Active Scanning System Research Articles

Digital detectors for mammography: the technical challenges

This paper reviews the different techniques available and competing for full-field digital mammography. The detectors are described in their principles: photostimulable storage phosphor plates inserted as a cassette in a conventional mammography unit, dedicated active matrix detectors (i.e., flat-panel, thin-film transistor-based detectors) and scanning systems, using indirect and direct X-ray conversion. The main parameters that characterize the performances of the current systems and influence the quality of digital images are briefly explained: spatial resolution, detective quantum efficiency and modulation transfer function. Overall performances are often the result of compromises in the choice of technology.

Dye laser wavelength stabilization: An active control by interferometric fringe detection

An active wavelength stabilization and scanning system is described which reduces the dye laser wavelength fluctuation under feedback by detecting the changes in the fringe diameter of a temperature-stabilized Fabry–Perot interferometer with the help of two photodiodes. An estimate of the wavelength drift due to thermal effects is made. Short- and long-term fluctuations in the wavelength, monitored by recording iodine fluorescence are reported. The system response to a sudden external disturbance to the wavelength was studied.