Nuclear Imaging for Bone Metastases in Prostate Cancer: The Emergence of Modern Techniques Using Novel Radiotracers

Abstract

Accurate staging of prostate cancer (PCa) at initial diagnosis and at biochemical recurrence is important to determine prognosis and the optimal treatment strategy. To date, treatment of metastatic PCa has mostly been based on the results of conventional imaging with abdominopelvic computed tomography (CT) and bone scintigraphy. However, these investigations have limited sensitivity and specificity which impairs their ability to accurately identify and quantify the true extent of active disease. Modern imaging modalities, such as those based on the detection of radioactively labeled tracers with combined positron emission tomography/computed tomography (PET/CT) scanning have been developed specifically for the detection of PCa. Novel radiotracers include 18F-sodium fluoride (NaF), 11C-/18F-fluorocholine (FCH), 18F-fluordihydrotestosterone (FDHT), 68Gallium and 18F-radiolabeled prostate-specific membrane antigen (e.g., 68Ga-PSMA-11, 18F-DCFPyL). PET/CT with these tracers outperforms conventional imaging. As a result of this, although their impact on outcome needs to be better defined in appropriate clinical trials, techniques like prostate-specific membrane antigen (PSMA) PET/CT have been rapidly adopted into clinical practice for (re)staging PCa. This review focuses on nuclear imaging for PCa bone metastases, summarizing the literature on conventional imaging (focusing on CT and bone scintigraphy—magnetic resonance imaging is not addressed in this review), highlighting the prognostic importance of high and low volume metastatic disease which serves as a driver for the development of better imaging techniques, and finally discussing modern nuclear imaging with novel radiotracers.

PSMA-Directed Theragnostics: Transforming Prostate Cancer Landscape

“…19,20 These include 68 Gallium (Ga)-and 18 Fluorine ( 18 F)-radiolabeled PSMA (e.g., radiotracers 68 Ga-PSMA-11, 18 F-DCFPyL and, more recently, 18 F-PSMA-1007 that combine the high specificity of the antibody/minibody tracers with a superior biodistribution. [20][21][22][23] Evidence from the literature suggests that these radiotracers can detect PCa relapses and metastases with high contrast by binding to the extracellular domain of PSMA, followed by internalization. 20,21 DIAGNOSTIC APPLICATIONS OF PSMA HYBRID IMAGING…”

Biological and Clinical Aspects of Metastatic Spinal Tumors

“…Among the imaging tests performed to detect metastases, it is the most sensitive. Scintigraphy also enables depicting the entire skeleton in one examination [ 132 ]. However, the disadvantage of this method of tissue imaging is its low specificity, which means that the anomalous image acquired does not have to be caused by neoplastic metastases but, for instance, by a healing fracture or an inflammation of a different type [ 133 ].…”

Freely Available, Fully Automated AI-Based Analysis of Primary Tumour and Metastases of Prostate Cancer in Whole-Body [18F]-PSMA-1007 PET-CT

“…PSMA is a transmembrane protein that is significantly overexpressed in malignant prostate tissue [ 2 ]. The method is more sensitive and accurate than the conventional imaging standard of CT and bone scan [ 3 , 4 , 5 , 6 , 7 , 8 ]. Different PSMA radiopharmaceuticals exist, such as, for example, [ 68 Ga]PSMA-11 and [ 18 F]PSMA-1007 [ 7 , 9 ].…”