Mani Karthick Raj, Upadhayay Sagar, Das K J Maria
Research and Development Centre, Bharathiar University, Tamilnadu, India.
Radiation Oncology, Kathmandu Cancer Center, Bhaktapur, Nepal.
Radiat Oncol J. 2017 Mar;35(1):90-100. doi: 10.3857/roj.2016.02054. Epub 2017 Mar 31.
To Study the dosimetric advantage of the Jaw tracking technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for Head and Neck Cancers.
We retrospectively selected 10 previously treated head and neck cancer patients stage (T1/T2, N1, M0) in this study. All the patients were planned for IMRT and VMAT with simultaneous integrated boost technique. IMRT and VMAT plans were performed with jaw tracking (JT) and with static jaw (SJ) technique by keeping the same constraints and priorities for a particular patient. Target conformity, dose to the critical structures and low dose volumes were recorded and analyzed for IMRT and VMAT plans with and without JT for all the patients.
The conformity index average of all patients followed by standard deviation ([Formula: see text] ± [Formula: see text]) of the JT-IMRT, SJ-IMRT, JT-VMAT, and SJ-VMAT were 1.72 ± 0.56, 1.67 ± 0.57, 1.83 ± 0.65, and 1.85 ± 0.64, and homogeneity index were 0.059 ± 0.05, 0.064 ± 0.05, 0.064 ± 0.04, and 0.064 ± 0.05. JT-IMRT shows significant mean reduction in right parotid and left parotid shows of 7.64% (p < 0.001) and 7.45% (p < 0.001) compare to SJ-IMRT. JT-IMRT plans also shows considerable dose reduction to thyroid, inferior constrictors, spinal cord and brainstem compared to the SJ-IMRT plans.
Significant dose reductions were observed for critical structure in the JT-IMRT compared to SJ-IMRT technique. In JT-VMAT plans dose reduction to the critical structure were not significant compared to the SJ-IMRT due to relatively lesser monitor units.
研究颌骨跟踪技术在头颈部癌调强放疗（IMRT）和容积调强弧形放疗（VMAT）中的剂量学优势。
本研究回顾性选取了10例先前接受治疗的头颈部癌患者（T1/T2期，N1，M0）。所有患者均采用同步整合加量技术进行IMRT和VMAT计划。对特定患者，在保持相同约束条件和优先级的情况下，分别采用颌骨跟踪（JT）技术和静态颌骨（SJ）技术进行IMRT和VMAT计划。记录并分析所有患者在有无JT情况下的IMRT和VMAT计划的靶区适形度、关键结构剂量及低剂量体积。
JT-IMRT、SJ-IMRT、JT-VMAT和SJ-VMAT的所有患者的适形指数平均值（标准差为[公式：见原文]±[公式：见原文]）分别为1.72±0.56、1.67±0.57、1.83±0.65和1.85±0.64，均匀性指数分别为0.059±0.05、0.064±0.05、0.064±0.04和0.064±0.05。与SJ-IMRT相比，JT-IMRT显示右侧腮腺和左侧腮腺的平均剂量显著降低，分别为7.64%（p<0.001）和7.45%（p<0.001）。与SJ-IMRT计划相比，JT-IMRT计划还显示甲状腺、下咽缩肌、脊髓和脑干的剂量有相当程度的降低。
与SJ-IMRT技术相比，JT-IMRT中关键结构的剂量显著降低。在JT-VMAT计划中，由于监测单位相对较少，与SJ-IMRT相比，关键结构的剂量降低不显著。
