Part 21 Report - 1996-860
ACCESSION #: 9612180245
William Beaumont Hospital
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.
Purushottam Sharma, M.S.
Charles Jones, Nucleotron Service Engineer
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