ML20205H722

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Case Study Rept on Rupture of I-125 Brachytherapy Source at Univ of Cincinnati Medical Ctr
ML20205H722
Person / Time
Issue date: 08/31/1986
From: Pettijohn S
NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:
Shared Package
ML20205H679 List:
References
TASK-AE, TASK-C601 AEOD-C601, NR-460-S-926-S, SSD-91-71, NUDOCS 8608200138
Download: ML20205H722 (23)
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4 AE00/C601 4

Case Study Report on the Rupture of an Iodine-125 Brachytherapy Source at the University of Cincinnati Medical Center by the Office for Analysis and Evaluation of Operational Data Nonreactor Assessment Staff August 1986 Prepared by:

Samuel L. Pettijohn This report documents the results of a study completed by the Office for Analysis and Evaluation of Operational' Data (AE00) with regard to particular operating events. The findings and recommendations do not necessarily represent the final position or requirements of the responsible program office nor the Nuclear Regulatory Commission.

12 0608200138 ORG PDR PDR

TABLE OF CONTENTS P. age EXECUTIVE

SUMMARY

................................................... 1

1. INTRODUCTION................................................... 5
2. DESCRIPTION OF THE EVENT....................................... 6 4

2.1 General...g............................................... 6 2.2 Chronology of Events...................................... 6 f

3. ANALYSIS OF THE EVENT.......................................... 8 3.1 Seed Rupture.............................................. 8 l 3.2 Contamination and Personnel Uptakes....................... 9 1
4. LICENSEE AND SOURCE MANUFACTURER ACTIONS....................... 11 3

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4.1 Licensee Actions.......................................... 11 1

, 4.2 Source Manufacturer Actions............................... 11

5. FINDINGS....................................................... 12
6. CONCLUSIONS AND RECOMMENDATIONS.....'........................... 13

)

7. REFERENCES..................................................... 14 I
APPENDIX A................................................ 15 i

APPENDIX B................................................ 16 APPENDIX C................................................ 18 i

APPENDIX D................................................ 21 l

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i EXECUTIVE

SUMMARY

The University of Cincinnati Medical Center reported to the Nuclear Regulatory Commission (NRC) Region III by telephone the rupture of an iodine-125 seed (nominal activity of 40 millicuries). The seed, which was one of eight seeds being used by the University of Cincinnati Medical Center for brachytherapy treatment of brain tumors, was ruptured during removal of the seed from Heyer-Schulte coaxial catheters. The seeds, containing iodine-125 adsorbed on anion exchange resin spheres within a .05 mm thick welded titanium capsule, are manufactured by the 3M Company. The 3M Company specification sheet for the seeds indicates that the seeds can be used as removable brachytherapy implants.

Because of the initial high activity of the seeds, the seeds can be used to treat several patients. Furthermore, users of the seeds are motivated to reuse the seeds because of the relatively high cost of the seeds. The use of the seeds as removable implants is in contrast with the use of lower activity (0.1 to 1 millicurie) iodine-125 seeds also manufactured by the 3M Company, which are used as permanent implants (e.g. , prostate cancer treatment).

The seeds are loaded into catheters for use in temporary brachytherapy implants.* Therefore, each reuse of the seeds involves removing them from old catheters and loading them into new ones. It was during this process of removing the seeds from old catheters using scissors, a razor blade, and a needle that one of the seeds was ruptured. The cause of the rupture was

' determined to be a cut by the scissors or one of the other sharp objects used to cut the catheters to free the seeds.

2 Licensee personnel were not immediately aware that one of the seeds had been ruptured.** Consequently, the seeds were loaded into new catheters and implanted in the scheduled patient. As a result, the patient received a thyroid burden and exposure of 557 microcuries and 2087 rads respectively.

The discovery by licensee personnel that a seed (s) had been ruptured followed the discovery of iodine-125 contamination on a source storage / transport bucket for iridium-192 that had been stored in the brachytherapy source room (BSR).

The iodine-125 contamination on the source storage / transport bucket and the iodine-125 seed rupture were discovered on the day after the seeds were removed from an old catheter and loaded into the new catheter and implanted in the patient.

  • Seeds used in permanent implants may also be loaded into catheters; however, there is no requirement to remove the seeds from the catheters since the implants are permanent.
    • 0uring the period in which the seeds were possessed by the hospital the ,

seeds had been removed from old catheters and loaded into new catheters on two separate occasions.

_ ___- - _ _ - _ _ _ _ _ . _ _ _ _ - . - _ _ _ - _ _ _ _ _ _ _ _ - _ - - _ _ _ _ _ _ . _m _________________.___________.-._.---_____m _ _ _ _ _ _ _ _ _

The removal of the seeds from the old catheters and loading of the seeds into the new catheters were done in the BSR, an area not ventilated by a fume hood.

As a result, the BSR, including the exhaust system, was contaminated (1000-11000 dpm/200 cm2). Also, although the BSR exhaust system was on at least for a period of time after the seed rupture, the pressure in the BSR was apparently higher than that in the area outside of the BSR. This higher pressure apparently resulted from a blockage in the BSR exhaust system. This resulted in some iodine-125 being released into an area where a number of hospital personnel received uptakes of iodine-125. In total, at least 60 hospital personnel, including personnel involved in the control and clean-up of the contamination, and a friend of the patient received thyroid uptake doses of

.04 to 209 nanocuries.

Following the seed removal operation, the work area (in the BSR) and the tools used in the removal and loading of the seeds were surveyed with a survey meter normally capable of detecting low levels of iodine-125. However, the BSR had high background radiation which apparently masked the positive indication of contamination. The licensee did not perform wipe surveys normally done to detect low levels of contamination. After the contamination was discovered, licensee personnel took action to control and decontaminate the area.

Because of the seed rupture event, the University of Cincinnati decided to terminate the use of high activity iodine-125 seeds until the safety and health physics aspects of the use of these seeds were studied.*

AE0D undertook a review of this incident to determine if there is a generic problem associated with the reuse of high activity iodine-125 seeds in brachytherapy implant protocols, and to assess any associated health and safety problems.

The incident at the University of Cincinnati is the only incident of its type known to us involving high activity (30-40 millicurie) iodine-125 seeds.

There have been several similar incidents involving the use of low activity (0.1-1 millicurie) iodine-125 seeds. (See NRC Information Notices 80-35 and 80-35, Supplement 1.)

