Region of interest fluoroscopy

In some medical imaging applications, it is necessary to visualize only the center of the field of view with optimal quality. For example, often in interventional radiographic procedures only the region directly adjacent to the catheter tip must be well seen. A new imaging approach which reduces the number of photons exposing the patient outside a region of interest (ROI), while allowing the photon fluence to be maintained or increased in the ROI, may make more optimal use of the total integral radiation dose to the patient as well as enable increased contrast and reduced artifacts in the ROI. A demonstration is given with an angiographic phantom, for an ROI which is less than 10% of the total field of view and where the periphery receives 6% of the ROI exposure. Contrast is improved about 30% in the ROI, and yet the images are adequate in the periphery for visualizing high contrast reference features while there is a reduction in total integral patient dose. Details of the technique are discussed along with requirements for clinical implementation.