Outpatient treatment of thyroid cancer using high doses of iodine 131

Objective: To develop a protocol for outpatient high-dose iodine 131 therap y to treat thyroid cancer, to allow therapy to be performed at the patient' s convenience and save considerable hospital costs without causing undue ra diation exposure to members of the public. Methods: The radiation safety ha zard - both external (from gamma rays emitted fr-om the patient) and intern al (from radioactive material in the patient's excretions) - can be calcula ted according to guides issued by the US Nuclear Regulatory Commission. The protocol aimed to produce an "occupancy factor" of 0.125 or less for the " critical person" (person caring most for the patient) for the entire 72-hou r period after administration of I-131. This is the equivalent of 3 hours p er day at a distance of 1 m from the patient. Results: Each patient's suita bility for outpatient therapy is determined on the basis of the patient's h ome environment, ability to understand the risks involved and likelihood of compliance, by the referring physician's opinion, through a self-report qu estionnaire and through a patient interview with the radiation safety offic er and the nuclear medicine physician. This protocol has been approved by t he Atomic Energy Control Board and has been used to screen 8 patients to da te, with 1 patient being denied outpatient treatment. Conclusions: Outpatie nt therapies with relatively high doses of I-131 can be performed safely. C are must be taken to ensure that the patient's home environment is suitable and that the patient can understand and comply with precautions, If extern al exposure can be minimized, only basic precautions are needed to ensure t hat internal contamination does not lead to excessive doses to members of t he public.