高強度聚焦超聲聲場的時域有限差分法仿真研究
發(fā)布時間：2018-11-06 20:45
【摘要】：目的：高強度聚焦超聲(High-intensity Focused Ultrasound, HIFU)治療技術(shù)具有非侵入性、微創(chuàng)傷等優(yōu)點,已成為眾多研究者關(guān)注和研究的熱點,并應(yīng)用于體外沖擊波碎石療法(Extracorporeal shock wave lithotripisy, ESWL)、HIFU腫瘤治療等臨床治療之中。但這些治療中都有可能引發(fā)并發(fā)癥,如體外沖擊波碎石治療中可能出現(xiàn)尿血、腎血腫、腎破裂等,HIFU腫瘤治療中可能引起皮膚燒傷、神經(jīng)損傷等對人體正常組織的傷害。影響HIFU療法療效和引發(fā)這些并發(fā)癥的主要因素之一為高強度超聲波聚焦傳播過程中,在人體內(nèi)形成的焦點區(qū)域位置、形狀、大小、聲壓分布和焦點前淺層區(qū)域能量分布。研究HIFU治療中形成的焦點區(qū)域、能量密度分布及人體組織對焦點區(qū)域聲壓、實際形成焦點位置的影響,為ESWL治療計劃的制定提供理論依據(jù)；研究降低焦點前非靶區(qū)能量密度和提高聚焦效率的聚焦方法,為目前ESWL治療、HIFU腫瘤治療中對人體正常組織傷害的解決提供新途徑和方法。 方法：森田長吉等人提出了時域有限差分(Finite Difference Time Domain, FDTD)超聲波非線性傳播的仿真方法,并以Reichenberger的ESWL水中實驗為例,對水體內(nèi)高強度超聲波非線性傳播進行了仿真研究,得到了與實驗測得波形完全一致的仿真結(jié)果。 本論文利用森田長吉等人提出的高強度超聲波非線性傳播的FDTD仿真方法,以Reichenberger的ESWL水中實驗為例,(1)參照實際人體組織結(jié)構(gòu)建立單一人體組織和復合人體組織仿真模型,研究ESWL治療過程中超聲波在人體組織內(nèi)非線性傳播特性和人體組織對超聲波聚焦傳播所形成的焦點區(qū)域位置、大小、形狀、聲壓分布影響。(2)研究解決ESWL治療和HIFU腫瘤治療過程中并發(fā)癥問題,應(yīng)用FDTD仿真的方法,研究并提出一種可以減小淺層區(qū)域能量密度和提高超聲能量向焦點聚焦效果的新型相位控制圓環(huán)狀聚焦方法。結(jié)果：1.以Reichenberger的ESWL水中實驗為例,建立水體仿真模型進行仿真,仿真得到ESWL治療中在三維空間上所形成的焦點區(qū)域近似為橄欖球體,但其所形成的焦距(最大聲壓位置)與設(shè)備的幾何焦距并不一致。 2.在Reichenberger水體實驗仿真模型的基礎(chǔ)上,加一定厚度人體脂肪或肌肉組織建立仿真模型,討論不同厚度的不同人體組織對所形成焦點區(qū)域、最大聲壓、焦距的影響。仿真結(jié)果表明,最大聲壓隨脂肪厚度增厚而增大,隨肌肉增厚而減小；焦距隨人體脂肪和肌肉厚度增加而減小；形成的橄欖球體狀焦點區(qū)域的長、短軸長度隨脂肪厚度的增厚變小,隨肌肉厚度增厚長軸增大,短軸變化不大。 3.參照ESWL臨床治療時B超圖像顯示的人體結(jié)構(gòu)層次及厚度,建立包括皮下脂肪、肌肉、腎周脂肪、腎臟的復合人體組織仿真模型,數(shù)值仿真ESWL治療過程中超聲波非線性傳播過程。仿真結(jié)果為焦距為118.94mm,其值小于幾何焦距120mm,最大聲壓34.19MPa,其值小于水中實測聲壓44.56MPa。 4.提出新型相位控制環(huán)狀聚焦方法,其FDTD方法數(shù)值仿真結(jié)果表明,在陣列陣元相同條件下,圓環(huán)聚集法在焦點處獲得的最大能量密度比相控點聚焦法高大約30%,但焦點前的非靶區(qū)域的最大能量密度相同；如在焦點處獲得的最大能量密度相同的條件下,圓環(huán)聚集法在焦點前的斷面上的最大能量密度比點聚焦下降大約10%。 結(jié)論：本論文的仿真研究是以Reichenberger水中實驗為例建立水體模型和含有人體組織的模型,利用FDTD法數(shù)值仿真法研究了高強度聚焦超聲治療過程中的所形成焦點區(qū)域以及最大聲壓、焦點位置,焦點區(qū)域的大小以及隨人體組織厚度變化的規(guī)律,為ESWL臨床治療計劃的制定提供理論依據(jù)；同時提出了一種可以降低焦點前非靶區(qū)能量密度和提高聚焦效率的圓環(huán)狀聚焦方法,改聚焦方法的提出為目前ESWL治療、HIFU腫瘤治療中對人體正常組織傷害的解決提供新途徑和方法。本研究建立的仿真模型,僅以規(guī)則無方向性差異組織的設(shè)定條件下進行仿真研究,與實際人體組織結(jié)構(gòu)、組織的特性仍有一定差異,實際人體組織結(jié)構(gòu)、組織特性的三維模型有待進一步仿真研究。
[Abstract]:Objective: The high-intensity focused ultrasound (HIFU) treatment technology has the advantages of non-invasive, microtrauma and so on. It has become the focus of many researchers' attention and research, and is applied to the clinical treatment of extracorporeal shock wave lithotripsy (ESWL) and HIFU tumor treatment. However, there are possible complications in these treatment, such as the possibility of urine blood, renal hematoma, and kidney rupture in the treatment of extracorporeal shock wave lithotripsy. In the treatment of HIFU tumor, the injury to the normal tissues of the human body can be caused by skin burn, nerve injury and the like. The focus area, shape, size, sound pressure distribution and the energy distribution of the shallow area in the focal area, which are formed in the human body, are the main factors that affect the curative effect of the HIFU therapy and the complications. The focus area, energy density distribution and the influence of human body tissue on the focal area sound pressure and the actual focus position were studied in the study of HIFU treatment, and the theoretical basis for the development of the ESWL treatment plan was provided. The focus of the energy density and the focusing efficiency of the non-target area before the focus was studied. The invention provides a new way and a method for solving the normal tissue injury of the human body in the treatment of the ESWL and the treatment of the HIFU tumor. Methods: The finite difference time domain (FDTD) method for nonlinear propagation of the time domain was proposed, and the nonlinear propagation of high-intensity ultrasonic waves in water was simulated with the experiment of Reichenberger's ESWL water. The simulation of the waveform is obtained in the same way as the measured waveform. The results of this paper are as follows: (1) To establish a single body tissue and a compound body group with reference to the actual human tissue structure, using the high-intensity ultrasonic non-linear propagation (FDTD) simulation method proposed by the son Tian Changji, et al., in the case of Reichenberger's ESWL water experiment. In the study of the non-linear propagation characteristics of the ultrasound in the human tissue and the focal region position, size, shape, sound, Effect of pressure distribution. (2) To study the problems of complications during the treatment of ESWL and HIFU, the method of FDTD simulation is applied to study and propose a new phase control ring which can reduce the energy density of the shallow region and improve the focusing effect of ultrasonic energy to the focus. shape-focusing method The results are as follows: 1. The simulation of the water body simulation model is carried out in the ESWL water experiment of Reichenberger, and the focal area formed in the three-dimensional space of the ESWL treatment is approximated as a football body, but the focal length (the maximum sound pressure position) and the geometric focus of the device are obtained. 