Sasaki Kazuaki, Azuma Takashi, Kawabata Ken-Ichi, Umemura Shin-Ichiro, Tanaka Ryou, Yamane Yoshihisa, Shimoda Minoru
Central Research Laboratory, Hitachi, Ltd, Kokubunji, Tokyo, Japan.
J Vet Med Sci. 2006 Aug;68(8):839-45. doi: 10.1292/jvms.68.839.
The treatment time needed for high-intensity focused ultrasound (HIFU) ablation might be decreased substantially by using the split-focus approach, so we made a prototype 4.2-MHz split-focus therapeutic transducer combined with a small 6.5-MHz imaging ultrasonic probe for transrectally treatment of canine prostatic cancer and used it to experimentally evaluate the feasibility of using split-focus transrectal HIFU to ablate canine prostatic tissue without injuring surrounding tissues. The prostates of 5 dogs were transrectally treated with split-focus ablation at a peak intensity in the water of 1.7 kW/cm(2) for 4 s (4 shots) under the guidance of ultrasonic B-mode imaging. After ultrasonic exposure, the prostates became stiff because of thermal effect of HIFU. For the first 3-5 days after treatment, dogs were catheterized daily for urinary management and treated with oral antibiotics to prevent urinary tract infection. The dogs were able to urinate normally by a week after. Within two weeks a large centrally located cystic cavity had formed in the prostate by replacing the necrotic parenchyma around the prostatic urethra. Necropsy three months after treatment found the rectum and prostate capsule to be normal grossly and histologically. The 4 shots of split-focus HIFU destroyed the prostatic parenchyma and created a prostatic cavity 0.34-0.45 cm(3) in volume without injuring surrounding tissues. These results suggest that split-focus HIFU ablation could be used for noninvasive treatment of prostatic cancer in dogs.
通过采用分裂聚焦方法，高强度聚焦超声（HIFU）消融所需的治疗时间可能会大幅缩短。因此，我们制作了一个4.2兆赫兹的分裂聚焦治疗换能器原型，并将其与一个小型6.5兆赫兹成像超声探头相结合，用于经直肠治疗犬前列腺癌，并以此实验评估采用分裂聚焦经直肠HIFU消融犬前列腺组织而不损伤周围组织的可行性。在超声B模式成像引导下，对5只犬的前列腺进行经直肠分裂聚焦消融治疗，水中峰值强度为1.7千瓦/平方厘米，持续4秒（4次发射）。超声照射后，由于HIFU的热效应，前列腺变硬。治疗后的前3至5天，每天为犬进行导尿以管理尿液，并给予口服抗生素以预防尿路感染。一周后犬能够正常排尿。两周内，前列腺内形成了一个位于中央的大囊性腔，取代了前列腺尿道周围的坏死实质。治疗三个月后尸检发现，直肠和前列腺包膜在大体和组织学上均正常。4次发射的分裂聚焦HIFU破坏了前列腺实质，形成了一个体积为0.34 - 0.45立方厘米的前列腺腔，且未损伤周围组织。这些结果表明，分裂聚焦HIFU消融可用于犬前列腺癌的无创治疗。
