sup 89^Sr bremsstrahlung single photon emission computed tomography using a gamma camera for bone metastases

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