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Digital Imaging A
Digital Imaging
Question | Answer |
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one of the two types of digital imaging systems that is cassette based, the body part is obtained using storage phosphor in the cassette | Computed radiography |
the process of acquiring images of the body using x-rays displaying them digitally, viewing and storing them on a computer complete file | Digital imaging |
one of the two types of digital imaging systems; is cassetteless. The phosphor is bonded to a flat panel detector built into the x-ray table or chest board | Digital radiography (DR) |
detectors convert the x-ray energy directly to an electric signal through an amorphous selenium detector | Direct conversion |
a two-step process in which the x-ray energy is first converted to light & then converted into electrical signal using a scintillator | Indirect conversion |
a device that glows when hit by the high-energy x-ray photons and often is made of cesium iodide | Scintillator |
a phosphor used in computed radiography (CR)plates to absorb the x-ray energy and store it until it is processed by a special unit and laser light | Photostimulable phosphor |
an extensive networked group of computers, services and archives the image | Picture archival and communication system (PACS) |
the further adjusting of any image of a body part with the use of computer software | Post processing |
image comprised of continuous shades of gray from black to white | Analog |
relates the number of line pairs in a given length as cm or mm (lp/mm); data is sampled from an exposed detector in computed radiography/detector element-size (del) | Sampling frequency |
an array of small picture elements (pixels) that forms a matrix; each pixel is recorded | Digital |
the ability if an imaging system to resolve and render on the image a small high contrast object; determined primarily by the number of pixels in an image & therefore the size of each pixel | Spatial resolution (digital) – |
the dimensions of the field of view (fov) with in patients body not the size of displayed image | Image size (digital) |
range of exposures over which a detector can acquire image data and display contrast comparable to film latitude; the number of gray shades that an imaging system can reproduce. | Dynamic range (digital receptors) |
smallest exposure change (signal) difference that can be captured by a detector controlled by the dynamic range of the detector and quantization | Contrast resolution (digital) |
an option of post processing to improve the film | Windowing |
a part of windowing that adjusts the brightness; it identifies the type of tissue to be in focus (soft tissue or bone) | Window level |
determines the gray scale rendition of that tissue & therefore the image contrast | Window width – (contrast) |
measure of x-ray absorption efficiency; variation in detectors which predicts their efficiency; absorption coefficient; | DQE Detector Quantum Efficiency |