TY - JOUR T1 - Clinical Usefulness of Fusion of <sup>131</sup>I SPECT and CT Images in Patients with Differentiated Thyroid Carcinoma JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1905 LP - 1910 VL - 44 IS - 12 AU - Yuka Yamamoto AU - Yoshihiro Nishiyama AU - Toshihide Monden AU - Yoshitaka Matsumura AU - Katashi Satoh AU - Motoomi Ohkawa Y1 - 2003/12/01 UR - http://jnm.snmjournals.org/content/44/12/1905.abstract N2 - Precise localization of the foci of 131I uptake for management of patients with differentiated thyroid carcinoma can be difficult because of a lack of anatomic landmarks. The objective of the present study was to demonstrate the clinical usefulness of 131I SPECT/CT fusion images in patients with differentiated thyroid carcinoma. Methods: CT and SPECT were performed 7 d after administration of a therapeutic dose of 131I to 17 patients with differentiated thyroid carcinoma. External markers were placed at 3 locations on the skin of the patient to adjust the sections of CT and SPECT in the same geometric plane. Fusion images were constructed by combining the digital CT and SPECT images on a computer workstation. The data from both planar and SPECT 131I images and CT images were first separately assessed by 2 nuclear medicine physicians. 131I SPECT/CT fusion images were then interpreted. Fusion images were considered to improve image interpretation in comparison with CT and scintigraphy separately when they provided better localization of sites of increased radiopharmaceutical uptake. Results: Both CT and 131I SPECT showed the pathologic sites in 5 of 17 patients (29%). Fusion images were considered to be of benefit in 15 of 17 patients (88%). In 4 patients, CT showed normal-sized lymph nodes, whereas 131I SPECT showed abnormal findings. In 3 patients with bone metastasis, fusion images confirmed the precision of the localization of abnormal 131I uptake. Five bone metastases and 1 muscle metastasis were occult and were not seen on the CT images. Finally, 131I scintigraphy findings were abnormal for 2 patients for whom the CT findings were initially considered normal. Fusion images confirmed the precision of the localization of physiologic 131I uptake. Conclusion: For registration of anatomic and functional images in fusion imaging, the method using external markers was simple and practical. 131I SPECT/CT fusion images using this technique may improve anatomically limited interpretation of 131I scintigraphy alone in patients with differentiated thyroid carcinoma. ER -