U.S. NUCLEAR REGULATORY COMMISSION February 1979

REG ULATO RY G U [ D 0j"EOFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 8.23RADIATION SAFETY SURVEYS AT MEDICAL INSTITUTIONS

A. INTRODUCTION

Paragraph 20.201(b) of 10 CFR Part 20, "Stand-ards for Protection Against Radiation," requires thateach licensee make or cause to be made such surveysas may be necessary for him to comply with the regu-lations in Part 20. As used in Part 20, the term "sur-

Surveyst are a necessary supplement to personnelmonitoring, 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'Žs icenseod by the NRC should havethat 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'stive materials for purposes of diagnosis, therapy, or usei dioa&1tie 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 airbornetaining 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 releasedtion 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 publicmethods acceptable to the NRC staff of implementing specific parts of theCommission's regulations, to delineate techniques used by the staff in evalu-ating specific problems or postulated accidents, or to provide guidance toapplicants. Regulatory Guides are not substitutes for regulations, and com-pliance with them is not required. Methods and solutions different from thoseset out in the guides will be acceptable if they provide a basis for the findingsrequisite to the issuance or *continuance of a permit or license by theCommission.Comments and suggestions for improvements in these guides are encouragedat all times, and guides will be revised, as appropriate, to accommodate com-ments and to reflect new information or experience. However, comments onthis guide, if received within about two months after its issuance, will beparticularly useful in evaluating the need for an early revision.

Comments should be sent to the Secretary of the Commission, U.S. NuclearRegulatory Commission, Washington, D.C. 20555, Attention: Docketing andService Branch.

The guides are issued in the following ten broad divisions:

1. Power Reactors 6. Products2, Research and Test Reactors 7. Transportation3. Fuels and Materials Facilities 8. Occupational Health4. Environmental and Siting 9. Antitrust and Financial Review5. Materials and Plant Protection 10. General

Requests for single copies of issued guides (which may be reproduced) or forplacement on an automatic distribution list for single copies of future guidesin specific divisions should be made in writing to the U.S. Nuclear RegulatoryCommission, Washington, D.C. 20555, Attention: Director, Division ofTechnical Information and Document Control.

Part 20. In many medical institutions, surveys ofeffluents or calculations to ensure that permissibleconcentration limits are not exceeded are included asa regular part of the health physics survey program.Often these calculations may be made by estimatingthe amounts of radioactive material washed down des-ignated sinks and dividing them by the quantities of

sewage released from the hospital, as indicated on thehospital's water or sewage bills. This procedure nor-mally suffices to show compliance with the effluentlimits 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 maysometimes be estimated by calculational techniques ifnot by air-monitoring procedures. Appendix A to thisguide 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 ExposureLevels

Areas to be surveyed should include any locationswhere individuals may.be exposed to radiation inten-sities that might cause the occupational radiation doseto exceed 10 percent of the limits of paragraph20.101(a) in any calendar quarter or where an indi-vidual is working with any radiation source that couldproduce radiation levels greater than 1.0 mR/h at 1meter. These areas typically include shipping and re-ceiving areas; isotope laboratories in nuclearmedicine; diagnostic areas in nuclear medicine; in-tracavitary source preparation areas in radiation ther-apy; patients' rooms where treatments are given withintracavitary, interstitial, or radiopharmaceuticaltherapy 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 mightbe exposed (e.g., areas occupied by technologists,nursing staff, visitors, patients, or any other personswho may be exposed to radioactive materials handledby others).