2. Based on the experimental simulation model of the Reichenberger water body, a simulation model of human body fat or muscle tissue with a certain thickness is added, and different human body tissues with different thicknesses are used for forming the focal area, and the maximum The simulation results show that the maximum sound pressure increases with the thickness of the fat and decreases with the thickening of the muscle; the focal length decreases with the increase of the body fat and the thickness of the muscle; the length of the formed football body-shaped focal area and the length of the short axis vary with the fat The thickening of the thickness of the skin becomes small, and the long axis is increased with the thickness of the muscle. The change of the short axis is not great. 3. With reference to the structure level and thickness of the human body displayed by the B-ultrasound image in the clinical treatment of ESWL, the complex human tissue simulation model including the subcutaneous fat, the muscle, the kidney and the fat and the kidney is established, and the numerical simulation ESWL treatment process The simulation result is that the focal length is 118.94mm, its value is less than 120mm of the geometric focal length and the maximum sound pressure is 340.19MPa, its value is less than that of the water A new phase-controlled cyclic focusing method is proposed. The numerical simulation results of FDTD method show that the maximum energy density obtained at the focal point is the same as the array element. The degree of focus is about 30% higher than the phase control point focus method, but the maximum energy density of the non-target area before the focus is the same; if the maximum energy density obtained at the focal point is the same, the maximum energy of the ring aggregation method on the section before the focus Conclusion: The simulation of this paper is to establish a water body model and a model containing human tissue in Reichenberger's water experiment. The numerical simulation of this paper is used to study the effect of high intensity focused ultrasound in the treatment of high intensity focused ultrasound. The focal area and the maximum sound pressure, the focal position, the size of the focal area and the change of the thickness of the tissue of the human body are formed, and the theoretical basis for the development of the ESWL clinical treatment plan is provided. At the same time, the energy of the non-target area before the focus can be reduced The invention relates to an annular focusing method for improving the density and improving the focusing efficiency, A new approach and a method for solving the problem of normal tissue injury are provided. The simulation model established in the study is only simulated under the set conditions of the regular non-directional difference organization, and the structure of the actual human body and the characteristics of the tissue still have a certain difference, and the actual human body structure and the group
【學位授予單位】：天津醫(yī)科大學
【學位級別】：碩士
【學位授予年份】：2007
【分類號】：R312
本文編號：2315421
[Abstract]:Objective: The high-intensity focused ultrasound (HIFU) treatment technology has the advantages of non-invasive, microtrauma and so on. It has become the focus of many researchers' attention and research, and is applied to the clinical treatment of extracorporeal shock wave lithotripsy (ESWL) and HIFU tumor treatment. However, there are possible complications in these treatment, such as the possibility of urine blood, renal hematoma, and kidney rupture in the treatment of extracorporeal shock wave lithotripsy. In the treatment of HIFU tumor, the injury to the normal tissues of the human body can be caused by skin burn, nerve injury and the like. The focus area, shape, size, sound pressure distribution and the energy distribution of the shallow area in the focal area, which are formed in the human body, are the main factors that affect the curative effect of the HIFU therapy and the complications. The focus area, energy density distribution and the influence of human body tissue on the focal area sound pressure and the actual focus position were studied in the study of HIFU treatment, and the theoretical basis for the development of the ESWL treatment plan was provided. The focus of the energy density and the focusing efficiency of the non-target area before the focus was studied. The invention provides a new way and a method for solving the normal tissue injury of the human body in the treatment of the ESWL and the