The application of three-dimensional contrast-enhanced ultrasound to measure volume of affected tissue after HIFU treatment for localized prostate cancer

INTRODUCTION: Adequate monitoring of volume and location of affected tissue might provide helpful information when performing localized ablative therapy for prostate cancer. We hypothesize that the change in blood flow patterns after therapy in comparison to the blood flow pattern prior to therapy can be used to locate and quantify the amount of affected tissue due to the therapy. We describe the use of three-dimensional contrast-enhanced power Doppler ultrasound (3D-CE-PDU) to determine its additive value to visualize the extent of tissue defects created by high-intensity focused ultrasound (HIFU) in correlation with the histopathology of the prostatectomy specimen. MATERIALS AND METHODS: Nine patients with biopsy-proven localized prostate cancer, who gave informed consent, were included in the protocol. HIFU treatment was performed 1 week in advance of radical retropubic prostatectomy (RRP) as part of a protocol to study the value of HIFU treatment as local ablative therapy for clinical T(1-2)N(0)M(0) prostate carcinoma. 3D-CE-PDU was performed 1 day prior to unilateral HIFU treatment of the affected lobe on biopsy indication and 1 day before RRP using 2.5 g Levovist((R)) (Schering AG, Germany) microbubble ultrasound contrast agent and a Kretz((R)) Voluson 530D ultrasound scanner (Kretztechnik AG, Austria). Ultrasound data and pathology whole-mount sections were stored digitally to allow off-line processing. Human interpretations of HIFU measurements in three-dimensional ultrasound data were based on gray-scale information (local increase in gray level) in combination with power Doppler mode (absence of blood flow). Histopathological analysis of the whole-mount section revealed a broad band of hemorrhagic necrosis in the HIFU-treated area. Using both the ultrasound data and the pathology sections, the total volume of the prostate and of the HIFU-treated area was measured, and relative volumes were obtained. RESULTS: Visual inspection of the three-dimensional reconstruction of contrast-enhanced Doppler measurements revealed the HIFU-affected prostate tissue by the absence of a blood flow pattern. Paired t tests of the relative HIFU volume indicated that Doppler results (mean 21.7%, SD +/-10.8%) differed from the pathology results (mean 32.6%, SD +/-16.0%), but a good correlation was found between the relative pathology HIFU volume (Pearson correlation r = 0.94, p<0.0015) and mean 3D-CE-PDU HIFU. Closer inspection of the pathology specimen revealed that the outer ring of the macroscopic hemorrhagic necrosis overestimated the actually dead tissue. On microscopy, the border of dead tissue appeared to be 1-2 mm inside the macroscopically identified red hemorrhagic band. 3D-CE-PDU HIFU volumes indicated by the single observers were not statistically different and correlated very well (Pearson correlation r = 0.98, p<0.001). CONCLUSION: The results illustrate that 3D-CE-PDU is a promising method to determine the size of the defect of HIFU ablative therapy for prostate carcinoma. The absence of blood flow indicated by three-dimensional power Doppler ultrasound images reflects affected tissue after HIFU treatment, and volume measurements of these areas can quantify the amount of affected tissue.     

Transrectal high-intensity focused ultrasound for treatment for patients with biochemical failure after radical prostatectomy

Four patients with biochemical prostate-specific antigen (PSA) failure with suspected local recurrence at the vesico-urethral anastomotic site after radical prostatectomy were treated using a high-intensity focused ultrasound (HIFU) device (Sonablate 500) under caudal or spinal anesthesia. The pretreatment PSA levels ranged from 0.318 to 0.898 ng/mL and their Gleason scores ranged between 5 and 7. HIFU treatment was carried out six times in four patients. The median time of operation and follow-up period were 30 min (range, 15-37) and 13 months (range, 7-18), respectively. In all patients, the median PSA levels decreased from 0.555 ng/mL (range, 0.318-0.898) to 0.137 ng/mL (range, 0.102-0.290). The median PSA nadir after each HIFU was 0.054 ng/mL (range, 0.008-0.097). No major complications were noted. HIFU may be useful for the therapy of vesicourethral anastomostic lesion in patients with PSA failure after prostatectomy.     

