Radiotherapy and nuclear medicine basics: brown fat on PET: 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 · Radiotherapy and nuclear medicine basics: brown fat on PET

Sample item

A young woman scanned in winter for lymphoma staging has symmetric intense FDG uptake in the supraclavicular and paravertebral regions. The corresponding CT shows fat attenuation without nodes. What is the most likely explanation?

AReactive thymic hyperplasiaBMuscle tension uptakeCPhysiological brown adipose tissue uptakeDLymphomatous nodal involvement

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

The answer and the reasoning

C. Physiological brown adipose tissue uptake

Brown fat is metabolically active when stimulated by cold or sympathetic activity and takes up FDG avidly. The symmetric distribution and fat attenuation on CT separate it from nodes. Warming the patient or giving a beta-blocker or benzodiazepine before the scan can reduce the uptake.

Option by option

A. Reactive thymic hyperplasia
Thymic hyperplasia lies in the anterior mediastinum.
B. Muscle tension uptake
Muscle uptake corresponds to muscle density, not fat, and is usually in the neck muscles themselves.
C. Physiological brown adipose tissue uptake (correct)
Correct. Cold-stimulated brown fat takes up FDG and lies in fat-density tissue.
D. Lymphomatous nodal involvement
Nodal disease corresponds to soft tissue nodes on CT, not fat attenuation.

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, Physiological brown adipose tissue uptake. Brown fat is metabolically active when stimulated by cold or sympathetic activity and takes up FDG avidly.

Why is "Reactive thymic hyperplasia" not the answer?

Thymic hyperplasia lies in the anterior mediastinum.

Why is "Muscle tension uptake" not the answer?

Muscle uptake corresponds to muscle density, not fat, and is usually in the neck muscles themselves.

Why is "Lymphomatous nodal involvement" not the answer?

Nodal disease corresponds to soft tissue nodes on CT, not fat attenuation.

What concept does this question test?

It tests Radiotherapy and nuclear medicine basics: brown fat on PET in Radiology. The symmetric distribution and fat attenuation on CT separate it from nodes. Warming the patient or giving a beta-blocker or benzodiazepine before the scan can reduce the uptake.

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 Radiotherapy and nuclear medicine basics: brown fat on PET?

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.