Radiation protection: potassium iodide: 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 · Radiation protection: potassium iodide

Sample item

A nuclear plant accident releases radioiodine into the air. Which countermeasure protects the population's thyroid glands?

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

The answer and the reasoning

A. Stable potassium iodide taken before or soon after exposure

Stable iodide saturates the thyroid so that radioactive iodine is not taken up and is excreted in urine. It protects best when given just before or very soon after exposure and children and pregnant women are priority groups.

Option by option

  • A. Stable potassium iodide taken before or soon after exposure (correct)

    Correct. Stable iodide blocks thyroid uptake of radioiodine.

  • B. Prussian blue given orally

    Prussian blue binds caesium and thallium, not iodine.

  • C. Oral activated charcoal

    Charcoal does not prevent thyroid accumulation of absorbed radioiodine.

  • D. Intravenous calcium gluconate

    Calcium gluconate treats hypocalcaemia and does not block iodine uptake.

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, Stable potassium iodide taken before or soon after exposure. Stable iodide saturates the thyroid so that radioactive iodine is not taken up and is excreted in urine.

Why is "Prussian blue given orally" not the answer?

Prussian blue binds caesium and thallium, not iodine.

Why is "Oral activated charcoal" not the answer?

Charcoal does not prevent thyroid accumulation of absorbed radioiodine.

Why is "Intravenous calcium gluconate" not the answer?

Calcium gluconate treats hypocalcaemia and does not block iodine uptake.

What concept does this question test?

It tests Radiation protection: potassium iodide in Radiology. It protects best when given just before or very soon after exposure and children and pregnant women are priority groups.

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 Radiation protection: potassium iodide?

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.