Preoperational, routine, and special surveys ofthese 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 instituteand maintain a program of surveys performed byworkers other than health physics personnel who maybe 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 conductingsuch surveys and should perform the surveys eachday during and after work with radioactive materials,as necessary to determine the need to limit worktimeand to use protective procedures to reduce exposuresas far below the paragraph 20. 101(a) limits as is rea-sonably achievable. The survey results obtained bythese workers need not be recorded. However, theRadiation Safety Office should maintain records toshow 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 compliancewith the personnel monitoring requirements of§20.202. However, in the event of accidental loss ofpersonnel dosimetry data, e.g., as a result of losingthe dosimeter or chemical or physical damage to thedosimeter, the best alternative means of estimatingthe exposure may be to use survey data in conjunc-tion with appropriate occupancy factors. In suchcase, the estimate, including the survey data used,should be documented and retained indefinitely (seeparagraph 20.401(c)(2)(ii)). Survey results should

be reviewed carefully by the Radiation Safety Officerto 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 toshow by calculation, together with monitoring of ven-tilation rates, that air concentrations are well belowlevels that would require routine air sampling. How-ever, concentrations of radioactive material in airshould be measured, at frequencies specified in Sec-tion C.2. for areas where operations could exposeworkers to 10 percent or more of the concentrationvalues given in Table 1, Column 1, of Appendix B to10 CFR Part 20. Special requirements for suchmonitoring may also be made a condition of thelicense.

Air samples obtained in accordance with §20.103should be representative of the air in the workers'breathing zone. In cases where breathing zone sam-pling is not accomplished, air samples taken outsidethe breathing zone closer to the source, where theconcentration of radioactive material can or is ex-pected to be equal to or greater than the concentrationin the breathing zone, are acceptable. When measur-ing the quantity of radioactive material deposited onan air sample filter, corrections should-be made for

8. 2 3- 2

absorption of alpha or beta particles by the filtermedia and by material collected on the filter. Thequantity of air that has passed through the filtershould be accurately measured and corrections madefor any loss of flow rate due to the accumulation ofmaterial on the filter.

Continuous breathing zone or general air samplingshould be conducted while the work is in progressunless experience with sample results or calculationshas demonstrated that the concentration of radioac-tive material in the breathing zone is not likely toexceed 25 percent of the values given in Table 1,Column 1, of Appendix B to 10 CFR Part 20. Theuse of personal (lapel) samplers is acceptable forbreathing zone sampling. If the air sampling is notcontinuous, the frequency and the times selected forthe sampling should be based on the nature of theprocess involved and the probability that airborneradioactive material will be present. When assessingthis probability is difficult, frequencies based on in-formation given in Section C.2 and Table I of thisguide are acceptable.

1.4 Surface Contamination Surveys

Regular surveys for radioactive contamination thatcould 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 accordancewith 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 tolimit external dose rates and the resuspension of looseradioactive materials that may enter the body throughinhalation, ingestion, or skin absorption.

1.4.1 Removable Contamination

For the purposes of this guide, removable con-tamination means radioactivity that can be transferredfrom a surface to a smear test paper by rubbing withmoderate pressure. Information is available on theselection and use of instruments for performing re-movable surface contamination surveys appropriate tothe radionuclides used in medical institutions (Refs.1-14). Methods and instruments used in surfacecontamination surveys should be sufficiently sensi-tive to detect the nuclides being monitored (Refs.11-14). For optimum detection of low-energy betaemitters (e.g., H-3 and C-14) as well as of alphaemitters and low-energy x- or gamma-ray emitters(e~g., 1-125), liquid scintillation counting or internalproportional counting is normally necessary with theuse 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 grosscontamination levels are not already too high forcounting with sensitive equipment, (b) to minimize(in some cases) the chance for inadvertent, spread ofcontamination by the contamination survey or otheractivities to be performed in the meantime, and (c) todetermine which areas require greater attention insmear testing. The instrument used for this purposeshould have a short time constant on the order of 1second or less to facilitate detection.

A standardized method for smear testing of arelatively uniform area should be used in order toallow comparison of relative levels of contaminationat different times and places. A dry smear taken froman area of about 100 cm 2 is acceptable to indicatelevels of removable contamination.

