Gallium-68 Prostate-Specific Membrane Antigen Positron Emission Tomography: A Practical Guide for Radiologists and Clinicians.

Fathima Fijula Palot Manzil,Harleen Kaur,Lajos Szabados

doi:10.7759/cureus.22917

Abstract

Prostate cancer (PCa) is the third most common form of cancer and the most common cancer diagnosis in men in the United States. It is known that prostate-specific membrane antigen (PSMA) is overexpressed in PCa. PSMA is a type II transmembrane glycoprotein expressed in several benign and malignant tissues. In December 2020, FDA approved Gallium-68 (68Ga) PSMA, which is a PSMA-targeted positron emission tomography (PET) imaging agent. Molecular imaging targeting PSMA has shown substantial advancement in PCa imaging. In this article, we discuss the radiopharmaceutical, indications to do PSMA PET, technical aspects of PSMA PET imaging, normal biodistribution of PSMA, other benign and malignant conditions that can take up PSMA, staging of prostate cancer, and how to report PSMA PET.

Highlights

BackgroundProstate-specific membrane antigen (PSMA) is a glutamate carboxypeptidase II metalloproteinase primarily present in prostatic tissues [1]
Immunohistochemical studies show that prostate-specific membrane antigen (PSMA) expression upsurge in hormone-refractory, dedifferentiated, or metastatic prostate cancer (PCa) and may negatively correlate with survival outcomes
A: Axial 68Ga PSMA positron emission tomography (PET)/computed tomography (CT) image through the pelvis shows subcentimeter bilateral inguinal lymph nodes with mild uptake

Summary

Introduction

Prostate-specific membrane antigen (PSMA) is a glutamate carboxypeptidase II metalloproteinase primarily present in prostatic tissues [1]. A: 68Ga PSMA PET/CT axial image shows uptake in the primary prostate cancer (white thin arrow). B: Coronal PSMA PET/CT image through the chest and upper abdomen of the same patient shows intense radiotracer uptake in the mediastinal lymph nodes (white arrows). B: PET/CT axial image shows intense uptake in the metastatic thoracic vertebra lesion (white arrow) in the same patient. B: Axial PET/CT image through the pelvis in the same patient shows tracer uptake in the right common iliac lymph node metastasis (white thin arrow) and multiple bone metastases (white thick arrows). B: Axial PSMA PET/CT image through the neck in the same patient shows focal intense uptake in a calcified right thyroid nodule (white arrow). A: Axial 68Ga PSMA PET/CT image through the pelvis shows subcentimeter bilateral inguinal lymph nodes with mild uptake (white thin arrows). The effective CT dose ranges from 1 to 20 mSv depending on the CT protocol

Conclusions

Disclosures