In indirect capture imaging, how are the elements arranged?

In indirect capture imaging systems, the arrangement of the elements plays a crucial role in how the imaging process occurs. In this context, cesium iodide (CsI) is utilized as the scintillator material that converts incoming x-ray photons into visible light. This visible light is then detected by a layer of amorphous silicon, which functions as the photodiode array.

Having CsI on top of the amorphous silicon allows for efficient conversion and detection of x-rays. The CsI layer is structured to maximize light output and, as the light is emitted, it travels down to the amorphous silicon layer, where it is converted to electrical signals. This layered setup contributes to the overall sensitivity and resolution of the imaging system, enhancing the quality of the obtained images.

In this configuration, the geometry works optimally. The scintillator needs to be on the uppermost layer to effectively utilize the x-ray radiation and convert it into light, while the amorphous silicon layer is positioned behind, ready to capture that light to generate the necessary electrical signals for image formation.