Interactive software automates personalized radiation safety plans for Na131I therapy.

Abstract

NRC regulations have liberalized the criteria for release from control of patients administered radioactive materials but require written radiation safety instruction if another individual is expected to receive more than 1 mSv. This necessitates calculation of expected doses, even when the calculated maximum likely dose is well below the 5 mSv release criterion. NRC interpretations of the regulation provide the biokinetic model to be used to evaluate the release criterion for patients administered Na131I, but do not provide guidance as to either the specifics of minimizing the dose of others or the length of time restrictions should remain in effect. Interactive software has been developed to facilitate creation of radiation safety plans tailored to patients' expected interactions. Day-by-day and cumulative effective exposures at several separation distances, including sleeping, are presented in grid format in a graphic interface. In an interview session, the patient proposes daily contacts, which are entered separately for each individual by point-and-click operation. Total dose estimates are accumulated and modified while negotiating contact schedules, guided by suggested age-specific limits. The software produces printed radiation safety recommendations specific to the clinical, dosing, and social situations and reflective of the patient's choice of combinations of close contact with others. It has been used in treating more than 100 patients and has been found to be very useful and well received.