Radiation safety and radiobiology: linear no-threshold model: 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: linear no-threshold model

Sample item

A radiation protection officer states that, for the purposes of protection, there is no dose below which the chance of cancer is assumed to be zero. Which model and effect type is this?

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

The answer and the reasoning

A. Linear no-threshold model for stochastic effects

For stochastic effects such as cancer, the protection system assumes probability rises linearly with dose without a threshold. Severity does not depend on dose, and this assumption is why every exposure needs justification and optimisation.

Option by option

  • A. Linear no-threshold model for stochastic effects (correct)

    Correct. Cancer risk is treated as proportional to dose with no safe threshold.

  • B. Threshold model for deterministic effects

    Deterministic effects have a threshold and their severity rises with dose.

  • C. Hormesis model for stochastic effects

    Hormesis suggests that low doses are beneficial, and it is not adopted in radiation protection.

  • D. Linear-quadratic model for acute syndromes

    The linear-quadratic model describes cell survival curves in radiotherapy and not the protection assumption.

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 A, Linear no-threshold model for stochastic effects. For stochastic effects such as cancer, the protection system assumes probability rises linearly with dose without a threshold.

Why is "Threshold model for deterministic effects" not the answer?

Deterministic effects have a threshold and their severity rises with dose.

Why is "Hormesis model for stochastic effects" not the answer?

Hormesis suggests that low doses are beneficial, and it is not adopted in radiation protection.

Why is "Linear-quadratic model for acute syndromes" not the answer?

The linear-quadratic model describes cell survival curves in radiotherapy and not the protection assumption.

What concept does this question test?

It tests Radiation safety and radiobiology: linear no-threshold model in Radiology. Severity does not depend on dose, and this assumption is why every exposure needs justification and optimisation.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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: linear no-threshold model?

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.