How does receptor type influence dose efficiency and patient dose?

• A. Digital receptors require more exposure than film and have wider dynamic range.
• B. Digital receptors generally require less exposure than film and have a wider dynamic range.
• C. Film receptors require less exposure but have limited dynamic range.
• D. Receptor type has no effect on dose.

Answer: (B)

Receptor type determines how efficiently the imaging system converts x-ray energy into a usable signal and how tolerant it is to exposure variations. Digital receptors have a higher detective quantum efficiency and a much wider exposure latitude than film-screen systems. This means you can achieve the same diagnostic image quality with less exposure, and you can tolerate a broader range of exposures without compromising the image. With film, the dynamic range is more limited and exposure control is tighter, so higher or more precise exposure is often needed to avoid quantum mottle or distortion, which can drive up the patient dose.

That combination—the ability to produce adequate images at lower exposure and with more leeway to avoid repeats—makes digital receptors generally require less exposure and offer a wider dynamic range. The other statements conflict with these realities: digital does not require more exposure, and receptor type does affect dose due to differences in efficiency and latitude.