Nuclear medicine: PSMA PET: practice question

A Radiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Radiology · Nuclear medicine: PSMA PET

Sample item

A man has a rising PSA of 0.4 ng/ml after radical prostatectomy and conventional imaging is normal. Which study best localises recurrence at this low level?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Gallium-68 PSMA PET-CT

Prostate-specific membrane antigen is overexpressed in prostate cancer cells, and PSMA ligands labelled with gallium-68 detect small nodal and distant deposits even at low PSA. It is more sensitive than conventional staging at low PSA.

Option by option

  • A. Gallium-68 PSMA PET-CT (correct)

    Correct. PSMA PET is the most sensitive test for biochemical recurrence.

  • B. Plain chest radiograph

    A chest film will not find small deposits.

  • C. Technetium-99m MDP bone scan

    A bone scan is insensitive at very low PSA and misses nodal disease.

  • D. Abdominal ultrasound

    Ultrasound cannot survey for nodal and distant recurrence.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Radiology questions

Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is A, Gallium-68 PSMA PET-CT. Prostate-specific membrane antigen is overexpressed in prostate cancer cells, and PSMA ligands labelled with gallium-68 detect small nodal and distant deposits even at low PSA.

Why is "Plain chest radiograph" not the answer?

A chest film will not find small deposits.

Why is "Technetium-99m MDP bone scan" not the answer?

A bone scan is insensitive at very low PSA and misses nodal disease.

Why is "Abdominal ultrasound" not the answer?

Ultrasound cannot survey for nodal and distant recurrence.

What concept does this question test?

It tests Nuclear medicine: PSMA PET in Radiology. It is more sensitive than conventional staging at low PSA.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Nuclear medicine: PSMA PET?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.