Regulatory Guide 8.23

Radiation Safety Surveys at Medical Institutions

ML13064A091
Person / Time
Issue date:	02/28/1979
From:	NRC/OSD
To:
References
RG-8.023
Download: ML13064A091 (14)

U.S. NUCLEAR REGULATORY

COMMISSION

February 1979 REG ULATO RY G U [ D 0j"E OFFICE OF STANDARDS

DEVELOPMENT

REGULATORY

GUIDE 8.23 RADIATION

SAFETY SURVEYS AT MEDICAL INSTITUTIONS

A. INTRODUCTION

Paragraph

20.201(b)

of 10 CFR Part 20, "Stand-ards for Protection Against Radiation," requires that each licensee make or cause to be made such surveys as may be necessary for him to comply with the regu-lations in Part 20. As used in Part 20, the term "sur-Surveys t are a necessary supplement to personnel monitoring, which measures individual radiation ex-posures by the use of devices worn b, the workers (Refs. 3, 5, 6, 8, and 9).C. REGULATORYAPOSITI

N, vey" means an evaluation of the radiation hazards Methods and procedureI

uuide are accept-incident to the production, use, release, disposal, or able to the NRC staff4r estab,1jshJmg acceptable sur-presence of radioactive materials or other sources of vey programs in aceordane wrlT the as low as is rea-radiation under a specific set of conditions.

This sonably achievnbep ( RApq'hilosophy.

Generally, guide identifies the types and frequencies of surveys medical instituti n's icenseod by the NRC should have that are acceptable to the NRC staff for use in medi- a health,(s cs a Aivailable for consultation to de-cal institutions licensed by the NRC to use radioac- sign -surv'IT\-

p am appropriate to the institution's tive materials for purposes of diagnosis, therapy, or usei dioa&1 tie material.research.Tgý pesaf Surveys

B. DISCUSSION

1tý Gineral Description Surveys are considered to be part of a comrr reen- Surveys performed in compliance with §20.201 of sive protection program established by iceln l 10 CFR Part 20 should include those necessary to consistent with the philosophy and princil),les of eg- evaluate external exposure to personnel, surface con-ulatory Guide 8.10, "Operating Philosoph

4or 1 in- tamination levels, and concentrations of airborne taining Occupational Radiation Exposures A ,w As radioactive materials in the facility and in effluents Is Reasonably Achievable. " rinciples, methods, and from the facility.instrumentation for carryiie.g iut radiation and con- Environmental monitoring is beyond the scope of tamination surveys we!d(e: ped early in the this guide. However, the radiation safety program atomic energy progriar.

andtlhave been discussed in should include surveys or records that indicate con-reports of the Nafjonai loounc on Radiation Protec- trol of the quantities of radioactive material released tion and Meabure 'ent,_,1(1-RP) (Refs. 1-3), the In- in air and water to unrestricted areas, as required by ternational

' y Agency (IAEA) (Refs.4-8), and thf Iýiternational Commission on Radiolog- The word "survey,'

often used synonymously with "'surveil- ical Protection

&!CRP) (Ref. 9). More recent reports lance," "monitoring,

or "area monitoring," is used in this (uide to connote the personal inspection of various locations in (Refs. 10-14) contain additional information for use a facility using radioactive materials, with or without accom-in establishing radiation survey programs and select- panying measurements, to determine the effectiveness of meas-ing methods and equipment for their implementation.

ures to protect against exposure to radiation.

USNRC REGULATORY

GUIDES Regulatory Guides are issued to describe and make available to the public methods acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate techniques used by the staff in evalu-ating specific problems or postulated accidents, or to provide guidance to applicants.

Regulatory Guides are not substitutes for regulations, and com-pliance with them is not required.

Methods and solutions different from those set out in the guides will be acceptable if they provide a basis for the findings requisite to the issuance or *continuance of a permit or license by the Commission.

Comments and suggestions for improvements in these guides are encouraged at all times, and guides will be revised, as appropriate, to accommodate com-ments and to reflect new information or experience.

However, comments on this guide, if received within about two months after its issuance, will be particularly useful in evaluating the need for an early revision.Comments should be sent to the Secretary of the Commission, U.S. Nuclear Regulatory Commission, Washington, D.C. 20555, Attention:

Docketing and Service Branch.The guides are issued in the following ten broad divisions:

1. Power Reactors 6. Products 2, Research and Test Reactors

7. Transportation

3. Fuels and Materials Facilities

8. Occupational Health 4. Environmental and Siting 9. Antitrust and Financial Review 5. Materials and Plant Protection

10. General Requests for single copies of issued guides (which may be reproduced)

or for placement on an automatic distribution list for single copies of future guides in specific divisions should be made in writing to the U.S. Nuclear Regulatory Commission, Washington, D.C. 20555, Attention:

Director, Division of Technical Information and Document Control.

Part 20. In many medical institutions, surveys of effluents or calculations to ensure that permissible concentration limits are not exceeded are included as a regular part of the health physics survey program.Often these calculations may be made by estimating the amounts of radioactive material washed down des-ignated sinks and dividing them by the quantities of sewage released from the hospital, as indicated on the hospital's water or sewage bills. This procedure nor-mally suffices to show compliance with the effluent limits of Part 20. Amounts of radioactive material re-leased in air within hospitals, or exhausted to the out-side from hospitals, are generally small but may sometimes be estimated by calculational techniques if not by air-monitoring procedures.

