Shockwave Transducer Diffuser for Lithotripter Cavitation Control
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Solution Overview
Problem
Medical shockwave devices, such as lithotripters, generate cavitation cavities that cause tissue damage and injuries like hematoma, and existing solutions either compromise the effectiveness of shockwaves or require device deactivation upon cavitation detection.
Innovation Solution
Incorporating a diffuser with a material having a different propagation velocity than the shockwave medium, positioned at the exit aperture, to alter the phase and amplitude of shockwaves, reducing constructive interference and thus minimizing cavitation damage without affecting the treatment's efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shockwave transducer generates high intensity shockwaves for effective treatment, then treatment effectiveness is improved, but cavitation cavities are generated causing tissue damage
Solution Approach 1:
A diffuser element is introduced as an intermediary component between the shockwave source and the treatment medium. This diffuser modifies the shockwave characteristics by altering phase and amplitude through its specific acoustic impedance, reducing constructive interference that leads to cavitation while preserving therapeutic effectiveness at the target site.
Solution Approach 2:
The diffuser element is positioned specifically at the exit aperture of the shockwave transducer, creating a localized modification of shockwave properties. This allows the shockwaves to maintain high intensity at the focal treatment site while having reduced cavitation potential in the surrounding tissue areas where the diffuser operates.
2Object-affected harmful factors
If device deactivates upon cavitation detection to prevent tissue damage, then tissue damage is reduced, but treatment continuity is interrupted
Solution Approach 1:
The diffuser element performs preliminary modification of shockwave characteristics before the shockwaves enter the treatment medium. By pre-altering the phase and amplitude distribution, the diffuser prevents cavitation formation in advance, eliminating the need for treatment interruption or device deactivation while still protecting against tissue damage.
3Object-affected harmful factors
If diffuser material has different propagation velocity than shockwave medium, then cavitation is reduced, but device complexity increases
Solution Approach 1:
The diffuser element utilizes a material with specifically selected acoustic properties, particularly different acoustic impedance and sound propagation velocity compared to the treatment medium. This parameter change creates the necessary phase and amplitude modifications to reduce cavitation. The element can be a simple geometric structure such as a plate or array of elements, avoiding complex mechanisms while achieving the desired effect through material property selection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The diffuser effectively reduces the size and occurrence of cavitation cavities, minimizing tissue damage while maintaining the effectiveness of shockwaves, allowing continuous treatment without interruption.
Implementation Method 1
a diffuser with a material having a different propagation velocity than the shockwave medium, positioned at the exit aperture, to alter the phase and amplitude of shockwaves
Implementation Method 2
reducing constructive interference and thus minimizing cavitation damage
Implementation Method 3
The shockwave source may be configured to generate shockwaves. Typically, a shockwave may be a type of propagating disturbance in a medium, e.g. fluid (e.g. water), gas or plasma
Implementation Method 4
Cavitation cavities, also called cavitation bubbles or cavitation voids, are created by the negative pressure wave associated with the shockwave
Data Source
AI summary
A shockwave transducer for a lithotripter includes a shockwave source and a body with an exit aperture. The transducer is configured to generate a shockwave propagating from the body and through the exit aperture. The body comprises at least one diffuser, which engages into the shockwave propagating from the body. This diffuser includes a material characterized by a propagation velocity of the shockwave that is different from the propagation velocity of the shockwave in the surrounding medium.