本文選題：熱療 + 有限元��； 參考：《上海交通大學(xué)》2008年碩士論文

【摘要】： 腫瘤熱療是目前腫瘤治療的研究重點(diǎn),已成為繼手術(shù)、放療、化療之后又一重要的治癌手段。在熱療臨床應(yīng)用中,影響療效的因素很多,如系統(tǒng)的功率、加熱時(shí)間、作用方式以及組織的物性參數(shù)等,在制定治療計(jì)劃時(shí)需綜合考慮這些因素。熱療分為無(wú)創(chuàng)和微創(chuàng)兩種。前者以高強(qiáng)度聚焦超聲技術(shù)為代表,后者以射頻消融系統(tǒng)為代表。文中分別對(duì)這兩個(gè)典型的熱療系統(tǒng)圍繞上述因素展開(kāi)了分析。 針對(duì)無(wú)創(chuàng)熱療——高強(qiáng)度聚焦超聲技術(shù),主要關(guān)注系統(tǒng)參數(shù)(主要指聚焦超聲能量)對(duì)加熱效果的影響,研究了聚焦超聲劑量與損傷區(qū)域的關(guān)系。結(jié)果表明:為得到大小和形狀相似的熱損傷焦域,聚焦超聲的聲場(chǎng)強(qiáng)度和加熱時(shí)間近似滿(mǎn)足關(guān)系:It0.8=常數(shù)。利用公式可以進(jìn)行不同聲強(qiáng)、時(shí)間治療方案之間的切換。另外,針對(duì)單焦點(diǎn)掃描情況,探討了掃描間距對(duì)溫度場(chǎng)分布的影響:當(dāng)焦點(diǎn)間距為一倍的焦斑直徑時(shí),焦點(diǎn)處最高溫度的增長(zhǎng)率都在7%以上;隨著掃描間距的增大,前面焦點(diǎn)的熱場(chǎng)對(duì)后續(xù)焦點(diǎn)的影響變?nèi)�。因此在掃描過(guò)程中,要衡量選擇合適的掃描間距,并及時(shí)調(diào)整治療參數(shù),避免出現(xiàn)過(guò)高溫度。 針對(duì)微創(chuàng)熱療——射頻消融系統(tǒng),建立電熱耦合有限元模型,側(cè)重討論了整個(gè)加熱過(guò)程中,血液灌流、水冷溫度等參數(shù)對(duì)熱損傷的影響。得出:在水冷作用下,組織的最高溫度區(qū)位于電極表面2-3mm的地方;水冷溫度越低,得到的消融范圍越大。當(dāng)組織的血液灌流率從0變化到3.0e-3(1/s),熱損傷直徑縮小了33.8%,數(shù)據(jù)表明血液灌流率對(duì)于溫度和熱損傷體積的影響很大。文中還對(duì)兩種確定熱損傷邊界(50℃和EM43)的方法進(jìn)行了比較,探討了它們之間的區(qū)別。 通過(guò)對(duì)這兩種熱療系統(tǒng)的分析,建立了一套適用于兩種熱療方式熱場(chǎng)分布研究的方法,從不同角度分析了各參數(shù)對(duì)熱療的影響,期望能推動(dòng)和推廣熱療技術(shù)的應(yīng)用。
[Abstract]:Tumor hyperthermia is the focus of cancer treatment, and has become an important means of cancer treatment after surgery, radiotherapy and chemotherapy. In the clinical application of hyperthermia, there are many factors that affect the curative effect, such as the power of the system, heating time, the mode of action and the physical parameters of the tissue. These factors should be taken into account when making the treatment plan. Hyperthermia is divided into two types: non-invasive and minimally invasive. The former is represented by high intensity focused ultrasound and the latter by radiofrequency ablation system. In this paper, the two typical hyperthermia systems are analyzed around the above factors. For the non-invasive hyperthermal-high intensity focused ultrasound (HIFU) technology, the influence of system parameters (mainly focused ultrasound energy) on the heating effect is mainly concerned. The relationship between the dose of focused ultrasound and the damage area was studied. The results show that in order to obtain the thermal damage focal region of similar size and shape, the sound field intensity and heating time of focused ultrasound approximately satisfy the relation of: I t 0.8 = constant. The formula can be used to switch between different sound intensity and time therapy. In addition, the effect of scanning spacing on the temperature field distribution is discussed. When the focal spot diameter is double, the growth rate of the highest temperature at the focal point is above 7%, and with the increase of the scanning distance, The effect of the thermal field of the front focus on the subsequent focus becomes weaker. Therefore, in the process of scanning, we should measure the appropriate scanning distance and adjust the treatment parameters in time to avoid excessive temperature. For the minimally invasive hyperthermia radiofrequency ablation system, an electrothermal coupled finite element model is established. The effects of the parameters such as hemoperfusion and water cooling temperature on the thermal damage during the whole heating process are emphatically discussed. It is concluded that the highest temperature region of the tissue is located at the 2-3mm on the electrode surface under water cooling, and the lower the water cooling temperature is, the larger the ablation range is. When the hemoperfusion rate of the tissue changed from 0 to 3. 0e-3 / s-1 / s, the diameter of the heat injury decreased by 33. 8%. The data showed that the hemoperfusion rate had a great influence on the temperature and the volume of the thermal injury. Two methods for determining thermal damage boundary (50 鈩，

本文編號(hào)：1999777