full field digital mammography Flashcards
5 year relative survival rate-
stage 0
stage 1
stage 2
stage 3
stage 4
0-100%
1-100%
2-93%
3- 72%
4- 22%
a parameter adjust the gray scale or what is called contrast
window width
a parameter adjust the density of the image or blacks; brightness
window level
first converts the xrays into visible light with a scintillator. the visible light is then converted into an electrical signal
indirect capture
uses a scintillator made of cesium iodide to convert xrays into light which is then captured by the photodiodes
amorphous silicon
when the xrays are not converted into light but directly into an electrical signal
direct capture
the scintillator is replaced with the amorphous selenium plate that converts the xray photons directly onto electron hole pairs
amorphous selenium
the number of shades of gray that a detector can capture
contrast resolution
capable of capturing thousands of shades of gray (far more than the human eye can appreciate). this permits the imaging of areas that would otherwise be under or overexposed on conventional film
high contrast resolution
small computer chips which create a digital image
charged coupled device CCD
a unit of length equal to one millionth of a meter
micron
the basic unit of the composition of an image on a tv screen, computer monitor, or similar display
pixel
center of one pixel to the center of another pixel. one way a pixel matrix is measured
pixel pitch
a substance that glows when hit by high energy particles or photons
scintillator
1000:1- wide in digital allowing a broader range of exposures that will produce an acceptable image.
latitude
information single binary digit like 0 or 1
BIT
___ bits = 1 byte
8
increasing/widening the window width range in pixel values will give ____ contrast and ____ gray toning
less, more
decreasing/narrowing the window width range in pixel values will give ____ contrast and ____ black and white
high, more
another name for window level
window centering
increasing the window level/center results in _______ image
darker/blacker
a process where the detector looks at variations in pixel density across the image and then estimates the thickness of the breast at each pixel
thickness equalization/compensation
an expression of the efficiency of an imaging system’s transfer from its input to its output of both signal and noise
detective quantum efficiency DQE
expressed as a percentage. the measure most representative of image quality in terms of an observer’s ability to detect objects of interest in an image
dos efficiency
is now the most important parameter in digital mammography process
detective quantum efficiency DQE
detector performance is commonly quantified by 2 metrics
modulation transfer function MTF
detective quantum efficiency DQE
a measure of resolution/spatial frequency response
modulation transfer function MTF
a measure of dose efficiency
detective quantum efficiency DQE
a measure of the transfer of modulation (or contrast) from the subject to the image
modulation transfer function MTF
a computer chip that is an analog to digital converter ADC
charged coupled device CCD
accepts a continuously varying output signal (analog) and converts it to a discrete set of digital numbers
analog to digital converter ADC
_____ serve 2 roles: conduct light from the phosphor to a charge-coupled device array, which converts light into an electronic signal that is digitized; stop much of the radiation that is not absorbed by the phosphor and thereby protect the CCD from the radiation damage that would result from direct exposure to xrays
fiber optics
a scintillator layer (cesium iodide) is doped with thallium to capture the xray energy and convert the xray into light; then thin-film diodes convert the light photons into electronic signals that are captured using TFT’s
indirect detectors
xrays are absorbed by a photoconductor (amorphous selenium) and generate a signal. photoconductor is made thick in order to stop the majority of incident xrays
direct detectors
___% of the xrays are useful in direct detectors, compared to film screen that counts for ___% of efficiency
95,50-70
spatial resolution in digital imaging is _____ than f/s and ____ in contrast resolution
lower,higher
an area comprised of the number of pixels in the x and y coordinates
matrix
the depth (matrix) is measured in what
bits
the depth (matrix) is measured in bits and known as the
different shades of gray
6 bit image = __ shades of gray
64
7 bit image = __ shades of gray
128
8 bit image = __ shades of gray
256
10 bit image = __ shades of gray
1024
3 things the pixel size affects
storage
transmission time
archival quality of the image
