SEGMENTED CHAMFER MATCHING FOR THE REGISTRATION OF FIELD BORDERS IN RADIOTHERAPY IMAGES

Optimum conformity between treated and prescribed radiotherapy fields is likely to be achieved when the full versatility of modem therapy eq uipment is reflected in the field registration method. To allow for in dependent jaws and custom shielding, chamfer matching has been used to register selected segments of field borders independently. In a study involving 50 clinical prescription-treatment held pairs it is shown t hat segmented chamfer matching is superior not only to conventional un segmented chamfer matching but also to several other methods. An examp le of the clinical value of segmented chamfer matching applied to elec tronic portal images is given.