PSMA PET/CT Scan - Prostate Cancer Imaging
A PSMA PET/CT scan uses a tracer that binds to prostate cancer cells to show spread anywhere in the body, with far greater accuracy than CT and bone scan. It stages high-risk prostate cancer, locates recurrence when PSA rises after surgery or radiotherapy, and selects patients for PSMA radioligand therapy. The scan takes about two hours, the report follows within two working days, and you can fly home the same day.
About This Department
A PSMA PET/CT scan finds prostate cancer cells that CT and bone scans miss. What it shows can change the treatment plan.
A PSMA PET/CT scan is a nuclear medicine test for prostate cancer. A small amount of a radioactive tracer that binds to PSMA, prostate-specific membrane antigen, a protein found in large amounts on prostate cancer cells, is injected into a vein, and a PET/CT scanner maps where it collects throughout the body. It is used to stage high-risk prostate cancer before surgery or radiotherapy, to find the source of a rising PSA after treatment, and to select patients for PSMA radioligand therapy. In a randomized trial of 302 men with high-risk prostate cancer, PSMA PET/CT was 92 percent accurate in detecting spread to lymph nodes or distant sites, against 65 percent for CT and bone scan combined, with less than half the radiation dose (Hofman and colleagues, Lancet, 2020). This page explains how the scan works, who needs one, results in staging and in recurrence, its role before radioligand therapy, preparation and the scan day, reading the report, safety, and how patients from abroad arrange a scan at Biruni Hospital in Istanbul.
What a PSMA PET/CT scan is
| Scan | What it shows | Limitation |
|---|---|---|
| CT scan | Enlarged lymph nodes, organ spread | Misses cancer in normal-sized nodes |
| Bone scan | Bone reaction to cancer | Misses small deposits, confused by arthritis |
| Prostate MRI | Cancer inside the prostate and nearby | Covers only the pelvis |
| PSMA PET/CT | Cancer cells anywhere in the body, down to a few millimeters | Some prostate cancers make little PSMA |
PSMA sits on the surface of most prostate cancer cells at levels hundreds of times higher than in normal tissue. The tracer seeks it out wherever the cancer has gone.
| Tracer | Label | Note |
|---|---|---|
| Ga-68 PSMA-11 | Gallium-68 | The most studied, used in the main trials |
| F-18 PSMA-1007, piflufolastat and others | Fluorine-18 | Longer half-life, sharp images, less bladder activity with some agents |
Who needs one
| Situation | Question answered | Effect on treatment |
|---|---|---|
| High-risk or unfavorable intermediate-risk cancer at diagnosis | Has it spread beyond the prostate | Surgery or radiotherapy planned correctly, or systemic treatment |
| Rising PSA after prostatectomy or radiotherapy | Where is the cancer coming back | Targeted salvage radiotherapy or surgery |
| Advanced cancer before radioligand therapy | Do the tumors carry enough PSMA | Eligibility for lutetium-177 PSMA |
| Suspicious findings on other scans | Is this prostate cancer | Avoids wrong treatment |
Not a screening test
Staging high-risk cancer
The proPSMA trial
PSMA PET-CT had a 27 percent greater accuracy than that of conventional imaging, 92 percent against 65 percent, and conventional imaging had more equivocal findings, 23 percent against 7 percent (Hofman and colleagues, Lancet, 2020).
| Measure | CT and bone scan | PSMA PET/CT |
|---|---|---|
| Accuracy | 65 percent | 92 percent |
| Sensitivity | 38 percent | 85 percent |
| Management changed by first scan | 15 percent | 28 percent |
| Radiation dose | 19.2 millisieverts | 8.4 millisieverts |
Rising PSA after treatment
| PSA before scan, ng/mL | Scans showing cancer | Note |
|---|---|---|
| Below 0.5 | 38 percent | Still worth scanning when salvage treatment is planned |
| 0.5 to under 1.0 | 57 percent | Good balance of detection and curability |
| 1.0 to under 2.0 | 84 percent | High detection |
| 5.0 or above | 97 percent | Nearly always positive |
For PSA categories 0 to 0.19, 0.2 to 0.49, 0.5 to 0.99, 1 to 1.99 and 2 or more ng/mL, the percentages of positive scans were 33, 45, 59, 75 and 95 percent (Perera and colleagues, European Urology, 2020).
Before PSMA radioligand therapy
Lutetium-177-PSMA-617 plus standard care prolonged overall survival to a median of 15.3 months against 11.3 months with standard care alone in PSMA-positive metastatic castration-resistant prostate cancer (Sartor and colleagues, New England Journal of Medicine, 2021).
