Application value of styrofoam combined with head and neck shoulder thermoplastic film in position fixation of nasopharyngeal carcinoma treated with helical tomography intensity modulated radiotherapy

ObjectiveTo investigate the application value of styrofoam combined with head and neck shoulder thermoplastic film in position fixation of nasopharyngeal carcinoma treated with helical tomography intensity modulated radiotherapy.

MethodsTwenty nasopharyngeal carcinoma patients treated with CT radiotherapy were randomly divided into the control group and observation group(10 cases in each group).The control group was fixed with regular headrest combined with head and neck shoulder thermoplstic film, and the observation group was fixed with styrofoam combined with head and neck shoulder thermoplastic film.The image was obtained by MVCT scan before treatment, and registered with the image of simulated CT, the pendulum errors of X(left and right), Y(corner), Z(ventral dorsal) and ROLL(rotation along cross section) axis were recorded and analyzed.

ResultsThe pendulum errors of the direction of X, Y, Z and ROLL axises in the control group were(1.58±1.14)mm, (1.44±1.29)mm, (3.19±1.26)mm and(1.16±1.09)°, respectively.The pendulum errors of the direction of X, Y, Z and ROLL axises were(1.06±0.89)mm, (1.02±0.73)mm, (2.71±1.37) mm and(1.31±1.12)°, respectively.The differences of pendulum errors in X, Y and Z axis directions between the two groups were statistically significant(P < 0.01), and the difference of the pendulum error in ROLL axis direction between the two groups was not statistically significant(P>0.05).The pendulum error in the direction of X, Y and Z axis in the control group and observation group mainly concentrated in 0-6 mm and 0-4 mm, respectively.The cross-sectional rotation error distribution at the interval of 0°~, 1.1°~and 2.1°~in observation group was 134(48.2%), 89(32.0%) and 55(19.8%), respectively.The cross-sectional rotation error distribution at the interval of 0°~, 1.1°~and 2.1°~in control group was 177(59.8%), 60(20.3%), and 59(19.9%), respectively.

ConclusionsIn order to reduce the pendulum error, it is recommended to use styrofoam combined with thermoplastic film for the fixation of nasopharyngeal carcinoma patients.