Radiotherapy and nuclear medicine basics: MAA shunt study before radioembolisation: 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: MAA shunt study before radioembolisation

Sample item

Before yttrium-90 radioembolisation of hepatocellular carcinoma, a Tc-99m MAA scan is performed through the hepatic artery. What is the main purpose?

ATo quantify lung shunting and detect extrahepatic depositionBTo estimate the glomerular filtration rateCTo assess portal vein patencyDTo measure the hepatic synthetic function

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

The answer and the reasoning

A. To quantify lung shunting and detect extrahepatic deposition

Tc-99m MAA injected into the hepatic artery mimics the Y-90 microspheres, showing how much bypasses the tumour to the lungs and whether it reaches the stomach or duodenum. A high lung shunt fraction limits the safe dose.

Option by option

A. To quantify lung shunting and detect extrahepatic deposition (correct)
Correct. The MAA scan estimates lung shunt fraction and extrahepatic deposition before treatment.
B. To estimate the glomerular filtration rate
GFR is measured with DTPA clearance or serum creatinine, not with a hepatic artery MAA injection.
C. To assess portal vein patency
Portal vein patency is assessed with Doppler ultrasound or cross-sectional imaging.
D. To measure the hepatic synthetic function
Hepatic synthetic function is assessed with blood tests such as albumin and INR.

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, To quantify lung shunting and detect extrahepatic deposition. Tc-99m MAA injected into the hepatic artery mimics the Y-90 microspheres, showing how much bypasses the tumour to the lungs and whether it reaches the stomach or duodenum.

Why is "To estimate the glomerular filtration rate" not the answer?

GFR is measured with DTPA clearance or serum creatinine, not with a hepatic artery MAA injection.

Why is "To assess portal vein patency" not the answer?

Portal vein patency is assessed with Doppler ultrasound or cross-sectional imaging.

Why is "To measure the hepatic synthetic function" not the answer?

Hepatic synthetic function is assessed with blood tests such as albumin and INR.

What concept does this question test?

It tests Radiotherapy and nuclear medicine basics: MAA shunt study before radioembolisation in Radiology. A high lung shunt fraction limits the safe dose.

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 Radiotherapy and nuclear medicine basics: MAA shunt study before radioembolisation?

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.