ABSTRACT
Objective To design an electrical system of extracorporeal shock wave lithotripter for children and adults uses.Methods The shock wave kernel parameters of child energy section of Dornier Delta Ⅱ lithotripter were tested such as peak sound pressure,pressure pulse width and pressure pulse rise time,and then energy calibration was executed for HK.ESWL008 child extracorporeal shock wave lithotripter to make the kernel parameters of the two lithotripters the same or similar to each other.An electrical system was designed with PLC system as the core control unit,involving in wave source 3D motion,large and small C-arms motion,water circulation system,B-type ultrasound positioning system,high-frequency X-ray imaging system,high-voltage condenser charging and discharging system,console and bedside-box-controlled display system as well as electromagnetic compatibility.Results Within A,B,C,1 and 2 energy sections for child lithotripsy the maximum and average differences between the kernel parameters of the two lithotripters were 7.1％ and 3.8％ respectively.There was no difference between the clinical experience by the two lithotripters,and HK.ESWL-008 child extracorporeal shock wave lithotripter passed EMC and safety detections by Guangdong Medical Devices Quality Surveillance and Test Institute of CFDA.Conclusion HK.ESWL-008 child extracorporeal shock wave lithotripter can be used for children lithotripsy clinically.
ABSTRACT
Objective To measure the maximum dissolved oxygen concentration of the lithotripter to avoid visible air bubbles during lithotripsy.Methods The present situation of degassing of lithotripter and clinical requirements for water were introduced.Under the following conditions of 7.5 L water capacity,35 L/h water flow,ambient temperature 28 ℃,17 kV,60 shocks per minute,the lithotripter discharged 10 000 shocks continuously without a visible air bubble in the circulating water,then the dissolved oxygens in the water were measured by using AZ8403 dissolved oxygen meter.The maximum value of dissolved oxygen in the water was determined therefore without a visible air bubble.Results The visible tiny air bubble emerged during lithotripsy if the dissolved oxygen in the water was above 3.37 mg/L and ambient temperature was about 28 ℃;the bubble could be avoided if the dissolved oxygen was under 3.34 mg/L and ambient temperature was about 28 ℃.Conclusion The circulating water with dissolved oxygen concentration less [han 3 mig/L and about 28 ℃ ambient temnperature are recommended for the electromagnetic extracorporea] shock wave lithotripter during lithotripsy.