Real-time Magnetic Resonance–guided High-intensity Focused Ultrasound Focal Therapy for Localised Prostate Cancer: Preliminary Experience

Five patients with unifocal, biopsy-proven prostate cancer (PCa) evident on multiparametric magnetic resonance imaging (MRI) were treated with magnetic resonance–guided focused ultrasound (MRgFUS) ablation before radical prostatectomy (RP). An endorectal probe featuring a phased-array focused ultrasound transducer was positioned for lesion ablation under MRI guidance. The tissue temperature and accumulation of thermal damage in the target zone was monitored during the procedure by MRI thermometry. Overlap between the ablation area and the devascularisation of the target lesion was evaluated by contrast-enhanced MRI performed immediately after treatment. The procedure was uneventful, and no adverse events were observed. RP was safely performed without significant surgical difficulties in relation to the previous MRgFUS treatment. The histopathology report showed extensive coagulative necrosis, with no residual tumour in the ablated area. Significant bilateral residual tumour, not evident on pretreatment MRI, was observed outside the treated area in two patients. MRgFUS ablation of focal localised PCa is feasible and, if confirmed in appropriate studies, could represent a valid option for the focal treatment of localised PCa.     

Can color doppler predict the uniformity of HIFU‐induced prostate tissue destruction?

BACKGROUND: Tissue blood perfusion influences the results of some hyperthermia and thermotherapy procedures, but its role in the outcome of prostate cancer treatment by high-intensity focused ultrasound (HIFU) has not been evaluated yet. We evaluated preoperative prostate color Doppler as a predictor of the efficacy of HIFU treatment. METHODS: Thirty-five patients underwent pre- and post-contrast color Doppler examination of the prostate before HIFU treatment. Specific software was used to calculate, on color Doppler images, the color pixel density (CPD), and the specific flow (SF, i.e., mean velocity x CPD) in different regions of interest. Post-treatment sextant biopsies were obtained in 31 patients, 5.8 +/- 2.8 months after HIFU treatment. RESULTS: No significant correlation was found between the uniformity of HIFU-induced tissue destruction observed on control biopsies and the pre-treatment CPD/SF values in any region of interest, either before or after contrast injection. On the other hand, history of radiation therapy was significantly associated with homogeneous tissue destruction and history of hormone therapy was significantly associated with incomplete tissue destruction. CONCLUSIONS: Color Doppler cannot predict the uniformity of HIFU-induced tissue destruction. History of radiation therapy was found to be a factor of favorable prognosis and history of hormone therapy was found to be a factor of poor prognosis in our population.     

高强度聚焦超声对恶性实体肿瘤血管的破坏作用

目的：探讨高强度聚焦超声（HIFU）体外破坏恶性实体肿瘤血管的临床影像学变化和病理学变化。方法：HIFU治疗恶性实体肿瘤患者164例，通过数字减影血管造影、彩超、放射性核素显影分析肿瘤血管治疗前后的功能状态；30例患者治疗后常规外科手术，观察肿瘤血管的病理学变化。结果：临床影像学检查显示与治疗前比较，治疗后肿瘤异常血管网被破坏，肿瘤内血供减少或消失；光镜下肿瘤毛细血管、小血管管壁结构出现不可逆性损伤表现，腔内有血栓形成。结论：HIFU能从体外破坏肿瘤血管，加强了HIFU杀死肿瘤细胞的直接效应，这种选择性破坏血管作用有重要的临床意义。     

MRI appearance of prostate following transrectal HIFU ablation of localized cancer.

OBJECTIVES: To evaluate the accuracy of gadolinium-enhanced MRI in gauging the extent of the tissue damage induced by transrectal high intensity focused ultrasound (HIFU) therapy and to assess how well the results obtained with this modality correlate with histological findings (control biopsies). METHODS: Twenty-one patients with biopsy-proven prostate cancer (T1-T2-T3a, Nx, M0) who gave informed consent were included in the protocol. They underwent pre- and postoperative (2-5 days after HIFU treatment) MR examinations. Fifteen patients also underwent a follow-up MR examination 1-5 months postoperatively. MR findings were compared with the results of postoperative transrectal biopsy examinations. RESULTS: The prostate volume increased after the HIFU session from 43.9+/-18.6 to 52.1+/-21 cm(3) by day 2 (p<0.001). On fat-saturated gadolinium-enhanced T1-weighted images, the treated area appeared as a hypointense zone surrounded by a peripheral rim of enhancement in all patients. A positive correlation (r = 0.75) was found between the volume of the hypointense zone measured at days 2-5 (30+/-11 cm(3), 67% of the posttreatment prostate volume) and the theoretical target volume (22+/-5 cm(3), 61% of the initial prostate volume). MRI showed that the anterior part of the base was not reached by the ultrasound beam. The mean volume of the untreated zone (prostate without any MRI modifications) was 8 cm(3) (range, 0.4-36). No correlation was found between the MRI appearance of the treated area and the intensity of the necrosis or the presence of foci of residual, viable cancer. CONCLUSION: Gadolinium-enhanced MRI is an accurate way of determining the extent of tissue damage induced in HIFU ablative therapy, but cannot predict histological results.     

