Comparison of I-131 sodium iodide thyroid uptake values using gamma camera and uptake probe

Learning Objectives Iodine uptake is an investigation to demonstrate the functional status of the thyroid gland, and can be performed using either gamma camera, or uptake probe. A gamma camera can be safely and easily utilized at nuclear medicine centers that do not have access to an uptake probe.

Summary: This study is aimed to investigate the ¹³¹I sodium iodide (IU) thyroid uptake of patients with hyperthyroidism using two different methods; the gamma camera (GC) and the uptake probe (UP). The results of the two different methods were compared. Ninety-nine patients were investigated. Fifty percent of all patients had Grave’s disease (GD), 28 (28.3%) had toxic adenoma (TA), and 21 (21.2%) had toxic multi-nodular goiter (TMG). The IU values at 4 hours were 32.52 ± 18.85 and 20.23 ± 11.89 respectively for UP, and GC. These two methods correlated linearly and very strongly (r= 0.94, p= 0.001). The following formula is used for transformation: y= 1.49x + 2.39; where x represents the 4 hour IU value using GC and y represents 4 hour IU value using UP. At 24 hours, IU values using GC and UP were 25.32 ± 8.89 and 45.93 ± 15.4 respectively. These two methods correlated linearly and very strongly, as well (r= 0.91, p= 0.001). The following formula is used for transformation: y=1.57x + 6.03; where x represents the 24 hour IU value using GC, and y represents 24 hour IU value using UP. The UP-IU at 4 hours, GC-IU at 4 hours, UP-IU at 24 hours, and GC-IU at 24 hours was higher in GD patients when compared to TA and TMG patients.