| With the improvement of living standards and environmental impact,cancer has become one of the most important diseases that threaten people’s health.Radiation therapy,as one of the key method of tumor treatment,has an irreplaceable position in the treatment of tumors.At present,only physical dose calculations other than equivalent biological dose calculations are available during radiotherapy,and tissue bioreaction cannot be accurately assessed.How to combine computer technology and radiotherapy technology to achieve computer aided decision(CAD)and precision medical treatment is one of the important research fields of computer technology.In this paper,the linear quadratic(LQ)model is studied and improved,and the improved one is applied to the latest radiotherapy body radiotherapy(SBRT)for equivalent biological dose calculation.Then the improved model is used as the core algorithm to develop the equivalent biological dose calculation CAD system,which assists the oncologist to accurately evaluate the biological response of the tissue during the radiotherapy process,so as to strive to achieve accurate treatment of the tumor.The use of computer technology to achieve equivalent biological dose calculation in SBRT is an important research field of CAD and an indispensable tool in radiotherapy.The main work of this paper is from the following aspects:(1)A linear quadratic repair model was proposed for the defect of underestimation of cell survival in the high-dose region of the LQ model in SBRT.In this paper,the linear quadratic repair model is obtained by adding the correction function with curvature constraint ability,and then the repair model is deduced to obtain the equivalent biological dose model based on the repair model.The experimental results show that the linear quadratic correction model has better fitting accuracy than the LQ model(average χ2/df: 0.4739 vs.2.9161).(2)For cell sensitivity,this paper proposes a linear quadratic improvement model and a cellular hypersensitivity model.The linear quadratic improvement model improves the LQ model by adding the curvature constraint correction factor with adaptive ability.The experimental results show that the linear quadratic improvement model has stronger adaptability to different cell lines than the linear quadratic repair model.Further,this paper also conducted an exploratory study on the ultra-low dose hypersensitivity reaction of cells,and constructed a cell hypersensitivity model to describe the biological response of cells under very low dose conditions.(3)According to the proposed equivalent biological dose calculation model obtained by the linear quadratic improvement model,this paper designs and implements the equivalent biological dose calculation and evaluation system.Firstly,the quantity matrix in the.dicom file in the radiotherapy plan is extracted into the.mat format,and the visualization of the radiotherapy dosimeter structure file is realized.Then the plan file is parsed to obtain the structure matrix and the dose matrix,and the linear quadratic improvement model proposed in this paper is made.The application of the core algorithm to the system improves the accuracy of the biological dose calculation in the CAD system.Finally,based on the LQ model,the linear quadratic repair model and the linear quadratic improvement model,the radiotherapy dose conversion function is realized.In this paper,by improving the LQ model,an improved BED model is obtained,which overcomes the shortcomings of the traditional BED model in overestimating the biological dose in SBRT.The improved BED model was then applied to the equivalent biological dose of SBRT and an equivalent biological dose CAD system was developed.The system realizes the calculation and visualization of biological dose,quantitatively evaluates the biological effects of tissue during radiotherapy,provides a good human-computer interaction interface and accurate biological dose calculation service for medical staff,and has practical application value. |
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