Study On Technology Of Target Dose Optimization In Tumor Radiotherapy

Cancer is a polygenic and multicellular disease,which can occur in all cell types and organs,and has multifactorial etiology.In recent years’ statistics,the incidence rate and mortality of cancer for both men and women are increasing,and cancer has also caused a huge economic burden,especially in developing countries.The mortality rate of cancer in China is still on the rise,but after the country adjusted the population age structure,the standardized mortality rate began to decline slowly.Cancer is a disease that is difficult to cure,but with the development of science and technology,there are many kinds of treatment methods for cancer,including five treatment methods,surgery,chemotherapy,radiotherapy,endocrine therapy and targeted treatment.Radiotherapy has become more important with the development of technology.The most important thing in radiotherapy is the precise radiotherapy of the target area.The upgrading of the planning system,the upgrading of the treatment machine and the transformation of the auxiliary equipment are all aimed at achieving the precise treatment of more accurate irradiation at the target area.In view of this,this study focuses on the optimization of planning methods,the upgrading of multileaf collimators and the use of compensators,studies the dosimetric differences caused by them,and focuses on the impact of these three methods on the target dose.On the optimization of the planning method,the application of the generalized equivalent uniform dose optimization method is studied.Eight patients with esophageal cancer were selected for physical optimization and generalized equivalent uniform dose optimization.Through understanding the effects of different calculation methods on target areas and organs at risk,their differences were compared in dosimetry.The advantages of the generalized equivalent uniform dose optimization method are obtained.The use of the generalized equivalent uniform dose bio-optimization method to design the plan can better limit the dose of the organ at risk.The dose curve is moved downward to the left while ensuring that the target dose does not change significantly,and the dose of the organ at risk becomes lower while ensuring the target dose,thus protecting the organ at risk.In the upgrade of radiotherapy machine,the original MLCi2 multileaf collimator was upgraded to Agility multileaf collimator,and the dosimetric differences caused by the multileaf collimator before and after the upgrade were studied.30 patients with different tumors were studied,including 3 patients with double target areas.When the collimator is different,each patient will generate two treatment plans to study the differences in the target area dose,the dose endangering organs and the use of isolated island fields.It is concluded that Agility multileaf collimator can generate a large number of isolated island fields.According to statistics,the number of isolated island fields has reached more than half on average.The isolated island fields can greatly improve the carving ability of tumor areas,which not only has advantages for dose carving of double target areas,but also significantly improves the dose carving of complex shape target areas,achieving the effect of improving the conformability of tumors and reducing the dose of organs at risk.In this experiment,the research on the organs endangered by chest and neck tumors showed that the doses of organ lung V20,small intestine Dmax and parotid gland V50 were lower.It can be seen that the Agility multileaf collimator can not only make the tumor area have better uniformity and fitness,but also reduce the dose value of the organs endangered.Research the integration of 3D printing technology and compensation materials in the application of compensation materials.19 cases of breast cancer patients were selected to extract,make and apply the compensations,so as to make personalized 3D printing compensations more suitable for human body.Study the differences in target dose,organ threatening dose,and cavity of 3D printing compensators,and compare them clinically.Verify the superiority of 3D printing compensation materials.In the radiotherapy of breast cancer,3D printing compensation is better than conventional compensation,and it is better than conventional compensation in the generation of cavity volume,the application of dosimetry,the protection of endangered organs,and the fitness with human body.Under the same radiation conditions and radiation fields,3D printing compensation materials can better restore the virtual compensation materials generated by the system to the therapeutic effect.This study indicates that in terms of plan design,the physical optimization method has been updated to the generalized equivalent uniform dose optimization method.Upgrade the MLCi2 collimator to Agility multi leaf collimator for machine use.Change the traditional conventional compensation materials in the use of compensation materials and use 3D printing compensation materials that are more suitable for ergonomics.A comparative study was conducted on the three key technologies of radiation therapy,including plan design,machine use,and compensation material use,to confirm its superiority.It not only improves the uniformity and conformability of target dose,but also better protects endangered organs.