Study On Quantitative Evaluation Method Of Radiotherapy Planning Quality

The design of the radiotherapy plan contains two steps:optimization and evaluation.The evaluation of plan is usually based on the experience of the radiologist.The evaluation method is so subjective.This study aims to explore a script evaluation method for quantitative rules that visually reflects the quality level of radiotherapy plans,so as to effectively and objectively evaluate plan quality.Twenty rectal cancer patients at 2017-2018 were selected from Xiangya Hospital,including 10 IMRT plans and 10 VMAT plans.Dosimetric comparisons were made between the two groups,and the dosimetric differences were obtained.Then plans were imported into PlanIQ for evaluation.Based on the RTOG protocol and official guidelines,Plan Quality Metrics?PQM?were established in PlanIQ to quantify each dosimetric indicator to be evaluated.Quantify the score and get the total score of these plans.The scores of targets,scores of OAR?organ at risk?and total scores in the two groups were compared,and the clinical feasibility of the PQM based quantitative evaluation software was verified by comparing the dosimetric parameters of the two groups.Under the premise of verifying the clinical feasibility of the evaluation software,develop an evaluation script with the score function,select the same batch of cases for evaluation and scoring,compare the scores of the two groups of the obtained plans,and then carry out the evaluation script and Plan.The horizontal comparison between the script and Plan IQ is carried out,and the clinical feasibility of the script method of evaluating is verified.By comparing the dosimetry of the two groups:the target D₉₈,V₁₀₇,Dmax;small intestine V_45,D_max;right femoral head V₄₀,D_max;left femoral head V₄₀,V₄₅,Dmax;bladder V₄₀,V₄₅,the differences of the above indicators were statistically significant.Moreover,the VMAT plans are superior to the IMRT plans in target hotspot control and OAR sparing.The total scores of PlanIQ in the two groups were?84.6±5.9,71.8±9.96?,the difference was statistically significant?P=0.003<0.05?;the target scores were?71.7±18.3,64.9±7.5?the difference was statistically significant?P=0.027<0.05?,and OAR scores were?89.8±4.9,74.8±10.8?the difference was statistically significant?P=0.001<0.05?,the results objectively reflect the dosimetric difference between the two irradiation techniques.comparison between the Script method and Plan IQ,the total scores evaluated by the script method were?84.1±8.1,70.2±10.0?,the difference was statistically significant?P=0.003<0.05?;the target score were?73.2±16.6,56.8±14.9?,the difference was statistically significant?P=0.027<0.05?;the OAR scores were?91.9±3.2,80.4±8.5?,the difference was statistically significant?P=0.002<0.05?.The Pearson correlation coefficient between the two methods all exceeded 0.8,showing a strong correlation;Bland-Altman consistency analysis was used in 60 samples,and the results showed that the amount of data outside the consistency interval did not exceed 5%.The Plan Quality Metrics Method?PQM?not only reduces time,but also improves the efficiency of planning,and can effectively and objectively quantify the quality of the plan,and also provides a new idea for the plan evaluation.