RESUMEN
Objective To study the killing effect of focused ultrasound activated-hematoporphyrin on H-22 and its optimum exposure time.Methods The distribution of hematoporphyrin in H-22 cells was measured by a fluorescence photometer,the uhrastructure changes were evaluated at different time with a scanning electron micro- scope after treatment with focused ultrasound at the frequency of 1.43 MHz and intensity of 1.0 W/cm~2, 2.0 W/cm~2,3.0 W/cm~2,respectively,in combination with HpD.Results The concentration of HpD in the H-22 cells reached its peak after being added to H-22 tumor cells for 45 minutes,which will produce the hest anti-tumor effect when activated by ultrasound.Morphological observation showed that HpD alone had a slight influence on H-22 cells;ULtrasound alone showed an anti-tumor effect on tumor cells,which was dosage-dependent.Ultrasound dia- thermy in combination with HpD has more effective in terms of its antitumor effect when compared with uhrasound dia- thermy alone.Conclusion The killing effect on H-22 tumor cells of sonodynamic treatment was dependent on the intensity of uhrasound and the content of HpD in the cells,as well as on the time of action of both uhrasound and HpD.