Matsutani M, Nakamura O, Nagashima T, Asai A, Fujimaki T, Tanaka H, Nakamura M, Ueki K, Tanaka Y, Matsuda T
Department of Neurosurgery, Tokyo Metropolitan Komagome Hospital, Japan.
Acta Neurochir (Wien). 1994;131(1-2):80-90. doi: 10.1007/BF01401457.
In radiation therapy for malignant brain tumours, the dose of radiation that can be safely delivered to a tumour is limited by the radiation tolerance of the adjacent normal brain tissue. Among various radiation modalities to produce local tumour eradication without unacceptable complications, we chose a large, single irradiation dose during the operation (intra-operative radiation therapy, IORT). In contrast to X-ray or Cobalt-60 gamma ray irradiation, IORT with a high-energy electron beam delivered by the Shimadzu 20 MeV betatron provides acceptable dose homogeneity with rapid fall-off of the radiation dose beyond the treatment volume. Thus, IORT has the advantage of precise demarcation of the target volume, minimum damage to surrounding normal tissues, and a high absorbed target dose (15-25 Gy in 5-10 min). On the basis of our experience with 170 patients treated by IORT, we established the treatment indications and method in patients with malignant brain tumours. IORT with a dose of 15-25 Gy was delivered to widely resected tumours followed by external radiation therapy. No acute or subacute complications were observed. Treatment results of 30 patients with glioblastoma treated by IORT (mean 18.3 Gy) combined with external radiation therapy (mean 58.5 Gy) resulted in a median survival of 119 weeks and a 2-year survival rate of 61%.
在恶性脑肿瘤的放射治疗中，能够安全地给予肿瘤的辐射剂量受到相邻正常脑组织辐射耐受性的限制。在各种能实现局部肿瘤根除且无不可接受并发症的放射治疗方式中，我们选择了在手术期间给予单次大剂量照射（术中放射治疗，IORT）。与X射线或钴 - 60伽马射线照射不同，由岛津20兆电子伏特电子感应加速器提供的高能电子束进行的IORT，可在治疗体积之外实现可接受的剂量均匀性以及辐射剂量的快速衰减。因此，IORT具有精确划定靶体积、对周围正常组织损伤最小以及靶区吸收剂量高（5 - 10分钟内15 - 25 Gy）的优势。基于我们对170例接受IORT治疗患者的经验，我们确立了恶性脑肿瘤患者的治疗适应证和方法。对广泛切除的肿瘤给予15 - 25 Gy剂量的IORT，随后进行外照射放疗。未观察到急性或亚急性并发症。30例接受IORT（平均18.3 Gy）联合外照射放疗（平均58.5 Gy）治疗的胶质母细胞瘤患者的治疗结果显示，中位生存期为119周，2年生存率为61%。
