Regulatory Guide 10.8
| ML003740154 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/1992 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| References | |
| RG-10.8, Rev 2, App X | |
| Download: ML003740154 (8) | |
The revision of 10 CFR Part 20, "Standards for Protection Against Radiation"
(§§ 20.1001
20.2401) changes a number of the requirements for medical use programs. The major change in the re vised Part 20 is to incorporate newer national and in ternational concepts on radiation protection, includ ing the application of a risk-based approach to the establishment of radiation protection limits. Included are the adoption of the "effective dose". concept, specification of occupational dose limits as the sum of internal and external dose, and use of annual limits on intake (ALIs) and derived air concentrations (DACs) as a means for regulating the ingestion and inhalation of radionuclides. The adoption of the ef fective dose concept and the application of the occu pational dose limit to the sum of the internal and ex ternal doses change the methodology to be used for evaluating, controlling, and recording radiation doses.
In addition to the changes to the dose methodology, there are other differences between the provisions of
1.0 CFR 20.1-20.601 and the provisions of 10 CFR
20.1001-20.2401.
Except in those cases in which an applicant pro poses an acceptable alternative method for complying with specified portions of the Commission's regula tions, the methods described in this guide will be used June 1992 IDE
in the evaluation of applications for new licenses or license renewals and for evaluating compliance with
10 CFR 20.1001-20.2401.
Regulatory Guide 10.8 was prepared under the provisions of 10 CFR 20.1-20.601 and 10 CFR Part
35. This new appendix discusses the major dif ferences introduced by the revised 10 CFR Part 20
that modify the guidance previously provided by the NRC for the conduct of medical use programs.
Any information collection activities mentioned in this appendix are contained as requirements in 10
CFR Part 20, which provides the regulatory basis for this guide. The information collection requirements in
10 CFR Part 20 have been cleared under OMB Clear ance No. 3150-0014.
The following are the major areas of medical use programs affected by the revised Part 20.
1. RADIATION PROTECTiON PROGRAMS
(See Appendix G to Regulatory Guide 10.8)
In the revised Part 20, 10 CFR 20.1101 requires each licensee to develop, document, and implement a radiation protection program appropriate to the scope and extent of the activities conducted and to review at least annually the program content and its USNRC REGUIATORY GUIDES
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d. Methods and
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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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U.S. NUCLEAR REGULATORY COMMISSION
REGULATORY GU
OFFICE OF NUCLEAR REGULATORY RESEARCH
APPENDIX X
(Draft was issued as DG-0002)
GUIDANCE ON COMPLYING WITH NEW PART 20 REQUIREMENTS
to Regulatory Guide 10.8, Revision 2,
"Guide for the reparation of Applications for Medical Use Programs*
implementation. Further, 10 CFR 20.1101 requires that each licensee use engineering controls and proce dures to ensure that occupational doses and doses to members of the public are as low as is reasonably achievable (ALARA). In addition, 10 CFR 20.2102 provides the recordkeeping requirements for radia tion protection programs.
SThe requirements in 10 CFR 20.1101 are consis tent with the requirements for control of occupational exposures in 10 CFR Parts 33 and 35. Radiation pro tection programs that have been established under the requirements of 10 CFR Parts 33 and 35 will be considered to be acceptable to meet the occupational ALARA requirements of the revised 10 CFR Part 20
when the program activities are limited to external oc cupational exposures. However, licensees who handle unsealed radioactive materials that may cause internal exposure to members of the public will need to sup plement their ALARA programs to address potential internal as well as external doses to members of the general public from effluents to unrestricted areas.
Additional guidance is being developed on this, and it will be addressed in a separate regulatory guide. Li censees should establish ALARA goals or objectives for effluents.
In developing an ALARA radiation protection program, licensees should design the program based on the size of the licensed facility, the potential haz ards associated with radiation exposure, the potential intake of radioactive material, and the physical char acteristics of the radionuclides (i.e., solid, liquid, or gas). For example, the magnitude of an ALARA pro gram for a large research hospital would be expected to be considerably more comprehensive in scope than a radiation protection program for a private practice physician. The program should include the mecha nisms for periodic (at least annually) review of per formance, as well as actions to be taken when ALARA goals or objectives are not met.
