 1, adapted from the data in Figure 5.2 of employed during the development of the ICRP 30 (Ref. 3) ICRP 30 (Ref. 3), may be used for determining the data. It is recognized that the metabolism of the pregnant woman may not be adequately represented by the standard total transfer from the lung to the first transfer metabolic model. However, partly because of the lack of 2As modeled in ICRP Publications 19 and 30, the clearance more definitive data, this modeling has been used for deter from the different lung compartments is assumed to follow mining the dose commitment factors for the uterus that may first-order kinetics. This approach is complex, involving in be used for evaluating compliance with the embryo/fetus terlinking differential equations, and is considered outside the dose limit. scope of a routine operational health physics program.
8.36-4
compartment (i.e., blood), where f, is the blood up take fraction from Appendix B.3 The lung clearance inhaled activity of radionuclide i that enters class (D, W, or Y) for a particular chemical form of a the blood, see Table 1 of this guide)
)articular radionuclide may be obtained from Appen 2.6 For pre-existing body burdens, the total bur dix B to 10 CFR 20.1001-20.2401. den determined to exist at time of pregnancy should be assumed to be available for uptake in the blood of Table 1 the woman. The dose should be assigned to the em Transfer Fraction of Inhaled Activity bryo/fetus as if the maternal blood uptake occurs to First Transfer Compartment within the first month of pregnancy. The embryo/fe tus dose is calculated by multiplying the maternal bur Class Transfer Fraction (TF) den of the radionuclide by its dose factor from Ap pendix A using the equation:
D 0.48 + 0.15 f, DE = AiAxDFi (Equation 3)
W 0.12 + 0.51 f, where:
Y 0.05 + 0.58 f, DE = dose equivalent to the embryo/fetus Al = maternal burden existing at time of preg
2.5 Based on the determination of the maternal nancy (ACi)
intake, the dose to the embryo/fetus for the entire DFi = dose conversion factor (Appendix A)
gestation period should be calculated using the follow ing equations: This method provides a simplified and conserva tive approach for evaluating the significance of pre For ingestion intakes:
existing conditions. If the embryo/fetus is likely to re DE = I1ixf 1 ,ixDFi ceive a dose in excess of 25% of the limit from pre (Equation 1)
existing burdens (i.e., greater than 0.125 rem (1.25 For inhalation intakes: mSv)),4 more detailed modeling should be consid ered.
DE = 2 Ii x TFi x DFj (Equation 2)
2.7 Doses from multiple nuclides or multiple in here: takes should be evaluated on a frequency correspond ing to the determination of the intake. Multiple dose DE = dose equivalent to the embryo/fetus for the determinations should be added to determine the to entire gestation period from the acute intakes tal dose. Doses may need to be reevaluated if better of all radionuclides during the gestation estimates of intakes are provided by followup bioassay period (rem) measurements.
= intake of radionuclide i by the declared preg 3. DETERMINING GESTATION-TIME
nant woman at any time during the gestation DEPENDENT DOSE TO THE
period (gCi) EMBRYO/FETUS USING REVISION 1 TO
DFi = dose factor for use in approximating the dose NUREG/CR-5631 METHODS
equivalent to the embryo/fetus for the entire gestation period from the introduction of unit As an alternative to the simplified methods pre activity (1 jiCi) into the, 'maternal blood at sented above, a gestation-time dependent dose to the any time during the gestation period, from embryo/fetus may be calculated for the radionuclides tabular data presented in Appendix A to this addressed in Revision I to NUREG/CR-5631 (Ref.
guide (rem/RCi in maternal blood) 2). Revision 1 to NUREG/CR-5631 presents dosimetric methods for calculating the dose to the fl, = the fraction of radionuclide i reaching the body fluids following ingestion (i.e., the frac 4 This approach for evaluating pre-existing body burdens does tion of ingested activity of radionuclide i that not specifically address time-dependent releases as could oc enters the blood), from data presented in cur for certain radionuclides with both a long biological reten tion and radiological half-life. However, the assumption of Appendix B to this guide blood uptake of the total burden in the first month of the ges tation period provides a simple method with reasonable assur TFi = transfer fraction of inhaled activity to the first ance that any actual dose to the embryo/fetus will not be sig transfer compartment (i.e., the fraction of nificantly underestimated. More detailed evaluations may be needed for unusual circumstances in which a pre-existing body burden could present a significant source of exposure to the embryo/fetus. An evaluation of this nature should be con
3 The coefficients for the transfer fraction equations in Table 1 ducted by individuals knowledgeable in the area of internal re applicable to particles with a 1-micrometer activity me dosimetry. Such a detailed evaluation could consider the ele Jan aerodynamic diameter (AMAD). As a default, these ment retention functions as presented in ICRP Publications 30
equations may be used for all particle sizes. However, if the and 54 (Refs. 3 and 6). Also, the modeling presented in actual particle size distribution is known, transfer fractions Revision 1 to NUlREG/CR-5631 (Ref. 2) could be applied.
for other AMAD particle sizes may be derived from data in The details of this type of an evaluation are beyond the types Figure 5.2 of ICRP 30 (Ref. 3). of analyses that are considered routinely required and, as such, are outside the scope of this guide.
8.36-5
embryo/fetus following the instantaneous introduction the days-to-date in the first gestation month at time of of unit activity into the first transfer compartment intake divided by 30 days. For example, assuming a (blood) of the pregnant woman at successive stages of maternal intake of 14 C resulting in a 1-jiCi blood gestation. These method6 include the contribution to the embryo/fetus dose from the resultant body bur dens of the declared pregnant woman and from activ ity in the embryo/fetus resulting from transfer across take on the 20th day of the pregnancy, the embryo/
fetus dose should be determined by multiplying the cumulated dose from an intake at day 31 (i.e., Table up
[
C3, Cumulated Dose column, 1.89E-04 rads) by the the placenta. Refer to Revision 1 to NUREG/ ratio of 20 days to 30 days (i.e., 20 divided by 30).
CR-5631 (Ref. 2) for a detailed description of the modeling. 3.2.2 For using the tabular dose data in cal culating the embryo/fetus dose, it may be assumed The methods and data of Revision 1 to NUREG/ that all intakes occurring within any of the 30-day pe CR-5631 (Ref. 2) may be used for determining the riods of gestation occur at the beginning of that pe dose to the embryo/fetus from maternal intakes at riod.5 The cumulated dose column should be used in successive stages of gestation for the radionuclides order to determine the total dose for the remainder of
3 H, 14C, 5 7Co, 58 Co, 6 0C0, 89 Sr, 9 0Sr, 10ORu, 1251, 1311, the gestation period.
1321, 133I, 134I, 135i, 134Cs, lSTCS, 233U, 234U, 2"5TU,
238U, 23 8pu, 239 Pu, and 24 1 Am. 3.2.3 For pre-existing body burdens from occupational exposure, the total burden determined The steps for determining the embryo/fetus dose to exist at time of pregnancy should be assumed to be using the Revision 1 to NUREG/CR-5631 (Ref. 2) available for uptake in the blood of the woman. The methods are as follows: dose should be assigned to the embryo/fetus as if the maternal blood uptake occurs within the first month
3.1 The methods presented in the regulatory po of pregnancy. The embryo/fetus dose is calculated by sition in Sections 2.1 through 2.4 should be used for multiplying the maternal burden of the radionuclide determining the uptake in the first transfer compart by its dose factor (Equation 3). The dose factor to be ment (blood) of the declared pregnant woman. used from the Appendix C tables is that factor corre sponding to the cumulated dose for a 0-day of gesta
3.2 Equations 1 and 2 of the regulatory position tion at radionuclide introduction (i.e., right-most col specified in Section 2.5 may be used for determining the embryo/fetus dose with the following clarifica umn, first data entry). However, for those radi onuclides with an "N" for this 0-day entry, the entry tions:
for the second gestation month should be used (i.e.,
3.2.1 For Equations I and 2, in place of the the right-most column, second data entry). Alterna dose factor parameter, DFi, the dose values should tively, time-dependent release kinetics may be used be taken from Appendix C to this guide for the time for calculating that fraction of the body burden that is period representing the time of intake relative to stage translocated to the blood through the duration of the of gestation. The data in Appendix C to this guide are pregnancy. The time-dependent release is described for an absorbed dose (in rads) from the introduction in ICRP Publications 30 and 54 (Refs. 3 and 6). This of 1 gCi of the radionuclide into the first transfer approach is complex, involving interlinking differen compartment (blood) of the woman at the beginning tial equations, and is considered outside the scope of of the specified month of gestation. To convert from a routine health physics program.
an absorbed dose (rad) to a dose equivalent (rem),
3.3 Doses from multiple nuclides and multiple the data in Appendix C should be multiplied by the intakes should be evaluated with a frequency corre appropriate quality factor from Table 1004 (b). 1 of 10
sponding to the intake (i.e., at least once every 30
CFR Part 20. For 3H, 14C, 5 7Co, 5 8 Co, 6 0Co, 89 Sr, days). Multiple dose determinations should be added
90
Sr, 10°Ru, 1251, 1311, 1321, 1331, 1341, 135], 13 4 Cs, and
137 Cs, a quality factor of 1 should be applied. For to determine the total dos
e. Doses may need to be
233 U, 234 U, 2 35U, 23 8 U, 238 Pu, 23 9pu, and 24lAm, a reevaluated if better estimates of intakes are provided by followup bioassay measurements.
quality factor of 20 should be applied, recognizing that most of the embryo/fetus dose results from alpha
D. IMPLEMENTATION
decay.
The purpose of this section is to provide informa For some radionuclides (e.g., 23 5U), a blood tion to applicants and licensees regarding the NRC
uptake at the beginning of the gestation period results staff's plans for using this regulatory guide.
in a negligible dose contribution to the embryo/fetus.
These radionuclides are identified in the tables in Ap Except in those cases in which an applicant pro pendix C to this guide by an "N" entry in the row for poses an acceptable alternative method of complying the 0-day of gestation at radionuclide introduction with specified portions of the Commission's regula (i.e., the first row of dose factor data). For an intake tions, the methods described in this guide will be used of these radionuclides within the first month of gesta tion, a time-weighted dose factor using the second 5 The correlation of intake to actual stage of gestation can only month data (3 1-day row) should be used. The 3 1-day be roughly estimated. For this reason, it is believed that the dose factor should be multiplied by the quotient of correlation should be limited to the best estimate of the month of gestation.
8.36-6
in the evaluation of applications for new licenses, li including supplements, Annals of the ICRP,
cense renewals, and license amendments and for Volume 2, No. 3/4, Pergamon Press Inc., 1979.
evaluating compliance with 10 CFR 20.1001
"1.2401. 4. K. F. Eckerman, A. B. Wolbarst, and A. C. B.
Richardson, "Limiting Values of Radionuclide REFERENCES Intake and Air Concentration and Dose Conver sion Factors for Inhalation, Submersion, and
1. International Commission on Radiological Pro Ingestion," Environmental Protection Agency, tection, "Age-Dependent Doses to Members of Federal Guidance Report No. 11 (EPA- 520/1 the Public from Intake of Radionuclides: Part 88-020), September 1988.
1," ICRP No. 56, Pergamon Press Inc., 1989.
5. International Commission on Radiological Pro
2. M. R. Sikov et al., "Contribution of Maternal tection, "The Metabolism of Compounds of Radionuclide Burdens to Prenatal Radiation Plutonium and Other Actinides," ICRP No. 19, Doses--Interim Recommendations," NUREG/ Pergamon Press Inc., May 1972.
CR-5631, Revision 1 (PNL-7445), U.S. Nu clear Regulatory Commission, March 1992. 6. International Commission on Radiological Pro tection, "Individual Monitoring for Intake of Radionuclides by Workers: Design and Interpre
3. International Commission on Radiological Pro tation," ICRP No. 54, Annals of the ICRP,
tection, "Limits for Intakes of Radionuclides by Volume 19, No. 1-3, Pergamon Press Inc.,
Workers," ICRP No. 30, Parts 1 through 4, 1988.
8.36-7
APPENDIX A
DOSE EQUIVALENT FACTORS FOR USE IN APPROXIMATING THE
EMBRYO/FETUS DOSE FROM RADIONUCLIDES IN MATERNAL BLOOD
Except as noted, the dose factors (DFi) pre into the first transfer compartment of the woman at sented in Table A-1 represent the committed dose any time during the gestation period. These entries equivalent to the uterus per introduction of unit activ are based on the modeling of Revision 1 to NUREG/
ity into the first transfer compartment (i.e., blood) of CR-5631 (Ref. A2) and are derived from the data the woman. These entries were calculated from tabu tables presented in Appendix C to this guide. The lated values of uterine committed dose equivalent per maximum calculated embryo/fetus dose (as presented unit intake and fractional absorption (fl) from the in the Appendix C tables) from intake by the de gastrointestinal tract using ICRP-30 (Ref. Al) meth clared pregnant woman during the gestation period odology. The DFi dose factors were derived by divid has been used for inclusion in Table A-1.
ing the committed dose equivalent per unit intake by the fractional absorption factor (fl). These dose fac The dose factor data presented in Revision 1 to tors are based on unit activity in the blood. The most NUREG/CR-5631 (Ref. A2) are for an absorbed conservative f, (i.e., largest fraction) for each radio dose expressed in units of rads. To adapt these data nuclide has been used for deriving the data in Table as presented in Appendix C to this guide for inclusion A-1. in Table A-i, appropriate quality factors have been applied to convert from rads to dose equivalent, ex For the radionuclides 3H, 14C, 57 Co, 68Co, SOCo, pressed in units of rem. For beta- and gamma-emit
89Sr, 9°Sr, 106Ru, 125I, 131j, 132j, 133I, 134I, 135j, 134Cs,
137 ting radionuclides, a quality factor of 1 has been ap Cs, 23U, 23U, 23U, ZaU, MSPu, ZaPu, and plied. For 2 wU, 234U, 235U, 238U, 238PU, 239pu, and
24
1Am, the dose factors in Table A-1 represent the 24 1 Am, a quality factor of 20 has been applied, recog maximum dose equivalent to the embryo/fetus for the nizing that most of the embryo/fetus dose results from gestation period from the introduction of unit activity the alpha decay.
