Design considerations for direct and indirect active matrix flat-panel portal imagers

Abstract

Background. Recent advances in thin film transistor (TFT) technology have allowed the construction of active matrix flat-panel imagers (AMFPI) for various medical imaging modalities. Since the design of such systems is still in the development stage, it is unclear what detector characteristics are required in order to optimize these detectors for portal imaging.

Material and methods. In this work, we used cascade analysis and Monte Carlo techniques to calculate the DQE for both direct and indirect AMFPIs for portal imaging, and use these calculations to study the optimal detector characteristics. We validate our calculations with existing experimental data.

Results. We show that the for ideal flat-panel characteristics the direct and indirect detection methods have the same DQE for a given mass thickness.

Conclusions. We generate graphs which may be helpful in the design of future megavoltage AMFPIs.