近日，加拿大研究人员在美国新一期《国家科学院院刊》（PNAS）上报告说，动物实验显示，一种超声波疗法能让肿瘤对放射性治疗更加敏感。
放疗主要通过破坏DNA及肿瘤血管来摧毁肿瘤。微泡在超声激发的情况下，可以破坏病理结构薄弱的肿瘤新生血管。
研究人员通过静脉向实验鼠乳腺肿瘤部位注射了微泡，然后让该区域接触能使微泡破裂的超声波频率，部分肿瘤随后又接受了放疗。结果发现，这种组合治疗造成的肿瘤细胞死亡数比单独使用放疗要多出约10倍，相对于只使用放疗，组合疗法重复治疗能延长实验鼠的存活时间，并延缓肿瘤的生长。研究人员所用的微泡是微米直径的惰性气体球。
研究人员表示，放疗辅以超声波激发的微泡可能会增加癌症疗法的功效，并减少所需放疗的总剂量。（生物谷Bioon.com）
doi:10.1073/pnas.1200053109
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Tumor radiation response enhancement by acoustical stimulation of the vasculature
Gregory J. Czarnotaa,b,c,d,1, Raffi Karshafianc,d,e, Peter N. Burnsc,d, Shun Wonga,b,d, Azza Al Mahroukia,c, Justin W. Leea,b,c,d, Amanda Caissiea,c, William Trana, Christina Kima,c,d, Melissa Furukawaa,c, Emily Wonga,c, and Anoja Gilesa,c
We have discovered that ultrasound-mediated microbubble vascular disruption can enhance tumor responses to radiation in vivo. We demonstrate this effect using a human PC3 prostate cancer xenograft model. Results indicate a synergistic effect in vivo with combined single treatments of ultrasound-stimulated microbubble vascular perturbation and radiation inducing an over 10-fold greater cell kill with combined treatments. We further demonstrate with experiments in vivo that induction of ceramide-related endothelial cell apoptosis, leading to vascular disruption, is a causative mechanism. In vivo experiments with ultrasound and bubbles permit radiation doses to be decreased significantly for comparable effect. We envisage this unique combined ultrasound-based vascular perturbation and radiation treatment method being used to enhance the effects of radiation in a tumor, leading to greater tumor eradication.
