[Study and implementation of a computerized program for personalized prescriptions for patients treated with...

Iodine-131 (131I) therapy is widely used to treat some thyroid diseases such as hyperthyroidism and thyroid carcinoma. The discharge of a radioiodine treated patient is a potential problem for the radiation protection of the general population. To keep the absorbed dose to the general population as low as possible, patients are given some recommendations, on discharge usually a quite standard list of behaviors to avoid for an amount of time depending only on the administered activity. Thus, recommendations usually consider neither the individual kinetics of 131I nor disease type, while both factors account for major differences in iodine uptake and retention. We investigated the feasibility of customizing recommendations according to recent Euratom guidelines.

Individual 131I kinetics can be evaluated from previous work characterizing dose rate decay as a function of time for different thyroid diseases, together with measurements of iodine uptake or dose rate to the patient. Based on individual kinetics, the committed effective dose to the general population is calculated according to the kind of relationship with the patient, resulting in different amounts of time spent near him/her.

The calculation procedure was implemented in a user-friendly software which requires input of few data and measurements to give each patient a customized list of precautions. Using the program on patient's discharge takes no longer than 10 minutes. The precautions are in good agreement with those reported in the literature.

We have been using our program for nine months. Data show that most patients treated for thyroid cancer must follow the recommendations for a shorter time than hyperthyroid patients. The program is suitable for routine use in a nuclear medicine department.