Based on our evaluation of this incident we found that:

1. The risk of an iodine-125 seed rupture is relatively high when the seeds are reused for several patients. The risk of a seed rupture is associated with:

The susceptibility of the seeds to damage from typical tools j used for removing the seeds (razor blade, scissors, etc.); and The discolored or stained condition of the catheters after use in therapy, making viewing of the seeds difficult.

  • As of the date of this report the University of Cincinnati has not resumed the practice of reusing the seeds to treat multiple patients.
2. The consequence of the seed rupture at the University of Cincinnati, involving patient and other personnel uptakes and facility contamination, could have been mitigated by adequate radiation surveys of the work area and the tools used to remove the seeds from the catheter, or by performing a leak test of the seeds. Additionally, personnel uptakes other than the patient and the facility contamination could have likely been prevented if the seed removal operation had been performed under a fume hood.
3. It appears that the consequence (personnel uptakes, and personnel and facility-contamination) of a similar event could also be mitigated by employing radiation safety procedures designed to detect promptly if a seed is ruptured and to prevent personnel uptakes and personnel and facility contamination. Such procedures would include: performing the removal / reloading operation in a fume hood; performing wipe surveys of tools and the area used for the removal and reloading of the seeds; or leak testing the seeds following the removal / reloading operation.

In addition to the specific findings stated above, we believe that attention should be called to one other aspect of the incident:

The University of Cincinnati's licensed program represents a large isotope research and medical use program that typically employs a full-time health physics staff which is generally familiar with the use of a wide variety of radioisotopes. In this event, however, it appears that licensee personnel failed to appreciate or understand the potential for a seed to be ruptured by the seed removal operation or the consequence of such a

  • rupture, in that the protocol describing procedures to be followed for temporary implants did not require (1) that the seed removal operation be conducted in a fume hood; or (2) that a wipes survey leak test
  • be performed to verify the integrity of the seeds before the sources were reused.

Based on our findings, we recommend that:

1. The Office of Inspection and Enforcement (IE) send an Information Notice to the affected licensees describing the event at the University of Cincinnati and describing the action taken by the licensee and the source manufacturer (3M Company) to prevent the recurrence of similar events.
2. The Office of Nuclear Material Safety and Safeguards (NMSS) in conjunction with the appropriate regional office should insure that the 3M Company's license and the license (s) of any other NRC licensees who supply high intensity iodine seeds be amended to require that, in addition to instructions and safety precautions regarding use of the seeds that are i normally communicated to purchasers or other users of the seeds, specific instructions and safety precautions for reusing the seeds be comunicated. i
  • NRC regulations do not require such a leak test.

6 These procedures should include, as a minimum, the recommendation that the removal of the seeds from catheters be done under a fume hood and recommended safety precautions for insuring the prompt detection of a leaking seed, for example, performing comprehensive wipe surveys of tools 3 and the area used for the removal and reloading of the seeds or leak testing the seeds following the removal / reloading operatiun.

3. The Office of Nuclear Material Safety and Safeguards (NMSS) should explore the option of addressing the reuse of the high activity 4 iodine-125 seeds during the license issue, renewal, or amendment process and consider requirfag licensees who will be using the seeds to submit procedures for handling the seeds to NRC for review, i

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1. INTRODUCTION The University of Cincinnati reported to NRC Region III by telephone that an iodine-125 brachytherapy source was found to be leaking. The licensee later submitted a written report giving an account of the circumstances surrounding the source rupture (Ref. 1).

In the month following the event, inspection personnel from the NRC Region III office conducted a special inspection to review the facts surrounding the source rupture.

The results of this inspection are documented in Region III l

Inspection Report No. 30-02764/84-02 (Ref. 2).

The University of Cincinnati's medical isotope program is licensed under 10 CFR Part 33 and Part 35, " Broad Scope Byproduct Material License." A " Broad Scope Byproduct Material License," among other things, authorizes licensees to employ a radiation safety committee to conduct safety evaluations of proposed uses (including human use) of byproduct material (e.g., review facilities and equipment, operating or handling procedures, training and experience of users, etc.)

uses.

and approve such uses in lieu of requesting from NRC approval of proposed The other type of byproduct material license for human use issued by NRC is a " Limited Scope Medical License" authorized under 10 CFR Part 35. This license, among other things, differs from the " Broad Scope Byproduct Material License" in that specific isotopes or groups of isotopes and their authorized uses are listed in the license and any changes in authorized use trust be approved by NRC before the changes are implemented.

In regard to the use or reuse of high intensity iodine-125 seeds, the following observations are made relative to licensing:

Under the " Broad Scope Byproduct Material License," the use of the seeds is authorized through the mechanism of approval of uses of byproduct material by the radiation safety committee.

Under the " Limited Scope Medical License," the use of the seeds is authorized through 10 CFR Part 35.100(f)(8) which authorizes the use of " Iodine-125 as seeds for interstitial treatraent of cancer."

The " Limited Scope Material License" requires the licensee to follow the radiation safety and handling instructions approved by the Nuclear Regulatory Commission or an Agreement State and furnished by the manufacturer in the leaflet or brochure that accompanies the source.

AE00's review and analysis of the incident was undertaken to determine whether there is a generic problem with the reuse (treating several patients with the same set of seeds) of high activity iodine-125 seeds, and to assess any associ-ated health and safety problems. This review is primarily based on information obtained from the licensee's report, the NRC Region III inspection report and a telephone conversation with University of Cincinnati personnel involved with the radiation therapy program. The incident at the University of Cincinnati is the only incident of its type known to us involving high activity (30-40 millicurie) iodine-125 seeds. There have been several similar incidents involving the use of low activity (0.1-1 millicurie) iodine-125 seeds. (See NRC Information Notices 80-35 and 80-35, Supplement 1.)

Section 2 is a description of the source rupture event; Section 3 is an analysis of the event; Section 4 discusses the licensee's and the source manufacturer's actions following the event; Section 5 gives the findings of the study; and Section 6 contains the conclusions and recommendations of the study. Appendix A is a copy of the licensee's protocol for the use of iodine-125 seeds in brachytherapy; Appendix B is the manufacturer's specifica-tion sheet for the iodine-125 seeds; Appendix C is the manufacturer's specification sheet for the Heyer-Schulte coaxial catheters; and Appendix D is the manufacturer's specification sheet for the MiniMonitor 125 radiation survey meter.