Appendix A to this guide describes surveys to be made of radioactive xenon-133 releases.Radiation protection programs should include the types of surveys discussed below.1.2 Surveys of External Radiation Exposure Levels Areas to be surveyed should include any locations where individuals may.be exposed to radiation inten-sities that might cause the occupational radiation dose to exceed 10 percent of the limits of paragraph 20.101(a)

in any calendar quarter or where an indi-vidual is working with any radiation source that could produce radiation levels greater than 1.0 mR/h at 1 meter. These areas typically include shipping and re-ceiving areas; isotope laboratories in nuclear medicine;

diagnostic areas in nuclear medicine;

in-tracavitary source preparation areas in radiation ther-apy; patients'

rooms where treatments are given with intracavitary, interstitial, or radiopharmaceutical therapy sources; operating rooms: control (console)areas for teletherapy equipment rooms; waste pack-aging and disposal areas; radiation instrument cali-bration areas; and any other areas where persons might be exposed (e.g., areas occupied by technologists, nursing staff, visitors, patients, or any other persons who may be exposed to radioactive materials handled by others).Preoperational, routine, and special surveys of these areas should be performed by the radiation pro-tection staff as described in Section C.2 of this guide.Results of these surveys should be recorded as de-scribed in Section C.3. In addition to this survey pro-gram, the Radiation Safety Officer should institute and maintain a program of surveys performed by workers other than health physics personnel who may be exposed to external radiation levels that could ex-ceed any of the limits of paragraph

2 0.101(a).

Sur-veys by such workers may consist of no more than occasional instrument observations during work with radioactive materials.

These personal surveys are par-ticularly appropriate in nuclear medicine activities.

Personnel should be properly instructed in conducting such surveys and should perform the surveys each day during and after work with radioactive materials, as necessary to determine the need to limit worktime and to use protective procedures to reduce exposures as far below the paragraph

20. 101(a) limits as is rea-sonably achievable.

The survey results obtained by these workers need not be recorded.

However, the Radiation Safety Office should maintain records to show that the appropriate training for, and implemen-tation of, the worker survey program has been pro-vided and is a continuing part of the survey program.Workers should be instructed to report unusual sur-vey findings to the Radiation Safety Officer.Surveys are not acceptable for routine compliance with the personnel monitoring requirements of§20.202. However, in the event of accidental loss of personnel dosimetry data, e.g., as a result of losing the dosimeter or chemical or physical damage to the dosimeter, the best alternative means of estimating the exposure may be to use survey data in conjunc-tion with appropriate occupancy factors. In such case, the estimate, including the survey data used, should be documented and retained indefinitely (see paragraph

20.401(c)(2)(ii)).

Survey results should be reviewed carefully by the Radiation Safety Officer to identify potentially hazardous situations and un-favorable trends.1.3 Measurements of Radioactive Material Con-centrations in Air It may often be sufficient in medical institutions to show by calculation, together with monitoring of ven-tilation rates, that air concentrations are well below levels that would require routine air sampling.

How-ever, concentrations of radioactive material in air should be measured, at frequencies specified in Sec-tion C.2. for areas where operations could expose workers to 10 percent or more of the concentration values given in Table 1, Column 1, of Appendix B to 10 CFR Part 20. Special requirements for such monitoring may also be made a condition of the license.Air samples obtained in accordance with §20.103 should be representative of the air in the workers'breathing zone. In cases where breathing zone sam-pling is not accomplished, air samples taken outside the breathing zone closer to the source, where the concentration of radioactive material can or is ex-pected to be equal to or greater than the concentration in the breathing zone, are acceptable.

When measur-ing the quantity of radioactive material deposited on an air sample filter, corrections should-be made for 8. 2 3- 2 absorption of alpha or beta particles by the filter media and by material collected on the filter. The quantity of air that has passed through the filter should be accurately measured and corrections made for any loss of flow rate due to the accumulation of material on the filter.Continuous breathing zone or general air sampling should be conducted while the work is in progress unless experience with sample results or calculations has demonstrated that the concentration of radioac-tive material in the breathing zone is not likely to exceed 25 percent of the values given in Table 1, Column 1, of Appendix B to 10 CFR Part 20. The use of personal (lapel) samplers is acceptable for breathing zone sampling.

If the air sampling is not continuous, the frequency and the times selected for the sampling should be based on the nature of the process involved and the probability that airborne radioactive material will be present. When assessing this probability is difficult, frequencies based on in-formation given in Section C.2 and Table I of this guide are acceptable.

1.4 Surface Contamination Surveys Regular surveys for radioactive contamination that could be present on surfaces of floors, walls, furnish-ings, and equipment are a necessary part of the sur-vey program. Any surveys carried out in accordance with NRC license conditions will be considered con-sistent with the level of safety provided by recom-mendations in this guide.Control of surface contamination is necessary to limit external dose rates and the resuspension of loose radioactive materials that may enter the body through inhalation, ingestion, or skin absorption.

1.4.1 Removable Contamination For the purposes of this guide, removable con-tamination means radioactivity that can be transferred from a surface to a smear test paper by rubbing with moderate pressure.

Information is available on the selection and use of instruments for performing re-movable surface contamination surveys appropriate to the radionuclides used in medical institutions (Refs.1-14). Methods and instruments used in surface contamination surveys should be sufficiently sensi-tive to detect the nuclides being monitored (Refs.11-14). For optimum detection of low-energy beta emitters (e.g., H-3 and C-14) as well as of alpha emitters and low-energy x- or gamma-ray emitters (e~g., 1-125), liquid scintillation counting or internal proportional counting is normally necessary with the use of appropriate constancy checks on counter effi-ciency.The collection of smear samples may be pre-ceded by a rapid survey with a portable, thin-end-window detector in order (a) to ensure that gross contamination levels are not already too high for counting with sensitive equipment, (b) to minimize (in some cases) the chance for inadvertent, spread of contamination by the contamination survey or other activities to be performed in the meantime, and (c) to determine which areas require greater attention in smear testing. The instrument used for this purpose should have a short time constant on the order of 1 second or less to facilitate detection.

