Laser-induced interstitial thermotherapy of liver tumors using real-time MR-monitoring sequence: fundamental and clinical examinations

作为基础实验，在不同的激光照射参数下，对体内和体外的动物肝脏进行了激光照射。使用的设备是Dornier Medilas Fibertom 5100(德国Dornier Medizintech ik)，它产生波长为1064 nm的Nd：YAG激光。从宏观和微观两个方面对热消融损伤的大小进行评估。我们研究了激光输出(W)与病变大小的关系，照射时间与病变大小的关系，以及体内和体外肝脏病变大小的差异。结果表明，当激光输出25W(最大输出)时，热消融病变的大小最大，并与激光照射时间成比例增加。此外，在相同的参数下，体内肝脏的病变面积比体外肝脏小约1/9。因此，在实际的临床应用中，为了有效地治疗肝脏肿瘤，激光…使用德国西门子公司的0.2T Magnetom Open Viva的开放磁场，对2D-Flash和True FISP等几种MR序列用于动物肝脏LITT的在线监测进行了评估。激光经激光针尖照射，输出功率分别为25W和10W。在检查过程中，大约每30秒获得一次序列MR图像。比较所有MR图像的信号变化和动物肝脏的实际温度变化，2D-FLASH在实时监测LITT方面优于True FISP法。对于LITT的临床应用，使用专用敷贴器将激光纤维置入肝脏肿瘤。未经厚生劳动省批准临床使用。因此，以患者为例的转移性肝肿瘤的强制治疗还没有完成，还将是未来的课题。然而，我们的动物实验正在检查LITT程序的安全性。LITT有望成为转移性肝肿瘤的有效治疗选择，尤其是考虑到莱斯先生对热消融变化的实时监测。

As a fundamental experiment, laser irradiation was applied to both in-vivo and in-vitro animal livers, using various parameters under various parameters of laser application. The equipment used is Dornier Medilas Fibertom 5100 (Dornier Medizintechnik, Germany) which generates Nd:YAG laser with a wavelength of 1064nm. Size of thermoablative lesions were evaluated both macroscopically and microscopically. We evaluated a relationship between laser output (W) and lesion size, a relationship between irradiation time and lesion size, and a difference of lesion size between in-vitro and in-vivo liver.Consequently, it became clear that size of thermoablative lesion was the maximum at the output of 25W (maximum output) and increased in proportion to laser irradiation time. Moreover, lesion size of in-vivo liver turned out to be smaller than that of in-vitro liver by about 1/9 under same parameters. Therefore, in actual clinical application, in order to treat liver tumors effectively, a laser ou … More tput should be set as high as possible.Using 0.2T MAGNETOM OPEN VIVA (Siemens, Germany) of the open magnetic field, several MR sequences, including 2D-FLASH and True FISP, were evaluated for online monitoring of LITT of animal liver. Laser irradiation were applied through laser tip in 25W and 10W output. Serial MR images were obtained approximately every 30 second during procedure. Comparing signal changes of all MR images and actual thermal changes of animal liver, 2D-FLASH was superior to True FISP for real-time monitoring of LITT.For clinical application of LITT, laser fiber was placed into liver tumors using special applicator. Applicator is not approved for clinical use by Ministry of Health, Labor and Welfare. Therefore, enforcement to the patient to the actual example of metastatic liver tumors was not completed and will be a future subject. However, the safety of LITT procedure was being checked through our animal experiment. LITT is expected to be a useful therapeutic option for metastatic liver tumors, especially in view of the real-time monitor of the thermoablative change by MR. Less