Estimation of Clearance Rate of Iodine-131 From Thyroid Cancer Patients Based on Individual Patient’s Characteristic.

Abstract Differentiated thyroid carcinomas (DTC) are the most frequent malignancies of the endocrine system in 2015 in Japan. The purpose of this study is to estimate clearance rate of Iodine-131 from thyroid cancer patients based on individual patient’s characteristics. Materials and methods: We conducted retrospective study including 87 cases with DTC who had received RAI from June 2016 till July 2018. Patients who had complete information on primary tumor size (PTS) as mentioned in their histopathology reports, TNM staging, serum TSH (uIU/ml), free-T3 (pg/mL), free-T4 (ng/dL), thyroglobulin level (Tg) (ng/ml) (one month before, on the day of the treatment, and one month after receiving RAI), anti-Tg antibodies (IU/mL), dose of Levothyroxine (before and after RAI), as well as renal function (creatinine, BUN, eGFR), exposure rate (µSv/h) and taken dose (mCi) were included in our study. Results: Univariate analysis showed significant associations of effective half-life with several factors (gender, body height, body weight, eGFR, size of tumor, dose of Levothyroxine, free-T3 one month after receiving RAI). Conclusion: Effective management of these factors could help the doctors to optimize the occupancy of isolated rooms with higher output, but also reduce the operational cost of the hospital and improving the comfort to patients.