Das Lokalrezidiv des Prostatakarzinoms nach kurativer Therapie

In terms of effectivity and impact, no ideal approach is as yet available for treatment of local recurrence of prostate cancer. We direct our attention mainly toward high-intensity focused ultrasound (HIFU). HIFU therapy (Ablatherm) is only performed in our department when the following criteria are met: the recurrent tumor must be visualizable with imaging procedures (for HIFU, transrectal ultrasound is employed), the tumor must be accessible to the scanner head (penetration depth: 25 mm), and finally the diagnosis of recurrent tumor has to be histologically confirmed. An indisputable advantage of HIFU is the option of easily administering HIFU therapy for a second time in the presence of tumor remnants or in the event of cancer recurrence. Depending on the primary cancer treatment given, salvage HIFU achieves a biopsy-proven tumor-free state in 60-74% of patients. These results are in line with those that can be obtained with other salvage strategies (radical prostatectomy, radiation therapy). However HIFU shows reduced postoperative morbidity with less side effects.     

Extracorporeally induced ablation of renal tissue by high-intensity focused ultrasound

OBJECTIVE: To investigate the safety and the effects on healthy renal tissue of high-intensity focused ultrasound (HIFU) applied extracorporeally. PATIENTS, MATERIALS AND METHODS: Ultrasound waves (1.04 MHz) created by a cylindrical piezo-ceramic element were focused by a parabolic reflector to a physical focus size of 32 x 4 mm (-6 dB). For an in vivo study, HIFU was applied to the healthy tissue of 24 kidneys, monitored by ultrasonography, with a maximum power of 400 W and a spatially averaged intensity (ISAL) in the focus of 1192 W/cm(2). Fourteen kidneys were removed immediately after ablation to evaluate the side-effects and the effects in the focal zone, and 10 kidneys were removed delayed after 1, 7 and 10 days. The clinical study consisted of 19 patients requiring radical nephrectomy for a renal tumour. HIFU was applied to the healthy tissue of 19 kidneys (up to 1600 W, I(SAL) = 4768 W/cm(2)) before proceeding with the radical nephrectomy. RESULTS: There were no major complications after applying HIFU to the 43 kidneys. Side-effects included skin burns (grade 3) in two patients. During the follow-up there were no further HIFU-specific side-effects. In one case (in vivo study) there was a thermal lesion of the small intestine, which was due to mis-focusing. HIFU effects in the focal zone immediately after application were: interstitial haemorrhages, fibre rupture, shrinking of the collagen fibres, and coagulation necrosis. These effects occurred sporadically, and their number and size did not correspond to the number of HIFU pulses applied. After 7 and 10 days, there was a well-demarcated coagulation necrosis in vivo. CONCLUSION: Using this device, extracorporeally applied HIFU can ablate healthy kidney tissue in vivo in combination with diagnostic online ultrasonography. The technique is safe and resulted only in minor complications (skin burns). Refinements in the technology are essential to establish HIFU as a noninvasive treatment option that allows complete and reliable tissue ablation.     

Technical characterization of an ultrasound source for noninvasive thermoablation by high-intensity focused ultrasound

OBJECTIVE: To develop a generator for high-intensity focused ultrasound (HIFU, a method of delivering ultrasonic energy with resultant heat and tissue destruction to a tight focus at a selected depth within the body), designed for extracorporeal coupling to allow various parenchymal organs to be treated. MATERIAL AND METHODS: The ultrasound generated by a cylindrical piezo-ceramic element is focused at a depth of 10 cm using a parabolic reflector with a diameter of 10 cm. A diagnostic B-mode ultrasonographic transducer is integrated into the source to allow the focus to be located in the target area. The field distribution of the sound pressure was measured in degassed water using a needle hydrophone. An ultrasound-force balance was used to determine the acoustic power. These measurements allowed the spatially averaged sound intensity to be calculated. The morphology and extent of tissue necrosis induced by HIFU was examined on an ex-vivo kidney model. RESULTS: The two-dimensional field distribution resulted in an approximately ellipsoidal focus of 32 x 4 mm (- 6 dB). The spatially maximum averaged sound intensity was 8591 W/cm2 at an electrical power of 400 W. The lesion caused to the ex-vivo kidney at this maximum generator power with a pulse duration of 2 s was a clearly delineated ellipsoidal coagulation necrosis up to 8.8 x 2.3 mm (length x width) and with central liquefied necrosis of 7.9 x 1.9 mm. CONCLUSION: This newly developed ultrasound generator with a focal length of 10 cm can induce clear necrosis in parenchymal tissue. Because of its specific configuration and the available power range of the ultrasound generator, there is potential for therapeutic noninvasive ablation of tissue deep within a patient's body.     

