Página 263 - irpa

263 ST 3.3 – Protección radiológica en medicina nuclear
RADIATION PROTECTION RECOMMENDATIONS FOR REALEASING
PATIENTS TREATED WITH 131I FOR THYROID CANCER:
A PATIENT SPECIFIC APPROACH
Mora Ramirez, Erick*; Salas Ramirez, Maikol
Caja Costarricense del Seguro Social. Costa Rica.
* Autor responsable, email: erick.mora.ramirez@gmail.com
The Nuclear Medicine Department at the San Juan de Dios Hospital has considered radiation
protection guidelines given by the IAEA for releasing patients after 131I Treatments for Thyroid
Cancer; in the Safety Report Series No. 63, “Release of patients after radionuclide therapy”,
published in 2009. However IAEA guidelines are based on the administrated activity and it does
not take into account bio-kinetics of 131I into patient body, distance between patients and its
relatives, etc. Our goal is to establish patient specific recommendations considering dose limits
to relatives and caregivers, also bio-kinetics of thyroid - extra-thyroid compartments; taking into
account NUGREG-1556, Vol 9, Rev. 2 from USNRC considerations. For 15 patients (Female
14), age range from 79-24 years old (mean 37); thyroid and extra-thyroid compartments
effective half-life have been estimated, occupation factor, distance and effective dose have
been set. Preliminary results for average data showed good agreement with IAEA guidelines for
ablation patients in restrictions for children under 2 years old, time off work and sleep apart,
however restrictions for children from 2 to 11 years old are not similar; on the other hand follow-
up patients, in our case means patients with recurrence or metastatic diseases, results are very
different from the IAEA guidelines for all restrictions which means that patients specific behavior
have to be take it into account. Therefore a method to establish patient specific radiation
protection recommendations can be applied in a Nuclear Medicine Department taking into
account bio-kinetics of 131I.