New Era in molecular Imaging and introducing a new Radiopharmaceutical
- Introduction- F18-PSMA PET CT
18-F-PSMA positron emission tomography/computed tomography (PET/CT) is a non-invasive diagnostic technique to image prostate cancer. PSMA is a transmembrane protein primarily present in all prostatic tissues. Increased PSMA expression is seen in a variety of malignancies, however, most notably in prostate cancer. Nearly all adenocarcinomas of the prostate demonstrate PSMA expression in the majority of primary and metastatic lesions. Recently PSMA-1007, a new PSMA ligand with limited renal elimination, has been introduced. This tracer is labeled with Fluorine-18 and shows promising results in preliminary studies. The prostate-specific membrane antigen (PSMA)-ligands was a major improvement for the diagnosis of biochemical recurrence in patients with prostate cancer, enabling better tumor detection rate compared with standard radiologic imaging procedures.
clinical applications of F18-PSMA
1 .Staging before and during PSMA-directed radiotherapy (mainly in metastatic castration-resistant prostate cancer)
2.Targeted biopsy after previous negative biopsy in patients with high suspicion of prostate cancer
Accuracy of PSMA-PET scans
- Monitoring of systemic treatment in metastatic prostate cancer
The PSMA-PET scan was 92% accurate in detecting metastatic tumours (or the lack thereof), compared to only 65% accuracy for CT and bone scans.
Accuracy relies on two measures, specificity and sensitivity:
PSMA-PET scans are therefore more accurate for finding or ruling out metastatic tumours at the time of diagnosis than CT and bone scans, for men with high-risk prostate cancer.
- Specificityis the ability to correctly identify those without metastatic tumours (true negative rate). PSMA-PET identified 98% of men correctly who had no metastatic tumours. This was significantly higher than the 91% for CT and bone scans.
- Sensitivityis the ability to correctly identify those with metastatic tumours (true positive rate). PSMA-PET scans correctly identified 85% of men with metastatic tumours, compared to only 38% for CT and bone scans.
- Introduction- F18-DOPA PET CT
Dihydroxyphenylalanine (DOPA) is a neutral amino acid that resembles natural L-dopa (dopamine precursor). It enters the catecholamine metabolic pathway of endogenous L-DOPA in the brain and peripheral tissues. It is amenable to labeling with fluorine-18 (18F) for PET imaging and was originally used in patients with Parkinson’s disease to assess the integrity of the striatal dopaminergic system. The recent introduction and use of hybrid PET/CT scanners has contributed significantly to the management of a series of other pathologies including neuroendocrine tumors, brain tumors, and pancreatic cell hyperplasia. These pathologic entities present an increased activity of L-DOPA decarboxylase and therefore demonstrate high uptake of 18F-DOPA.
The main clinical application of imaging with 18F-DOPA PET/CT is for the assessment of the striatum, brain tumors, NETs, and congenital hyperinsulinemic hypoglycemia.
At Our Fortis Cancer therapy centers has this Facility and we are doing both these test in routine bases.
The Author of article is
Dr M.U Siddiqui
Sr. Consultant and Head of Nuclear Medicine and PET –CT Department
(A Unit of International Oncology services Pvt. Ltd.)
Fortis Hospital Noida,B-22 Sector 62
For Appointment: – 9650291899, 01204300222(Ext .1081)