Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Sha...Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Shanghai.The synchrotron,beam delivery system,and other technical systems were commissioned and reached their expected performances.After a clinical trial of 47 patients was finished,the proton therapy facility obtained a registration certificate from the National Medical Products Administration.The characteristics of the accelerator and treatment systems are described in this article.展开更多
The spatial resolution of a commercial two-dimensional(2D)ionization chamber(IC)array is limited by the size of the individual detector and the center-to-center distance between sensors.For dose distributions with are...The spatial resolution of a commercial two-dimensional(2D)ionization chamber(IC)array is limited by the size of the individual detector and the center-to-center distance between sensors.For dose distributions with areas of steep dose gradients,inter-detector dose values are derived by the interpolation of nearby detector readings in the conventional mathematical interpolation of 2D IC array measurements.This may introduce significant errors,particularly in proton spot scanning radiotherapy.In this study,by combining logfile-based reconstructed dose values and detector measurements with the Laplacian pyramid image blending method,a novel method is proposed to obtain a reformatted dose distribution that provides an improved estimation of the delivered dose distribution with high spatial resolution.Meanwhile,the similarity between the measured original data and the downsampled logfilebased reconstructed dose is regarded as the confidence of the reformatted dose distribution.Furthermore,we quantify the performance benefits of this new approach by directly comparing the reformatted dose distributions with 2D IC array detector mathematically interpolated measurements and original low-resolution measurements.The result shows that this new method is better than the mathematical interpolation and achieves gamma pass rates similar to those of the original low-resolution measurements.The reformatted dose distributions generally yield a confidence exceeding 95%.展开更多
文摘Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Shanghai.The synchrotron,beam delivery system,and other technical systems were commissioned and reached their expected performances.After a clinical trial of 47 patients was finished,the proton therapy facility obtained a registration certificate from the National Medical Products Administration.The characteristics of the accelerator and treatment systems are described in this article.
文摘The spatial resolution of a commercial two-dimensional(2D)ionization chamber(IC)array is limited by the size of the individual detector and the center-to-center distance between sensors.For dose distributions with areas of steep dose gradients,inter-detector dose values are derived by the interpolation of nearby detector readings in the conventional mathematical interpolation of 2D IC array measurements.This may introduce significant errors,particularly in proton spot scanning radiotherapy.In this study,by combining logfile-based reconstructed dose values and detector measurements with the Laplacian pyramid image blending method,a novel method is proposed to obtain a reformatted dose distribution that provides an improved estimation of the delivered dose distribution with high spatial resolution.Meanwhile,the similarity between the measured original data and the downsampled logfilebased reconstructed dose is regarded as the confidence of the reformatted dose distribution.Furthermore,we quantify the performance benefits of this new approach by directly comparing the reformatted dose distributions with 2D IC array detector mathematically interpolated measurements and original low-resolution measurements.The result shows that this new method is better than the mathematical interpolation and achieves gamma pass rates similar to those of the original low-resolution measurements.The reformatted dose distributions generally yield a confidence exceeding 95%.
