A typical X-ray imaging system comprises an X-ray source and an X-ray detector. The X-rays that are emitted from the X-ray source can impinge on the X-ray detector and provide an X-ray image of the object (or objects) that are placed between the X-ray source and the X-ray detector. In one type of X-ray imaging system, a fluoroscopic imaging system, the X-ray detector is often an image intensifier or, more recently, a flat panel digital detector.
In many medical imaging applications, a collimator is placed between the X-ray source and the X-ray detector to limit the size and shape of the field of the X-ray beam. The collimator can shape or limit the X-ray beam to an area of a patient's body that requires imaging. Accordingly, the collimator can prevent unnecessary X-ray exposure to areas surrounding the body part that is being imaged. By reducing the amount of X-ray exposure around the body part being imaged, the collimator may protect the patient from needless X-ray exposure. And because the collimator can limit the X-rays that hit the X-ray detector around the body part that is being imaged, the collimator can also help to improve image contrast and quality. For instance, by preventing excess X-rays from impinging on a flat panel digital detector, the collimator can help reduce or prevent image blooming or bleeding, which tends to occur when the detector is overloaded with X-rays. Thus, the collimator can minimize X-ray exposure and maximize the efficiency of the X-ray dosage to obtain an optimum amount of data for diagnosis.