48 subjects (31 women; 17 men; mean age 54±11; age range 15-80 years) with clinical suspicion or diagnosis of endocrine and neuroendocrine tumors had 50 SPECT/CT scans performed on the dual head Siemens Symbia T6 SPECT/CT scanner between January 2010 and March 2012. Thirty-two of these scans were Tc 99m MIBI, 5 were post treatment I-131 scans, 8 were In-111 Pentetreotide scans, and 5 were I-123 MIBG scans.
All SPECT scans were performed using a 128x128 matrix, 30 seconds /stop, total of 64 stops obtaining 128 projections, using non circular orbit. All SPECT data was processed using filtered back projection, frequency cut off 0.5, order 5, and a second reconstruction using OSEM, 8 iterations and 16 subsets.
Tc-99m Sestamibi (MIBI) SPECT/CT scan: After intravenous administration of 1110 MBq Tc-99m sestamibi, immediate SPECT/CT images were obtained from the lower face to mid chest using a low energy collimator, energy setting at 140 KeV with 20% window. Following a 2-hour delay, repeat SPECT/CT images were obtained of the same level. MIP (maximum intensity projection) reconstructions were performed and the early and late images were compared side-by-side for distribution and retention of radiotracer.
I-131 Post treatment scan with SPECT/CT scan: One week after oral administration of therapeutic dose of I-131 raging between 1776–6031 MBq, anterior and posterior whole body planar images were obtained using a high energy collimator, energy settings at 364 KeV with 20% window and camera speed of 8 cm/min. SPECT/CT images of the neck as well as the regions with equivocal findings were obtained.
In-111 pentetreotide scan with SPECT/CT scan: 4 hours after the intravenous injection of the 222 MBq In-111 pentetreotide, whole body anterior and posterior planar images were obtained using a medium energy collimator, energy settings at 172 KeV and 247 KeV with 20% window and 10cm/min. Approximately 24 hours later, repeat whole body images in the anterior and posterior views, as well as SPECT/CT images of the regions with equivocal findings were obtained.
I-123 MIBG (Metaiodobenzylguanidine) scan with SPECT/CT scan: 24 hours after the intravenous injection of 400 MBq I-123 MIBG, whole body anterior and posterior images were obtained using a low energy high resolution collimator, energy settings at 159 KeV with 20% window, and 9cm/min. In addition SPECT/CT images of the regions with equivocal findings were obtained.
CT scan: After oral administration of 20 cc gastroview mixed with 900 cc clear non-carbonated liquid over the course of an hour, axial CT images of the area of interest were obtained using 2.5 mm collimation, 130 kVp, mAs of 20-60 for neck, and mAs of 40-80 for chest, abdomen, pelvis and extremities, depending on body habitus, and pitch of 0.8 with a Siemens Symbia T6 SPECT/CT scanner.
32 subjects with elevated parathyroid hormone levels had 32 MIBI scans, all of which were before a parathyroid surgery. In these subjects lesion detection and localization with SPECT alone was compared to SPECT/CT. Findings were correlated with pathology. For the other scans, including five post treatment I-131 scans in 5 subjects with papillary thyroid cancer, eight In-111 Pentetreotide scans (the primary tumor was well differentiated pancreatic endocrine neoplasm in 4 subjects, well differentiated neuroendocrine neoplasm of small bowel in one subject, carcinoid tumor of the small bowel in one subject, gastrinoma in one subject, and gastric carcinoid tumor in one subject), and five I-123 MIBG scans in 4 subjects with suspicion of primary or recurrent pheochromocytoma, lesion detection, characterization, and localization were compared between planar and SPECT and planar and SPECT/CT images. The planar images and the SPECT alone component of the studies were interpreted and the findings were recorded. Planar and SPECT/CT images were then evaluated and the findings were recorded. Planar image findings and SPECT findings were compared to planar and SPECT/CT findings. All findings were correlated with histopathology when available, or radiologic follow-up.