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U.S. NUCLEAR REGULATORY COMMISSION
REGION 111
Docket No: 030-19162 License No: 22-00187-54
Report No: 030-19162/98001(DNMS)
Licensee: University of Minnesota W168 Boynton Health Service 410 Church Street, S.E. Minneapolis, MN 55455
Location: Lewis Hospital for Companion Animals College of Veterinary Medicine St. Paul, MN
Dates: August 26 - 31,1998
Inspector: John D. Jones, Senior Radiation Specialist
Approved by: Geoffrey C. Wright, Chief ' Materials inspection Branch 2 Division of Nuclear Materials Safety
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EXECUTIVE SUMMARY I
University of Minnesota inspection Report 030-19162/98001(DNMS)
This special inspection included a review of the circumstances, root and contributing causes, and licensee corrective actions with regard to a non-reportable event. The event involved an individual who, while operating the cobalt-60 teletherapy unit in the Hospital for Companion Animals, failed to carry out a required procedure to clear all other personnel from the . | teletherapy and adjoining rooms prior to depressing the " acknowledge" switch on leaving the therapy room. Failure to ensure allindividuals were clear of the room prior to depressing the acknowledge switch is a violation of 10 CFR 36.67(b)(1). |- The failure to carry out the required procedure resulted in an individual being left in the cat iodine treatment room, a laboratory attached to the cobalt therapy room, without any other means of egress from the room except through the therapy room housing the irradiator. The contributing causes of the violation were the apparent preoccupation of the irradiator operator with preparing the patient (dog) set up for treatment and human error in failing to check the cat | room to see if anyone was in the room prior to pushing the survey acknowledge switch on the
way out. Another contributing cause to this violation was the survey acknowledge switch , location at the end of the maze instead of in the cat room where other individuals routinely ! work. The inspection did not identify any individuals who would have likely received a significant radiation exposure due to the failure to carry out the required proc. Jure. The training that the individual who remained in the irradiator facility received was shown to be ) adequate in that the individual recognized the potential for the inadiator to be in ust, and took appropriate actions.
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Reoort Detajls
I 1.0 Program Summary
NRC License No. 22-00187-54 authorized the University of Minnesota (licensee) to > possess and use a cobc!1-60 teletherapy device containing up to 12,000 curies of cobalt-60 for treatment of animals and for irradiation of animals to study the effects of ) radiation on animals. The source strength as of January 27,1998, was 5,740 curies. This inspection reviewed only the licensee's activities associated with the event where | an individual remained in the irradiator cat treatment room during the operation of the irradiator.
The responsibility for possession and use of the cobalt-60 teletherapy unit is The University of Minnesota's, Radiation Safety Officer (RSO), Jerome W. Staiger. | J 4 | Licensed operations at Lewis Hospital for Companion Animals are performed under the ' supervision of Daniel A. Feeney, D.V.M., Gary R. Johnson, D.V.M., or Patricia A. Walter, D.V.M. The licensee had established a radiation safety committee to review and approve all uses and users of licensed material and provide oversight of the | radiation safety program.
2.0 Sequence of Events
a. Inspection Scope (87100)
The inspector reviewed the sequence of events that resulted in the failure to carry out a required procedure of checking the cobalt-60 facility for other individuals who might be in the facility. The failure to conduct a thorough surveillance resulted in an individual being left in the cat iodine treatment room. The review included licensee processes and procedures, an observation of the facilities, independent measurements, and interviews of licensee personnel.
b. Observations and Findinos
Based on interviews of licensee personnel involved directly and peripherally with the incident, the inspection determined that the following chronology of events occurred. | The descriptions are limited to those activities that were relevant in reconstructing the l likely exposures to workers and the public.
On Tuesday, August 18,1998, an authorized teletherapy operator and two other individuals were in the teletherapy room preparing a patient (dog) for a radiation treatment. The two other individuals with the operator were veterinarian anaesthesiologist technicians there to assist in preparing the patient. Neither of the anaesthesiologist technicians were trained in use of the irradiator and would not be expected to know to clear the area prior to a treatment. One had never been in the therapy room before and the other only a couple of times.
During the same time that the individuals were preparing the patient for treatment, a technician assigned to work in the iodine-131 cat treatment room, which adjoins the i irradiator room, was performing her duties in the room.
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Following preparation of the patient, the teletherapy unit operator failed to follow the operating procedures and did not perform the required physical check of the iodine-131 cat therapy room prior to exiting the treatment room and beginning the therapy treatment. Failure to perform the check resulted in minor radiation exposure to a veterinary radiology technologist who was in the cat therapy room during the treatment. 10 CFR 36.67(b)(1) requires that before exiting from and locking the door to the radiation room of a panoramic irradiation prior to a planned irradiation, the irradiator operator shall visually inspect the entire radiation room to verify that no one else is in the room. The operator's failure to visually inspect the entire area is a violation of 10 CFR 36.67(b)(1). i i immediately after the event, the operator and the individual who had been in the facility | during the time of the event reported the incident to the Manager of Technical Services at the Veterinary Teaching Hospital. The radiation protection division staff were notified of the event at about 11:00 a.m. on August 18,1998, by the manager of Veterinary Radiology Imaging Services. Radiation protection division staff immediately reviewed the event to determine if the individual was exposed to harmful amounts of radiation. | The staff determined, by reproducing the treatment procedure using the same treatment parameters and a dog scatter phantom, that the individual by staying in a remote comer of the cat treatment room received less than one millirem exposure (Attachment 1). The low dose to the individual was also confirmed by having the body and extremity dosimeters read by the badge supplier immediately. The amount of dose | received by the badges was less than the minimu.m sensitivity of the badges (approximately 10 millirem).