A layout diagram for each laboratory routinelysurveyed is helpful for recording survey results in auniform manner to aid review and observation oftrends and for satisfying regulatory requirements foravailability of survey records. On these diagrams, itis helpful to specify key locations that are smeartested 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 instrumentsused in the survey and in counting the smearsamples,

c. Disintegration rate of each instrument test orcalibration source,

d. Sample, backgrbund, and test counts andtimes, and

e. Signatures at the bottom of each page.

Provision should also be made on the diagram forrecording an instrument check with an appropriatecheck or calibration source for each batch of smearsamples counted.

The surveys discussed above are regularlyscheduled and recorded on the survey diagrams. Inaddition, it may be necessary to conduct more fre-quent, informal, and unrecorded surveys in nuclearmedicine areas or other areas where loose radioactivecontamination may occur. Such surveys can be madewith a thin-end-window (less than 2 mg/cm 2) detectorheld close to a smear sample immediately after it istaken in the working area. When ambient externalradiation levels in the laboratory are low enough tomaintain external radiation exposures below the lim-

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its of paragraph 20.101(a), any appreciable surfacecontamination can be detected by simply holding thedetector in a fixed position and moving the smearsample close to and away from the detector severaltimes. This method may be used for the vast majorityof radionuclides used in diagnostic and therapeuticmedical practice.

Part 20 does not specify limits for surface con-tamination. Each applicant may propose and justifywhat removable surface contamination limits will beallowable before decontamination will be performed.These limits should be based on the need to avoidtransfer of si2nificant amounts of contamination tounrestricted areas and to maintain exposures as lowas is reasonably achievable. The contamination limitsfor restricted areas presented on line 2 of Table 2 ofthis guide are acceptable to the NRC staff and neednot 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 afterrepeated decontamination attempts fail to signifi-cantly reduce the contamination level. A total con-tamination survey, using instruments suitable for theradionuclides 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 restrictedand unrestricted areas before decontamination will beperformed. The limits appearing on line 2 of Table 2,multiplied by a factor of 5, are acceptable to the NRCstaff and need not be justified by the licensee orapplicant.

1.5 Protective and Personal Clothing Contamina-

tion Surveys

Individuals working in areas where a potential forskin or clothing contamination exists should be pro-vided with suitable protective clothing. Laboratorycoats and protective gloves, as described in Refer-ences 11 and 12, are usually adequate for any proce-dures in medical institutions. Protective clothingshould be surveyed by the wearer after use if signifi-cant contamination is possible. Contaminated protec-tive clothing should be removed and placed in speciallaundry containers before leaving a restricted workarea. Disposable gloves should be discarded inradioactive waste containers. After gloves are re-moved, hands should be washed and surveyed.

When protective clothing contamination levels maybe expected to exceed preselected limits, workersshould be instructed to take care to avoid dispersal ofcontamination and to report the situation to the Radia-

tion Safety Office. A member of the radiation safetystaff should then survey and supervise any necessarydecontamination 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 bythe licensee or applicant.

Contamination levels observed and procedures fol-lowed during survey and decontamination of personalclothing should be recorded. The written recordshould include the names of persons surveyed, a de-scription of prior work activities, the probablecauses, 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 beroutinely recorded unless the limits on line 4 of Table2 are exceeded. The radiation safety staff shouldconduct spot-checks monthly to ensure that the work-ers continue their own personal contamination sur-veys.

In restricted areas with little potential for surfacecontamination, personal clothing is often worn be-neath protective clothing. Such personal clothingshould be surveyed by the wearer before he or sheleaves the restricted area. (However, this is neitherpracticable nor necessary for employees working with

only microcurie quantities of tritium or carbon-14.)Workers should be instructed to report the situation tothe Radiation Safety Office when personal clothingcontamination levels exceed preselected limits. Amember of the radiation safety staff should then sur-vey and supervise any necessary decontamination orclothing 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 theapplicant or licensee. Records should be maintainedin the same manner as those for protective clothingcontamination.

