FRCR MCQ 4

Question 1

Which of the following is the correct definition of the mean glandular dose (MGD) in mammography?

Accepted Answer

The average dose absorbed by the glandular tissue of the breast, excluding skin dose

Answer

Mean glandular dose (MGD) is the primary dosimetric quantity in mammography, representing the average absorbed dose to glandular tissue, which is the radiation-sensitive component of the breast.

Question 2

A 35-year-old woman presents with haematuria. Ultrasound shows an echogenic renal mass with no acoustic shadowing. What is the most likely diagnosis?

Accepted Answer

Angiomyolipoma

Answer

Angiomyolipomas are typically echogenic on ultrasound due to their fat content, and absence of acoustic shadowing helps distinguish them from calculi.

Question 3

On plain radiograph, which pattern of periosteal reaction is most suggestive of an aggressive bone lesion?

Accepted Answer

Codman's triangle (interrupted periosteal reaction at the tumour margins)

Answer

Codman's triangle represents periosteum lifted and broken at the tumour margin, indicating aggressive growth that outpaces periosteal healing capacity.

Question 4

Which statement about the inverse square law as applied to X-ray imaging is correct?

Accepted Answer

Doubling the distance from the source reduces radiation intensity to one-quarter

Answer

The inverse square law states that intensity is inversely proportional to the square of the distance, so doubling the distance reduces intensity to 1/4 (1/2² = 1/4).

Question 5

In a patient with portal hypertension, which ultrasound finding directly confirms the diagnosis?

Accepted Answer

Reversal of flow (hepatofugal) in the portal vein on Doppler

Answer

Hepatofugal (away from the liver) flow in the portal vein on Doppler ultrasound is a direct haemodynamic sign of severe portal hypertension with portosystemic shunting.

FRCR - Fellow of the Royal College of Radiologists Practice Test

FRCR - Fellow of the Royal College of Radiologists Practice Test

FRCR MCQ 4