Collimation device and method for acquiring a radiation image of a long body part using direct digital X-ray detectors

A method for acquiring a radiographic image of an elongated body part, comprising:

• positioning an elongated human body part between a source of x-rays and a digital image capture device having an imaging dimension which is less than a like dimension of said elongated body part;
• wherein said image source is stationary and said source projects an x-ray pattern which encompasses said elongated body part;
• moving said digital image capture device in a direction parallel to said known imaging dimension to sequential contiguous stationary positions to acquire a sequence of radiographic images of said elongated body part;
• and
• moving an assembly of x-ray opaque material which is positioned between said source of x-rays and said elongated body part, and which has an opening for allowing passage of x-rays, such that said opening is synchronized with the movement of said digital image capture device to facilitate acquisition of said sequence of radiographic images at said stationary positions.

In a radiographic imaging system including a source of x-rays and an adjustable collimator associated with said source of x-rays for limiting the size of the x-ray beam projected to an object to be x-rayed, a shutter comprising;

• a blade of x-ray opaque material having a plurality of fixed openings which are arrayed circumferentially, said blade being positioned contiguous to said collimator;
• and
• a blade drive for moving said blade in a rotational direction to position said circumferential, said blade being positioned contiguous to said collimator;
• and
• a blade drive for moving said blade in a rotational direction to position said circumferential array of openings in sequential, contiguous, stationary positions to control exposure of said object along a vertical direction.