You are using an outdated browser.

For the best experience on our site, please use Google Chrome.

Download Google Chrome

Clinical Significance of Prostate-Specific Membrane Antigen PET/CT

Why is PSMA PET CT important?

Prostate cancer is the most commonly diagnosed malignant tumor in men and is a leading cause of cancer-related death, only second to lung cancer. Imaging detection of prostate cancer in an earlier stage is the key to more effective treatments, even with the intention of a cure. Unfortunately, it’s well known that each of the conventional medical imaging modalities, such as CT (computed tomography), MRI (magnetic resonance imaging), or nuclear medicine bone scan, has a limited value. The most advanced medical oncology imaging technique is PET CT (positron emission tomography combined with CT). Although PET CT using fluorodeoxyglucose (FDG) as a tracer is well-established and widely accepted for its diagnostic value in the detection of many non-prostate cancers, its sensitivity and specificity are suboptimal for most prostate cancers (Figure 1). Thanks to decades of research efforts leading to recent FDA approval of PSMA (prostate-specific membrane antigen) targeted tracers for PET CT imaging of prostate cancer, mainly because of the much-improved sensitivity and accuracy in comparison to each of conventional imaging modalities or combined.

Negative Fluorodeoxyglucose PET CT Despite Abnormal CT
​Figure 1. Negative Fluorodeoxyglucose PET CT Despite Abnormal CT
Figure 1. Positive Prostate-Specific Membrane Antigen (PSMA) PET CT Showing Multiple Bone Metastases

What do we expect from PSMA PET CT?

PSMA is an abbreviation for prostate-specific membrane antigen. Therefore, PSMA-targeted PET tracer has a high specificity for detecting prostate cancers. Additionally, PSMA is highly expressed in most prostate cancers, leading to much-improved sensitivity from PSMA-targeted PET CT. As a result, PSMA PET CT consistently detects early recurrent prostate cancer, small residual disease within the prostate gland, and or small nodal or bone metastasis. Even other imaging studies are falsely negative or inconclusive. Figure 2 is an example of positive PSMA PET CT showing bilateral pelvic small nodal metastases in a patient who also underwent recent MR imaging, which was negative for metastasis. The superior performance of PSMA PET CT often leads to changes in prostate cancer staging, treatment strategies, and prognostic evaluation. The NCCN (National Comprehensive Cancer Network) 2021 guidelines recommend PSMA PET CT to be a “frontal-line imaging tool” for patients with prostate cancer.

Prostate-Specific Membrane Antigen (PSMA) PET CT Showing Bilateral Pelvic Metastases
​​Figure 2. Prostate-Specific Membrane Antigen (PSMA) PET CT Showing Bilateral Pelvic Metastases.​

How is the status of PSMA PET CT at NCPIC?

Northern California PET Imaging Center (NCPIC) is a non-profit medical imaging facility 100% dedicated to PET imaging services. NCPIC is the first imaging center in the Sacramento area to offer PSMA PET CT services as early as October 2021. Since then, our clinical volume of PSMA PET CT has consistently increased, now averaging 1-2 patients per working day. We at NCPIC strive to provide the best PET CT services to our community. The PET CT scans are carefully reviewed and interpreted by board-certified radiologists, and the final reports are signed off on the same day. 

​​Figure 2. MRI Negative For Metastasis.​