PSMA PET Scan — how it works, what it shows.

What is a PSMA PET scan?

PSMA PET has become the reference-standard scan in prostate cancer for three jobs: staging newly diagnosed intermediate-to-high-risk disease before surgery or radiotherapy, finding recurrence when PSA starts rising again after treatment, and selecting patients for PSMA-targeted radioligand therapy such as Lu-177 PSMA. The same PSMA target that lights up on the scan is the target the therapy attacks — the core idea of theranostics, where we “see it, then treat it.”

At Theranostic Physicians, PSMA PET/CT is performed in the Department of Nuclear Medicine at Fortis Memorial Research Institute (FMRI), Sector 44, Gurugram, with image interpretation led by Dr. Ishita B. Sen and Dr. Dharmender Malik.

The scan is only as good as who reads it.

A PSMA PET result depends on two things working together: a good machine to acquire a clean, high-resolution study, and a good reader — an experienced nuclear medicine physician — to interpret it correctly. Two readers looking at the same images on the same scanner can reach different conclusions; in prostate cancer, that interpretation steers the diagnosis, the staging, and whether a patient is offered Lu-PSMA therapy.

• The institution. Scans are performed at Fortis Memorial Research Institute, Sector 44, Gurugram — a leading tertiary hospital with a dedicated Department of Nuclear Medicine and modern PET/CT imaging.
• The reader. Every study is interpreted by Dr. Ishita B. Sen and Dr. Dharmender Malik, whose years of focused theranostics experience are exactly what a borderline or complex PSMA scan needs — distinguishing true disease from the normal PSMA uptake seen in salivary glands, bowel and the urinary tract.

A scan is only ever as reliable as the equipment that acquires it and the physician who reads it. We hold both to the same standard.

How a PSMA PET works.

Most prostate cancers overexpress PSMA on the surface of their cells — with expression tending to rise as the disease becomes more aggressive. A PSMA PET scan exploits that biology in four steps:

• The tracer. A small molecule that binds PSMA with high affinity is labelled with a positron-emitting radionuclide. The most common are Gallium-68 PSMA-11 (the agent used in the proPSMA trial) and the fluorine-18 agents piflufolastat F-18 (PSMA-1007 / DCFPyL). The choice depends on availability and the clinical question.
• Injection. A small intravenous injection delivers the tracer. The amount of the binding molecule is a microdose — far too small to have any pharmacological effect.
• Uptake. Over roughly 50 to 60 minutes the tracer circulates and locks onto PSMA on prostate cancer cells wherever they are — prostate bed, lymph nodes, bone, or soft tissue.
• Imaging. The PET scanner detects the radiation emitted from those sites and builds a three-dimensional map; the CT component adds precise anatomical location. PSMA-avid disease appears as bright “hot spots.”

Some PSMA uptake is normal: the salivary and tear glands, liver, spleen, kidneys, bowel and urinary tract all take up the tracer physiologically. Distinguishing this normal pattern from disease is a core part of expert reporting, and is why interpretation matters as much as the machine.

Who needs a PSMA PET scan?

A PSMA PET scan is recommended in a few well-defined situations. Your urologist or oncologist will usually be the one to request it:

• Staging high-risk prostate cancer. For newly diagnosed intermediate-to-high-risk disease, to check whether cancer has spread to lymph nodes or bone before deciding on surgery or radiotherapy. Accurate staging changes the treatment plan.
• A rising PSA after treatment (biochemical recurrence). When PSA climbs again after surgery or radiotherapy, PSMA PET can pinpoint where the cancer has returned — often while PSA is still low — so treatment can be targeted.
• Selecting and planning radioligand therapy. To confirm a tumour is PSMA-positive before Lu-177 PSMA or Ac-225 PSMA therapy, and to map the disease beforehand.
• Restaging and response assessment. To reassess the extent of disease in advanced prostate cancer, or to see how it is responding.

What to expect on the day.

