Compass验证系统与Oncentra治疗计划系统剂量体积直方图参数差异分析

Difference analysis of dose volume histogram parameters between Compass verification system and Oncentra treatment planning system

目的:比较Compass验证系统与Oncentra治疗计划系统之间剂量体积直方图(DVH)参数差异。方法:随机选取11例胸部肿瘤和10例头颈肿瘤的计划,计划数据由Oncentra传出,导入到Compass系统中,比较两个系统间的靶区和危及器官DVH参数的差异,胸部肿瘤DVH评估参数:肺的5、10、20 Gy受量体积(Lung_V_5、Lung_V_(10)、Lung_V_(20)),肺平均剂量(Lung_mean),脊髓最大量(Cord_D_(Max))和2%体积受量(Cord_D_2),靶区95%体积受量(PTV_D_(95));头颈部肿瘤DVH参数:脊髓最大量(Cord_D_(Max))和2%体积受量(Cord_D_2),左右晶体最大量(Lens_L_D_(max)、Lens_R_D_(max))和2%体积受量(Lens_L_D_2、Lens_R_D_2),左右腮腺平均量(Parotid_L_Mean、Parotid_R_Mean)和50%体积受量(Parotid_L_D_(50)、Parotid_R_D_(50)),脑干最大量(Stem_D_(max))和2%体积受量(Stem_D_2),靶区95%体积受量(PTV_D_(95))。结果:对两系统DVH参数比较,导入到Compass系统中后,胸部肿瘤计划Lung_V_(10)、Lung_V_(20)、Cord_D_(max)和Cord_D_2均显著变大,差异在1%左右;头颈部肿瘤计划:Cord_D_(Max)、Cord_D_2、Lens_L_D_(max)、Lens_R_D_(max)、Parotid_L_Mean、Parotid_R_Mean、Stem_D_(max)、Stem_D_2变大,有统计学意义,其中Cord_D_(Max)、Lens_L_D_(max)、Lens_R_D_(max)、Stem_D_(max)离散程度要高于Cord_D_2、Stem_D_2,所有计划靶区剂量在两系统间差异非常小。结论:两个不同系统按照DICOM协议可以传输剂量数据,但导入新系统中,因为勾画轮廓内剂量格点定义等原因,DVH都有一定的差异,而这个差异不论是否有统计学意义,其差值都非常小,在临床可接受范围内,但在评估计划时仍然需要注意其改变。对于串联器官建议使用体积剂量来比较两系统间的差异。

Objective To compare the difference of the dose volume histogram（DVH） parameters between Compass verification system and Oncentra treatment planning system. Methods Totally, 11 thoracic cancer plans and 10 plans of head and neck cancers were randomly selected. The plan data were transferred from Oncentra to Compass system, and the differences in DVH parameters of target volumes and organs at risk were compared between the two systems. The DVH comparison parameters for thoracic cancer included the lung volumes receiving the doses of 5 Gy, 10 Gy and 20 Gy（Lung_V_5, Lung_V_（10）, Lung_V_（20））, the mean dose for lungs, the maximum dose for cord（Cord_D_（Max））, 2% volume dose for cord（Cord_D_2） and 95% volume dose for target volume（PTV_D_（95））. The DVH comparison parameters for head and neck cancers included Cord_D_（Max）and Cord_D_2, the maximum dose for left and right lens（Lens_L_D_（max）, Lens_R_D_（max））, 2%volume dose for left and right lens（Lens_L_D_2, Lens_R_D_2）, the mean dose for left and right parotid（Parotid_L_Mean,Parotid_R_Mean）, 50% volume dose for left and right parotid（Parotid_L_D_（50）, Parotid_R_D_（50））, the maximum dose of brain stem（Stem_D_（max））, 2% volume dose for brain stem（Stem_D_2） and PTV_D_（95）. Results After the data were imported to Compass system, Lung_V_（10）, Lung_V_（20）, Cord_D_（max）and Cord_D_2in thoracic tumor plans were significantly increased, with about 1% differences. For the plans of head and neck cancers, Cord_D_（Max）, Cord_D_2, Lens_L_D_（max）, Lens_R_D_（max）,Parotid_L_Mean, Parotid_R_Mean,Stem_D_（max）and Stem_D_2became larger in the Compass system, with statistical significance; Cord_D_（Max）, Lens_L_D_（max）, Lens_R_D_（max）, Stem_D_（max）were more discrete than Cord_D_2, Stem_D_2; the differences of target volumes between the two systems were very small. Conclusion Even though the two different systems can transfer dose data based on DICOM protocol, the different definition of dose grids in delineated regions of interest leads to some differences in DVH values between the two systems. The differences with or without statistical significance are very small and acceptable. The small changes are needed be given attention for plan evaluation. For the serial organs at risk, volume dose is recommended to compare the difference between the two systems.