ML20206L840
| ML20206L840 | |
| Person / Time | |
|---|---|
| Issue date: | 08/12/1986 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Bush J MINNESOTA MINING & MANUFACTURING CO. (3M CO.) |
| References | |
| NUDOCS 8608200317 | |
| Download: ML20206L840 (2) | |
Text
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UNITED STATES y
g NUCLEAR REGULATORY COMMISSION r,,
WASHINGTON, O C. PMM AUG12 19g5 e....
Ms. Jacquelyn D. Bush Manager, Regulatory Affairs Medical-Surgical Division /3M 3M Center, 270-4A-05 St. Paul, MN 55144
Dear Ms. Bush:
SUBJECT:
AE00 CASE STIJOY REPORT ON THE RUP10RE OF AN 10 DINE-125 BRACHYTHERAPY SOURCE AT THE UNIVERSITY OF CINCINNATI MEDICAL CENTER Enclosed for your information is the AE00 Case Study Report on the Rupture of an Iodine-125 Brachytherapy Source at the University of Cincinnati Medical Center.
This report was issued December 27, 1985 for peer review and has been revised based on the comments received during the peer review.
Our study, together with peer review comments, have led us to make the following recommendations:
1.
The Office of Inspection and Enforcement (IE) should 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.
8608200317 860812 PDR ORG NEXO PDR
Ms. Jacqu lyn D. Bush AUG 121986 If you should have any questions regarding the report, please contact Samuel L. Pettijohn of this office at (301) 492-4496.
Sincerely, wsasnesny c J. Hen.m,;r.
C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
Enclosure:
As Stated Distribution:
'DCS AEOD CF AE0D SF AE0D Library NAS CF C. J. Heltemes F. J. Hebdon K. Black S. Pettijchn D. Humenansky 0FC :NA
- C/N
- DD/AE0[
- D/AEOD
_ _ ___ : \\LL
______:______q NAME :SPettijohn:eh:KMBlack
- FJHebdon
- C mes :
-DATE :7/54/86
- 77Ll/86
- 7/3i/86
- R/l' 4B6 0FFICIAL RECORD C0FY
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1 A500/C601 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 f
This report documents the results of a study completed by the Office for Analysis and Evaluation of Operational Data (AE0D) with regard to particular operating events. The findings and reconsnendations do not necessarily represent the final position or requirements of the responsible program office nor.the Nuclear Regulatory Commission.
I Dy 4deaco/3f>
TABLE OF CONTENTS Pa5Le EXECUTIVE
SUMMARY
1 1.
INTRODUCTION...................................................
5 2.
DESCRIPTION OF THE EVENT.......................................
6 2.1 General...................................................
6 2.2 Chronology of Events......................................
6 3.
ANA LYS IS OF THE EVENT..........................................
8 3.1 Seed Rupture..............................................
8 3.2 Contamination and Personnel Uptakes.......................
9 4.
LICENSEE AND SOURCE MANUFACTURER ACTI0NS.......................
11 4.1 Licensee Actions..........................................
11 4.2 Source Manufacturer Actions...............................
11 5.
FINDINGS.......................................................
12 6.
CONCLUSIONS AND RECOMMENDATIONS................................
13 7.
REFERENCES.....................................................
14 APPENDIX A................................................
15 APPENDIX B................................................
16 APPENDIX C................................................
18 APPENDIX D................................................
21 t
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w 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.
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.
l
- 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.
- During 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.
. 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.)
l 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 l
is associated with:
1 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.
l l
l
- As of the date of this report the University of Cincinnati has not resumed l
the practice of reusing the seeds to treat multiple patients.
l
. 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 normally communicated to purchasers or other users of the seeds, specific instructions and safety precautions for reusing the seeds be communicated.
- NRC regulations do not require such a leak test.
~.
' 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.
,-....,r
-- - e
. 1.
INTR 000cl10N 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 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.) 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 uses.
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 must 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:
I 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 treatment 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 l
furnished by the manufacturer in the leaflet or brochure that l
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 implant 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 u.se 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 low activity iodine-125 sdeds (0.1-1 millicurie) as permanent brachytherapy implants.
2.2 Chronology of Evprts The following excerpt from the NRC Region III 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 millicuries 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 conunittee approval prior to use of the seeds (Appendix A).
J
. (5) On Monday (day 10), 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 revealea 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.
(12) On Wednesday (day 27), a thyroid bioassay on patient 3 J
revealed a burden of 557 microcuries.