Selecting patients
Monitoring
Repeat scans during and after radioligand therapy show how the disease responds.
Preparing for the scan
A recent PSA result, within the last four weeks, helps interpret the scan.
| Item | Why | Note |
|---|---|---|
| PSA history with dates | Interpreting the result | Shows the trend |
| Earlier scans on disc | Comparison | MRI, CT, bone scan, earlier PET |
| List of medicines | Hormone therapy affects uptake | Include start dates |
| Comfortable clothes without metal | Avoids artifacts | A gown can be provided |
Scan day
Timeline
| Step | Time | Note |
|---|---|---|
| Arrival and check-in | 15 minutes | Weight, PSA and history reviewed |
| Injection and rest | About 60 minutes | Quiet room, drink water |
| Scan | 20 to 30 minutes | Lie still, breathe normally |
| Leave | Right after | Normal activity |
After the scan
Drink water and empty your bladder every hour or two for the rest of the day to clear the tracer. Eat, drive and work as usual.
Reading the report
| Term | Meaning | Why it matters |
|---|---|---|
| SUVmax | Intensity of tracer uptake | Higher values point to more PSMA-rich cancer |
| PSMA-RADS or PROMISE score | Standard scale of how likely a finding is cancer | Helps decide whether to act on it |
| miTNM | Staging based on molecular imaging | Local, nodal and distant disease |
Can the scan show something that is not cancer?
What a negative scan means
A clear scan is good news, with a caveat.
The scanner cannot see deposits smaller than a few millimeters, and up to one in ten prostate cancers make little PSMA. After prostatectomy, a negative scan with a low but rising PSA still supports early salvage radiotherapy to the prostate bed, since microscopic cancer there is the likeliest source. The PSA trend over time remains the guide.
Repeat the scan later if PSA keeps rising. Detection climbs with every doubling of PSA, and a scan that was negative at 0.3 may show a single treatable lymph node at 0.8, still early enough for targeted radiotherapy with a real chance of long-term control.
Timing matters more than anything.
Safety
The radiation dose from PSMA PET/CT, about 8 millisieverts, is less than half that of a CT and bone scan combined and similar to a few years of natural background radiation.
- Allergic reactions to the tracer are extremely rare.
- The tracer does not affect kidney function or blood sugar.
- The CT part is done without contrast in most cases, or with contrast if requested for diagnosis.
No special precautions are needed after you leave the department, apart from drinking water and emptying the bladder often.
Contact with young children and pregnant women
Avoid holding babies or sitting close to pregnant women for the rest of the scan day. No other steps apply.
For patients from abroad
Length of stay
One coordinator from the international patients office handles arrangements from the first message through discharge and answers the same WhatsApp number once you are back home. The office works in English, Arabic, French, Russian, Serbian, Romanian and Spanish and books interpreters for other languages, and it arranges the visa invitation letter, airport transfers, daily transport and accommodation near the hospital. Halal, vegetarian and diabetic meals, a prayer room on site, and a female physician on request wherever the rota allows.
Cost
| Item | Included | Priced separately |
|---|---|---|
| The scan | Tracer, PET/CT imaging, report | Additional MRI or biopsy |
| Consultation | Nuclear medicine review of the result | Urology or oncology treatment consultation |
| Copies | Images on disc and electronic report | Translation of the report into another language |
Comparing quotes
Insurance
Many international insurers cover PSMA PET/CT for guideline indications. The coordinator can provide a quote and a medical justification letter in advance.
References
- Hofman MS, Lawrentschuk N, Francis RJ, et al. Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy (proPSMA). A prospective, randomised, multicentre study. Lancet. 2020;395(10231):1208-1216.
- Fendler WP, Calais J, Eiber M, et al. Assessment of 68Ga-PSMA-11 PET accuracy in localizing recurrent prostate cancer. A prospective single-arm clinical trial. JAMA Oncol. 2019;5(6):856-863.
- Perera M, Papa N, Roberts M, et al. Gallium-68 prostate-specific membrane antigen positron emission tomography in advanced prostate cancer. Updated diagnostic utility, sensitivity, specificity, and distribution of prostate-specific membrane antigen-avid lesions. A systematic review and meta-analysis. Eur Urol. 2020;77(4):403-417.
- Sartor O, de Bono J, Chi KN, et al. Lutetium-177-PSMA-617 for metastatic castration-resistant prostate cancer. N Engl J Med. 2021;385(12):1091-1103.
Editor's note
Written by the Biruni Hospital medical editorial team. Reviewed by Specialist Dr. Nesrin Aslan İlkmen, Nuclear Medicine.
Medically reviewed by
Specialist Dr. Nesrin Aslan İlkmen
Nuclear Medicine
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