【摘要】：研究背景 目前，高強(qiáng)度聚焦超聲（high intensity focused ultrasound，HIFU）治療技術(shù)在臨床上的應(yīng)用是對(duì)病灶進(jìn)行高功率的連續(xù)波輻照，利用其熱效應(yīng)對(duì)靶組織進(jìn)行消融治療。脈沖高強(qiáng)度聚集超聲（pulsed highintensity focused ultrasound，PHIFU）與現(xiàn)有的HIFU發(fā)射連續(xù)波消融組織不同，其治療方式是脈沖式，由脈沖輻照時(shí)間和間歇時(shí)間組成。前期實(shí)驗(yàn)研究發(fā)現(xiàn)PHIFU能夠產(chǎn)生明顯的空化效應(yīng)，引起靶區(qū)組織損傷。 PHIFU作為一種間歇輻照方式，可能會(huì)減少連續(xù)波輻照對(duì)靶區(qū)聲通道上因能量沉積而產(chǎn)生的正常組織損傷。作為一種潛在的新治療模式，PHIFU消融腫瘤的組織學(xué)變化及其靶區(qū)超聲影像學(xué)特征，血流速度對(duì)PHIFU消融效果的影響是臨床應(yīng)用該治療模式前的一個(gè)重要研究?jī)?nèi)容。本課題應(yīng)用臨床HIFU腫瘤治療設(shè)備，擬在離體豬肝灌注模型上，通過調(diào)節(jié)肝灌注流量來觀察PHIFU消融肝組織的凝固性壞死體積變化和B超聲像圖特征，以及肝血管對(duì)PHIFU消融效果的作用，探討血流速度和血管對(duì)PHIFU消融肝組織的影響及其靶區(qū)超聲影像學(xué)變化，為HIFU臨床應(yīng)用提供新的治療模式和參數(shù)。 目的 1.探討血流速度對(duì)PHIFU消融肝組織的影響及其靶區(qū)超聲影像學(xué)變化。 2.探討血管對(duì)PHIFU消融肝組織的影響和血管的損傷變化。 方法 1.不同肝灌注流量下PHIFU消融肝組織的特征及其超聲影像圖變化 實(shí)驗(yàn)動(dòng)物:豬肝由屠宰場(chǎng)提供，家豬被處死后2～3min內(nèi)取出肝臟，建立經(jīng)門靜脈、肝動(dòng)脈和下腔靜脈進(jìn)行灌流的離體豬肝灌注模型，達(dá)到灌注要求后待用。 實(shí)驗(yàn)方法 （1）以連續(xù)波HIFU輻照為對(duì)照組，PHIFU輻照為實(shí)驗(yàn)組。輻照參數(shù)設(shè)定：脈沖重復(fù)頻率100Hz，輻照功率80W，深度20mm。實(shí)驗(yàn)組占空比20%，，輻照時(shí)間25s，對(duì)照組占空比100%，輻照時(shí)間10s。通過調(diào)整體外循環(huán)機(jī)中門靜脈轉(zhuǎn)流泵的轉(zhuǎn)速，使門靜脈的流量分別為442mL/min、588mL/min、746mL/min、886mL/min。 （2）在不同灌注流量下，應(yīng)用PHIFU定點(diǎn)輻照離體灌注肝臟。實(shí)驗(yàn)組在輻照過程中應(yīng)用B超實(shí)時(shí)觀察靶區(qū)聲像圖變化，分析靶區(qū)灰度變化的規(guī)律，每組實(shí)驗(yàn)重復(fù)20次。 （3）PHIFU輻照后，切開灌注肝組織，找到靶區(qū)組織最大的損傷面，測(cè)量并記錄壞死區(qū)域的損傷情況，計(jì)算凝固性壞死體積，局部取材，觀察靶區(qū)的組織學(xué)變化。 2.肝血管對(duì)PHIFU消融肝組織的影響 實(shí)驗(yàn)方法： (1)采用HIFU脈沖波（實(shí)驗(yàn)組）和連續(xù)波（對(duì)照組）兩種輻照方式，輻照參數(shù)分別為聲功率80W、占空比20%、輻照時(shí)間50s和聲功率80W、占空比100%、輻照時(shí)間10s，輻照深度為40mm，脈沖重復(fù)頻率為100Hz。 （2）通過HIFU機(jī)載超聲尋找適合的治療層面，找到管徑為4mm左右的血管，分別將血管、距離血管前、后方3mm處的肝組織定位為靶區(qū)，采用定點(diǎn)輻照靶區(qū)肝臟，每組實(shí)驗(yàn)重復(fù)15次。 （3）輻照后切開肝組織，找到靶區(qū)最大的損傷面，測(cè)量并記錄壞死區(qū)域，計(jì)算凝固性壞死體積，肉眼觀察兩組靶區(qū)肝組織和血管的損傷情況，分別取材，觀察組織學(xué)變化。 結(jié)果： 1. PHIFU消融肝組織的損傷特點(diǎn)：與連續(xù)波HIFU輻照相同，PHIFU組靶區(qū)肝組織均出現(xiàn)凝固性壞死的特征性變化，損傷區(qū)和非損傷區(qū)邊緣清晰，損傷區(qū)內(nèi)未發(fā)現(xiàn)有明顯的空洞形成。 2. PHIFU消融肝組織的超聲影像學(xué)變化：PHIFU輻照離體灌注肝臟時(shí)，B超能實(shí)時(shí)顯示靶區(qū)組織灰度的變化，主要表現(xiàn)為靶區(qū)灰度從無到有、逐漸增強(qiáng)、然后減弱、并再增強(qiáng)的動(dòng)態(tài)變化過程。在不同灌注流量下，靶區(qū)聲像圖開始出現(xiàn)灰度變化的時(shí)間不同，灌注流量增加可以延遲輻照過程中聲像圖靶區(qū)灰度變化的出現(xiàn)。 3. PHIFU靶組織壞死體積與灌注流量關(guān)系：門靜脈灌注流量為442mL/min、588mL/min、746mL/min、886mL/min時(shí)，實(shí)驗(yàn)組靶區(qū)凝固性壞死體積分別是157.41±5.79mm3、118.70±5.96mm3、72.97±6.04mm3和44.45±3.49mm3；對(duì)照組靶區(qū)凝固性壞死體積分別是156.41±6.23mm3、120.57±6.44mm3、74.39±7.62mm3和45.96±5.72mm3，表明隨著肝血流量的增加，靶區(qū)壞死體積逐漸減少，兩者之間呈負(fù)相關(guān)關(guān)系。