(13) On Thursday (day 28), determination of area contamination 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.
. 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 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.
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) l 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.
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 were contained in catheters'that were stained from having been implanted in a 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.
. 3.2 Contamination and Personnel Uptakes The removal of the seeds on both day 11 and day 18 was done in the brachy-therapy source room in an open area that was not ventilated by a fume hood.
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 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 Region III inspection report noted that the background radiation level in the BSR 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 with cotton swabs or similar material and later counting the wipes, were not done. Good health physics practices and NRC regulatory requirements indicate that, under the circumstances, wipe surveys should have been performed to look for contamination.** In addition, good health physics practices indicate that, since removal of the seeds from catheters involved non routine handling of the 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 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, 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
- 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 outward, indicating a positive differential pressure between the BSR and 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.
. 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 container 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 room 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.
l Wipe tests taken in the brachytherapy source room on day 29 showed contamina-l 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 ft3 (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.
. 4.
LICENSEE AND SOURCE MANUFACTURER ACTIONS 4.1 Licensee Actions As a result of the source rupture, the University of Cincinnati suspended the useofhighintensityiodine-125seedspendingtheinvestigationoftheevent (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 involving 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 Lloard (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 whca 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-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 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.
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.
l l
l l
i I
14 -
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).
(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 to Darrell Wiedeman, Chief, Materials Radiation Protection Section, NRC (Region III).
1
~ ~ -
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n
-~,,--
. APPENDIX A P otocol for the use of 125 1 sealed sources for imp la nt into pat ient 's tumor:
1.
Upon recolving 125 1 shipment A.
A wipe test is first nede inside the source contalm'r bottle by Rediation Safety to detect possib le leakage of the sealed sc< - e.
B.
Calibration of each shipment of sealed sources is done by Radiet tom Oncology with a dose calibrator using an N8S standard source (a;L r table late 1983).
2.
Preparation for implants A.
The 125 1 seeds are loaded into shiel ded cartridges or af terloading devices by Radiation Oncology technologist /staf f/ residents with special tools designed for handling the seeds standing behind a lead shiel d or wearing a lead apron.
B.
Af terloading, the ins trumnnts 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 sterilized for 10 minutes.
3.
During implant in patients and immediately post imp lant A.
The instruments used in the imp la nt should be ronitored with a thin window counter af ter the imp lant to check for leakage contamination due to possib le mechanical damage to the seeds.
B.
The suct ion ap para tu s, tubing and traps, including the Foley bag are checked for loose 1251 seeds and r emoved appropriately for disposal by Radiation Oncology or Radiat ion Safety.
l 4.
Post implant monitoring - per Radiation Saf ety regarding exposure to personnel 5.
If leakage is discovered A.
Upon recei ving shipment - container is to be sealed and disposed j
appropriately by Radiat ion Saf ety.
B.
During handling of seeds - al l personnel or pat ients involved are to have their urine checked and undergo thyroid counting to monitor exposure.
6.
All unused 125 1 seeds are to be returned to Radiation Saf ety for disposal 125 except for reusab le high activity 1 seeds (40 MCI), which are to be stored in Radiation Oncology's shleided safe.
activity is below 10 MCI each.
These will be returned when the 7.
All operators and technologists handling 1251 seeds will wear finger badges.
~
,, APPENDIX B l-125 Seeds No.6702 Description Warnings 3 125 Seeds 6702 consist of a welded titanium capsule containin9 todine.125 aesorbed on anion exchange resin spheres.
~ The 1 125 Seed titanium capsule has excellent corrosion resistance, but it is attacked by concene ated hydrochloric acid.
I.125 Seeds have been designed not to be used in a concentratec 1.e25 essees.d
..... nen nee o os awa
- r..
iii..
PrecaullOnS i
N__
/
Preparation for Use/ Sterilization l.125 Seeds are radioactrve and appropsiate precautions must be f[D h'
taken when handling these tources. Alt steps of the implantatiors o.s mm
.(
Sf procedure should be planned in advance to minimize radiation
{
l exposure to personnel, consistent with published exposure limits.
Personnel monitoring is requerea for incsividuals working with 1 12 4.s mm Seeds. A film badge or TLD dosimeter worn on the body and, for
/
handling, a ring badge will provide adequate detection.
Physical Characteristics 3 125 Seeds are provided in a glass vias which should be
- lodine-125 has a half. life of 60 2 days and decays by electron maintained in a lead vialcontamer for staarage. Wnen transportmg
,papture witn the emission of cryaracteristic photons and Auger seeds within the hospital premises, an appropriate carrier with electrons. The electrons are absorbed by the titanium wall of adequate shielding should be used.
the 8-125 Seed. The, principal photon emissions are 27.4 and.
