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Definition
| A graphical representation of exposures values collected from the imaging plate |
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| Plate is scanned Image location and orientation is determined. Size of the signal is determined. Value is placed on each pixel. |
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| Theorem states that when sampling a signal, the sampling frequency must be greater than twice the bandwidth of the input signal so that the reconstruction of the original image will be nearly perfect. |
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| Spatial frequency is greater than the Nyquist frequency and Information is lost and a Fluctuating signal is produced |
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| Images are produced that have uniform brightness and contrast regardless of the amount of exposure |
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| A table of the luminance values derived during image acquisition |
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Definition
| Refers to the range of exposures that can be used and still result in the capture of a diagnostic quality image |
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| Modulation transfer function (MTF) |
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Definition
| The ability of a system to record available spatial frequencies |
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Definition
| Contrast-enhancement parameters convert the digital input data to an image with appropriate brightness and contrast. |
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| When the signal is obtained, averaging of the signal occurs to shorten processing time and storage |
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| Also known as low-pass filtering.Results from averaging of the frequency of each pixel with surrounding pixel values to remove high-frequency noise |
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Definition
| Controls how light or dark the image is. |
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| Controls the ratio of black to white, or contrast. |
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| used to blacken out the white collimation borders. |
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| Stitching is used for anatomy or areas of interest too large to fit on one cassette |
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Definition
| function allows the quality control technologist to select one or more local computers to receive images |
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Definition
| Consist of a photoconductor such as amorphous selenium (a-Se), which converts the x-ray photons directly into electrical signals.This category also includes silicon and CCD detectors. |
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Definition
| Is a thin layer of transistors on a substrate (support material) Will detect either light or electrons |
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Term
| field-effect transistor (FET) or silicon TFT |
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Definition
| Isolates each pixel element Reacts like a switch to send the electrical charges to the image processor |
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Definition
| X-rays photons strike a scintillator that produces light then, That light strikes the amorphous silicon allowing the conduction of electrons into the detector |
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| Amorphous Silicon Detector |
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Definition
| Uses thin films of silicon integrated with arrays of photodiodes coated with a crystalline cesium iodide scintillator or a rare-earth scintillator (terbium-doped gadolinium dioxide sulfide). |
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Term
| Complementary metal oxide silicon (CMOS) systems |
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Definition
| Uses specialized pixel sensors that, when struck with x-ray photons, convert the x-rays into light photons and store them in capacitors |
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Term
| Detective Quantum Efficiency, or DQE |
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Definition
| How efficiently a system converts the x-ray input signal into a useful output image |
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Definition
| a wavy artifact caused by grid lines running parallel to the laser scanning motion |
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Definition
| Refers to the number of grid lines per centimeter or lines per inch |
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Definition
| The relationship between the height of the lead strips and the space between the lead strips |
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Term
| exposure indicator number |
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Definition
| The amount of light given off by the imaging plate is a result of the radiation exposure that the plate has received |
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Term
| S, or sensitivity, number |
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Definition
| For Fuji, Phillips, and Konica systems-The S number is the amount of luminescence emitted at 1 mR at 80 kVp, and it has a value of 200 |
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Term
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Definition
| Carestream-1 mR exposure at 80 kVp combined with aluminum/copper filtration yields an EI number of 2000 |
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Term
| lgM, or logarithm of the median exposure |
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Definition
| Agfa-An exposure of 20 µGy at 75 kVp with copper filtration yields an lgM number of 2.6 |
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| Automatic data recognition |
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Definition
| The image recording range is automatically determined |
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Definition
| The L value of the histogram is fixed, and only a small reading area is used |
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| Multiple Manual Selection Mode |
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Definition
| The technologist selects the area of interest, and the image is derived from the selected areas imaged in semiautomatic mode |
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Definition
| S and L values are fixed in that the user selects the S value, and the L value |
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Definition
| a very thin, tough, clear plastic for protection of the phosphor layer |
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Term
| Phosphor, or active, layer |
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Definition
| A layer of photostimulable phosphor that "traps" electrons during exposure. Usually made of phosphors from the barium fluorohalide. May also contain a dye that differentially absorbs the stimulating laser light to prevent as much spread as possible |
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Definition
| a layer that sends light in a forward direction when released in the cassette reader |
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Definition
| a layer of material that will absorb and reduce static electricity |
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Definition
| Newer plates may contain a color layer, located between the active layer and the support that absorbs the stimulating light but reflects emitted light. |
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Definition
| a semirigid material that gives the imaging sheet some strength |
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Definition
| a soft polymer that protects the back of the cassette |
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Definition
| Light Amplification by Stimulated Emission of Radiation |
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Definition
| refers to the movement of the imaging plate through the CR reader |
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Definition
| refers to the movement of the laser across the imaging plate |
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Definition
| amplifies the light and sends it to a digitizer. |
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Definition
| Refers to the amount of detail present in any image.Phosphor layer thickness and pixel size determines resolution in CR. |
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Term
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Definition
| is a reflection of the amount of light (photostimulable luminescence or PSL) emitted by the plate during the reading process and is related to the level of exposure received by the receptor |
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