Patent ID: 6850588
Filing Date: 2005-02-01
Classification: A61B

Abstract:
1. A method for reducing radiation exposure from an imaging system adapted to provide a radiation distribution about an object cavity during a scan, the imaging system including an object cavity and a radiation source having a gantry angular position wherein the radiation source is rotatably associated with the imagine system so as to rotate around the object cavity, the method comprising: determining an entry location representative of a location of a hand, the entry location having an entry angular range; operating the imaging system so as to cause the imaging system to emit radiation having a radiation intensity and an angular radiation distribution comprising a first angular radiation distribution suitable for a 360 degree image reconstruction or a second angular radiation distribution suitable for a 180 degree image reconstruction, said first angular radiation distribution having a first average radiation distribution, said second angular radiation distribution having a second average radiation distribution, said first or second angular radiation distributions varying in intensity throughout the scan, and said first or second average radiation distributions being about constant throughout said scan; controlling said radiation intensity in a manner responsive to said entry location so as to create image data; and processing said image data so as to create processed image data; wherein said controlling comprises: in response to said first radiation distribution, controlling said radiation intensity such that said radiation intensity is decreased relative to said first average radiation distribution by a predetermined minimization amount when said gantry angular position is within said entry angular range, and controlling said radiation intensity such that said radiation intensity is increased relative to said first average radiation distribution by the predetermined minimization amount when said gantry angular position is at about 180 degrees relative to said entry angular range; and in response to said second radiation distribution, controlling said radiation intensity such that said radiation intensity is decreased relative to said second average radiation distribution by a predetermined minimization amount when said gantry angular position is within said entry angular range, and controlling said radiation intensity such that said radiation intensity is increased relative to said second average radiation distribution by the predetermined minimization amount when said gantry angular position is at about 90 degrees relative to said entry angular range.