All manip'ulations irwolving i.125 Seeds should be carried out 35.5 key a. rays and a 35.5 kev gamma.
behind shielding of 'sucts size and thickness as will adecuately To correct for the physical decay of lodine.125. the decay factors shield the operator. DIRECT CONTACT WITH THE SOURCES at selected days af ter the assay date are shown iri the table below.
SHOULD BE AVOlOED.In acejition.I.125 Seeds should be oecercaars sedia.425. Hait use so.2 cars handled only with forceps, with as muc:a distance as oractical o.c,
c c.,
between sources and the operator.l.125 SEEDS SHOULD NO) o.r.
r.cs.,
para reci,
BE PICKED UP WITH THE HANDS.
o.
...toco 35..............
... c.ssi 8 125 Seeds are NOT sterife when shippied and as such must be
" Qg y
" ['-
sterilized with steam (autoctave) or ethytene oxide (E01 before 3
6'
.. '...."..... o.s : 2E.... [ o.s33 42
.E ((c s17 implantation. Regardless of the merfiod selected. l.125 Seeds a.
- 44.................csos should be placed in an adequately shienced container prior to io.
.. o est 46
.......... c.s es placement in the sterifization chamber. Manipulation of the seco 12.
... o ari as.
... c.srs prior to or fotfowmg sterilization should be carried cut benitid g.
shieldmg of such size and thickness aswill adequately shield the e
se
.'.... o a i s 5 4 "...'.' * ~.'.T.* * *. c537 operator. in addition. l.125 Seeds shoued be handled only with 20.
........ o.7 9 4 ss.............. c s2s forceps,with as much distance as practical between sources anc 22.
..... o.77s 58
..c.ss3 the operator. Autoctaves should be equipped with traps or o*her 24
. c.75s so.
...... o soi 2e.
. o.74 52
............. c. 4 9o means to prevent seed loss through the drain hole.
2a.
.. o.724 54
............... o a rs 3125 Seeds have been designed to wittistand normat aatOctave so.
...... o 7cs es.................o. ass temperature and pressure variations from 121' C at 15 osi te 32.
...T. o ss2 ss.
. 0.4s7
.... o s76 70
............. 0. 4 4 7 138* C at 35 psi.1125 SEEDS ARE NOT INTENDED TO BE 34 STERILIZED USING DRY HEAT AND SHOULD NOT BE Radiation Protection SUBJECTED TO TEMPERATURES AND PRESSURES IN The half value thickness of lead fcr socine.125is 0.025 mm. Thus, a EXCESS OF THESE UMITS(138* C and 35 psi).
0.25 mm lead sheet wiis provide > 99% reduction in exposure.
I.125 Seeds should be autoefaved in bulk or individually in Actions appropriate containers of autoclave. compatible materials. Thes.
materiais include stainless s:eet. grass. nyton. and tefiott i.125 I.125 Seeds emit 27.4 and 35.5 kev x. rays and a 35.5 kev Seeds may also be autociaved in selected accessories to gamma. The cimical efficacy of the sources derives solely from commencally.availableimplanttools. Among enese accessories l
tne interaction of inese sonizing radiations with the tissue being are the stamless steet cartsidge of trie Mick apolacator and gun.
treated' and nylon and teflon tubing used as seed hoiders with Henschke and Scott applicators. When in doubt about the criemicat riature Dose distribution around eacn indivicual seed is not isotropic. This of these de'ed holders, either sterilize the materials witn ethylerie anisetropy snould be included in dose distribution calculations.
Oxide or autoclave a sample of the materials contammg dummy Titanium encapsulation' assures goed tissue compatibility and seeds before attemptmg to load wish radioactive seeds. 00 NOT resultsin a total self-absorption of approumately 16%.
AUTOCLAVE 8125 SEEDS IN PLASTIC TUBING OR OTHER PLASTIC CONTAINERS.
