Analysis Of Factors Affecting Set-up Errors Of Thoracic Cancer Treated With Tomotherapy

Objective:Study the factors affecting set-up errors of thoracic cancer treated with Tomotherapy.Analyze that age?sex?BMI?the tumor's position of the patient whether affect set-up errors during the treatment of Tomotherapy,especially BMI,rarely reported at home and abroad.It is expected that our work can be helpful for the clinical application of planning target volume margins and implement individualized treatment.Then compare the set-up errors on X?Y?Z-axis between Automatic Registration and Manual Registration and judge if Manual Registration is necessary before treatment.Methods:205 patients with thoracic cancer treated with Tomotherapy were collected from the First Affiliated Hospital of Kunming Medical University from May 2011 to Junuary 2018,including 96 patients with tumors located in lung,39 patients with breast cancers composed of 21 patients receiving breast conserving surgery and 18 patients receiving radical mastectomy and 70 patients with tumors located in mediastinum(including esophagus cancer).Then collect the age,sex,height,weight,BMI,the location of tumors and the set-up errors in first two weeks of all patients,2050 groups of datas in total.Subsequently analyze the correlation between those clinical indexes above and set-up errors.Results:1?AutoX?AutoZ?ManuX?ManuZ between different sexes were significantly different(P<0.05),AutoY?ManuY were not significantly different(P>0.05),the set-up errors on X,Y-axis of female were larger than that of male;2?AutoX?AutoY?AutoZ?ManuX?ManuY?ManuZ between two age groups were significantly different(P<0.05),there was a positive correlation between age and AutoY?ManuY(r?0.076.0.079,P<0.05),there was a negative correlation between age and AutoX?AutoZ?ManuX?ManuZ(r?-0.078?-0.123?-0.085?-0.113,P<0.05);3?There was a positive correlation between BMI and AutoX?AutoZ?ManuX?ManuZ(r=0.078?0.067?0.088?0.067,P<0.05),but there was no correlation between BMI and AutoY?ManuY(P>0.05),the set-up errors become larger with increased BMI(except Y-axis in obese patients);4?AutoX?AutoY?AutoZ?ManuX?ManuY?ManuZ between different tumors were significantly different(p<0.05),the set-up errors were largest on Y-axis among patients with thoracic cancers;5.AutoX?ManuX between different surgeries of breast cancer were significantly different(P<0.05),the set-up error on X-axis of patients receiving breast conserving surgery was larger than that receiving radical mastectomy;6?The set-up error on X-axis between Automatic Registration and Manual Registration was significantly different(P=0.008),while that on Y,Z-axis did have no statistical significance(P>0.05).Conclusions:1?Sex?age?BMI?the location of tumors were factors affecting set-up errors of patients with thoracic tumors;2?The set-up errors on X?Z-axis of femal were larger than that of male;3?The set-up errors on X?Z-axis were smaller with increasing age while that on Y-axis was larger;4?PTV on X?Y?Z-axis shoud be increased with increased BMI;5?The set-up errors on Y-axis of thoracic tumors was largest;6?PTV on X?Y?Z-axis were different in different locations of thoracic tumors;7?AutoX?ManuX between different surgeries of breast cancer were significantly different,the set-up error on X-axis of patients receiving breast conserving surgery was larger than that receiving radical mastectomy;8?Manual Registration is necessary for patients with thoracic tumors treated with Helical Tomotherapy to reduce the set-up errors on X-axis.