Nuclear medicine: FDG PET preparation: 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 · Nuclear medicine: FDG PET preparation

Sample item

A diabetic patient referred for FDG PET-CT has a pre-injection blood glucose of 380 mg/dl. What is the appropriate action?

AGive double the FDG doseBInject normally, since glucose has no effectCReschedule or correct glycaemia, as high glucose competes with FDG and lowers tumour uptakeDReplace FDG with technetium MDP and call it a PET

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

The answer and the reasoning

C. Reschedule or correct glycaemia, as high glucose competes with FDG and lowers tumour uptake

FDG is a glucose analogue, so high blood glucose competes for transport and reduces tumour uptake, risking false-negative results. Glucose is therefore checked before injection and patients fast for several hours.

Option by option

A. Give double the FDG dose
Doubling the dose raises exposure without fixing competition.
B. Inject normally, since glucose has no effect
Glucose does affect FDG uptake and image quality.
C. Reschedule or correct glycaemia, as high glucose competes with FDG and lowers tumour uptake (correct)
Correct. Hyperglycaemia degrades FDG PET and should be corrected first.
D. Replace FDG with technetium MDP and call it a PET
Technetium MDP is a single photon bone tracer and not a PET agent.

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 C, Reschedule or correct glycaemia, as high glucose competes with FDG and lowers tumour uptake. FDG is a glucose analogue, so high blood glucose competes for transport and reduces tumour uptake, risking false-negative results.

Why is "Give double the FDG dose" not the answer?

Doubling the dose raises exposure without fixing competition.

Why is "Inject normally, since glucose has no effect" not the answer?

Glucose does affect FDG uptake and image quality.

Why is "Replace FDG with technetium MDP and call it a PET" not the answer?

Technetium MDP is a single photon bone tracer and not a PET agent.

What concept does this question test?

It tests Nuclear medicine: FDG PET preparation in Radiology. Glucose is therefore checked before injection and patients fast for several hours.

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 Nuclear medicine: FDG PET preparation?

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.