Simulation And Experimental Study Of The Dose Distribution In Treatment System Of The Medical Linear Accelerator

Radiotherapy technology based on electron accelerators has become the main form of radiation therapy.The dose distribution data of the medical electron linear acceleration therapy system is an important basis for formulating treatment plans.In this paper,the new Synergy electron linear accelerator,which was purchased by the Second Hospital of Lanzhou University,was used to carry out a simulation study and an experimental study of the dose distribution of the treatment system.The purpose was to lay the foundation for the next clinical treatment.Theoretical issues such as radiation dose,absorbed dose,and the relationship between radiation therapy are studied,and the radiation field,percent depth dose(PDD),and dose distribution flatness involved in radiotherapy for medical electron linac are studied.Symmetry,etc.are summarized.Based on the structure of Synergy Synergy Linear Accelerator treatment head,a material simulation model was established.The Geant4 program was used to simulate the dose distribution of the treatment head system.The electron energy was 6MeV and 10 MeV,and the field was5 cm x 5cm and 10 cm x Percentage depth dose distribution curve and dose transverse distribution curve in tissue equivalent tank under 10 cm condition.Based on the medical science synergy electron linear accelerator treatment system,a German PTW three-dimensional water tank and a finger-type ionization chamber with a sensitive volume of 0.125 cm3 were used to complete a 100% depth dose distribution at different depths in the water phantom under electron beam energy of 6 MeV and 10 MeV.The experimental measurement of transverse dose distribution was carried out.Comparative study and analysis of experimental data and simulation results were carried out.The following results and conclusions were obtained: The maximum dose depth for 6MeV electron beam energy was approximately 1.5cm,and the maximum dose depth at 10 MeV was approximately 2.2cm.The relative deviation between thesimulated data and the experimental results is not more than 5%,which verifies the reliability of the Geant4 simulation method;the uniformity and symmetry analysis of the transverse dose distribution under the electron beam energy of 10 MeV and 10 cm×10 cm is performed,and the results show the transverse dose.The distribution of symmetry and flatness are less than 3%,and have a good orthogonality symmetry,to meet the basic requirements of radiation therapy clinical dosimetry is not greater than3%.