在 TMI/TMLI 中采用新的剂量分割策略的可行性。
Feasibility of a novel dose fractionation strategy in TMI/TMLI.
机构信息
Department of Radiation and Medical Oncology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
Hubei Radiotherapy Quality Control Center, Wuhan University, Wuhan, Hubei, China.
出版信息
Radiat Oncol. 2018 Dec 17;13(1):248. doi: 10.1186/s13014-018-1201-0.
BACKGROUND
To report our experience in planning and delivering total marrow irradiation (TMI) and total marrow and lymphatic irradiation (TMLI) in patients with hematologic malignancies.
METHODS
Twenty-seven patients undergoing bone marrow transplantation were treated with TMI/TMLI using Helical Tomotherapy (HT). All skeletal bones exclusion of the mandible comprised the treatment target volume and, for TMLI, lymph node chains, liver, spleen and/or brain were also included according to the clinical indication. Planned dose of 8Gy in 2 fractions was delivered over 1 day for TMI while 10Gy in 2 fractions BID was used for TMLI. Organs at risk (OAR) contoured included the brain, brainstem, lens, eyes, optic nerves, parotids, oral cavity, lungs, heart, liver, kidneys, stomach, small bowel, bladder and rectum. In particular, a simple method to avoid hot or cold doses in the overlapping region was implemented and the plan sum was adopted to evaluate dose inhomogeneity. Furthermore, setup errors from 54 treatments were summarized to gauge the effectiveness of immobilization.
RESULTS
During the TMI/TMLI treatment, no acute adverse effects occurred during the radiation treatment. Two patients suffered nausea or vomiting right after radiation course. For the 9 patients treated with TMI, the median dose reduction of major organs varied 30-65% of the prescribed dose, substantially lower than the traditional total body irradiation (TBI). Meanwhile, average biological equivalent doses to OARs with 8Gy/2F TMI approach were not different from the conventional 12Gy/6F TMI approach. In the dose junction region, the 93% of PTV was covered by the prescribed dose without obvious hotspots. For the 27 patients, the overall setup corrections were lower than 3 mm except those in the SI direction for abdomen-pelvis region, demonstrating excellent immobilization.
CONCLUSION
The present study confirmed the technical feasibility of HT-based TMI/TMLI delivering 8-10Gy in 2 fractions over 1 day. For patients undergoing hematopoietic cell transplantation the proposed 8Gy/2F TMI (or 10Gy/2F TMLI) strategy may be a novel approach to improve delivery efficiency, increase effective radiation dose to target while maintaining low risk of severe organ toxicities.
背景
报告我们在血液病患者中进行全身骨髓照射（TMI）和全身骨髓及淋巴照射（TMLI）计划和实施的经验。
方法
27 例接受骨髓移植的患者采用螺旋断层放疗（HT）进行 TMI/TMLI 治疗。所有骨骼（不包括下颌骨）构成治疗靶区，根据临床指征，还包括淋巴结链、肝、脾和/或脑。TMI 采用 2 次分割 8Gy 方案，TMLI 采用 2 次分割 BID 10Gy 方案。勾画的危及器官（OAR）包括脑、脑干、晶状体、眼睛、视神经、腮腺、口腔、肺、心脏、肝、肾、胃、小肠、膀胱和直肠。特别是，采用了一种简单的方法来避免重叠区域的冷或热点剂量，并采用计划和来评估剂量不均匀性。此外，还总结了 54 次治疗的摆位误差，以评估固定的有效性。
结果
在 TMI/TMLI 治疗期间，放疗过程中没有发生急性不良反应。有 2 例患者在放疗后立即出现恶心或呕吐。对于接受 TMI 治疗的 9 例患者，主要器官的中位剂量减少了 30-65%的处方剂量，明显低于传统的全身照射（TBI）。同时，8Gy/2F TMI 对 OAR 的平均生物等效剂量与传统的 12Gy/6F TMI 方法无差异。在剂量交界处，93%的 PTV 被规定剂量覆盖，没有明显的热点。对于 27 例患者，除腹部-骨盆区域 SI 方向外，总体摆位误差均小于 3mm，固定效果极佳。
结论
本研究证实了基于 HT 的 TMI/TMLI 单次 2 次分割 8-10Gy 的技术可行性。对于接受造血细胞移植的患者，建议采用 8Gy/2F TMI（或 10Gy/2F TMLI）方案，可能是提高输送效率、增加靶区有效辐射剂量同时降低严重器官毒性风险的新方法。
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