A novel approach to energy ablative therapy of small renal tumours: laparoscopic high-intensity focused ultrasound

OBJECTIVE: High-intensity focused ultrasound (HIFU) permits targeted homogeneous ablation of tissue. The objective of this phase 1 study was to evaluate the feasibility of HIFU ablation of small renal tumours under laparoscopic control. PATIENTS AND METHODS: Ten kidneys with solitary renal tumours were treated with a newly developed 4.0 MHz laparoscopic HIFU probe. In the first two patients with 9-cm tumours, a defined marker lesion was placed prior to laparoscopic radical nephrectomy. In eight patients with a mean tumour size of 22 mm (range, 11-40), the tumour was completely ablated as in curative intent, followed by laparoscopic partial nephrectomy in seven tumours. One patient had post-HIFU biopsies and was followed radiologically. Specimens were studied by detailed and whole-mount histology, including NADH stains. RESULTS: Mean HIFU insonication time was 19 min (range, 8-42), with a mean targeted volume of 10.2 cm3 (range, 9-23). At histological evaluation both marker lesions showed irreversible and homogeneous thermal damage within the targeted site. Of the seven tumours treated and removed after HIFU, four showed complete ablation of the entire tumour. Two had a 1- to 3-mm rim of viable tissue immediately adjacent to where the HIFU probe was approximated, and one tumour showed a central area with about 20% vital tissue. There were no intra- or postoperative complications related to HIFU. CONCLUSION: The morbidity of laparoscopic partial nephrectomy mainly comes from the need to incise highly vascularized parenchyma. Targeted laparoscopic HIFU ablation may render this unnecessary, but further studies to refine the technique are needed.     

高强度聚焦超声治疗55例原发性肝癌后的早期影像学变化

目的：研究高强度聚焦超声（HIFU）治疗原发性肝癌（PLC）的早期影像学变化，为建立HIFU治疗肝癌的评价标准提供依据。方法：HIFU治疗本组55例PLC病人，观察治疗前后彩色多普勒超声、DSA、CT或MRI的变化。结果：与治疗前比较，经HIFU治疗后1-2周内肝癌出现治疗有效的影像学变化。其中，MRI是评价疗效的最佳检查方法，主要表现为T1和T2加权相信号的变化，以及动态增强相癌灶血液供应消失，边缘出现环状薄层的强化带。结论：MRI能及时判断HIFU是否完全灭活肝癌，治疗区有无残存癌组织和确定治疗范围。     

High intensity focused ultrasonic destruction of hepatic parenchyma

OBJECTIVE: High intensity focused ultrasound (HIFU) is an effective and precise method of focal tumoral destruction since it is associated with imagery. This method is widespread for the endorectal treatment of prostatic adenocarcinomas. HIFU seem appropriate for the treatment of liver tumors but its use needs to be experimentally tested in vivo. The aim of the work is to study the feasibility, tolerance and effectiveness of the destruction of porcine liver by HIFU. MATERIAL AND METHODS: Ten pigs had liver destruction by HIFU after coeliotomy. Four to 5 2,3 cm(3) HIFU lesions were performed per animal under ultrasonographic control. The study included biological surveillance and an autopsy was performed 4 to 24 hours later for histological examination of the liver. RESULTS: The destruction of the liver was feasible in all cases and the 4 lobes of the liver could be treated. The general and biological tolerance of the procedure was excellent. Ultrasonographic features of the HIFU lesions were defined. The histological examination of the lesions showed well-circumscribed necrosis areas associated with cavitation or histological deficiencies of various degrees. CONCLUSION: This work demonstrated that liver destruction by HIFU is a feasible and effective method with low morbidity. A long-term experimental study is necessary before comtemplating its clinical use.     

