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. 2013 May;27(5):631–639. doi: 10.1089/end.2012.0611

FIG. 4.

FIG. 4.

Peak positive (P+) and negative (P−) pressures for SWs collected at steps along the acoustic axis (Z-axis) for the LG-380 and HM3 lithotripters. Data are for SWs (mean of 30–40 SWs) fired during the working lifetime of the electrodes (SWs 900–1500, PL-9 for LG-380; SWs 500–900, 18 kV for HM3). Zero on the Z-axis marks the target point of the LG-380 and the F2 focal point of the HM3. Maximum P+ (∼30 MPa) and P− (∼−4.5 MPa) for the LG-380 was located ∼30–35 mm postfocal. Maximum P+ (∼38 MPa) for the HM3 was at the F2 focal point, while the greatest negative pressure (∼−7.5 MPa) was located ∼20–25 mm prefocal. This illustrates key differences in the acoustic properties of the two lithotripters.