In this work we present the design of a portable radio-frequency diathermy (RFD) prototype and its initial medical validation. The electronic circuit consists of a voltage-controlled oscillator, a low-frequency oscillator and a voltage amplifier powered by a rechargeable battery. Circuit was designed to develop a pulsed output of 120 V at a frequency ranging from 500 KHz to 1 MHz. The RFD circuit was implemented with commercially available components and assembled on a printed circuit board (PCB). The complete product, including flexible electrodes, was assembled on a 6 cm x 9 cm x 3 cm cabinet. Experimental results show that the output can reach a pulsed voltage of 84 Vpp and a current of 120 mA during 8 hours of continuous operation, which fulfills the autonomy requirement of portable devices for low power RFD applications. A comparative study according to physical rehabilitation protocol was carried out on a universe of 20 patients with lumbago disease with continuous RFD treatment using our prototype versus a traditional RFD treatment. Preliminary results show that muscle healing was more effective in patients with continuous RFD treatment, validating this prototype for therapeutic applications.
