Kasai Yuki, Fukuyama Yukihide, Terashima Hiromi, Nakamura Katsumasa, Sasaki Tomonari
Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka City, Fukuoka, 812-8582, Japan.
Department of Radiology, Harasanshin Hospital, 1-8 Taihakumachi, Hakata-ku, Fukuoka City, Fukuoka, 812-0033, Japan.
J Appl Clin Med Phys. 2019 Feb;20(2):129-135. doi: 10.1002/acm2.12540. Epub 2019 Feb 5.
TomoDirect has been reported to have some advantages over TomoHelical in delivering total body irradiation (TBI). This study aimed to investigate the relationships between the number of ports and the dose evaluation indices in low-dose TBI in TomoDirect mode using 2-12 ports and to compare these data with those for the TomoHelical mode in a simulation study. Thirteen patients underwent low-dose TBI in TomoHelical mode from June 2015 to June 2016. We used the same computed tomography data sets for these patients to create new treatment plans for upper-body parts using TomoDirect mode with 2-12 beam angles as well as TomoHelical mode. The prescription was 4 Gy in two equal fractions. For the TomoDirect data, we generated plans with 2-12 ports with approximately equally spaced angles; the modulation factor, field width, and pitch were 2.0, 5.0 cm, and 0.500, respectively. For the TomoHelical plans, the modulation factor, field width, and pitch were 2.0, 5.0 cm, and 0.397, respectively. D2, D98, D50, and the homogeneity index (HI) were evaluated to compare TomoDirect plans having 2-12 ports with the TomoHelical plan. Using TomoDirect plans, D2 with four ports or fewer, D98 with 10 ports or fewer, D50 with four ports or fewer and HI with five ports or fewer showed statistically significantly worse results than the TomoHelical plan. With the TomoDirect plans, D2 with seven ports or more, D50 with eight ports or more, and HI with eight ports or more showed statistically significant improvement compared with the TomoHelical plan. All of the dose evaluation indices of the TomoDirect plans showed a tendency to improve as the number of ports increased. TomoDirect plans showed statistically significant improvement of D2, D50, and HI compared with the TomoHelical plan. Therefore, we conclude that TomoDirect can provide better dose distribution in low-dose TBI with TomoTherapy.
据报道，在进行全身照射（TBI）时，TomoDirect相较于TomoHelical具有一些优势。本研究旨在调查在TomoDirect模式下使用2至12个射野进行低剂量TBI时，射野数量与剂量评估指标之间的关系，并在模拟研究中将这些数据与TomoHelical模式的数据进行比较。2015年6月至2016年6月期间，13例患者接受了TomoHelical模式下的低剂量TBI。我们使用这些患者相同的计算机断层扫描数据集，以2至12个射野角度创建了TomoDirect模式以及TomoHelical模式下上身部位的新治疗计划。处方剂量为4 Gy，分两次等量给予。对于TomoDirect数据，我们生成了射野角度近似等间距的2至12个射野的计划；调制因子、射野宽度和螺距分别为2.0、5.0 cm和0.500。对于TomoHelical计划，调制因子、射野宽度和螺距分别为2.0、5.0 cm和0.397。评估D2、D98、D50和均匀性指数（HI），以比较具有2至12个射野的TomoDirect计划与TomoHelical计划。使用TomoDirect计划时，4个或更少射野的D2、10个或更少射野的D98、4个或更少射野的D50以及5个或更少射野的HI显示出比TomoHelical计划在统计学上显著更差的结果。对于TomoDirect计划，7个或更多射野的D2、8个或更多射野的D50以及8个或更多射野的HI与TomoHelical计划相比在统计学上有显著改善。TomoDirect计划的所有剂量评估指标均显示出随着射野数量增加而改善的趋势。与TomoHelical计划相比，TomoDirect计划的D2、D50和HI在统计学上有显著改善。因此，我们得出结论，在TomoTherapy系统进行低剂量TBI时，TomoDirect可以提供更好的剂量分布。
Zotero 插件
