Effect of pulse characteristics on temperature rise due to ultrasound absorption at a bone/soft-tissue interface.
The transient temperature rise at a bone/soft-tissue interface is an important quantity in the safety evaluation of procedures involving trains of high-intensity ultrasound pulses. Mathematical models based upon the time-averaged intensity of the pulse train can provide rapid estimates of the temperature rise, but are known to underestimate the temperature rise during the on-time of the pulse. This paper extends a previous analytical model to account for pulse shape, and provides error estimates for simulations employing time-averaged intensities. A simple analytic expression for the interface temperature that accounts for both bone and soft-tissue properties is provided. The analytic expression agrees well with temperature rise predictions based upon the finite-element method, when the insonation time is large compared to the pulse repetition period. In this case of large relative insonation time, the pulse shape is found to be inconsequential.
Myers
Matthew R
MR
Center for Devices and Radiological Health, HFZ-170, U.S. Food and Drug Administration, Rockville, Maryland 20852, USA. matthew.myers@fda.hhs.gov
D000042:Absorption; D001842:Bone and Bones; D006801:Humans; D008962:Models, Theoretical; D018482:Muscle, Skeletal; D013696:Temperature; D013997:Time Factors; D014463:Ultrasonography