Changing of output of ultrasound among before, after 1 and 2 months of use in a physical therapy clinic

Abstract

The current study verify the changes of power output of ultrasound at 3 different times including before use, after 1 and 2 months. Thirty-one Ultrasound instruments were measured by a Wattmeter for power output at 3, 6 and 10 watt of continuous wave form. In addition, the continuous wave form of 6 watt at the 2^nd and 3^rd minutes, and 6 watt of 50% duty cycle of pulse wave form before use in the physical therapy clinic, Faculty Physical Therapy, Mahidol University. The results showed that the mean and standard deviation of the 3 watts output of ultrasound before, after 1 and 2 month, yielded 3.02 + 0.72, 2.90 + 0.66, 2.82 + 0.52 respectively. While the output of 6 watts yielded 5.88 + 1.27, 5.85 + 0.95, 5.59 + 1.10 respectively. The output of 10 watts yielded 9.54 + 2.03, 9.32 + 1.32, 8.93 + 1.52, respectively. The 2^nd minute and 3^rd minutes at the output of 6 watt of continuous wave yielded 5.39 + 1.24, 5.68 + 0.99, and 5.68 + 1.23 respectively. The power output at the 3^rd minute yielded 5.33 + 1.26, 5.69 + 1.00, and 5.67 + 1.18 watts respectively. In the addition, the 50% duty cycle of pulse wave form at 6 watt is 5.33 + 1.26, 5.69 + 1.00, and 5.67 + 1.18 watts respectively. To compare of output of ultrasound between before and after 1 and 2 months, we found a significant different between before and after 1 month usage of the ultrasound at the output of 6 watt pulse 50%. Besides, there were a significant different between (P - value < 0.05) before and after 2 months usage of the ultrasound at the output of 3, 10 watt, 6 watt at 3^rd minute, continuous wave and 6 watt  pulse 50 % duty cycle. The suggestion of this study is that the physical therapy unit should reject the ultrasound brand which changed the power output more than 20 % of the expected power after 2 months usage.