During ultrasound therapy, the therapist's hands are at risk for what type of radiation?

• A. Parasitic radiation
• B. Ionizing radiation
• C. Thermal radiation
• D. Non-ionizing radiation

Answer: (A)

Ultrasound therapy uses non-ionizing acoustic energy, but the hands of the therapist can receive unintended exposure from the device. This specific, unwanted transfer of ultrasound energy to the operator is described as parasitic radiation. It can cause localized heating of the skin if the transducer is held in place too long or at too high an intensity, so proper technique and safety measures help minimize this risk.

Ionizing radiation, like X-rays, isn’t produced by ultrasound. Thermal radiation refers to heat from electromagnetic waves (infrared), not sound waves. The general category of ultrasound energy is non-ionizing, but the term that best captures the operator’s incidental exposure during therapy is parasitic radiation.