With a new imaging agent in PET/CT test, prostate cancer cells can be detected more precisely compared to all other known techniques.
The fact that the currently available imaging techniques remain inadequate in prostate cancers complicates the estimation of the metastasis of the disease; and consequently, makes it difficult to provide a successful treatment. Standard imaging methods such as computed tomography, magnetic resonance imaging, and bone scan remain inadequate to show prostate cancer metastases.
Even standard FDG PET/CT, considered as the best imaging technique today in the field of cancer, is not ideal in the evaluation of prostate cancer.
PSMA-PET is a targeted molecular imaging technique that utilizes a protein called Prostate-Specific Membrane Antigen (PSMA) on prostate cancer cells, and to detect and monitor that protein. The antibody binds to the PSMA, while Gallium-68 bound to the antibody allows for imaging the prostate cancer cells through the PET scanner. In this way, prostate cancer cells that has spread to the body can be much better detected.
Tumor specific
Prostate specific membrane an
gen is a cell surface protein over-expressed in prostate cancer cells compared to benign prostac
ssue. 68Ga-PSMA detects presence of prostate cancer cells directly, rather than indirect
indicators of disease such as increased bone turnover (bone scan) or enlarged lymph node.
One-stop shop imaging
PSMA PET-CT can be used to image and characterize the primary tumor itself, lymph nodes (independent of size), distal visceral metastases and the bone metastases, all in 1 single scan.
Tumor specific
Prostate specific membrane antigen is a cell surface protein over-expressed in prostate cancer cells compared to benign prostatic tissue. 68Ga-PSMA detects presence of prostate cancer cells directly, rather than indirect indicators of disease such as increased bone turnover (bone scan) or enlarged lymph node.
One-stop shop imaging
PSMA PET-CT can be used to image and characterize the primary tumor itself, lymph nodes (independent of size), distal visceral metastases and the bone metastases, all in 1 single scan.
High sensitivity and specificity
Superior tumour to background contrast compared to other molecular tracers allows for detection of disease in small regional nodes and distant disease in bones or visceral organs.
Early detection of site of recurrence in patients with low level PSA rise who have had definitive therapy Concurrent diagnostic contrast enhanced CT scan of the chest, abdomen and pelvis allows anatomical correlation to foci of abnormal PSMA uptake, significantly increasing sensitivity and specificity of the examination.
Comparable cost
Similar cost to patients when compared with combined 18F-NaF or 99M-TC MDP bone scan and diagnostic CT of the chest, abdomen and pelvis together.
Potential therapy in CRPC
Lutetium-177-labeled anti-prostate-specific membrane antigen monoclonal antibody for metastatic, castration resistant prostate cancer, is also available for suitable patients.
Clinical USES of 68Ga-PSMA PET/CT
– Primary staging in intermediate or high-risk disease according to D’Amico classification
– Biochemical recurrence with low PSA-values (as low as 0.2 ng/ml)
– Biopsy targeting aGer previous negative biopsy, but high suspicion of prostate cancer
– Monitoring of systemic treatment in metastatic castrate-resistant prostate cancer
– Active surveillance
– Treatment monitoring in metastatic castration- resistant prostate cancer undergoing radioligand therapy targeting PSMA(e.g. 177Lu-PSMA-ligand)
PET-MRI imaging for prOState cancer
It is now possible to combine the strengths of both modalities into one single study by doing a Prostate PET-CT with co-registered MRI.
While MRI would give superior resolution in characterising the tumor, the PET imaging would be the most sensitive for metastatic survey including the nodal, visceral and osseous disease.
RADIOLIGAND THERAPIES IN METASTATIC PROSTATE CANCERS (INCLUDING LUTETIUM-PSMA THERAPY AND ALPHA THERAPIES WITH ACTINIUM):
Currently administered in cases with metastatic castrate-resistant prostate cancer, it has demonstrated a significant response. Even in progressive disease at onset, resistant to all conventional therapies, there is a documented response in 60% patients with an achievable median progression-free survival of 11-16 months
OTHER NUCLEAR MEDICINE PROCEDURES OR UROLOGY:
· FDG PET-CT for non-prostatic urologic malignancies
· Renogram (Tc-DTPA / Tc-MAG3) for evaluation of differential and absolute renal function and drainage
· Renal cortical scintigraphy (Tc-DMSA) for evaluation of renal cortical infection
· Direct / indirect VU reflux studies