太田 誠一朗

Strontium-89 chloride (Sr-89) bremsstrahlung single photon emission computed tomography (SPECT) imaging was evaluated for detecting more detailed whole body Sr-89 distribution. Sr-89 bremsstrahlung whole body planar and merged SPECT images were acquired using two-detector SPECT system. Energy window A (100 keV +/- A 50 %) for planar imaging and energy window A plus adjacent energy window B (300 keV +/- A 50 %) for SPECT imaging were set on the continuous spectrum. Thirteen patients with multiple bone metastases were evaluated. Bone metastases can be detected with Tc-99m-HMDP whole body planar and merged SPECT images and compared with Sr-89 bremsstrahlung whole body planar and merged SPECT images. Based on the location of metastatic lesions seen as hot spots on Tc-99m-HMDP images as a reference, the hot spots on Sr-89 bremsstrahlung images were divided into the same bone parts as Tc-99m-HMDP images (a total of 35 parts in the whole body), and the number of hot spots were counted. We also evaluated the incidence of extra-osseous uptakes in the intestine on Sr-89 bremsstrahlung whole body planar images. A total of 195 bone metastatic lesions were detected in both Tc-99m-HMDP whole body planar and merged SPECT images. Detection of hot spot lesions in Sr-89 merged SPECT images (127 of 195; 66 %) was more frequent than in Sr-89 whole body planar images (108 of 195; 56 %), based on metastatic bone lesions in Tc-99m-HMDP whole body planar and merged SPECT images. A large intestinal Sr-89 accumulation was detected in 5 of the 13 patients (38 %). Sr-89 bremsstrahlung-merged SPECT imaging could be more useful for detailed detection of whole body Sr-89 distribution than planar imaging. Intestinal Sr-89 accumulation due to Sr-89 physiologic excretion was detected in feces for 4 days after tracer injection.