相同流量下，實(shí)驗(yàn)組與對(duì)照組比較差異無統(tǒng)計(jì)學(xué)性意義（P0.05）。 4. PHIFU靶組織壞死體積與血管關(guān)系：兩組鄰近血管的靶區(qū)組織均出現(xiàn)凝固性壞死的特征性變化。與對(duì)照組比較，PHIFU組靶區(qū)凝固性壞死體積明顯增加。其中，實(shí)驗(yàn)組和對(duì)照組在靶區(qū)位于血管后方的壞死體積分別為79.72±4.94mm3和25.53±2.08mm3，靶區(qū)位于血管前方的壞死體積分別為85.6±10.23mm3和28.34±7.28mm3，兩組比較，差異均具有顯著的統(tǒng)計(jì)學(xué)性意義（P0.05）。 5. PHIFU對(duì)靶區(qū)鄰近血管的損傷作用：實(shí)驗(yàn)組和對(duì)照組分別對(duì)血管，血管前、后方靶區(qū)肝組織輻照后，肉眼觀察兩組靶區(qū)，均未發(fā)現(xiàn)明顯的血管損傷表現(xiàn)，血管經(jīng)HE染色和維多利亞藍(lán)和麗春紅血管纖維染色，光鏡下觀察見血管壁結(jié)構(gòu)完整，內(nèi)皮細(xì)胞和血管壁纖維組織未出現(xiàn)損傷。 結(jié)論： 1. PHIFU消融肝臟的組織學(xué)變化表現(xiàn)為典型的凝固性壞死，損傷區(qū)和非損傷區(qū)邊緣清晰。 2. PHIFU輻照過程中，B超能實(shí)時(shí)觀察靶區(qū)聲像圖灰度的變化,呈現(xiàn)灰度增強(qiáng)、減弱，再增強(qiáng)的動(dòng)態(tài)變化過程。 3.血流速度能影響PHIFU消融肝組織的效果，隨著肝血流速度的增加，靶區(qū)壞死體積逐漸減少；同時(shí)，血流速度增加可以延遲輻照過程中聲像圖靶區(qū)灰度變化的出現(xiàn)。 4. PHIFU能用比連續(xù)波HIFU更少的能量達(dá)到相似的損傷體積。 5.與連續(xù)波HIFU輻照比較，PHIFU能明顯增加靠近血管靶區(qū)的凝固性壞死體積。 6. PHIFU對(duì)血管或者靶區(qū)鄰近血管均無明顯的直接損傷作用。
[Abstract]:Research background
At present, the clinical application of high intensity focused ultrasound (high intensity focused ultrasound, HIFU) therapy is a high power continuous wave irradiation on the focus, using its thermal effect to ablation the target tissue. Pulse high intensity aggregation ultrasound (pulsed highintensity focused ultrasound, PHIFU) is continuous with the existing HIFU emission. The treatment of wave ablation is different, and its treatment is pulse type, which is composed of pulse irradiation time and intermittent time. Earlier experimental study found that PHIFU could produce obvious cavitation effect and cause tissue damage in target area.
As a kind of intermittent irradiation, PHIFU may reduce the normal tissue damage caused by the energy deposition on the target acoustic channel by continuous wave irradiation. As a potential new therapeutic model, the histological changes of PHIFU ablation and the ultrasound imaging features of the target area, the effect of blood flow velocity on the effect of PHIFU ablation is clinical application. An important research content before the treatment model. This subject uses the clinical HIFU tumor treatment equipment to observe the changes of the volume of coagulation necrosis and the characteristics of the B-ultrasound image by regulating the perfusion flow of the liver in the isolated pig liver perfusion model, as well as the effect of the liver blood vessels on the effect of PHIFU ablation, and to explore the velocity of blood flow and blood. The effect of catheter on PHIFU ablation of liver tissue and the changes of target ultrasound imaging provide a new therapeutic mode and parameters for the clinical application of HIFU.