A-I
L ;
TABLE A-1 Dose Equivalent Factors for Use in Approximating the Embryo/Fetus Dose from Radionuclides in Maternal Blood DFi DFi Nuclide DFi (rem/gCi) Nuclide (rem/ljCi) Nuclide (rem/ACi)
H-3 5.87E-05" Cr-51 6.96E-04 Ga-68 5.66E-02 Be-7 1.67E-02 Mn-51 3.65E-04 Ga-70 8.99E-05 Be-10 1.79E-02 Mn-52 4.70E-02 Ga-72 1.53E+00
C-11 1.21E-OS Mn-52m 2.80E-04 Ga-73 9.36E-02 C-14 1.29E-03* Mn-53 5.77E-05 Ge-66 1.42E-04 F-18 1.32E-05 Mn-54 1.86E-02 Ge-67 1.11E-05 Na-22 1.06E-02 Mn-56 2.18E-03 Ge-68 8.81E-04 Na-24 1.21E-03 Fe-52 1.30E-02 Ge-69 3.02E-04 Mg-28 3.83E-03 Fe-55 3.88E-03 Ge-71 6.99E-06 A1-26 5.33E-01 Fe-59 4.63E-02 Ge-75 1.61E-05 Si-31 3.85E-05 Fe-60 1.47E+00 Ge-77 3.40E-04 Si-32 4.33E-02 Co-55 4.01E-03 Ge-78 1.08E-04 P-32 3.03E-03 Co-56 3.43E-02 As-69 2.46E-05 P-33 4.33E-04 Co-57 2.20E-03* As-70 2.90E-04 S-35 3.53E-04 Co-58 9.17E-03" As-71 1.21E-03 CI-36 2.96E-03 Co-58m 5.17E-05 As-72 2.70E-03 CI-38 3.17E-05 Co-60 4.18E-02* As-73 3.02E-04 C1-39 3.89E-05 Co-60m 4.12E-07 As-74 2.90E-03 K-40 1.84E-02 Co-61 4.50E-05 As-76 1.11E-03 K-42 7.73E-04 Co-62m 5.33E-05 As-77 1.88E-04 K-43 7.10E-04 Ni-56 5.39E-02 As-78 1.85E-04 K-44 1.94E-05 Ni-57 3.60E-02 Se-70 1.61E-04 K-45 1.21E-05 Ni-59 2.71E-03 Se-73 3.66E-04 Ca-41 3.2 IE-05 Ni-63 6.29E-03 Se-73m 3.21E-05 Ca-45 6.6 1E-04 Ni-65 1.43E-03 Se-75 8.79E-03 Ca-47 5.18E-03 Ni-66 2.81E-03 Se-79 4.19E-03 Sc-43 2.48E+00 Cu-60 9.32E-05 Se-81 1.OOE-06 Sc-44 4.59E+00 Cu-61 2.69E-04 Se-81m 1.46E-05 Sc-44m 2.56E+01 Cu-64 2.09E-04 Se-83 3.62E-05 Sc-46 3.15E+O1 Cu-67 6.50E-04 Br-74 3.33E-05 Sc-47 1.86E+00 Zn-62 1.38E-03 Br-74m 6.18E-05 Sc-48 3.52E+01 Zn-63 5.92E-05 Br-75 6.07E-05 Sc-49 4.18E-04 Zn-65 3.49E-02 Br-76 1.20E-03 Ti-44 1.36E+00 Zn-69 3.09E-06 Br-77 3.27E-04 Ti-45 1.54E-02 Zn-69m 5.54E-04 Br-80 3.01E-06 V-47 2.29E-03 Zn-71m 5.75E-04 Br-80m 1.46E-04 V-48 4.37E-01 Zn-72 5.28E-03 Br-82 1. 87E-03 V-49 8.36E-05 Ga-65 9.18E-03 Br-83 2.72E-05 Cr-48 5.77E-03 Ga-66 9.95E-01 Br-84 2.56E-05 Cr-49 3.51E-04 Ga-67 2.50E-01 Rb-79 1. 15E-05
- Dose equivalent factor based on data presented in Revision 1 to NUREG/CR-5631 (Ref. A2). All other factors represent the committed dose equivalent to the uterus.
A-2
TABLE A-1 (continued)
DFi DFi - DFi Nuclide (rem/4Ci) Nuclide (reml/gCi) Nuclide (rem/gCi)
Rb-81 8.18E-05 Nb-90
- 2.39E-01 Rh-105 1.93E-03 Rb-8 lm 1.08E-05 Nb-93m 9.29E-04 Rh-106m 6.86E-03 Rb-82m 3.49E-04 Nb-94 3.04E-01 Rh-107 8.511E-05 Rb-83 7.07E-03 Nb-95 1.24E-01 Pd-100 3.94E-01 Rb-84 1.05E-02 Nb-95m 1.27E-02 Pd-101 3.33E-02 Rb-86 8.14E-03 Nb-96 2.03E-01 Pd-103 1.39E-03 Rb-87 4.22E-03 Nb-97 4.11E-03 Pd-107 7.33E-06 Rb-88 1.02E-05 Nb-98 9.66E-03 Pd-109 1.27E-03 Rb-89 1.20E-05 Mo-90 7.77E-04 Ag-102 3.76E-04 Sr-80 3.96E-04 Mo-93 4.36E-04 Ag-103 8.58E-04 Sr-81 1.22E-04 Mo-93m 4.76E-04 Ag-104 3.05E-03 Sr-82 1.25E-02 Mo-99 9.39E-04 Ag-104m 1.09E-03 Sr-83 2.31E-03 Mo-101 1.48E-05 Ag-105 1.94E-02 Sr-85 4.03E-03 Tc-93 1.33E-04 Ag-106 2.12E-04 Sr-85m 4.8 1E-05 Tc-93m 4.67E-05 Ag-106m 8.21E-02 Sr-87m 1. 62E-04 Tc-94 4.566E-04 Ag-108m 6.59E-02 Sr-89 1.84E-02" Tc-94m 7.08E-05 Ag-110in 1.04E-01 Sr-90 5.22E-02* Tc-95 3.86E-04 Ag-111 1.41E-03 Sr-91 1.49E-03 Tc-95m 1.23E-03 Ag-i112 2.18E-03 Sr-92 7.79E-04 Tc-96 2.62E-03 Ag-115 1.98E-04 Y-86 2.18E+01 Tc-96m 2.29E-05 Cd-104 3.30E-03 Y-86m 1.26E+00 Tc-97 4.67E-05 Cd-107 1.95E-04 Y-87 1.01E+01 Tc-97m 2.42E-04 Cd-109 2.12E-02 Y-88 3.96E+01 Tc-98 2.97E-03 Cd-i113 2.77E-01 Y-90 4.66E-04 Tc-99 2.79E-04 Cd-113m 2.55E-01 Y-90m 1.21E+00 Tc-99m 3.32E-05 Cd- 115 9.47E-03 Y-91 6.03E-02 Tc-101 2.96E-06 Cd-l15m 1.27E-02 Y-9 1m 2.13E-01 Tc-104 2.07E-05 Cd-117 4.23E-03 Y-92 4.81E-01 Ru-94 2.32E-03 Cd-117m 9.62E-03 Y-93 4.18E-01 Ru-97 6.89E-03 In-109 7.95E-03 Y-94 1.10E-01 Ru-103 1.97E-02 In-1l0 4.01E-02 Y-95 3.56E-02 Ru-105 4.09E-03 In-110 4.50E-03 Zr-86 8.62E-01 Ru-106 7.23E-03* In-Ill 3.05E-02 Zr-88 3.87E-01 Rh-99 2.19E-02 In-112 9.47E-05 Zr-89 7.31E-01 Rh-99m 3.5 1E-03 In- 1i3m 1.24E-03 Zr-93 8.79E-05 Rh--100 3.86E-02 In-i 14m 3.05E-02 Zr-95 6.16E-01 Rh-101 3.33E-102 In-115 8.99E-01 Zr-97 5.24E-01 Rh-101m 9.40E-03 In-l 15m 2.16E-03 Nb-88 1.17E-03 Rh-102 1.93E-01 In-l 16m 4.92E-03 Nb-89 1.83E-02 Rh-102m 3.48E-02 In-i 17 1.22E-03 Nb-89 1.30E-02 Rh-103m 1.18E-06 In-I17m 2.61E-03
- Dose equivalent factor based on data presented in Revision I to NUREG/CR-5631 (Ref. A2). All other factors represent the committed dose equivalent to the uterus.
A-3
TABLE A-1 (continued)
DFi DFi Nuclide (rem/!gCi) DFi Nuclide (rem/gCi) Nuclide (rem/gCi)
In-1 19m 1.39E-05 Te-127m 1. 82E-03 Ba-131m 1.32E-05 Sn-110 2.1IE-02 Te-129 2.35E-05 Ba-133 1.27E-02 Sn-ill 8.8 1E-04 Te-129m 3.39E-03 Ba-133m 8.77E-04 Sn-1l3 2.63E-02 Te-131 2.18E-04 Ba-135m 7.03E-04 Sn-il7m 1.57E-02 Te-131m 6.64E-03 Ba-139 4.55E-05 Sn-119m 2.29E-03 Te-132 8.57E-03 Ba-140 1.54E-02 Sn-121 3.70E-05 Te-133 3.26E-05 Ba-141 9.47E-05 Sn-121m 5.70E-03 Te-133mn 5.48E-04 Ba-142 2.74E-04 Sn-123 6.35E-03 Te-134 3.98E-04 La-131 3.77E-02 Sn-123m 2.48E-04 i-120 9.36E-05 La-132 5.07E-01 Sn-125 2.37E-02 l-120m 8.73E-05 La-135 3.43E-02 Sn-126 2.35E-01 1-121 1.79E-05 La-137 7.55E-02 Sn-127 1.14E-02 1-123 2.27E-05 La-138 2.84E+00
Sn-128 7.14E-03 1-124 2.16E-04 La-140 2.32E+00
Sb-i 15 2.OOE-04 1-125 1.38E-03* La-141 9.43E-03 Sb-I 16 1.59E-04 1-126 2.23E-04 La-142 1.91E-01 Sb-116m 1.49E-03 1-128 5.25E-06 La-i43 2.85E-03 Sb-i 17 3.34E-04 1-129 5.11E-04 Ce-134 3.13E+00
Sb-1 18m 6.59E-03 1-130 2.29E-04 Ce-135 4.44E+00
Sb- 119 2.08E-04 1-131 3.64E-03" Ce-137 7.13E-02 Sb-120 3.70E-05 1-132 1.56E-04* Ce-137m 3.31E-01 Sb-120 3.42E-02 1-132m 6.14E-05 Ce-139 I. 15E+00
Sb-122 5.85E-03 1-133 9.04E-04* Ce-14i 5.56E-01 Sb-124 2.98E-02 1-134 4.83E-05* Ce-i43 1.05E+00
Sb-124m 4.88E-05 1-135 3.72E-04" Ce-144 3.79E-01 Sb-125 8.5IE-03 Cs-125 1.33E-05 Pr-136 4.12E-02 Sb-126 4.37E-02 Cs-127 5.96E-05 Pr-137 1.26E-01 Sb-126m 1.69E-04 Cs-129 2.13E-04 Pr-138m 9.61E-01 Sb-127 9.66E-03 Cs-130 6.99E-06 Pr-139 1.16E-01 Sb-128 1.33E-04 Cs-131 2.27E-04 Pr-142 1.36E-01 Sb-128 8.73E-03 Cs-132 2. 1OE-03 Pr-142m 1.73E-03 Sb-129 3.36E-03 Cs-134 1.IiE-01* Pr-143 4.53E-08 Sb-130 9.40E-04 Cs-134m 2.66E-05 Pr-144 8.44E-04 Sb-131 3.36E-04 Cs-135 7.07E-03 Pr-145 1.41E-02 Te-116 1.45E-03 Cs-135m 2.42E-05 Pr-147 1.95E-02 Te-121 4.87E-03 Cs-136 1.42E-02 Nd-136 3.59E-01 Te-121m 7.90E-03 Cs-137 5.94E-02* Nd-138 8.26E-01 Te-123 3.09E-05 Cs-138 2.95E-05 Nd-139 4.1IE-02 Te-123m 2.94E-03 Ba-126 1.14E-03 Nd-139m 1.74E+00
Te-125m 9.75E-04 Ba-128 1. 17E-02 Nd-141 4.33E-02 Te-127 6.31E-05 Ba-131 7.40E-03 Nd-147 8.45E-01
"Dose equivalent factor based on data presented in Revision
1 to NUREG/CR-5631 (Ref. A2). All other factors committed dose equivalent to the uterus. represent the A-4
TABLE A-1 (continued)
DFi DFi DFi Nuclide (rem/gCi) Nuclide (rem/gCi) Nuclide (rem/!gCi)
Nd-149 1.37E-01 Gd-149 2.47E+00 Tm-166 2.37E+00
