Imaging physics: scatter control in a lumbar radiograph: 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 physics: scatter control in a lumbar radiograph

Sample item

A lateral lumbar spine radiograph in a large patient looks grey and low in contrast. Which two measures most directly improve it by reducing scattered radiation?

ATighter collimation and use of an anti-scatter gridBRemove the filtration from the beamCIncrease the film-focus distance to infinityDLower the tube current and shorten the exposure only

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

The answer and the reasoning

A. Tighter collimation and use of an anti-scatter grid

Scatter from a thick body part fogs the image and lowers contrast. Collimating to the area of interest cuts the irradiated volume, and a grid absorbs scattered photons before they reach the detector. Both approaches also reduce unnecessary exposure.

Option by option

A. Tighter collimation and use of an anti-scatter grid (correct)
Correct. Collimation and a grid reduce scatter reaching the detector.
B. Remove the filtration from the beam
Filtration removes low-energy photons and its removal would add dose without helping contrast.
C. Increase the film-focus distance to infinity
Distance has little effect on scatter produced inside the patient.
D. Lower the tube current and shorten the exposure only
Changing mA and time alters density but does not remove scatter.

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, Tighter collimation and use of an anti-scatter grid. Scatter from a thick body part fogs the image and lowers contrast.

Why is "Remove the filtration from the beam" not the answer?

Filtration removes low-energy photons and its removal would add dose without helping contrast.

Why is "Increase the film-focus distance to infinity" not the answer?

Distance has little effect on scatter produced inside the patient.

Why is "Lower the tube current and shorten the exposure only" not the answer?

Changing mA and time alters density but does not remove scatter.

What concept does this question test?

It tests Imaging physics: scatter control in a lumbar radiograph in Radiology. Collimating to the area of interest cuts the irradiated volume, and a grid absorbs scattered photons before they reach the detector. Both approaches also reduce unnecessary exposure.

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 physics: scatter control in a lumbar radiograph?

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.