PSMA PET CT uses a special tracer to find prostate cancer spread and recurrence. Learn how it differs from FDG PET CT and when it is advised.
PSMA PET CT is a special scan for prostate cancer that uses a tracer attached to a molecule seeking prostate-specific membrane antigen (PSMA), which is high on prostate cancer cells. It is very sensitive for finding spread to nodes and bones and recurrence after treatment, especially when PSA is rising.
Why Is a Special Tracer Needed?
Many prostate cancers use little glucose, so FDG PET CT can miss them. PSMA is a protein found in large amounts on most prostate cancer cells. The PSMA tracer sticks to these cells and lights them up. This makes PSMA PET CT much better at finding small deposits. See FDG tracer explained for the common tracer.
FeaturePSMA PET CTFDG PET CTTracer targetPSMA protein on prostate cellsGlucose useBest forProstate cancerMany cancers; less sensitive for prostateCommon tracersGa-68 or F-18 labelled PSMAF-18 FDGFastingUsually not requiredRequiredCommon useStaging, recurrence, therapy planningLymphoma, lung, colon and othersWhen Is PSMA PET CT Advised?
- High-risk prostate cancer before treatment, to look for spread
- PSA rising after surgery or radiotherapy (biochemical recurrence)
- Planning radiotherapy or surgery for limited spread
- Selecting patients for PSMA-targeted radioligand therapy
How It Compares With MRI and Bone Scan
Multiparametric MRI is the best test to see the prostate gland itself. A bone scan has been used to look for bone spread, but PSMA PET CT is more sensitive. Many centres now use PSMA PET CT for staging in high-risk disease. Read multiparametric MRI for prostate.
Preparation
- Fasting is usually not required, but follow your centre's advice.
- Drink plenty of water and empty your bladder before the scan.
- Bring your PSA reports, biopsy report, MRI and treatment details.
- Tell the staff about hormone therapy, since it may change uptake.
Limits
PSMA is also present in some normal tissues such as the salivary glands, kidneys and bowel, and in some non-prostate tumours. Very small spots or cancers with low PSMA may be missed. The report must be read by an experienced nuclear medicine physician with your history. Radiation doses are similar to other PET CT scans. See PET CT radiation and safety.
A Practical Example
Dinesh, 66, had prostate surgery two years ago. His PSA rises from 0.1 to 0.8 ng/mL, but CT and bone scan are normal. A PSMA PET CT shows a single active pelvic node. His doctors plan targeted radiotherapy instead of long-term systemic therapy. Without the scan, the site of recurrence would have remained unknown.
Quick Summary
- PSMA PET CT is highly sensitive for prostate cancer
- It is used in staging and rising PSA
- Fasting is not usually needed
- It supports targeted treatment decisions
Questions to Ask Your Doctor
- Is my PSA level right for a PSMA scan?
- Will the scan change my treatment plan?
- Should hormone therapy be paused?
- Which tracer does the centre use?
Common Mistakes to Avoid
- Forgetting to bring PSA and biopsy reports.
- Not emptying the bladder before the scan.
- Assuming a normal PSMA scan means no cancer anywhere.
Booking, Timing and Report
Ask your doctor for the best timing of the scan. Book a morning slot so that fasting is easier, arrange someone to accompany you, and allow 2 to 3 hours at the centre. Carry biopsy, scan and blood reports and a medicine list. Reports are usually ready within 24 to 48 hours, and images can be given on a CD or digital link for your doctor.
Key Facts at a Glance
- PSMA PET CT targets prostate cancer cells directly
- It is more sensitive than FDG PET CT for prostate cancer
- It guides treatment in rising PSA and high-risk disease
- Drink water and empty your bladder before the scan
Ask your urologist or oncologist whether PSMA PET CT will change your management before you book. Plan the date so that it falls at a suitable point in your treatment schedule.
Frequently Asked Questions
What is PSMA PET CT?
A PET CT scan using a tracer that targets PSMA on prostate cancer cells.
Is it better than a bone scan?
It is generally more sensitive.
Do I need fasting?
Usually not, but follow your centre.
When is it done after surgery?
When PSA starts rising, as advised by your urologist.
Does it replace biopsy?
No.
Can hormone therapy affect results?
Yes. Tell the team about hormone treatment.
Is it safe?
Yes, the radiation dose is similar to other PET CT scans.
Can I have it with a normal MRI?
Yes. MRI shows the gland; PSMA shows spread.
How long does it take?
About 2 to 3 hours in total.
Book Your Test at Ganesh Diagnostic
Ganesh Diagnostic & Imaging Centre in Rohini, Delhi offers this test with trained radiology staff and clear reports. You can book an appointment online, check our branches across Delhi NCR, contact us for current rates, or explore all our services. Reports can be downloaded online through our patient portal, so you do not need to make a second trip just to collect them.
This article is for general information only. It does not replace advice from your doctor. Always follow your doctor's instructions for your test.
Related Reading
- PET CT Scan for Head and Neck Cancer
- PET CT Scan for Cervical and Ovarian Cancer
- PET CT Scan for Colorectal Cancer: Uses & Benefits
- PET CT Brain Scan for Dementia and Epilepsy
- PET CT Scan for Lymphoma: Staging and Follow-Up
- MRI Abdomen Scan: Uses and Preparation
- Coronary Plaque Types Seen on CT Angiography