Nd-15 1 2.53E-02 Gd-151 4.99E-01 Tm-167 1.03E+00
Pm-141 3.63E-02 Gd-152 0.OOE-01 Tm-170 5.38E-02 Pm-143 1.79E+00 Gd-153 8.92E-01 Tm-171 8.13E-03 Pm-144 8.68E+00 Gd-159 1.52E-01 Tm-172 1.89E+00
Pm-145 2.58E-01 Tb-147 6.76E-01 Tm-173 5.88E-01 Pm-146 4.34E+00 Tb-149 1.27E+00 Tm-175 2.70E-02 Pm-147 3.49E-05 Tb-150 1.01E+00 Yb-162 8.97E-02 Pm-148 2.60E+00 Tb-151 2.33E+00 Yb-166 6.08E+00
Pm-148m 1.08E+01 Tb-153 1.16E+00 Yb- 167 1.23E-02 Pm-149 4.70E-02 Tb-154 5.65E+00 Yb-169 2.47E+00
Pm-150 6.86E-OI Tb-155 9.52E-01 Yb-175 2.10E-01 Pm--151 I. 1IE+00 Tb-156 8.65E+00 Yb-177 6.98E-02 Sm-141 4.11E-02 Th-156m 9.32E-01 Yb-178 4.11E-02 Sm-141m 1.42E-01 Tb-156m 2.89E-01 Lu-169 3.60E+00
Sm-142 2.11E-01 Tb-157 2.39E-02 Lu-170 8.42E+00
Sm-145 5.56E-01 Tb-158 4.79E+00 Lu-171 3.72E+00
Sm-146 0.OOE-01 Tb-160 6.08E+00 Lu-172 9.20E+00
Sm-147 0.OOE-01 Tb-161 2.64E-01 Lu-173 1.10E+00
Sm-151 1.26E-05 Dy-155 1.08E+00 Lu-174 8.93E-01 Sm-153 3.54E-01 Dy-157 5.8 1E-01 Lu-174m 5.54E-01 Sm-155 5.65E-03 Dy-159 4.19E-01 Lu-176 3.45E+00
Sm-156 3.55E-01 Dy-165 1.3SE-02 Lu-176m 1.53E-0
Eu-145 2.OOE+00 Dy-166 3.56E-01 Lu-177 2.24E-0 1 Eu-146 3.38E+00 Ho-155 1.41E-01 Lu-177m 6.80E+00
Eu-147 8.51E-01 Ho-157 2.57E-02 Lu-178 8.18E-03 Eu-148 3.53E+00 Ho-159 3.47E-02 Lu-178m 5.54E-02 Eu-149 1.40E-01 Ho-161 4.70E-02 Lu-179 3.03E-02 Eu-150 2.92E-02 Ho-162 4.66E-03 Hf-170 4.74E-01 Eu-150 3.02E+00 Ho-162m 1.43E-01 Hf-172 4.63E-01 Eu-152 2.20E+00 Ho-164 3. 1OE-03 Hf-173 2.26E-01 Eu-152m 1.38E-01 Ho-164m 1.32E-02 Hf-175 3.70E-01 Eu-154 2.28E+00 Ho-166 1.04E-01 Hf-177m 5.22E-02 Eu-155 1.60E-01 Ho-166m 1.07E+01 Hf-178m 2.94E+00
Eu-156 1.90E+00 Ho-167 2.38E-01 Hf-179m 8.51E-01 Eu-157 2.01E-01 Er-161 6.29E-01 Hf-180m .71E-01 Eu-158 3.56E-02 Er-165 1. 12E-01 Hf-181 4.96E-01 Gd-145 1.09E-01 Er-169 1.34E-04 Hf-182 1.16E+00
Gd-146 4. 11E+00 Er-171 5.88E-01 Hf-182m 2.61E-02 Gd-i47 4.9 iE+00 Er-172 2.59E+00 Hf-183 2.33E-02 Gd-148 0.OOE-01 Tm-162 6.87E-02 Hf-184 1.94E-01 A-5
TABLE A-1 (continued)
DFi DFi Nuclide DFi (rem/pCi) Nuclide (rem/gCi) Nuclide (rem/gCi)
Ta-172 4.07E-02 Os-189m 5.1IE-06 Hg-193m 3.23E-04 Ta-173 1.94E-01 Os-191 1.99E-02 Ta-174 Hg-194 1.81E-01
4.25E-02 Os-191m 1. 12E-03 Hg-195 7.47E-05 Ta-175 4.96E-01 Os-193 8.55E-03 Hg-195m 5.48E-04 Ta-176 8.25E-01 Os-194 8.69E-02 Hg-197 2.38E-04 Ta-177 1.30E-01 Ir-182 2.23E-03 Hg-197m 2.97E-04 Ta-178 1.47E-01 Ir-184 3.24E-02 Hg-199m 7.55E-06 Ta-179 9.40E-02 Ir-185 3.85E-02 Hg-203 5.33E-03 Ta-180 1.16E+00 Ir-186 1.12E-01 T1-194 6.44E-06 Ta-180m 3.47E-02 Ir-187 2.08E-02 Ti-194m 2.16E-05 Ta-182 2.15E+00 Ir-188 1.60E-01 TI-195 3.49E-05 Ta-182m 2.65E-03 Ir-189 1.96E-02 Ti-197 3.85E-05 Ta-183 5.44E-01 Ir-190 2.52E-01 TI-198 1.94E-04 Ta-184 7.40E-01 Ir-190m 1.OIE-03 TI-198m 8.36E-05 Ta-185 9.25E-03 Ir-192 1. 63E-0 1 T1-199 5.55E-05 Ta-186 7.03E-03 Ir-192m 8.99E-02 T1-200 6.55E-04 W-176 6.55E-04 Ir-194 7.55E-03 TI-201 2.48E-04 W-177 3.66E-04 Ir-194m 4.55E-01 TI-202 1.38E-03 W-178 6.43E-04 Ir-195 1.24E-03 Tl-204 2.43E-03 W-179 8.12E-06 Ir-195m 1.03E-02 Pb-195m W-181 W-185 W-187
2.80E-04
3.51E-07
1.04E-03 Pt-186 Pt-188 Pt-.189
2.06E-02
1.21E-01
2.08E-02 Pb-198 Pb-199
1.65E-04
3.92E-04
6.5IE-04 L
Pb-200 3.37E-03 W-188 1.68E-04 Pt-191 4.88E-02 Pb-201 1.78E-03 Re-177 1.49E-05 Pt-193 1.07E-04 Pb-202 6.77E-02 Re-178 8.37E-06 Pt-193m 2.71E-03 Pb-202m 1.91E-03 Re-181 4.61E-04 Pt-195m 1.58E-02 Pb-203 2.02E-03 Re-182 4.56E-04 Pt-197 2.64E-03 Pb-205 3.63E-04 Re-182 1.92E-03 Pt-197m 1.12E-03 Pb-209 9.93E-06 Re-184 1.64E-03 Pt-199 5.40E-04 Pb-2 10 2.31E+00
Re-184m 1.31E-03 Pt-200 2.04E-02 Pb-211 3.63E-04 Re-i86 4.53E-04 Au-193 1.63E-03 Pb-212 3.29E-02 Re-186m 9.43E-04 Au-194 1.10E-02 Pb-214 5.64E-04 Re-187 1.82E-06 Au-195 2.35E-03 Bi-200 1.66E-03 Re-188 3.73E-04 Au-198. 5.66E-03 Bi-201 4.07E-03 Re-188m 8.19E-06 Au-198m 1.05E-02 Bi-202 4.83E-03 Re-189 2.46E-04 Au-199 1.68E-03 Bi-203 2.54E-02 Os-180 1.78E-03 Au-200. 1.01E-04 Bi-205 4.82E-02 Os-181 1.75E-02 Au-200m 1.61E-02 Bi-206 9.03E-02 Os-182 1.07E-01 Au-201 1. 15E-05 Bi-207 4.88E-02 Os-185 1.33E-01 Hg-193 4.88E-05 Bi-210 1.46E-03 A-6
TABLE A-1 (continued)
DFi DFi DFi Nuclide (rem/pCi) Nuclide (rem/gCi) Nuclide (rem/gCi)
Bi-210m 8.66E-02 U-233 5.84E-01* Am-245 2.68E-04 Bi-212 1.70E-03 U-234 5.84E-01" Am-246m 1.51E-02 Bi-213 4.36E-04 U-235 5.34E-01* Am-246 2.03E-02 Bi-214 3.52E-04 U-236 1.81E-01 Cm-238 1.31E-01 Po-203 1.07E-03 U-237 5.42E-03 Cm-240 3.50E-02 Po-205 1.64E-03 U-238 5.10E-01* Cm-241 8.69E-01 Po-207 4.03E-03 U-239 5.52E-05 Cm-242 3.30E-02 Po-210 3.05E+00 U-240 4.17E-03 Cm-243 3.74E-01 At-207 8.32E-04 Np-232 8.69E-03 Cm-244 3.19E-02 At-211 3.92E-02 Np-233 2.85E-03 Cm-245 3.11E-01 Fr-222 2.13E-03 Np-234 1.45E+00 Cm-246 1.27E-01 Fr-223 8.58E-03 Np-235 2.99E-03 Cm-247 9.51E-01 Ra-223 7.84E-01 Np-236 4.29E-01 Cm-248 3.49E+01 Ra-224 3.85E-01 Np-236 5.25E-02 Cm-249 1.07E-03 Ra-225 6.23E-01 Np-237 3.59E-01 Cm-250 2.76E+02 Ra-226 1.69E+00 Np-238 6.07E-01 Bk-245 4.11E-01 Ra-227 6.10E-05 Np-239 2.55E-01 Bk-246 1.04E+00
Ra-228 2.90E+00 Np-240 7.07E-02 Bk-247 2.83E-01 Ac-224 9.47E-02 Pu-234 1.24E-01 Bk-249 8.40E-04 Ac-225 3.68E-01 Pu-235 1.72E-03 Bk-250 1.54E-01 Ac-226 1.66E-01 Pu-236 6.81E-02 Cf-244 9.25E-05 Ac-227 2.60E-01 Pu-237 1.07E-01 Cf-246 2.88E-02 Ac-228 3.12E-0I Pu-238 1.11E+00* Cf-248 4.18E-02 Th-226 3.02E-03 Pu-239 1.04E+00* Cf-249 9.80E-01 Th-227 3.52E+00 Pu-240 2.80E-02 Cf-250 3.30E-01 Th-228 4.40E+O1 Pu-241 2.96E-04 Cf-251 4.26E-01 Th-229 8.51E+01 Pu-242 2.81E-02 Cf-252 1.15E+0O1 Th-230 1.26E+01 Pu-243 9.62E-03 Cf-253 8.55E-04 Th-231 8.97E-02 Pu-244 1.07E+00 Cf-254 3.70E+02 Th-232 2.26E+01 Pu-245 2.22E-01 Es-250 4.77E-02 Th-234 2.33E-01 Pu-246 1.34E+00 Es-251 1.24E-01 Pa-227 2.42E-03 Am-237 2.60E-02 Es-253 3.58E-02 Pa-228 9.58E-01 Am-238 7.81E-02 Es-254m 5.22E-01 Pa-230 1.04E+00 Am-239 1.63E-01 Es-254 1.33E+00
Pa-231 2.25E-01 Am-240 1.16E+00 Fm-252 2.61E-02 Pa-232 8.95E-01 Am-241 2.22E-01" Fm-253 1.38E-01 Pa-233 3.81E-01 Am-242m 3.64E-02 Fm-254 6.11E-03 Pa-234 6.77E-01 Am-242 1.32E-02 Fm-255 2.85E-02 U-230 6.13E-01 Am-243 4.74E-01 Fm-257 2.60E-01 U-231 2.63E-03 Am-244m 1.05E-05 Md-257 3.69E-02 U-232 6.02E-01 Am-244 3.92E-01 Md-258 5.96E-02
- Dose equivalent factor based on data presented in Revision 1 to NUREG/CR-5631 (Ref. A2). All other factors represent the committed dose equivalent to the uterus.
A-7
REFERENCES
Al. International Commission on Radiological Pro tection, "Limits for Intakes of Radionuclides by A2. M. R. Sikov et al., "Contribution of Maternal Workers," ICRP No. 30, Parts I through 4, Radionuclide Burdens to Prenatal Radiation including supplements, Annals of the ICRP, Dose-Interim Recommendations," NUREG/
Volume 2, No. 3/4, Pergamon Press Inc., 1979. CR-5631, Revision 1 (PNL-7445), U.S. Nu clear Regulatory Commission, March 1992.