Indications Althougn 8 125 Seeds have a high structurat integrity. it is possit, 1 125 Seeds are indicated for interstitialtreatment of tumors which through rough handlerig. Sigts temperatures or crushmg that a have tr:e f ollowmg cnstacteristics: unresec'able. localized, and seed c uld leak or be rupturedelf sucts a rare occurrence does moderate radiosensitivity.
happen, the area should be closed oft the seeds packaged into a 1.125 Seeds may be used for selected radiation applications as sealed container and the area decontammated. Decontammatiori remova ble implants.
can be confirmed by taking wipe"sampfes of theimmed, ate area Personnel movement should be controlled to avoid seread of an.
l.125 Seed 5 ar e indicated to treat residual tumors followmg radioactive contaminaticin. Wnenever a sot:rce is damaged, completion of a course of externat tadestion therapy. in addition.
personnel workmg in the area should undergo a thyroid scan to recurrent tumors may be imolanted with s.125 Seeds.
assure that tney have not been contars.inated by contact. ingesta.
or mhalation of todme.125.
ContraindiCatiDn5 i
~
As with other brachytherapy sources treatment of tumorsin
,generativ ocor cono.t.on f ao u cerat.dm not recommended with
h8edical Products Division /3M g
TCAAP Now Brighton. Minnesota $5112
~j Certific'ation
'mS4963 70 4.9 lodi e-125 Sealed Sources For Medical Uses' 1 Sep.1983 Consignee:
UNIV CINCifmATI MED. CTR RADIGISOTOPE tA9 Address:
234 GOODMAN ST CINCINNATI. OH 45267 V
The following radioactive sources are certified by Minnesota Mining and Manufacturing Company (3M)1: have been subjected to the tests described below and to have been given the results listed.
Modef Number gy lot Number,
yg_g)g Ogantity 10 i
l Activity Range (mci)* 38 OM 3
Totas Activity (mca-390.O I
Assay Date g
J AII seeds have passed a leak test showing <0.005pCi of removable
- lodine activity. No other certification
~
is to be implied.
- By " mci" we mean " apparent activity in millicuries", which is descriptive of outpu; activity only and not the total quantity of I 125 contained within the titanium capsule of the Seed.
For accounting purcoses, the cuantity of I-125 contained in Model 6702 or Model 6711 Seeds is about 12 or l
1.6 respectively multiplied by the stated apparent activity in millicuries.
Read the reverse side of this form for information about Seed construction, method of calibration and l
definition of " apparent activity in millicuries".
- h.
- p.
)
(M7 _
bl 9 August 1984 h/
Ou ty Control Date
__v
e 4
,he,ollow,ng procedu,e is spect.1 -rd.r...,c.s
.re furnished by Phillip H. Cutin, supplied either sterile or M.D..a for informational nonsterite as Indicated on the purposes:
$PEClflCAflDN5 (All Dimensions are Nominal) product label.
Nonsterfte products, if intended for The Comatal Afterloading Implentetton or an aseptic Catalog Suture Catheter can be used for application, agli be cleaned Description Collar Catheter Length:
Number Implantion of redloactive Tip Diameter len,,
(pg,,
and sterillred petor to uses sources into brain tumors.
If your product is nonsterlie, Ca80035-08 Conalal Afterloading Clear t cm 16.5 cm 15 cm The ruter cetneter is
-g2 Catheter the cleaning and sterilisation generally placed to a tumor
-03 Radiopeave 2 cm 16.5 cm 15 cm procedures given below have target through a burr hole or been found effective and
-04 andlopeoue I cm 15.5 cm 2 7 cm twist dellt hole using a provided as a gulde.
are Radiopaque 2 cm 25 5 cm 27 cm stylet guided by computed-Special Order Devices are Manufactured 8 Distributed by:
tomography directed
$ffRitifATION sterectasy.
The catheter AMERICAN HETER-$CHVLTE gasses through the tillcon*
this product is recommanded Division of base before entering the Amerlean Hospital Supply Corporation for sinole use ontv.
It is Drain.
600 Pine Avenue recommended that each Coleta CA 13817 institution establish the L'h e n the catheter is at the efficacy of its sterlitration telephone (805) 967-3451 target, the allicone base is procedure by a method which gushed down to the skin or to includes t he st erli tr at ion of the skull.
It can then be en intentionally contaminated a
tutured in position, or, in proouct.
the case of the skull, it can Md bD glued to the bone with 00 Do not sterlitre in the biological adhesive.
- Then, packmanna system supplied.
the outer catheter is glued to the base with biological The following cleaning and s(hesive.
The stylet is
'}{}
.o removed and replaced with the sterillration techoloues have inner catheter containing the been found effective and are provideo as a guldet e
radioactive sources. The Inner catheter is secured to Remove the Heyer-Schulte the outer catheter with a drop Coastal Afterloading Catheter of bioloolcal adhesive.
from its package in a clean Hou SVPetlED environment using gloved hands.
