Which of the following affects receptor exposure?

Which of the following affects receptor exposure?

• A. Atomic mass of the x-ray tube anode
• B. X-ray tube angle
• C. Atomic number of the cathode filament
• D. Filament thickness

Answer: (B)

The main idea tested is how the geometry of the x-ray tube, specifically the anode angle, shapes how much radiation reaches the image receptor. When the tube is angled, the anode heel effect comes into play, causing beam intensity to vary across the field. Photons are more absorbed on the anode side of the beam, so that side receives less exposure, while the opposite (cathode) side gets more. Therefore, changing the tube angle directly alters receptor exposure by changing this distribution of beam intensity. The other factors don’t directly control how much radiation reaches the receptor in a given exposure. The anode’s atomic mass doesn’t determine beam intensity in clinical practice; the filament’s atomic number doesn’t govern emission in a way that affects receptor exposure; and filament thickness mainly affects emission capacity, not the exposure pattern across the image under typical technique settings.

The main idea tested is how the geometry of the x-ray tube, specifically the anode angle, shapes how much radiation reaches the image receptor. When the tube is angled, the anode heel effect comes into play, causing beam intensity to vary across the field. Photons are more absorbed on the anode side of the beam, so that side receives less exposure, while the opposite (cathode) side gets more. Therefore, changing the tube angle directly alters receptor exposure by changing this distribution of beam intensity.

The other factors don’t directly control how much radiation reaches the receptor in a given exposure. The anode’s atomic mass doesn’t determine beam intensity in clinical practice; the filament’s atomic number doesn’t govern emission in a way that affects receptor exposure; and filament thickness mainly affects emission capacity, not the exposure pattern across the image under typical technique settings.