How to Read Your PSMA PET Scan: A Patient Guide to Understanding Your Imaging and Your Lu-177 Eligibility

Your Scan Report Arrived. Now You Need Answers.

You received your PSMA PET scan report. Perhaps it arrived as a PDF filled with terms you have never seen: PSMA-avid osseous lesions, SUVmax 8.4, hepatic background activity, retroperitoneal lymphadenopathy. The report feels important — because it is. But without context, it reads like a foreign language.

You are not alone. Most patients who receive a PSMA PET scan report have never learned how to interpret one. The terms are specialized, the implications feel huge, and the link between your scan result and whether you may qualify for Lu-177 PSMA therapy is rarely explained in plain language.

This guide explains what the key terms in your report mean, how nuclear medicine specialists read these scans to assess Lu-177 PSMA eligibility, and what you should do next.

What a PSMA PET Scan Is — and Why It Is Different from Other Scans

PSMA stands for Prostate-Specific Membrane Antigen. It is a protein found on the surface of prostate cancer cells. According to the Society of Nuclear Medicine and Molecular Imaging (SNMMI), prostate cancer cells can express up to 1,000 times more PSMA than normal prostate tissue. This makes PSMA a good target for both imaging and treatment.

During a PSMA PET scan, a small amount of a radioactive tracer — most commonly gallium-68 (Ga-68) PSMA-11 or 18F-DCFPyL — is injected into your bloodstream. This tracer finds cells with high PSMA expression. Wherever those cells exist in your body, the tracer accumulates and sends a signal the PET scanner detects. Cancer deposits show up as bright spots on the image.

The Mayo Clinic notes that PSMA PET scans are far more sensitive than older imaging like bone scans or CT scans. They often detect cancer deposits that older tests would miss entirely. The scan covers your entire body from head to toe, which matters because metastatic prostate cancer can spread to lymph nodes, bones, the liver, and other areas that older tests may not show.

Reading Your Report: A Plain-English Glossary

The narrative section of your PSMA PET scan report may contain some or all of the following terms. Here is what each one means in plain language:

• PSMA-avid: A lesion or area that is actively absorbing the PSMA tracer. This is the same as PSMA-positive — the key finding your oncologist is looking for.
• SUVmax (Standardized Uptake Value, maximum): A number that measures how intensely a spot absorbs the tracer relative to surrounding tissue. Higher values generally mean greater PSMA expression. Doctors compare a lesion's SUVmax to a reference organ — usually the liver — to determine whether it counts as PSMA-positive.
• Hepatic background / liver uptake: The liver naturally absorbs some tracer. It is used as a standard reference point. A lesion with uptake above the liver's level is considered PSMA-positive. One with uptake at or below liver level is considered PSMA-negative for that deposit.
• Osseous lesions / osseous metastases: Cancer that has spread to bone. These show up as bright spots in the spine, pelvis, ribs, femur, or skull on a PSMA PET scan.
• Nodal involvement / lymphadenopathy: Cancer in lymph nodes. Your report will name the location — pelvic, retroperitoneal, mediastinal, or supraclavicular — and note whether those nodes are PSMA-avid.
• Soft tissue lesions: Cancer deposits in organs such as the liver, lung, or adrenal glands. These are separate from lymph nodes and bone metastases.
• PSMA-negative / discordant lesion: A lesion visible on CT or another scan but with little or no PSMA tracer uptake. This is an important finding that can affect your eligibility for Lu-177 PSMA therapy.
• Impression: The radiologist's concluding paragraph — the summary of all findings in plain terms. If you read only one section of a long report, read this one first.

What a PSMA-Positive Result Means for Your Treatment Options

A PSMA-positive result is more than just a label. It tells your oncology team something specific about your cancer: your cancer cells produce the PSMA protein at levels that can be detected and targeted by a therapy designed to find that exact protein.

Lu-177 PSMA therapy works by attaching lutetium-177, a radioactive material, to a molecule that binds to PSMA. When injected, it travels through your bloodstream, finds PSMA-expressing cancer cells wherever they are, attaches to them, and delivers a targeted dose of radiation from inside. Areas with high PSMA expression receive the greatest radiation dose. Nearby healthy tissue receives much less.

This is why a PSMA-positive scan is necessary to qualify for Lu-177 PSMA therapy. Without confirmed PSMA expression on your tumors, the treatment cannot reliably tell cancer cells from healthy tissue. Your scan result determines whether you can access this treatment — which is why understanding exactly what your report says matters so much as you decide what to do next.

How Doctors Use Your Scan to Assess Lu-177 PSMA Eligibility

A positive PSMA PET scan does not automatically mean you qualify for Lu-177 PSMA therapy. Eligibility depends on how your scan is read, based on criteria developed in the VISION clinical trial — the major study that led to FDA approval of lutetium-177 PSMA-617 (Pluvicto) in March 2022.

The VISION eligibility criteria have two parts:

• Positive criterion — at least one PSMA-positive lesion: The scan must show at least one lesion where PSMA uptake is greater than liver uptake. This confirms that your cancer is producing PSMA at a level strong enough for Lu-177 to target effectively.
• Negative criterion — no measurable PSMA-negative lesions: This is the more complex part. If your scan shows a measurable lesion — specifically, a lymph node larger than 2.5 cm, a solid organ lesion larger than 1.0 cm, or a bone lesion with a soft tissue component larger than 1.0 cm — that does not show PSMA uptake above liver level, this may mean that part of your cancer has lost PSMA expression. The VISION trial excluded patients with such lesions because those deposits would not respond to Lu-177 PSMA therapy.

