Sun Ying, Zhou Guan-Qun, Qi Zhen-Yu, Zhang Li, Huang Shao-Min, Liu Li-Zhi, Li Li, Lin Ai-Hua, Ma Jun
State Key Laboratory of Oncology in Southern China, Department of Radiation Oncology, Cancer Center, Sun Yat-sen University, Guangzhou 510060, People's Republic of China.
BMC Cancer. 2013 Aug 27;13:397. doi: 10.1186/1471-2407-13-397.
To identify the radiation volume effect and significant dosimetric parameters for temporal lobe injury (TLI) and determine the radiation dose tolerance of the temporal lobe (TL) in nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiation therapy (IMRT).
Twenty NPC patients with magnetic resonance imaging (MRI)-diagnosed unilateral TLI were reviewed. Dose-volume data was retrospectively analyzed.
Paired samples t-tests showed all dosimetric parameters significantly correlated with TLI, except the TL volume (TLV) and V₇₅ (the TLV that received ≥75 Gy, P = 0.73 and 0.22, respectively). Receiver operating characteristic (ROC) curves showed V₁₀ and V₂₀ (P = 0.552 and 0.11, respectively) were the only non-significant predictors from V₁₀ to V₇₀ for TLI. D(0.5cc) (dose to 0.5 ml of the TLV) was an independent predictor for TLI (P < 0.001) in multivariate analysis; the area under the ROC curve for D(0.5cc) was 0.843 (P < 0.001), and the cutoff point 69 Gy was deemed as the radiation dose limit. The distribution of high dose 'hot spot' regions and the location of TLI were consistent.
A D0.5cc of 69 Gy may be the dose tolerance of the TL. The risk of TLI was highly dependent on high dose 'hot spots' in the TL; physicians should be cautious of such 'hot spots' in the TL during IMRT treatment plan optimization, review and approval.
识别颞叶损伤（TLI）的放射体积效应和重要剂量学参数，并确定接受调强放射治疗（IMRT）的鼻咽癌（NPC）患者颞叶（TL）的放射剂量耐受性。
回顾了20例经磁共振成像（MRI）诊断为单侧TLI的NPC患者。对剂量体积数据进行回顾性分析。
配对样本t检验显示，除颞叶体积（TLV）和V₇₅（接受≥75 Gy的TLV，P分别为0.73和0.22）外，所有剂量学参数均与TLI显著相关。受试者工作特征（ROC）曲线显示，V₁₀和V₂₀（P分别为0.552和0.11）是从V₁₀到V₇₀中仅有的对TLI无显著预测作用的参数。在多因素分析中，D(0.5cc)（TLV中0.5 ml的剂量）是TLI的独立预测因素（P < 0.001）；D(0.5cc)的ROC曲线下面积为0.843（P < 0.001），截断点69 Gy被视为放射剂量限值。高剂量“热点”区域的分布与TLI的位置一致。
69 Gy的D0.5cc可能是TL的剂量耐受性。TLI的风险高度依赖于TL中的高剂量“热点”；在IMRT治疗计划优化、审查和批准过程中，医生应谨慎对待TL中的此类“热点”。