1.6 Personal Surveys

Although personal contamination in excess of thevalue given on line 5 of Table 2 is unusual in medicalinstitutions, individuals who work in restricted areasunder 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 tothe body, hair, bottoms of the shoes or feet, and thehands. Workers should be instructed to report the de-tection of contamination on the body to the RadiationSafety Office. Decontamination attempts, under thedirection of Radiation Safety Office personnel or a

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medical consultant, should be repeated until (a) suchattempts cease to effect significant reductions or (b)such attempts threaten to irritate or harm the skin .2

When decontamination attempts are terminated, thereshould .be no further concern if the residual contami-nation does not exceed preselected levels. Such levelsmay be proposed and justified by the applicant orlicensee. The limits given on line 5 of Table 2 will beaccepted without justification. If residual contamina-tion exceeds the selected limits, the affected indi-vidual may be released (since his contamination isnow relatively fixed and not likely to enter the body),but periodic surveys should be made until the limitsare no longer exceeded. The resulting dose should bedetermined and entered in the individual's personneldosimetry record. Complete records should be main-tained of each incident of this nature.

Since medical personnel may often handle openvials or containers with millicurie or higher levels ofvolatile 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, bioassaymonitoring is sometimes made a condition of thelicense. Acceptable criteria for such programs arepublished in other guides and are available from theLicense Management Branch. In addition to theseprograms, placing the detector against the neck closeto the thyroid is often useful for monitoring for inter-nal deposition of these nuclides during surveys forskin contamination; however, for 1-125 a thin crystalscintillation probe would be needed to obtainadequate sensitivity. In this way, appropriate person-nel may be more frequently monitored for internalexposure while they are also being monitored for ex-ternal contamination. Any positive indications fromthese types of surveys should be recorded in the radi-ation safety logs. Indications of internal depositionsshould 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 contaminationsurveys should be conducted on such instruments andequijment 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 properlyinstructed in applying them. If such attempts do not reduce thecontamination to acceptable levels, the aid of the licensee'smedical 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 proposeand justify total and removable contamination limitsbelow which uncontrolled release of equipment ispermitted. The limits given in Table I of RegulatoryGuide 1.86. "Termination of Operating Licenses forNuclear Reactors,'" are acceptable to the NRC staffand need not be justified by the licensee or applicant.

1.8 IngestionSurveillance 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 inwork areas or while wearing potentially contaminatedclothing; storing foods in work areas; pipetting bymouth; and wearing contaminated laboratory coats tothe cafeteria or other unrestricted areas. Water foun-tains close to radioactivity work areas should besmear tested regularly.

1.9 Surveys of Packages Received and PackagesPrepared for Shipment

External radiation measurements and tests of ex-ternal surfaces of packages received or packaged forshipment should be carried out near the receiving orpackaging point to avoid unwarranted radiation expo-sures and inadvertent contamination of personnel orthe hospital. Surveys and labeling must comply withthe NRC's regulations (see §§20.203, 20.205, 32.19,and 32.70 through 32.74 of 10 CFR) and with anyspecific license conditions. Delivery of packageswithin the hospital should also be monitored. Any de-livered containers of radioactive material must belabeled, as required by paragraph 20.203(f). Allpackages bearing yellow I or yellow III labels shouldbe transported by cart. Only adequately shieldedsources should be transported. Internal containers ofpackages containing significant amounts of radioac-tive materials should not be opened until the contain-ers have been placed in the appropriate protectivefacility (e.g., hood).

All personnel, including security guards, should beadequately instructed in performing at least an initialinspection survey for leakage, or damage, beforetransporting any packages of radioactive materialsthrough hospital areas. The instructions shouldclearly indicate which packages should be transportedby 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,

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radiation alarm signals, other access controls, and re-quired Notices to Employees, copies of licenses, andotiier items are properly posted, legible, and opera-tive, as required by 10 CFR Part 19, "Notices, In-structions and Reports to Workers; Inspections,'" andPart 20 or by license conditions. Radiation alarm sig-nals should be routinely tested for operation by use ofappropriate check sources to ensure proper function-ing of the alarms. Microswitches on which these in-struments depend for operation should also be testedto ensure that they will function reliably in normaloperations or as expected under emergency condi-tions. Care should be taken to minimize exposure topersonnel from the tests themselves. Any signs,labels, or notices found to be missing should bepromptly provided. Temporary signs, signals, or bar-riers, together with appropriate worker notificationand instruction, may be used in the interim whenitems specified in Parts 19 and 20 are not available,but acceptable corrections should be provided as soonas practicable.