2. DESCRIPTION OF THE EVENT 2.1. General The source rupture event at the University of Cincinnati involved the rupture of a high activity (40 millicurie) iodine-125 seed. The seed was one of eight seeds being used as a temporary inplant in the brachytherapy treatment of brain tumors . The seeds were manufactured by the 3M Company. Because the seeds could be used as temporary brachytherapy implants and because of the high activity and relatively high cost of the seeds, the University of Cincinnati was using the same set of seeds to treat several, patients. This reuse of the seeds involved removing the seeds from catheters and loading them into new catheters prior to each insertion. The use of high activity iodine-125 seeds as removable brachytherapy sources was a new procedure at the University of Cincinnati.* Previous uses of iodine-125 seeds involved the use of imi activity iodine-125 seeds (0.1-1 millicurie) as permanent brachytherapy implants.

2.2 Chronology of Events The following excerpt from the NRC Region Ill inspection report gives a chronology of licensee actions leading to the rupture of the iodine-125 seed.

(For further details see Ref. 2.)

(1) On Friday (day 1), the Radiation Safety Office received 400 nil 11 curies of iodine-125 brachytherapy seeds. A total of 10 seeds, 40 millicuries each, were inventoried.

(2) On Monday (day 4), eight of the ten seeds were prepared and implanted.

(3) On Friday (day 8), the seeds were removed from the first patient.

(4) On Monday (day 11), the eight seeds were removed from the original catheters. Five seeds were prepared for treatment of patient 2, however, this treatment was cancelled.

  • A protocol describing procedures to be followed for temporary brain implants received radiation safety committee' approval prior to use of. the seeds (AppendixA). -

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7-(5) On Honday (day 18), the five seeds were removed from the catheter and eight seeds were prepared and implanted into patient 3.

(6) On Tuesday (day 19), a wipe test of a shipping container revealed iodine-125 contamination. Source of contamination was traced to the brachytherapy source storage room [BSR].

(7) On Wednesday (day 20), a wipe test of the patient's head and bandage revealed no contamination.

(8) On Thursday (day 21), a thyroid count on the technician who prepared the seeds revealed a 209 nanocurie uptake.

(9) On Friday (day 22), air flow rates in the brachytherapy source storage room were determined. Urine bioassays of personnel working with the seeds revealed nanocurie amounts of iodine-125.

(10) On Saturday (day 23), the seeds were removed from patient 3.

After explant, a survey of the patient's neck revealed a radiation level of 1.5 mR/hr at two inches from the thyroid.

The patient was discharged.

(11) On Tuesday (day 26), a urine bioassay from the patient revealed 57.6 microcuries of iodine-125. The NRC in Region III was notified.

p (12) On Wednesday (day 27), a thyroid bioassay on patient 3 revealed a burden of 557 microcuries.

(13) On Thursday (day 28), determination of area cont'amination continued. -

(14) On Friday (day 29), the NRC Region III was informed of current conditions and actions taken. Decontamination of the storage room [BSR] continued.

(15) On Monday (day 32), the exhaust system in the storage room

[BSR] was modified to increase flow rates.

(16) On Tuesday (day 33), evaluation of contaminated areas continued.

(17) On Wednesday (day 34), the condition of the patient was determined. The walls in the storage room [BSR] were painted to "fix" the contamination.

(18) On Thursday (day 35), air samples taken from the storage room [BSR] revealed no detectable activity.

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3. ANALYSIS OF THE EVENT 3.1 Seed Rupture A review of the manufacturer's specification sheet for the iodine-125 seeds shows that the seeds consist of a welded titanium capsule containing iodine-125 adsorbed on anion exchange resin spheres (Appendix B). The titanium capsule  ;

wall thickness is .05 mm. The capsule is a cylinder .8 mm in diameter and 4.5 mm long. The catheters'used at the University of Cincinnati were Heyer-Schulte coaxial after-loading catheters made of a silicone elastomer.

They consist of an inner and an outer catheter, 16.5 cm long and 15 cm long, respectively (Appendix C). The catheter manufacturer specifies that the catheters are recommended for " single use only"; therefore, reuse of the iodine-125 seeds contained in the catheters requires removing the seeds from the old catheter and loading them into a new catheter.

The technique used for removing the seeds from the catheters at the University of Cincinnati consisted of first cutting the ends off of the catheters using scissors and then using a razor blade to shear the plastic tubing longi-tudinally in such a manner as to expose the bare seed within the catheter enough so that forceps could grasp the seed. This same technique was reportedly used for removing the seeds on both day 11 and day 18. The protocol i describing procedures to be followed for using the high activity iodine-125 seeds for temporary implants did not address how to remove the seeds from the catheters. The technologist involved in the seed removal feels that the seed was likely ruptured by the scissors when the ends of the catheters were cut off.

2 Following the discovery of iodine-125 contamination in the BSR and after the sources were removed from the patient, all sources were returned to the 3M Company for analysis. An excerpt from the 3M Company report of the analysis states: (Ref. 3)

In conclusion, of the ten high-activity I-125 seeds returned to 3M for inspection following discovery of radioactive contamination at your institution, only one seed (seed #2) released I-125. In our estimation this release was caused by structural damage to the titanium shell of the seed in the form of a transverse cut near the weld end. The cut may have been caused by a scissors or wire cutter, etc. , used to free seeds from the catheters prior to loading them into new catheters. i This result is consistent with the technologist's view of the cause of the seed rupture.

The technologist involved in the seed removal feels that this cut had likely ,

occurred during~ removal of the seeds on day 11. The seeds removed at that time l were coatained in catheters that were stained from having been implanted in a l tumor, thus making it difficult to see the seeds in the catheter. In addition, the technologist indicated that the inner catheter and outer catheter were stuck together and could not be separated, further hindering visibility of the seeds. By contrast, the seeds that were removed from the catheters on day 18 had not been used (i.e., the therapy use had been cancelled); therefore, the catheters were clear and allowed greater visibility of the seeds.

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t a 3.2 Contamination and Personnel Uptakes The removal of the seeds on both day 11 and day 18 was done in the brachy-1 therapy source room in an open area that was not ventilated by a fume hood.

j Also, the BSR apparently was under a slight positive pressure at the time because of a blockage in the room's exhaust system (a damper was partially closed) that reduced the exhaust flow rate to less than the exhaust flow rate for the area outside of the BSR.*

Licensee personnel stated that both times the seeds were removed, radiation

  1. surveys of the work area and the tools used in removing the seeds were made and that these surveys revealed no contamination. The surveys were made with a Nuclear Associate MiniMonitor 125 which, according to the manufacturer's

! specification sheet, has a minimum range of 0-500 counts per minute (cpm)

, (Appendix D). The Reaion III inspection report noted that the background j

' radiation level in the CSR was normally high because of the proximity of other brachytherapy sources. This made it difficult to detect contamination using a

.; survey meter. Wipe surveys, which involve wiping suspected contaminated areas i with cotton swabs or similar material and later counting the wipes, were not

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i done. Good health physics practices and NRC regulatory requirements indicate that, under the circumstances, wipe surveys should have been performed to look i

for contamination.** In addition, good health physics practices indicate that, since removal of the seeds from catheters involved non-routine handling of the

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seeds which increased the risk that seeds could be damaged, the seeds should have been leak-tested following removal of the seeds from the catheters. The

protocol describing procedures to be followed for using the high activity iodine-125 seeds for temporary implants did not address wipe surveys or leak l testing of the seeds.

