In radiology, TFT stands for Thin Film Transistor, a crucial component in digital radiography systems, specifically in indirect flat panel detectors.
TFTs are used to read out the electrical charge produced when X-rays interact with a scintillator (a material that emits light when exposed to radiation). This light is then converted to electrical charge which is captured and read out by the TFT array. Think of the TFT array as the "readout" or "capture" layer in digital x-ray systems, much like the sensor in a digital camera.
Here's a breakdown of their role:
-
Function: TFTs act as switches, controlling the flow of electrical charge from individual detector elements (pixels) in the flat panel. Each pixel has its own TFT.
-
How it works: When X-rays strike the scintillator, light is produced. This light then interacts with a photodiode layer. The photodiode converts the light into electrical charge. The TFT then selectively releases this charge, pixel by pixel, allowing it to be read and converted into a digital image.
-
Analogy: The process is similar to how transistors control individual pixels in LCD screens. In both applications, TFTs enable precise control and readout of individual elements in a display or detector.
-
Role in Digital Radiography: TFT arrays are a fundamental part of indirect digital radiography (DR) systems. These systems offer advantages over traditional film-based radiography, including:
- Faster image acquisition
- Digital image storage and manipulation
- Reduced radiation dose for patients
Therefore, in radiology, a TFT is a vital component within the flat panel detector, responsible for accurately reading the electrical signals generated after X-ray exposure, enabling the creation of a digital radiographic image.