1.11 Leak Tests of Sources

Sealed sources containing (a) more than 100 mi-crocuries of a byproduct material with a half-life ofmore than 30 days (except iridium-192 seeds encasedin nylon ribbon) (see paragraph 35.14(b)(5)) or (b)more than 10 microcuries of an alpha emitter (seeparagraph 31.5(b)(2)(ii)) must be leak tested for con-tamination or leakage at intervals not to exceed 6months unless a different interval is specified for aparticular manufactured source under the provisionsof paragraph 32.74(b) of 10 CFR Part 32, "SpecificDomestic Licenses to Manufacture or Transfer Cer-tain Items Containing Byproduct Material." Furtherprovisions and exceptions to leak-testing require-ments are established in paragraphs 35.14(b) and35.14(e)(1) of 10 CFR Part 35. Any specific licenseconditions must also be followed.

1.12 Calibration and Source Checks of RadiationSafety Instruments

Portable survey instruments should be calibrated atleast annually to within ±1 0 percent (or _±20 percentwith a calibration curve supplied) of two points (at aminimum) at approximately 1/3 and 2/3 of each scalein 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 inradioactivity content to within 15 percent by thesupplier, as recommended by the International Com-mission on Radiological Units and Measurements(Ref. 15), and should be corrected for decay as of theday on which the source is used for survey instrumentcalibration. All decay corrections should be included

in the radiation safety records system. A posted graphfor each source is convenient, helpful in avoidingcalculational errors, easily available for inspection,and acceptable for obtaining source intensity withinthe required accuracy.

A calibration should be performed after eachmaintenance adjustment or repair, and no less fre-quently than at 12-month intervals, by exposing theinstrument to an appropriate field of radiation andchecking the response of the instrument at aminimum 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 thereading on the instrument calibration curve where ap-plicable. Other instruments should be calibrated atfrequencies suggested by the manufacturer. Checksources should be used to check the continued accu-racy of all instruments each time they are used in thefield, preferably before and after each series of meas-urements. (See also Regulatory Guide 10.8., "Guidefor the Preparation of Applications for Medical Pro-grams. ")

1.13 Surveys of Protective Clothing Before andAfter Laundry

Surveys of protective garments and linens shouldbe performed prior to release to a conventional laun-dry'. Garments and linens should be released to such alaundry only if contamination levels do not exceedthose given on line 3 of Table 2. Items contaminatedwith short-half-life material that exceeds the levelsgiven on line 3 of Table 2 should be contained inleakproof bags arld transported in carts to controlledstorage areas for decay'. Items contaminated withlong-half-life material may be disposed of as radioac-tive waste or sent for decontamination to a laundrylicensed by the NRC or by an Agreement State.

1.14 Ventilation Surveys

Where enclosures such as fume hoods are used toprotect workers from unencapsulated radioactivematerial, 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 Suchmeasurements should be made by using a properlycalibrated thermoanemometer or velometer to deter-mine whether the airflow has been reduced to unac-ceptable levels by filter loading or by the malfunctionof blowers, fans, etc. The minimum average facevelocity for a fume hood with the sash in the operat-

I Where filtered exhausts are employed, devices such as U-tubemanometers should be provided to indicate the pressure dropacross the filters, thus affording an early indication of airflow

loss at enclosures.

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ing position or for an opening in a special enclosureshould be 100 ft/min, as determined from at least fivedifferent measurement points. Corrective actionshould be taken as soon as possible when the facevelocity is found to be deficient.

