Patent ID: 7636413

Claim:
A CT system comprising: a rotatable gantry having an opening for receiving a subject to be scanned; an HF electromagnetic energy source configured to project a number of HF electromagnetic energy beams toward the subject; a generator configured to energize the HF electromagnetic energy source to at least a first energy state and a second energy state; a hub; and a number of HF electromagnetic energy filters extending outward from the hub and positional between the HF electromagnetic energy source and the subject, the number of HF electromagnetic energy filters including at least a first filter and a second filter, wherein the first filter is positionable between the HF electromagnetic energy source and the subject by rotation of the hub to a first position when the HF electromagnetic energy source is energized to the first energy state, and the second filter is positionable between the HF electromagnetic energy source and the subject by rotation of the hub to another position when the HF electromagnetic energy source is energized to the second energy state; wherein the first energy state is different from the second energy state; wherein only one of the first filter and the second filter is positionable between the HF electromagnetic energy source and the subject when the HF electromagnetic energy source is energized to either one of the first energy state or the second energy state; and wherein an axis of rotation between the first position and the another position is in a direction transverse to the projection of HF electromagnetic energy beams from the HF electromagnetic energy source toward the subject.