Prediction of Absorbed Dose to Normal Organs in Thyroid Cancer Patients Treated with 131I by Use of 124I PET and 3-Dimensional Internal Dosimetry Software

Journal of Nuclear Medicine

John L. Humm¹  Keith S. Pentlow¹  Arif Sheikh¹  Katherine S. Kolbert¹  Steven M. Larson¹  Joel R. Pearson¹  Ronald D. Finn¹ 

关键词: ¹³¹I normal organ dose;    thyroid cancer;    ¹²⁴I PET;    radioimmunotherapy;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

The objective of this work was to determine normal organ 131I dosimetry in patients undergoing radioiodide therapy for thyroid cancer by use of serial scanning with 124I PET. Methods: A total of 26 patients who had papillary and follicular metastatic thyroid cancer and who were already enrolled in a Memorial Sloan-Kettering Cancer Center 131I thyroid cancer protocol were selected for this study. Imaging before 131I therapy consisted of multiple, whole-body 124I PET studies over a period of 2–8 d, an 18F-FDG PET scan and, for some, a diagnostic CT scan. With a set of in-house–developed software tools (3-dimensional internal dosimetry [3D-ID] and Multiple Image Analysis Utility [MIAU]), the following procedures were performed: all PET emission and transmission and CT image sets were aligned; half-life–corrected tomographic images of 131I activity were integrated voxel by voxel to produce cumulated 131I activity images; and the latter images were, in turn, convolved with a 131I electron–photon point kernel to produce images of 131I dose distribution. Cumulated activity values and calculated residence times obtained from our patient-specific dosimetry software (3D-ID) were used as inputs to OLINDA, and volume difference–adjusted comparisons were made between the mean dose estimates. Results: With 3D-ID, dose volume histograms and mean doses were calculated for 14 organs, and results were expressed in Gy/GBq. The highest mean dose, 0.26 Gy/GBq, was seen in the right submandibular gland, whereas the lowest mean dose, 0.029 Gy/GBq, was seen in the brain. Conclusion: This is the first comprehensive study of normal organ dosimetry in patients by use of a quantitative tomographic imaging modality.

【 授权许可】

Unknown