The revised 10 CFR Part 20 does not require that a numerical cost-benefit analysis (quantitative ap proach) be used to demonstrate ALARA. However, NRC encourages medical licensees to use quantitative analyses in developing ALARA programs and proce dures. If it can be performed readily, licensees should demonstrate through quantitative analysis that the cost and benefits associated with design, engineering controls, and operating procedures have been opti mized in accordance with the ALARA principle. If a quantitative analysis cannot be readily performed, li censees should thoroughly evaluate any design or en gineering controls that may need to be changed to keep operating procedures ALARA.
Examples of the type of ALARA optimization considerations appropriate to the conduct of medical use programs are presented in the National Council on Radiation Protection and Measurement (NCRP)
Report No. 107, "Implementation of the Principle of
.As Low As Is Reasonably Achievable (ALARA) for Medical and Dental Personnel,"'
December 31,
1990. This NCRP report provides specific hypotheti cal examples of optimization decisions in implement ing ALARA in nuclear medicine and radiation oncol ogy.
2.
INTERNAL DOSE
METHODOLOGY
The revised 10 CFR Pan 20 incorporates the new dose methodology system developed by the Interna tional Commission on Radiological Protection (ICRP), which specifies radiation dose limits in terms of an "equivalent" whole body dose, taken to be the sum of individual organ committed doses weighted by the risk of biological effect for each of the organs irra diated. This effective dose equivalent concept is used to control the stochastic biological effects of exposure to ionizing radiation. Nonstochastic, or threshold, biological effects are avoided by establishing dose lim its for the committed dose received by an individual organ and for the exposure to the skin and to the lens of the eye (see 10 CFR 20.1201).
2.1 Units and Terms for Internal Exposure The revised 10 CFR Part 20 uses the "special"
units of dose and activity and presents the corre sponding values for the international system (SI). Re cords and reports required under the revised Part 20
are to be maintained using the "special" units.
The following table provides the conversions be tween the two systems of measurement:
Special Units (Activity) curie (Ci)
(Absorbed dose) rad (Dose equivalent) rem SI Units (Activity) becquerel (Bq)
(Absorbed dose) gray (Gy)
(Dose equivalent)
sievert (Sv)
= 3.7 x 1010 disintegra tions per second
(3.7 x 1010 Bq)
= 100 ergs/gram
(0.01 Gy)
= Quality factor x rad
(0.01 Sv)
= 1 disintegration per second
(2.7 x 10-11 Ci)
= 1 joule/kg (100 rads)
= Quality factor x grays
(100 rerns)
In addition, the revised Part 20 introduces new terms for radionuclide intakes by means of inhalation
"and ingestion, e.g., derived air concentration (DAC).
- NCRP reports can be purchased by writing to NCRP Publi cations, 7910 Woodmont Avenue, Suite 800, Bethesda, MD 20814.
10.8-2
For a few radionuclides (e.g., noble gases such as xe non), the terms apply to exposures from submersion.
The new term DAC is used, in broad terms, similar to the way in which the maximum permissible concentration (MPC) is used in Appendix B, Table I,
Column 1, to 10 CFR 20.1-20.601 and 20.103. Ex posure to airborne radioactivity at a level of I DAC
for 1 year (2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />) would result in either a com mitted effective dose equivalent of 5 reins (50 mSv)
or a committed dose equivalent of 50 rems (0.5 Sv)
to any individual organ or tissue, with no considera tion for the contribution of external dose. In order to show compliance with the occupational dose limit of 5 rems (50 roSv), a facility must consider the contribu tions of internal and external doses prior to calculat ing ventilation and gas clearance time.
Appendix 0 to this Regulatory Guide 10.8 pro vides model procedures for calculating worker doses from concentrations of gases in work areas and for calculating spilled gas clearance times. The procedure states that the MPC values for the radionuclide of in terest should be used in the calculations. To imple ment the revised Part 20, the DAC value for the radionuclide of interest, in conjunction with the con tribution of external dose, must be used instead of the MPC value. For example, consider the following sim plified approach to determining required ventilation rates in an area where xenon-133 procedures will be performed:
Example A new room is being designed in an existing nuclear medicine department where xenon-133 ventilation studies will be performed. You are asked to calculate the minimum ventilation rates required to maintain compliance with the occupational dose limits.
I. Determine the highest dose to an individual from all external radiation for the previous 12-month period by reviewing personnel monitoring records (film, TLD, etc.). If necessary, modify the dose to account for an anticipated increase or decrease in patient workload.
2.
MQdify the DAC value for xenon-133 to allow for the estimated annual external exposure.
