Technical Assistance Request, Evaluation of Comments on NRC Information Not ice for Ophthalmic Applicators (NRC IN 90-59)
HPPOS-273 PDR-9306100107
Title: Technical Assistance Request, Evaluation of
Comments on NRC Information Notice for Ophthalmic
Applicators (NRC IN 90-59)
See the memorandum from J. E. Glenn to D. M. Collins dated
February 20, 1992. As requested in a Region II memorandum
from William Cline to J. E. Glenn, dated March 13, 1991
(Enclosure 1), the staff has reviewed the comments
presented by the Navy Radiation Safety Committee (Enclosure
2) concerning NRC Information Notice 90-58, "Improper
Handling of Ophthalmic Strontium-90 Beta Radiation
Applicators" (Enclosure 3). The following comments were
offered in response to the Navy Radiation Safety
Committee's concerns as denoted by NRC Region II (Enclosure
1).
Comment 2a: Issue of holding the eye open with tape during
the procedure.
NRC consultants tell us that tape is not an optimal means
of securing a patient's eyelid. The current medical
practice calls for the use of eyelid retractors. In order
to prevent Bremsstrahlung radiation, retractors made of low
atomic weight materials are preferred.
Comment 2b: Number of treatments per year versus use of
fingertips.
The number of treatments stated in case 2 was used as an
example and should not become the focus of the
illustration. The case emphasizes that a physician using
his/her fingers to secure the eyelid while administering
the treatment is improper procedure. Regardless of the
number of treatment applications, attention surrounding the
illustration should be directed towards ALARA guidelines
and the use of passive restraints such as eyelid retractors
to immobilize the eyelid.
Comment 2c: Interpretation of "extremity" limits.
Contrary to the Navy's criticism, contact with the source
tip of the applicator could indeed result in a radiation
dose in excess of NRC limits. We do not agree with the
concept that exposure with the Sr-90 eye applicator source
is tantamount to "hot particle" exposure because of
differences in geometry and dosimetry. In particular, the
area irradiated by a "hot particle" is substantially less
than one square centimeter, whereas the area irradiated by
a strontium-90 (Sr-90) eye applicator is greater than one
square centimeter. As defined in 10 CFR 20.1003, the
shallow-dose equivalent for skin or extremities applies to
tissue at a depth of 0.007 centimeters averaged over an
area of one square centimeter. Therefore this criteria
applies to Sr-90 eye applicators.
Comment 2d: Rules requiring personnel monitors.
The requirements for personal dosimeters discussed in the
information notice are in keeping with minimally accepted
ALARA guidelines.
The Navy's data indicates that their exposures do not
approach 10 CFR Part 20 minimum requirements for personnel
monitoring devices. However, it would be prudent health
physics practice to wear personal dosimeters because of
unanticipated exposures as well as planned exposures. Once
an individual has demonstrated sufficient knowledge and
skill using an applicator, exceptions might be considered.
If a licensee can clearly demonstrate that (1) the
radioactive material used is limited to the Sr-90 eye
applicator and (2) the resulting exposures did not reach
the limits set forth in 20.202 or 20.1502 (a), NRC would
consider licensee procedures without requirements for the
use of personal dosimeter devices on a case-by-case basis.
Comment 2e: Sterilizing agents.
Further review of the sterilization processes revealed that
the typical manufacturer's directions for sterilizing the
device are inconsistent with the Centers for Disease
Control's (CDC) recommendations. While this may be an
important point, the information provided in Item 1 of the
typical manufacturer's instructions was designed to call
the licensee's attention to the need for sterilization of
the Sr-90 eye applicators. The manufacturers may
ultimately modify their sterilization procedures to
coincide with those of the CDC.
Comments 2f and 2g: Corrosion and Calibration.
The information of concern in comments 2f and 2g was not
discussed in NRC IN 90-58. We are currently planning to
develop an information notice covering both the calibration
and possible corrosion of the device.
Comment 2h: Seventy years of use without an incident.
The three uses cited in the information notice represent
examples of significant potential exposures and, as such,
warrant notification of the licensees.
Regulatory references: 10 CFR 20.1, 10 CFR 20.202, 10 CFR
20.1101, 10 CFR 20.1502
Subject codes: 8.1, 8.3, 8.5
Applicability: Byproduct Material