Ch. 10 Digital Image Receptors Flashcards
two groups of digital receptors are
computed radiography (CR) and direct radiography (DR)
what are the 4 parts of a CR system
- cassette
- photostimulable phosphor plate (PSP)
- plate reader
- computer workstation
what is the backing material of the CR cassette, used to absorb back-scatter
aluminum
what are the layers of the PSP plate
- protective layer
- phosphor layer
- reflective layer
- conductive layer
- support layer
what is the phosphor layer typically made of
barium fluorohalide with europium activator
what are the two types of phosphor layers
turbid or structures
phosphor crystals are randomly distributed
turbid
contains columnar phosphor crystals that resemble needles standing on end, packed tightly together
structured
when the electrons in the phosphor layer are ionized the ejected electrons are trapped in this
conduction band
this is what allows the phosphor to store x-ray energy as the latent image
europium
this detects the light that is released from the PSP during scanning and amplifies the light in the form of an analog image
photodetector
the amplified analog signal is converted to a digital signal by this
ADC
two categories of DR
direct capture and indirect capture
two different form of indirect capture
- CCD/CMOS
- TFT
CCDs are coupled with this
scintillator plate - cesium iodide
what does the scintillator plate act as
phosphor layer of CR - fluoresces when radiated
a sturdy, light-proof container for film. Also a sturdy protective container for the photostimulable phosphor plate in computed radiography
cassette
a light-sensitive semiconducting device that generates an electrical charge when stimulated by light and stores this charge in a capacitor
charge-coupled device (CCD)
a scintillator device made up of a crystalline silicon matrix
complementary metal oxide semiconductor
a digital imaging system that uses a cassette, a photostimulable phosphor plate, a plate reader, and a computer workstation to acquire and display a digital image
computed radiography system
a measurement of the efficiency of an image receptor in converting the x-ray exposure it receives to a quality radiographic image
detective quantum efficiency (DQE)
the physical component consisting of multiple detectors that efficiently absorb the transmitted radiation and accurately convert it to an electrical signal for display on a computer workstation
detector array
the process by which washing works; exposes the film to water that contains less thiosulfate than the film
diffusion
a common computer language that allows different systems of a picture archiving and communication system to communicate with each other
Digital Imaging and Communications in Medicine (DICOM)
a digital imaging system that uses a detector array in place of the Bucky assembly; the imaging-forming radiation is captured and transferred to a computer from the detector array for almost instant viewing at the control panel
direct radiography systems
a measurement of exposure in air, followed by a computation to estimate absorbed dose to the patient
dose area product (DAP)
the range of exposure intensities that an image receptor can respond to and acquire image data
dynamic range