Which instrument is used to measure the radiation output of X-ray machines?

• A. Personal Dosimeter
• B. Radiation Survey Device
• C. Scintillation Detector
• D. Film Badge

Answer: (B)

Measuring the X-ray machine’s output requires an instrument that provides real-time readings of the radiation field in the beam. A radiation survey device is designed for this purpose; it typically uses an ionization chamber to measure the exposure rate (or air kerma) at a defined distance from the tube, giving a direct measure of the machine’s output. This kind of instrument lets you verify calibration, monitor tube output, and assess shielding, all in the moment. Personal dosimeters and film badges, by contrast, record the dose accumulated by a person over time rather than the beam’s instantaneous output, so they’re not used to measure machine output. A scintillation detector is a general detector for detecting radiation but is not the standard tool specifically used to quantify X-ray tube output in clinic QA and calibration.