1.15 Surveys in In-Hospital Unrestricted Areas

Unrestricted areas should be surveyed periodicallyto ensure that radiation and radioactive material areadequately confined in restricted areas, except incases where these materials must be transported be-tween areas. Recommendations in References I1 and12 should be followed when transporting radioactivematerials or patients emitting radiation from licensedradioactive materials through hallways or other unre-stricted areas of the hospital. Such transportationshould be surveyed and planned with a member of theradiation safety staff.

1.15.1 Surface Contamination Surveys

Removable surface contamination surveys in un-restricted areas in which unencapsulated radioactivematerials are used or where contamination may belikely to occur should be performed and recorded atfrequencies consistent with the potential for spreadingcontamination but no less frequently than quarterly.Random smear testing of floors alone is acceptable formost unrestricted areas. In cafeterias and snack bars,furniture and equipment, as well as floors, should alsobe surveyed. If such surveys reveal that radioactivecontamination is being transferred out of restrictedareas, immediate corrective action should be taken toeliminate such transfers. Decontamination effortsshould be repeated until it is evident that subsequentefforts would not significantly reduce contaminationlevels. If contamination is found, unrestricted areasshould be surveyed more frequently (e.g., daily orweekly) until a trend of negative results is again es-tablished. The applicant or licensee may propose andjustify permissible contamination levels, following de-contamination efforts described above, for unrestrictedareas. The limits given on line I of Table 2 are accept-able to the NRC staff and need not be justified by thelicensee or applicant.

1.15.2 Radiation Surveys

Radiation surveys in unrestricted areas adjacent torestricted areas should be performed and recorded atfrequencies consistent with the types and quantities ofmaterial 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 allareas 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 PerformingSurveys

The term "surveillance," as used in this sec-tion, refers to observations of radiological workingconditions in restricted areas made by the person whoperforms the routine radiation and contamination sur-veys. Such surveillance is one of the more importantaspects of a radiation protection program. Throughsurveillance, 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 formaking radiation safety measurements, and (c) toadequately prepare for emergency conditions. Radia-tion safety personnel should be sufficiently familiarwith each activity to explain it in detail, to describepotential hazards and the precautions taken tominimize 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 andtheir locations,

b. Frequent audits of radiation safety proceduresand the uses and amounts of material in process com-pared to licensed possession limits, and

c. Discussions with personnel to ensure theircontinued awareness of safety procedures and the ap-propriateness of their instruction and training for thetasks they are performing.

These surveillance activities may be performedduring the performance of other survey measurementsor tests. The surveillance should be performed atleast annually by the Radiation Safety Officer, in thepresence of a management representative, as a man-agement audit. The management audit should becomprehensive enough to provide management withan awareness of the nature and importance of ac-tivities conducted for personnel protection and hos-pital safety. A sample checklist that can be useful inauditing as well as in carrying out radiation surveys ispresented in Appendix B.

8.23-7

2. Frequency of Surveys

The frequency of routine surveys depends on thenature, quantity, and use of radioactive materials, aswell as the specific protective facilities, equipment,and procedures that are designed to protect theworker from external and internal exposure.

Generally, surveys should be performed beforeradioactive materials are used in a new procedure andarea in order to establish a baseline of backgroundradiation levels and radioactivity from naturalsources, including structural components of the facil-ity, and any already existing operations with radia-tion sources in nearby rooms or facilities. Thesebaseline 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 materialand with potentially exposed persons present and car-rying out their functions. Surveys should also beconducted after significant changes in the quantitiesof radioactive material handled or in the quantitiespresent at any one time or after changes in protectiveequipment or procedures.

Although the frequencies of routine surveys de-pend on many factors, as stated above, and should bedesigned for the specific medical practices andfacilities involved to maintain exposures as low as isreasonably achievable (ALARA), minimum fre-quencies acceptable to the NRC staff for meeting therequirements of §20.201 of 10 CFR Part 20 are givenin Table I of this guide.

