本文選題：超聲熱療 + 生物熱傳導(dǎo)方程��； 參考：《陜西師范大學(xué)》2007年碩士論文

【摘要】： 根據(jù)WHO預(yù)測(cè)：惡性腫瘤將成為21世紀(jì)危害人類(lèi)健康的頭號(hào)殺手。但就目前情況而言，對(duì)于一些腫瘤特別是中晚期腫瘤，任何一種常規(guī)治療(手術(shù)切除、化學(xué)療法或放射療法)均不能單獨(dú)成為一種根治腫瘤的手段。腫瘤溫?zé)嶂委熓峭ㄟ^(guò)超聲加熱腫瘤組織而促進(jìn)腫瘤細(xì)胞的死亡。高強(qiáng)度聚焦超聲技術(shù)則是近幾年快速發(fā)展的先進(jìn)熱療技術(shù)，它能將超聲波聚焦于深部腫瘤組織，通過(guò)高熱效應(yīng)使腫瘤組織在短時(shí)間內(nèi)凝固壞死，而對(duì)超聲波所穿過(guò)的組織和靶區(qū)周?chē)恼＝M織沒(méi)有損傷。高強(qiáng)度聚焦超聲技術(shù)作為一種有效的和非侵入性的腫瘤治療方法已開(kāi)始引起腫瘤熱療領(lǐng)域的關(guān)注。 然而，，隨著對(duì)高強(qiáng)度聚焦超聲技術(shù)研究的不斷深入，發(fā)現(xiàn)在超聲熱療的過(guò)程中，關(guān)于如何提高超聲熱療的治愈成功率和治療效率的相關(guān)理論還不成熟。這方面的問(wèn)題涉及：治療靶區(qū)解剖位置和幾何形狀的確定、治療熱劑量的確定、最佳聲焦點(diǎn)分布或最佳掃描路線和掃描速度選取、治療區(qū)域溫度分布計(jì)算、熱區(qū)計(jì)算結(jié)果與預(yù)定加熱指標(biāo)的比較和加熱方法的優(yōu)化。因此，要完善超聲加熱治療的理論，還需做大量的研究、探索工作。 本文通過(guò)數(shù)值模擬的方法，探討了超聲熱療時(shí)，影響生物軟組織內(nèi)熱源與溫度分布的因素。主要工作和相關(guān)結(jié)論如下所示： (1)闡述了超聲熱療技術(shù)的基本原理，以高強(qiáng)度聚焦超聲技術(shù)為例，詳細(xì)介紹了聚焦超聲對(duì)處于其聲場(chǎng)中的物質(zhì)的作用機(jī)理，并歸納總結(jié)了幾種常見(jiàn)的醫(yī)用聚焦聲場(chǎng)； (2)對(duì)比了幾種生物熱傳導(dǎo)模型，得出Pennes生物熱傳導(dǎo)模型是目前比較理想的模型。并以該模型為基礎(chǔ)，運(yùn)用Matlab數(shù)學(xué)工具，討論了對(duì)于同一生物軟組織，在被聚焦超聲加熱時(shí)，其內(nèi)部的熱源分布由下列參數(shù)決定：聲源頻率f、換能器曲率半徑R及孔徑半徑a。數(shù)值模擬結(jié)果顯示：聚焦聲場(chǎng)中的生物組織內(nèi)熱源的分布區(qū)域隨著超聲頻率的增高、換能器孔徑半徑的增加、換能器曲率半徑的減小而不斷變小。 (3)分析了聲源參數(shù)和生物組織參數(shù)對(duì)組織溫度分布的影響。運(yùn)用Matlab的pdetool工具，求解了Pennes生物熱傳導(dǎo)方程，得到的結(jié)論是： a．聲源參數(shù)對(duì)生物組織溫升的影響 換能器曲率半徑越小、孔徑半徑越大、超聲頻率越高時(shí)，組織內(nèi)溫度上升越快、越多。幾何焦距及換能器半徑對(duì)升溫快慢及大小的影響很突出；超聲頻率越高時(shí)，因?yàn)樗p作用，聲焦點(diǎn)處的升溫快慢及大小隨頻率變化較小。 b．生物組織特性參數(shù)對(duì)組織溫升的影響 衰減系數(shù)越大、熱傳導(dǎo)系數(shù)越小時(shí)，組織內(nèi)溫度上升越快。當(dāng)衰減系數(shù)較大時(shí)，衰減系數(shù)的變化對(duì)聲焦點(diǎn)處溫升快慢和大小的影響相對(duì)較��；熱傳導(dǎo)系數(shù)較大時(shí)，溫度上升較小，但達(dá)到穩(wěn)態(tài)溫度所需的加熱時(shí)間也越短。
[Abstract]:According to WHO forecast: malignant tumor will become the first killer of human health in the 21 st century. However, as far as the present situation is concerned, no conventional therapy (surgical resection, chemotherapy or radiotherapy) can be used to cure the tumor alone for some tumors, especially in the middle and late stage. Tumor hyperthermia therapy promotes tumor cell death by ultrasound heating of tumor tissue. High intensity focused ultrasound (HIFU) is an advanced hyperthermia technique developed rapidly in recent years. It can focus ultrasound on deep tumor tissue and make tumor tissue coagulate and necrosis in a short time by high heat effect. There was no damage to the tissue through which the ultrasound went and the normal tissue around the target area. As an effective and non-invasive tumor therapy, high intensity focused ultrasound (HIFU) has attracted more and more attention in the field of hyperthermia. However, with the development of high intensity focused ultrasound (HIFU), it is found that in the process of ultrasonic hyperthermia, the theory on how to improve the cure success rate and therapeutic efficiency of ultrasonic hyperthermia is not mature. The problems related to the determination of the anatomical position and geometric shape of the therapeutic target, the determination of the therapeutic heat dose, the optimal acoustic focus distribution or the optimal scanning route and scanning speed, the calculation of the temperature distribution