I
A-8
APPENDIX B
BLOOD UPTAKE FRACTIONS FOR INGESTED ACTIVTY
Element fi Element fl Actinium IE-3 Einsteinium 1E-3 (Ac) (Es)
Aluminum IE-2 Erbium 3E-4 (Al) (Er)
Americium 1E-3 Europium 1E-3 (Am) (Eu)
Antimony 1E-1 Fermium 1E-3 (Sb) (Fm)
Arsenic 5E-1 Fluorine 1E0
(As) (F)
Astatine 1E0 Francium 1E0
(At) (Fr)
Barium IE-l Gadolinium 3E-4 (Ba) (Gd)
Berkelium 1E-3. Gallium 1E-3 (Bk) (Ga)
(Be) (Ge)
Bismuth 5E-2 Gold 1E-1 (Bi) (Au)
Bromine 1E0 Hafnium 2E-3 (Br) (Hf)
Cadmium 5E-2 Holmium 3E-4 (Cd) (Ho)
(Ca) (H)
Californium 1E-3 Indium 2E-2 (Co (In)
(C) .(I)
Cerium 3E-4 Iridium 1E-2 (Ce) (Ir)
Cesium 1E0 Iron 1E-1 (Cs) (Fe)
Chlorine 1E0 Lanthanum lE-3 (Cl) (La)
Chromium iE-I Lead 2E-1 (Cr) (Pb)
Cobalt 3E-1 Lutetium 3E-4 (Co) (Lu)
Copper 5E-1 Magnesium 5E-1 (Cu) (Mg)
Curium 1E-3 Manganese IE-1 (Cm) (Mn)
Dysprosium 3E-4 Mendelevium lE-3 (Dy) (Md)
B-1
APPENDIX B (continued)
Element fl Element fi Mercury 1EO Selenium 8E-1 (Hg) (Se)
Molybdenum 8E-1 Silicon 1E-2 (Mo) (Si)
Neodymium 3E-4 Silver 5E-2 (Nd)
(Ag)
Neptunium 1E-3 (Np) Sodium lEO
(Na)
Nickel 5E-2 (Ni) Strontium 3E-I
(Sr)
Niobium 1E-2 (Nb) Sulfur 8E-i (s)
Osmium 1E-2 (Os) Tantalum 1E-3 (Ta)
Palladium 5E-3 (Pd) Technetium 8E-1 (Tc)
Phosphorus 8E-1 (P) Tellurium 2E-1 Platinum (Te)
1E-2 (Pt) Terbium 3E-4 Plutonium 1E-3 (Tb)
(Pu) Thallium 1EO
(Po)
Thorium 2E-4 Potassium 1EO (Th)
(K)
Thulium 3E-4 Praseodymium 3E-4 (Tm)
(Pr)
(Pm)
Titanium 1E-2 Protactinium 1E-3 (Pa) (Ti)
2E-1 (Ra) (W)
8E-1 (Re) (U)
Rhodium 5E-2 Vanadium 1E-2 (Rh) (V)
Rubidium 1EO Ytterbium 3E-4 (Rb) (Yb)
Ruthenium 5E-2 Yttrium 1E-4 (Ru) (Y)
Samarium 3E-4 Zinc 5E-1 (Sm) (Zn)
Scandium 1E-4 Zirconium 2E-3 (Sc) (Zr)
B-2
APPENDIX C
RADIATION ABSORBED DOSE TO THE EMBRYO/FETUS
FOLLOWIN
G. INTRODUCTION
OF SPECIFIED RADIONUCLIDES AND
CHEMICAL FORMS INTO THE MATERNAL TRANSFER COMPARTMENT (BLOOD)
The entries for selected radionuclides and chemi As noted in Revision 1 to NUREG/CR-5631 cal forms in the tables in this appendix have been (Ref. Cl), ICRP Publication 30 (Ref. C2) employs a calculated from the modeling presented in Revision I metabolic model in which a fraction of activity in the to NUREG/CR-5631 (Ref. Cl). It has been assumed first transfer compartment (blood) often is assumed that 1 jiCi of activity is introduced into the maternal to go immediately to excretion. Because of the minus transfer compartment (blood). Pregnancy is assumed cule mass of the embryo/fetus immediately following to begin at the time of fertilization, roughly 2 weeks fertilization, for some materials the biokinetic model after menses, and gestation is considered to consist of thus predicts that there would be negligible initial ac nine 30-day months. tivity in the embryo after administration at that time, and that there would be minimal activity at later times. As a consequence, the dose rate and doses Radiation dose rates were calculated from the in also would be negligible, which is indicated by N in itial fraction that was present after a single administra the table. For these nuclides, an approximation of the tion at the start of each of these months or on the cumulative dose for an intake occurring during the assumed final day (day 270) of gestation. Monthly first 30 days should be made based on a time doses were determined by integrating under the curve weighted average of the 31-day intake data. The cu relating the fraction of the activity in the embryo/fetus mulative dose from an intake in the first 30 days of at the start of each month after administration and pregnancy may be estimated by multiplying the
31-day cumulated dose value by the ratio of the days the fraction at the beginning of the subsequent month to-date in the first month to a 30-day period. For ex of gestation. Monthly doses are shown for the inclu ample, assuming a maternal intake of 14C resulting in sive periods, expressed in days. Doses to the embryo/ a I-RCi blood uptake on the 20th day of the preg fetus from radionuclides in maternal organs were cal nancy, the gestation dose should be determined by culated; when appropriate, these are included to pro multiplying the cumulated dose from an intake at day vide total radiation absorbed doses. The tabulated 31 (i.e., Table C3, Cumulated Dose column, ialues of cumulated doses were determined as the 1.89E-04 rads) by the ratio of 20 days to 30 days sum of the monthly doses. (i.e., 20 divided by 30).
C-1
Table C1 Radiation Doses to the Embryo/Fetus from 1 gCi of 3H, as Tritiated Water, Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction 0-30 31-60 Dose
61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 9.03E-06 3.96E-11 7.*71*.-1 14 2.OOE-15 5.31E-17 2.63E-18 1.72E-19 1.34E-20 1.18E-21 9.03E-06
31 1.77E-05 2.64E-0 )8 7.50E-10 1.94E-11 9.70E-13 6.30E-14 4.94E-15 4.33E-16 1.77E-05
,61 3.93E-0 '5 8.96E-07 2.47E-08 1.21E-09 7.91E-11 6.17E-12 5.41E-13 4.02E-05
91 3.82E-05 1.06E-06 5.19E-08 3.39E-09 2.64E-10 2.32E-11 3.93E-05
121 4.50E-05 2.14E-06 1.41E-07 1.10E-08 9.63E-10 4.73E-05
151 4.98E-05 3.22E-06 2.53E-07 2.21E-08 5.33E-05
181
5.28E-05 4.08E-06 3.57E-07 5.72E-05
211
241
5.40E-05 4.70E-06 5.87E-05
5.28E-05 5.28E-05 Table C2 C.) Radiation Doses to the Embryo/Fetus from 1 pCi of 3H, as a Hexose or Amino Acid, Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction A
Nj*u'A
31-60 61-90 Dose
91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 -N N N . N N N N N N
31 2.21E-05 2.14E-07 4.68E-08 1.04E-08 4.37E-09 2.35E-09 1.50E-09 1.06E-09 2.24E-05
61 6.OOE-05 7.27E-06 1.67E-06 6.81E-07 3.68E-07 2.34E-07 1.66E-07 7.04E-05
91 5.82E-05 9.25E-06 3.69E-06 1.97E-06 1.26E-06 8.92E-07 7.53E-05
121 7.24E-05 1.97E-05 1.03E-05 6.50E-06 4.62E-06 1. 14E-04
151 8.29E-05 3.05E-05 1.89E-05 1.33E-05 1.46E-04
181
8.96E-05 3.93E-05 2.72E-05 1.56E-04
211
9.31E-05 4.58E-05 1.39E-04
241
1.05E-04 1.OSE-04 N indicates that the metabolid pattern is such that the dose rates and doses would be negligible fertilization. Approximations of doses resulting from administration during the throughout gestation when activity is administered immediately after first month are described on page C-1.
Table C3 Radiation Doses to the Embryo/Fetus from 1 jiCi of 14C, as a Bicarbonate, Hexose, Amino Acid, Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestatio )n Periods (days) Cumulated
0-30 31-60 Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 21i-240 241-270 0-270
0 N* N N N N N N N N N
31 1.87E-04 1.72E-06 4.12E-07 9.18E-08 3.88E-08 2.09E-08 1.34E-08 9.56E-09 1.89E-04
61 4.96E-04 5.83E-05 1.46E-05 6.02E-06 3,26E-06 2.09E-06 1.49E-06 5.82E-04
91 4.8 1E-04 7.48E-05 3.24E-05 1.74E-05 1.IIE-05 7.95E-06 6.25E-04
121 5.96E-04 1.59E-04 9.09E-05 5.74E-05 4.1IE-05 9.44E-04
151 6.80E-04 2.47E-04 1.66E-04 1. 17E-04 1.21E-03
181 7.33E-04 3.19E-04 2.39E-04 1.29E-03
211
7.61E-04 3.70E-04 1.13E-03
241
8.88E-04 8.88E-04 Table C4 Radiation Doses to the Embryo/Fetus from 1 gCi of 5 7Co Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indic*ated Gestation Periods (days) Cumulated Introduction 0-30 151-180 181-210 211-240 241-270 Dose
0-270
31-60 61-90 91-120 121-150
0 7.30E-04 2.76E-04 2.36E-04 1.97E-04 1.75E-04 1.56E-04 1.39E-04 1.23E-04 1.09E-04 2.14E-03
31 8.66E-04 2.74E-04 2.45E-04 2.07E-04 1.82E-04 1.60E-04 1.41E-04 1.24E-04 2.20E-03
61 8.71E-04 2.82E-04 2.56E-04 2.15E-04 1.88E-04 1.63E-04 1.42E-04 2.12E-03
91 8.96E-04 2.96E-04 2.67E-04 2.22E-04 1.91E-04 1.64E-04 2.04E-03
121 9.37E-04 3.08E-04 2.75E-04 2.25E-04 1.92E-04 1.94E-03
151 9.78E-04 3.18E-04 2.79E-04 2.27E-04 1.80E-03
181 1.01E-03 3.22E-04 2.83E-04 1.61E-03
211
1.03E-03 3.19E-04 1.35E-03
241
1.04E-03 1.04E-03
- N indicates that the metabolic pattern is such that the dose rates and doses would be negligible throughout gestation when activity is administered immediately after fertilization. Approximations of doses resulting from administration during the first month are described on page C-1.
Table C5 Radiation Doses to the Embryo/Fetus from 1 gCi of 68Co, Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestatio 9n Periods (days) Cumulated Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 4.81E-03 1.27E-03 9.03E-04 6.03E-04 4.25E-04 3.OOE-04 2.13E-04 1.52E-04 1.09E-04 8.79E-03
31 5.12E-03 1.30E-03 9.30E-04 6.24E-04 4.37E-04 3.06E-04 2.15E-04 1.53E-04 9.08E-03
61 5.26E-03 1.34E-03 9.62E-04 6.41E-04 4.45E-04 3.09E-04 2.17E-04 9.17E-03
91 5.39E-03 1.38E-03 9.88E-04 6.54E-04 4.49E-04 3.11E-04 9.17E-03
121 5.59E-03 1.42E-03 1.01E-03 6.59E-04 4.53E-04 9.13E-03
151 5.75E-03 1.45E-03 1.02E-03 6.64E-04 8.88E-03
181 5.87E-03 1.46E-03 1.03E-03 8.36E-03
211
241 5.95E-03 1.45E-03 7.40E-03
6.OOE-03 6.00E-03 Table C6 Radiation Doses to the Embryo/Fetus from 1 jiCi of 6oCo, Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (day Cumulated ys) Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 1.28E-02 4.73E-03 4.37E-03 3.79E-03 3.60E-03 3.40E-03 3.22E-03 3.05E-03 2.88E-03 4.18E-02
31 1.38E-02 4.73E-03 4.40E-03 3.98E-03 3.73E-03 3.48E-03 3.26E-03 3.06E-03 4.04E-02
61 1.39E-02 4.76E-03 4.62E-03 4.12E-03 3.8 1E-03 3.52E-03 3.27E-03 3.80E-02
91 1.40E-02 4.99E-03 4.79E-03 4.22E-03 3.86E-03 3.54E-03 3.54E-02
121 1.46E-02 5.17F-03 4.90E-03 4.27E-03 3.88E-03 3.28E-02
151 1.52E-02 5.29E-03 4.96E-03 4.29E-03 2.97E-02
181 1.56E-02 5.35E-03 5.01E-03 2.60E-02
211
1.59E-02 5.29E-03 2.12E-02
241
1.60E-02 1.60E-02
Table C7 Radiation Doses to the Embryo/Fetus from 1 gCi of 57Co, as Vitamin B-12, Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 1.47E-03 1.11E-03 7.18E-04 4.88E-04 3.34E-04 2.28E-04 1.54E-04 1.02E-04 6,74E-05 4.67E-03
31 1.67E-03 1.10E-03 7.44E-04 5.1OE-04 3.48E-04 2.35E-04 1.56E-04 1.03E-04 4.87E-03
61 1,68E-03 1.14E-03 7.80E-04 5.31E-04 3.59E-04 2.38E-04 1.57E-04 4.89E-03
91 1.74E-03 1.19E-03 8.13E-04 5.49E-04 3.64E-04 2.40E-04 4.90E-03
121 1.82E-03 1.24E-03 8.38E-04 5.56E-04 3.67E-04 4.82E-03
151 1.89E-03 1.28E-03 8.48E-04 5.60E-04 4.58E-03
181 1.95E-03 1.30E-03 8.55E-04 4.1OE-03
211 1.98E-03 1.31E-03 3.29E-03
241 1.99E-03 1.99E-03 Table C8 Radiation Doses to the Embryo/Fetus from 1 gCi of 6oCo, as Vitamin B-12, Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (da~ys) Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 .181-210 211-240 241-270 0-270
0 2.54E-02 1.90E-02 1.33E-02 9.38E-03 6.88E-03 4.98E-03 3.56E-03 2.52E-03 1.77E-03 8.68E-02
31 2.71E-02 1.90E-02 1.34E-02 9.82E-03 7. 1OE-03 5.09E-03 3.61E-03 2.53E-03 8.76E-02
