The role of SPECT/CT in skeletal malignancies.

Bone scintigraphy is widely used for the detection of skeletal metastases, particularly in prostate and breast cancer. Although planar imaging is widely used, single-photon emission computed tomography (SPECT) imaging has demonstrated higher sensitivity. SPECT/CT imaging with the integration of CT and SPECT gantries has enhanced bone scintigraphy by providing accurate lesion localization and characterization of equivocal and solitary bone lesions. The key impact has been enhanced diagnostic confidence in the differentiation of benign from malignant skeletal lesions made possible by accurate localization of lesions to facet joints, vertebral bodies, or pedicles due to the exact coregistration of CT and SPECT as well as consideration of sclerosis or lysis within the lesion seen on CT. Several studies comparing planar, SPECT, and SPECT/CT in equivocal lesions have demonstrated a substantial improvement in specificity with SPECT/CT. This review highlights the key studies demonstrating the value of SPECT/CT in the evaluation of skeletal malignancies and shows clinical examples illustrating the impact of SPECT/CT in improved localization and characterization of skeletal lesions.