Imaging physics: motion unsharpness in a child: 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.

Try it

Radiology · Imaging physics: motion unsharpness in a child

Sample item

A restless 2-year-old has a blurred chest radiograph because of movement. Which change in technique best reduces motion unsharpness?

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

The answer and the reasoning

D. Shorter exposure time with a higher tube current

Blurring from movement falls when exposure time is shortened, with mA raised to keep the total exposure. Immobilisation and coaching also help. A larger focal spot would worsen geometric sharpness.

Option by option

  • A. A smaller field of view only

    Reducing the field of view does not control movement.

  • B. A larger focal spot to improve penetration

    A larger focal spot increases geometric unsharpness.

  • C. Longer exposure time with a lower tube current

    A long exposure allows more movement during the exposure.

  • D. Shorter exposure time with a higher tube current (correct)

    Correct. A short exposure freezes motion.

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.

More Radiology questions

Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is D, Shorter exposure time with a higher tube current. Blurring from movement falls when exposure time is shortened, with mA raised to keep the total exposure.

Why is "A smaller field of view only" not the answer?

Reducing the field of view does not control movement.

Why is "A larger focal spot to improve penetration" not the answer?

A larger focal spot increases geometric unsharpness.

Why is "Longer exposure time with a lower tube current" not the answer?

A long exposure allows more movement during the exposure.

What concept does this question test?

It tests Imaging physics: motion unsharpness in a child in Radiology. Immobilisation and coaching also help. A larger focal spot would worsen geometric sharpness.

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: motion unsharpness in a child?

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.