A standardized method for smear testing of a relatively uniform area should be used in order to allow comparison of relative levels of contamination at different times and places. A dry smear taken from an area of about 100 cm 2 is acceptable to indicate levels of removable contamination.

A layout diagram for each laboratory routinely surveyed is helpful for recording survey results in a uniform manner to aid review and observation of trends and for satisfying regulatory requirements for availability of survey records. On these diagrams, it is helpful to specify key locations that are smear tested at each survey and also to provide space re-minding the recorder to include: a. Contamination levels converted to radioactiv- ity units specified in 10 CFR Part 20, b. Make and model number of the instruments used in the survey and in counting the smear samples, c. Disintegration rate of each instrument test or calibration source, d. Sample, backgrbund, and test counts and times, and e. Signatures at the bottom of each page.Provision should also be made on the diagram for recording an instrument check with an appropriate check or calibration source for each batch of smear samples counted.The surveys discussed above are regularly scheduled and recorded on the survey diagrams.

In addition, it may be necessary to conduct more fre-quent, informal, and unrecorded surveys in nuclear medicine areas or other areas where loose radioactive contamination may occur. Such surveys can be made with a thin-end-window (less than 2 mg/cm 2) detector held close to a smear sample immediately after it is taken in the working area. When ambient external radiation levels in the laboratory are low enough to maintain external radiation exposures below the lim-8.23-3 its of paragraph

20.101(a), any appreciable surface contamination can be detected by simply holding the detector in a fixed position and moving the smear sample close to and away from the detector several times. This method may be used for the vast majority of radionuclides used in diagnostic and therapeutic medical practice.Part 20 does not specify limits for surface con-tamination.

Each applicant may propose and justify what removable surface contamination limits will be allowable before decontamination will be performed.

These limits should be based on the need to avoid transfer of si2nificant amounts of contamination to unrestricted areas and to maintain exposures as low as is reasonably achievable.

The contamination limits for restricted areas presented on line 2 of Table 2 of this guide are acceptable to the NRC staff and need not be justified by the licensee or applicant.

1.4.2 Fixed Contamination For the purposes of this guide, fixed contamina- tion means radioactivity remaining on a surface after repeated decontamination attempts fail to signifi-cantly reduce the contamination level. A total con-tamination survey, using instruments suitable for the radionuclides involved, should be conducted simul-taneously with each removable contamination survey.The applicant may propose and justify what total con-tamination limits will be allowable for both restricted and unrestricted areas before decontamination will be performed.

The limits appearing on line 2 of Table 2, multiplied by a factor of 5, are acceptable to the NRC staff and need not be justified by the licensee or applicant.

1.5 Protective and Personal Clothing Contamina- tion Surveys Individuals working in areas where a potential for skin or clothing contamination exists should be pro-vided with suitable protective clothing.

Laboratory coats and protective gloves, as described in Refer-ences 11 and 12, are usually adequate for any proce-dures in medical institutions.

Protective clothing should be surveyed by the wearer after use if signifi-cant contamination is possible.

Contaminated protec-tive clothing should be removed and placed in special laundry containers before leaving a restricted work area. Disposable gloves should be discarded in radioactive waste containers.

After gloves are re-moved, hands should be washed and surveyed.When protective clothing contamination levels may be expected to exceed preselected limits, workers should be instructed to take care to avoid dispersal of contamination and to report the situation to the Radia-tion Safety Office. A member of the radiation safety staff should then survey and supervise any necessary decontamination or clothing disposal.

The applicant may propose and justify protective clothing contami-nation limits considered adequate for use in each re-stricted area. The limits on line 4 of Table 2 are ac-ceptable to the NRC staff and need not be justified by the licensee or applicant.

Contamination levels observed and procedures fol-lowed during survey and decontamination of personal clothing should be recorded.

The written record should include the names of persons surveyed, a de-scription of prior work activities, the probable causes, steps taken to reduce future incidence of con-tamination, times and dates, and the surveyor's signa-ture. This information may be entered in a logbook.Individual worker surveys of themselves need not be routinely recorded unless the limits on line 4 of Table 2 are exceeded.

The radiation safety staff should conduct spot-checks monthly to ensure that the work-ers continue their own personal contamination sur-veys.In restricted areas with little potential for surface contamination, personal clothing is often worn be-neath protective clothing.

Such personal clothing should be surveyed by the wearer before he or she leaves the restricted area. (However, this is neither practicable nor necessary for employees working with only microcurie quantities of tritium or carbon-14.)

Workers should be instructed to report the situation to the Radiation Safety Office when personal clothing contamination levels exceed preselected limits. A member of the radiation safety staff should then sur-vey and supervise any necessary decontamination or clothing disposal.

The applicant or licensee may pro-pose and justify personal clothing contamination lim-its; the limits given on line 3 of Table 2 are accept-able to the NRC staff and need not be justified by the applicant or licensee.

Records should be maintained in the same manner as those for protective clothing contamination.

1.6 Personal Surveys Although personal contamination in excess of the value given on line 5 of Table 2 is unusual in medical institutions, individuals who work in restricted areas under conditions in which they may become contami-nated should survey all exposed areas of the body be-fore donning personal clothing or leaving the re-stricted area. Particular attention should be paid to the body, hair, bottoms of the shoes or feet, and the hands. Workers should be instructed to report the de-tection of contamination on the body to the Radiation Safety Office. Decontamination attempts, under the direction of Radiation Safety Office personnel or a 8.23-4 medical consultant, should be repeated until (a) such attempts cease to effect significant reductions or (b)such attempts threaten to irritate or harm the skin .2 When decontamination attempts are terminated, there should .be no further concern if the residual contami-nation does not exceed preselected levels. Such levels may be proposed and justified by the applicant or licensee.

