Question

In CT geometry:

a. There are typically two focal spots and the smallest is 0.6 mm

b. The heating capacity is 0.4 MJ

c. The filter in first-generation scanners was copper to remove high-energy photons and aluminium for low-energy photons

d. Post-patient collimation is necessary in a multi-slice scanner to get an accurate thickness e. A bow tie filter is used to reduce scatter at the periphery of the image

Answer 1

a. True.

b. False. The heating capacity is around 4 MJ.

c. False. In first-generation scanners, cooper was used to remove low-energy photons.

d. False. In a single-slice scanner, post-patient collimation is used to reduce scatter when the slice thickness is less than the collimator and also to get an accurate thickness.

e. False. The main purpose of the bow tie filter is to equalize the dose throughout an elliptical shaped body.