Background and Aim: Irradiation methods such as double scattering method and spot scanning method have been used in proton beam treatment devices. In the scattering method, a ridge filter or a range modulation wheel i...Background and Aim: Irradiation methods such as double scattering method and spot scanning method have been used in proton beam treatment devices. In the scattering method, a ridge filter or a range modulation wheel is used to create a spread-out Bragg peak, but the distribution at the patient position may change due to positional deviation of the incident beam. Therefore, assessment of the incident position of the beam is very important even in the scattering method. To investigate the width and distribution of the proton beam before entering the RMW, a radiochromic film was installed at the outlet of the transport pipe and the entrance of the profile-monitoring detector. Methods: In this study, the distributions of the beam at the exit of the transport pipe and the entrance of the monitor detector were measured using films. The beam width was measured from the full width at half maximum of the profile obtained from the distribution. Measurements were conducted every month for 10 months. Results: Beams of widths ranging from 1.82 to 2.30 mm in the horizontal direction and 4.25 to 5.33 mm in the vertical direction were outputted from the exit of the transport pipe. Beams of widths ranging from 2.16 to 2.67 mm in the horizontal direction and 4.06 to 5.31 mm in the vertical direction were outputted from the entrance of the monitor detector. The maximum width fluctuation for 10 months was 0.55 mm in the horizontal direction and 1.26 mm in the vertical direction at the entrance of the monitor detector. Conclusions: The distribution was obtained before the proton beam was scattered by the scatterer, and then we propose a method to periodically measure and monitor the changes in the beam distributions every month.展开更多
目的探讨直接数字化X线摄影系统(direct digital radiography,DDR)立位后前住胸片窗宽、窗位与密度值的变化关系,提高DDR立位后前住胸片质量。方法分析400份DDR立位后前位胸片窗宽、窗位与密度值的变化。结果 1窗位固定(1)窗宽降低,密...目的探讨直接数字化X线摄影系统(direct digital radiography,DDR)立位后前住胸片窗宽、窗位与密度值的变化关系,提高DDR立位后前住胸片质量。方法分析400份DDR立位后前位胸片窗宽、窗位与密度值的变化。结果 1窗位固定(1)窗宽降低,密度值升高;(2)窗宽升高,密度值降低;2窗宽固定(1)窗位降低,密度值降低;(2)窗位升高,密度值升高;3窗宽、窗位都降低,密度值升高;4窗宽、窗位都升高,密度值降低;5窗宽升高,窗位降低,密度值降低;6窗宽降低,窗位升高,密度值升高。结论认识DDR立位后前位胸片窗宽、窗位与密度值的关系,对提高其质量有很大价值。展开更多
文摘Background and Aim: Irradiation methods such as double scattering method and spot scanning method have been used in proton beam treatment devices. In the scattering method, a ridge filter or a range modulation wheel is used to create a spread-out Bragg peak, but the distribution at the patient position may change due to positional deviation of the incident beam. Therefore, assessment of the incident position of the beam is very important even in the scattering method. To investigate the width and distribution of the proton beam before entering the RMW, a radiochromic film was installed at the outlet of the transport pipe and the entrance of the profile-monitoring detector. Methods: In this study, the distributions of the beam at the exit of the transport pipe and the entrance of the monitor detector were measured using films. The beam width was measured from the full width at half maximum of the profile obtained from the distribution. Measurements were conducted every month for 10 months. Results: Beams of widths ranging from 1.82 to 2.30 mm in the horizontal direction and 4.25 to 5.33 mm in the vertical direction were outputted from the exit of the transport pipe. Beams of widths ranging from 2.16 to 2.67 mm in the horizontal direction and 4.06 to 5.31 mm in the vertical direction were outputted from the entrance of the monitor detector. The maximum width fluctuation for 10 months was 0.55 mm in the horizontal direction and 1.26 mm in the vertical direction at the entrance of the monitor detector. Conclusions: The distribution was obtained before the proton beam was scattered by the scatterer, and then we propose a method to periodically measure and monitor the changes in the beam distributions every month.
文摘目的探讨直接数字化X线摄影系统(direct digital radiography,DDR)立位后前住胸片窗宽、窗位与密度值的变化关系,提高DDR立位后前住胸片质量。方法分析400份DDR立位后前位胸片窗宽、窗位与密度值的变化。结果 1窗位固定(1)窗宽降低,密度值升高;(2)窗宽升高,密度值降低;2窗宽固定(1)窗位降低,密度值降低;(2)窗位升高,密度值升高;3窗宽、窗位都降低,密度值升高;4窗宽、窗位都升高,密度值降低;5窗宽升高,窗位降低,密度值降低;6窗宽降低,窗位升高,密度值升高。结论认识DDR立位后前位胸片窗宽、窗位与密度值的关系,对提高其质量有很大价值。
