A NEW ESTIMATION METHOD OF SPATIAL PEAK TEMPORAL AVERAGE INTENSITY AND SPATIAL PEAK PULSE AVERAGE INTENSITY IN HIFU FIELD

High intensity focused ultrasound( HIFU) inmedicine has been developed rapidly for more thanten years.It changes the situation of slowly ad-vancing in ultrasonic therapy. HIFU has become anew character of ultrasound in medicine.The ex-tracorporal lithotriptor,the pyrothrapy,the HIFUsurgery,the HIFU hemostasis,and the HIFUabortion are the most important progresses.Theyshow that the applications of ultrasound in therapywill have greater project than that in diagnosis1] .China has made m…

A NEW ESTIMATION METHOD OF SPATIAL PEAK TEMPORAL AVERAGE INTENSITY AND SPATIAL PEAK PULSE AVERAGE INTENSITY IN HIFU FIELD

A new estimation method of maximum intensity, such as I spta in CW and I sppa in PW, in high intensity focused ultrasound (HIFU) field for surgery was developed based on the measurements of acousic power and radical distribution of the relative acoustic pressure in the focal plane of the field. The acoustic power is measured by the radiation force balance or by the calorimetry. Using a miniature hydrophone to scan along several radial directions with the same angle intervals through the acoustic axis in the focal plane, several radial relative pressure distribution curves can be measured and thus the special cross section area related to the maximum intensity and be calculated. The quotient of the measured acousitc power to the special cross section area is the maximum acoustic intensity in the field. finally as an example, the acoustic field distribution of a CW system was measured and the maximum acoustic intensity estimated was given.