61 2.70E-02 1.91E-02 1.40E-02 1.02E-02 7.28E-03 5.16E-03 3.62E-03 8.64E-02
91 2.74E-02 2.OOE-02 1.45E-02 1.04E-02 7,38E-03 5.18E-03 8.49E-02
121 2.86E-02 2.08E-02 1.49E-02 1.05E-02 7.4 1E-03 8.22E-02
151 2.97E-02 2.13E-02 1.5 1E-02 1.06E-02 7.67E-02
181 3.04E-02 2.15E-02 1.51E-02 6.70E-02
211 3.08E-02 2.16E-02 5.24E-02
Table C9 Radiation Doses to the Embryo/Fetus from 1 jiCi of 89Sr Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction 0-30 31-60 61-90 91-120 121-150 151-180 Dose
181-210 211-240 241-270 0-270
0 4.09E-03 5.66E-04 2.92E-04 1.37E-04 6.64E-05 3.59E-05 2.10E-05 1.23E-05 7.01E-06 5.23E-03
31 5.35E-03 5.74E-04 2,95E-04 1.36E-04 6.57E-05 3.53E-05 2.05E-05 1.20E-05 6.49E-03
61 9.01E-03 1.20E-03 3.84E-04 1.63E-04 7.45E-05 3.86E-05 2.18E-05 1.09E-02
91 9.09E-03 1.36E-03 5.06E-04 2.12E-04 9.67E-05 4.93E-05 1.13E-02
121 1.07E-02 2.24E-03 8.99E-04 3.90E-04 1.84E-04 1.44E-02
151
1.19E-02 3.15E-03 1.40E-03 6.55E-04 1.71E-02
181
1.26E-02 3.87E-03 1.89E-03 1.84E-02
211
1.29E-02 4.38E-03 1.73E-02
241
1.31E-02 1.31E-02
0
Table C10
Radiation Doses to the Embryo/Fetus from 1 jiCi of 90Sr (in Equilibrium with 90Y)
Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (da: s) Cumulated Introduction 0-30 31-60 61-90 Dose
91-120 121-150 151-180 .181-210 211-240 241-270 0-270
0 9.07E-03 2.01E-03 1.57E-03 1.1OE-03 8.07E-04 6.58E-04 5.81E-04 5.15E-04 4.43E-04 1.68E-02
31 1.13E-02 2.04E-03 1.57E-03 1.09E-03 7.99E-04 6.49E-04 5.69E-04 5.00E-04 1.85E-02
61 2.03E-02 3.60E-03 1.72E-03 1.33E-03 8.94E-04 7.10E-04 6.04E-04 2.92E-02
91 1.50E-02 3.31E-03 2.80E-03 1.67E-03 1.17E-03 8.98E-04 2.48E-02
121 1.90E-02 7.93E-03 4.71E-03 3.11E-03 2.22E-03 3.70E-02
151
2.69E-02 1.1OE-02 7.41E-03 5.23E-03 5.05E-02
181
2.86E-02 1.36E-02 1.00E-02 5.22E-02
211
241 2.95E-02 1.54E-02 4.49E-02
2.93E-02 2.93E-02
Table Cl1 Radiation Doses to the Embryo/Fetus from 1 giCi of 106Ru (in Equilibrium with
106Rh) Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (da3ys) Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 1.56E-03 1.OOE-03 9.36E-04 7.68E-04 6.67E-04 5.94E-04 5.35E-04 4.85E-04 4.41E-04 6.99E-03
31 2.02E-03 1.21E-03 9.48E-04 7.77E-04 6.72E-04 5.94E-04 5.32E-04 4.80E-04 7.23E-03
61 2.42E-03 1.23E-03 9.56E-04 7.80E-04 6.70E-04 5.90E-04 5.27E-04 7.17E-03
91 2.50E-03 1.24E-03 9.68E-04 7.84E-04 6.68E-04 5.85E-04 6.74E-03
121 2.53E-03 1.25E-03 9.63E-04 7.77E-04 6.62E-04 6.18E-03
151 2.551E-03 1.26E-03 9.59E-04 7.69E-04 5.54E-03
181 2.55E-03 1.25E-03 9.55E-04 4.75E-03
211 2.54E-03 1.23E-03 3.77E-03
241 2.53E-03 2.53E-03
0 Table C12 Radiation Doses to the Embryo/Fetus from 1 giCi of 1251 Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-2 )40 241-270 0-270
0 2.081E-05 1.12E-05 7.34E-06 1.34E-05 1.46E-05 6.07E-06 4.65E-06 3.01E-06 2.07E-06 8.31E-05
31 2.72E-05 1.05E-05 1.27E-05 1.40E-05 1.04E-05 7.27E-06 4.83E-06 3.31E-06 9.02E-05
61 2.74E-05 1.70E-05 2.23E-05 1.63E-05 1. 15E-05 7.66E-06 5.28E-06 1.07E-04
91 1.64E-04 5.21E-05 3.23E-05 2.05E-05 1.31E-05 8.84E-06 2.91E-04
121 8.79E-04 2.88E-04 1.22E-04 5.70E-05 3.05E-05 1.38E-03
151 7.81E-04 3.12E-04 1.40E-04 7.08E-05 1.30E-03
181 6.78E-04 2.99E-04 1.48E-04 1. 12E-03
211 5.97E-04 2.98E-04 8.95E-04
241 5.33E-04 5.33E-04
Table C13 Radiation Doses to the Embryo/Fetus from 1 giCi of 1311 Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction 0-30 Dose
31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 5.93E-05 2.58E-06 1.88E-07 2.20E-08 3.39E-09 2.1OE-10 2.29E-1 1 1.32E-12 6.35E-14 6.21E-05
31 9.73E-05 2.31E-06 3.38E-07 5.05E-08 3.22E-09 3.47E-10 2.01E-11 9.66E-13 1.00E-04
61 9.44E-05 4.14E-06 7.60E-07 4.75E-08 5.23E-09 3.02E-10 1.46E-11 9.94E-05
91 6.52E-04 2. 11E-05 9.30E-07 9.12E-08 5.01E-09 2.33E-10 6.74E-04
121 3.54E-03 8.90E-05 6.03E-06 2.33E-07 7.82E-09 3.64E-03
151 2.35E-03 1.49E-04 5.56E-06 1.75E-07 2.50E-03
181
2.88E-03 1.15E-04 3.48E-06 3.OOE-03
211
241 1.98E-03 6.80E-05 2.05E-03
1.00E-03 1.OOE-03 (I
Table C14 Radiation Doses to the Embryo/Fetus from 1 4Ci of 1321 Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (day Cumulated Introduction 0-30 31-60 ys) Dose
61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 8.43E-05 .0 0 0 0 0 0 0 0 8.43E-05
31 1.06E-04 0 0 0 0 0 0 0 1.06E-04
61 1.27E-04 0 0 0 0 0 0 1.27E-04
91 1.30E-04 0 0
0 0 0 1.30E-04
121 1,51E-04 0 0 0 0 1.51E-04
151 1.53E-04 0 0 0 1.53E-04
181
1.56E-04 0 0 1.56E-04
211
1.56E-04 0 1.56E-04
241
1.56E-04 1.56E-04
Table C15 Radiation Doses to the Embryo/Fetus from 1 pCi of 1331 Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods Cumulated (days)
Introduction Dose
0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 2.81E-04 0 0 0 0 0 0 0 0 2.81E-04
31 5.32E-04 0 0 0 0 0 0 0 5.32E-04
61 6.85E-04 0 0 0 0 0 0 6.85E-04
91 7.04E-04 0 0 0 0 0 7.04E-04
121 9.04E-04 0 0 0 0 9.04E-04
151 8.59E-04 0 0 0 8.59E-04
181 8.49E-04 0 0 8.49E-04
211 8. 27E-04 0 8.27E-04
241 8.11E-04 8.11E-04 C)
Table. C16 Radiation Doses to the Embryo/Fetus from 1 gCi of 1341 Introduced into the Maternal Transfer Compartment (Blood)
Days of
- Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-2 40 241-270 0-270
0 2.22E-05 0 0 0 0 0 0 0 0 2.22E-05
31 2.79E-05 0 0 0 0 0 0 0 2.79E-05
61 3.44E-0S 0 0 0 0 0 0 3.44E-05
91 3.50E-05 0 0 0 0 0 3.50E-05
121 81E-05 0 0 0 0 3.8 IE-05
151 3.91E-05 0 0 0 3.91E-05
181 4.03E-05 0 0 4.03E-05
211 4.83E-05 0 4.83E-05
241 4.06E-05 4.06E-05
Table C17 Radiation Doses to the Embryo/Fetus from 1 gCi of lms Introduced into the Maternal Transfer Compartment (Blood)
Days of Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (dayys) Cumulated Gestation at Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 1.95E-04 0 0 0 0 0 0 0 0 1.95E-04
31 2.63E-04 0 0 0 0 0 0 0 2.63E-04
61 3.07E-04 0 0 0 0 0 0 3.07E-04
91 3.04E-04 0 0 0 0 0 3.04E-04
121 3.65E-04 03.66E-04 00 00 0 3.65E-04
151 0 3.66E-04
181 3.72E-04 0 0 3.72E-04
211 3.69E-04 0 3.69E-04
241 3.70E-04 3.70E-04 C>
Table C18 Radiation Doses to the Embryo/Fetus from 1 giCi of 134Cs Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (dayys)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 2.55E-02 2.15E-02 1.69E-02 1.33E-02 1.05E-02 8.29E-03 6.35E-03 4.37E-03 2.81E-03 1.10E-01
31 2.82E-02 2.23E-02 1.75E-02 1.38E-02 1.09E-02 8.38E-03 5.75E-03 3.71E-03 1.11E-01
61 2.92E-02 2.30E-02 1.82E-02 1.44E-02 1.10E-02 7.59E-03 4.88E-03 1.08E-01
91 3.03E-02 2.40E-02 1.89E-02 1.45E-02 9.98E-03 6.43E-03 1.04E-01
121 3.16E-02 2.49E-02 1.91E-02 1.31E-02 8.46E-03 9.72E-02
151 3.28E-02 2.5 1E-02 1.73E-02 1. 12E-02 8.64E-02
181 3.30E-02 2.28E-02 1.46E-02 7.04E-02
211 3.14E-02 2.03E-02 5.17E-02
241 3.24E-02 3.24E-02
Table C19 Radiation Doses to the Embryo/Fetus from 1 gCi of 137Cs Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 1.18E-02 1.13E-02 9.13E-03 7.36E-03 5.91E-03 4.74E-03 3.70E-03 2.60E-03 1.71E-03 5.83E-02
31 1.43E-02 1.17E-02 9.43E-03 7.59E-03 6.08E-03 4.74E-03 3.33E-03 2.19E-03 5.94E-02
61 1.501E-02 1.21E-02 9.72E-03 7.80E-03 6.09E-03 4.27E-03 2.81E-03 5.78E-02
91 1.55E-02 1.25E-02 1.OOE-02 7.79E-03 5.48E-03 3.60E-03 5.49E-02
121 1.60E-02 1.29E-02 1.00E-02 7.02E-03 4.63E-03 5.05E-02
151 1.65E-02 1.29E-02 9.05E-03 5.96E-03 4.44E-02
181 1.65E-02 1.16E-02 7.60E-03 3.57E-02
211 1.56E-02 1.03E-02 2.59E-02
241 1. 60E-02 1.60E-02 Table C20
CT3 Radiation Doses to the Embryo/Fetus from 1 gCi of 2MU
Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestatiorn Periods (days) Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 N* N N N N N N N N N
31 1.41E-03 2.31E-05 5.30E-06 1.19E-06 5.01E-07 2.71E-07 1.74E-07 1.24E-07 1.44E-03
61 4.30E-03 7.86E-04 1.89E-04 7.84E-05 4.25E-05 2.72E-05 1.94E-05 5.44E-03
91 6.29E-03 1.52E-03 6.29E-04 3.42E-04 2.19E-04 1.566E-04 9.16E-03
121 8.1OE-03 3.25E-03 1.78E-03 1.13E-03 8.09E-04 1.51E-02
151 9.51E-03 5.11E-03 3.28E-03 2.34E-03 2.02E-02
181 1.40E-02 8.88E-03 6.36E-03 2.92E-02
211 1.49E-02 1.06E-02 2.55E-02
241 2.38E-02 2.38E-02
- N indicates that the metabolic pattern is such that the dose rates and doses would be negligible throughout gestation when activity is administered immediately after fertilization. Approximations of doses resulting from administration during the first month are described on page C-1.
Table C21 Radiation Doses to the Embryo/Fetus from 1 4Ci of 234U
Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction 0-30 31-60 61-90 91-120 121-150 151-180 Dose
181-210 211-240 241-270 0-270
0 N* N N N N N N N N
31 N
1.40E-03 2.30E-05 5.26E-06 1. 18E-06 5.OOE-07 2.70E-07 1.73E-07
61 1.23E-07 1.43E-03
4.27E-03 7.82E-04 1.87E-04 7.79E-05 4.22E-05 2.70E-05 1.93E-05 5.41E-03
91 6.25E-03 1.51E-03 6.28E-04 3.39E-04 2.17E-04 1.55E-04 9.1OE-03
121 8.05E-03 3.23E-03 1.77E-03 1.13E-03 8.07E-04 1.50E-02
151
9.46E-03 5.07E-03 3.26E-03 2.32E-03 2.01E-02
181
1.40E-02 8.88E-03 6.34E-03 2.92E-02
211
1.48E-02 1.05E-02 2.53E-02
241
2.36E-02 2.36E-02 Table C22 I-
Radiation Doses to the Embryo/Fetus from 1 gCi of 235U
Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction 0-30 Dose
31-60 61-90 91-120 121-150 151-180 181-210 211-240 241-270 0-270
0 N* N N
N N N N N
31 N N
1.29E-03 2.11E-05 4.84E-06 1.09E-06 4.60E-07 2.48E-07 1.59E-07 1.13E-07 1.32E-03
61 3.93E-03 7.19E-04 1.73E-04 7.18E-05 3.88E-05 2.49E-05 1.77E-05 4.98E-03
91 5.75E-03 1.39E-03 5.78E-04 3.12E-04 2.OOE-04 1.43E-04 8.37E-03
121 7.40E-03 2.97E-03 1.62E-03 1.04E-03 7.41E-04 1.38E-02
151 8.70E-03 4.67E-03 3.OOE-03 2.14E-03 1.85E-02
181
1.28E-02 8.12E-03 5.82E-03 2.67E-02
211
1.36E-02 9.69E-03 2.33E-02
241
2.17E-02 2.17E-02
- N indicates that the metabolic pattern is such that the dose rates and doses would be negligible throughout gestation when activity is administered immediately after fertilization. Approximations of doses resulting from administration during the first month are described on page C-1.
r-
Table C23 Radiation Doses to the Embryo/Fetus from 1 pCi of 238U
Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-1 240 241-270 0-270
0 N* N N N N N N N N N
31 1.23E-03 2.01E-05 4.59E-06 1.04E-06 4.38E-07 2.36E-07 1.51E-07 1.08E-07 1.26E-03
61 3.75E-03 6,86E-04 1.64E-04 6.83E-05 3.70E-05 2.37E-05 1.69E-05 4.75E-03
91 5.49E-03 1.32E-03 5.49E-04 2.98E-04 1.90E-04 1.36E-04 7.98E-03
121 7.06E-03 2.83E-03 1.55E-03 9.9 1E-04 7.08E-04 1.31E-02
151 8.30E-03 4.45E-03 2.86E-03 2.04E-03 1.77E-02
181 1.22E-02 7.76E-03 5.54E-03 2.55E-02
211 1.30E-02 9.23E-03 2.22E-02
241 2.07E-02 2.07E-02 Table C24 C- Radiation Doses to the Embryo/Fetus from 1 gCi of 238Pu.