Extracorporeal application of high-intensity focused ultrasound for prostatic tissue ablation

OBJECTIVE: To investigate the efficacy and safety of extracorporeal prostatic tissue ablation using high-intensity focused ultrasound (HIFU) in vivo in animals, and in a clinical feasibility study in men, as this is an investigational minimally invasive treatment alternative for locally confined prostatic carcinoma, but may have significant side-effects. PATIENTS, MATERIALS AND METHODS: Ultrasound (1.04 MHz excitation frequency) was generated by an extracorporeal cylindrical piezo-ceramic element and focused by a paraboloidal reflector to a focal size of 32 x 4 mm. The focal distance and aperture diameter were both 100 mm. HIFU was applied extracorporeally at different intensities and pulse duration (up to 6 s) to 11 dog prostates in vivo (median intensity 1192 W/cm2) and eight patients (median intensity 3278 W/cm2, range 2384-3576) under general anaesthesia. The lesions were assessed macroscopically and histologically after HIFU and any side-effects evaluated. RESULTS: Thermoablation was feasible in vivo and in all patients. Macroscopic analysis and histology showed sharply demarcated coagulative necrosis. Side-effects, including skin and rectal burns, occurred only after transvesical application in the in vivo study. There were no side-effects in patients after perineal application. CONCLUSION: Extracorporeal HIFU is technically feasible and induces sharply demarcated tissue damage in the prostate. From the early results of this phase 1 study, the perineal approach seems to be safe.     

High-intensive focused ultrasound in localized prostate cancer

BACKGROUND AND PURPOSE: The results of the standard treatment for prostate cancer-radical prostatectomy-are not entirely satisfactory. A new local therapy, transrectal high-intensive focused ultrasound (HIFU), has been developed. We reviewed our experience with HIFU for palliation of localized prostate cancer. PATIENTS AND METHODS: Our series included 65 men with confirmed prostate cancer without detectable metastases who were not suitable candidates for radical prostatectomy. After prophylactic suprapubic cystostomy, the patients were treated using the Ablatherm version 2.32 under spinal anesthesia. The effects were monitored by serum prostate specific antigen assays, digital rectal examination, and biopsy. The mean follow-up is 10 months (range 1-18 months). RESULTS: There were no intraoperative or postoperative deaths, and there have been no deaths from prostate cancer. Residual cancer was detected in 35% of the patients in whom only biopsy-positive portions of the prostate were treated and 17% of those in whom the entire gland was treated. Retreatment was performed 1 month after the first session in these patients. The prostate volume increased an average of 30% after treatment, but by 3 months, the gland was 10% to 20% smaller than its original size. Three patients suffered complications secondary to overheating of the rectal wall or treatment too close to the external urethral sphincter. CONCLUSION: The low morbidity, minimal invasiveness, avoidance of systemic side effects, and potentially curative effect make HIFU a potentially useful option for the treatment of localized prostate cancer.     

高强度聚焦超声肿瘤治疗技术原理

高强度聚焦超声波(high-intensity focused ultrasound,HIFU)是利用超声波良好的方向性、可穿透性、生物组织吸声特性等,将体外超声换能器发射的低声强超声波准确聚焦于体内的肿瘤靶组织处.聚焦后局部组织所吸声能转化为热能可使组织瞬间升温至蛋白变性阈值温度(60℃以上).该技术可使肿瘤细胞发生不可逆凝固性坏死,但不伤及焦点周围正常组织.

Abstract：

High intensity focused ultrasound (HIFU) is a novel physical tumor therapeutic technology which applies the ultrasound well targeting, focusing, tissue absorbing property, and so on. It focused outer transducer low intensity ultrasound wave and targeted in the tumor, whichcan raise the temperature above 60℃ rapidly and induce tissue irreversible coagulation necrosis, with no damage to the surrounding normal tissue. It is a new physical tumor treatment technology.     

High-intensity focused ultrasound and localized prostate cancer: efficacy results from the European multicentric study

