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
August 13, 1997
NRC INFORMATION NOTICE 97-64: POTENTIAL PROBLEMS ASSOCIATED WITH LOSS
OF ELECTRICAL POWER IN CERTAIN TELETHERAPY
UNITS
Addressees
All U.S. Nuclear Regulatory Commission medical teletherapy licensees.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to a potential problem associated with loss of
electrical power in the Theratron 1000 teletherapy unit manufactured by
Theratronics International, Limited. 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 NRC requirements; therefore,
no specific action or written response is required.
Description of Circumstances
An Agreement State licensee notified the State authorities that a
misadministration had occurred during a teletherapy treatment. Specifically,
while a patient was being treated, a thunderstorm resulted in a loss of
electrical power twice during the treatment period. A hospital technologist
reset the machine both times to allow treatment continuation. When the
treatment ended, the patient commented that the wrong site may have been
treated. The technologist then noticed that the light field was not aligned
to the intended treatment site.
The hospital's Radiation Safety Officer and technologist were able to recreate
the problem only when the technologist was lying on the table in the position
that was occupied by the patient being treated and power was interrupted. The
table subsequently moved approximately 20 centimeters (8 inches) in the
longitudinal direction. The licensee then calculated that the patient
received approximately 130 rads to the wrong treatment site. The hospital
notified the manufacturer, Theratronics, of the event. After an
investigation, the manufacturer concluded that the licensee had not operated
the teletherapy unit in accordance with the operating instructions. The
manufacturer, however, noted the problem and flagged the operating
instructions for possible improvement during the next general revision of the
operator's manual.
9708070081.
IN 97-64
August 13, 1997
Page 2 of 2
Discussion
All licensees are reminded of the importance of ensuring the safe performance
of licensed activities in accordance with NRC requirements, the requirements
of their licenses, and the instructions in the manufacturer's operator�s
manual. Section 4.7 of the operator�s manual discusses actions that must be
taken if there is a loss of electrical power. These actions include removing
the patient from the treatment room and realigning before resuming treatment.
In addition, Section 4.7 contains a warning that states:
[i]f Table 23T is equipped with the �free float� option, when the power
is off, the lateral and longitudinal motions will be free. Take care to
prevent injury when unloading they should
clearly understand the manufacturer operator�s manual. Additionally, in cases
where questions or problems arise concerning unit use, users should contact
the manufacturer and should remember the potential for causing a significant
radil device user facilities are now
subject to mandatory Food and Drug Administration (FDA) adverse event
reporting requirements for medical devices. Information concerning FDA�s
mandatory reporting requirements can be obtained by contacting the Center for
Devices and Radiological Health, Office of Surveillance and Biometrics,
Division of Surveillance Systems at (301) 594-2735. Since the FDA mandatory
reporting requirements may not be applicable to all medical device events, FDA
also depends on information voluntarily provided by device users because they
are often the first to recognize medical device related hazards. Any concerns
that licensees may have pertaining to the safety or quality problems
associated with medical devices can be voluntarily reported to the FDA by
calling MedWatch at 1-800-FDA-1088. Voluntary reports can be submitted
anonymously.
This information notice requires no specific action or written response. If
you have any questions about the information in this notice, please contact
the technical contact listed below.
signed by F.C. Combs for
Donald A. Cool, Director
Division of Industrial and
Medical Nuclear Safety
Office of Nuclear Material Safety
and Safeguards
Technical contact: Nader Mamish, NMSS
301-415-6316
E-Mail: [email protected] Coordinated with Theratronics & FDA
