BNR: is the degree to which the US beam varies, the highest intensity within the beam relative to the average intensity of the soundhead
- clinical application: if the wand is not moving, the peak stays in one small area.... burns... keep soundhead moving!!
- effective radiating area
- ERA: the area of the transducer from which the US energy radiates
- general rule: tx area is 2x the size of the soundhead
- duration: 5-10 minutes for each tx area that is 2x the ERA
if the tx area is more than 2x the ERA: it is NOT creating the physiological effect intended