On day 19, the day after the sources were implanted in a patient, the licensee discovered iodine-125 contamination on a source storage / transport bucket for iridium-192 that had been stored in the BSR. The iodine-125 contamination which was discovered during routine wipe surveys of the bucket (being prepared for shipment) averaged approximately 625 dpm/200 cm2 The contamination was traced to the BSR. The BSR was sealed off and decontamination was begun. Wipe testing of the brachytherapy source room revealed contamination levels of

, 1000-11000 dpm/200 cm2 ,

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The day following the discovery of iodine-125 contamination in the BSR, licensee personnel wipe tested the patient's lead hat and bandage to check for contamination. No contamination was found. Later, after. it was determined 4

  • Following the discovery of contamination in the BSR, it was closed off using plastic over the door. It was noted that the plastic was ballooned l

outward, indicating a positive differential pressure between the BSR and j the area outside of the BSR. .

    • The' licensee was cited by NRC/ Region III for being in violation of 10 CFR 20.201(b), which requires licensees to make surveys as necessary and reasonable under the circumstances to evaluate the radiation hazards.

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that the source of the iodine-125 contamination was the implanted seeds, a medical decision was made to leave the sources implanted for the prescribed period of the therapy (Ref. 4).*

The implanted seeds were removed from the patient on day 23. The catheters containing the seeds were placed in a lead-shielded contaipar and taken to the radiation safety laboratory and placed in a fume hood. The catheters containing the seeds were later sent to the 3M Company for evaluation. A survey of the patient's roem with a survey meter revealed no contamination. However, a survey of the patient revealed a radiation level of 1.5 millirem per hour 2 inches from the thyroid gland. The patient was released from the hospital on day 25. On day 27, the patient returned to the hospital for a bioassay and the results indicated a thyroid burden and exposure of 557 microcuries and 2087 rads, respectively.

The positive differential pressure between the BSR and the area outside it existed for several days following the discovery of iodine-125 contamination in the room. The positive differential pressure contributed to the airborne migration of the iodine-125 into adjacent areas. This resulted in numerous personnel who frequented these areas receiving uptakes of iodine-125. Other personnel involved in the control and cleanup of the contamination also received iodine-125 uptakes. Bioassay results for these personnel indicated that:

The technician who prepared the iodine-125 seeds had a thyroid uptake of 209 nanocuries; and At least sixty hospital personnel and a friend of the patient had thyroid uptakes that ranged from .04 to 209 nanocuries.

The maximum permissible thyroid burden (MPBB) for iodine-125 is 500 nanocuries.

Although the contamination of the BSR was extensive, wipe surveys and air samples revealed that the contamination was essentially limited to the BSR.

Wipe tests taken in the brachytherapy source room on day 29 showed contamina-tion levels that ranged from 160-3900 dpm/200 cm2 for the wall and floor to 1900 dpm/200 cm2 on the lowered-ceiling tiles. A maximum total of 25 micro-curies of iodine-125 was estimated to be in the paint on the walls. Air samples taken in the BSR on day 32 showed air concentrations of 125 dpm/20 ft2 (less than the maximum permissible concentrations for restricted areas).

Air samples taken outside of the BSR showed negligible iodine-125 concentra-tions. However, some contamination (low level) was found on the surface area of the BSR exhaust vent at the point of release.

The University of Cincinnati successfully decontaminated the BSR or fixed the contamination by repainting the walls.

  • Because a medical evaluation and decision was made to leave the implanted sources in place, the iodine-125 uptake by the patient was not deemed by NRC to be a medical misadministration as defined in 10 CFR 35.41.

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4. LICENSEE AND SOURCE MANUFACTURER ACTIONS 4.1 Licensee Actions As a result of the source rupture, the University of Cincinnati suspended the use of high intensity iodine-125 seeds pending the investigation of the event (Ref. 5).* The University of Cincinnati, in their response to the NRC Notice of Violation,** expressed concern that there was a likelihood of other occur-rences of source ruptures involving the reuse of high intensity iodine-125 seeds.

An excerpt from the University of Cincinnati's response is as follows:

The sealed source was opened by a radiation safety technologist under conditions of poor visibility. This accident could have happened at any installation in the country where the seeds would have been placed in plastic tubing which becomes discolored from use and an attempt made to retrieve the seeds and reutilize them because of their cost.

4.2 Source Manufacturer Actions In a letter to NRC dated February 11, 1985, regarding the 3M Company's " peer review" of the AEOD preliminary case study report of the event, the Company stated that " subsequent to the Cincinnati incident, 3M upgraded its internal procedures aimed at providing additional control for institutions /uses it:volving high activity seeds."

, The following description of the upgraded procedures was presented:

1. 3M Customer Service directs all phone inquires about the use of I-125 Seeds Model 6702 for brain implants to someone in Technical Service.
2. This Technical Service person summarizes 3M's REQUIREMENTS of an institution prior to selling the seeds for such use, which include submission to 3M of 1) a Brain Implant Protocol, 2) an Institutional Review Board (or equivalent) approval of that protocol, and 3) a copy of the Patient Informed Consent form.

In the same phone conversation, risks and hazards associated with the handling of the 30-40 mci seeds are summarized to include the consequences of cutting a seed while removing it from the afterloading catheters. (The Cincinnati incident is alluded to but the hospital is not identified.)

  • As of the date of this report the University of Cincinnati has not resumed the practice of reusing the seeds to treat multiple patients.
    • The University of Cincinnati was in noncompliance with the License Condition 15, which states that sealed sources shall not be opened, and 10 CFR 20.210, failure to make adequate radiation surveys.
3. A follow-up Brain Implant Protocol letter is mailed to the customer.

Prior to the Cincinnati incident, a phone call was not always followed with a letter since it was believed that adequate verbal instructions were given to a knowledgeable customer.... Following'the Cincinnati incident, a follow-up letter was always sent.... We believe that requiring a radiation safety section in the implant protocol provided adequate assurance that the seeds would not be mishandled if reused.

