ELEMENTAL BIOLOGICAL IMAGING BY DIFFERENTIAL ABSORPTION WITH A LASER-PRODUCED X-RAY SOURCE

We demonstrate the novel application of hard x rays emitted by a laser -produced plasma for differential imaging of elements. An x-ray-emitti ng laser-produced plasma, obtained by the focusing of radiation from a 10-Hz terawatt laser, is used for biological imaging. The x-ray sourc e can be arranged to yield characteristic x-ray emission lines with ph oton energies that bridge the K absorption edge of a chosen atomic spe cies. One can obtain element-specific radiographs by recording transil lumination images for different target materials on digital image plat es and by subsequently subtracting or dividing the images. Successful phantom and experimental animal imaging are performed utilizing tantal um and gadolinium as target materials for the terawatt laser and gadol inium as the imaged contrast agent. (C) 1996 Optical Society of Americ a