Bone single-photon emission computed tomography (SPECT) combined with X-ray computed tomography (SPECT-CT) is expected to replace planar bone scintigraphy (BS) as the routine method for imaging bone metastases. In preparation for this change, this thesis aimed to optimize and validate novel SPECT-CT methods, including fast whole-body image acquisition using a cadmium-zinc-telluride (CZT) SPECT-CT system, reprojected bone SPECT-CT (RBS), and quantitative SPECT.

Fast image acquisition was optimized by comparing the sensitivity and specificity between SPECT images acquired from the same patients with 50-, 32-, 26-, and 16-min acquisition times. RBS was validated by comparing the sensitivity and specificity between BS and RBS images of the same patients. Quantitative SPECT was validated by comparing standardized uptake values (SUVs) of the same bone metastases between SPECT and positron emission tomography (PET).

The average patient-level sensitivities for the 50-, 32-, 26-, and 16-min images were 88, 92, 100, and 96%, respectively, and the corresponding specificities 78, 84, 84, and 78%, respectively. The average patient-level sensitivities for BS and RBS were 75 and 87%, respectively, and the corresponding specificities 79 and 39%, respectively. SUVs correlated strongly (R2 ≥ 0.80) between SPECT and PET.

Whole-body bone SPECT-CT can be performed using a CZT system in less than 20 min without loss of diagnostic performance. Whole-body bone SPECT-CT can be reprojected into planar images with excellent sensitivity but limited specificity for identifying bone metastases. The strong correlation of SUVs between SPECT and PET demonstrates that SPECT SUVs are feasible for uptake measurements in bone metastases.