Investigation Of Dose Planning Technologies For Cervical Cancer Afterloader Brachytherapy

This paper takes the key technology of dose planning in cervical cancer afterload brachytherapy as the research object,and aims to develop a treatment planning system for cervical cancer afterload brachytherapy.This system needs to realize the import and registration of applicator model,the accurate calculation of radioactive dose field,both forward and inverse dose optimization,and the dose planning designation based on 3D individual applicator.Besides,it also needs cervical cancer cases to test its accuracy and reliability.The main research contents and achievements are as follows:Firstly,a treatment planning system for cervical cancer afterload brachytherapy was developed.The functions of this system are included: patient information management,organ segmentation and reconstruction,applicator model import and registration,spatial dose filed calculation and visualization.It also integrates various dose optimization methods,and can make accurate evaluation of treatment plan,assist doctors to complete operation.Secondly,the inverse dose optimization algorithm based on equivalent uniform dose(EUD)was developed.The pure EUD objective and hybrid EUD objective were constructed and optimized by simulated annealing algorithm,which solves the problem that traditional algorithms can’t reflect the biological reaction of dose effect on different organs,it can also reflect the inhomogeneous dose on treatment outcome.According to the cases study,the EUD-based algorithm can significantly improve normal tissues sparing without compromising dose homogeneity and conformity.Finally,the dose planning method based on 3D individual applicator was developed.The individual applicator combined intracavitary applicator and interstitial needles was designed,the dose planning module based on personalized applicator was also integrated into the system.The 3D individual applicator module can solve the problem that the image guidance of interstitial needles,which can standardize treatment process.The experimental results show that this treatment mode can effectively improve the dose distribution results and provide a more reasonable treatment plan.Through the research of dose planning technology in cervical cancer afterload brachytherapy,this paper develops a treatment planning system for cervical cancer afterload brachytherapy,which integrates the EUD-based inverse dose optimization algorithm and the dose planning method based on 3D individual applicator.According to the cases experiment,this system shows a better adaptability,accuracy and operability in making treatment plan.