Characterization of the acoustic field of a clinical electromagnetic shockwave therapy device.

Abstract

Extracorporeal shockwave therapy devices are used in clinical settings for different medical applications such as orthopedics and urology. Having several clinical devices out in the field creates a challenge when comparing treatments and energy deposition mechanisms between different devices. In this work, the field of an electromagnetic shockwave device (Duolith SD1 T‐Top, Storz) was characterized using a fiber optic hydrophone (FOPH2000, RP Acoustics). The acoustic field from two hand‐held probes was measured: one probe was focused (with different length coupling cones) and the second one was a ballistic (radial therapy) probe. With the focused probe, measured pressures ranged from 45 MPa peak‐positive to 12 MPa peak‐negative. Axial and transverse beam profiles were acquired while analyzing the peak‐positive and peak‐negative pressures at each machine energy level and pulse repetition frequency. The focused source showed an extended −6 dB peak‐positive focal region along the axis of propagation and shorter in the orthogonal planes to the propagation (30 × 3 × 3 mm3). Linear scans along the axis of propagation showed quadratic decay distal to the focus. Measured peak‐negative pressures were higher pre‐focal than post‐focal. The results compared qualitatively, but not quantitatively with manufacturer specifications. [Work supported by NIH AR053652.]