Evaluation of 131 I biokinetics and its absorbed dose in patients with metastatic differentiated thyroid carcinoma / 中华核医学与分子影像杂志

ABSTRACT

Objective To investigate the biokinetics of 131 I and its absorbed dose in patients with metastatic DTC. Methods Forty?one patients with metastatic DTC who were referred to 131 I therapy were prospectively recruited from September 2009 to September 2011. Scintigraphic images were serially acquired after the ingestion of 131I (3.70-9.25 GBq) to assess the biokinetics. CT was used to measure the masses of the DTC lesions. Calculation of absorbed doses to DTC lesions was based on the Medical Internal Radiation Dosimetry formula of the Society of Nuclear Medicine and Molecular Imaging. Kruskal?Wallis rank sum test was used to compare the differences of absorbed dose among different tumor deposits. Results In total, 59 io?dine?avid metastatic lesions (35 in cervical lymph node, 17 in lung and 7 in bone) in 41 patients were evalu?ated and the mean absorbed dose of DTC lesions was (10.4±6.5) Gy/GBq, with range of 0.1 to 136.2 Gy/GBq. The median absorbed dose was 11.3 Gy/GBq for lymph node metastase, 10.1 Gy/GBq for lung metastases and 9.6 Gy/GBq for bone metastases. There were no statistically significant differences in absorbed doses a?mong the metastases of lymph node, lung and bone ( Z=0.907, P>0.05) . Conclusion A wide inter?lesion variation of absorbed dose to metastatic DTC is observed.