调强放射治疗在头颈部肿瘤脉冲式低剂量率放射治疗中的可行性

Feasibility of intensity modulated radiation therapy in pulsed low dose rate radiotherapy for head and neck cancer

目的：头颈部肿瘤复发患者往往面对不能进行手术、再次常规放疗和化疗耐受的问题。据国外研究，脉冲式低剂量率放射治疗是一种有效治疗头颈部复发肿瘤的技术。研究10射野调强放射治疗技术在头颈部肿瘤脉冲式低剂量率放射治疗中的可行性。方法：采用10例头颈部肿瘤病例，放疗靶区体积77c甜～299cm3，按照脉冲式低剂量率放射治疗的细胞超敏反应剂量限值要求，单个射野对靶区最大剂量贡献应小于0．5Gy，进行10个固定射野的调强放射治疗计划设计，计算出单个射野对靶区最大剂量贡献，分析10射野调强技术在头颈部肿瘤脉冲式低剂量率放射治疗中应用的可行性。结果：针对10例头颈部病例设计的脉冲式低剂量率放射治疗计划完全能够满足肿瘤细胞发生超敏反应的剂量限值要求。所有100个射野，单个射野对靶区最大剂量贡献均小于0．4Gy，完全满足小于0．5Gy的剂量限值要求。结论：10射野调强放射治疗技术在头颈部肿瘤脉冲式低剂量率放射治疗中应用是可行的。此技术为头颈部复发肿瘤的治疗提供了一种新选择。

Objective Based on the foreign researches, to study the feasibility of 10-field intensity modulated radiation therapy （IMRT） in pulsed low dose rate radiotherapy for head and neck cancer, because that patients with recurrent head and neck cancer are usually unable to undergo a second surgery and conventional radiotherapy, with lower chemotherapy tolerance, and that foreign researches show that pulsed low dose rate radiotherapy is an effective way to treat recurrent head and neck cancer. Methods Ten patients with head and neck cancer were selected. The target volume ranged from 77 cm3 to 299 cm3. Ten-field IMRT plans were designed in accordance with the dose limit of cell hypersensitivity in pulsed low dose rate radiotherapy, which meant the maximum dose contribution of each field was less than 0.5 Gy. The maximum dose contribution of each field to the target volume was calculated, and the feasibility of 10-field IMRT in pulsed low dose rate radiotherapy for head and neck cancer was analyzed. Results The 10 pulsed low dose rate radiotherapy for head and neck cancer satisfied the dose limits of hypersensitivity developed in cancer cells. All the dose contributions were less than 0.4 Gy, lower than the dose limit of 0.5 Gy. Conclusion Ten-field IMRT is feasible in the pulsed low dose rate radiotherapy for head and neck cancer, providing a new choice for treating recurrent head and neck cancer.