An in vitro and in vivo study on extracorporeal transducer optimization for high-intensity focused ultrasound to improve the safety and efficacy of breast tumor ablation.

OBJECTIVE:To observe the characteristics of a new extracorporeal high intensity focused ultrasound transducer, titled Haifu system JCQ-B, and to compare its safety and efficacy for breast ablation with the standard Haifu system JC transducer. MATERIALS AND METHODS:Ox liver with pig skin and pork ribs were prepared in a semi-sphere shape, served as in vitro acoustic model. The udders of female goats were used as in vivo acoustic model. Both in vitro and in vivo models were ablated by either JCQ-B or JC transducer. The morphology of biological focal region (BFR), the coagulative necrosis volume, and the temperature increase were observed and compared. RESULTS:The BFR morphology of JCQ-B transducer was circular both in vitro and in vivo, with a length-width ratio close to one. Under the same sonication parameters (sonication power, time and depth in tissue), coagulation necrosis volume caused by JCQ-B transducer was larger than that caused by JC transducer both in vitro and in vivo. The increase in temperature in the near and far acoustic pathways with JCQ-B transducer was significantly lower than that of JC transducer in vitro. After receiving high sonication energy during in vivo experimentation, there were no complications observed after the ablation of JCQ-B transducer, while small skin damage was observed after the ablation of JC transducer. CONCLUSIONS:The JCQ-B transducer improved the safety and efficacy of treatment by optimizing BFR morphology and ablation efficiency, which could be applied in the treatment of breast tumor.