System design of a low-cost digital x-ray detector

Abstract

Despite the LCD monitor manufacturing costs per square inch dropping below $2 this year, full-size, 14″×17″ digital chest x-ray detector systems are still being sold commercially for tens of thousands of dollars, for two main reasons. First, the extra required p+ doped silicon layer cannot be deposited in the same fabrication facility as a standard thin-film transistor panel for LCD monitors. Secondly, low volume of sales of digital radiography panels result in large margins and high sales prices for detector manufacturers. In this report, we show the system design of a truly low-cost, digital x-ray detector. The primary cost-cutting technique is the replacement of conventional, vertical PIN photodetectors with lateral metal-semiconductor-metal photodetectors, which can be fabricated using existing TFT processes. This paper covers the design of the pixel architecture, pixel array, and readout electronics.