Introduced into the Maternal Transfer Compartment (Blood)
Days of Cumulated Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days)
Dose Introduction 0-30 31-60 61-90 91-120 121-150 151-180 181-210 211-2 40 241-270 0-270
0 N* N N N N N N N N N
31 2.68E-03 4.38E-05 1.00E-05 2.26E-06 9.55E-07 5.14E-07 3.30E-07 2.35E-07 2.74E-03
61 8.19E-03 1.50E-03 3.58E-04 1.49E-04 8.05E-05 5.16E-05 3.67E-05 1.04E-02
91 1.20E-02 2.89E-03 1.20E-03 6.50E-04 4.15E-04 2.96E-04 1.75E-02
121 1.54E-02 6.18E-03 3.37E-03 2.15E-03 1.54E-03 2.86E-02
151 1.81E-02 9.70E-03 6.24E-03 4.43E-03 3.85E-02
181 2.66E-02 1.69E-02 1.21E-02 5.56E-02
211 2.84E-02 2.01E-02 4.85E-02
241 4.51E-02 4.51E-02
- N indicates that the metabolic pattern is such that the dose rates and doses would be negligible throughout gestation when activity is administered immediately after fertilization. Approximations of doses resulting from administration during the first month are described on page C-1.
Table C25 Radiation Doses to the Embryo/Fetus from 1 piCi of 239Pu Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus During Indicated Gestation Periods (days) Cumulated Introduction 0-30 31-60 61-90 91-120 121-150 151-180 Dose
1.81-210 211-240 241-270 0-270
0 N N N N N N N N N
31 2.52E-03 4.12E-05 9.40E-06 2.12E-06 8.97E-07
61 4.83E-07 3. 1OE-07 2.21E-07 2.57E-03
7.68E-03 1.40E-03 3.36E-04 1.40E-04 7.56E-05 4.85E-05
91 3.46E-05 9.71E-03
1. 12E-02 2.71E-03 1.12E-03 6.07E-04 3.90E-04 2.78E-04
121 1.63E-02
1.45E-02 5.80E-03 3.17E-03 2.02E-03 1.44E-03 2.69E-02
151
1.70E-02 9.09E-03 5.85E-03 4.17E-03 3.61E-02
181
2.50E-02 1.59E-02 1.13E-02 5.22E-02
211
241 2.66E-02 1.88E-02 4.54E-02
4.23E-02 4.23E-02
03 Table C26 Radiation Doses to the Embryo/Fetus from 1 jiCi of 241Am Introduced into the Maternal Transfer Compartment (Blood)
Days of Gestation at Dose (rad) to Embryo/Fetus Indicated Gestation Periods (days) Cumulated Introduction 0-30 31-60 61-90 Dose
91-120 50 151-180 181-210 211-240 241-270 0-270
0 N* N N N N N N N N N
31 5.36E-04 8.76E-06 2.OOE-06 4.52E-07 1.91E-07 1.03E-07 6.60E-08 4.71E-08 5.48E-04
61 1.64E-03 2.99E-04 7.16E-05 2.97E-05 1.61E-05 1.03E-05 7.35E-06 2.07E-03
91 2.39E-03 5.76E-04 2.39E-04 1.30E-04 8.30E-05 5.92E-05 3.48E-03
121 3.08E-03 1.23E-03 6.75E-04 4.31E-04 3.08E-04 5.72E-03
151 3.61E-03 1.94E-03 1.24E-03 8.89E-04 7.68E-03
181
5.32E-03 3.38E-03 2.41E-03 1.11E-02
211
241 5.67E-03 4.02E-03 9.69E-03
9.04E-03 9.04E-03
- N indicates that the metabolic pattern Is such that the dose rates and doses would be negligible fertilization. Approximations o doses resulting throughout gestation when activity is administered immediately after from administration during the first month are described on page C-1.
REFERENCES
C1. M. R. Sikov et al., "Contribution of Maternal C2. International Commission on Radiological Pro Radionuclide Burdens to Prenatal Radiation tection, "Limits for Intakes of Radionuclides by Dose-Interim Recommendations," NUREG/ Workers," ICRP No. 30, Parts 1 through 4, CR-5631, Revision I (PNL-7445), U.S. Nu including supplements, Annals of the ICRP,
clear Regulatory Commission, March 1992. Volume 2, No. 3/4, Pergamon Press Inc., 1979.
C-15
APPENDIX D
EXAMPLES OF EMBRYO/FETUS DOSE CALCULATIONS
The purpose of this appendix is to present exam appropriate transfer fraction. The second step in ples of the methods of the guide for calculating the volves the determination of the embryo/fetus dose dose equivalent to the embryo/fetus. The examples based on the maternal radionuclide blood content.
have been developed to demonstrate the calculational methods; the methods for evaluating and determining Six example calculations are provide
d. Cases I
maternal exposures, body burdens, and intakes are and 2 address ingestion intakes by the declared preg not included. These examples are not intended to de nant woman. Cases 3 and 4 address inhalation in scribe all the measures that would be required for de takes. Case 5 evaluates a pre-existing body burden termining the maternal exposure. Instead, the exam and determines the embryo/fetus dose equivalent ples are presented to concisely demonstrate the cal based on the maternal burden existing at time of pregnancy. Case 6 presents an example of summing culational methods once data on maternal exposure external and internal doses and instituting worker have been obtained. It is important to keep in mind that an evaluation is no better than the quality of the controls to ensure the dose limit is not exceeded.
data. In applying the methods of this guide, a primary The two methods in the guide for calculating the concern has to be the reliability of the maternal expo embryo/fetus dose equivalent are presented: the sim sure data. The calculation of the embryo/fetus dose plified method as presented in the regulatory position consists of a two-step process. First, the content of a in Section 2 of this guide and the Revision 1 to radionuclide in maternal blood has to be determined. NUREG/CR-5631 gestation-time dependent method This is accomplished by multiplying the intake by the as presented in the regulatory position in Section 3.
D-1
CASE 1 EMBRYO/FETUS DOSE FOLLOWING ACUTE INGESTION
INTAKE BY DECLARED PREGNANT WOMAN
1.1 Exposure Scenario
1.3.1 Simplified Method A declared pregnant woman unknowingly ingests a substance that contains trace amounts of 58Co. The The regulatory position in Section 2 of the guide licensee determines that the woman ingested 22 gCi presents the Simplified Method for calculating the of S8Co over a 4-day period.* The intake is confined embryo/fetus dose equivalent. From Appendix A to to a short time period (relative to the effective bio the guide, the 58 Co dose equivalent factor is logical retention half-life of 5 8Co) within the first 9.17E-03 rem/gCi (in blood). The dose equivalent is month of the pregnancy. Because the intake is as calculated using Equation 1 from the regulatory posi sumed to have occurred within a single 30-day gesta tion in Section 2.5 of the guide. Substituting the val tion period interval (i.e., a 30-day period as used for ues for intake, the gut-to-blood transfer factor (fl)
calculating intakes and doses), the ingestion may be and dose factor into this equation yields the following dose equivalent calculation:
treated as a single, acute intake.
1.2 Determining Blood Uptake Dose Equivalent = Intake x f, x Dose Factor
= 22 p-Ci x 0.3 x 9.17E-03 The calculation of the dose to the embryo/fetus is rem/p.Ci based on the amount of the intake that is available for = 0.061 rem uptake within the first transfer compartment (i.e.,
blood). Applying the guidance of the regulatory posi 1.3.2 Method Using Revision 1 to tion in Section 2.2 of the guide, the blood uptake for NUREG/CR-5631 an ingestion intake may be calculated by multiplying the intake by the gut-to-blood transfer factor (fl): The regulatory position specified in Section 3 of the guide presents the method for calculating the em Blood Uptake = f, x Ingestion Intake bryo/fetus dose using the gestation-time dependent methodology of Revision 1 to NUREG/CR-5631. Ta For cobalt, the f, value from Appendix B to the ble C5 of Appendix C to the guide presents the gesta guide is 0.3. For this example, the predetermined in tion-time dependent dose factors for 5 8Co. From this gestion intake is 22 p.Ci. Inserting these values into table, the column under the heading "Cumulated the above equation results in the following calculation Dose" presents the dose to the embryo/fetus for the of the maternal blood content: remainder of the gestation period resulting from the introduction of unit activity (i.e., 1 gCi) into the Blood Uptake = 0.3 x 22 pCi = 6.6 gCi blood of the woman at the beginning of the specified monthly gestation period interva
l. The cumulated
1.3 Calculating the Embryo/Fetus Dose dose factor for a SSCo intake during the first month of gestation is 8.79E-03 rads per microcurie in maternal Equivalent blood. The regulatory position specified in Section The calculation of the embryo/fetus dose equiva 3.2.2 of the guide states that it should be assumed lent is based on the activity uptake into the first trans that all intakes occurring within any of the 30-day fer compartment (i.e., maternal blood). First, the time periods of gestation occur at the beginning of dose will be calculated using the Simplified Method as that period. As discussed in the regulatory position in presented in the regulatory position specified in Sec Section 3.2.1, a radiation quality factor of 1.0 should tion 2 of the guide. Next, the gestation-time depend be used for -SCo in converting from an absorbed dose ent method for calculating the dose equivalent will be in rads to an equivalent dose expressed as rems.
presented. Applying the method of the regulatory position speci fied in Section 3.2, the dose equivalent to the em bryo/fetus is calculated as follows:
Dose Equivalent = Intake x f, x Dose Factor x
- Acceptable methods for determining intake using bioassay 1.0 rem/rad measurements are presented in Proposed Revision 1 to Regu latory Guide 8.9 (DG-8009), "Interpretation of Bioassay = 22 ItCi x 0.3 x 8.79E-03 rad/
Measurements." jiCi x 1.0 rem/rad
= 0.058 rem D-2
CASE 2 EMBRYO/FETUS DOSE FOLLOWING CHRONIC INGESTION
INTAKE BY DECLARED PREGNANT WOMAN
2.1 Exposure Scenario from Appendix A is 5.87E-05 rem per microcurie in Over an extended period of time, a declared maternal blood. The dose contribution to the em pregnant woman unknowingly consumes water that bryo/fetus for each monthly intake may be calculated contains low levels of tritium contamination. The li as follows:
censee discovers the tritium contaminated water in the third month of the woman's pregnancy. A thor Dose Equivalent = Intake x f, x Dose Factor ough evaluation of the situation and associated per First-month intake sonnel exposures is conducted, including bioassay measurements and contaminated water sample analy 156 jiCi x 1.0 x 5.87E-05 rem/liCi = 0.009 rem sis. It is determined that the source did not exist prior Second-month intake to the woman's pregnancy. In keeping with the regu latory positions specified in Sections 2.7 and 3.3 of 248 jiCi x 1.0 x 5.87E-05 rem/ltCi = 0.015 rem the guide, multiple intakes should be evaluated on at least a 30-day frequency. The licensee determines Third-month intake that the declared pregnant woman ingested the fol 185 j+/-Ci x 1.0 x 5.87E-05 rem/gCi = 0.011 rem lowing amounts of tritium over the 3-month period:
TOTAL = 0.035 rem
2.3.2 Method Using Revision 1 to Stage of Gestation at Intake NUREG/CR-5631 Time of Intake (ACi)
(days) Using the methods of Revision 1 to NUREG/
CR-5631, the dose to the embryo/fetus is calculated
0 - 30 156 in a manner similar to that of the Simplified Method,
31 - 60 as presented above. However, as discussed in the
248 regulatory position specified in Section 3.2.1, the
61 - 90 185 dose factor should be taken from Appendix C for the time period representing the time of intake relative to stage of gestation. Table C1 in Appendix C presents the 3H dose factors. The first column of Table C1
2.2 Determining Blood Uptake presents the gestation time (e.g., 0, 30, 60 days), and The amount of tritium that is available for uptake the last column presents the cumulated dose to the by the blood is calculated by multiplying the intake by embryo/fetus for the remainder of the gestation pe the f, value for the radionuclide. For tritium, the riod following the introduction of unit activity into value of f, is 1.0 (refer to the hydrogen entry in Ap maternal blood at the specified gestation time. As pendix B to this guide). Therefore, the amount of specified in the regulatory position in Section 3.2.2 of tritium that is absorbed into the blood (as evaluated the guide, an intake at any time within a specific for calculating the embryo/fetus dose) is the same as monthly gestation period (i.e., a 30-day period) may the intake quantities presented above. be assumed to have occurred at the beginning of the monthly period for the purpose of determining the
2.3 Calculating Embryo/Fetus Dose Equivalent appropriate dose factor to be used. For example, for intakes occurring during the first month of pregnancy,
2.3.1 Simplified Method the dose factor under the "Cumulated Dose" column corresponding to 0 days of gestation (as designated in Equation 1 from the regulatory position specified the left-most column of the table) should be used.
in Section 2.5 of the guide may be used for calculat Cumulated dose factors taken from Table C1 for in ing the dose equivalent for the entire gestation period takes in the respective months of gestation are pre from each monthly intake. The tritium dose factor sented below:
Stage of Gestation at Cumulated Dose Factor for Time of Intake Remainder of Gestation Period (rad/gCi, blood)
1st Month (0 - 30 days) 9.03E-06
2nd Month (31 - 60 days) 1.77E-05
3rd Month (61 - 90 days) 4.02E-05 D-3
Using these gestation-time dependent dose fac Second-month intake tors, the dose equivalent to the embryo/fetus is calcu lated using the regulatory position specified in Section 248 gCi x 1.0 x 1.77E-05 rad/4Ci x
3.2 of the guide. The radiation quality factor for 3H is 1.0 rem/rad = 0.004 rem
1.0. The dose to the embryo/fetus for the remainder Third-month intake of the gestation period resulting from intakes occur ring within each month is calculated as follows: 185 gCi x 1.0 x 4.02E-05 rad/gCi x
1.0 rem/rad = 0.007 rem Dose Equivalent = Intake x f, x DFi TOTAL = 0.013 remi*
First-month intake *The difference between the sum of the monthly doses and the total (i.e., 0.012 rem versus 0.013 rem) is caused by round
156 gCi x 1.0 x 9.03E-06 rad/gCi x ing. In keeping with the recommendation contained in the Discussion section of this guide, final results should be
1.0 remlrad = 0.001 rem rounded to the nearest thousandth of a rem.
