FUNDAMENTALS

Flat Panel Detectors

A Flat Panel Detector or “FPD” is a specialized digital camera for taking X-ray images.

Unlike visual light, X-rays cannot be easily focused through a lens, therefore the camera’s active area needs to be as large as the picture you want to take.

Each FPD consists of two basic components, a sensor layer that captures the X-ray and a Thin Film Transistor array or “TFT”. A TFT array is a device most commonly used in displays for cellphones, TVs and computer screens.

Although FPDs are produced by many different companies and come in several different sizes, the current technology is identical from panel to panel.

Current Technology

The X-ray detector market is currently dominated by FPDs that utilize an indirect method of detection. These devices rely on a scintillator layer of either Cesium Iodide (CsI) or Gadolinium Oxysulfide (Gd₂O₂S) to convert X-ray into visible spectrum light. These photons are then detected by a specialized TFT pixel array with a photosensor built into each pixel.

Disadvantages

• Limited resolution due to light spreading
• Limited sensitivity
• Mature technology with few future improvements

 BREAKTHROUGHS

Innovative Processing Techniques

Polycrystech has developed SegPix, a new CsI scintillator technology that provides a light barrier between pixel areas in the scintillator layer.

The segmentation prevents light spreading between pixels which increases and preserves spatial resolution even in thicker layers.

Advanced light capturing techniques are also integrated to improve signal quality and DQE.

Additionally, SegPix offers reduced afterglow to provide ultra-high frame rate capabilities.