ABSTRACT
Objective To investigate the repeatability of precise radiotherapy placement of self-made adjustable angle wedge plate,negative pressure vacuum pad and conmon soft pillow,corresponding to 3 groups.The study is demonstrated with a thermoplastic membrane immobilization technology in kyphotic deformity patients with head and neck cancer (including primary and secondary),respectively.Methods From Jun 2014 to Apr 2016,48 cases of severe head and neck cancer patients received radiotherapy humpback who were randomly divided into 3 groups.Combined with thermoplastic head and neck shoulder film position fixation,the right foot direction at the end of the skull styloid process layer center was set as a reference point.On the left foot at the end of the direction of styloid process layer center,localization of the origin of the coordinate system in patients around the head and foot,dorsoventrally (x,y,z) analysis of the direction change of position measurement was performed.Results There was no significant difference between the adjustable angle wedge plate and negative pressure vacuum pad groups of the coordinate system (P ＞ 0.05).Compared with common soft pillow group,three dimensional positioning errors and three dimensional coordinate system transfer errors of the adjustable angle wedge plate and negative pressure vacuum pad groups were statistically significantly different (t =-6.99 to-2.69,-5.13 to-2.71,P＜0.05).Conclusions The self-made adjustable angle wedge plate has good repeatability,saves time and money,is simple and durable on precise radiotherapy positioning of kyphotic deformity patients with head and neck cancer.
ABSTRACT
Objective To compare the repeatability of radiotherapy placement between negative pressure vacuum pad (A group) and common soft pillow (B group) combined with a thermoplastic membrane immobilization technology in severe kyphosis patients with head and neck cancer.Methods From September 2013 to December 2014,22 cases of severe kyphosis patients with primary or secondary head and neck cancer who received radiotherapy were randomly divided into group A and group B.Padding waist hips with negative pressure vacuum pad and ordinary soft pillow were used so that the patients could lay in CT-Sim bed,and the head cushion was set on the headrest.After the fixing of thermoplastic head and neck shoulder membrane,CT-Sim was located.Every five times of radiotherapy were accompanied by CT-Sim school position once.In the direction of the last layer of right styloid process center point as the reference point,CT-sim software was used to measure the location change with left and right sides,head,and under direction (x,y,z,respectively) in patients,and the data were analyzed.Results Group A significantly reduced the osseous placement error between tags compared with group B (P ＜ 0.05).The average placement errors were as follows,x:(0.68±0.14) mm vs (1.15±0.77) mm,y:(0.48±0.23) mm vs (1.49±1.24) mm,z:(0.76±0.54) mm vs (2.11±1.02) mm,while the average transfer errors were as follows,x:(0.70±0.21) mm vs (1.15±0.93) mm,y:(0.50±0.31) mm vs (1.50±1.28) mm,z:(0.85±0.26) mm vs (1.77±0.88) mm.Conclusion Vacuum suction pad combined with thermoplastic membrane has good repeatability on radiotherapy positioning for severe kyphosis patients with head and neck cancer.