The limits given on line 5 of Table 2 will be accepted without justification.

If residual contamina- tion exceeds the selected limits, the affected indi-vidual may be released (since his contamination is now relatively fixed and not likely to enter the body), but periodic surveys should be made until the limits are no longer exceeded.

The resulting dose should be determined and entered in the individual's personnel dosimetry record. Complete records should be main-tained of each incident of this nature.Since medical personnel may often handle open vials or containers with millicurie or higher levels of volatile forms of certain nuclides such as 1-125, 1-131, and Tc-99m, which in certain forms may con-centrate in the thyroid or other body organs, bioassay monitoring is sometimes made a condition of the license. Acceptable criteria for such programs are published in other guides and are available from the License Management Branch. In addition to these programs, placing the detector against the neck close to the thyroid is often useful for monitoring for inter-nal deposition of these nuclides during surveys for skin contamination;

however, for 1-125 a thin crystal scintillation probe would be needed to obtain adequate sensitivity.

In this way, appropriate person-nel may be more frequently monitored for internal exposure while they are also being monitored for ex-ternal contamination.

Any positive indications from these types of surveys should be recorded in the radi-ation safety logs. Indications of internal depositions should be reported to the Radiation Safety Office.1.7 Surveys of Equipment Prior to Release to Un-restricted Areas Before the uncontrolled release of potentially con-taminated medical instruments or equipment from re-stricted to unrestricted areas, surface contamination surveys should be conducted on such instruments and equijment for both removable and fixed contamina- tion. If contamination is detected, decontamination

2 Decontamination attempts without supervision or instruction from the licensee's medical consultant should be restricted to washing with mild soap and water unless other safe procedures have already been approved and personnel have been properly instructed in applying them. If such attempts do not reduce the contamination to acceptable levels, the aid of the licensee's medical consultant should be obtained.procedures should be instituted and repeated until ad-ditional efforts do not significantly reduce contami-nation levels. The applicant or licensee may propose and justify total and removable contamination limits below which uncontrolled release of equipment is permitted.

The limits given in Table I of Regulatory Guide 1.86. "Termination of Operating Licenses for Nuclear Reactors,'" are acceptable to the NRC staff and need not be justified by the licensee or applicant.

1.8 Ingestion Surveillance should be included in the radiation safety program to ensure that workers properly ob-serve rules to prevent ingestion of radionuclides, e.g., rules against eating, drinking, or smoking in work areas or while wearing potentially contaminated clothing;

storing foods in work areas; pipetting by mouth; and wearing contaminated laboratory coats to the cafeteria or other unrestricted areas. Water foun-tains close to radioactivity work areas should be smear tested regularly.

1.9 Surveys of Packages Received and Packages Prepared for Shipment External radiation measurements and tests of ex-ternal surfaces of packages received or packaged for shipment should be carried out near the receiving or packaging point to avoid unwarranted radiation expo-sures and inadvertent contamination of personnel or the hospital.

Surveys and labeling must comply with the NRC's regulations (see §§20.203, 20.205, 32.19, and 32.70 through 32.74 of 10 CFR) and with any specific license conditions.

Delivery of packages within the hospital should also be monitored.

Any de-livered containers of radioactive material must be labeled, as required by paragraph

20.203(f).

All packages bearing yellow I or yellow III labels should be transported by cart. Only adequately shielded sources should be transported.

Internal containers of packages containing significant amounts of radioac-tive materials should not be opened until the contain-ers have been placed in the appropriate protective facility (e.g., hood).All personnel, including security guards, should be adequately instructed in performing at least an initial inspection survey for leakage, or damage, before transporting any packages of radioactive materials through hospital areas. The instructions should clearly indicate which packages should be transported by cart rather than hand-carried.

1.10 Checks on Posting of Caution Signs, Labels, Signals, Controls, and Notices to Employees The radiation safety staff should perform surveil-lance at least weekly to ensure that signs, labels, 8.23-5 radiation alarm signals, other access controls, and re-quired Notices to Employees, copies of licenses, and otiier items are properly posted, legible, and opera-tive, as required by 10 CFR Part 19, "Notices, In-structions and Reports to Workers; Inspections,'" and Part 20 or by license conditions.

Radiation alarm sig-nals should be routinely tested for operation by use of appropriate check sources to ensure proper function-ing of the alarms. Microswitches on which these in-struments depend for operation should also be tested to ensure that they will function reliably in normal operations or as expected under emergency condi-tions. Care should be taken to minimize exposure to personnel from the tests themselves.

Any signs, labels, or notices found to be missing should be promptly provided.

Temporary signs, signals, or bar-riers, together with appropriate worker notification and instruction, may be used in the interim when items specified in Parts 19 and 20 are not available, but acceptable corrections should be provided as soon as practicable.

1.11 Leak Tests of Sources Sealed sources containing (a) more than 100 mi-crocuries of a byproduct material with a half-life of more than 30 days (except iridium-192 seeds encased in nylon ribbon) (see paragraph

35.14(b)(5))

or (b)more than 10 microcuries of an alpha emitter (see paragraph

31.5(b)(2)(ii))

must be leak tested for con-tamination or leakage at intervals not to exceed 6 months unless a different interval is specified for a particular manufactured source under the provisions of paragraph

32.74(b) of 10 CFR Part 32, "Specific Domestic Licenses to Manufacture or Transfer Cer-tain Items Containing Byproduct Material." Further provisions and exceptions to leak-testing require-ments are established in paragraphs

35.14(b) and 35.14(e)(1)

of 10 CFR Part 35. Any specific license conditions must also be followed.1.12 Calibration and Source Checks of Radiation Safety Instruments Portable survey instruments should be calibrated at least annually to within +/-1 0 percent (or _+/-20 percent with a calibration curve supplied)

of two points (at a minimum) at approximately

1/3 and 2/3 of each scale in order to examine readability, operability, and ac-curacy. Instruments should be calibrated with radia-tion sources of appropriate emission and intensity.