A simplified method is to subtract the estimated external dose from the occupational dose limit of
5 reins (50 mSv) and divide this number by 5 reins. This yields the fraction of the dose limit of
5 reins that would still be permitted from internal sources. Multiplying this fraction times the DAC
value yields a modified DAC. These DAC values are provided in Appendix B to
10 CFR
§§ 20.1001-20.2401 in Table 1, Column 3.
The annual external dose is 2 rems. The listed DAC value for xenon-133 is 1E-4 gCi/ml. The modified DAC value should be based on 3 reins that could still be incurred from internal expo- sure.
"d
5 remsx 1-4 i/il
= 6E-5gCi/ml
3.
Calculate the minimum ventilation rates for the room using the procedure provided in Appendix
0 to this Regulatory Guide 10.8. In place of the MPC value stipulated in Appendix 0, use the modified DAC value. In the example provided above, the modified DAC value (6E-5 gCi/ml)
would be used instead of the MPC value for xe non-133.
The discussion and example presented in this section do not specifically address ALARA and the monitoring thresholds for internal doses as it relates to the summation of internal and external dose. How ever, it should be noted that modifications to ventila tion rates can be a means to maintaining exposures ALARA. In addition, increased ventilation rates may negate the requirement to monitor internal dose and, as such, may eliminate the necessity to sum internal and external dose to show compliance with the occu pational dose limits.
2.2 Occupational Dose Limits In 10 CFR 20.101, the quarterly occupational dose limit of 1.25 reins (5 rems in a year)
applies only to whole body exposures to external radiation
(10 CFR 20.101). If the licensee has a dose history and a worker's cumulative dose is less than 5(age-18)
reins, the worker could be allowed under certain cir cumstances to receive occupational exposure in ex cess of the 10 CFR 20.101(a) limit up to 3 rems per quarter (10 CFR 20.102(b)). In addition to the
5-remi annual total for occupational external expo sure, 10 CFR 20.103 specifies a separate limit to ap ply to exposures to concentrations of radioactive ma terials in air in restricted areas (10 CFR 20.103 and Column 1, Table 1, of Appendix B to §§ 20.1
20.601).
The revised Part 20 applies the 5-rem (50-mSv)
occupational dose limit as a whole body "effective".
dose. This limit is the sum of the deep-dose equiva lent from external sources and the committed effec tive dose equivalent to the organs exposed -from the internal uptake of radionuclides, expressed as the to tal effective dose equivalent (10 CFR 20.1201). Ad ditional guidance is provided in Regulatory Guide
8.34, "Monitoring Criteria and Methods To Calculate Occupational Doses," on the methods to be used for determining these dose equivalents. Revision 1 of Regulatory Guide 8.7, "Instructions for Recording and Reporting Occupational Radiation Exposure Data," provides guidance on reporting the dose data on NRC Forms 4 and 5. The revised Part 20 no longer contains provisions for an age proration
5(N-18).
10.8-3
- 2.3 Effective Dose Equivalent The effective dose equivalent concept described above makes it possible to combine both the internal and external doses in assessing the overall risk of health effects to an individual. Prior to the revision of Part 20, the activity concentration limits for intakes of a single radionuclide (in Appendix B to §§ 20.1
20.601) were based on controlling the dose to the organ receiving the highest dose ("critical organ").
These concentration limits, however, were treated separately from the dose limits for external exposure.
The revised 10 CFR Part 20 dose methodology evalu ates the doses to all major body organs, multiplies these doses by the appropriate organ weighting fac tors, and then sums the organ-weighted doses to ob tain a whole body risk-weighted "effective dose." The ALIs and DACs in Appendix B to §§ 20.1001
20.2401, therefore, reflect the doses to all principal organs that are irradiated, not just the one organ that receives the highest dose, as was done previously.
3.
DECLARED PREGNANT WOMEN
[Embryo/Fetus Dose Limits]
(See 10 CFR 20.1003 and 20.1208)
The revised Part 20 uses the term "declared pregnant woman" to mean a woman who has volun tarily informed her employer, in writing, of her preg nancy and the estimated date of conception.
