| Research backgroundLung cancer ranks first in the incidence and mortality rate of all cancers,Most patients have lost the opportunity to operate in the discovery of lung cancer.Up to 50% of the patients with lung cancer should be treated with radiotherapy to control the disease and improve the quality of life.The most widely used technique of intensity modulated radiation therapy and spiral fault radiotherapy is becoming more and more important in the treatment of lung cancer,Although spiral fault radiotherapy is used in the treatment of solid tumors other than lung cancer,More and more studies have suggested that it has an absolute advantage over the dose distribution and conformability of the general intensity modulated radiation therapy in the target area.It also showed excellent local control of the disease.Before the application of the second generation spiral fault radiotherapy system(Helical tomotherapy),Many studies on the treatment of lung cancer with spiral computed tomography and general intensity modulated radiation therapy,Although pointed out that it has achieved good dose distribution and target conformability,But due to the application of the first generation spiral fault radiotherapy system(Helical tomotherapy),The volume percentage of low-dose lung area(V5)was higher than that of normal intensity modulated radiation therapy(RT).The incidence of radionuclide pneumonia in patients was increased.Most of the results suggest that the use of spiral fault radiation therapy system(the first generation of Helical tomotherapy)is not recommended for the treatment of lung cancer.However,more and more studies on solid tumors of the new generation of helical tomographic radiotherapy system(the second generation of Helical tomotherapy)suggest that they are better than the conventional intensity modulated radiation therapy.But what is the effect and side effects of lung cancer? Further analysis and comparison are needed to provide a basis for clinical decision making.ObjectiveComparison and analysis of differences in dosimetry and clinical efficacy when second generations of Helical TOMOtherapy and IMRT were used for the treatment of lung cancer.Provide a clinical decision for radiotherapy of lung cancer.Methods and materialsThe patients with non-small cell lung cancer or small cell lung cancer(stage II-III)diagnosed by pathology in the First Affiliated Hospital of Zhengzhou University from December 2015 to March-2017 were analyzed.A total of 49 patients were eligible for the study.All of these patients were carried out the radiotherapy plan and radiotherapy plan based on the unified standard(domestic expert consensus and recommended target area delineation and planning verification standards).And the quality control of the treatment plan is strictly carried out.All patients were treated in accordance with the planned plan.Of the 23 patients in the TOMO treatment group and 26 patients in the IMRT treatment group,Finally,the parameters related to radiotherapy(such as lung V5,V10,V20,V30,target area conformability parameter,target area evenness parameter)were collected through radiation plan and treatment system.The follow-up data of clinical efficacy and adverse reactions were collected by telephone and hospital information system.The data of the radiotherapy related parameters,the clinical efficacy and the incidence of adverse reactions in the Tomotherapy treatment group and the IMRT treatment group were statistically analyzed by SPSS20.0 statistical software.Statistical analysis using t test or non parametric rank sum test of two sample mean numbers,There are statistical differences when P<0.05.The difference of dose uniformity and target conformability between the two groups is analyzed by statistical analysis.The difference between the local control of the disease and the incidence of radiation pneumonia in the two groups of patients after treatment is analyzed.The advantages of general intensity modulated radiation therapy(RT)and spiral fault radiotherapy(cum second generation Helical tomotherapy)for the treatment of lung cancer were compared.Result1.The PGTV volume distribution in the target area of the patients in the TOMO treatment group and the IMRT treatment group were as follows: 123.97±60.71 and 168.06±208.37,P=0.749;The volume of lung in the TOMO treatment group and the IMRT treatment group were 2660.91±918.93 and 2778.77±749.84,P=0.548;The ratio of PGTV to total lung volume in group TOMO and IMRT was 0.0499±0.2589 and 0.0590±0.06392,P=0.873.2.The mean dose uniformity index of PGTV dose in target area of TOMO treatment group and IMRT treatment group was 1.07±0.03 and 1.07±0.02,P=0.943.The dose conformability index of PGTV in target area of group TOMO and group IMRT were 0.74±0.21 and 0.54±0.27,P=0.005.The average percentage of total lung V5 in group TOMO and IMRT group were 49.74±9.13 and 53.97±9.92,P=0.129.The average percentage of total lung V20 in group TOMO and IMRT group was 20.44±5.92 and 25.03±5.60,P=0.008.The average total lung dose of Dmean in group TOMO and group IMRT were 12.67±2.68 and 14.21±2.77,P=0.016.3.The average V5 of the affected side lung of the TOMO treatment group and the IMRT treatment group were 65.46±12.78 and 69.00±13.30,P=0.385;The mean value of V20 in the affected side lung of group TOMO and IMRT group were 36.53±7.31 and 43.68±9.30,P=0.008;The V50 of the esophagus in group TOMO and group IMRT were 15.21±16.39 and 20.16±15.01,P=0.335;The mean average Dmean of the esophagus in group TOMO and IMRT group was 18.28±9.16 and 23.22±7.35,P=0.074;The mean cardiac V30 in group TOMO and group IMRT were 19.32±12.64 and 13.22±11.42,P=0.082;The cardiac average dose of Deman in group TOMO and group IMRT was 15.08±7.48 and 11.01±7.41,P=0.062;The mean Max of spinal cord in group TOMO and group IMRT were 35.60±9.34 and 36.62±2.96,P=0.600;The mean average Dmean of the spinal cord in the TOMO and IMRT groups was 10.65±4.57 and 9.52±3.57,P=0.337.4.The local control of disease between group TOMO and group IMRT was as follows :23 patients in group TOMO,of which 21 were effective,2 were ineffective,and the effective rate was 91.30%;Group IMRT total of 26 patients,of which 22 of the effective,4 ineffective,effective rate was 84.61%;after the chi square test(P=0.782).5.The incidence of TOMO group and IMRT group is more than grade 3 radiation pneumonitis: group TOMO,a total of 23 people,more than 3 cases of pneumonia occurred in 3,the incidence rate was 13.04%;The total number of group IMRT was 26,more than grade 3 radiation pneumonia cases was 5,the incidence was 19.23%,but after statistical analysis of the chi square test(P=0.843).Conclusion1.In the use of TOMO and IMRT for the treatment of lung cancer,the conformability of the PGTV target area in group TOMO was better than that of the conventional intensity modulated radiation therapy group(IMRT).There was no difference in the dose uniformity between the TOMO and the IMRT groups in the target area of the PGTV target.2.In the dosimetry analysis of group TOMO and group IMRT,the amount of V20 in the total lung and V20 of the affected side lung was significantly better in the TOMO group than in the IMRT group.The total exposure dose of TOMO group was better than that of the IMRT group.There was no difference between the two groups in the comparison of the total lung V5 and the lung V5 in the affected side.3.There was no difference in esophageal V50,esophageal Deman,heart V30,heart Deman,spinal cord Max and spinal cord Deman between group TOMO and group IMRT in terms of radiation dose.4.when use TOMO or IMRT for the treatment of lung cancer,the local control of disease in the two groups was the same,and the occurrence of radionuclide pneumonia was also the same. |
