Radiation safety and radiobiology: tissue weighting: 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 · Radiation safety and radiobiology: tissue weighting

Sample item

Two workers each receive the same equivalent dose, one only to the hands and the other to the trunk including stomach, colon, lung and red marrow. Which statement about stochastic risk is correct?

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

The answer and the reasoning

D. The trunk exposure carries the greater effective dose because those organs have higher tissue weighting factors

Effective dose is the sum of organ equivalent doses multiplied by tissue weighting factors, which reflect each organ's sensitivity to cancer and hereditary effects. Marrow, colon, lung and stomach carry high weights, whereas skin and bone surface carry low ones. Equal absorbed dose therefore does not mean equal risk.

Option by option

  • A. The hand exposure is greater because hands receive more scatter

    Scatter does not make hand exposure more hazardous in this sense.

  • B. Effective dose cannot be compared between body regions

    Effective dose was devised precisely to allow such comparisons.

  • C. Both carry identical effective dose because the equivalent dose is the same

    Equal equivalent dose does not give equal effective dose when organs differ in weighting.

  • D. The trunk exposure carries the greater effective dose because those organs have higher tissue weighting factors (correct)

    Correct. Higher weighting factors for trunk organs raise the effective dose.

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, The trunk exposure carries the greater effective dose because those organs have higher tissue weighting factors. Effective dose is the sum of organ equivalent doses multiplied by tissue weighting factors, which reflect each organ's sensitivity to cancer and hereditary effects.

Why is "The hand exposure is greater because hands receive more scatter" not the answer?

Scatter does not make hand exposure more hazardous in this sense.

Why is "Effective dose cannot be compared between body regions" not the answer?

Effective dose was devised precisely to allow such comparisons.

Why is "Both carry identical effective dose because the equivalent dose is th…" not the answer?

Equal equivalent dose does not give equal effective dose when organs differ in weighting.

What concept does this question test?

It tests Radiation safety and radiobiology: tissue weighting in Radiology. Marrow, colon, lung and stomach carry high weights, whereas skin and bone surface carry low ones. Equal absorbed dose therefore does not mean equal risk.

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 Radiation safety and radiobiology: tissue weighting?

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.