Perspectives of medical X-ray imaging

While X-ray image intensifiers (XII), storage phosphor screens and film-scr een systems are still the work horses of medical imaging, large flat panel solid state detectors using either scintillators and amorphous silicon phot o diode arrays (FD-Si), or direct X-ray conversion in amorphous selenium ar e reaching maturity. The main advantage with respect to image quality and l ow patient dose of the XII and FD-SI systems is caused by the rise of the D etector Quantum Efficiency originating from the application of thick needle -structured phosphor X-ray absorbers. With the detectors getting closer to an optimal state, further progress in medical X-ray imaging requires an imp rovement of the usable source characteristics. The development of clinical monochromatic X-ray sources of high power would not only allow an improved contrast-to-dose ratio by allowing smaller average photon energies in appli cations but would also lead to new imaging techniques. (C) 2001 Elsevier Sc ience B.V. All rights reserved.