Nuclear medicine: labelled red cell bleeding scan: 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: labelled red cell bleeding scan

Sample item

A man has intermittent lower gastrointestinal bleeding, with a negative colonoscopy and no source found. Which scan can detect slow or intermittent bleeding over several hours?

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

The answer and the reasoning

A. Technetium-99m labelled red blood cell scan

Labelled red cells remain in the circulation and can be imaged repeatedly for many hours, detecting bleeding as small as 0.1 ml/min and showing its site as tracer pools and moves in the bowel.

Option by option

  • A. Technetium-99m labelled red blood cell scan (correct)

    Correct. The tracer stays intravascular and reveals intermittent bleeding.

  • B. Gallium-67 citrate scan

    Gallium localises inflammation and tumour.

  • C. Technetium-99m sulphur colloid thyroid uptake scan

    A thyroid uptake study is irrelevant to bowel bleeding.

  • D. Fluorine-18 sodium fluoride scan

    Fluoride is a bone-seeking tracer.

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.

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Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is A, Technetium-99m labelled red blood cell scan. Labelled red cells remain in the circulation and can be imaged repeatedly for many hours, detecting bleeding as small as 0.

Why is "Gallium-67 citrate scan" not the answer?

Gallium localises inflammation and tumour.

Why is "Technetium-99m sulphur colloid thyroid uptake scan" not the answer?

A thyroid uptake study is irrelevant to bowel bleeding.

Why is "Fluorine-18 sodium fluoride scan" not the answer?

Fluoride is a bone-seeking tracer.

What concept does this question test?

It tests Nuclear medicine: labelled red cell bleeding scan in Radiology. 1 ml/min and showing its site as tracer pools and moves in the bowel.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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: labelled red cell bleeding scan?

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.