D-4
CASE 3 EMBRYO/FETUS DOSE FOLLOWING ACUTE INHALATION INTAKE
BY DECLARED PREGNANT WOMAN
3.1 Exposure Scenario Blood Uptake = TFi x Inhalation Intake During the performance of a medical administra = 0.63 x 100 gCi tion, a woman worker accidentally receives a single, acute inhalation intake of 100 gCi of 1311. At the time = 63 gxCi of the exposure, the woman was in the third month of
3.3 Calculating Embryo/Fetus Dose Equivalent pregnancy but had not declared her pregnancy to her employer (the licensee). Shortly thereafter, she de 3.3.1 Simplified Method clares her pregnancy in writing.
For this example, the predetermined inhalation
3.2 Determining Blood Uptake intake is 100 gzCi. From Appendix A to the guide, the dose factor for 1311 is 3.64E-03 rem/gCi (in blood).
The calculation of the dose to the embryo/fetus is The dose equivalent to the embryo/fetus may be cal based on the amount of the intake that is available for culated using Equation 2 from the regulatory position uptake within the first transfer compartment (i.e., specified in Section 2.5 of the guide:
blood). Also, the transfer to the blood is a function of the lung clearance class. The lung clearance class for Dose Equivalent = Ii x TFi x DFi all chemical compounds of iodine is Class D, denoting = 100 gCi x 0.63 x 3.64E-03 a 0- to 10-day lung clearance half-life. (Appendix B rem/! Ci to 10 CFR 20.1001-20.2401 provides the lung clear = 0.229 rem ance classes for the different chemical compounds of the specified radionuclides.) Applying the guidance of 3.3.2 Method Using Revision 1 to the regulatory positions specified in Sections 2.3 and NUREG/CR-5631
2.4 of the guide, the transfer fraction of inhaled activ ity to the blood for a Class D radionuclide may be The regulatory position specified in Section 3 of calculated as follows: the guide presents the method for calculating the em bryo/fetus dose using the methodology of Revision 1 to NUREG/CR-5631. The inhalation intake is deter TFi (Class D) = 0.48 + 0.15 x flj mined to have occurred during the third month of the gestation period. Table C13 of Appendix C to the where: guide presents the gestation-time dependent dose fac tors for 1311. In this table, the left-most column speci fies the beginning time for each monthly gestation TFi = transfer fraction of inhaled activity to the period (e.g., 0 for 0-30 days, 31 for 31-60 days).
first transfer compartment (blood) The right-most column presents the corresponding cumulated dose to the embryo/fetus for the remain der of the gestation period for unit activity introduced fl,i gut-to-blood transfer factor forradionuclide i (from Appendix B to the guide) into the maternal blood. From this table, the cumu lated dose factor for an 1311 intake during the third
0.48 = fraction of inhalation intake that is cleared month of gestation is 9.94E-05 rad/p.Ci uptake into directly from the lung to the blood for Class blood. As discussed in the regulatory position speci D compounds fied in Section 3.2.1, a radiation quality factor of 1.0
should be used for 1311. Applying the methods of the
0.15 = fraction of inhaled radionuclide that is regulatory position specified in Section 3.2, the dose cleared from the lung to the GI tract for equivalent to the embryo/fetus may be calculated.
Class D compounds The value for the transfer fraction (TFi) is the same as calculated above (i.e., 0.63). Using these parame For iodine, the f, value from Appendix B to the ter values along with Equation 2 from the guide, the guide is 1.0. Inserting these values into the above embryo/fetus dose is calculated as follows:
equation results in the following calculation of the transfer fraction:
Dose Equivalent = Ii x TFi x DFi x 1.0
rem/rad
= 100 Ci x 0.63 x 9.94E-05 TFi = 0.48 + 0.15 x 1.0 rad/p.Ci x 1.0 rem/rad
= 0.63 = 0.006 rem The resultant blood uptake may be calculated by multiplying the transfer fraction by the total intake: This example illustrates the difference that can occur by using the gestation-time dependent dose D-5
factors for the calculation of the embryo/fetus dose equivalent. The Simplified Method, as presented of iodine by the embryo; the thyroid has not yet de above, for this example yields an embryo/fetus dose veloped. It is not until approximately the beginning of of 0.229 rem; using the gestation-time dependent the fourth month of the gestation period that the fetal dose factors results in a calculated embryo/fetus dose thyroid develops to a point that thyroid iodine uptake equivalent of 0.006 rem-a factor of almost 40 less. is thought to occur. Therefore, any maternal intakes This difference reflects the fact that during early em during the second and third trimesters will result in a bryonic development there is no preferential uptake significantly larger dose to the embryo/fetus than will result from the same intake during the first trimester.
D-6
CASE 4 EMBRYO/FETUS DOSE FOR CHRONIC INHALATION INTAKE
BY DECLARED PREGNANT WOMAN
4.1 Exposure Scenario of a mixture of 30% Class D and 70% Class Y com During the third through fifth month of her preg pounds. In keeping with the regulatory positions nancy, a declared pregnant woman is exposed to air specified in Sections 2.7 and 3.3 of the guide, intakes borne levels 9 f 23U. Extensive air sampling and fol over an extended time should be evaluated on at least lowup bioassay measurements are conducted to a 30-day frequency. The licensee determines that the closely monitor the woman's intake. From these woman inhaled the following amounts of 238 U over measurements, it is determined that the mU consists the 3-month period:
Stage of Gestation at Class D Intake Class Y Intake Time of Intake (p.Ci) (.Ci)
(days)
61 - 90 0.038 0.089
91 - 120 0.061 0.14
121 - 150 0.15 0.35
4.2 Determining Blood Uptake The resultant total blood uptake is calculated. by multiplying the TFi value by the inhalation intake:
The calculation of the dose to the embryo/fetus is based on the amount of intake that is available for uptake within the first transfer compartment (i.e., Blood Uptake = TFi x Inhalation Intake blood). Also, the transfer to the blood is a function of
"he lung clearance class. Applying the guidance of the For a Class Y compound, the transfer fraction is egulatory positions specified in Sections 2.3 and 2.4 calculated as follows:
of the guide, the transfer fraction (TFi) of inhaled activity to the first transfer compartment for a Class D
compound may be calculated as follows:
TFi (Class Y) = 0.05 + 0.58 x fjj where:
TFi (Class D) = 0.48 + 0.15 x fli where: 0.05 = fraction of inhalation intake that is cleared directly from the lung to the blood for Class Y compounds TFi = transfer fraction of inhaled activity to the 0.58 = fraction of inhaled radionuclide that is first transfer compartment cleared from the lung to the GI tract for Class Y compounds f1 i gut-to-blood transfer factor for radionuclide i (from Appendix B to the guide). The total blood uptake can be calculated in the same manner as discussed above for the Class D com
0.48 = fraction of inhalation intake that is cleared pound.
directly from the lung to the blood for Class D compounds For uranium, the f, value from Appendix B to the guide is 0.05. Applying the above equations, the
0.15 = fraction of inhaled radionuclide that is amounts of m2U transferred to the blood as a func cleared from the lung to the GI tract for tion of gestation period are presented in the following Class D compounds table:
D-7
Transfer Fraction and Transfer Fraction and Blood Uptake Blood Uptake Stage of Gestation at (Class D) (Class Y)
Time of Intake Transfer Blood Transfer Blood (days) Fraction Uptake Fraction Uptake (TFi) (AiCi) (TFi) (xCi)
61 - 90 0.49 0.0186 0.079 0.00703
91 - 120 0.49 0.0299 0.079 0.0111
121 - 150 0.49 0.0735 0.079 0.0276
4.3 Calculating Embryo/Fetus Dose Equivalent Class Y Inhalation Intake
4.3.1 Simplified Method The dose to the embryo/fetus is calculated by us Dose Equivalent = Intake x TF1 x DFi ing Equation 2 from the regulatory position in Section
2.5 of the guide. From Appendix A, the dose factor Third-month intake for 238U is 5.10E-01 rem/4Ci (in blood). Applying this dose factor along with the monthly transfer frac tions (as calculated above) results in the following 0.089 pCi x 0.079 x 5.10E-01 rem/giCi dose calculations: = 0.004 rem Class D Inhalation Intake Fourth-month intake Dose Equivalent = Intake x TFi x DFi 0.14 jiCi x 0.079 x 5.10E-01 rem/4Ci
= 0.006 rem Third-month intake
0.038 gCi x 0.49 x 5.10E-01 rem/4Ci Fifth-month intake
= 0.009 rem Fourth-month intake 0.35 j+/-Ci x 0.079 x 5.10E-01 rem/liCi
= 0.014 rem
0.061 p.Ci x 0.49 x 5.10E-01 rem/p.Ci
= 0.015 rem TOTAL = 0.024 rem Fifth-month intake The dose to the embryo/fetus resulting from each
0.15 gCi x 0.49 x 5.10E-05 rem/jiCi single-month intake should be determined by adding
= 0.037 rem the Class D component with the Class Y component.
The total gestation period dose is the sum of the TOTAL = 0.061 rem cumulated dose resulting from each monthly intake.
Class D Dose Class Y Dose Total Dose Gestation Month (rem) (rem) (rem)
3rd Month (61 - 90 days) 0.009 0.004 0.013
4th Month (91 -120 days) 0.015 0.006 0.021
5th Month (121 -150 days) 0.037 0.014 0.051 TOTAL 0.085 rem
4.3.2 Method Using Revision 1 to in a manner similar to the Simplified Method above.
NUREG/CR-5631 However, as discussed in the regulatory position Using the methods of Revision 1 to NUREG/ specified in Section 3.2, the dose factor should be CR-5631, the dose to the embryo/fetus is calculated taken from Appendix C for the period representing D-8
the time of intake relative to stage of gestation. Table corresponding cumulated dose to the embryo/fetus C23 of Appendix C presents the gestation-time de for the remainder of the gestation period per unit ac pendent dose factors for 238U. In this table, the left tivity introduced into the maternal blood. From Table most column specifies the beginning time for each C23, the 238U cumulated dose factors for intakes in monthly gestation period (e.g., 0 for 0-30 days, 31 the respective month of gestation are presented be for 31-60 days). The right-most column presents the low:
Stage of Gestation at Cumulated Dose Factor for Remainder Time of Gestation Period of Intake (rad/gCi, blood)
3rd Month (61 - 90 days) 4.75E-03
4th Month (91 -120 days) 7.98E-03
5th Month (121 -150 days) 1.31E-02 Using these gestation-time dependent dose fac Class Y Inhalation Intake tors, the dose equivalent to the embryo/fetus is calcu lated using the regulatory position specified in Section Dose Equivalent = Intake x TF1 x DFi
3.2 of the guide. A radiation quality factor of 20 x 20 rem/rad should be used for MU as specified in the regulatory position in Section 3.2.1. The dose equivalent is cal Third-month intake culated on a monthly basis as follows:
Class D Inhalation Intake 0.089 RCi x 0.079 x 4.75E-03 rad/gCi x 20 rem/rad = 0.001 rem Dose Equivalent = Intake x TF1 x DFi Fourth-month intake x 20 rem/rad Third-month intake 0.14 gCi x 0.079 x 7.98E-03 rad/gCi x 20 rem/rad = 0.002 rem
0.038 gCi x 0.49 x 4.75E-03 rad/ixCi x 20 rem/rad = 0.002 rem Fifth-month intake Fourth-month intake 0.35 ACi x 0.079 x 1.31E-02 rad/;iCi x 20 rem/rad = 0.007 rem
0.061 jtCi x 0.49 x 7.98E-03 rad/LCi x 20 rem/rad = 0.005 rem TOTAL = 0.010 rem Fifth-month intake The dose to the embryo/fetus resulting from each
0.15 gCi x 0.49 x 1.31E-02 rad/tCi single-month intake should be determined by adding x 20 rem/rad = 0.019 rem the Class D component with the Class Y component.
The total gestation period dose is the sum of the TOTAL = 0.026 rem cumulated dose resulting from each monthly intake.
