Comparative Analysis Of The Setup Errors Of Ultrasound Images And CBCT Images In The Radiotherapy Of Cervical Cancer

Objective: To verify the practicability and feasibility of ultrasound guided radiotherapy for cervical cancer by analyzing the positioning errors of the ultrasonography and CBCT images to guide the placement error in cervical cancer radiotherapy.Methods: A total of 10 cases of cervical cancer patients were selected,the implementation of images guided radiotherapy(IGRT),respectively,simulation and enhanced scan,and the radiotherapy was performed by the same radiotherapy physician in the enhancement of CT images.The dose of PTV was 50.4 Gy /28 f,1.8Gy / f.10 patients underwent ultrasonography and CBCT image guidance respectively before radiotherapy,and the three-dimensional direction(Front and rear,left and right and head and foot direction)on the shift.The difference of the three-dimensional direction error between the two methods was obtained and the statistical difference between the two groups was calculated.The dose index of the target area and the organ was endangered,the distribution of the organ dose was collected and the relevant data were collected for statistical analysis.Results: 1.In the left-to-right direction,ultrasound and CBCT verification after shift error values were(2.49 ± 3.65)mm,(2.55 ± 3.09)mm,compare the two methods of position error comparison,no statistically significant difference(P=0.84,t=-2.10);And the fore-and-after direction,ultrasound and CBCT verification after shift error respectively(2.86 ± 4.30)mm,(2.68 ± 3.80)mm,to compare the two methods,the difference was not statistically significant(P=0.34,t=1.03);In the head-foot direction,ultrasound and CBCT verification after shift error values were(3.05 ± 4.47),(3.57 ± 4.61)mm,to compare the two methods,the difference was not statistically significant(P=0.16,t=-1.60)2.The system error of the ultrasound image guidance system in the direction of left-right and head-foot is lower than that of the CBCT system,and the ultrasound image guidance is larger than that of the CBCT in the fore-after direction.3.Each target program can meet the dosimetry requirements,the plan of organs at risk did not exceed the tolerable dose of normal tissues and organs.Conclusions: 1.CBCT image guided radiotherapy for cervical cancer position error is widely used in clinical,ultrasound image guidance and CBCT image guided radiotherapy of cervical cancer setup error comparison,no statistically significant difference,and its operation is simple,no ionizing radiation,small system error,real-time correction,can also be used in clinic.2.The plan in the protection of rectum and bladder and femoral head,all organs are to meet the requirements.IGRT has an advantage in the dose distribution of organs,which can protect the normal tissues and organs around the target area of cervical cancer patients.