Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid development.However,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be sol...Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid development.However,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be solved.Patient-specific block collimators(PSBCs),which can block unnecessary doses,play a crucial role in passive scattering delivery technology but are rarely used in spot scanning.One objective of this study is to investigate the lateral penumbra variations of intensity-modulated spot scanning with and without a PSBC.For fields with varying degrees of sharpness and at varying depths in a water phantom,the lateral penumbral widths were calculated using a Monte Carlo-based dose engine from RayStation 6.The results suggest that the lateral penumbral widths can be reduced by more than 30%for uniform target volumes,regardless of whether a range-shifter is used,and that the maximum dose beyond the field edges can be reduced significantly.The results of patient cases show that the doses in organs-at-risk near the edge of the target volume decrease if a PSBC is implemented.This study demonstrates that intensity-modulated spot scanning with a PSBC can effectively reduce the lateral penumbra and block unnecessary doses and is therefore promising for clinical applications in spot-scanning proton therapy.展开更多
Proton therapy is the most advanced radiotherapy approach in the world,and causes less damage to normal human tissue than traditional radiotherapy.Because the treatment process produces a high-energy proton beam,the p...Proton therapy is the most advanced radiotherapy approach in the world,and causes less damage to normal human tissue than traditional radiotherapy.Because the treatment process produces a high-energy proton beam,the personnel safety interlock system mainly considers measures to protect personnel from radiation hazards during beam preparation and the beam release process.Unlike other safety interlock systems,the personnel safety interlock system designed in this study focuses on the safety and stability of the system itself.The hardware and software of important interlock control loops are designed and developed according to the requirements of Safety Integrity Level 3 specified by IEC61508.A set of redundant ring networks was developed to ensure that damage to a certain network line does not affect the normal operation of the system.A set of friendly operation interfaces and data storage systems were developed to ensure that the operator can monitor the data in real time and trace the data.The personnel safety interlock system mainly includes a beam enabling function,clearance function,and emergency stop function.The system was put into actual use and successfully ensured personnel safety.展开更多
基金supported by the Key Program of the 13th Five-Year Plan,the Hefei Institutes of Physical Science of the Chinese Academy of Sciences(No.KP-2017-24)
文摘Intensity-modulated proton therapy(IMPT)is becoming essential for proton therapy and is under rapid development.However,for IMPT,the lateral penumbra of the spot-scanning proton beam is still an urgent issue to be solved.Patient-specific block collimators(PSBCs),which can block unnecessary doses,play a crucial role in passive scattering delivery technology but are rarely used in spot scanning.One objective of this study is to investigate the lateral penumbra variations of intensity-modulated spot scanning with and without a PSBC.For fields with varying degrees of sharpness and at varying depths in a water phantom,the lateral penumbral widths were calculated using a Monte Carlo-based dose engine from RayStation 6.The results suggest that the lateral penumbral widths can be reduced by more than 30%for uniform target volumes,regardless of whether a range-shifter is used,and that the maximum dose beyond the field edges can be reduced significantly.The results of patient cases show that the doses in organs-at-risk near the edge of the target volume decrease if a PSBC is implemented.This study demonstrates that intensity-modulated spot scanning with a PSBC can effectively reduce the lateral penumbra and block unnecessary doses and is therefore promising for clinical applications in spot-scanning proton therapy.
文摘Proton therapy is the most advanced radiotherapy approach in the world,and causes less damage to normal human tissue than traditional radiotherapy.Because the treatment process produces a high-energy proton beam,the personnel safety interlock system mainly considers measures to protect personnel from radiation hazards during beam preparation and the beam release process.Unlike other safety interlock systems,the personnel safety interlock system designed in this study focuses on the safety and stability of the system itself.The hardware and software of important interlock control loops are designed and developed according to the requirements of Safety Integrity Level 3 specified by IEC61508.A set of redundant ring networks was developed to ensure that damage to a certain network line does not affect the normal operation of the system.A set of friendly operation interfaces and data storage systems were developed to ensure that the operator can monitor the data in real time and trace the data.The personnel safety interlock system mainly includes a beam enabling function,clearance function,and emergency stop function.The system was put into actual use and successfully ensured personnel safety.
