Radiation safety and radiobiology: bystander effect: 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: bystander effect

Sample item

In a cell culture, only a few cells are traversed by an alpha particle, yet micronuclei and chromosomal damage appear in neighbouring cells that were not hit. What is this phenomenon called?

ABystander effectBOxygen effectCAdaptive responseDSublethal damage repair

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

The answer and the reasoning

A. Bystander effect

The bystander effect describes biological damage in unirradiated cells caused by signals, such as cytokines and reactive species, passed from irradiated neighbours. It challenges the idea that damage is limited to cells directly hit. Other radiobiological effects concern oxygen dependence, priming doses and repair.

Option by option

A. Bystander effect (correct)
Correct. Unhit cells show damage through signalling from irradiated cells.
B. Oxygen effect
The oxygen effect is the increase in radiosensitivity with oxygen at the time of irradiation.
C. Adaptive response
Adaptive response is reduced damage after a small priming dose.
D. Sublethal damage repair
Sublethal damage repair is recovery between dose fractions, not damage in unhit cells.

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, Bystander effect. The bystander effect describes biological damage in unirradiated cells caused by signals, such as cytokines and reactive species, passed from irradiated neighbours.

Why is "Oxygen effect" not the answer?

The oxygen effect is the increase in radiosensitivity with oxygen at the time of irradiation.

Why is "Adaptive response" not the answer?

Adaptive response is reduced damage after a small priming dose.

Why is "Sublethal damage repair" not the answer?

Sublethal damage repair is recovery between dose fractions, not damage in unhit cells.

What concept does this question test?

It tests Radiation safety and radiobiology: bystander effect in Radiology. It challenges the idea that damage is limited to cells directly hit. Other radiobiological effects concern oxygen dependence, priming doses and repair.

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: bystander effect?

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.