The letters also directed the customer to knowledgeable people

[in 3M] who could advise about the proper handling of seeds during reuse.

5. FINDINGS
1. The risk of an iodine-125 seed rupture is relatively high when the seeds are reused for several patients. The risk of a seed rupture is associated with:

The susceptibility of the seeds to damage from typical tools used for removing the seeds (razor blade, scissors, etc.); and The discolored or stained condition of the catheters after use in therapy, making viewing of the seeds difficult.

2. The consequence of the seed rupture at the University of Cincinnati, involving patient and other personnel uptakes and the facility contamina-7 tion, could have been mitigated by adequate radiation surveys of the work area and the tools used to remove the seeds from the catheter, or by performing a leak test of the' seeds. Additionally, personnel uptakes other than the patient and the facility contamination could have likely been prevented if the seed removal operation had been performed under a fume hood.
3. It appears that the consequence (personnel uptakes, and personnel and facility contamination) of a similar event could also be mitigated by employing radiation safety procedures designed to detect promptly if a seed is rupture ( and to prevent personnel uptakes and personnel and facility contamination. Such procedures would include: performing the removal / reloading operation in a fume hood; performing wipe surveys of tools and the area used for the removal and reloading of the seeds; or leak testing the seeds following the removal / reloading operation.

In addition to the specific findings stated above, we believe that attention should be called to one other aspect of the incident:

The University of Cincinnati's licensed program represents a large isotope research and medical use program that typically employs a full-time health physics staff which is generally l familiar with the use of a wide variety of radioisotopes. In this event, however, it appears that licensee personnel failed to appreciate or understand _the potential for a seed to be

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ruptured by the seed removal operation or the consequence of

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such a rupture, in that the protocol describing procedures to l be followed for temporary implants did not require (1) that the seed removal operation be conducted in a fume hood; or (2) that a wipes survey leak test be performed to verify the integrity of the seeds before the sources were reused.

6. CONCLUSIONS AND RECOMMENDATIONS Based on our findings, we recommend that:
1. The Office of Inspection and Enforcement (IE) send an Information Notice to the affected licensees describing the event at the University of Cincinnati and describing the action taken by the licensee and the source manufacturer (3M Company) to prevent the recurrence of similar events.
2. The Office of Nuclear Material Safety and Safeguards (NMSS) in conjunction with the appropriate regional office should insure that the 3M Company's license and the license (s) of any other NRC licensees who supply high intensity iodine seeds be amended to require that, in addition to instructions and safety precautions regarding use of the seeds that are normally communicated to purchasers or other users of the seeds, specific instructions and safety precautions for reusing the seeds be communicated.

These procedures should include, as a minimum, the recommendation that the removal of the seeds from catheters be done under a fume hood and recommended safety precautions for insuring the prompt detection of a leaking seed, for example, performing comprehensive wipe surveys of tools and the area used for the removal and reloading of the seeds or leak testing the seeds following the removal / reloading operation.

3. The Office of Nuclear Material Safety and Safeguards (NMSS) should explore the option of addressing the reuse of the high activity iodine-125 seeds during the license issue, renewal, or amendment process and consider requiring licensees who will be using the seeds to submit procedures for handling the seeds to NRC for review.

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7. REFERENCES (1) Letter from Eugene L. Saenger, M.D., to NRC.

(2) Region III Inspection Report Number 30-02764/84-02 (DRSS).

(3) Letter from David Kubiatowicz, Medical Products Division, 3M Company to Peter Ho, M.D. , Department of Radiation Therapy, University of Cincinnati Hospital General.

(4) Letter from Eugene L. Saenger, M.D., Chairman, Radiation Safety Committee, University of Cincinnati Medical Center, to William Axelson, NRC (Region III).

1 (5) Memorandum from Eugene L. Saenger, M.D., University of Cincinnati Medical Center to Bernard S. Arin, M.D. and Peter Y. C. Ho, M.D.,

University of Cincinnati Medical Center.

(6) Letter from Robert G. Wissink, Manager, Health Physics Services, 3M Company tar Darrell Wiedeman, Chief, Materials Radiation Protection q Section, NRC (Region III).

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APPENDIX A P otocol for the use of 125 1 sealed sources for implant into pat ient 's tumor:

1. Upon receiving 125 1 shipment i

A. A wipe test is first made inside the- source container bottle by Radiation Saf ety to detect possib le leakage of the sealed source.

B.

Calibration of each shipment of sealed sources is done by Ra dia tiom Oncology with a dose calibrator using an NBS standard source (avai lable late 1983).

2. Preparation for imp lants A. The 125 1 seeds are loaded into shiel ded cartridges or af terloading devices by Radiation Oncology technologist /staf f/ residents with special

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tools designed for handling the seeds standing beh ind a lead shiel d or wearing a lead apron.

B.

Af terloading, the instrumnnts used for handling the 125 1 seeds wil I be bhecked with'a thin window counter to check for leakage contamination due to possible mechanical damage to the seeds.

C.

The shielded cartridges or af terloading devices are gas sterilized for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or steam sterIIIzed for 10 minutes.

3.

During implant in patients and immediately post imp lant A.

The instruments used in the implant should be conitored with a thin window counter af ter the imp lant to check for leckage contamination due to possib le mechanical damage to the seeds.

B.

The suctfor checked ionloose apparatus, 125 tubing and traps, including the Foley bag ere 1 seeds and removed appropriately for disposal by Radiation Oncology or Radiation Safety.

4 Post implant monitoring per Radiation Saf ety regarding exposure to personnel

5. If leakage is discovered A.

Upon receiving shipment - container is to.be ~ sealed and disposed appropriately by Radiation Safety.

B.

During handling of seeds - all personnel or patients involved are to have their urine checked and undergo thyroid counting to ronitor expostre.

6. All unused 125 1 seeds are to be returned to Radiation Saf ety for disposal except for reusable high activity 125 1 se ed s (40 mC I), which are to be stored in Radiation Oncology's shielded safe.

activity is below 10 mci each. These will be returned when the 7.

All operators and technologists handling 125 1 seeds will wear finger badges.

, -w

  • APPENDIX 8

-25 Seeds No.6702 Description Warnings 3.125 Seeds 6702 consist of a welded titanium capsule containing todine.125 avsarbed on anion enchange resin spheres. The 1 125 Seed titanium capsule has excettent corrosion resistance, but it is attacked by concentrated hydrocnioric acid.

