Imaging modalities and physics: mammography target and kVp: 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 · Imaging modalities and physics: mammography target and kVp

Sample item

Why does a mammography unit use a molybdenum target with a molybdenum filter and a low tube voltage?

AIt yields characteristic low-energy photons that maximise contrast between fat, glandular tissue and tumourBIt removes all scatter without the need for a gridCIt increases beam penetration so dense breasts need less exposureDIt lets the tube run without a cooling system

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

The answer and the reasoning

A. It yields characteristic low-energy photons that maximise contrast between fat, glandular tissue and tumour

Breast tissue has little natural contrast, so low-energy photons of about 17 to 20 keV are used to exploit differences in photoelectric absorption. A molybdenum target and filter provide these characteristic X-rays. Higher energies would flatten the contrast and hide small lesions.

Option by option

A. It yields characteristic low-energy photons that maximise contrast between fat, glandular tissue and tumour (correct)
Correct. Low-energy characteristic radiation maximises soft tissue contrast in the breast.
B. It removes all scatter without the need for a grid
Scatter is still controlled by a grid or collimation and is not removed by the target.
C. It increases beam penetration so dense breasts need less exposure
Penetration is deliberately low, not high, in mammography.
D. It lets the tube run without a cooling system
Cooling is still required and is unrelated to target choice.

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 A, It yields characteristic low-energy photons that maximise contrast between fat, glandular tissue and tumour. Breast tissue has little natural contrast, so low-energy photons of about 17 to 20 keV are used to exploit differences in photoelectric absorption.

Why is "It removes all scatter without the need for a grid" not the answer?

Scatter is still controlled by a grid or collimation and is not removed by the target.

Why is "It increases beam penetration so dense breasts need less exposure" not the answer?

Penetration is deliberately low, not high, in mammography.

Why is "It lets the tube run without a cooling system" not the answer?

Cooling is still required and is unrelated to target choice.

What concept does this question test?

It tests Imaging modalities and physics: mammography target and kVp in Radiology. A molybdenum target and filter provide these characteristic X-rays. Higher energies would flatten the contrast and hide small lesions.

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 Imaging modalities and physics: mammography target and kVp?

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.