Radiotherapy: IMRT: 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: IMRT

Sample item

A head and neck cancer patient is planned for intensity-modulated radiotherapy rather than parallel opposed fields. What is the main benefit sought?

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

The answer and the reasoning

D. Conforming dose to a concave target while sparing the parotid glands and spinal cord

IMRT varies beam intensity across each field, usually with a multileaf collimator, so high dose wraps around a concave target. This reduces xerostomia and cord dose compared with simple fields.

Option by option

  • A. Using radioactive seeds placed inside the tumour

    Seeds placed in the tumour define brachytherapy.

  • B. Replacing the need for treatment planning CT

    IMRT relies on detailed CT-based planning.

  • C. Delivering the whole dose in a single fraction

    Single-fraction treatment is characteristic of radiosurgery, not routine IMRT.

  • D. Conforming dose to a concave target while sparing the parotid glands and spinal cord (correct)

    Correct. Modulated beams give conformal dose and sparing of nearby organs.

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, Conforming dose to a concave target while sparing the parotid glands and spinal cord. IMRT varies beam intensity across each field, usually with a multileaf collimator, so high dose wraps around a concave target.

Why is "Using radioactive seeds placed inside the tumour" not the answer?

Seeds placed in the tumour define brachytherapy.

Why is "Replacing the need for treatment planning CT" not the answer?

IMRT relies on detailed CT-based planning.

Why is "Delivering the whole dose in a single fraction" not the answer?

Single-fraction treatment is characteristic of radiosurgery, not routine IMRT.

What concept does this question test?

It tests Radiotherapy: IMRT in Radiology. This reduces xerostomia and cord dose compared with simple fields.

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: IMRT?

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.