Dosimetric and Risk Impact of Clinical I-131 Dose Scheduling in Thyroid Cancer: Single vs. Fractionated Therapy

Research Article
Mosab Bashir, Ali S Ali and Alnazier O Hamza
DOI: 
http://dx.doi.org/10.24327/ijrsr.20251608.0084
Subject: 
Health Science
KeyWords: 
Iodine-131 therapy, dose fractionation, thyroid cancer, dosimetry, radiation risk, OLINDA/EXM
Abstract: 

This study compares organ doses, effective doses, and cancer risk in thyroid cancer patients treated with either a single 3700  MBq (100  mCi) or three times of 1110  MBq (30  mCi) ) I-131 doses 15 days apart. Nineteen patients (16 females, 3 males) underwent whole-body scans at 24 and 48 hours post-administration after one month using 37 MBq of I-131. Organ dosimetry was calculated with OLINDA/EXM and cancer risks estimated using ICRP 103. Fractionation lowered organ doses and cancer risk by ~10% in both sexes. Females patients’ consistently experienced higher absorbed doses and risks. The lungs and bladder wall were the largest contributors to overall risk.. Fractionated I-131 therapy modestly reduces exposure and supports sex-specific planning.