Accuracy study of different registration methods for cone beam CT and planning CT in image-guided radiation therapy / 中华放射肿瘤学杂志

ABSTRACT

Objective To evaluate the accuracy of image registration based on bony structure (RBS) and grey-scale (RGS) in positioning correction of radiation treatment,and their reliability in clinical application.Methods Setup errors of anthropomorphic phantom (chest& abdomen,head& neck) were simulated with x-,y-,z-directions.CBCT images were acquired for each simulation and registered with planning CT.using bony structure and grey-scale registration separately.Geometry accuracy of all registration were then obtained and analyzed.Results The errors of RBS and RGS in x-,y-,z-directions were (-0.65 ±0.22) mm and (-0.70±0.17) mm (P=0.00),(1.02 ±0.27) mm and (0.90±0.20) mm (P =0.00),(1.46 ± 0.53) mm and (1.47 ± 0.47) mm (P =0.54) for head& neck positioning; with (0.82±0.33) mm and (0.79±0.18) mm (P=0.03),(2.45±1.17) mm and (1.61 ±0.84) mm (P =0.00),(1.44 ± 3.25) mm and (0.19 ± 1.11) mm (P =0.00) for chest& abdomen positioning.Conclusions RGS is more accurate and stable than RBS.The accuracy of image registration is a little better for head& neck than that for chest& abdomen.The algorithms of image registration used in clinical application needs to be tested independently and the systematic error needs to be corrected before applying in different treatment techniques according to their accuracy requirement.