In this study we present Vista-Mamma 50, a novel detection system for high resolution real-time digital mammography. A matrix sensor (12 cm x 12 cm) consists of a high luminance CsI:Tl crystal grown with columnar structure on the top of a <i>pin</i> photodiode matrix driven by CMOS transistors. This imaging technology is known to allow achievement of a pixel size as small as 50 μm or less with a fill factor of the sensitive area of about 80%. The sensor is equipped with a fast real-time electronic system for readout and digitization of images with a dynamic range of 12 bits. Images can be obtained at a frame rate as high as 9 images per second in a 4 x 4 binning operation mode. Appropriate computerized control tools, real-time image treatment, data representation and off-line analysis have been developed. On-line image processing is automatically applied to each frame, including offset and gain corrections and masking of defective pixels. Quantitative measurements including dose response, modulation transfer function (MTF) and detective quantum efficiency are presented. It was found that the detector response shows linear dependence on the entrance dose. The results from the MTF showed that a resolution of equal to or greater than 8 lp/mm could be achieved. The high value of the DQE obtained could be ascribed to the large fill factor. The high resolution detector that we present is well adapted to the image quality which is required by the standards for applications in mammography. Some preliminary results have been obtained for microcalcifications performed on equivalent breast phantoms. Clinical tests are in progress.
The main goal of this paper is the optimization of X-View, a turn-key detection system for high resolution and real-time X-ray non-destructive testing. X-View consists of an microfocus X-ray generator and an acquisition detection system. Two large area detection systems have been developed based on amorphous (a-Si:H) and new CMOS technologies.
The first one consists of an X-ray scintillator converter, arrays of amorphous silicon thin film transistors (TFT) and photodiodes (pitch down to 100 μm). The second one, based on CMOS technology, used in high resolution applications, consists of a scintillator and arrays of CMOS photodiodes (pitch of 50 μm). Both are equipped with a fast real-time electronic system for readout and digitization of images and appropriate computer tools for control, real-time image treatment data representation and off-line analysis.
Images quality have been improved using a microfocus X-ray generator (focus of 50 μm). Decreasing the spot size of the generator improves the X-ray image quality. The geometric blurring is reduced, and object magnifications are possible.
Our study presents the main characteristics of both detection systems (wide dynamic range, lack of blooming, high frame rate), quantitative and qualitative analysis X-ray inspection applications (electronics, various industries, medical, pharmaceutical, etc).