Quantitative Bone SPECT/CT Imaging

Bone scans were performed on a dedicated SPECT/CT system (Symbia Intevo, Siemens Medical Solutions AG, Erlangen, Germany) equipped with a low-energy high-resolution collimator. Planar images were acquired from anterior and posterior with a continuous table feed of 20 to 25 cm per min (ca. 1.000.000 cts) using a 1024 × 256 matrix and a 20% energy window around the 140 keV peak. Tracer activities of 713 ± 15 MBq [Tc^99m]-DPD were injected intravenously prior to bone scintigraphy SPECT imaging as recently described^{15 (link)} was performed using a 180° configuration, 64 views, 20 s per view, 256 × 256 matrix and an energy window of 15% around the 99mTc photopeak of 141 keV. Subsequent to the SPECT acquisition, a low-dose CT scan was acquired for attenuation correction (130 kV, 35 mAs, 256 × 256 matrix, step-and-shoot acquisition with body-contour). SPECT/CT images were reconstructed with the iterative xSPECT/CT QUANT algorithm (eight iterations, four subsets, 3.0 mm smoothing filter, and a 20 mm Gaussian filter) using a 3% National Institute of Standards and Technology (NIST) traceable precision source.