Thermochromic materials for the visualisation of thedistribution of time-averaged intensity within an ultrasonic field
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Ultrasound is widely used for physiotherapy, treatment headstypically operating in the frequency range 1 to 3 MHz.
For safe and effective application of ultrasound, standards havebeen developed specifying key quantities such as the EffectiveRadiating Area, AER(IEC 61689).
The Beam Non-uniformity Ratio, RBN(IEC 61689), can be used to identify 'hot-spot' transducers. For physiotherapy treatmentheads, RBN must be less than 8.
Here, we describe a method that exploits a Thermochromic (TC) material to provide a rapid (currently qualitative) visualisation of the acoustic intensity distribution.