A detailed explanation of why these specific size limits were chosen is available in a paper published in the Journal of Nuclear Medicine by the VISION trial investigators. The goal was to find patients whose cancer produced PSMA in most tumors — so the therapy had the best chance of reaching all active cancer sites.

In simple terms: your scan needs to show that cancer is actively producing PSMA, and that large tumors are producing it too.

What to Do If Your Scan Shows Mixed Results

Some patients get scan results that are neither clearly positive nor clearly negative across all lesions. Perhaps most deposits are PSMA-avid, but one larger lymph node shows lower uptake than the liver. This pattern is sometimes called discordant or mixed, and it is one of the most common reasons patients are told they may not qualify for Lu-177 PSMA therapy.

Mixed results do not automatically disqualify you. Several factors influence how a mixed scan is read:

• Lesion size thresholds matter: The VISION exclusion criteria apply only to lesions above specific size cutoffs. Smaller PSMA-negative areas may not trigger exclusion, even if they show low uptake.
• Reader experience matters: Even experienced nuclear medicine doctors sometimes read the same scan differently when applying the VISION criteria. A second specialist opinion on your scan images — particularly from a center with high Lu-177 PSMA caseload — may produce a different eligibility result.
• Timing of the scan matters: If your scan was performed while you were still on a therapy that competes with PSMA tracer binding (such as certain hormonal treatments), a repeat scan after a washout period may show different uptake results.

If you have been told you do not qualify, ask your team which specific criterion was not met. Was it the scan result itself, a PSMA-negative lesion above the size threshold, blood results, or your prior treatment history? Each answer leads to a different conversation about what comes next. See our article What Are My Real Chances of Qualifying for Lu-177 PSMA Therapy If My PSMA PET Scan Shows Mixed Results.

Beyond the Scan: Other Factors That Affect Eligibility

Your PSMA PET scan is the most important piece of evidence in the eligibility assessment. Specialists will also review:

• Treatment history: The original 2022 FDA approval required prior treatment with both an androgen receptor pathway inhibitor (ARPI — such as enzalutamide or abiraterone) and taxane-based chemotherapy. In March 2025, the FDA expanded this approval to patients who have received an ARPI but are considered appropriate to delay chemotherapy, as confirmed by the Prostate Cancer Foundation. This expansion means more patients may now be eligible than before.
• Kidney function: Lu-177 PSMA therapy is processed through the kidneys. Your creatinine level and estimated GFR (eGFR) will be checked before treatment to make sure your kidneys can handle it safely.
• Blood counts: Because lutetium-177 delivers radiation that can temporarily affect bone marrow, adequate white blood cell count, platelet count, and hemoglobin are required at baseline before any cycle begins.
• Overall performance status: Doctors assess general fitness using the ECOG scale. Most programs accept patients with an ECOG score of 0, 1, or 2 — meaning you are mobile and able to carry out some or all of your daily activities independently.

See our guide Am I a Candidate for Lu-177 PSMA Therapy? A Plain-Language Guide to Eligibility for Men with Metastatic Castration-Resistant Prostate Cancer for details on every eligibility factor.

What International Patients Need to Prepare for a Specialist Scan Review

Patients from the UK, United States, Australia, Canada, and other countries regularly seek Lu-177 PSMA therapy in India, where access, wait times, and cost often compare favorably with domestic options. If you are considering this, here is how to prepare your imaging for review by an Indian specialist center:

• Obtain the full written report, including the narrative section and the impression paragraph. Make sure the report lists SUVmax values for individual lesions and names the reference organ used (typically the liver).
• Request your DICOM image files. These are the raw digital scan files. Most nuclear medicine departments can provide them on a USB drive or via a secure download link. DICOM files let a specialist view your images directly instead of just reading the report.
• Include key blood results: Your most recent PSA level, testosterone result, full blood count, and kidney function test (creatinine and eGFR) should come with the scan documents.
• Provide a treatment history summary: A brief written list of the therapies you have received, when you received them, and your response to each helps the review team understand your disease progression at a glance.
• Check how current your scan is: Most programs prefer imaging done within the past three to six months, or since your most recent change in therapy. If your scan is older, ask whether a new one is recommended before submission.

Once your documents are submitted, a specialist team can typically provide an initial eligibility opinion within a few business days. See our guide Planning Your Lu-177 PSMA Treatment Cycle in India: A Medical Preparation and Travel Guide for International Patients.

Submit Your Scan for a Specialist Eligibility Review

If you have a PSMA PET scan report — or are waiting for one — you can submit it to the specialist team at Lutetium-Therapy.com for review at no obligation. The team works with accredited nuclear medicine and oncology programs in India that accept:

• PSMA PET scan reports and DICOM image files
• Ga-68 DOTATATE scan reports
• PET-CT reports
• Histopathology and biopsy reports
• Prior treatment history and therapy records
• Blood results including PSA, full blood count, and kidney function

The review assesses whether your imaging and clinical profile appear to meet current Lu-177 PSMA eligibility criteria, and outlines what your treatment pathway may look like. If your scan does not appear to support eligibility under current criteria, the team will explain why — and what alternatives or next steps may apply in your situation.

When to Talk to Your Doctor

Talk to your oncologist or a nuclear medicine specialist if your PSMA PET scan report has arrived but no one has explained what it means for your next treatment decision. Ask specifically whether the impression section confirms PSMA-avid disease meeting current eligibility criteria, and whether any lesion was identified as PSMA-negative and above the relevant size threshold. If you have been told you do not qualify, ask which specific criterion was not met — the scan pattern, a non-qualifying lesion, blood results, or your prior treatment history. Each answer will guide what comes next.

This article is for general information and is not a substitute for medical advice. Always consult your oncologist or care team about your specific situation.