Each source used for calibration should be certified in radioactivity content to within 15 percent by the supplier, as recommended by the International Com-mission on Radiological Units and Measurements (Ref. 15), and should be corrected for decay as of the day on which the source is used for survey instrument calibration.

All decay corrections should be included in the radiation safety records system. A posted graph for each source is convenient, helpful in avoiding calculational errors, easily available for inspection, and acceptable for obtaining source intensity within the required accuracy.A calibration should be performed after each maintenance adjustment or repair, and no less fre-quently than at 12-month intervals, by exposing the instrument to an appropriate field of radiation and checking the response of the instrument at a minimum of two points near '/3 and 2/3 of full scale.The readings obtained from the calibration verifica-tion should be recorded, preferably by plotting the reading on the instrument calibration curve where ap-plicable.

Other instruments should be calibrated at frequencies suggested by the manufacturer.

Check sources should be used to check the continued accu-racy of all instruments each time they are used in the field, preferably before and after each series of meas-urements. (See also Regulatory Guide 10.8., "Guide for the Preparation of Applications for Medical Pro-grams. ")1.13 Surveys of Protective Clothing Before and After Laundry Surveys of protective garments and linens should be performed prior to release to a conventional laun-dry'. Garments and linens should be released to such a laundry only if contamination levels do not exceed those given on line 3 of Table 2. Items contaminated with short-half-life material that exceeds the levels given on line 3 of Table 2 should be contained in leakproof bags arld transported in carts to controlled storage areas for decay'. Items contaminated with long-half-life material may be disposed of as radioac-tive waste or sent for decontamination to a laundry licensed by the NRC or by an Agreement State.1.14 Ventilation Surveys Where enclosures such as fume hoods are used to protect workers from unencapsulated radioactive material, measurements of the face velocity at the en-closure entrance should be made and recorded quar-terly to ensure that the airflow is adequate.3 Such measurements should be made by using a properly calibrated thermoanemometer or velometer to deter-mine whether the airflow has been reduced to unac-ceptable levels by filter loading or by the malfunction of blowers, fans, etc. The minimum average face velocity for a fume hood with the sash in the operat-I Where filtered exhausts are employed, devices such as U-tube manometers should be provided to indicate the pressure drop across the filters, thus affording an early indication of airflow loss at enclosures.

8.23-6 ing position or for an opening in a special enclosure should be 100 ft/min, as determined from at least five different measurement points. Corrective action should be taken as soon as possible when the face velocity is found to be deficient.

1.15 Surveys in In-Hospital Unrestricted Areas Unrestricted areas should be surveyed periodically to ensure that radiation and radioactive material are adequately confined in restricted areas, except in cases where these materials must be transported be-tween areas. Recommendations in References I1 and 12 should be followed when transporting radioactive materials or patients emitting radiation from licensed radioactive materials through hallways or other unre-stricted areas of the hospital.

Such transportation should be surveyed and planned with a member of the radiation safety staff.1.15.1 Surface Contamination Surveys Removable surface contamination surveys in un-restricted areas in which unencapsulated radioactive materials are used or where contamination may be likely to occur should be performed and recorded at frequencies consistent with the potential for spreading contamination but no less frequently than quarterly.

Random smear testing of floors alone is acceptable for most unrestricted areas. In cafeterias and snack bars, furniture and equipment, as well as floors, should also be surveyed.

If such surveys reveal that radioactive contamination is being transferred out of restricted areas, immediate corrective action should be taken to eliminate such transfers.

Decontamination efforts should be repeated until it is evident that subsequent efforts would not significantly reduce contamination levels. If contamination is found, unrestricted areas should be surveyed more frequently (e.g., daily or weekly) until a trend of negative results is again es-tablished.

The applicant or licensee may propose and justify permissible contamination levels, following de-contamination efforts described above, for unrestricted areas. The limits given on line I of Table 2 are accept-able to the NRC staff and need not be justified by the licensee or applicant.

1.15.2 Radiation Surveys Radiation surveys in unrestricted areas adjacent to restricted areas should be performed and recorded at frequencies consistent with the types and quantities of material in use but no less frequently than quarterly.

These surveys should be made in areas adjacent to re-stricted areas and, when exposures may occur, in all areas through which radioactive materials are trans-ferred and temporarily stored before shipment.

Radia-tion levels in these areas should be evaluated to deter-mine whether they comply with the requirements of§20.105 of 10 CFR Part 20.1.16 Surveillance

1.16.1 Surveillance by Individual Performing Surveys The term "surveillance," as used in this sec-tion, refers to observations of radiological working conditions in restricted areas made by the person who performs the routine radiation and contamination sur-veys. Such surveillance is one of the more important aspects of a radiation protection program. Through surveillance, radiation safety personnel acquire de-tailed knowledge of each operation as necessary (a)to identify ways of preventing or minimizing occupa-tional exposures, (b) to select appropriate times for making radiation safety measurements, and (c) to adequately prepare for emergency conditions.

Radia-tion safety personnel should be sufficiently familiar with each activity to explain it in detail, to describe potential hazards and the precautions taken to minimize exposures, and to discuss how this knowl-edge of procedures within each activity has influ-enced the selection of appropriate times for perform-ing radiation safety measurements.

