Nuclear medicine: preparation for radioiodine ablation: 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: preparation for radioiodine ablation

Sample item

A patient after total thyroidectomy for papillary carcinoma is booked for radioiodine remnant ablation. Which preparation increases remnant uptake?

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

The answer and the reasoning

D. A raised TSH, by thyroid hormone withdrawal or recombinant TSH, along with a low-iodine diet

Thyroid cells take up iodide under TSH stimulation, so TSH must be high and body iodine stores low. This is achieved by withdrawing levothyroxine or giving recombinant TSH and keeping to a low-iodine diet. Iodine loads from contrast or supplements dilute the radioiodine.

Option by option

  • A. High-dose potassium iodide the day before

    A potassium iodide load blocks radioiodine uptake.

  • B. Intravenous iodinated contrast one week before

    Iodinated contrast suppresses uptake for weeks.

  • C. Continued levothyroxine with a high-iodine diet

    A high-iodine diet competes with the therapy dose.

  • D. A raised TSH, by thyroid hormone withdrawal or recombinant TSH, along with a low-iodine diet (correct)

    Correct. High TSH and low iodine stores raise 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 D, A raised TSH, by thyroid hormone withdrawal or recombinant TSH, along with a low-iodine diet. Thyroid cells take up iodide under TSH stimulation, so TSH must be high and body iodine stores low.

Why is "High-dose potassium iodide the day before" not the answer?

A potassium iodide load blocks radioiodine uptake.

Why is "Intravenous iodinated contrast one week before" not the answer?

Iodinated contrast suppresses uptake for weeks.

Why is "Continued levothyroxine with a high-iodine diet" not the answer?

A high-iodine diet competes with the therapy dose.

What concept does this question test?

It tests Nuclear medicine: preparation for radioiodine ablation in Radiology. This is achieved by withdrawing levothyroxine or giving recombinant TSH and keeping to a low-iodine diet. Iodine loads from contrast or supplements dilute the radioiodine.

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: preparation for radioiodine ablation?

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.