For declared pregnant women, the NRC limits the dose to the embryo/fetus to 0.5 rem (5 mSv) over the entire pregnancy. In addition, the licensee is re quired to make an effort to avoid substantial variation above a uniform monthly exposure rate (0.05 rem/
month) (0.5 mSv/month). Declared pregnant women are not allowed to receive planned special exposures that involve whole body doses or maternal intakes that could result in exceeding the embryo/fetus dose limit. The radiation protection program should make provisions for instructing women workers about the special need to protect the embryo/fetus and to en courage them to promptly notify their employer if they become pregnant. Regulatory Guide 8.36, "Ra diation Dose to the Embryo/Fetus," contains guid ance on evaluating the dose to the embryo/fetus.
4.
LEVELS IN UNRESTRICTED AREAS
(See 10 CFR 20.1301 and 20.1302)
The revised Part 20 uses the following terms with regard to areas with or without radiological restric tions:
"Controlled area" means an area, outside of a restricted area but inside the site boundary, access to which can be limited by the licensee for any reason.
"Entrance or access point" means any location through which an individual could gain access to ra diation areas or to radioactive materials. This includes entry or exit portals of sufficient size to permit human entry, irrespective of their intended use.
"Radiation area" means an area, accessible to in dividuals, in which radiation levels could result in an individual receiving a dose equivalent in excess of 5 mrem (0.05 mSv) in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at 30 centimeters from the radiation source or from any surface that the ra diation penetrates.
"Restricted area" means an area, access to which is limited by the licensee for the purpose of protecting individuals against undue risks from exposure to ra diation and radioactive materials. Restricted area does not include areas used as residential quarters, but separate rooms in a residential building may be set apart as a restricted area.
"Site boundary" means that line beyond which the land or property is not owned, leased, or other wise controlled by the licensee.
"Unrestricted area" means an area, access to which is neither limited nor controlled by the licen see.
The radiation levels in unrestricted areas from operations or releases of radionuclides in effluents are restricted to 2 mrem (20 i+/-Sv) in any 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from external sources and to 100 mrem (1 mSv) in a year total effective dose equivalent for individual members of the public. Depending on how the licensee's hospi tal areas are controlled and monitored, hallway areas outside patient therapy rooms and diagnostic areas will usually need to be limited to the radiation levels for unrestricted areas.
5.
NVLAP PROCESSORS
(See 10 CFR 20.1501)
Personnel dosimeters that require processing to determine the dose to compare to the 10 CFR Part 20
dose limits must be processed and evaluated by a dosimetry processor that is accredited under the Na tional Voluntary Laboratory Accreditation Program (NVLAP).
6. CONTROL OF LABORATORIES
(See 10 CFR 20.1101, 20.1702, 20.1801,
20.1802, and 20.1902)
Access to laboratories using radionuclides, as well as the work practices in these laboratories, need to be controlled. Controlling access to radionuclide labora-.
tories is accomplished by posting the entrance door and locking all accessible entrances to the laboratory when an authorized user, or an individual under the supervision of an authorized user, is not present. An acceptable alternative is to provide lockable storage facilities within the laboratory.
In
10
CFR
20.1902(e), posting is required for each area or room in which there is used or stored a quantity of licensed material exceeding 10 times the quantity in Appendix
10.8-4
C to §§ 20.1001-20.2401. Some of the Appendix C
quantities are changed. Appendix I to Revision 2 of Regulatory Guide 10.8 provides model rules for safe use of radiopharmaceuticals that can be used for radionuclide laboratories, and Appendix J provides model spill procedures.
7.
POSTING AND CONTROLLING ACCESS
TO PATIENT ROOMS
(See 10 CFR 20.1903(b))
When patients have received therapeutic admini strations of radionuclides or therapeutic applications of sealed sources, the criteria for exceptions to post ing requirements specified in 10 CFR 20.1903 will likely be exceeded. Dose rates from therapy patients can often exceed 5 mrem (50 ASv) per hour at 1 me ter from the patient. Under these conditions, the en trance to the patient's room must be posted and ac cess to the area controlled. Access can be controlled by routine surveillance and by posting instructions for hospital personnel and visitors at the entrance to the patient's room. Examples of such instructions can be found in Exhibit 17 of this Regulatory Guide 10.8.
Systems such as remote TV surveillance, electronic eye, or personnel entry detection devices are consid ered acceptable for monitoring personnel access to the patient's room.
Note that 10 CFR 20.1903 allows exceptions to the posting requirements if specific conditions are met. Licensees should review 10 CFR 20.1902 and
1903 for posting requirements since some of the post ing language has changed.
8.