1.16.2 Regular Inventory of Radioactive Mate-rial, Audit of Procedures, and Instruc-tion of Personnel The surveillance program includes: a. Regular inventory of radioactive materials and their locations, b. Frequent audits of radiation safety procedures and the uses and amounts of material in process com-pared to licensed possession limits, and c. Discussions with personnel to ensure their continued awareness of safety procedures and the ap-propriateness of their instruction and training for the tasks they are performing.

These surveillance activities may be performed during the performance of other survey measurements or tests. The surveillance should be performed at least annually by the Radiation Safety Officer, in the presence of a management representative, as a man-agement audit. The management audit should be comprehensive enough to provide management with an awareness of the nature and importance of ac-tivities conducted for personnel protection and hos-pital safety. A sample checklist that can be useful in auditing as well as in carrying out radiation surveys is presented in Appendix B.8.23-7

2. Frequency of Surveys The frequency of routine surveys depends on the nature, quantity, and use of radioactive materials, as well as the specific protective facilities, equipment, and procedures that are designed to protect the worker from external and internal exposure.Generally, surveys should be performed before radioactive materials are used in a new procedure and area in order to establish a baseline of background radiation levels and radioactivity from natural sources, including structural components of the facil-ity, and any already existing operations with radia-tion sources in nearby rooms or facilities.

These baseline surveys should be performed under the vari-ous conditions to be expected in routine hospital pro-cedures.Surveys should be repeated after routine proce-dures begin with normal levels of radioactive material and with potentially exposed persons present and car-rying out their functions.

Surveys should also be conducted after significant changes in the quantities of radioactive material handled or in the quantities present at any one time or after changes in protective equipment or procedures.

Although the frequencies of routine surveys de-pend on many factors, as stated above, and should be designed for the specific medical practices and facilities involved to maintain exposures as low as is reasonably achievable (ALARA), minimum fre-quencies acceptable to the NRC staff for meeting the requirements of §20.201 of 10 CFR Part 20 are given in Table I of this guide.3. Records of Surveys Referenice should be made to §§20.401 and 30.51 and to 10 CFR Parts 31-35 for recordkeeping re-quirements regarding surveys related to the receipt, use, packaging, transfer, and disposal of byproduct material.

Section 20.401 requires that licensees main-tain records in the same units used in Part 20. Thus, external exposure rates should be recorded in esti-mated maximum dose equivalent units to relevant parts of the body as specified in Part 20. Air concen-tration measurement results should be recorded in units of uCi/ml, and surface contamination meas-urement results should be recorded in units of dpm/100 cm 2 or tkCi/100 cm 2 (or as in §20.5).Record retention requirements are specified in the regulations cited abov

e. Paragraph

20.401(c)(2)

re-quires that survey records be preserved for 2 years, except that records of air monitoring and (in the ab-sence of personnel monitoring data) records of sur-veys to determine external radiation dose (see para-graph 20.401(c)(2)(ii))

are to be maintained until the NRC authorizes their disposition.

Records may be maintained in logbooks or on spe-cial forms as long as they are clear, legible, under-standable, and authenticated by authorized personnel.

The signature of the person making the record and the date should be on the same page as the record and should immediately follow each record entry. Either the original or a reproduced copy or microform (duly authenticated)

may be maintained to meet the storage requirements of §20.401.

D. IMPLEMENTATION

The purpose of this section is to provide informa-tion to applicants and licensees regarding the NRC staff's plan for using this regulatory guide.Except in those cases in which the applicant or licensee proposes an acceptable alternative method for complying with specified portions of the Com-mission's regulations, the staff will use the methods described herein after October 1, 1979, in evaluating applications for specific materials licenses for medi-cal institutions or (in conjunction with inspections of performance)

for evaluating survey programs estab-lished by licensees.

If an applicant or licensee wishes to use the method described in this regulatory guide on or before Oc-tober 1, 1979, the pertinent portions of the applica-tion or the licensee's performance will be evaluated on the basis of this guide.8.23-8 TABLE I SURVEY FREQUENCIES

1. All elution, preparation, and injection areas should be surveyed daily with a survey meter and decontami- nated if necessary.

2. Laboratory areas where only small quantities of radioactive material (less than I millicurie)

are used should be surveyed monthly.3. All other laboratory areas should be surveyed weekly.4. The weekly and monthly surveys should consist of: a. A measurement of radiation levels with a survey meter sufficiently sensitive to detect 0.1 mR/h.b. A series of smear tests to measure contamination levels. The method for performing smear tests should be sufficiently sensitive to detect the limits in Table 2 to one significant digit.c. Any air sample measurements necessary to determine compliance with §20.103 of 10 CFR Part 20 in cases where calculations alone are not sufficient.

TABLE 2 LIMITS FOR REMOVABLE

SURFACE CONTAMINATION

IN MEDICAL INSTITUTIONS*

Type of Radioactive Material**

Type of Surface Alpha Emitters Beta or X-Ray Emitters Low-Risk Beta or X-Ray (/xCi/cm 2) (,Ci/cm 2) Emitters (,Ci/cm 2)1. Unrestricted areas 10-1 10-6 10-5 2. Restricted areas 10-6 10-5 10-4 3. Personal clothing worn 10.1 10-6 10-5 outside restricted areas 4. Protective clothing worn 10.6 10-1 10-4 only in restricted areas 5. Skin 10-6 10-6 10-s* As adapted from Table I of Reference

4. Averaging is acceptable over inanimate areas of up to 300 cm2 or, for floors, walls, and ceiling, 100 cm 2.Averaging is also acceptable over 100 cm 2 for skin or, for the hands, over the whole area of the hand, nominally