Lint, fingerprints, talc and other surface Esch catheter is provided contaminants can cause foreign Inffwidustly wrapped in a body reactions. Utmost NON5fttitE condition, and caution should be taken to tensasts nf an esternal avold contaminants.
c$theter with tuturing fienge end two telescoping Internet estheters. All catheters must use en etcohol (ethyl or isopropyl) swab to remove olly Manufactured and Distributed by:
ts cleaned and steellised per ths Instructions below.
surface contaminants.
AMf tlCAN HETER.1CHOLfg 3>
Hand wash solled sillcone Olvision of e
9d e7hillip H.
Cutin, M.D.
American Hospital Supply Corporetton 90 devices for a maalmum of 15 University of California HJspitals minutes in a solution of mild 600 Pine Avenue Colete CA 93117 505 Parnassus surgical soap or a one percent ty Telephone (805) 967-3458 D!aartment of Neurosurgery antonic detergent. If it is
>m CCOM423 necessary to use a brush, only Sin Francisco, 94843 73
Functional failure of the Pe0 DUCT INr00MATION Dl1Ct05Utt catheter system que to separation of It s component International Customers -
parts can result in serious American Heyer-Schulte has Catelco Products Caughtln, Christopher T.,
Even esercised S. Douple, John W. Strohbehn, complicatlons. Catheters may reasonable care in Walter L. Eaton Jr.,
- 8. 5;uert migrate into other areas the choice of materials and for product information or to Trembly, and T.I. Wong, cousing 9erious harm to the manufacture of this product.
order directly, contact your
- gattent, American Heyer-Schulte local American Heyer-Schult.
" Interstitial Hyperthersle in Combinatlon wi th -
e sc lude s all marrant les.
d stributor or the Amerleen V.
=hether Srechytherapy," Redletony, 144 Infection le a common and empressed or implied Mueller international Customer (July 1945), 285-284.
serlous compliention of by operation of law or Service Department at 1500 a
other=ls*, including, but not Waukegon Road, McGew Park IL Chervulu, K.K.N.t "A new catheter system and is most limited to, any implied 60085 USA.
Telep%one (312) frequently caused by skin afterleedlng technique for contaminants. Septicemia, warranties of eerchantabilft?
473-3500, Teles (Twn) 110 Interstlttel Irradiation a sing or fitness.
Amerscen Heyer-210-195, which occurs most frequently redloettive microspheres.* Am Schulte shall not be lieble J. Roenteenol Radlun Ther NUCI In debilitated Infants, can for any incidental or in Canada, contact AH$/ Medical result from infections Med. 102: (8964), 192.
Specialties, Olvision of McGaw Consequential loss. damage or sav=nere in the body and may Supply Ltd., 2390 Aroentle develop alth few or no empense, derectly or Cohen, J.C.
and D.M.
- Skleroff, Indirectly erlsing from the -
poed, Mississauga, Onterlo, "A New Approach to the symptoms.
It may occur es e use of this product. American Canada L5N 3Pl.
Telephone result of a wound infeation.
infection, Heyer-Schulte neither (486) 821-9098.
Surgical-Radiologic Managene t in the event of en assumes nor of Sreest Cancer with removal of the catheter system authorlies any other Interstitlet Irldtum, geyegal is ledicated in addition to person to assume for it, any international C us t ome r s -
other or additional llebility
$p,clal Products of the Albert Clnsteln Medlcal the appropriate chemotherapy, Center, vol. 5, No. le I
or responsibility in RETURNED C000$ PotlCy connection with this device
- For information on speClel (December 1956).
g, yo Order devices, please Contact U.S. Customers
_Ps0 DUCT OeDE# INr0eMAfl0N the Customer Service Fletcher, C.H.,
and M.
I Stovaill "A study of Department et American Authorfration must be received U.S. Customers - CataloQ Heyer-Schulte, 600 Pine empIIClt dlstribution of from Americas Heyer-Schulte, Produc t s.
Avenue, Colete CA 93117 USA, radiation in Interstitial.
implantation." Redloloor, 78)
Olvision of American Hospital Telephone (805) 967-34$1, (1962), 766-782.
To order directly in the Telen (Twx) 910 334-3165.
Supply Corporation, prior to the return of merchandtse.
U.S.A., please Contact
- Grey, S.A., I. Sheldon, M. t*.
