Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555
December 17, 1992
NRC INFORMATION NOTICE 92-84: RELEASE OF PATIENTS TREATED WITH TEMPORARY
IMPLANTS
Addressees
All Nuclear Regulatory Commission Medical Licensees
Purpose
The purpose of this notice is to inform licensees about concerns about
releasing brachytherapy patients without positive assurance that all implant
material (sources) have been removed from patients before their release.
These concerns encompass all brachytherapy procedures, including both manual
and remote afterloading techniques, using temporary implants. It is expected
that recipients will review the information for applicability to their
facilities and consider actions, as appropriate to avoid similar problems.
However, suggestions contained in this information notice are not new NRC
requirements; therefore, no specific action or written response is required.
Description of Circumstances
According to preliminary information that the Nuclear Regulatory Commission
received, an outpatient, being treated with an Omnitron Model 2000 High Dose
Rate (HDR) Afterloading Brachytherapy treatment system, at a freestanding
cancer center, was returned to a nearby nursing home, after treatment, with
the source remaining in the patient's body. The treatment took place November
16, 1992; the patient died November 21, 1992. Based on the patient's medical
records, the preliminary conclusion of NRC's consultant physician is that the
patient either died as a result of exposure to radiation, or that radiation
exposure was a major contributor to her death. He noted that the symptoms and
timing of the symptoms were consistent with severe, acute radiation syndrome.
Until the source -- approximately 4 curies of iridium-192 -- was removed from
the nursing home, after the patient's death, it subjected nursing home
residents and staff, as well as visitors, to radiation exposure. Radiation
doses to these members of the public are still being evaluated.
Cancer center personnel experienced difficulty with source placement in one of
the patient's five treatment catheters. This catheter was removed and the
patient returned to the nursing home, with the remaining four catheters in
place. Subsequent investigation after the patient's death found that a short
piece of the cable containing the iridium source had broken off and remained
in one of the catheters. Although a wall-mounted area monitor alarmed when
the treatment was completed, the licensee's staff believed the device was
emitting a false signal and chose to ignore it. Also, no survey of the
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patient was conducted, using a hand-held survey instrument, to determine if a
source remained in the patient, as required by 10 CFR 35.404(a).
A second incident was reported on December 7, 1992. A source again separated
from the drive cable on a Omnitron Model 2000 Unit, during brachytherapy
treatment of a patient, and lodged in the catheter, external to the patient.
In this instance, the physicist detected the source separation during the
treatment; he cut the catheter behind the source and immediately removed the
patient from the treatment room. The remaining portion of the catheter was
then removed from the patient and both the catheter and patient were scanned
with a survey instrument, to confirm that no part of the source remained
within either the catheter or patient.
Additionally, failure to perform proper radiation surveys, after treatment of
the patients with low-dose manual brachytherapy procedures, has led to loss of
control of one or more sources. NRC has received several recent reports of
such incidents, where the sources were eventually discovered in normal trash,
at a disposal facility.
Discussion
The NRC and the U. S. Food and Drug Administration are conducting ongoing
investigations of the cause of the failures associated with the Omnitron Model
2000 Unit. Until failure analysis information is available, it is unclear
whether the manufacturer will be required to recall the device, implement
design modifications, and/or conduct field retrofits to prevent the recurrence
of the problem. Consequently, all patient treatments using this
manufacturer's system must be viewed as having a high risk for similar
failures. Although NRC has no recent reports of similar failures of other HDR
models, such failures are possible. Because of the severe consequence of the
loss of control of one of these high-activity sources, users of all HDRs need
to be especially vigilant, in all of their operations, to minimize the effects
of any machine or procedural errors that could lead to loss of control of the
source.
Preliminary information, from the NRC investigation team at the cancer center
site involved in the November 16, 1992 incident, is that the room monitor
often produced false alarm indications; thus licensee personnel considered it
to be unreliable. It would appear that licensee personnel had been
conditioned, by repetitive false alarms, to ignore any information provided by
this primary radiation safety device. This device was used in place of a
portable radiation survey instrument, needed to conduct surveys required by
10 CFR 35.404(a).
Based on what is presently known about this incident, it is clear that if
proper radiation surveys of the patient had been made, before releasing the
patient from the facility, the consequences of this incident would have been
largely avoided. Although rare, the loss of control of one or more of these
high-activity radiation sources has great potential for causing injury or
death to patients, workers, and members of the public. Thus, because the
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consequences of such a loss of control are so severe, NRC, through this
information notice, is alerting all medical licensees and expects them to
consider all reasonable measures to minimize the possibility of such an event
ever occurring again.
All licensees are reminded that, in accordance with 10 CFR 35.404(a), the
licensee shall perform a radiation survey of all patients being treated with
brachytherapy sources, with an appropriate radiation detection or measurement
survey instrument, as specified in 10 CFR 35.420, to confirm that all sources
have been removed. For surveys associated with HDR procedures, the licensee
needs to use a portable radiation measurement survey instrument, capable of
measuring dose rates of 1 millirem per hour to at least 1000 millirem per
hour. It is important to use survey instruments with appropriate sensitivity,
since the high exposure rates associated with these sources can easily
saturate survey instruments, resulting in a false negative reading. This
survey is in addition to any indication of radiation levels provided by an
area radiation monitor. An area monitor provides an immediate indication of a
possible problem and thus serves a useful function as an early warning device.
However, it has neither the accuracy nor sensitivity required to comply with
the survey requirements of 10 CFR 35.404(a). The surveys shall be performed
immediately after completion of the therapy procedure before removal of the
patient from the treatment room, and appropriately documented in accordance
with 10 CFR 35.404(b).
It is expected that licensees will carefully consider the risks associated
with any procedure for which a decoupled source cannot be removed
expeditiously, from the patient, and placed in a shielded condition. NRC
Bulletin 92-03, dated December 8, 1992, requested all Omnitron HDR licensees
to have written emergency procedures describing actions to be taken, including
surgical intervention, should the source not return to the shielded container
at the conclusion of treatment. This would include providing for the
necessary staff and equipment to be immediately available, at the location
that the HDR procedure is performed, to implement the written emergency
procedures. Equipment should include shielded storage containers, remote-
handling tools, and, if appropriate, supplies (including scissors and cable
cutters) to help surgically remove sources from the patient. The emergency
source-removal procedure should minimize exposure to health-care personnel,
while maximizing safety to the patient.
The licensee should train personnel in both the routine use of brachytherapy
sources and devices and emergency procedures to return sources to a safe
shielded condition. This training should include emergency procedures and dry
runs, for coupled and decoupled sources that either remain in the patient or
remain exposed external to the patient. Licensees are also reminded of the
general requirements, such as, those contained in 10 CFR Part 19, 10 CFR
35.410, and license conditions, to have personnel trained to perform assigned
tasks in a manner that assures radiation safety. Training should be provided
immediately for new personnel, and retraining provided semiannually, for all
personnel. The records of this training should be maintained for a period of
three years.
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This information notice requires no specific action or written response. If
you have any questions about the information provided, please contact the
technical contact listed below, or the appropriate NRC regional office.
ORIGINAL SIGNED BY
Richard E. Cunningham, Director
Division of Industrial and
Medical Nuclear Safety,
Office of Nuclear Material Safety
and Safeguards
Technical contact: Robert L. Ayres, IMAB
(301) 504-3423
Attachments:
1. List of Recently Issued NMSS Information Notices
2. List of Recently Issued NRC Information Notices
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