HIFU“帽式”消融模式的离体及活体动物实验研究

发布时间：2018-03-16 18:29

本文选题：高强度聚焦超声　切入点：帽式消融　出处：《重庆医科大学》2017年硕士论文　论文类型：学位论文

【摘要】：研究背景:高强度聚焦超声(High intensity focused ultrasound,HIFU)作为一种新型的微无创肿瘤治疗方法,以其不开刀、不流血、不良反应少等特点,逐渐被大众认可,成为众多肿瘤的替代治疗方式之一。然而,由于传统HIFU采用的“点-线-面-体”的辐照方式,消融过程复杂的同时也存在肿瘤内部能量重叠,导致过度消融,能量浪费,降低了治疗效率。加之超声波的衰减、HIFU本身的技术限制,以及部分肿瘤血供丰富、体积大、位置深等因素,HIFU完整“切除”肿瘤所需时间较长,缩短治疗时间又会导致组织残留。这些因素制约着HIFU技术的进一步推广和发展。增效相关的研究多从改变声学环境的角度推进,改进消融方法方面的研究较少。基于超声的反射、折射等物理特性,本文从改进消融方法学的角度提出了帽式消融,以互成夹角的两个面促进超声能量向帽式结构内部聚集,减少能量向周围正常组织扩散的同时也减少了内部能量的过度重叠,从而减少能量浪费,增效HIFU治疗。研究目的:探讨HIFU帽式消融在离体及活体实验中的可行性,对比不同参数组合下帽式消融的消融效果,寻找最优消融方法,增效HIFU治疗。材料与方法:实验分为离体牛肝及活体兔肝两部分。离体实验中,通过改变两个辐照面间的夹角、辐照顺序,得到不同参数组合下的凝固性坏死。同时,将帽式消融模式与传统消融模式作对照,对比两种消融模式的消融效果。将得出的结论应用于活体兔肝中,验证其在活体中的可行性。消融结束后将肝脏组织切片,行TTC染色,观察凝固性坏死形态,计算凝固性坏死体积及能效因子,对比不同参数及条件下的消融效果。结果:1、离体及活体实验中,各组均形成肉眼及镜下可见的凝固性坏死,坏死体积远大于辐照区体积;2、改变辐照夹角后形成的凝固性坏死的形态差异显著,但凝固性坏死体积差异无统计学意义;3、不同辐照顺序形成的凝固性坏死体积有明显差异;4、一定条件下,帽式消融模式可较传统消融模式缩短消融时间,减少总能量消耗,提高辐照效率。结论:帽式消融模式在离体及活体中均具有可行性。同时,一定条件下,帽式消融模式可较传统消融模式实现更高效的消融。
[Abstract]:Background: high intensity focused ultrasound (HIFU), as a new type of microinvasive tumor therapy, has been gradually accepted by the public because of its characteristics of no operation, no bleeding, few adverse reactions and so on. However, because of the point, line, plane and body irradiation mode adopted by traditional HIFU, the process of ablation is complicated and the internal energy overlaps, which leads to excessive ablation and energy waste. It reduces the therapeutic efficiency. In addition, the attenuation of ultrasound and the technical limitation of HIFU itself, as well as some factors such as abundant blood supply, large volume, deep position and so on, take a long time to "remove" the tumor intact. Shortening treatment time can lead to tissue residue. These factors restrict the further development of HIFU technology. Based on the physical characteristics of ultrasound, such as reflection and refraction, this paper proposes a cap ablation method to improve the ablation methodology, which promotes the ultrasonic energy to gather into the cap structure with two sides of mutually formed angles. Reducing the diffusion of energy to the surrounding normal tissue and reducing the excessive overlap of internal energy, thus reducing energy waste and enhancing HIFU therapy. Objective: to explore the feasibility of HIFU hat ablation in both in vitro and in vivo experiments. To compare the ablation effect of cap ablation with different parameters, to find the best ablation method and to enhance HIFU treatment. Materials and methods: the experiment was divided into two parts: bovine liver in vitro and rabbit liver in vivo. In vitro, the angle between the two irradiated surfaces was changed. The coagulation necrosis was obtained in different parameter combinations. The ablation effect of the two ablation models was compared with that of the traditional ablation model. The conclusions were applied to the living rabbit liver. After ablation, the liver tissue was sectioned and stained with TTC, and the coagulative necrosis was observed, the volume of coagulation necrosis and the energy efficiency factor were calculated. Results: in vitro and in vivo experiments, coagulation necrosis was observed in the naked eye and in vivo. The necrotic volume was much larger than that of the irradiated area, and there was significant difference in the morphology of the coagulant necrosis after changing the angle of irradiation. However, there was no significant difference in coagulation necrosis volume between different irradiation sequences. Under certain conditions, the cap ablation mode could shorten the ablation time and reduce the total energy expenditure compared with the traditional ablation mode. Conclusion: cap ablation is feasible in both in vitro and in vivo. At the same time, cap ablation is more efficient than traditional ablation under certain conditions.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R730.5;R454.3

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