Therapy Dose Calculation in Hyperthyroidism Using the 3-Hour Early I -131 Uptake Measurements

Abstract

Therapy Dose Calculation in Hyperthyroidism Using the 3-Hour Early I -131 Uptake Measurements

Penpat              Pinyowatanasilp              BSc*

Somchai            Uaratanawong                 MD**

Division of Nuclear Medicine, Department of Radiology*

Department of Medicine** BMA Medical College and Vajira Hospital

Objective: The purpose of this retrospective study was to assess the feasibility of using the radioactive iodine uptake (RAIU) at 3 hours (3RAIN) value in the calculation of   ¹³¹ I treatment dose in hyperthyroidism patients.

Methods: A group of 361 hyperthyroidism patients were randomly divided into two groups (180 and 181 patients) Data from the first group were analyzes to find a mathematical equation describing relationship between the 3RAIU and 24RAIU by linear regression analysis. Similar manner was also performed between 24RAIU and 48RAIU. The predicted 24RAIU and the predicted   ¹³¹I treatment doses were calculated for the second group of patients based on the relationship equation. Linear regression analysis was also employed to determine statistically significant relationship.

Results: The regression relationship equations  were 24RAIU = 32.5 + 0.702 (3RAIU), r = 0.85 (p