A PSMA PET scan is an outpatient test. Plan for about two hours at the centre, most of which is the quiet uptake period — the scan itself is short and painless.

Most patients are in and out the same morning. Out-of-town and international patients are helped with scheduling so the scan, review and any onward plan can be arranged in a single short trip.

What a PSMA PET shows — and how it compares.

The reason PSMA PET has changed prostate cancer imaging is simple: it is markedly more accurate than the conventional combination of CT and bone scan, because it images the cancer directly.

• Staging. In the randomised proPSMA trial, PSMA PET/CT was 27% more accurate than CT plus bone scan for staging high-risk prostate cancer (92% versus 65%), with fewer uncertain results and less than half the radiation exposure.
• Recurrence. When PSA rises after treatment, PSMA PET localises the cancer even at low PSA values where conventional imaging is usually blank — finding disease in a meaningful share of patients with PSA below 0.5 ng/mL.
• Impact on decisions. Because it finds disease earlier and maps it more completely, PSMA PET changes the management plan in a substantial proportion of cases — for example, redirecting from local treatment to systemic therapy, or vice versa.

What it does not replace: a multiparametric MRI of the prostate, which remains the test for assessing the prostate gland itself and guiding biopsy. PSMA PET and prostate MRI answer different questions and are often used together. For the wider picture of how molecular PET differs from anatomical scans, see PET scan vs CT scan.

From scan to therapy.

A PSMA PET scan is not only diagnostic — it is the doorway to treatment. This is the heart of theranostics: the very same PSMA receptor that the scan lights up is what a PSMA-targeted therapy binds to and irradiates.

If the scan shows PSMA-positive disease, you may be a candidate for Lu-177 PSMA therapy — the radioligand treatment (brand name Pluvicto) that delivers radiation directly to PSMA-expressing prostate cancer. In selected patients with aggressive or progressing disease, Ac-225 PSMA alpha therapy is the next option. A PSMA-positive scan, read alongside your clinical picture, is what makes that pathway possible.

If you already have PSMA PET images from elsewhere and want an independent expert opinion before deciding, our Second Read service provides a formal re-read of your existing study.

Cost of a PSMA PET scan in India.

The PSMA PET/CT scan is billed by Fortis Memorial Research Institute. The price you pay is the same hospital counter price for everyone — with no commission added for booking and coordinating through our team. We do not discount; the value is in the accuracy of the scan and the physician who reads it, not in the price.

Is a PSMA PET scan safe?

Yes — a PSMA PET scan is a very safe, well-tolerated test. It is non-invasive apart from a single small injection.

Tracer & side effects

• The PSMA tracer is given in a microdose; allergic or adverse reactions are rare and usually mild.
• There is no sedation and none of the contrast-dye reactions associated with iodinated CT contrast.
• You can eat, drink and drive as normal afterwards. Drinking fluids helps flush the tracer, which is cleared mainly through the kidneys.

Radiation

• The radiation dose is low — in the range of other routine diagnostic PET/CT studies, and a small fraction of any therapeutic dose.
• The radioactivity decays quickly. As a routine precaution we may advise limiting prolonged close contact with pregnant women and young children for a few hours after the scan.

Pregnancy & breastfeeding

• Tell the team beforehand if there is any possibility of pregnancy or if you are breastfeeding, so appropriate precautions can be taken. (PSMA PET is a prostate-cancer test and so this applies in specific contexts only.)

Book a PSMA PET scan.

PSMA PET/CT is performed at the Department of Nuclear Medicine, Fortis Memorial Research Institute, Sector 44, Gurugram — the single centre where we deliver scans — with interpretation led by Dr. Ishita B. Sen and Dr. Dharmender Malik. Our team coordinates directly with the department so you skip the phone queues, and can usually secure a priority slot on a best-effort basis.

Already have PSMA PET images from another centre? You can request an independent expert opinion through our Second Read service without travelling.