Radiotherapy: brachytherapy: 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: brachytherapy

Sample item

In carcinoma cervix, intracavitary brachytherapy is advantageous mainly because of which property?

AA uniform dose to the whole pelvis including nodesBElimination of the need for external beam therapyCSteep dose fall-off sparing adjacent bladder and rectumDUse of low-energy electrons only

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

The answer and the reasoning

C. Steep dose fall-off sparing adjacent bladder and rectum

Brachytherapy places the source within or near the tumour, and the dose falls according to the inverse square law, delivering a high dose to the cervix and parametrium while sparing normal tissues. It is combined with external beam therapy and chemotherapy. Nodal sites are treated by the external beam.

Option by option

A. A uniform dose to the whole pelvis including nodes
Brachytherapy does not give uniform coverage to nodes.
B. Elimination of the need for external beam therapy
It complements, and does not replace, external beam therapy.
C. Steep dose fall-off sparing adjacent bladder and rectum (correct)
Correct. Rapid dose fall-off protects bladder and rectum.
D. Use of low-energy electrons only
The sources are gamma emitters such as Ir-192.

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.

Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is C, Steep dose fall-off sparing adjacent bladder and rectum. Brachytherapy places the source within or near the tumour, and the dose falls according to the inverse square law, delivering a high dose to the cervix and parametrium while sparing normal tissues.

Why is "A uniform dose to the whole pelvis including nodes" not the answer?

Brachytherapy does not give uniform coverage to nodes.

Why is "Elimination of the need for external beam therapy" not the answer?

It complements, and does not replace, external beam therapy.

Why is "Use of low-energy electrons only" not the answer?

The sources are gamma emitters such as Ir-192.

What concept does this question test?

It tests Radiotherapy: brachytherapy in Radiology. It is combined with external beam therapy and chemotherapy. Nodal sites are treated by the external beam.

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: brachytherapy?

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.