Class D Dose Class Y Dose Total Dose Gestation Month (rem) (rem) (rem)
3rd Month (61 - 90 days) 0.002 0.001 0.003
4th Month (91 -120 days) 0.005 0.002 0.007
5th Month (121 -150 days) 0.019 0.007 0.026 TOTAL 0.036 rem D-9
CASE 5 PRE-EXISTING MATERNAL BODY BURDEN AT TIME OF PREGNANCY
5.1 Exposure Scenario r ,.. I A.
va~-u pi W-existung rjurclefl)
x DFi A declared pregnant woman is determined to have an existing body burden of 137Cs at the time of = 2.8 jxCi x 5.94E-02 pregnancy. The burden is a result of an acute inhala rem/gCi tion intake that occurred around 2 months prior to = 0.166 rem the pregnancy. Extrapolating from bioassay measure ments, the body burden at the time of pregnancy is 5.4.2 Method Using Revision 1 to estimated to be 2.8 gCi. NUREG/CR-5631 Similar to the calculation above, the dose to the
5.2 Evaluating the 1% ALI Threshold embryo/fetus is calculated by multiplying the body burden existing at time of pregnancy by the appropri ate gestation-time dependent dose factor. Table C19 The regulatory position specified in Section 1.6 of Appendix C to this guide presents the gestation of the guide states that if a body burden existing at time dependent dose factors for ' 37Cs. In this table, time of pregnancy exceeds 1% of the stochastic ALI the left-most column specifies the beginning time for for the appropriate mode of intake (ingestion or inha each monthly gestation period (e.g., 0 for 0-30 days, lation), the dose to the embryo/fetus from this burden 31 for 31-60 days). The right-most column presents should be evaluated. From Appendix B to 10 CFR the corresponding cumulated dose to the embryo/fe
20.1001-20.2401, the inhalation* stochastic ALI tus for the remainder of the gestation period for unit value for 137Cs is 200 p.Ci (Column 2 entry under Ta activity introduced into the maternal blood. As stated ble 1 of the appendix). Since the existing burden of in the regulatory position specified in Section 3.2.3 of
2.8 jiCi is larger than 1% of this ALI value, the dose the guide, the uptake in the blood for burdens exist to the embryo/fetus should be evaluated. ing at time of pregnancy should be assumed to occur during the first month of pregnancy.
- From this table,
5.3 Determining Blood Uptake the cumulated dose factor for a 137 Cs intake during the first month of gestation is 5.83E-02 rad/4Ci up take into blood. As discussed in Section 3.2.1 of the
.The regulatory position specified in Section 2.6 guide, a radiation quality factor of 1.0 should be used of the guide states that the total burden determined to for 13 7Cs. The dose equivalent to the embryo/fetus is exist at the time of pregnancy should be assumed to calculated as follows:
be available for uptake in the blood of the woman.
Therefore, for this example, blood uptake should be assumed to be the same as the existing body burden Dose Equivalent = Ai (pre-existing burden)
of 2.8 p.Ci. x DFi x 1.0 rem/rad
= 2.8 gCi x 5.83E-02
5.4 Calculating the Embryo/Fetus rad/p.Ci x 1.0 rem/rad
= 0.163 rem Dose Equivalent
5.4.1 Simplified Method
- The regulatory position specified in Section 3.2.3 of the guide allows the use of time-dependent release kinetics for estimat With the assumption that the blood uptake ing the uptake in the maternal blood. This in-depth evaluation equates to the body burden existing at the time of may be warranted for unusual exposure situations; however, for this example, the simplifying assumption of total uptake pregnancy, the dose to the embryo/fetus is calculated during the first month will be used. Also, note that for certain simply by multiplying the burden by the radionuclide radionuclides a blood uptake at the beginning of the gestation period results in a negligible dose contribution to the embryo/
dose factor. From Appendix A to the guide, the dose fetus. For these radionuclides, per guidance of the regulatory factor for 137CS is 5.94E-02 rem/ACi (in blood); position specified in Section 3.2.3 and Appendix C, the cumu therefore, the dose is calculated as follows: lated dose value for the second month of the gestation period (i.e., the 31-day gestation time) should be used.
L
D-10
CASE 6 MATERNAL CHRONIC EXTERNAL EXPOSURE AND INHALATION INTAKE
.1 Exposure Scenario embryo/fetus become applicable. Once declared, past exposures incurred during the gestation period and During the processing of byproduct material any burdens existing at time of pregnancy should be specimens, a woman receives periodic exposure to evaluated.
airborne levels of 137Cs and 144Ce. The lung clearance class for all compounds of cesium is Class D; and for The licensee evaluates the dosimetry records for cerium the chemical compound is determined to be the declared pregnant woman, including air sample an oxide, thereby representing a "Y" lung clearance data and bioassay measurements. It is determined class. The woman becomes pregnant. However, she that at the time of pregnancy the woman had an exist does not inform her employer (the licensee) until the ing body burden of 1.14 gCi of 1
37 Cs and 0.12 p.Ci of third month of the gestation period. At this time, she 144Ce. Intakes during the first, second, and third becomes a declared pregnant woman and the more months of the gestation period are determined and restrictive dose limits of 10 CFR 20.1208 for the are presented in the following table:
Total Intake Stage of Gestation at (ACi)
37 1 Time of Intake 1 CS "Ce (days) (Class D) (Class Y)
Pre-Existing 1.14 0.12
0 - 30 0.48 0.078
31 - 60 0.76 0.14
61 - 90 0.23 0.093 The declared pregnant woman's external expo 6.2.2 Determining Blood Uptake sure is evaluated and is determined to be 0.285 rem from the time of pregnancy to the time of declaration. The regulatory position specified in Section 2.6 After declaration, the licensee imposes radiological of the guide states that the total burden determined to controls to ensure that additional exposures are kept exist at the time of pregnancy should be assumed to to a minimum, pending a thorough evaluation of the be available for uptake in the blood of the woman.
woman's exposures and the resultant embryo/fetus Therefore, for this example, blood uptake should be dose equivalent. assumed to be the same as the existing body burdens of 1.14 iCi of 137 Cs and 0.12 giCi of 144Ce.
6.2 Evaluating Embryo/Fetus Dose Equivalent
6.2.3 Calculating the Embryo/Fetus Dose from Pre-Existing Body Burden Equivalent from Pre-Existing Burden
6.2.1 Evaluating the 1% ALI Threshold Only the Simplified Method will be used in this example for calculating the embryo/fetus doses. For The regulatory position specified in Section 1.6 ' 37 Cs, the approach for using the gestation-time of the guide states that if a body burden existing at dependent method (Revision 1 to NUREG/CR-5631 time of pregnancy exceeds 1% of the stochastic ALI method) would be similar to the calculations pre for the appropriate mode of intake (ingestion or inha sented in Case 5, Section 5.4.2. For '44Ce, gekiation lation), the dose to the embryo/fetus from this burden time dependent dose factors have not been devel should be evaluated. From Appendix B to 10 CFR oped.
20.1001-20.2401, the inhalation stochastic ALI
value for 13 7Cs is 200 gtCi, and for Class Y 144Ce is 10 With the assumption that the blood uptake ptCi (Column 2 entry under Table 1 of the appendix). equates to the body burden existing at the time of Since the sum of the existing burdens of 1.14 p.Ci of pregnancy, the dose to the embryo/fetus is calculated
"-17Cs and 0.12 ptCi of 1'4Ce divided by their respec simply by multiplying the burden by the radionuclide e ALI values is larger than 0.01 (i.e., Y (bur dose factor. From Appendix A to the guide, the dose
,.eni -- ALIi ) > 0.01), the dose to the embryo/fetus factor for 13 7 Cs is 5.94E-02 rem/p.Ci (in blood) and resulting from the maternal pre-existing burden for 144Ce is 3.79E-0 1 rem/pLCi (in blood). The dose is should be evaluated. calculated as follows:
D-11
TFi (Class D) = 0.48 + 0.15 x fl,i Dose Equivalent = 7 Ai (pre-existing burden x DFi where:
= (1.14 gCi x 5.94E-02 rem/ACi) TFi = transfer fraction of inhaled activity to the
+ (0.12 gCi first transfer compartment x 3.79E-01 rem/gCi)
= 0.068 + 0.045 rem fij = gut-to-blood transfer factor for radionuclide
= 0.113 rem i (from Appendix B to this guide)
0.48 = fraction of inhalation intake that is cleared
6.3 Calculating the Embryo/Fetus Dose Equiv directly from the lung to the blood for Class alent from Intakes During Pregnancy D compounds
0.15 = fraction of inhaled radionuclide that is
6.3.1 Evaluating 1% ALI Threshold cleared from the lung to the GI tract for Class D compounds Based on the requirements of 10 CFR
The resultant total blood uptake is calculated by
20.1502(b) (2) and the regulatory position specified in Section 1.1 of this guide, the dose to the embryo/ multiplying the TFi value by the inhalation intake:
fetus is to be evaluated if intakes during the year by the declared pregnant woman are likely to exceed 1% Blood Uptake = TFi x Inhalation Intake of the stochastic ALIs. Without having to consider For a Class Y compound, the transfer fraction is other intakes by the woman during the year, the 1%
threshold is exceeded based on the intakes by the de calculated as follows:
clared pregnant woman during the first 3 months of the pregnancy. Therefore, an evaluation of the em TFi (Class Y) = 0.05 + 0.58 x flj bryo/fetus dose is required.
where:
With multiple intakes occurring during a single 0.05 = fraction of inhalation intake that is cleared monthly period, the intakes may be modeled as cu mulative intakes within each specified gestational monthly period.
directly from the lung to the blood for Class Y compounds
0.58 = fraction of inhaled radionuclide that is L
cleared from the lung to the GI tract for
6.3.2 Determining Blood Uptake Class Y compounds The calculation of the dose to the embryo/fetus is The total blood uptake can be Calculated in the based on the amount of the intake that is available for same manner as discussed above for the Class D com uptake within the first transfer compartment (i.e., pound.
blood). Also, the transfer to the blood is a function of the lung clearance class. Applying the guidance of the For cesium, the f, value from Appendix B to this regulatory positions specified in Sections 2.3 and 2.4, guide is 1.0; for cerium, the value is 3E-04. Applying the transfer fraction (TFi) of inhaled activity to the the above equations, the amounts of 137Cs and 144Ce first transfer compartment for a Class D compound that are transferred to the blood as a function of ges may be calculated as follows: tation period are presented in the following table:
Transfer Fraction and Transfer Fraction and Blood Uptake of 137Cs Blood Uptake of 144Ce Stage of Gestation at (Class D) (Class Y)
Time of Intake Transfer Blood Transfer Blood (days) Fraction Uptake Fraction Uptake (TFi0) (3Aci) (TFi) (00Ci)
0 - 30 0.63 0.30 0.050 0.0039
31 - 60 0.63 0.48 0.050 0.0070
61 - 90 1 0.63 0.14 0.050 0.0046 I
D-12
6.3.3 Calculating Embryo/Fetus Dose Third-month intake Equivalent from Maternal Intakes
0.23 gCi x 0.63 x 5.94E-02 rem/gCi Only the Simplified Method will be used in this = 0.009 rem
.xample
13 7 for calculating the embryo/fetus doses. For
- Cs, the approach of the gestation-time dependent TOTAL = 0.055 rem method (the method in Revision 1 to NUREG/
CR-5631) would be similar to the calculations pre Class Y Inhalation Intake--144Ce sented in Case 4, Section 4.3.2, of this Appendix D.
For 144Ce, gestation-time dependent dose factors Dose Equivalent = Intake x TF 1 x DFi have not been developed. The dose to the embryo/fe First-month intake tus is calculated by using Equation 2 from the regula tory position specified in Section 2.5 of this guide. 0.078 gCi x 0.050 x 3.79E-01 rem/RCi From Appendix A, the dose factor for 137Cs is = 0.001 rem
5.94E-02 rem/;Ci (in blood) and for 144Ce is
3.79E-01 rem/jCi (in blood). Applying these dose Second-month intake factors along with the monthly transfer fractions (as 0.14 gCi x 0.050 x 3.79E-01 rem/jxCi calculated above) results in the following dose calcu = 0.003 rem lations:
Third-month intake Class D Inhalation Intake- 137Cs
0.093 pCi x 0.050 x 3.79E-01 rem/gCi Dose Equivalent = Intake x TF1 x DFi - 0.002 rem First-month intake TOTAL = 0.006 rem
0.48 gCi x 0.63 x 5.94E-02 rem/pgCi
= 0.018 rem 6.4 Summing Internal and External Doses Second-month intake The doses to the embryo/fetus for the existing maternal burden, the maternal inhalation intakes,
0.76 jCi x 0.63 x 5.94E-02 rem/gCi and the deep-dose equivalent to the declared preg
= 0.028 rem nant woman are summarized in the following table:
Exposure Pathway and Embryo/Fetus Dose Equivalent Stage of Gestation (rem)
137 Cs 1
44Cs Total Pre-Existing Body Burden 0.068 0.045 0.113 Inhalation Intakes 0.018 0.001 0.019
(0 - 30 days)
Inhalation Intakes 0.028 0.003 0.031
(31 - 60 days)
Inhalation Intakes 0.009 0.002 0.011
(61 - 90 days)
Deep-Dose Equivalent 0.285
(0 - 90 days)
Total 0.459 The sum of the deep-dose equivalent to the de ternal exposures). This total of 0.459 rem is within clared pregnant woman and the embryo/fetus dose 0.05 rem of the 0.5 rem limit for the embryo/fetus.
resulting from the inhalation intakes of the declared Therefore, the dose limit for the embryo/fetus for the pregnant woman represents the total dose equivalent remainder of the gestation period is an additional to the embryo/fetus (i.e., 0.285 rem deep-dose dose of 0.05 rem from the date of the declared preg equivalent, plus 0.174 rem dose equivalent from in- nancy (refer to 10 CFR 20.1208(d)).
D-13
REGULATORY ANALYSIS
A separate regulatory analysis was not prepared copy of the "Regulatory Analysis for the Revision of for this regulatory guide. The regulatory analysis pre 10 CFR Part 20" (PNL-6712, November 1988) is pared for 10 CFR Part 20, "Standards for Protection available for inspection and copying for a fee at the Against Radiation" (56 FR 23360), provides the regu NRC Public Document Room, 2120 L Street NW.,
latory basis for this guide and examines the costs and Washington, DC, as an enclosure to Part 20 (56 FR
benefits of the rule as implemented by the guide. A 23360).
RA-1
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