Multi-plate volumetric CT scanner gap compensation method and apparatus

A CT detector apparatus for use with a radiation source that generates a radiation fan beam having a width and a thickness, the apparatus for collecting beam ray intensity signals and comprising:

• at least first and second digital detector panels, each detector panel having a panel width and a panel length, the panels juxtaposed in a side-by-side arrangement to form a panel array wherein each panel length extends essentially across the entire detection area thickness and the combined panel widths extend essentially across the entire detection area width;
• wherein the fan beam includes a central ray and a plurality of lateral rays defining fan angles on both sides of the central ray, the central ray defining a fan beam projection angle and wherein during acquisition each of the source and array are rotated about an imaging area to collect signals from a plurality of projection angles, each projection angle and fan angle defining a ray trajectory through the imaging area, during acquisition a conjugate pair including first and second oppositely directed rays are directed along each trajectory, the first and second panels forming a gap there between, a transition region including at least the area of the gap, at least some rays directed toward the transition region, the panels arranged such that, for each conjugate pair, if the first ray is directed toward the transition region, the second ray subtends a non-transition region panel section and the resulting signals for the trajectory comprise an incomplete conjugate signal pair.

A method for use with a system including a radiation source and a detector array, the array including at least first and second digital detector panels, each detector panel having a panel width and a panel length, the panels juxtaposed in a side-by-side arrangement to form a panel array with gaps between each two adjacent panels, the source generating a radiation fan beam having a width and a thickness, each panel length extending essentially across the entire detection area thickness and the combined panel widths extend essentially across the entire detection area width, the beam including a central ray and a plurality of lateral rays defining fan angles on both sides of the central ray, the central ray defining a fan beam projection angle and wherein during data acquisition each of the source and array are rotated about an imaging area to collect ray intensity signals from a plurality of projection angles, each projection angle and fan angle defining a ray trajectory through the imaging area, during data acquisition conjugate ray pairs including first and second oppositely directed rays directed along each ray trajectory, each two adjacent panels forming a gap there between such that during data acquisition no data is collected for ray trajectories between the source and each of the gaps, the method comprising the steps of:

• arranging the panels such that, for each ray trajectory, if the first ray is directed toward a gap, the second ray subtends a panel and the resulting signals for the trajectory comprise an incomplete conjugate signal pair including a collected signal;
• and
• after data acquisition, for each incomplete pair, using the collected signal to generate an estimated signal for the second ray.

A CT system comprising:

• a supporter;
• a radiation source mounted to the supporter for rotation about a rotation axis and an imaging area, the source generating a radiation fan beam having a width and a thickness, the fan beam including a central ray and a plurality of lateral rays defining fan angles on both sides of the central ray, the central ray defining a fan beam projection angle;
• at least first and second detector panels, each detector panel having a panel width and a panel length, the panels juxtaposed in a side-by-side arrangement to form a panel array, the array mounted to the supporter opposite the source for rotation about the axis, each panel length extending essentially across the entire detection area thickness and the combined panel widths extending essentially across the entire detection area width, wherein, during acquisition each of the source and array are rotated about the imaging area to collect signals from a plurality of projection angles, each projection angle and fan angle defining a ray trajectory through the imaging area, during data acquisition conjugate ray pairs including oppositely directed first and second rays directed along each ray trajectory, adjacent panels forming a gap there between such that during acquisition no signal is collected for ray trajectories between the source and each of the gaps, the panels arranged such that, for each ray trajectory, if the first ray subtends a gap the second ray subtends a panel and the resulting signals for the trajectory comprise an incomplete conjugate signal pair, for each incomplete pair the signal corresponding to the ray that subtends a panel being a collected signal;
• and
• a processor that receives the signals and that, for each incomplete pair, generates an estimated signal for the second ray as a function of at least the collected signals.