Department of Applied Physics, Karunya Institute of Technology and Sciences, Coimbatore, India.
Department of Oncology, Aster Malabar Institute of Medical Sciences, Calicut, India.
Asian Pac J Cancer Prev. 2022 Apr 1;23(4):1397-1403. doi: 10.31557/APJCP.2022.23.4.1397.
To study the dosimetric importance of Jaw tracking technique in reducing the doses to organs at risk (OAR) while achieving the optimal dose coverage for the target.
We retrospectively selected ten Glioblastoma cases and for each patient, two plans were created namely Static Jaw Technique Dynamic Intensity Modulated Radiotherapy plan and Jaw Tracking Technique D-IMRT plan with 6 MV for Varian Truebeam™ STx machine using Eclipse Treatment planning system. Both plans were analyzed and compared based on various dosimetric parameters for Planning Target Volume (PTV) and OARs. The dose agreement between the Portal dose image prediction and the portal dosimetry measurement was also analysed using gamma analysis criteria of 3%/3mm, 2%/2mm and 1%/1mm of dose distance/distance-to-agreement.
The dosimetric parameters evaluated for both plans showed that most of the parameters gave significant P values, where D50% of PTV showed a mean difference (Δ) of 0.45 with significant P value, 0.0104. Similarly mean dose, D2%, D98%, D80% to PTV, Conformity Index and Conformation number showed Δ values of 0.45, 0.51, 0.41, 0.40, 0.02 and 0.01 with their significant P values as 0.0138, 0.0172, 0.0313, 0.0466, 0.0279, 0.0561 respectively. The Δ values and significant P values obtained among OARs are 0.54;0.0224 for brainstem, 0.54;0.0017 for RT optic nerve, 0.52;0.0001 for LT optic nerve, 0.59;0.0040 for optic chiasm and for the healthy tissues it showed the values with their mean dose, V5 and V30 parameters as 0.19;0.0115, 0.59;0.0067 and 0.25;0.0125 respectively. The JTT plans showed better passing results of gamma analysis criteria when compared to SJT plans.
The findings in the studies emphasize the importance of using JTT technique in the radiotherapy treatment plans as it lowers the risk of acute or late toxicity and secondary radiogenic cancers in patients by reducing the OAR doses and achieves better tumor control.
研究 Jaw tracking 技术在降低危及器官（OAR）剂量的同时实现靶区最佳剂量覆盖的剂量学重要性。
我们回顾性选择了 10 例脑胶质瘤病例，为每位患者创建了两个计划，即静态 Jaw 技术动态强度调制放疗计划和 Jaw Tracking 技术 D-IMRT 计划，使用 Eclipse 治疗计划系统在瓦里安 Truebeam™ STx 机器上使用 6 MV。根据计划靶区（PTV）和 OAR 的各种剂量学参数对这两个计划进行了分析和比较。还使用 3%/3mm、2%/2mm 和 1%/1mm 的剂量距离/剂量-协议符合度伽玛分析标准，分析了门控剂量图像预测与门控剂量测量之间的剂量一致性。
评估这两个计划的剂量学参数表明，大多数参数都有显著的 P 值，其中 PTV 的 D50%显示出 0.45 的平均差异（Δ），具有显著的 P 值，为 0.0104。同样，PTV 的平均剂量、D2%、D98%、D80%、适形指数和适形性，也显示出 0.45、0.51、0.41、0.40、0.02 和 0.01 的Δ值，具有显著的 P 值分别为 0.0138、0.0172、0.0313、0.0466、0.0279 和 0.0561。OAR 之间获得的Δ值和显著 P 值分别为 0.54；0.0224 为脑干，0.54；0.0017 为 RT 视神经，0.52；0.0001 为 LT 视神经，0.59；0.0040 为视交叉，对于健康组织，其值为平均剂量、V5 和 V30 参数，分别为 0.19；0.0115、0.59；0.0067 和 0.25；0.0125。与 SJT 计划相比，JTT 计划的伽玛分析标准通过率更好。
研究结果强调了在放射治疗计划中使用 JTT 技术的重要性，因为它可以通过降低 OAR 剂量来降低患者急性或迟发性毒性和继发性放射致癌的风险，并实现更好的肿瘤控制。
