Development of RF interstitial capacitive hyperthermic system for malignant brain tumor.

为了建立射频组织间电容加热的热疗系统，我们对射频天线的研制、植入手术技术和临床应用进行了研究。一项临床试验已经启动，以确定使用13.56MHz射频（RF）天线治疗恶性脑肿瘤的间质热疗的可行性。研制了直径为1.0mm的针式施加器（射频天线）。使用CT引导的立体定向装置将单个或多个（2-4个）天线插入脑肿瘤中。利用铜-康铜热电偶传感器监测脑和肿瘤的温度。对30例恶性脑肿瘤、22例恶性胶质瘤（原发性10例，复发性12例）、7例转移瘤和1例恶性淋巴瘤进行射频间质热疗。通过对比增强CT确定的肿瘤边缘在43.0 ℃下加热60分钟。每周1 ~ 2次，重复加热3-9次，平均5次，同时配合常规放疗或化疗。复发的胶质瘤仅用热处理。患者无局部疼痛或热感，对重复加热耐受良好。术后并发症除2例有少量积液、1例皮下感染、1例瘤内出血、2例有一过性神经症状外，无其他严重并发症。经CT评价疗效，CR 8例，PR 10例，ST 9例，PD 3例。大部分CR病例病灶周围低密度灶消失。这些初步结果表明，射频间质热疗似乎是治疗恶性脑肿瘤的有效方法，该技术创伤小，老年或低危患者的肿瘤以及深部肿瘤可以很好地应用。

In order to establish the hyperthermic system of RF interstitial capacitive heating, we studied development of RF antennas, operative technique for implant and clinical appling. A Pase I/II clinical trial has been initiated to determined the feasibility of an interstitial hyperthermia using 13.56MHz radiofrequency (RF) antennas in the treatment of malignant brain tumors. The needle type applicator (RF antennas) with diameter of 1.0mm was developed. A single or multiple (2-4) antennas were inserted into the brain tumor using a CT-guided stereotactic apparatus. The temperature of the brain and the tumor were monitored by the copper-constantan thermocouple sensors. The RF interstitial hyperthermia was performed on 30 patients with malignant brain tumors, 22 malignant gliomas (10 primary and 12 recurrent), 7 metastatic tumor and 1 malignant lymphoma. The rim of the tumors which were defined by contrast enhanced CT was heated at 43.0ﾟC for 60 minutes. The heating was repeated 3-9 (mean 5) times, once or twice a week, combined with conventional radiation or chemotherapy. The recurrent gliomas were treated with heat alone. The patients complained no local pain or heat sensation and well tolerated the repeated heating. No major complication occurred except liquorrhea in 2 cases, subcutaneous infection in one case, intratumoral hemorrhage in one case and trasient neurological symptoms in 2 cases. The anti-tumor effects were evaluated by CT and the treated tumors showd CR in 8, PR in 10, ST in 9 and PD in 3 cases, respectivery. In most of CR cases, the perifocal low density lesion also disappeared. These preliminary results indicated that the RF interstitial hyperthermia seemed to be effective in treatment of malignant brain tumors, this technique is less invasive and the tumors in aged or poor risk patients as well as deep-seated tumors can be good candidates for the application.