03-30091. Gamma Knife Center of the Pacific Environmental Assessment and Final Finding of No Significant Impact; Exemption

The U.S. Nuclear Regulatory Commission is authorizing the Gamma Knife Center of the Pacific, License No. 53-11966-02, an exemption to 10 CFR 35.655, for 120 days to permit the licensee to continue the medical use of its gamma stereotactic radiosurgery unit beyond the interval specified in the regulation for full inspection and servicing.

Environmental Assessment

Identification of the Proposed Action

The Gamma Knife Center of the Pacific has a United States Nuclear Regulatory Commission (NRC) license (License No. 53-11966-02) that authorizes the medical use of a Leksell Gamma Stereotactic Radiosurgery unit. The licensee has requested, in a letter dated September 8, 2003, that the NRC grant a temporary exemption from the requirements of 10 CFR 35.655(a) in order to continue treating patients until the manufacturer's scheduled source replacement in February 2004. This regulation requires that all stereotactic radiosurgery units be fully inspected and serviced at source replacement or at intervals not to exceed 5 years whichever comes first.

The licensee had the Leksell Gamma Stereotactic Radiosurgery unit installed in October 1998 and treated the first patient December 1, 1998. The period of time between manufacturer's scheduled source exchange and the last full inspection service before treatment of the first patient exceeds the required 5 year interval. The licensee in e-mails dated September 11 through 18 clarifies that the manufacturer has indicated the semiannual service, which was last performed July 29, 2003 on the licensee's unit, includes all the tests that can be performed without disassembly of the unit. Such disassembly is not advised at any time other than source replacement because a new Leksell Gamma Stereotactic Radiosurgery unit can contain 6,000 curies of cobalt 60 and disassembly can create high radiation fields unless it is performed at source replacement.

Need for the Proposed Action

The exemption is needed so that Gamma Knife Center of the Pacific can continue to provide medical treatment to its patients. The exemption would allow the Gamma Knife Center of the Pacific to use the gamma stereotactic radiosurgery unit until the manufacturer can remove the sources and perform the full inspection and servicing during source replacement. This inspection and service can only be performed after source removal during source replacement. The exemption would permit continued use of the unit and provide needed timely patient therapeutic services without interruption. The source exchange and inspection service is scheduled for February 2004. The 120-day duration of the exemption allows for flexibility if there is a delay in the manufacturer's ability to ship the sources and perform the source exchange. NRC inspections since 1999 have not identified any violations or medical events associated with the use of the gamma stereotactic radiosurgery unit.

Environmental Impacts of the Proposed Action

The gamma stereotactic radiosurgery unit contains 201 cobalt 60 sealed sources and no material will be released into the environment. All the cobalt-60 is contained within the gamma stereotactic radiosurgery unit, as verified by periodic source leak tests performed by the licensee. The proposed action does not increase public radiation exposure. There will be no impact on the environment as a result of the proposed action.

Alternatives to the Proposed Action

As required by Section 102(2)(E) of NEPA (42 U.S.C. 4322(2)(E)), possible alternatives to the final action have been considered. Only the manufacturer can perform the source exchange and the licensee has already scheduled the source exchange at the manufacturer's earliest available time. The only alternative is to deny the exemption request and to require the licensee to put the sources in storage until the source exchange and full inspection service can be performed. This option would not produce a gain in protecting the human environment, and it would negatively impact the licensee's provision of medical care to its patients.

Alternative Use of Resources

No alternative use of resources was considered due to the reasons stated above.

Agencies and Persons Consulted

No other agencies or persons were contacted regarding this proposed action.

Identification of Source Used

Letter from the Gamma Knife Center of the Pacific, to U.S. Nuclear Regulatory Commission, Region IV, dated November September 8, 2003.

E-mails from Ronald Flick to Jackie Cook, NRC, dated September 11, 12, and 18, 2003.

Finding of No Significant Impact

Based on the above environmental assessment, the Commission has concluded that the proposed action will not have a significant effect on the quality of the human environment. Accordingly, the NRC has determined that a Finding of No Significant Impact is appropriate and preparation of an environmental impact statement is not warranted.

The licensee's letter and e-mails are available for inspection, and/or copying for a fee, in the Region IV Public Document Room, 611 Ryan Plaza Drive, Suite 400, Arlington Texas 76011. The documents are available electronically for public inspection from the Publically Available Records (PARS) component of NRC's Documents Access and Management System (ADAMS), accession number ML03300150. ADAMS is accessible from the NRC Web site at http://www.nrc.gov/​reading-rm/​adams.html.

Dated at Rockville, Maryland, this 26th day of November, 2003.

For the Nuclear Regulatory Commission.

Roberto J. Torres,

Section Chief, Material Safety and Inspection Branch, Division of Industrial and Medical Nuclear Safety, Office of Nuclear Material Safety and Safeguards.