南京大学学报(自然科学版) ›› 2017, Vol. 53 ›› Issue (1): 114.
戚 萌,王 鑫,刘晓宙*
Qi Meng,Wang Xin,Liu Xiaozhou*
摘要: 高强度聚焦超声(HIFU)是现代医学肿瘤治疗物理疗法的一项重要技术,其原理是通过聚焦方法将大面积超声聚焦换能器辐射出的声能量汇聚于面积极小的聚焦区,使聚焦区获得较强的声能量并利用超声波的热效应在短时间内使病灶部位获得较高的温升,从而使肿瘤组织热凝固坏死.大张角聚焦换能器指的是球面半张角大于16.6°的球壳式聚焦换能器.相对于传统的小张角换能器,大张角聚焦换能器拥有更强的声聚焦效应,聚焦区半径更小,穿透性更好,声能量聚焦效果明显强于小张角换能器,所以可以获得更好的温升.利用Spheroidal Beam Equation(SBE)方程求解大张角聚焦换能器条件下的声场获得空间热源的产热率,然后通过Pennes方程解出大张角聚焦换能器条件下生物组织中的温度场分布.研究不同改变张角方式下大张角聚焦换能器作用下生物组织的温升分布情况,研究结果表明改变换能器的孔径以改变张角时,张角越大温升越大,而改变其焦距以改变张角时,温度变化则相反.实验也验证了换能器孔径变化对生物组织中的温升的影响.
[1]FRANK J. Precision high intensity focusing ultrasonic machines for surgery. American Journal of Physical Medicine & Rehabilitation, 1958. 37(3): p. 152. [2]Yoshizawa S. High intensity focused ultrasound lithotripsy with cavitating microbubbles. Medical and Biological Engineering and Computing, 2009. 47(8): 851-860. [3]Diederich C J, Hynynen K. Ultrasound technology for hyperthermia. Ultrasound in Medicine & Biology, 1999. 25(6): p. 871-887. [4]Kamakura T, Ishiwata T, Matsuda K. A new theoretical approach to the analysis of nonlinear sound beams using the oblate spheroidal coordinate system. Journal of the Acoustical Society of America, 1999. 105(6): p. 3083-3086. [5]Kamakura T, Ishiwata T, Matsuda K. Model equation for strongly focused finite -amplitude sound beams. Journal of the Acoustical Society of America, 2000. 107(6): p. 3035-3046. [6]Li J L, Liu X Z, Zhang D, et al. Influence of ribs on the Nonlinear sound field of therapeutic ultrasound. Ultrasound in Medicine & Biology, 2007. 33(9): p. 1413-1420. [7]Liu X Z, Yin C, Gong X F, et al. Theoretical and experimental study on temperature elevation behind ribs caused by weakly focused ultrasound. Ultrasound in Medicine & Biology, 2010. 36(10): p. 1704-1712. [8]Lin J X, Liu X Z, Gong X F, et al. Computational Study on the propagation of strongly focused nonlinear ultrasound in tissue with rib-like structures. Journal of the Acoustical Society of America, 2013. 134(2): p. 1702–1714. [9]Fan T B, Liu Z B, Zhang D, et al. Comparative study of lesions created by high intensity focused ultrasound using sequential discrete and continuous scanning strategies. IEEE transactions on bio-medical engineering, 2011. 10: 763-769. [10]Qian S, Hu J. Research on nonlinear effects of sound fields induced by self-focused concave spherical transducers. Piezoelectectrics & Acoustooptics, 2007. 29(6): 720-722. [11]Tjøtta J N, Tjøtta S. Model equation and boundary condi tions for the sound field from a high frequency,strongly curved and highly intense transducer. Acta Acustica, 1993, 1: 69-87. [12]Li F Q, Gong X B, Hu K, et al. Effect of ribs in high intensity focused ultrasound beam path on formation of coagulative necrosis in goat liver. Chinese Journal of Ultrasonography, 2006, 15: 943. [13]Xia R, Shou W, Cheng G, et al. The further study of the spheroidal beam equation for focused finite-amplitude sound beams. Journal of Computational Acoustics, 2003, 11(1): 47-54. [14]Lucas B G, Muir T G. The field of a focusing source. The Journal of the Acoustical Society of America, 1982, 72(4): 1289-1296. [15]Pennes H H. Analysis of tissue and arterial blood temperatures in the resting human forearm. Journal of Applied Physiology, 1948, 11(2): 93-122. [16]El-Mikkawy M. A generalized symbolic Thomas algorithm. Applied Mathematics, 2012, 3(4): 342. [17]Wang X, Lin J X, Liu X Z, et al. Study of the temperature rise induced by a focusing transducer with a wide aperture angle on biological tissue containing ribs. Chinese Physics B, 2016, 25(4): 044301. |
No related articles found! |
|