Whole-body single photon emission computed tomography/computed tomography for assessment of oncological bone disease - is an extended field of view (from vertex to toes) of clinical value?

Objectives: Whole-body single photon emission computed tomography/computed tomography (WB-SPECT/CT) is useful for diagnosing bone metastases. When performed on a dual-headed gamma camera, this may cover from clavicles to proximal femurs due to time constraints. In contrast, the novel 360 o cadmium-zinc-telluride scanner can perform WB-SPECT/CT (from vertex to toes) in approximately 20 min. The aim was to assess the prevalence of additional findings above the clavicles and below the lesser trochanters and the prevalence of incidental findings in the CT component.

Methods: Retrospective study of 117 WB-SPECT/CT scans for oncological bone assessment over a 4-month-period. Scan analysis was performed by two independent experienced radionuclide radiologists.

Results: The male:female ratio was 71:46 and the mean patient age was 68 years. The primary malignancies were predominantly prostate 65/117 (55.6%) and breast 40/117 (34.2%). There were additional findings of malignancy above the clavicles in 16/116 scans (13.8%) and below the lesser trochanters in 16/117 scans (13.7%). Two cases in the 'above the clavicles' group were suspected solitary metastases, whereas four cases in the 'below lesser trochanters' group were bone metastases at risk of pathological fracture. Incidental findings of clinical significance included suspected new malignancy in 11/117 (9.4%).

Conclusion: A WB-SPECT/CT (from vertex to toes) oncological bone protocol is useful for the detection of additional findings of clinical significance above the clavicles and below the lesser trochanters. Reviewing and reporting the CT findings in SPECT/CT is important.