3. Records of Surveys

Referenice should be made to §§20.401 and 30.51and to 10 CFR Parts 31-35 for recordkeeping re-quirements regarding surveys related to the receipt,use, packaging, transfer, and disposal of byproductmaterial. 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 inunits of uCi/ml, and surface contamination meas-urement results should be recorded in units ofdpm/100 cm 2 or tkCi/100 cm 2 (or as in §20.5).

Record retention requirements are specified in theregulations cited above. 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 untilthe 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 thedate should be on the same page as the record andshould immediately follow each record entry. Eitherthe original or a reproduced copy or microform (dulyauthenticated) may be maintained to meet the storagerequirements of §20.401.

D. IMPLEMENTATION

The purpose of this section is to provide informa-tion to applicants and licensees regarding the NRCstaff's plan for using this regulatory guide.

Except in those cases in which the applicant orlicensee proposes an acceptable alternative methodfor complying with specified portions of the Com-mission's regulations, the staff will use the methodsdescribed herein after October 1, 1979, in evaluatingapplications for specific materials licenses for medi-cal institutions or (in conjunction with inspections ofperformance) for evaluating survey programs estab-lished by licensees.

If an applicant or licensee wishes to use the methoddescribed 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 evaluatedon the basis of this guide.

8.23-8

TABLE ISURVEY 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 shouldbe 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 besufficiently 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/cm2)

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 restrictedareas

4. Protective clothing worn 10.6 10-1 10-4

only in restrictedareas

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

cm2

. Averaging is also acceptable over 100 cm2 for skin or, for the hands, over the whole area of the hand, nominally 300 cm2 .** Beta or x-ray emitter values are applicable for all beta or x-ray emitters other than those considered low risk. Low-risk nuclidesinclude C-14, H-3, S-35, Tc-99m, and others whose beta energies are <0.2 MeV maximum, whose gamma or x-ray emission isless 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 ofRadioactive Contamination in Laboratories," is-sued December 15, 1951.

2. NCRP Report No. 9, "Recommendations forWaste Disposal of Phosphorus-32 and Iodine-131

for Medical Users," issued November 2, 1951.

3. NCRP Report No. 10, "Radiological MonitoringMethods and Instruments," issued April 7, 1952(revised edition to be published in 1978).

4. International Atomic Energy Agency (1AEA)

Technical Report Series No. 120, "Monitoringof Radioactive Contamination on Surfaces."1970.

5. IAEA Safety Series No. 38, "Radiation Protec-tion Procedures,~ 1973.

6. IAEA Safety Series No. I, -Safe Handling ofRadionuclides,'" 1973 Edition, Code of PracticeSponsored by the International Atomic EnergyAgency (IAEA) and the World Health Organiza-tion (WHO), 1973.

7. IAEA Technical Report Series No. 133, "Hand-book on Calibration of Radiation ProtectionMonitoring 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 byIAEA. WHO, and ILO, 1968.

9. International Commission on Radiological Pro-tection (ICRP) Publication 12, "General Princi-

ples of Monitoring for Radiation Protection ofWorkers," Pergamon Press, 1969.

10. AAPM Monograph No. 1, "Biophysical Aspectsof the Medical Use of Technetium-99m," J. G.Kereiakes and Karen R. Corey, Editors (available

from American Association of Physicists inMedicine, Dr. James G. Kereiakes, E555 Medi-cal Sciences Building, University of Cincinnati,Cincinnati, Ohio 45267), 1976.

11. NCRP Report No. 48, "Radiation Protection forMedical and Allied Health Personnel," issuedAugust 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. Willisand 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 andMeasurements (ICRU) Report 12, "Certificationof Standardized Radioactive Sources,'' Sep-tember 15, 1968.

