Megavoltage Ct-assisted Stereotactic Radiosurgery for Thoracic Tumors

本研究的目的是从症状缓解和局部控制的角度评价立体定向放射外科（SRS）与兆伏计算机断层扫描（MVCT）治疗胸部肿瘤的疗效。MVCT辅助定位验证和多叶准直器（MVC）的实时监测用于提高胸部SRS的准确性。15例患者的22个胸部肿瘤接受了本治疗。除一个肿瘤外，所有肿瘤均为各种原发性恶性肿瘤的转移。11例患者出现症状。治疗部位为胸壁/胸膜10例，肺野12例。对于肺肿瘤，临床靶区的中位体积为4.5 cc，中位外周剂量为20戈伊。对于胸壁/胸膜肿瘤，临床靶区的中位体积为40 cc，中位外周剂量为20戈伊。常规分割适形放射治疗（CRT）后，SRS在10个肿瘤。在21例符合评价条件的肿瘤中，有13例CR，6例PR和2例NC。局部控制持续时间范围为0.6至82个月，中位时间为8个月。大多数有症状的患者立即得到缓解。肺间质变化有限。对两名患者进行的尸检显示了显着的组织学效果，对肺的损伤最小。MVCT辅助SRS的几何准确性似乎可以提高胸部恶性肿瘤治疗的临床疗效和安全性。

The aim of the study was to evaluate the efficacy of stereotactic radiosurgery (SRS) for thoracic tumors with megavoltage computed tomography (MVCT) from the point of view of symptom palliation as well as local control. MVCT-assisted positioning verification and real-time monitoring for a multi-leaf collimator (MVC) were used to enhance the accuracy of the thoracic SRS. Twenty-two thoracic tumors in 15 patients underwent the present treatment. All but one tumor were metastases from various primary malignancies. Eleven patients were symptomatic. The treatment site was the chest wall/pleura in 10 tumors, the lung field in 12 tumors. The median volume of the clinical target was 4.5 cc and the median peripheral dose was 20 Gy,for the lung tumors. For the chest wall/pleura tumors, the median volume of the clinical target was 40 cc and the median peripheral dose was 20 Gy. Conventional fractionated conformal radiation therapy (CRT) followed SRS in 10 tumors. Of twenty-one tumors eligible for evaluation, there were 13 CRs, 6PRs, and 2 NCs. Duration of local control ranged from 0.6 to 82 months with a median of 8 months. Immediate palliation was obtained in most symptomatic patients. Interstitial changes in the lung were limited. Autopsy performed for two patients revealed remarkable histologic effects with minimal injuries to the lung. The geometric accuracy of MVCT-assisted SRS appeared to enhance the clinical efficacy and safety of treatment to thoracic malignancies.