In heavy ion radiotherapy,secondary particles impact not only on physical dose but also on biological effective dose due to different radiation qualities contributed from different secondary particles.Therefore,it is ...In heavy ion radiotherapy,secondary particles impact not only on physical dose but also on biological effective dose due to different radiation qualities contributed from different secondary particles.Therefore,it is necessary to comprehend the constitutions of carbon-ion pencil beam along its penetration.展开更多
Althoughl physical characteristics of ion beam are well understood,the complex relative biological effectiveness(RBE)prevents it from playing its all the potential clinical advantages.To better predict the RBE in ion-...Althoughl physical characteristics of ion beam are well understood,the complex relative biological effectiveness(RBE)prevents it from playing its all the potential clinical advantages.To better predict the RBE in ion-beam therapy,a novel logistic nanodosimetry model(LNDM)based on the ion cluster size distributions on nanoscale was established.展开更多
The accuracy of dose calculation is of vital importance in treatment planning system(TPS).Taking the low dose envelope of carbon-ion pencil beam into consideration,a novel model,called as double Gaussian-logistic mode...The accuracy of dose calculation is of vital importance in treatment planning system(TPS).Taking the low dose envelope of carbon-ion pencil beam into consideration,a novel model,called as double Gaussian-logistic model,has been proposed to depict the lateral dose distribution of carbon-ion pencil beam in our previous work,where the accuracy of the model was preliminarily verified using both single-spot beam and superposed fields in various cases for carbon-ion pencil beam[1].In this work,virtual spherical target volumes of different sizes in water tank were adopted to testify the superiority of the double Gaussian-logistic modelto the single,double and triple Gaussian models for carbon ion beam further.Based on Monte Carlo(MC)simulation and dose optimization-oriented iterative least square method,comparisons of the dose distributions between the MC simulations and calculations using the single。展开更多
Heavy Ion Medical Machine in Wuwei(HIMM-WW)has already been built.The new facility,with four therapy terminals,can provide carbon-ion beams with energy ranging from 120 to 400 MeV/u.For HIMM-WW,a LETbased approach is ...Heavy Ion Medical Machine in Wuwei(HIMM-WW)has already been built.The new facility,with four therapy terminals,can provide carbon-ion beams with energy ranging from 120 to 400 MeV/u.For HIMM-WW,a LETbased approach is adopted to calculate RBE.Considering the successful application of microdosimetric kinetic model(MKM)and plentiful therapeutic experience in Japan for clinical Carbon-ion therapy,the purpose of this study is to verify the RBE value used in HIMM-WW with microdosimetric approach.展开更多
Tissue equivalent proportional counter(TEPC)[1;2]is widely used for microdosimetric measurements of heavy ion beams,which provide basic data for calculating relative biological effectiveness(RBE).To study the influenc...Tissue equivalent proportional counter(TEPC)[1;2]is widely used for microdosimetric measurements of heavy ion beams,which provide basic data for calculating relative biological effectiveness(RBE).To study the influence of TEPC wall on microdosimetric spectra of heavy ion beams,an ideal TEPC combined with Monte Carlo(MC)simulations was introduced to accurately calculate the microdosimetric spectra at different water equivalent depths of carbon ion beams.Three setups used in Gate-based[3]Monte Carlo simulations are shown in Fig.1,namely the ideal TEPC,general TEPC and the TEPC wall as a water layer with a fixed water equivalent thickness respectively.展开更多
An accurate kernel model is of vital importance for pencil-beam dose algorithm in charged particle therapy using precise spot-scanning beam delivery,in which an accurate depiction of the low dose envelope is especiall...An accurate kernel model is of vital importance for pencil-beam dose algorithm in charged particle therapy using precise spot-scanning beam delivery,in which an accurate depiction of the low dose envelope is especially crucial.Although the dose level of the low dose envelope is under 3 or 4 orders of magnitude to the dose in the beam axis,the superimposed effect cannot be neglected.In many primary versions of treatment planning system(TPS)for proton or carbon ion therapy,two-dimension single Gaussian model is used to calculate the lateral dose distribution of pencil beam in medium[13].However,it was found that the single Gaussian model does not depict adequately the dose contributed from secondary particles especially for low dose envelope.展开更多
文摘In heavy ion radiotherapy,secondary particles impact not only on physical dose but also on biological effective dose due to different radiation qualities contributed from different secondary particles.Therefore,it is necessary to comprehend the constitutions of carbon-ion pencil beam along its penetration.
文摘Althoughl physical characteristics of ion beam are well understood,the complex relative biological effectiveness(RBE)prevents it from playing its all the potential clinical advantages.To better predict the RBE in ion-beam therapy,a novel logistic nanodosimetry model(LNDM)based on the ion cluster size distributions on nanoscale was established.
文摘The accuracy of dose calculation is of vital importance in treatment planning system(TPS).Taking the low dose envelope of carbon-ion pencil beam into consideration,a novel model,called as double Gaussian-logistic model,has been proposed to depict the lateral dose distribution of carbon-ion pencil beam in our previous work,where the accuracy of the model was preliminarily verified using both single-spot beam and superposed fields in various cases for carbon-ion pencil beam[1].In this work,virtual spherical target volumes of different sizes in water tank were adopted to testify the superiority of the double Gaussian-logistic modelto the single,double and triple Gaussian models for carbon ion beam further.Based on Monte Carlo(MC)simulation and dose optimization-oriented iterative least square method,comparisons of the dose distributions between the MC simulations and calculations using the single。
文摘Heavy Ion Medical Machine in Wuwei(HIMM-WW)has already been built.The new facility,with four therapy terminals,can provide carbon-ion beams with energy ranging from 120 to 400 MeV/u.For HIMM-WW,a LETbased approach is adopted to calculate RBE.Considering the successful application of microdosimetric kinetic model(MKM)and plentiful therapeutic experience in Japan for clinical Carbon-ion therapy,the purpose of this study is to verify the RBE value used in HIMM-WW with microdosimetric approach.
文摘Tissue equivalent proportional counter(TEPC)[1;2]is widely used for microdosimetric measurements of heavy ion beams,which provide basic data for calculating relative biological effectiveness(RBE).To study the influence of TEPC wall on microdosimetric spectra of heavy ion beams,an ideal TEPC combined with Monte Carlo(MC)simulations was introduced to accurately calculate the microdosimetric spectra at different water equivalent depths of carbon ion beams.Three setups used in Gate-based[3]Monte Carlo simulations are shown in Fig.1,namely the ideal TEPC,general TEPC and the TEPC wall as a water layer with a fixed water equivalent thickness respectively.
文摘An accurate kernel model is of vital importance for pencil-beam dose algorithm in charged particle therapy using precise spot-scanning beam delivery,in which an accurate depiction of the low dose envelope is especially crucial.Although the dose level of the low dose envelope is under 3 or 4 orders of magnitude to the dose in the beam axis,the superimposed effect cannot be neglected.In many primary versions of treatment planning system(TPS)for proton or carbon ion therapy,two-dimension single Gaussian model is used to calculate the lateral dose distribution of pencil beam in medium[13].However,it was found that the single Gaussian model does not depict adequately the dose contributed from secondary particles especially for low dose envelope.