Although not required by regulation, the licensee reported the event to the Region ||| NRC office at approximately 4:00 p.m. (CT) on the same day of the event.
. The inspector reviewed the sequence of events with the RSO and reviewed training ! provided workers involved with the operation of the teletherapy facilities. Allindividuals were trained in accordance with license requirements. Each person is required to take an examination at the end of the training and pass the examination with satisfactory completion of 90 percent. An annual refresher training is given by the RSO.
| Interviews with various staff were performed by the inspector. The individual who was in the cat room during the treatment of the patient was familiar with the radiation therapy protocol and stated that normally the operator would come to the door of the cat room and announce that it was time to leave the irradiation facility. She went to the , | door and realized that the individuals who had been setting up the patient for treatment | were no longer in the therapy roorn. She did not see the prime alert monitor light come I on but went immediately to the far east comer of the room for the duration of the treatment (1.43 minutes at 80 centimeters (cm) source to surface distance using a 6 X 6 cm field) to protect herself from radiation.
The operator, according to the Director of Technical Services, was terminated as an
, employee of the hospital on August 18,1998, following the event. The termination of
- the operator was related to work performance prior to and including the event.
' The RSO conducted further tests on August 28,1998, with an integrating rate meter to : determine the dose that could have been received by the individual had she attempted
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to exit the facility instead of staying in the cat room (Attachment 2). These tests indicate that even if the individual had lingered just in front of the cat room door (position 1) for the entire duration of the treatment of 1.43 minutes, the dose that would have been received by the individual would have been no more than 5.9 mR (Attachment 2).
c. Conclusions
The inspection determined that the operator failed to carry out a required procedure to clear all other personnel from the teletherapy and adjoining rooms prior to depressing the acknowledge switch on leaving the therapy room. Because the person who remained in the cat room was properly trained, she did not go near the irradiator during the event. Consequently, no one was exposed to excessive amounts of radiation.
3.0 Licensee investigation and Corrective Actions
The licensee identified the root cause of the event. The root cause was determined to be inattention to responsibilities on the part of a teletherapy operator. Possibly contributing to the reason for the event was the location of the survey acknowledge switch at the end of the maze instead of inside the cat treatment room. The licensee immediately took steps to ensure that the event is not repeated. This included ordering the survey acknowledge switch be moved to a location inside the cat treatment room so that the presence of anyone in the irradiator facility will be known by the operator and a meeting was scheduled with all teletherapy facility staff to review the event and ensure that all staff are aware of the absolute requirement that all steps of the operating procedure are followed.
Conclusions
The licensee's investigation effectively identified the root and contributing causes of the event. Corrective action appears appropriate and adequate. I
s' Exit Meeting Summary
On August 31,1998, the inspector conducted an exit summary to discuss the NRC's findings with regard to the event and violation. The summary included the likely sequence of events, the root and contributing causes to the incident, the likely exposures to personnel and the public from the incident, the identified violation, the NRC's Enforcement Policy, and the licensee's proposed corrective actions. The licensee agreed with the information discussed ' and did not identify any of the information as proprietary in nature.
Attachments: 1. Mock Treatment Procedure Diagram No.1 2. Mock Treatment Procedure Diagram No. 2
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PARTIAL LIST OF PERSONS CONTACTED |
Licensee |<
! Katy Bend-Rubinstein, Technologist (Authorized User) Pat Berzins, Director of Technical Services Lewis Hospital for Companion Animals Tony Crimi, Veterinarian Anaesthesloiogist Technologist | Connie Eshenko, Veterinarian Technologist Cindy Henrickson, Technologist (Backup Authorized User) ~ Anne Smith, Technician 'Jerome W. Stalger, Radiation Safety Officer University of Minnesota Fay Thompson, Ph.D., Director, Environmental Health & Safety, University of Minnesota
, Brian Vetter, Health Physicist University of Minnesota Debra White, Supervisor of Technologists Heidi Wilcox, Technologist (Authorized User) Chris Wright, Veterinarian Anaesthesiologist Technologist
State of Minnesota Dept. of Radioloaical Health
Tim Donakosky I
INSPECTION PROCEDURE USED
IP B7100: Appendix F
ITEMS OPENED, CLOSED, AND DISCUSSED
Opened
030-00842/98001 VIO Failure to visua ly inspect the entire radiation room to verify that no one else was in the room prior to operating the irradiator. |
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030-19162/98001 VIO Failure to document training of irradiator operations.
Discussed
None
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