[Irradiation field controls by digital luminescence radiography]

Since portal images taken with conventional X-ray films suffer from poor contrast and unsharpness due to the high energy of the radiation beam, scattered radiation, patient motion, and the large dimensions of the radiation source, comparison of portal images with simulation images is often difficult and time consuming. Therefore many efforts have been made to improve such images. The use of storage phosphors and electronic image post-processing provides a remarkable improvement of image quality with better delineation of anatomical landmarks in high contrast areas such as head, neck, and mediastinum, as well as in low contrast regions, i.e. abdomen and pelvis.