中国癌症杂志2025，Vol.35Issue(5)：457-464,8.DOI:10.19401/j.cnki.1007-3639.2025.05.004
2D脊形滤波器提高碳离子治疗效率的临床可行性研究
Clinical feasibility study of a 2D ripple filter to improve the efficiency of carbon ion therapy
摘要
Abstract
Background and purpose:The ripple filter(RiFi)is a passive energy modulator used in particle beam therapy to broaden the Bragg peak.The 1D-RiFi features a wavy structure that can broaden a monoenergetic carbon ion beam to 3 mm,while the 2D-RiFi employs a two-dimensional groove structure to achieve a 6 mm beam broadening.This study aimed to evaluate the potential advantages of the 2D-RiFi over the 1D-RiFi in terms of dose distribution optimization,treatment efficiency,and organ at risk(OAR)dose control by comparing water phantom and clinical patient plans.Methods:Carbon ion treatment plans were designed for water phantoms and 20 patients using both 1D-RiFi and 2D-RiFi.The water phantom plans targeted a cubic region of interest(80 mm×80 mm×80 mm)at ranges of 95,105,190 and 290 mm.From patients who underwent carbon ion therapy at Shanghai Proton and Heavy Ion Center,20 cases were selected via simple random sampling with computer-generated random numbers,stratified by the proportion of different tumor sites(6 head and neck tumors,4 prostate tumors,4 lung tumors,2 pancreatic tumors,2 liver tumors and 2 shoulder tumors).Key dosimetric metrics,including homogeneity index(HI),conformity index(CI)and clinical target volume(CTV)coverage by 95%prescription dose(V95),were analyzed along with OAR doses.Energy layers,beam time,and irradiation time were compared between the two RiFi types.Statistical analysis was performed using the Wilcoxon rank-sum test,with a significance level of P＜0.05.This study was approved by the ethics committee of Shanghai Proton and Heavy Ion Center(approval number:240311EXP-01).Results:For water phantom plans,the 1D-RiFi plans achieved HI of 0.04±0.01,CI of 1.10±0.03,V95 of 99.92%±0.06%and flatness of 6.52%±0.61%,while the 2D-RiFi plans achieved HI of 0.04±0.01,CI of 1.11±0.04,V95 of 99.92%±0.06%,and flatness of 7.52%±0.81%.The mean doses to the distal and lateral block in 1D-RiFi plans were(1.34 Gy±0.43)Gy[relative biological effectiveness(RBE)]and(0.98±0.05)Gy(RBE),respectively,compared to(1.47±0.33)Gy(RBE)and(0.94±0.03)Gy(RBE)for 2D-RiFi plans.The use of 2D-RiFi reduced the average beam-on time by 43%and the number of energy layers by 48%.For clinical plans,the 1D-RiFi plans had HI of 0.07±0.04,CI of 1.94±0.67,and V95 of 98.81%±1.61%,compared to HI of 0.07±0.05,CI of 1.95±0.70,and V95 of 98.79%±1.69%for the 2D-RiFi plans,with no statistically significant differences(P=0.77,0.65 and 0.66,respectively).OAR mean doses increased slightly with the 2D-RiFi plans(average increase of 0.8%,P=0.62)but remained within clinically acceptable limits.The 2D-RiFi plans reduced energy layers by 45%-50%(average 48%),beam time by 32%-49%(average 44%),and irradiation time by 28%-41%(average 36%).Conclusion:Treatment plans using the 2D-RiFi achieved comparable target coverage to those using the 1D-RiFi,with a slight but clinically acceptable increase in OAR doses.The application of the 2D-RiFi significantly reduced the number of energy layers,beam time and irradiation time in carbon ion therapy,enhancing treatment efficiency.关键词
脊型滤波器/碳离子治疗/剂量学/临床效率/剂量分布优化Key words
Ripple filter/Carbon ion therapy/Dosimetry/Clinical efficiency/Dose distribution optimization分类
医药卫生引用本文复制引用
张利嘉,SCHLEGEL Nicki,盛尹祥子,韩榕城,赵静芳..2D脊形滤波器提高碳离子治疗效率的临床可行性研究[J].中国癌症杂志,2025,35(5):457-464,8.基金项目
上海市卫生健康委员会青年项目(20244Y0049). Shanghai municipal health commission youth program(20244Y0049). （20244Y0049）