treatment of the HIFU tumor. Methods: The finite difference time domain (FDTD) method for nonlinear propagation of the time domain was proposed, and the nonlinear propagation of high-intensity ultrasonic waves in water was simulated with the experiment of Reichenberger's ESWL water. The simulation of the waveform is obtained in the same way as the measured waveform. The results of this paper are as follows: (1) To establish a single body tissue and a compound body group with reference to the actual human tissue structure, using the high-intensity ultrasonic non-linear propagation (FDTD) simulation method proposed by the son Tian Changji, et al., in the case of Reichenberger's ESWL water experiment. In the study of the non-linear propagation characteristics of the ultrasound in the human tissue and the focal region position, size, shape, sound, Effect of pressure distribution. (2) To study the problems of complications during the treatment of ESWL and HIFU, the method of FDTD simulation is applied to study and propose a new phase control ring which can reduce the energy density of the shallow region and improve the focusing effect of ultrasonic energy to the focus. shape-focusing method The results are as follows: 1. The simulation of the water body simulation model is carried out in the ESWL water experiment of Reichenberger, and the focal area formed in the three-dimensional space of the ESWL treatment is approximated as a football body, but the focal length (the maximum sound pressure position) and the geometric focus of the device are obtained. 2. Based on the experimental simulation model of the Reichenberger water body, a simulation model of human body fat or muscle tissue with a certain thickness is added, and different human body tissues with different thicknesses are used for forming the focal area, and the maximum The simulation results show that the maximum sound pressure increases with the thickness of the fat and decreases with the thickening of the muscle; the focal length decreases with the increase of the body fat and the thickness of the muscle; the length of the formed football body-shaped focal area and the length of the short axis vary with the fat The thickening of the thickness of the skin becomes small, and the long axis is increased with the thickness of the muscle. The change of the short axis is not great. 3. With reference to the structure level and thickness of the human body displayed by the B-ultrasound image in the clinical treatment of ESWL, the complex human tissue simulation model including the subcutaneous fat, the muscle, the kidney and the fat and the kidney is established, and the numerical simulation ESWL treatment process The simulation result is that the focal length is 118.94mm, its value is less than 120mm of the geometric focal length and the maximum sound pressure is 340.19MPa, its value is less than that of the water A new phase-controlled cyclic focusing method is proposed. The numerical simulation results of FDTD method show that the maximum energy density obtained at the focal point is the same as the array element. The degree of focus is about 30% higher than the phase control point focus method, but the maximum energy density of the non-target area before the focus is the same; if the maximum energy density obtained at the focal point is the same, the maximum energy of the ring aggregation method on the section before the focus Conclusion: The simulation of this paper is to establish a water body model and a model containing human tissue in Reichenberger's water experiment. The numerical simulation of this paper is used to study the effect of high intensity focused ultrasound in the treatment of high intensity focused ultrasound. The focal area and the maximum sound pressure, the focal position, the size of the focal area and the change of the thickness of the tissue of the human body are formed, and the theoretical basis for the development of the ESWL clinical treatment plan is provided. At the same time, the energy of the non-target area before the focus can be reduced The invention relates to an annular focusing method for improving the density and improving the focusing efficiency, A new approach and a method for solving the problem of normal tissue injury are provided. The simulation model established in the study is only simulated under the set conditions of the regular non-directional difference organization, and the structure of the actual human body and the characteristics of the tissue still have a certain difference, and the actual human body structure and the group
【學位授予單位】：天津醫(yī)科大學
【學位級別】：碩士
【學位授予年份】：2007
【分類號】：R312
【引證文獻】
相關(guān)碩士學位論文 前1條
1 張煥春;基于FDTD的黏熱流體介質(zhì)中超聲波傳播數(shù)值仿真[D];青島大學;2012年
，本文編號：2315421
本文鏈接：http://sikaile.net/yixuelunwen/binglixuelunwen/2315421.html
最近更新
教材專著
