Thicker part of anatomy should be placed under which aspect of the x-ray tube?

• A. Central ray
• B. Cathode
• C. Anode
• D. Collimator

Answer: (B)

Thicker parts should be placed under the cathode side of the tube because of the anode heel effect. This effect makes the X-ray beam intensity higher on the cathode side and lower on the anode side. By positioning the thicker anatomy where the beam is more intense, you ensure adequate penetration and image brightness without increasing overall exposure. The central ray is about directing the beam, the anode is the target that produces the X-rays, and the collimator shapes the beam—these aspects don’t determine where the thicker part should go.