Due to the anode heel effect, the X-ray beam intensity is greatest along which part of the beam?

Due to the anode heel effect, the X-ray beam intensity is greatest along which part of the beam?

• A. Anode end
• B. Center
• C. Edge opposite the cathode
• D. Cathode end

Answer: (D)

Intensity variation along the X-ray beam occurs because the anode is angled and photons are produced inside it. Photons exiting toward the cathode end encounter less material on their path, so fewer are absorbed before leaving the tube. Photons exiting toward the anode end must pass through more of the anode (the heel), leading to more attenuation and a weaker beam there. The result is the beam being strongest at the cathode end and weakest at the anode end. This effect grows with steeper anode angles and larger field sizes. In practice, you can place the thicker part of the anatomy toward the cathode end to take advantage of the higher intensity and help even out exposure.

Intensity variation along the X-ray beam occurs because the anode is angled and photons are produced inside it. Photons exiting toward the cathode end encounter less material on their path, so fewer are absorbed before leaving the tube. Photons exiting toward the anode end must pass through more of the anode (the heel), leading to more attenuation and a weaker beam there. The result is the beam being strongest at the cathode end and weakest at the anode end. This effect grows with steeper anode angles and larger field sizes. In practice, you can place the thicker part of the anatomy toward the cathode end to take advantage of the higher intensity and help even out exposure.