Patent ID: 7260182

Claim:
An x-ray filter assembly comprising: a moveable first filter having a curved portion and a moveable second filter having a curved portion, the moveable first filter and the moveable second filter arranged to move with respect to one another so as to allow formation of a gap therebetween, and wherein the moveable first filter and the moveable second filter mirror one another relative to a central axis of x-ray projection from an x-ray source toward a subject; a third filter having a length perpendicular to the central axis of x-ray projection from the x-ray source toward the subject, the length being longer than at least one of the moveable first and the moveable second filters perpendicular to the central axis of x-ray projection and the third filter being positioned more proximate to the subject than either one of the moveable first filter or the moveable second filter, and positioned to allow attenuation of x-rays that pass through the gap between the moveable first filter and the moveable second filter; a first motor assembly connected to the moveable first filter and a second motor assembly connected to the moveable second filter; and wherein the first and the second motor assemblies are configured to independently position a respective filter in an x-ray path to define an attenuation profile that substantially approximates a target shape.