PURPOSE: To describe the safety and efficacy of high-intensity focused ultrasound (HIFU) for the treatment of prostate cancer as assessed in a Phase II/III prospective multicentric clinical trial. PATIENTS AND METHODS: Patients (N = 402) presenting with localized (stage T(1-2)N(0-x)M(0)) prostate cancer between 1995 and 1999 at six European sites who were not candidates for radical prostatectomy were treated with HIFU under general or spinal anesthesia. Their mean age was 69.3 +/- 7.1 (SD) years, the mean prostate volume 28.0 +/- 13.8 cc, and the mean serum prostate specific antigen (PSA) concentration 10.9 +/- 8.7 ng/mL. Nearly all (92.2%) of the patients had one to four positive biopsy samples at baseline. The Gleason scores were 2 to 4 for 13.2% of the patients, 5 to 7 for 77.5%, and 8 to 10 for 9.3%. During the follow-up, random sextant biopsies and serum PSA measurements were performed. Any positive sample in biopsies performed after the last treatment session resulted in a "HIFU failure" classification. RESULTS: The patients received a mean of 1.4 HIFU sessions. The mean follow-up duration was 407 days (quartile 1 135 days, median 321 days, quartile 3 598 days). The negative biopsy rate observed in the T1-2 primary-care population was 87.2%. These results were also stratified according to the usual disease-related risk classification, and as much as a 92.1% negative biopsy rate was observed in low-risk patients. Nadir PSA results correlated with prostate size and the clinical procedure. CONCLUSION: These short-term results obtained on a large cohort confirm that HIFU is an option to be considered for the primary treatment of localized prostate cancer.     

Indications, techniques and outcomes of high-intensity focused ultrasound (HIFU) for the treatment of localized prostate cancer

High-intensity focused ultrasound (HIFU) is a minimally invasive alternative for patients with localized prostate cancer, not suitable for radical prostatectomy because of a life expectancy less than 10 years or because of major co-morbidities precluding surgery. HIFU can be performed in patients with LUTS (associated TURP) or with a previous history of BPH surgery. HIFU is repeatable after the initial procedure if a recurrent cancer is diagnosed on control biopsies. Furthermore, this therapy is a viable option for patients with a local relapse after external beam radiation therapy: oncologic efficacy is conversely related to the initial prostate cancer stage before radiation therapy.     

聚焦超声消融治疗胰腺癌的临床观察

目的探讨高强度聚焦超声(high intensity focused ultrasound,HIFU)消融治疗胰腺癌的疗效和安全性.方法采用JC型高强度聚焦超声治疗系统,消融治疗44例胰腺癌患者.观察治疗前后的影像学变化及临床症状,评价HIFU治疗的疼痛缓解程度、生存期及不良反应.结果44例患者经HIFU治疗后,疼痛缓解率为94.74%,1、3、5年生存率分别为15.91%、6.82%、2.27%,中位生存时间为8个月(3～71个月).无上消化道出血或胃肠穿孔等严重并发症.增强CT或MRI显示HIFU治疗区内组织消融.结论HIFU是一种治疗胰腺癌的有效方法.该法无创、安全性较高、止痛效果明显,适合病情较重、不能耐受其他方法治疗的患者.     

Principles and results of high-intensity focused ultrasound for localized prostate cancer

Focused ultrasound holds promise in a large number of therapeutic applications. It has long been known that high-intensity focused ultrasound (HIFU) can kill tissue through coagulative necrosis. However, it is only in recent years that practical clinical applications are becoming possible, with the development of high-power ultrasound arrays and noninvasive monitoring methods. In the last decade, HIFU have been adapted and used to treat localized prostate cancer and it is now commercially available in Europe. In this article, preclinical studies and clinical development of prostate HIFU as well as early clinical results from our center and international studies are reviewed. Early results demonstrated that prostate HIFU is efficient to obtain local control for low- and intermediate-risk localized prostate cancer; however, long-term follow-up is still needed to estimate the efficacy of prostate HIFU in terms of specific cancer mortality. This makes HIFU a viable alternative in patients not candidate for radical therapy.     

高强度聚焦超声治疗兔肾VX2肿瘤的实验研究

目的探讨高强度聚焦超声（ＨＩＦＵ）治疗肾肿瘤的效果。方法采用兔肾ＶＸ２肿瘤模型进行ＨＩＦＵ辐照。辐照后不同时期处死动物以观察其病理变化。另以辐照组及对照组动物各６只,于２周后处死,比较肿瘤生长及肺转移的情况。结果ＨＩＦＵ辐照后肿瘤细胞立即发生凝固性坏死,电镜下亦见到不可逆的破坏。２周后有４只动物的肿瘤原发灶已被完全破坏;另２只靶区外有少量肿瘤残存,其体积为６２．８ｍｍ３和９．４ｍｍ３,而对照组的肿瘤平均体积为（１７５１．１±３５３．７）ｍｍ３。辐照组有２只（３３％）发生肺转移,转移结节数为９和３;对照组全部发生肺转移,转移结节数为５２±３４。两组差异有显著性。结论ＨＩＦＵ对兔肾ＶＸ２肿瘤有很强的杀伤作用。