objective
1. to investigate the effect of blood flow velocity on PHIFU ablation of liver tissue and the changes of target ultrasound.
2. to investigate the effect of blood vessel on PHIFU ablation of liver tissue and vascular injury.
Method
1. the characteristics and ultrasonographic changes of PHIFU ablation liver tissue under different hepatic perfusion flow rate
Experimental animals: pig liver was provided by a slaughterhouse. The liver was removed from 2 to 3min after the death of the pig. The liver perfusion model of the porcine liver was established through the portal vein, the hepatic artery and the inferior vena cava.
Experimental method
(1) the control group was irradiated by continuous wave HIFU, and PHIFU irradiated as the experimental group. The radiation parameters were set: pulse repetition frequency 100Hz, irradiation power 80W, depth 20mm. experimental group 20%, irradiation time 25s, control group duty cycle 100%, and irradiation time 10s. by adjusting the speed of portal vein bypass pump in the extracorporeal circulation machine, so that the flow of portal vein was respectively 442mL/min, 588mL/min, 746mL/min, 886mL/min.
(2) under the different perfusion flow, the liver was perfused in vitro by PHIFU fixed-point irradiation. In the process of irradiation, the experimental group was used to observe the changes of the target image in real time by B-ultrasound, and to analyze the law of the change of the target area in the target area, and the experiment was repeated 20 times in each group.
(3) after PHIFU irradiation, the liver tissue was incised and perfused to find the largest injury surface of the target tissue, and the damage of the necrotic region was measured and recorded. The volume of coagulation necrosis was calculated, the local material was obtained, and the histological changes in the target area were observed.
The effect of 2. hepatic vessels on PHIFU ablation of liver tissue
Experimental methods:
(1) two radiation modes of HIFU pulse wave (experimental group) and continuous wave (control group) are used. The radiation parameters are sound power 80W, occupying ratio 20%, irradiation time 50s and sound power 80W, occupying ratio 100%, irradiation time 10s, irradiation depth 40mm, and pulse repetition rate of 100Hz.