I.125 Seeds have been designed not to be used in a concentratec g, hcl environment.

......acn.ae. 0 05 mm em e sea . Precautions Preparation for Use/ Sterilization i N__ .

~l

~

/s.

8 125 Seeds are radioactsve and appropriate precautions must be taken when handling these sources. Alf steps of the smolantatiors o.e sam .d$.

'+ -hb. -" h~ .) y procedure should be planned in advancie to minimize radiation exposure to persorinet. consistent with 33ublished exposure limits.

j l Personnel morutoring is required for mchvaduals working with I.12 4.s mm Seeds. A film badge or TLD dosimeter worn on the body and, for

/ handling, a ring badge wdl provide adequate detection.

Physical Characteristics

' 3 125 Seeds are provided in a glass vial which should be lodine 125 has a half-life of 60.2 days and decays by electron

_papture witn tne emission of ct.saracteristic photons and Auger rnaintained in a lead vial container for storage. When transporting seeds within the hospital premises, an appropriate carner with efectrons. The electrons are absorbed Dy the titanium wall of adequate shielding should be used.

the 1 125 Seed. The, principal photon emissions are 27.4 and . All manip'usations involving 1.125 Seeds should be carried out 35.5 kev s-rays and a 35.5 key gamma.

To correct for the physical decay of sodine-125 the decay factors behind shielding of'such size and thickness as will adeouately shield theoperator. DIRECT CONTACT WITH THE SOURCES at selected days alter the assay date are shown en the table below.

SHOULD BE AVOIDED.In addition.I.125 Seeds should be

o. car ca.<t ned.a..i25.we vie so.2 oars handled only with Iorceps. with as muca distance as oractical o.c., o.c.y between sources and tne operator.l.12S SEEDS SHOULD NOT o.rs F.crer Days F.ctor
o. BE PICKED UP WITH THE HANDS.

. ..teco 26 . . . . .. .. . . 0.661 1-125 Seeds are NOT sterile when shipped and as such must be 6$......".. N 33g

$0.933 42 N l'.'."['.[

".l.~ 0 617 sterilized with steam (autoclave) or ethytene oxide (EO) before Implantation. Regardless of the methoca selected. I.125 Seeds

8. . 0.912 44 to . ... .

. 0 att 46 .

. . . . . . . . . . . . . 0 6o3

. . . . . . ... . 0 189 should be placed in an adequately shiesded Container prior to 12 . . .. . 0.871 48 . . . 0.575 placementin the sterilization charnber. Manipulation of the seco

. ... .0 . . . ... . . ... prior to or following sterikzation should be carried cut Denind

' '" shielding of such size and thickness aswilladequately sheeld the te . .. l 0 an3 54 . . . . l . ' ~. "." ' O.5 3 7 operator. In addition. I 125 Seeds shoutd be handled only with 20 . . . . . . . 0.794 56 . . ... . .. . . 0.525 22 . . .. c.776 58 forceps, with as much distance as pracucal between sources and

. .... ... . 0.513 24 .. . .. . 0.759 60 . . . .. . 0 501 the operator. Autoctaves should be equipped with traps or other

.s. . 0 741 62 . . . . . . . . . . . . . 0. 4 9 0 means to prevent seed loss through the drain hole.

2e . .. . . . . . c. 7 2 4 64 . . . . . . . . . . . . . c. 4 7 s so . ... . o 7cs 66 . I.125 Seeds have been designed to wi:ttstand normat actJctave

. . . . . . . o. 4 6 a temperature and pressure variations from 121' C at t5 osi to 32 . .. . .. . o 692 ss . .. ... .. . c.4 57 s4 .. .... . .c676 To . . .. ..... . ...o.447 138' C at 35 psi.1 125 SEEDS ARE NOT INTENDED TO BE Radiation Protection STERttl2ED USING DRY HEAT AND SHOULD NOT BE SUBJECTED TO TEMPERATURES AND PRESSURES IN The hatt value thickness of lead for Icdine.125 is 0.025 mm. Thus, a EXCESS OF THESE LIMITS (128* C and 35 psi).

0.25 mm lead sheet will provide > 99% reduction in exposure. 8 125 Seeds should be autoctaved in bulk or individuallyin Actions appropriate containers of autoclave. compatible matersals. Thes.

materiais include stainless steet. glass. nyton and serion. l.125 I-125 Seeds emit 27.4 and 3a 5 kev x. rays and a 35.5 kev Seeds may also be autoctaved in selected accessories to gamma. The cl.rucat efficacy of the sources derives solely from commencally availableimplant tools. Among these accessories the iiteraction of these sonizang radsations with the tissue being are the staankss steelcartodge of the Mck appiscator and gun, treated. and riylon and teflon tubeng used as seed holdats with Henschk e and Scott applicators. When in doubt acout the enemical riature Oose distribution around eacn individuat seed is not isotropic. This of these de'ed holders, either sterilire tne matersals witn etnylene enisotropy should be included in dose distribution calculations.

~ Oxide or autoclave a sample of the matersats contaaning dummy Titanium encapsulation assures good tissue compatibility and seeds before attempting to load with radioactive seeds. DO NOT resultsin a total self-acsorption of approximately 16%. AUTOCLAVE 8125 SEEDS IN PLASTIC TUBING OR OTHER PLASTIC CONTAINERS.

Indications , ,, Although I.125 Seeds have a high structuralintegrity. it as possit; 3 125 Seeds are indicated for interstitialtreatment of tumors which through rough handlang. high temperatures or crustung. that a have Ine f onowing ch3racteristics: unresectable, localized. and seed coutd leak or be rupturedclf sucn a rare occurrence does modera te ra dsosensitivity. happen, the area should be closed off, tne seeds packaged into a 1 125 Seeds may be used for selected radiation applications as sealed container and the area decontammated. Decontaminatson removaole emplants. can be confirmed by taking wipe samples of theimmediate area Personnel movement should be controlled to avoed seread of an s 1 125 Seed s are indicated to treat residual tumors following radioactive contaminatac,n. Whenever a socrce is damaged,

completion of a course of externat radiation therapy.in additson, personnel working in the area should undergo a thyroed scan to t

recurrent tumors may be emplanted with I.125 Seeds. assure that tney have not been contars. mated Dy constet. engestet.

or inhalation of lodene.125. .