8.23-10

APPENDIX ASURVEYS OF RADIOACTIVE XENON-133 RELEASES

Surveys associated with the use of xenon-133should be sufficient to show compliance with re-quirements for protection of persons in restricted andunrestricted areas (see §§20.103 and 20.106) andwith the terms and conditions of the NRC MaterialsLicense. Surveys may consist of either measurementsof airborne radioactivity or of calculations supportedby records of xenon-133 used and measurements ofpertinent ventilation and air effluent volumes. Theprocedures outlined below are acceptable for survey-ing xenon-133 concentrations in medical institutions.

Acceptable surveys would be indicated by recordsof the following information, procedures, or condi-tions:

1. Quantities Used

a. Verify that patient information records (Items1-3 below) are in order; compare with similar infor-mation submitted to NRC in support of request forxenon- 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 andcorrected for differences in calibration date and dateof use. Compare with license condition.

2. Survey Records for Use and Storage Areas

Check ventilation quarterly in all areas in whichxenon-133 is to be used and stored to ensure that allairflow rates are maintained in accordance withstatements 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 accordancewith procedures described in license application.Check to determine that all personnel using xenon-133 have been trained in these procedures for routineuse of xenon-133.

b. Check to determine that special apparatus foradministration and collection of xenon-133 is beingused, as specified in the license application.

c. Check to determine that special procedures arebeing used to reduce leakage (e.g., use of nosechamps or special enclosures), as specified in thelicense application.

4. Emergency Procedures

Check to determine that all personnel usingxenon-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 RestrictedAreas

Check to determine that air concentrations ofxenon-133 in restricted areas meet the requirementsof §20.103. This may be done by making physicalmeasurements. Alternatively, this may be done byreviewing the use of xenon-133 (Item l.a above),checking the ventilation rate in each area, and per-forming calculations similar to those submitted withthe license application. If the results of the calcula-tions indicate that air concentrations of xenon-133 (asaveraged over one calendar quarter) approach or ex-ceed 1 x 10-1 microcuries per milliliter, then thelicensee should consider and implement methods ofincreasing ventilation rates or of reducing patientload.

6. Methods of Xenon-133 Disposal

a. Dilution through .exhaust systems

Licensees who dispose of xenon-133 by releaseto the atmosphere through an air exhaust system arerequired to perform surveys (i.e., measurements orcalculations) to ensure that they are in compliancewith paragraph 20.1(c) and §20.106 of 10 CFR Part20. Paragraph 20.1 (c) requires that the concentrationsof xenon-133 in effluents to unrestricted areas be aslow as is reasonably achievable by the current state oftechnology, 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 calculationssimilar to those submitted with license application.

If the results indicate that air concentrations ofxenon-133 (as averaged over 1 year) approach or ex-ceed 3 x 10' microcuries per milliliter, then thelicensee should consider and implement methods ofincreasing ventilation rates, reducing patient load, ordecreasing 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 atall stack, Sutton's equation (Refs. 1 and 2) may beused to calculate the concentrations at the nearestunrestricted area. If this approach is used, record thelocation 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 fromcharcoal trapping devices. If the exhaust is vented tothe 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 x10-1 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 exhaustand compared to the allowable limit.

USEFUL CONVERSIONS

1 mCi 103 'uCi

1 ft3 = 2.832X10- 2m 3= 2.832x10 4mI

1 ft 3/min = 1.699X 106 mi/h

= 6.797× 10' ml/40-h week

= 1.484X 10 10 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 HealthPhysics," Pergamon Press, New York, 1969, pp.334-9.

.23-12

APPENDIX BSAMPLE 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 Part20.)

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 STATESNUCLEAR REGULATORY COMMISSION POSTAGE

WASHINGTON, D. C. 20555 U.S. NUCLE

COOFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

120555011962 1 SOUS NRC.Or:FICE OF THE COMMISSIONERSOR .JOSEPH HENDRIECHAIRMANH1149WASHINGTON DC 20

E AND FEES PAID

EAR REGULATORY

'MMISSION

555