Absorption Edge Fluoroscopy

The technique presented is an approach to absorp tion edge transmission imaging which eliminates the need for monoenergetic x-ray sources, detector scanning, and energy analysis of transmitted x-rays. Subtraction of images formed with heavily filtered x-ray beams peaked at energies above and below the K absorption edge is accomplished with image-intensified fluoroscopy equipment coupled to a pair of storage tubes. Images of iodine and xenon concentrations of 1 mg/cm2 have been imaged in 15 cm phantoms in a few seconds. When automated, the system will provide similar sensitivity in 20 cm phantoms, with imaging times of 1 second or less with resolution on the order of 1 mm. Several preliminary images are presented which relate to possible future clinical studies.