Abnormal right lower abdominal focal retention in the radioiodine (131I) whole-body scan

Abstract

SUMMARYObjective: Differentiated thyroid cancer (DTC) capture, organify iodine and have the ability to synthesize and release thyroglobulin. Because of this feature, DTCs can be treated with high doses of 131 I after total thyroidectomy. Whole body scan (WBS) with 131 I is a well-established method for the detection of metastatic or residual tumor sites in patients with differentiated thyroid cancer. False-positive radioiodine uptake has been reported in many organ systems. Our aim in the present study was to investigate whether an 'uncommon focal retention of radioactivity in right lower abdominal region' which we coincide only in woman patients in whole body scan with 131 I was a physiological finding. Method: A total of 405 consecutive patients with DTC who all were referred for either postablation or diagnostic whole body scan with 131 I, were included in the the present study. Results: A focal retention of radioactivity in right lower abdominal region was observed in 22 patients (5.4%) out of 405, in whom 14 patients had further radiological investigations. This group's mean age was 44 ± 13 years, ranging between 24 to 66 years. All patients were female. False positive contamination sources were clarified by careful examination of patients and further images. Abdominal ultrasound or abdominal CT was performed 12 of patients, and 18F-FDG PET/CT to two patients. However, no clear reason was found to explain relating uptake foci. Conclusion: We concluded that, a focal retention of radioactivity in right lower abdominal region in 131 I WBS would be a physiological uptake, however this finding needs clarification. Keywords