Effects of Hydration on Radioactivity Excretion and Patients Isolation after Radioiodine Therapy
Nazenin İPEK IŞIKCI1,Mustafa DEMIR2,Mohammad ABUQBEITAH2
1Department of Computer Engineering, Nisantasi University, Faculty of Engineering and Architecture, Istanbul-Türkiye
2Department of Nuclear Medicine, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul-Türkiye
DOI : 10.5505/tjo.2022.3720 OBJECTIVE
In thyroid cancer, radioiodine is widely used for thyroid ablation with variable activity range 1110- 11100 MBq (30-300 mCi). The aim of this work was to evaluate the dose rate of the discharged patients and the impact of hydration on the patients whose dose rate is close to the discharging dose limit.

A total of 303 patients undergoing 131 therapies were recruited in this study. Dose rate measurements were performed 22?24 h after radioiodine uptake. The patients with a dose rate <30 µSv/h were discharged. Whereas, those with a 30?40 ?Sv/h dose rate were asked to drink further 1.5-2 liters of water for 4-6 h. Then, post-voiding dose rate measurements were repeated.

Consequently, the patients administered with 1111?2775 MBq (30-75 mCi) were discharged after 24 h. Among the patients treated with 3700 MBq (100 mCi), 21/29 patients (72.4%) had a dose rate between 30 and 40 ?Sv/h and they were released within 4-6 h after drinking 1.5?2.0 liters of water. For the patients treated with 5555 MBq (150 mCi), 23/32 patients (71.8%) whose dose rate between 30 and 40 µSv/h were similarly discharged after drinking extra 1.5?2.0 liters of water within 4?6 h. Moreover, the patients who were subjected to 7400?11100 MBq (200?300 mCi) 131I therapy were not asked to drink extra water as the dose rates measured at the end of 24 h were >40 ?Sv/h and they were discharged later.

Consequently, it was manifested that around 72% of thyroid cancer patients who underwent radioiodine therapy had a dose rate level 30?40 ?Sv/h after 24 h and could be discharged early by drinking 1.5-2.0 liters of water within 4-6 h. Keywords : Dose rate; hydration; isolation time; radioiodine therapy; thyroid cancer