in the treatment area, The comparison between the calculated results of the hot zone and the predetermined heating index and the optimization of the heating method. Therefore, in order to perfect the theory of ultrasonic heating, a lot of research and exploration are needed. In this paper, the factors that influence the distribution of heat source and temperature in biological soft tissue during ultrasonic hyperthermia are discussed by numerical simulation. The main work and related conclusions are as follows: (1) the basic principle of ultrasonic hyperthermia is expounded. In this paper, the mechanism of focused ultrasound on substances in its sound field is introduced in detail, and several common medical focused sound fields are summarized. (2) several biological heat conduction models are compared. Pennes biological heat conduction model is an ideal model at present. On the basis of this model, the distribution of internal heat source is determined by the following parameters: the frequency of sound source f, the radius of curvature of transducer R and the radius of aperture a for the same biological soft tissue by using Matlab mathematical tools. The distribution of heat source is determined by the following parameters: the frequency of sound source f, the radius of curvature of transducer R and the radius of aperture a. The numerical simulation results show that the distribution of heat source in the biological tissue in the focused sound field increases with the increase of ultrasonic frequency, and the aperture radius of the transducer increases. The curvature radius of transducer becomes smaller and smaller. (3) the influence of sound source parameters and biological tissue parameters on tissue temperature distribution is analyzed. The Pennes biothermic conduction equation is solved by using the pdetool tool of Matlab. The results are as follows: a. The influence of sound source parameters on temperature rise of biological tissue. The smaller the curvature radius of transducer, the larger the aperture radius. The higher the frequency of ultrasound, the faster and more the temperature in the tissue rises. The effect of geometric focal length and transducer radius on the speed and size of temperature rise is very prominent; the higher the ultrasonic frequency, the more attenuation, The rate and magnitude of the temperature rise at the acoustic focus are smaller with the frequency. B. the larger the attenuation coefficient of the effect of biological tissue characteristic parameters on the temperature rise of the tissue, The smaller the heat conductivity is, the faster the temperature in the tissue rises. When the attenuation coefficient is larger, the change of attenuation coefficient has a relatively small effect on the temperature rise rate and magnitude at the acoustic focal point, and when the heat conduction coefficient is larger, the temperature rise is smaller, but the heating time required to reach the steady state temperature is also shorter.
【學(xué)位授予單位】：陜西師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2007
【分類(lèi)號(hào)】：R312

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 羅環(huán)千;超聲空化阻斷兔正常肝臟血流對(duì)超聲熱療的促進(jìn)作用[D];廣州醫(yī)學(xué)院;2010年

本文編號(hào)：2080640