Abstract

Info

Title:: Comparison of setup accuracy between two immobilization techniques in stereotactic body radiotherapy for head cancer

Author(s):: WANG Meijiao; ZHOU Shun; YUE Haizhen; YU Songmao; WU Hao; WANG Haiyang; ZHANG Yibao; Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing)/Department of Radiotherapy, Peking University Cancer Hospital & Institute, Beijing 100142, China

Keywords:: Keywords: stereotactic body radiotherapy; setup error; single shell positioning system; double shell positioning

Abstract:: Abstract: Objective To compare the differences of setup accuracy in stereotactic body radiotherapy for head cancer using two different immobilization techniques, namely single shell positioning system (SSPS) and double shell positioning system (DSPS). Methods Forty patients treated with stereotactic body radiotherapy for head cancer were diveided into two groups and then immobilized with SSPS (control group) and DSPS (experimental group). After that the pre-treatment cone beam CT images were obtained, the setup errors were acquired through image registration based on bony landmarks for statistical analysis. Results The setup errors (Mean±SD) in lateral (Lat), longitudinal (Lng), vertical (Vrt), Pitch, Roll and rotation (Rtn) directions in control group were (0.26±0.15) cm, (0.13±0.10) cm, (0.19±0.13) cm, (1.40±0.75)°, (1.31±0.65)° and (1.00±0.60)°, respectively, and those in experimental group were (0.07±0.08) cm, (0.14±0.13) cm, (0.09±0.09) cm, (0.73±0.62)°, (0.72±0.58)° and (0.66±0.52)°, respectively. The results of Mann-Whitney U test showed that there were statistical differences between two gourps in Lat, Vrt, Pitch, Roll and Rtn directions (P<0.05), but not in Lng direction (P>0.05). Conclusion Compared with SSPS, DSPS reduces the setup errors in stereotactic body radiotherapy for head caner and improves treatment accuracy, thereby bringing benefits to patients.