| Detector |
| The detector is an electronic receptor which converts an X-ray signal into an electronic, digital signal that can be displayed and manipulated on a computer. The detectors used by New Medical are manufactured from TFT panels. |
| Detector quantum efficiency (DQE) |
| Detector quantum efficiency is a measure of the system’s dose efficiency against its signal-to-noise ratio. It measures the system’s efficiency in detecting objects at certain frequency (lp/mm) with specific noise.
|
| Digital radiography (DR) |
| An advanced process of capturing X-ray signals using digital means and converting the X-ray signal to an electronic signal for display and manipulation. |
| Direct conversion |
| Direct conversion DR detectors convert the X-ray photons into an electronic signal via a one-to-one process. Direct conversion DR detectors most commonly use an amorphous Selenium (a-Se) layer for this conversion process. In this process an X-ray photon stimulates a Selenium proton, which is captured by an electrode, measuring its intensity, and converted into an appropriate electronic signal. |
| Dynamic range / contrast |
| Dynamic range is a measure of the amount of gray levels present in the image. Contrast is the absolute difference between the whites (bone) and blacks (tissue) on the X-ray. |
| Fill factor |
| Fill factor measures the percentage of a pixel being used as a receptor. |
| Film speed |
| Film speed is the measure of a photographic film's sensitivity to light. DR detectors inherently do not have a film speed, but many manufacturers make claims relating their optimum dose to film speed. |
| Image preview time |
| The time necessary after X-ray exposure before one image can be displayed on the acquisition software. |
| Indirect conversion |
| Indirect conversion DR detectors convert the X-ray photons into an electronic signal using scintillators. In this process an X-ray photon hits a scintillator, producing visible light. The visible light is captured by a photodiode, measuring its intensity, and converts it into an appropriate electronic signal. |
| Modulation transfer function (MTF) |
| Modulation transfer function measures the percent of the input (X-rays) are converted to output (image signal) at a specific frequency (lp/mm). |
| Pixel |
| The smallest functional unit of a TFT panel, usually measured in units of micrometers (μm). |
| Pixel size / pixel matrix |
| Pixel size measures the width of one functional TFT receptor circuit. Pixel matrix measures the total number of rows or columns of pixels on one detector. |
| Signal-to-noise ratio (SNR) |
| Signal-to-noise ratio measures the amount of interference, or noise, there is in the X-ray signal. Noise can come from a variety of factors, including inherent system noise, X-ray scatter, or similar distortions. |
| Spatial resolution: |
| Spatial resolution refers to the ability of a system to detect small, high-contrast objects (such as fractures or bone breaks), and is measured in linepairs per millimeter. |
| Thin-film transistor (TFT) |
| A thin-film transistor (TFT) is a special kind of field-effect transistor made by depositing thin films of a semiconductor active layer as well as the dielectric layer and metallic contacts over a supporting substrate, usually glass. |
