Patent ID: 7190763
Filing Date: 2007-03-13
Classification: A61B,G21K,H05G

Abstract:
1. A radiography system including an imaging device for imaging a patient by utilizing X-rays and a detecting unit for detecting an exposure the patient receives during radiography, wherein said detecting unit comprises: a first lookup table in which a plurality of values of a dose rate are recorded in association with a plurality of values of a tube voltage of an X-ray tube; a position detector configured to determine a value of a plurality of positions of a plurality of blades of a collimator that limits a range of X-ray radiation; a second lookup table in which a plurality of values of an area of an X-ray field are recorded in association with a plurality of values including the value indicating the positions of the blades; an operating unit configured to receive a tube current of said X-ray tube and a pre-determined value of the tube voltage; and a calculating device for retrieving one of the values of the dose rate which is associated with the pre-determined value of the tube voltage from said first lookup table, retrieving one of the values of the area of the X-ray field which is associated with a value indicating the positions of the blades included in said collimator from said second lookup table, and calculating a product of the dose rate, the area of the X-ray field, the tube current of said X-ray tube, and an X-irradiation time.