Two Bed SPECT/CT Versus Planar Bone Scintigraphy in Detection of Osseous Metastases in Patients With Genitourinary Malignancies

Genitourinary malignancies represent a heterogeneous group of diseases linked by anatomical and physiological function. Renal cell carcinoma (RCC); urothelial carcinoma of the bladder, ureter, and renal pelvis, and prostate adenocarcinoma (PC) are the most commonly encountered histological subtypes within this group. Planar bone scintigraphy (PBS) with di-phosphonate compounds is widely used, cost-effective and sensitive imaging modality for detecting osseous metastases especially in prostate cancer. However, it suffers from low specificity as well as low sensitivity in purely osteolytic lesions. Single-photon emission computed tomography (SPECT) is a three-dimensional acquisition method that has demonstrated greater sensitivity and specificity compared to planar images, especially for detecting vertebral metastases. The introduction of SPECT/CT images improves the lesion-to-background ratio, allows anatomic lesion localization, removes the superimposition of anatomical structures, such as urinary bladder activity, and provides anatomical data, thereby increasing the sensitivity, specificity and positive predictive value of bone scan. As the technology advances, current SPECT/CT machines have become capable of sequentially covering, and accurately merging, more than one field of view (FOV) in a reasonable time. In this study, we aim to compare the diagnostic performance of two-bed SPECT/CT images and planar bone scintigraphy in detection of bone metastases in genitourinary malignancies.