Contraindication 5 As with other brachytherapy sources. treatment of tumorsin s

,9!neraffy coor condition PQ ti'Ceutadt d not recommended with

i l

. h8edical Products Division /3M TCAAP c-b New Brighton, Minnesota 55112 s;

Certification 'mS4963 70 4.9 lodi e.125 Sealed Sources For Medical Uses' 1 Sep.1983 Consignee: UNIV CINCINNATI MED. CTR RA0TOIS0 TOPE 1AB Address: 234 GOODMAN ST CINCINNATI. OH 45267 V

The following radioactive sources are certified by Minnesota Mining and Manufacturing Company (3M)tc have been subjected to the tests described below and to have been given the results listed.

Modet Number gy Lot Nurneer , yg,g)g Ovantity c 39 .

- c c . .-

l Activity Range (mci)*

38.0 4 3 Total Activity (mCl)*

390.O I Assay Date g  !

A!! seeds have passed a leak test showing <0.005pCI of removable 12s ~

is to be implied.

iodine activity. No other certification

  • By ' mci" we mean " apparent activity in millicuries", which is descriptive of output activity only and not the total t;uantity of I 125 contained within the titanium capsule of the Seed.

For accounting purposes, the cuantity of I-125 contained in Model6702 or Model 6711 Seeds is about 1.2 or l 1.6 respectively multiplied by tne stated apparent activity in millicuries.

Read theofreverse definition sideactivity

" apparent of this in form for information about Seed construction method of calibration and millicuries".

i- . ~

) ,[dFG _. . 1 ,, _ 9 Aunutt 1984 s

Quality Control Date N& ~

M~

V.

~

1 1

1

\

l

+

1 The following procedure Is furnished by Phillio H. Gutin, Special order devices are M.D.," for informational supptled either sterlie or purposes; nonsterite es Indicated on the product label. Nonstrelle $PECiflCAflDNS (All Dimensions are Nominal) the Coastel Afterloading products, if Intended for Implantation of an aseptlC Catalo9 $wture Catheter can be used for applicotton, cust be c leaned Number Descriptlen yle Collar Catheter Leegth; implantion of radioactive Oga*eter Inner sources into brain tumors, and steriffred prior to uses O tter if your product is nonsterile, Gol0035 01 Comatal Afterloading The outer catheter is the cleaning and sterillsation .g3 Cathet,c Clear 2 cm 16.5 cm Il ce generally placed to a t umor 03 medlopeoue 2 cm target through a burr hole or procedures given below have medlooecue SL.S cm  !) cm 04 I cm 15.$ cm twist drill hole using a been found effective and are Redloceque 2 cm 27 cm stylet guided by computed. provided as a guide. 23.5 cm 27 cm

$pecial Order tomngraphy directed

$7tRittfAfl0N Devices are Manufactured 8 Distributed by:

stereotear. The Catheter AmtRICAN Htyre.$CHutit gasses throu0h the etlicone base before entering the This product I s recommenderf Olvision of brain. for single u98 only. It is american Hospital Supoly Corporation recommended that each 600 Pine Avenue Coleta C A $}lly When the catheter is at the institution estabilsh the Telephone (805) 967 34$1 target, the silicone base is efficeCy of Its sterillration pushed down to the skin or to procedure by a method which the skull. It can then be includes the sterlitration of en Intentionally tutured in position, or, in contaminated g product.

the case of the skull, it can >4

>3 glued to the bone with 03 biological adhesive. Then, Do not sterillre in the the outer catheter is glued to pocheoino system supplied. ,

the base with biological the following cleaning and echesive. The stylet is ,

steelllration technloues have removed and coptoced with the ,-~'-

been found effective and are

~

BLaer catheter contelning the provided as a guide * ,

rtdloactive sources. The e inner catheter is secured to

  • Remove the Heyer.$chulte the outer Catheter with a droD Comale) Afterloading Catheter 6f biolo4ICal adhesive. from its packe0e In a cle8m How $UPPtlED envfronment using glowed hands. Lipt, fingerprints, Eich catheter is provided tale and nther surface Individually wrapoed in a contaminant s Can cause forel0m body reattlons. Utmost NON$ffeltf Condition, and tansists of en esternal caution thould be taken to ectheter with tuturing flenge evold contaminents.

89d two telescoping internal Une en alcohol (ethyl or catheters.. All catheters must IsoproDyl) swab to remove olly Manufactured and Distributed byl b) Cleened and steelliged per th) Instructions below. surfect contaminants.

AMERICAN HEYtt.$CHULTE )>

Pihlllip H. Cutln, M.D. Hand wash solled sllicone Olvision of '

90 American Hospital Supply Corporation 93 University of Californle devlees for e mastmum of Il 600 Pine Avenue Hospitals minutes in a solution of mild Colete CA 11117 $2 i 505 Pernassus surancel soap or e one percent tg antonic detergent. If it Is telephone (805) 967 345) w*

Department of Neurosurgery OteM473 necessary to use a brush, only >$

$ n Francisco, 94143 II k

Functional fellure of the Cathette system due to Pe0 DUCT INf0eMAfl0N DISCLOSURE separation of its Component International Customers - Coughtln, Christopher T., Even part s can result in Serlous AmerlCan Heyer-Schulte has Cataloa Products S. 00uple, John W.

welter L. faton Jr.,Strohbehn, comolications. Catheters may eserclSed reasonable care in migrate into other areas the cholce of materials and For product Information or to 8. Stuart causing serious harm to the manufacture of this product, order directly, contact your Trembly, and T.I. wong, patient. American Heyer-Schulte local American Heyer-Schulte "Interstlttel Hyperthermtp in escludes all warrantlet d stributor or the American V. Combinetton with Infection i s a c ommon and whether empressed or leplied e

Mueller international Customer Srechytherapy," medlolecy. 148 serious complicat ion of by operation of law or Service Department at 1500 (July till), 285-2I8 a

catheter system and is most other=lse, including, but not Waukegan Road, McGow Park IL Cheryulu, K.K.N.:

frecuently caused by skin limited to, any implied 60005 USA. Telephone (312) "A new contaminents. Septicemte, =arrantles of eerchantebility 47).I500, Telen (Twx) 110 aftertoeding techoloue for whlch occurs mnet frequently pr Fitness.

American Hever- 230-195. interstitial Irradiation using In debilitated Infants, can schulte shall not be liable radloactive microspheres." Am for any in Canada, contact AHS/ Medical J. _ toent eenol medium Ther Nuct result from inrections _I nc l dent a l o r_

Specialties, Division of McGaw Med. 102: (1964), til.

env=here in the body and mov consequential loss. damage or sevelop with few or no empense, directly or Supply Ltd., 2390 Arnentle Cohen, J.C. and D.M.

symptoms. It may occur as e indirectly arlsing from the . Road, Mississauge, Ontario, "A How Approach to the Sklarc f f, result use of thls product. Canade L$N 3Pl.

in the of a wound or an Infection.

