United States Nuclear Regulatory Commission - Protecting People and the Environment

Technical Assistance Request, Medical College of Virginia, Richmond, VA, Policy Guidance Concerning Use of Xenon-133 in Saline

HPPOS-319 PDR-9307060010

See the memorandum from J. E. Glenn to D. M. Collins dated June 25, 1993.

This memo responds to a technical assistance request from Region I, dated May 29, 1992, concerning a request from the Medical College of Virginia for policy guidance. The licensee requested clarification whether xenon-133 (Xe-133) in saline should be considered a gas and the subsequent applicability requirements of 10 CFR 35.205. The licensee intended to administer Xe-133 in saline intravenously to patients for cerebral blood flow studies. These patients cannot be moved into a room at negative pressure for the studies without creating a potential health risk.

Xe-133 dissolved in saline is technically not a gas. Therefore, the licensee does not need to adhere to the requirement to administer radioactive gases only in rooms that are at negative pressure compared to surrounding rooms as stipulated in 10 CFR 35.205 (b). However, in case of a spill of the saline solution before administration, the xenon will be released from the suspension as a gas. The licensee should indicate if the xenon is dissolved in saline under pressure. If so, additional precautions may be necessary if the vial containing the Xe-133 is inadvertently punctured. The rebreathing system should recapture all exhaled xenon. It will be essential for the licensee to post spilled gas clearance times and have adequate safety precautions to ensure minimal exposure of personnel and patients in the Neuroscience Intensive Care Unit.

Therefore, the requirements of 10 CFR 35.205 (a), (c), (d), and (e), that stipulate air concentrations be within 10 CFR Part 20 limits, calculation and posting of spilled gas clearance times, monthly checks of the operation of the reusable collection systems, and measurement of ventilation rates in the area each six month, should be instituted as part of the licensee's protocol for use of Xe-133 in cerebral blood flow studies.

Regulatory references: 10 CFR 35.205

Subject codes: 12.19, 9.1, 11.2, 11.3

Applicability: Byproduct Material

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