摘要
目的通过对聚甲基丙烯酸甲酯(PMMA)模体行离线模式下PET/CT显像,探讨PET-边界验证方法(PET-RV)用于定量分析质子放疗精准性的可行性。方法在PMMA模体上分别给予2 Gy和4 Gy的照射剂量,对每个剂量组根据临床靶区(CTV)的不同,以2.5 cm为步进分别设计7个照射深度组(5.0、7.5、10.0、12.5、15.0、17.5、20.0 cm),共14个照射计划(14组照射野)。以能量在48~221 MeV之间的质子束照射,照射结束后10 min左右进行PET/CT显像。对PET/CT数据分别进行图像配准、平滑和约化等预处理,然后利用Raystation PET-RV软件对图像进行感兴趣区(ROI)的确定和采样线的抽提,通过生成的预测感生放射性活度与实际采集感生放射性活度采样线计算ΔR50,即2条曲线末端在最大预测感生放射性活度最大值下降一半(V50)处对应的空间位置差异。结果每个照射野的ROI均为5.0 cm×5.0 cm×2.5 cm的立方体,采样线在其内间隔3 mm均匀分布,共得到289组采样线。14组数据经分析后得到的ΔR50(深度差异)均值都处于-1~1 mm之间。结论离线模式下PET/CT显像示PET-RV算法对PMMA模体质子放疗空间位置差异的验证精度在1 mm之内,可以满足后期对临床病例分析的精度要求。
Objective To test the usefulness of PET-range verification(RV)method for proton radiation accuracy verification in poly(methyl methacrylate)(PMMA)phantom using off-line PET/CT scanning.Methods Proton irradiation dose of 2 Gy and 4 Gy were delivered in PMMA phantom.Given the difference of clinical target volume(CTV),7 subgroups with different depth(5.0,7.5,10.0,12.5,15.0,17.5,20.0 cm)were set for each dose(14 radiation plans or radiation fields).PET/CT scan was performed 10 min after irradiation of 48-221 MeV proton beam.A co-registration between CT from treatment planning system and PET/CT was performed,as well as the smoothing and normalization of PET/CT data.The region of interest(ROI)and profile lines were drawn with the Raystation PET-RV software.The predictive induced radioactivity and the measured induced radioactivity profile lines were analyzed to evaluate theΔR50,namely,the error at the position corresponding to 50%of the maximum predictive induced radioactivity at the end of both curves.Results The size of each ROI was 5.0 cm×5.0 cm×2.5 cm.Profile lines were evenly distributed with the interval of 3 mm,and totally 289 pairs of profile lines were drew.The 2 Gy-and 4 Gy-dose groups yielded similar mean depth errors(ΔR50 between 1 mm and-1 mm with a standard deviation<1 mm).Conclusions The off-line PET/CT scanning of PMMA phantom reveals a good agreement between predicted and measured PET data,with error of±1 mm.The PET-RV method can be extended to clinical cases′verification in human body treatment with further investigation.
作者
张建岗
张俊昱
卢艳
盛尹祥子
任炜
施磊俊
孙筠
章英剑
Hsi Wenchien
周荣
蒋国梁
陆嘉德
程竞仪
Zhang Jiangang;Zhang Junyu;Lu Yan;Sheng Yinxiangzi;Ren Wei;Shi Leijun;Sun Yun;Zhang Yingjian;Hsi Wenchien;Zhou Rong;Jiang Guoliang;Lu Jiade;Cheng Jingyi(Department of Nuclear Medicine,Shanghai Proton and Heavy Ion Center,Shanghai Engineering Research Center of Proton and Heavy Ion Radiation Therapy,Shanghai 201321,China;School of Physics,Sichuan University,Chengdu 610065,China;Department of Medical Physics,Shanghai Proton and Heavy Ion Center,Shanghai Engineering Research Center of Proton and Heavy Ion Radiation Therapy,Shanghai 201321,China;Department of Nuclear Medicine,Shanghai Proton and Heavy Ion Center,Fudan University Cancer Hospital,Shanghai 201321,China;Center for Biomedical Imaging,Fudan University,Shanghai 200032,China;Shanghai Engineering Research Center of Molecular Imaging Probes,Shanghai 200032,China;University Florida Health Proton Therapy Institue and Radiation Oncology of University,Jacksonville,Florida FL32819,US;Department of Radiotherapy,Shanghai Proton and Heavy Ion Center,Shanghai Engineering Research Center of Proton and Heavy Ion Radiation Therapy,Shanghai 201321,China)
出处
《中华核医学与分子影像杂志》
CAS
北大核心
2020年第10期603-608,共6页
Chinese Journal of Nuclear Medicine and Molecular Imaging
基金
国家自然科学基金(21501029)
上海市卫生和计划生育委员会科研课题计划(201640196)
