Objective:To study the relationship between coagulation necrosis and cavitation in bovine lens induced by PHIFU with different parameters

and to explore the best way of irradiation. Methods:Different sound power and duty cycle of PHIFU(group A

control groups:60 W- 100%

group B:120 W- 50%

group C:240 W- 25%

group D:500 W- 12%) was used to irradiate bovine lens;the real-time formation of coagulation necrosis was recorded using high-speed imaging device;the acoustic scattering at the focal region was recorded by PCD system

and then the relationship between the irradiation process and cavitation was analyzed

and the effects of irradiation parameters was compared. Results:Coagulation necrosis was occurred in each group. At the beginning of irradiation

the root-mean-square(RMS)was increased in groups C and D

and the corresponding average time of appearing coagulation necrosis was(2.63±0.71) s and(2.45±0.68) s

respectively. In group D

the occurrence time of coagulation necrosis was the shortest

the volume was the maximum

the energy efficiency factor(EEF) was the minimum

and the cavitation occurred acutely. Conclusion:Under the same total dose of radiation PHIFU

sound power=500 W

duty cycle=12% is the best. Cavitation occurs earlier than the appearance of coagulation necrosis.