The improved accuracy of planar bone scintigraphy by adding single photon emission computed tomography (SPECT-CT) to...

Planar bone scintigraphy (PBS) is a standard radiological technique to detect skeletal metastases from prostate cancer (PC), the addition of SPECT-CT to PBS improves its diagnostic accuracy. The aim of this study was to assess the additional value of targeted SPECT-CT with PBS in detecting skeletal metastasis form prostate cancer, considering resource implications in an Irish hospital setting.

54 PC patients with increased radiotracer uptake on PBS were retrospectively recruited from 2012 to 2013. All underwent targeted evaluation with SPECT-CT. PBS and SPECT-CT images were reviewed by two nuclear medicine radiologists and reported independently. The final diagnosis was made based on the CT finding corresponding to the area of radiotracer uptake.

The mean age was 70.9 years (48-88 years) and median PSA at presentation was 13.9 ng/ml (4.2-215 ng/ml). 68.5 % (n = 37) men received treatment for PC while 31.5 % (n = 17) patients had not received treatment prior to PBS. 164 areas of increased radiotracer uptake were identified on PBS; 13 areas were characterised as metastatic on SPECT-CT; iliac bone (n = 3), ribs (n = 1), skull (n = 2), sacrum (n = 1), ischium (n = 1), femur (n = 3), thoracic spine (n = 1) and cervical spine (n = 1). 151 areas were characterised as benign on SPECT-CT. One area of increased radiotracer uptake in the ribs was subsequently described as indeterminate after evaluation with SPECT-CT.

SPECT-CT improves the diagnostic accuracy of PBS in detecting skeletal metastasis from PC and is superior to PBS alone in differentiating benign from malignant lesions. Notwithstanding resource implications of increased cost, specialist equipment and specialist manpower hours; we recommend the use of SPECT-CT in conjunction with PBS for targeted evaluation of suspicious bony lesions in this cohort of patients.