Telephone event Infectlon, Heyer-Schulte neither American assumes (416) 821-9093. Surgical-Radiologic Manageeent removal of the catheter system nor authorizes any other Of Breast Cancer with is Indicated in addition to person to assume for it, any internattonal Customers - Interstittel Bridlum, Journal the appropriate chemotherapy. other or additional liability 5pecial Products of ske Albert tinstein Medscal I or responsibilft, sn

~

tenter, vol. 5, No. 1, RETUANED C0005 POLICT connection with this device. por Information on special (December 1936). p, y3 order devices, please contect Fletcher, C.H.,

U.S. Customers PeCDUCt ORDER INrceMATION the Customer Service ano M. I Department at American stovall: "A study of Autnorlantion must be received V.S. Customers - Cetalot Heyer-Schulte, 600 Pine esplicit distribution of from American Heyer-schulte, Products Avenue, Golete CA 93117 USA. radiation in Interstitial Sivision of American Hospital Telephone (805) 967-3451, ImolantatIon." Asdlelocy, FI:

Supply Corporatlon, prlor to To order directly in the teles (twx) $l0 334-II65. (1962), 766-782.

U.S.A., please contact the return of merchandtse. Cray, C.R., I, Sheldon, M.D.

Marchandise returned must have American V. Mueller, eactustve Cautlen: Federal low Freedmen, and A.R. Kagen*

all manufacturer's seals United States distelbutor for all American Meyer-Schulte restricts this device to selg Intact and be received withtn o, or on the oroer or a ~

"r lbros erc ome: A comolicat ion 60 days of date of involte to products =lth distribution physicien. of Interstittel redletion ce elselple for credlt or centers in Irvine and Hayward therapy for a beten rtplacement. Returned pt9Lf0CRAPHY heemangloma occuring after 18 CAs Orlando FLI Norerats cal Vests." Dr. J. of_eedlelogy, groducts may be subject to McCow Park its Sedford mas Awwerd, H.K., 175 (1974), 40 61.

rsstocking charges. nomulus Mis Minnesoolls MNs J.M.V. eurter$,

Maryland Heights MOs Edison and H.R. Marcuset "The Cuttn, Phillip M. and any M.

Jnternettonal Customael NJs Columbus ohs Archardson and woodland Tx, influence of tumor dose Dormandy Jr., "A Coenfal specification on the earl, Catheter System for Autherlantion for return of clinical resul,ts of Interstitial radium Longue Afterleedine Radle8ct8'*

awechendise should be obtelned U.S. Custome4.s Products - Stfetal Sources for Interstltlel from your respective dealer. implants" asg alal gr 1801 Cther coaditions noted above (1974), 1777Ts3. teradistJoa of grain fumors,"

clso apply. For Information on special di Neurosura, 56 (May 1987),

order devices, please contatt Coryulu, R.E.N.I "An 734-735.

the Customer Service afterloading method for Cuttn, Phillip H. et al, Department of Amerleen Interstitfal implantation of Heyer-Schulte, 600 Pine radioactive seed." " Permanent and Removable Avenue, coleta CA 13187. penminerve Med. 13' (1978), Implants for the erschytherapy Inti-free telephone (a00) j$9 365 of aceln rumors," eediat lan.

235-573s. Oncologo. 916 9 o2 Y = r hr 8 ' rl.

7:30 (october 1984),

1371-1388.

e D B 73P

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. w., ._-

'N " $ '

e f e,

Sh snless, t o 3 il f V 51CCA boHon

, c_g umm - - - - - - - - -

6 dj-

\sman KC0

.\ SMae <-

EkT EU35 To Tt P e

c, e nem -

4; 4]410 heob PI6 t .6% 7VLom WM9 Imm 1 m

0AA WJ<!11692LY '

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, . _ _ - - -m,. .

fPPENDIX-0 MiniMonitor 125 - - ' ' ~

Contamination Monitor C. -

Measure _s low-level *1 surface

/ .S N ' ..

~/ . . ,

,g "-

contamination quickly and accurately ,1 h ' ' #,

g ('-

, k .-_ -

.u o High sensitivity (lower detection limit-0.002 Ci). ( ,

y e Three ranges (0-500, SK and 50K cpm). # U'q.,

A e Large. area, screened detector permits contact I surface measurements.

j; f

.. /

For the first time, a compact, sensitive monitor is avail.

able for the detection of Cl surface contamination

  • O h y.~

levels as low as 0.002 aCi.

A large. area. thin. window GM detector, recessed in a .

conical housing on the back of the instrument, permits Detector: Halogen. quenched G141 pancake tube,1.2* diam.

direct-contact measurements of surfaces. The maximum Readout: 2%~ analor meter, marked 0 to S00.

amount of removable contamination allowed' (0.005 Ranges: 0 500,0 5,000,0 50,000 cpm.

  • Cin is well within the detector limits of the unit. All Accuracy::10% of full scale, su-faces as well as hands. clothing shoes, etc., may be Controls: off, Battery Test, x100, x10, x1 ranges-all on routinely monitored by using this hand. held instrument. one switch.

Lightweight (22 ounces) and portable, the monitor op. Time Constants: 10 sees (x1): 2 secs (x10); 03 sees (x100).

erstes on 4 alkaline "A A" cells. All controls are con. Ba tte ries : Fou r "A A" alkaline cells (500. hour life).

veniently located on the instrument's face. An LED in. operating Tem peratu re:-20'C to + 55'C (-4*F to '130* F).

dicator flashes with each incident radiation pulse. The Temperature Dependence: 215% over noted temperature LED also indicates that the unit is "on." range.

MiniMonitor 125 may be used as a convenient, general. Construction: All solid state electronics.High-impact piastic response survey meter for radiation detection in the **5' laboratory. The 3. range selector swsteh permits rapid , ; g  ; pj,,g .

g g ,

changing of survey ranges, Radiation levels are read g,

on a large 2% meter. The monitor includes a plastic g;te C. high x 3 *+~ wide x 2" thick. Weight: 22 ounces.

contamination shield for protecting the detector hous.

ing and a license. free radioactive source for checking 03 372 MiniMonitor 125 Corteamination Monitor s325.00 the instrument's overall operation. - Per NP.C or Agreement State regulations. -

4 .

. , . . _ .

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