Improvement And Code Testing Of Radiotherapy CCK Photon Dose Algorithms

Radiotherapy is one of the main methods of tumor treatment.The application of the treatment planning system is the core part of the radiotherapy process.Dose calculation is the most important part of the treatment planning system,of which the accuracy directly affects the curative effect and health of the patient.The research purpose of our paper is to develop a set of photon dose calculation program with advantages of accuracy and speed,and to verify the feasibility for clinical treatment by the treatment planning system DeepPlan.For the research purpose,two main tasks are performed:(1)Development and accuracy verification of photon dose calculation program based on improved CCK algorithm.First,we use C++programming language to program GPU-accelerated fast ray-tracing algorithm to caculate the total energy release per unit mass in the computer phantom.Then we obtain the kernel of the incident ray in the phantom using Monte Carlo calculation software EGSnrc.Then we program the calculation of the dose distribution in the whole space using convolution and superposition method.Then we accelerate the dose calculation process using the calculation mask,adaptive dose interpolation and other methods.Finally,we verify the accuracy of the photon dose calculation program according to the tests in the YY 0775 national standard report.(2)Verification of the accuracy of the dose calculation by DeepPlan.First,we integrate the photon dose calculation program into DeepPlan.Then we verify the accuracy of the clinical phantom calculation according to the plan tests in the YY/T 0889 national standard report.The clinical patients tests considers 9 patients with tumors near the prostate,15 patients with tumors near the chest and 5 patients with tumors near the head and neck.We inport treatment plans from Pinnacle into DeepPlan for dose re-calculation to compare doses of targets and organs of risk.The organ doses of interest were compared using the Gamma analys in the PTW VeriSoft software.We have achieved corresponding results.First,we developed a photon dose calculation program based on the improved CCK algorithm successfully.And we integrated a variety of acceleration methods into the dose calculation program.The acceleration effect of the water phantom is more than 8.7 times.It was verified that all test examples in the YY 0775 reports have passed.The errors of all test examples in the 0775 report are within 2%.Secondly,it was verified that all test examples in the YY/T 0889 reports have passed.The Gamma pass rates of all the tests in the YY/T 0889 report are above 96.8%.In prostate tumor cases,the 3D Gamma pass rate is(96.9±0.8)%.The 3D Gamma pass rate at the middle layer in chest tumor cases is(98.3±1.3)%.The 3D Gamma pass rate at the middle layer in head-neck tumor cases is(98.8 ± 0.8)%.By report tests and clinical cases tests,the accuracy and the clinical application feasibility of the photon dose calculation program based on the improved CCK algorithm are verified.The results show the sufficient clinical accuracy and advantages of faster calculation speed of the photon dose algorithm based on the improved CCK algorithm.Compared with the conventional analytical algorithm and the Monte Carlo algorithm,the improved CCK algorithm is more suitable for the dose calculation of the treatment planning system.