Comparison of bone SUV obtained from different SPECT/CT systems.

Objective: In bone scintigraphy, it is difficult to compare quantitative values, such as standardized uptake value (SUV), obtained from 2 different single-photon emission computed tomography combined with computed tomography (SPECT/CT) devices owing to differences of imaging acquisition and analysis methods. Therefore, the purpose of this study was to compare the SUV obtained from different SPECT/CT devices using the ratio to normal bone, and to analyze the correlation between them.

Subjects and methods: A total of 27 prostate cancer patients who underwent bone scintigraphy either using Symbia T16 or Symbia Intevo (Siemens Medical Solutions, Erlangen, Germany) were retrospectively analyzed. In each patient, spherical voxels of interest were placed on the following 5 reference points: humeral head (humerus), femoral neck (femur), lower part of the ilium (ilium), first lumbar vertebra (L1), fifth lumbar vertebra (L5), and the maximum SUV (SUV_max) and average SUV (SUV_ave) of these regions were measured.

Results: The mean and variance of SUV_ave (humerus) was the smallest on both SPECT/CT. To compare the SUV obtained from the 2 devices, the SUV_ave ratio and SUV_max ratio of each region were calculated as the SUV_ave and SUV_max of each region divided by the SUV_ave of the humeral head in each patient. Median values of the SUV_max ratio and SUV_ave ratio of each region showed similar tendencies in both devices, with correlation coefficients between 0.93 and 1.19.

Conclusion: Our results demonstrated that by expressing the quantitative value of SUV_ave of each region as a ratio to the SUV_ave of the humeral head, accumulation in the targeted bone can be compared even when the imaging acquisition and analysis methodsare different.