300 cm 2.** Beta or x-ray emitter values are applicable for all beta or x-ray emitters other than those considered low risk. Low-risk nuclides include C-14, H-3, S-35, Tc-99m, and others whose beta energies are <0.2 MeV maximum, whose gamma or x-ray emission is less than 0. 1 R/h at 1 meter per curie, and whose permissible concentration in air (see 10 CFR Part 20, Appendix B, Table I) is greater than 10-6 pbCi/ml.8.23-9 REFERENCES*

I National Commission on Radiological Protection (NCRP) Report No. 8, "Control and Removal of Radioactive Contamination in Laboratories," is-sued December 15, 1951.2. NCRP Report No. 9, "Recommendations for Waste Disposal of Phosphorus-32 and Iodine-131 for Medical Users," issued November 2, 1951.3. NCRP Report No. 10, "Radiological Monitoring Methods and Instruments," issued April 7, 1952 (revised edition to be published in 1978).4. International Atomic Energy Agency (1AEA)Technical Report Series No. 120, "Monitoring of Radioactive Contamination on Surfaces." 1970.5. IAEA Safety Series No. 38, "Radiation Protec-tion Procedures,~

1973.6. IAEA Safety Series No. I, -Safe Handling of Radionuclides,'" 1973 Edition, Code of Practice Sponsored by the International Atomic Energy Agency (IAEA) and the World Health Organiza-tion (WHO), 1973.7. IAEA Technical Report Series No. 133, "Hand-book on Calibration of Radiation Protection Monitoring Instruments," 1971.IAEA reports may be obtained from UNIPUB. Inc.. P.O. Box 433, New York. N.Y. 10016.ICRP reports may be obtained from Pergamon Press, Maxwell House. Fairview Park. Elmsford, New York 10523.ICRU reports may be obtained from ICRU Publications, P.O.Box 30165, Washington.

D.C. 20014.NCRP reports may be obtained from NCRP Publications.

P.O.Box 4867, Washington, D.C. 20014.8. IAEA Safety Series No. 25, "Medical Supervi-sion of Radiation Workers,"'

sponsored jointly by IAEA. WHO, and ILO, 1968.9. International Commission on Radiological Pro-tection (ICRP) Publication

12, "General Princi-ples of Monitoring for Radiation Protection of Workers," Pergamon Press, 1969.10. AAPM Monograph No. 1, "Biophysical Aspects of the Medical Use of Technetium-99m," J. G.Kereiakes and Karen R. Corey, Editors (available from American Association of Physicists in Medicine, Dr. James G. Kereiakes, E555 Medi-cal Sciences Building, University of Cincinnati, Cincinnati, Ohio 45267), 1976.11. NCRP Report No. 48, "Radiation Protection for Medical and Allied Health Personnel," issued August 1, 1976.12. NCRP Report No. 37, "Precautions in the Man-agement of Patients Who Have Received Therapeutic Amounts of Radionuclides," 1970.13. Diegl, H., Guidelines for Determining Fre-quency of Wipe Samples,'

in Health Physics Operational Moniloring, Vol. 1, C. A. Willis and J. S. Handloser, Eds., Gordon and Breach.New York, 1972.14. Sommers, J. F., "Sensitivity of G-M and Ion Chamber Beta-Gamma Survey Instruments,

Health Physics 28, 755, 1975.15. International Commission on Radiation Units and Measurements (ICRU) Report 12, "Certification of Standardized Radioactive Sources,

Sep-tember 15, 1968.8.23-10

APPENDIX A SURVEYS OF RADIOACTIVE

XENON-133 RELEASES Surveys associated with the use of xenon-133 should be sufficient to show compliance with re-quirements for protection of persons in restricted and unrestricted areas (see §§20.103 and 20.106) and with the terms and conditions of the NRC Materials License. Surveys may consist of either measurements of airborne radioactivity or of calculations supported by records of xenon-133 used and measurements of pertinent ventilation and air effluent volumes. The procedures outlined below are acceptable for survey-ing xenon-133 concentrations in medical institutions.

Acceptable surveys would be indicated by records of the following information, procedures, or condi-tions: 1. Quantities Used a. Verify that patient information records (Items 1-3 below) are in order; compare with similar infor-mation submitted to NRC in support of request for xenon- 133.(1) Number of studies per week.(2) Activity administered to each patient.(3) Comparison of number of studies and aver-age activity administered to each patient with infor-mation submitted in application.

b. Verify that possession limits are controlled and corrected for differences in calibration date and date of use. Compare with license condition.

2. Survey Records for Use and Storage Areas Check ventilation quarterly in all areas in which xenon-133 is to be used and stored to ensure that all airflow rates are maintained in accordance with statements made in the license application.

3. Procedures for Routine Use a. Check to determine that procedures being fol-lowed for routine use of xenon-133 are in accordance with procedures described in license application.

Check to determine that all personnel using xenon-133 have been trained in these procedures for routine use of xenon-133.

b. Check to determine that special apparatus for administration and collection of xenon-133 is being used, as specified in the license application.

c. Check to determine that special procedures are being used to reduce leakage (e.g., use of nose champs or special enclosures), as specified in the license application.

4. Emergency Procedures Check to determine that all personnel using xenon-133 have been trained in the established emer-gency procedures to be followed in case of an acci-dental release of xenon-133.

5. Air Concentrations of Xenon-133 in Restricted Areas Check to determine that air concentrations of xenon-133 in restricted areas meet the requirements of §20.103. This may be done by making physical measurements.

Alternatively, this may be done by reviewing the use of xenon-133 (Item l.a above), checking the ventilation rate in each area, and per-forming calculations similar to those submitted with the license application.

