Suitability of Self-Fabricated Solid Tissue Phantom for Quality Assurance Examination of Shortwave Diathermy (SWD) Unit

摘要

Diathermy is commonly used treatment method for pain relief in musculoskeletal tissue, rheumatisms, inflammation, etc., by which the increased temperature in tissue induces better blood perfusion and quickens the healing process. But improper maintenance and incorrect handling might lead to degrade the output power or may cause serious burns, respectively. So correct regular QA measurements for the output power would be necessary, in order to give the correct and safe treatment plan. A suitable tissue phantom is then needed to accomplish this task. For this purpose, a glycerol-based solid tissue phantom has been self-fabricated with insertion of four precision temperature sensors (LM 35) at locations of 1.0 cm, 1.5 cm, 2.0 cm, and 2.5 cm from the surface (each of which are 2 cm laterally separated). Prior calibration these four sensors for temperature range of 20-50°C (using a calibrated temperature calibrator) show very good accuracy and precision properties. The phantom is then tested by exposing it with RF waves output of SWD unit with time variation of 2-14 min (step 2 min), and output power variation of 20% - 80% of its maximum power (incremental step of 20%).