Radiation effects: fetal exposure: 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 effects: fetal exposure

Sample item

At which period of gestation is the risk of major malformations from radiation greatest?

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

The answer and the reasoning

C. Organogenesis (about weeks 2 to 8 after conception)

Malformations are chiefly caused during organogenesis, and CNS effects are important during 8 to 15 weeks. Pre-implantation exposure follows an all-or-none pattern, with death or normal development. Deterministic fetal effects are not expected below about 100 mGy.

Option by option

  • A. Immediately before delivery

    Delivery is too late for structural malformation.

  • B. Pre-implantation (first 10 days)

    Pre-implantation shows an all-or-none effect.

  • C. Organogenesis (about weeks 2 to 8 after conception) (correct)

    Correct. Organogenesis is the highest-risk period for malformations.

  • D. Third trimester

    Third trimester carries less risk of malformation, though cancer risk persists.

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 C, Organogenesis (about weeks 2 to 8 after conception). Malformations are chiefly caused during organogenesis, and CNS effects are important during 8 to 15 weeks.

Why is "Immediately before delivery" not the answer?

Delivery is too late for structural malformation.

Why is "Pre-implantation (first 10 days)" not the answer?

Pre-implantation shows an all-or-none effect.

Why is "Third trimester" not the answer?

Third trimester carries less risk of malformation, though cancer risk persists.

What concept does this question test?

It tests Radiation effects: fetal exposure in Radiology. Pre-implantation exposure follows an all-or-none pattern, with death or normal development. Deterministic fetal effects are not expected below about 100 mGy.

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 effects: fetal exposure?

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.