United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9612180245    


William Beaumont Hospital

Royal Oak

                            December 10, 1996

U.S.  Nuclear Regulatory Commission

NRC Document Control Desk

Washington, D.C.  20555-001

SUBJECT:  Potential Reportable Item (10 CFR Part 21.21)

          NRC License No. 21-01333-01

A potential reportable item, as regulated by 10 CFR Part 21.21,

"Notification of failure to comply or existence of a defect in its

evaluation," was identified on November 29, 1996 when our Nucleotron HDR

Microselectron malfunctioned as follows.  On Friday, November 29, 1996,

there were no problems experienced during the daily quality assurance

tests performed prior to patient treatment.  On Friday afternoon, a

patient with a carcinoma of the prostate was treated with the HDR-RAL

(high dose rate remote afterloading device) unit with Ir-192 (4.2 Curie). 

Thirteen needles were placed into the treatment site (i.e., the prostate)

and the position was verified to be in accordance with the treatment

plan.  The treatment plan specified dwell times for each of five dwell

positions within each needle.  The treatment parameters were verified in

accordance with our Quality Management Program and the treatment

commenced at 2:44 p.m. The source progressed as programmed from dwell

position nine through dwell position one in the first twelve needles.  At

2:59 p.m., after the source had progressed through two of the five

programmed positions for the last needle (i.e., dwells nine and seven in

needle thirteen), the dosimetrist bumped the tabletop on which the HDR-

RAL control unit is placed, and this caused the control unit to

temporarily lose communication with the HDR-RAL device delivering the

treatment to the patient.  The physicist was watching the control unit

display at the time of the event and observed that the source had at the

moment completed the programmed dwell time for position seven of needle

thirteen.  At the same time the radiation source retracted from the

patient into the safe as verified audibly on the intercom and visually on

the video monitor (i.e., the gold hand crank attached to the drive motor

was observed as it rotated and retracted the source into the safe).  The

physicist immediately verified that the source was fully retracted into

the safe via the radiation monitor.

The control unit regained communication and began printing previously

printed information.  The physicist then turned the control unit key from

the "treatment" position to the "prepare" position.  A patient survey was

completed which verified that the source had retracted.  The physicist

reviewed the treatment tape which documented the dwell time treated for

dwell positions nine and seven in needle thirteen.  The dwell time

treated, however, for position five (i.e., when the event occurred) was

not printed on the treatment tape.  Because the physicist was observing

the HDR-RAL control console at the time of the event, she knew that dwell

position five had not received any of the programmed dwell treatment time

within one second.

3601 West Thirteen Mile Road  Royal Oak, Michigan 48073-6769  (313) 551-


CORRECTIVE ACTIONS: Full communication was restored between the control

unit and the treatment unit and the physician authorized user decided to

complete the treatment by reprogramming the console to treat the last

three dwell positions in needle thirteen (dwell positions five, three and

one).  Treatment was completed in accordance with the written directive. 

Nucleotron service was contacted immediately.  On Sunday, December 1,

1996, the authorized Nucleotron service engineer replaced the control

unit microcomputer board and the control unit power supply.  The

communication between the control unit and the treatment unit was

thoroughly tested and functioning properly.  Prior to patient treatment,

the physicist tested and verified the source position, accuracy and

linearity.  All of the daily quality assurance checks were completed

without a problem.

This incident would not have caused a recordable event or

misadministration since the source immediately withdrew into the safe. 

The treatment console, however, did not print out the time parameter for

the dwell position when the event occurred.  If the physicist had not

been watching the control unit at the time of the event, then it would

not have been possible to determine how long the source had remained at

dwell position five of the thirteenth needle.  The service engineer for

Nucleotron, however, thought that this time parameter may have printed

out after the event, if the treatment console had not been turned from

the "treatment" position to the "Prepare" position.  A copy of the

treatment tape printout is included in the attachment.


Cheryl Culver Schultz, M.S.

Radiation Safety Officer

CC.  Darlene Fink-Bennett, M.D. 

     Alvaro Martinez, M.D.  

     Elizabeth Mele, M.S.

     James Safran

     Purushottam Sharma, M.S.

     Charles Jones, Nucleotron Service Engineer



Page Last Reviewed/Updated Wednesday, February 12, 2020