摘要
目的网格尺寸作为放疗计划设计的重要参数,能够直接影响放疗计划的计算精度。本研究探讨网格尺寸对不同部位肿瘤放疗计划精确性的影响,为临床放疗计划设计时网格尺寸的选择提供参考。方法随机选择中山大学附属第五医院肿瘤放疗中心2015-06-01-2016-06-30收治的头颈部、胸部、腹部和四肢肿瘤各20例患者作为研究对象,使用Raystation计划设计系统,在仅改变网格尺寸的情况下,分别选择1、2、3、4和5mm网格行计划设计。在95%PTV体积达到95%的处方剂量下,以1 mm网格为参考,与2~5 mm网格计算的剂量-体积曲线(dose-volume histogram,DVH)行相对剂量差比较。同时,采用三维剂量验证方式对每个放疗计划行γ因子验证,并记录计算耗时。结果(1)相对剂量差结果显示,头颈部肿瘤以2mm网格计算时,靶区和脊髓DVH相对剂量差均<1%,腮腺为(1.07±0.09)%;以4和5mm网格计算,靶区和危及器官均>3%。胸、腹部肿瘤以2和3mm网格计算,靶区和危及器官均<1%,腹部以4mm网格计算的危及器官均<1%,靶区为(1.81±0.21)%;胸部以4和5mm计算,靶区和危及器官相对剂量差均>1%。四肢肿瘤以5mm网格计算的相符剂量差为(0.17±0.11)%。(2)γ因子验证结果显示,1~3mm网格4个部位肿瘤的γ因子合格率均>90%,差异有统计学意义,P<0.05;γ因子平均通过率均>90%(P<0.05),但头颈部肿瘤以4mm网格计算平均通过率为(86.6±3.4)%。(3)计算耗时,1mm网格计算耗时最大,2~5mm网格计算耗时降低,效率明显提高。结论放疗计划网格选择,头颈部肿瘤建议使用2mm网格,胸腹部肿瘤建议使用2~3mm网格,四肢肿瘤建议使用4mm网格。
OBJECTIVE Grid size, as an essential factor, can affect the precise of calculation result directly. The aim of this study was explore the effects of different grids on the precise radiotherapy plan designing for various cancers, and to provide basis for clinical radiotherapy. METHODS Total 20 head and neck neoplasms, 20 thoracic neoplasms, 20 abdominal neoplasms and 20 extremity malignant tumors were choose randomly, and the Raystation treatment plan system （TPS） was used to design the plans by only altering the calculation grid from 1 mm to 5 mm. The 95G prescription dose was deliverd to the 95G volume of target in each plan, and the relatively differential dose of the DVHs between test case and reference case were compared. The verification of γ factor had been analyzed for each radiotherapy plan. RESULTS The relatively differential dose： for the head and neck neoplasms, the target and spinal cord was below 1% which was calculated by 2 mm grid, and the parotid glands was （1.07±0.09）%. The target and OARs which were calculated by 4 and 5 mm grids were above 3 %. For the thoracic neoplasms and abdominal neoplasms, the targets and the OARs were under 1 %, which were calculated by 2 and 3 mm grids. The OAR of abdominal neoplasms were inferior to 1% with 4 mm gird, and only the target was （1.81±0.21）%. While, the thoracic neoplasms with 4 and 5 mm girds, no matter targets or OARs, would exceed the 1%. For the extremity malignant tumors, the coarsest girds （5 mm） would get the ideal result, and the result was （0.17±0.11）%. For the qualification rate of γ： the calculation result of 1-3 mm grids were above 900//00 （P〈0.05）. For the passing rate of y, all of the calculation results were above 90- （P%0.05）, except the head and neck neoplasms with 4 mm grid（86.6 ± 3.4） %. For the computational efficiency： A lot of time would be taken on calculating by 1 mm grid, and 2--5 mm grids took much less time for calculation. CONCLUSIONS It is recommended that the best grid for the head
出处
《中华肿瘤防治杂志》
CAS
北大核心
2017年第20期1465-1468,共4页
Chinese Journal of Cancer Prevention and Treatment
