I've just been reading some details about the cavitation effect of low-frequency ultrasound
I was not aware that frequencies like 18 kHz could cause cavitation, but it seems this frequency is near to the optimum range of cavitation-inducing acoustic frequencies.
So I am now wondering whether as a result of cavitation from the 18 kHz sound wave, there may be some risks of damage to kidney cells
is where sound waves create microscopic bubbles
in a liquid (the bubbles consisting of vapour).
When these tiny bubbles collapse, they create shock waves
, and these shock waves can damage nearby material. In the case of machinery immersed in a liquid, such as a ship's propellor, the shock waves from cavitation can damage the metal. These shock waves are also the basis for ultrasonic cleaning baths.
In the case of ultrasonic cavitation machines for fat loss, these apparently work by creating cavitation bubbles and shock waves, and the shock waves will rupture the walls of the fat cells
, thereby causing the fat they contain to drain out. In this way, the cavitation machine can reduce fat under the skin.
But the fact that ultrasonic cavitation machines can damage fat cells raises the issue of safety, as cavitation might also damage kidney cells.
Presumably the damage is transient, and the ruptured walls will repair themselves. But nevertheless, these shock waves can have strong effects on cells and tissues.
Until today, I was not aware that audible sound frequencies like 18 kHz could cause cavitation.
This then shines a new light on the adverse effects I experienced from using 18 kHz on my kidneys. The adverse effects I experienced may not necessarily come from disrupted biofilm, but might come from some negative impact on the kidneys themselves.
The Ideal frequency for Cavitation (cavi lipo machine) is between (20kHz and 30kHz).
Beware of knock off ultrasound machines that have a frequency of (40 to 60 KHz) because this is too weak and it cannot penetrate into the fat (adipose) or create enough disturbance in the cell to cause cavitation.
Many home versions for safety reasons work at this frequency but produce poor or no results at all.
So it seems that consumer home ultrasonic cavitation machines for fat loss are set to a frequency of 60 kHz to make them less efficient at rupturing fat cells; the more effective cavitation frequencies between 20 kHz and 30 kHz are reserved for professional machines.
Since 18 kHz is just outside the most effective cavitation frequency range of 20 kHz and 30 kHz, we can assume that 18 kHz will induce powerful cavitation effects. And possibly these effects could risk causing some damage to tissues.
So I think it would be wise to do some further research on the safety aspects of cavitation frequencies like 18 kHz, before proceeding with placing such sound waves on the kidneys.
using a 28.48 kHz ultrasound continuously applied to the skin of rabbits for 24 hours, at two different power levels of 100 mW/cm2 and 300 mW/cm2. The power level of 100 mW/cm2 showed no adverse effects, but at 300 mW/cm2 some tissue damage to the skin was noted after 24 hours.
Ultrasonic frequencies which do not produce cavitation may be safer.