1MHz therapeutic ultrasound equipment

[ricromo]

I´m looking for an schema or electronic circuit for build an 1-3 1MHz therapeutic ultrasound equipment to use in treatment physiotherapeutic or kinesitherapy. 3W/cm2 in 1 MHz and 2.5 W in 3 MHz

Thanks

ricromo@latinmail.com

 

[Dr.EM]

1-3Mhz is not ultrasound and no transducer will operate anywhere near that high. You can build a radio transmitter for that frequency, but I can't see that will help anyone, radio waves of all frequencies are around us constantly.

 

[JimB]

1-3Mhz is not ultrasound and no transducer will operate anywhere near that high.

Not so.
Have a look at this link which starts of by stating the the most common frequencies used in medical electronics are in the range 0.5 to 10Mhz.
http://www.kayelaby.npl.co.uk/general_physics/2_4/2_4_6.html

Some years ago when I had some ultra sound scans, I asked what frequencies were being used, the highest one was (from memory) 13.5Mhz.

Consider the resolution of the image, if you want a resolution of 1mm, you will need a wavelength smaller than 1mm.

The speed of sound in water is about 1500m/s, so using the relationship Frequency = velocity/wavelength, we get f = 1500/0.001 = 1.5Mhz.

JimB

 

[ricromo]

The 1/3 MHz therapeutic equipment for physiotherapy treatment, are called ultrasound even they working in 1 MHz and 3 MHz(Xtal= diameter = 1" like 1 dollar coin) .

1 MHz works in profoundness body until 1 " or more
3 MHz works in superficial body, over skin

Thanks

 

[zevon8]

Have a look for "Diathermy", basically RF transmitters used to locally heat tissue. Lots of people were developing these in the 80's ... some went on to further developement, others just moved on.

 

[GoKid]

acoustic medium the key

I'm afraid you all have not recoginized the significance of acoustic medium in this discussion. Therapeutic ultrasound in the MHz range is only possible with a medium that has great propogation properties. Ultrasonic wave propogation through the air is poor above 100KHz. The jelly a physicial therapist puts between the ultrasound probe and the injured muscle for deep tissue massage via ultrasonics relies on the better wave propogation properties of the vicous jelly over that of air. You are at least 80% water (25% for you chronic Coca Cola drinkers) mixed with fat and muscle so the wave propogation through the body is still better than air, especially when the target area is rich with inflammatory by-products.

As for image resolution, it is not necessarily true that to go <.1mm you would have to have a wave that small. At least in distance measuring apps there are techniques to get sub-mm resolution with a 40KHz wave (around 8mm)!

GoKid!

 

[Hero999]

That's true, the highest transducer I've come across for use in air is 350kHz, I'd say that air is opaque to ultra sound above 1MHz or so, in fact probably lower, however water can trasmit ultrasound way above 10MHz.