A small anode angle results in which two of the following?

A small anode angle results in which two of the following?

• A. Decreased focal spot size and Decreased heat capacity
• B. Increased focal spot size and Increased heat capacity
• C. Decreased focal spot size and Increased heat capacity
• D. Increased focal spot size and Decreased heat capacity

Answer: (A)

A small anode angle changes how the focal spot is projected onto the image and how heat is distributed on the target. When the angle is reduced, the projected or effective focal spot becomes smaller, which sharpens the image because X-rays are emitted from a more confined area. At the same time, the heating area on the anode is more limited due to the steeper geometry, so the same electron beam’s heat is concentrated over a smaller surface. This concentrates heat and reduces the amount of heat the anode can safely absorb before risk of damage, i.e., the heat capacity decreases. So the combination you get is a smaller focal spot and a lower heat capacity.

A small anode angle changes how the focal spot is projected onto the image and how heat is distributed on the target. When the angle is reduced, the projected or effective focal spot becomes smaller, which sharpens the image because X-rays are emitted from a more confined area. At the same time, the heating area on the anode is more limited due to the steeper geometry, so the same electron beam’s heat is concentrated over a smaller surface. This concentrates heat and reduces the amount of heat the anode can safely absorb before risk of damage, i.e., the heat capacity decreases. So the combination you get is a smaller focal spot and a lower heat capacity.