Marchandise retuened must have American V. Mueller, esclusive Ceutton* Federal law freedman, and A.R. Kagen:
all manufacturer's seals United States distributor for restricts this device to sale ~~~
of Interstittel redletion all "ftbrosarcome: A compilCatlon intact and De received within American Heyer-Schulte by or on the order of a
$$ dayt of date of involte to products with distribution physician, therapy for a beten centers In Irvine and Hayward be ellg ele te for credet or rtpleComent.
Returned CAs Orlando FLs Norcross CAg pfBLIOGRAPHy beamangloma occuring after 18 Ve8r**" I','
J.
tediolo22, O'
McGow Park IL3 9edford mas
~
products may be subject to tTI (1974) 60 bl.
restocklog charges.
Romulus Mis Minneapolls MN Awwe rd, H.K, J.M.V. Surgers, 1
Maryland Height s MOs Edi son and H,R. MarCuseg pThe NJ3 Columbus ohs Richardson Influence of tumor dose Gutin, Phillly M. and Ray M.
Int ernet tona l Customari Dormandy Jr., "A Conalal and Woodland TX.
specification on the early Catheter System for Autherfration for return of clinical resul,ts of merchandise should ha obtained U.S. Customers - 3 rectal _
Interstitlel radium tongue Afterloading Radioactive Sources for Interstitial reeducts implants" ERI I from your respective dealer.
conditions cated above (1974), 17 7-13 )B11 110 8 ffredistjon of Srein Tumors,"
Cther J. Neurosura, 56 (May 1987),
For Information on special else apply.
734-735.
Order deeltes, plessa Contact Caryulu, K.K.N.*
"An the Customer Servlce afterloading method for Cutin, Phillip M.
et al, Department of American Interstittel Implantellon of Heyer-Schulte, 600 Pine radioactive seed."
" Permanent and Removable Implants for the Orachytherapy Avenue. Coleta CA 93117.
Panminerva_Med. 13: (1978),
of Brain Tw= ors," m dletion.
foll-free telephone (800) 359 36).
e 235-5f38 Onco'0Gy, Biology, Physerj, 7:40 (October t il l ),
1371-1381.
e e
' 9 752
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- +, -, -, - - -
,e e.,
. A.PPENDI-X -0
. MiniMonitor 125
~ - - ~
Contamination Monitor C
/w.'.
Measureilow-level "'I surface N
- -/,g
.k'..~,
contamination quickly and accurately c'.
h..
Lw L.
- High sensitivity (lower detection limit-0.002 Ci).
('
h y
U2 e Three ranges (0 500, SK and 50K cpm).
f 2
4
- Large. area, screened detector permits contact surface measurements.
{j f
For the first time, a compact, sensitive monitor is avail-
. -T O g.-
able for the detection of 231 surface contamination levels as low as 0.002 pCi.
A large-area, thin-window GM detector, recessed in a conical housing on the back of the instrument, permits Detector: Halogen-quenched GM pancake tube,1.2* diam.
direct-contact measurements of surfaces.The maximum Readout: 2%~ analog meter, marked 0 to S00.
amount of removable contamination allowed * (0.005 Ranges: 0-500,0 5,000,0-50,000 cpm.
aCil is well within the detector limits of the unit. All Accuracy: 10% of full scale, surfaces as well as hands, clothing. shoes, etc., may be Controls: Off, Battery Test, x100, x10,21 tanges-all en routinely monitored by using this hand. held instrument.
one switch.
Lightweight (22 ounces) and portable, the monitor op.
Time Constants: 10 secs (x1): 2 sees (x10); 03 secs (x100).
erstes on 4 alkaline "AA" cells. All controls are con.
Ba t teries : Four "A A" alkaline cells (500. hour life).
veniently located on the instrument's face. An LED in.
Operating Tem perature:-20'C to + 55*C (-4 *F to + 130*F).
dicator flashes with each incident radiation pulse. The Temperature Dependence: ::15% 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 plastic response survey meter for radiation detection in the
- S'-
laboratory. The 3. range selector switch permits rapid
^ * ' ' ' ' ' '.'S"PPII'd II*.'c e ntamm. t. ion shield. License-changing of survey ranges. Radiation levels are read I*'
on a large 2%* meter. The monitor includes a plastic size:6 high x 3*+
wide x 2 thick. Weight:22 ounces.
contamination shield for protecting the detector hous-o3 572 MiniMonitor 125 Contamination Monitor 532 oo w
ing and a license-free radioactive source for checking the instrument's overall operation.
- Per NP.Cor Agreement State regulations.
9
. o en..
e w.P 4