If the results of the calcula-tions indicate that air concentrations of xenon-133 (as averaged over one calendar quarter) approach or ex-ceed 1 x 10-1 microcuries per milliliter, then the licensee should consider and implement methods of increasing ventilation rates or of reducing patient load.6. Methods of Xenon-133 Disposal a. Dilution through .exhaust systems Licensees who dispose of xenon-133 by release to the atmosphere through an air exhaust system are required to perform surveys (i.e., measurements or calculations)

to ensure that they are in compliance with paragraph

20.1(c) and §20.106 of 10 CFR Part 2

0. Paragraph

20.1 (c) requires that the concentrations of xenon-133 in effluents to unrestricted areas be as low as is reasonably achievable by the current state of technology, and §20.106 requires that the concentra- tions averaged over a period of 1 year should not ex-ceed 3 x 10-7 microcuries per milliliter.

Make physical measurements to determine com-pliance with §20.106 and paragraph

20.1(c). Alter-natively, measure ventilation rate and, using xenon-133 data from Item L.a above, perform calculations similar to those submitted with license application.

If the results indicate that air concentrations of xenon-133 (as averaged over 1 year) approach or ex-ceed 3 x 10' microcuries per milliliter, then the licensee should consider and implement methods of increasing ventilation rates, reducing patient load, or decreasing amount of xenon-133 released (e.g., through use of a charcoal trap).8.23-11 If the exhaust is released to a restricted area, e.g.. a roof to which access is controlled, or from a tall stack, Sutton's equation (Refs. 1 and 2) may be used to calculate the concentrations at the nearest unrestricted area. If this approach is used, record the location of the exhaust system outlet as used for the calculation model, including proximity to unre-stricted areas, air intakes, and open windows.b. Adsorption onto charcoal traps Surveys should be made to check leakage from charcoal trapping devices. If the exhaust is vented to the outdoors or other unrestricted area, check to de-termine that air concentrations of xenon-133, aver-aged over 1 year, do not -approach or exceed 3 x 10-1 microcuries per milliliter.

See Item 6.a above.Record measurements to check the performance of collection and trapping devices according to spec-ifications, both initially and on a continuing basis.Include monitoring of traps to determine when sat-uration occurs and when the filter must be replaced.Check the procedures for handling saturated fil-ters, including the provisions of adequate shielding and ventilation.

Calculations should be made of aver-a2e concentrations of xenon-133 in air at the exhaust and compared to the allowable limi

t. USEFUL CONVERSIONS

1 mCi 103 'uCi 1 ft 3 = 2.832X10-2 m 3= 2.832x10 4 mI 1 ft 3/min = 1.699X 106 mi/h= 6.797x 10' ml/40-h week= 1.484X 10 1 0 ml/yr I week = 168h REFERENCES

1. Blatz, Hanson, "Radiation Hygiene Handbook," McGraw-Hill, New York, 1959, pp. 22-7.2. Cember, Herman, 'Introduction to Health Physics," Pergamon Press, New York, 1969, pp.334-9..23-12 APPENDIX B SAMPLE CHECKLIST

FOR RADIATION

SURVEYOR I. Initiate contamination survey report for each lab a. Check card for previous survey results, e.g., successive red circles, nobody in.b. Fill in name on Authorized User, Department, Building and Room Number, and Survey Date.c. Sketch floor plan.2. Ask lab personnel (and record answers on report form)a. What isotopes are being used? (Compare with what User is cleared for.)b. Where in the lab are they used?c. Where are isotopes stored?d. What was last order? (Compare with card record.)e. Is Authorized User available, if needed? If not, give reason, e.g., on leave, out of country, terminated employment.

f. In what other labs are isotopes used? (Compare with card record.)g. Where is waste stored and disposed of?3. Check labeling a. Lab door--"Caution, Radioactive Material' (CRM).b. Liquid waste sink--"Contaminated Liquid Waste" (survey card should indicate radioactive sink-RS).Is sink log posted? Is it being used?c. Radioactive hood-"Caution, Radioactive Material" (survey card should indicate radioactive hood-RH). "Air Flow Check" white label with date no older than 1 year required.d. Refrigerator and other storage areas-'"CRM,'" including those in corridors.

e. Radioactive waste containers--"CRM'" or "Contaminated Waste" should be lined with yellow plastic bag.f. Any area with external radiation over 2.5 mR/h should be labeled with "Caution, Radiation Area" (CRA) and should be noted on survey form. (See paragraph

20.202(b)(2)

and §20.203 of 10 CFR Part 20.)2. 10 CFR Part 19 signs.4. Observe general laboratory conditions a. Food and drink preparation and use in radioactive material areas.b. Waste container overfilled.

c. Dosimeters being worn.d. Mouth pipetting.

5. Conduct laboratory survey using portable survey meter a. Record external dose rate from accessible storage surfaces.b. Record exposure rate from contaminated surfaces found.6. Smear survey a. Take first smear near or in lab entrance.b. Take several smears from floor and benches and equipment as indicated by answers to earlier questions.

7. Discuss 10 CFR Part 19 (Instruction to Workers) requirements.

8. Results a. Count smears and list results on survey form.b. Notifylab personnel of contamination, and note on form who was called and date of notification.

c. Identify all abnormal radiation safety conditions on survey form document.d. Complete survey card, replace in file, and mail survey form copy to User.e. If lab has contamination (significant), call User, request cleanup, and resmear.f. Do resmear when notified or call User if no resmear was called for.g. File carbon copy of results form.8.23-13 UNITED STATES NUCLEAR REGULATORY

COMMISSION

POSTAGE WASHINGTON, D. C. 20555 U.S. NUCLE CO OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, $300 120555011962

1 SO US NRC.Or:FICE OF THE COMMISSIONERS

OR .JOSEPH HENDRIE CHAIRMAN H1149 WASHINGTON

DC 20 E AND FEES PAID EAR REGULATORY

'MMISSION 555