Radiotherapy and nuclear medicine basics: DTPA and glomerular filtration: 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 · Radiotherapy and nuclear medicine basics: DTPA and glomerular filtration

Sample item

Which renal radiopharmaceutical is cleared almost entirely by glomerular filtration and used to measure glomerular filtration rate?

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

The answer and the reasoning

C. Tc-99m DTPA

Tc-99m DTPA is freely filtered by the glomerulus and not reabsorbed, so its clearance estimates GFR. MAG3 is secreted by the proximal tubule and DMSA binds to the cortex.

Option by option

  • A. Tc-99m DMSA

    DMSA binds to proximal tubular cells and images the renal cortex and scars.

  • B. Tc-99m sulphur colloid

    Sulphur colloid is cleared by the reticuloendothelial system, not by the kidney.

  • C. Tc-99m DTPA (correct)

    Correct. DTPA is eliminated by glomerular filtration, giving a measure of GFR.

  • D. Tc-99m MAG3

    MAG3 is cleared mainly by tubular secretion and is used for renal plasma flow and drainage.

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 C, Tc-99m DTPA. Tc-99m DTPA is freely filtered by the glomerulus and not reabsorbed, so its clearance estimates GFR.

Why is "Tc-99m DMSA" not the answer?

DMSA binds to proximal tubular cells and images the renal cortex and scars.

Why is "Tc-99m sulphur colloid" not the answer?

Sulphur colloid is cleared by the reticuloendothelial system, not by the kidney.

Why is "Tc-99m MAG3" not the answer?

MAG3 is cleared mainly by tubular secretion and is used for renal plasma flow and drainage.

What concept does this question test?

It tests Radiotherapy and nuclear medicine basics: DTPA and glomerular filtration in Radiology. MAG3 is secreted by the proximal tubule and DMSA binds to the cortex.

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 Radiotherapy and nuclear medicine basics: DTPA and glomerular filtration?

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.