EXEMPTIONS TO LABELING
REQUIREMENTS
(See 10 CFR 20.1905)
Licensees are not required to label containers.
holding licensed material in quantities less than the quantities listed in Appendix C to §§ 20.1001
20.2401. For iodine-125, carbon-14, and sulfur-35, the quantities below which labeling is not required are
1 gCi, 1000 .Ci, and 100 .Ci, respectively. In addi tion, licensees are not required to label containers holding licensed material in concentrations less than those specified in Table
3 of Appendix B to
20.1001-20.2401. For iodine-125, carbon-14, and sulfur-35, the exemption concentrations are 2 x 10-s MiCi/ml, 3 x 10-4 gCi/ml, and 1 x 10-3 giCi/ml, respec tively.
9. PROCEDURES FOR RECEIVING AND
OPENING PACKAGES
(See 10 CFR 20.1906(c) and 20.1906(d))
In the revised Part 20, 10 CFR 20.1906 modifies the Type A package quantity limits affecting package opening procedures, monitoring required for radioac- tive contamination on external surfaces of a package, and surface contamination levels requiring notifica tion of the NRC as follows:
Special requirements must be followed for packages containing quantities of radioactive material in excess of the Type A quan tity limits specified in 10 CFR 71.4 and Appendix A
to Part 71 (e.g., more than 20 curies of molybde num-99; 100 curies of technetium-99m; 10 curies of iodine-131, cesium- 137, or iridium-192; or more than
70 curies of iodine-125). All shipping packages re ceived, known to contain radioactive material, must be monitored for radioactive contamination and ra diation levels if the package is labeled according to U.S. Department of Transportation rules (i.e., la beled with White I, Yellow II, or Yellow III) as con taining radioactive material or if there is evidence of damage to the package. Such packages must be moni tored for external radiation levels and surface con tamination within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after receipt if received during working hours, or within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> from the be ginning of the next working day if received after working hours, in accordance with the requirements of 10 CFR 20.1906. The NRC Regional Office and the final delivery carrier must be notified immediately if removable contamination exceeds the limits of 10
CFR 71.87(i) or the external radiation levels exceed the limits of 10 CFR 71.47. Note that these Appendix X procedures for receiving and opening packages do not exempt packages containing less than Type A
quantities of radioactive material from removable contamination surveys as does 10 CFR 20.205(b) and Appendix L to this Regulatory Guide 10.8. There fore, it may be necessary for a licensee to revise cur rent package opening procedures to reflect the changes in the revised Part 20.
10. EFFLUENT RELEASES TO SEWER
In the revised Part 20, 10 CFR 20.2003 allows licensees, under certain quantity release constraints, to discharge licensed material into sanitary sewers if the material is readily soluble in water or if the mate rial is readily dispersible biological material. Dispers ible in this context means able to be distributed as particles, more or less evenly throughout a medium, such as a sewer system. In practical terms, biological material should be divided finely enough so as to mix readily with a water stream and continue -to disperse rather than to reconcentrate. This provision of the revised Part 20 allows continuation of the practice of discharging readily dispersible biological materials such as ground-up animal carcasses. The prohibition of the discharge to sanitary sewer systems of nonbiological insoluble materials by § 20.2003 was designed to minimize the accumulation of insoluble material in the sewer system, treatment plant, and in sewage sludge.
Licensees should note that the monthly average concentrations of radionuclides allowed to be released to sanitary sewers under
10.8-5
10 CFR 20.2003 and Table 3 of Appendix B to
§§ 20.1001-20.2401 are, generally, 10 times more restrictive than the monthly average concentrations that have been allowed to be released into sanitary sewer systems under 10 CFR 20.303(c). In addition, the licensee should note that there are no longer daily concentration limits for release of material to the sanitary sewer as discussed in Appendix R to this Regulatory Guide 10.8.
10.8-6
REGULATORY ANALYSIS
A separate regulatory analysis was not prepared for this Appendix X to Regulatory Guide 10.8. The regulatory analysis prepared for 10 CFR Part 20,
"Standards for Protection Against Radiation" (56 FR
23360). provides the regulatory basis for this appen dix and examines the costs and benefits of the rule as implemented by the guide. A copy of the "Regulatory Analysis for the Revision of 10 CFR Part 20"
(PNL-6712, November 1988) is available for inspec tion and copying for a fee at the NRC Public Docu ment Room, 2120 L Street NW, Washington, DC, as an enclosure to Part 20.
10.8-7
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