Ch. 6 Breast Imaging Mammography Flashcards
means on the other side of the body
contralateral
is the device that receives the energy of the x-ray beam
detector
the range of underexposure or overexposure that can occur while still producing an acceptable image
exposure latitude
how much do digital receptors correct for underexposure and overexposure
50% under 100% over
the most inferior aspect of the breast where the breast attaches to the anterior chest wall
inframammary fold or crease
means on the same side
ipsilateral
the imaginary line running perpendicular from the pectoral muscle to the nipple in both the craniocaudal (CC) and mediolateral oblique(MLO) projections
posterior nipple line (PNL)
refers to the subject or part being radiographed and the result of differential absorption of the radiation by the part.
subject contrast
anatomy with high subject contrast
bone and soft tissue
anatomy with low subject contrast
breast
the method used to localize a lesion in the breast
triangulation
a measure of the percentage of energy that strikes a receptor material that is actually absorbed by the receptor
absorption effeciency
converts analog signal from the image receptor/detector to a digital signal for the computer to manipulate for processing, display, and storage
analog-to-digital converter (ADC)
scans the image receptor with a laser beam to initiate the emission of light.
computer reader or CR
the percentage of energy absorbed by a receptor that is converted to usable output
conversion effeciency
the term used to describe a spherical, fluid-filled structure
cyst
a rare genetic disorder characterized by the development of skin lesions, multiple benign hamartomas, and neoplastic growth throughout the body
Cowden’s syndrome
the product of absorption and conversion efficiency
detective quantum efficiency (DQE)
the percentage of energy that strikes a receptor and results in a useful output signal
detective quantum efficiency (DQE)
measures how efficiently a digital detector can convert the remnant beam to useful data
detective quantum efficiency (DQE)
higher detective quantum efficiency (DQE) means _________ patient dose
lower
are vacuum tubes with two electrodes: a cathode and an anode
diodes
in digital imaging is determined by the “window” and “level” of the displayed region of the breast
display contrast
the range of intensities that are displayed
window
the range of values over which a system can respond and is known as the gray-scale range.
dynamic range
refers to the number of shades of gray that can be represented in each pixel and represents the receptors ability to respond to different exposure levels
dynamic range
the range of underexposure or overexposure that can occur in producing an acceptable image.
exposure latitude
what is the percentage of under and over exposure that is acceptable for an analog image
30% underexposure and 50% over exposure
describes how much of the patient is imaged in the matrix
Field of view (FOV)
is equal to the pixel size x the matrix size
Field of view
is a rare hereditary condition in which individuals are predisposed to multiple cancers, caused by an alteration in the p53 tumor supressor gene
Li-Fraumeni syndrome
refers to the layout of cells in rows and columns
matrix
the ability of the detector system to transfer its spatial resolution characteristics to the image of the available spatial frequencies to produce an image that is exactly like the object.
Modulation transfer function (MTF)
the random background information that is detected but does not contribute to the image quality
noise
refers to the apparent displacement of an observed object when it is imaged from two or more different points
parallax
a material that, when irradiated, produces free electrons.
photoconductor
the release of stored energy within a phosphor or photostimulable plate by stimulation with visible light
photostimulated luminescence (PSL)
the process by which certain materials emit a flash of light in response to the absorbtion of ionization radiation.
scintillation
inorganic crystals that respond to ionization radiation by scintillation
scintillation phosphors
measures the ability to respond to or register small changes or differences
sensitivity
a comparison of the strength of the information in the digital image to the strength of the noise in the image
Signal-to-noise ratio (SNR)
In DR, images will have more signal strength at ___ spatial frequencies
low
increased noise results in ______ contrast
decreased
measured in line pairs per centimeter or line pairs per millimeter
spatial frequency
what size objects are able to be imaged using high spatial frequency?
small objects
______ spatial frequencies also give better spatial resolution
higher
the ability to distinguish and separate between two adjacent structures in the image.
spatial resolution
the quality of being precise rather than general. an imaging system that is highly specific can effectively differentiate between normal and abnormal changes within the breast
specificity
lying face up or on the back
supine
the process whereby the technologist postprocesses the image, allowing only a “window” of the entire dynamic range to be viewed on the computer monitor.
windowing
controls the brightness display
window level
controls the brightness difference displayed, or contrast
window width