(2) to find the suitable treatment level by HIFU airborne ultrasound, the blood vessels with a diameter of about 4mm were found. The blood vessels, the distance from the blood vessels, and the liver tissues at the rear 3mm were located as the target area respectively. The target liver was irradiated at fixed points, and the experiment was repeated 15 times in each group.
(3) after irradiation, the liver tissue was cut, the maximum damage surface of the target area was found, the necrotic area was measured and recorded, the volume of coagulation necrosis was calculated. The damage of the liver tissue and blood vessels in the two groups of target areas was observed by the naked eye, and the histological changes were observed.
Result:
1. PHIFU ablation of liver tissue: the same as continuous wave HIFU irradiation, the liver tissue in the target area of group PHIFU had the characteristic changes of coagulation necrosis, the edge of the damaged area and the non damaged area was clear, and no obvious cavity formation was found in the damaged area.
2. PHIFU ablation of liver tissue ultrasound imaging changes: when PHIFU irradiated in vitro perfusion liver, B-ultrasound can show the changes in the gray level of the target tissue in real time. The main manifestation is that the gray level of the target area is gradually increased, then the dynamic change process is strengthened and then strengthened. When the time is different, the increase of perfusion rate can delay the appearance of the gray level change of the target in the process of irradiation.
3. PHIFU target tissue necrosis volume and perfusion flow relationship: portal venous perfusion flow is 442mL/min, 588mL/min, 746mL/min, 886mL/min, the volume of coagulation necrosis in the target area of the experimental group is 157.41 + 5.79mm3118.70 + 5.96mm3,72.97 + 6.04mm3 and 44.45 + 3.49mm3 respectively, and the volume of coagulative necrosis in the target area of the control group is 156.41 + 6.23mm3120.57 respectively. 6.44mm3,74.39 + 7.62mm3 and 45.96 + 5.72mm3 showed that the necrosis volume of target area decreased gradually with the increase of hepatic blood flow, and there was a negative correlation between the two groups. There was no statistical difference between the experimental group and the control group (P0.05) under the same flow rate.
4. PHIFU target tissue necrosis volume and blood vessel relation: the target area of two groups of adjacent vessels all appeared the characteristic change of coagulation necrosis. Compared with the control group, the volume of coagulation necrosis in the target area of the PHIFU group was obviously increased. The bad dead volume of the experimental group and the control group in the target area behind the vessels was 79.72 + 4.94mm3 and 25.53 + 2.08mm, respectively. 3. The necrosis volume of the target area in front of the blood vessel was 85.6 (+ 10.23) mm3 and 28.34 (+ 7.28) mm3, respectively. The difference between the two groups was statistically significant (P 0.05).
The effect of 5. PHIFU on the injury of the adjacent vessels in the target area: the experimental group and the control group irradiated the blood vessels, anterior vessels and the rear target area respectively. No obvious vascular damage was found in the two groups of target areas. The blood vessels were stained with HE and Vitoria blue and Lichun red blood vessel fibers. The vascular wall structure was observed under the light microscope. No damage was found in the skin cells and the fibrous tissue of the vascular wall.
Conclusion:
1. the histological changes of the PHIFU ablation liver showed typical coagulative necrosis, and the edges of the injured area and the non injured area were clear.
2. In the process of PHIFU irradiation, B-mode ultrasound can observe the change of the gray level of the target sonogram in real time, showing the dynamic process of gray level enhancement, weakening, and reinforcing.
3. the velocity of blood flow can affect the effect of PHIFU ablation on the liver tissue. With the increase of the velocity of the liver blood flow, the necrosis volume of the target area decreases gradually. At the same time, the increase of the velocity of blood flow can delay the appearance of the gray change in the target area of the sound image during the irradiation.
4. PHIFU can achieve similar damage volume with less energy than continuous wave HIFU.
5. compared with continuous wave HIFU irradiation, PHIFU significantly increased the coagulation necrosis volume near the vascular target area.
6. PHIFU had no obvious direct damage to blood vessels or adjacent vessels in target area.
【學(xué)位授予單位】：重慶醫(yī)科大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：R730.55

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