Short wave diathermy traditionally uses which frequencies?

• A. 13, 27, or 45 MHz
• B. 60 Hz
• C. 100 MHz
• D. 2.4 GHz

Answer: (A)

Shortwave diathermy uses radiofrequency energy in the shortwave portion of the spectrum to generate heat within tissues. Historically, medical SWD devices operated in the roughly 10–100 MHz range, with common frequencies around 13, 27, and 45 MHz. These frequencies allow energy to penetrate to deeper tissue layers while still being controllable with applicators and duty cycles.

Why these frequencies fit: at these RF bands the heating effect is achieved primarily through dielectric (or magnetic) interactions with tissue, producing deeper heating than lower-frequency methods and enabling effective therapy for musculoskeletal conditions when used properly. The other options fall outside the traditional shortwave window or belong to different modalities: 60 Hz is mains power frequency and not used for diathermy heating; 100 MHz sits higher in the RF range and is not the standard shortwave band for diathermy; 2.4 GHz is in the microwave range and represents a different heating modality with distinct safety and penetration characteristics.