Mammography Equipment Ch. 5 Flashcards
describes the angle between the surface of the target and the vertical line, perpendicular to the image plate
anode angle
refers to the current in which electrons oscillate back and forth through a conductor in alternating positive and negative directions
alternating current
the rate of changing direction
frequency (Alternating Current)
measured in Hertz
frequency
the number of forward-backward cycles per second
hertz
are produced when an outer projectile electron is slowed by the electric field of the target atom nucleus
bremsstrahlung x-rays
refers to how dark the image is
brightness
term used to replace ‘density’-which is used to describe analog images
brightness
what is the brightness of a digital image controlled by
the processing software
is produced when an outer shell electron fills an inner shell void in the atom of an element
characteristic radiation
if the outer shell electron fills the void in the K shell, the x-ray emission is termed ______.
K Characteristic X-rays
describes the interaction between low-energy electrons and atoms. the x-ray loses no energy but changes direction slightly
coherent/classical scattering
occurs when moderate energy x-rays interact with an outer shell electron and eject the electron from the atom. the x-ray loses energy and changes direction.
compton scattering
during compton scattering, the ejected electron is called __________.
compton electron
the ability to image two separate objects and visibly detect them as seperate entities
resolultion
refers to the minimum difference between two adjacent structures that can be detected in the image as separate entities
contrast
in digital imaging, what is contrast dependent on?
pixel size
refers to a set of computer software standards that permit wide range of digital imaging programs to understand each other
DICOM
a storage option in digital imaging
DLT (Digital linear tape)
is electron flow in one direction along a conductor. the currect is either always positive or always negative
Direct Current
the area projected onto the patient and the image plate, and it is the value given when describing the focal spot of the mammography units
effective focal spot
convert a conventional radiograph to a digital version via a scanning device
film digitizers
describes the number of lead strips per centimeter in a grid
grid frequency
what is a common range of grid frequencies for mammography?
30-50 lines/cm
the height of the lead strips divided by the distance between the strips
grid ratio
what are some common grid ratios in mammography
4:1 or 5:1
describes the process by which light is reflected back toward the emulsion after it passes through the emulsion and base
halation
the thickness of absorbing material necessary to reduce the x-ray intensity by half of its original value
half-value layer (HVL)
describes the intensity of light incident on a surface
illuminance
replaces the cassette used in analog imaging
image plate (IP)
what kind of technology is used in the imaging plate?
photostimulable phosphor (PSP)
the device that receives the energy of the x-ray beam
image receptor
replaces the screen/film system in analog imaging
image receptor
describes the brightness of a light source
luminance
is calculated by dividing the source-to-image receptor distance (SID) by the source-to-object distance (SOD)
magnification factor
an array of pixels in which each pixel is a sample of the image represented by a numerical value
matrix
the unsharp shadow or “blur” surrounding the image
pneumbra
the smallest component of the digital image
pixel (picture element)
is a storage option in digital imaging
RAID
the conversion of alternating current (AC) to direct current (DC)
rectification
may refer to any diode produced using thin film technology
thin-film transitor (TFT) or thin-film diode (TFD)
are photoconductors used to collect electrons
amorphous silicon or amorphous selenium
have amorphous silicon or amorphous selenium deposited on thin films
thin-film transitor (TFT) or thin-film diode (TFD)
states that the optical density produced on the radiograph will be equal when any combination of mA and exposure time is used as long as the product is equal
Reciprocity law
the ability to detect small objects with high subject contrast
spatial resolution
the ability to distinguish anatomic structures with similar contrast
contrast resolution
the emission of electrons from a hot cathode into a vacuum
thermionic emission
the ability to make medical images accessbile across multiple modalities and between different organizations
vendor neutral archives (VNAs)
