ABSTRACT
Objective@#To preliminarily investigate the difference of position fixation accuracy between polyurethane styrofoam and vacuum negative pressure pad in intensity-modulated radiation therapy (IMRT) after radical mastectomy for breast cancer.@*Methods@#Forty breast cancer patients, who received breast-conserving surgery followed by hyper-fractionated IMRT of the whole breast (42.56 Gy for 16 times) in our hospital between 2017 and 2018 were recruited and randomly divided into the polyurethane styrofoam group and vacuum negative pressure pad group. Before IMRT treatment, the anterior and lateral films of patients were taken with kilovoltage digital radiographs (KVDRs) by Varian Trilogy machine-borne OBI KV image verification system. The KVDRs images were matched with the DRR images reconstructed by the planned system to obtain the setup errors in the left and right, head and foot, and ventral and back directions between two groups. Each patient was verified for 10 times to obtain 400 sets of data. The independent sample t-test was adopted to analyze the setup errors between two groups. The external expansion value of graded setup errors from clinical target volume (CTV) and planned target volume (PTV) was calculated.@*Results@#The setup errors in the left and right, head and foot, ventral and back directions between the styrofoam fixation and vacuum pad groups were (1.63±1.29) mm and (1.83 ±1.61) mm (P=0.18), (1.46±1.51) mm and (2.26±2.03) mm (P=0.00), and (1.30±1.35) mm and (1.91±1.67) mm (P=0.00), respectively. The external expansion values of setup errors from CTV to PTV were 2.19 mm, 2.51 mm, 1.57 mm and 2.40 mm, 3.97 mm and 2.63 mm, respectively.@*Conclusion@#Both two fixation methods meet the clinical requirements. However, the setup accuracy and reproducibility in the polyurethane styrofoam group are better than those in the vacuum negative pressure pad group.
ABSTRACT
Objective To preliminarily investigate the difference of position fixation accuracy between polyurethane styrofoam and vacuum negative pressure pad in intensity-modulated radiation therapy (IMRT) after radical mastectomy for breast cancer.Methods Forty breast cancer patients,who received breast-conserving surgery followed by hyper-fractionated IMRT of the whole breast (42.56 Gy for 16 times) in our hospital between 2017 and 2018 were recruited and randomly divided into the polyurethane styrofoam group and vacuum negative pressure pad group.Before IMRT treatment,the anterior and lateral films of patients were taken with kilovoltage digital radiographs (KVDRs) by Varian Trilogy machine-borne OBI KV image verification system.The KVDRs images were matched with the DRR images reconstructed by the planned system to obtain the setup errors in the left and right,head and foot,and ventral and back directions between two groups.Each patient was verified for 10 times to obtain 400 sets of data.The independent sample t-test was adopted to analyze the setup errors between two groups.The external expansion value of graded setup errors from clinical target volume (CTV) and planned target volume (PTV) was calculated.Results The setup errors in the left and right,head and foot,ventral and back directions between the styrofoam fixation and vacuum pad groups were (1.63± 1.29) mm and (1.83 ± 1.61) mm (P=0.18),(1.46t1.51) mm and (2.26±2.03) mm (P=0.00),and (1.30±1.35) mm and (1.91±1.67) mm (P=0.00),respectively.The external expansion values of setup errors from CTV to PTV were 2.19 mm,2.51 mm,1.57 mm and 2.40 mm,3.97 mm and 2.63 mm,respectively.Conclusion Both two fixation methods meet the clinical requirements.However,the setup accuracy and reproducibility in the polyurethane styrofoam group are better than those in the vacuum negative pressure pad group.
ABSTRACT
Objective To develop a new type of locating rod with easy installation and high reliability for radiotherapy.Methods The locating rod was composed of a joining beam,two clamping buckles and buckle holders.The joining beam had the length being 530+03 mm.One of the buckles was put at one end of the beam,and the other slided along a stool.An eccentric wheel drove the sliding buckle to determine the space between two buckles,and a returning spring was involved in to enhance the compliance of the sliding buckle.Results The rod gained easy installation and operation,and was compatible with the bed board with the width of 5300 mm.There was no sideslip occurred after locking the rod,and the sideslip shift was not more than 1 mm in case of 20 kgf (1 kgf=9.8 N) lateral traction.Conclnsion The rod has high performances and meets clinical requirements.