Because of their small size, radiography of infants and very small children may not be possible with X-ray equipment utilizing which component?

• A. Phototimers
• B. Filtration
• C. Gonadal shielding
• D. Collimation

Answer: (A)

The main idea is how automatic exposure control works and why it can fail with very small patients. A phototimer is a type of AEC that relies on a light-sensing detector to terminate the exposure once a preset amount of exit light reaches the detector. When imaging infants or very small children, the tiny body produces a much smaller exit signal, and that signal may be too weak or poorly distributed to trigger the phototimer reliably. As a result, the exposure may not be terminated correctly, leading to inconsistent or unsuitable images. For this reason, radiography of very small patients is often not feasible with equipment that uses phototimers, and manual technique or systems with ionization-chamber AEC (which respond directly to the beam in the patient’s path) are preferred. Filtration, gonadal shielding, and collimation relate to beam quality and protection and don’t inherently prevent imaging of small patients with proper technique.