IP
what is modulation transfer function?
describes the contribution of all system components towards total resolution. Resolution is best as the MTF value approaches 1
what is region of interest (ROI)?
boundaries of an object on an image.
what is:
ability to alter the receptor exposure and contrast of a digital image following processing
windowing.
diameter of the image reconstruction is called the ________?
field of view (FOV)
window level determines ________?
brightness or density
What does an MTF value of 1 represent?
100 or the best MTF value, it can never go over 1
in regard to electronic cropping or masking, what is stitching?
stitching images together to combine multiple images for anatomy that is too large for a single exposure, resulting in a seamless image.
How is matrix size determined?
rows x columns= matrix size
when the FOV is increased for a fixed matrix size, the size of each pixel is ________?
increased proportionally.
window level also determines the ________?
type of tissue being imaged
what is post-processing?
image manipulation completed by the technologist using various user functions.
what exams is stitching typically employed?
scoli series or bone length
what does matrix size determine?
total number of pixels in the image matrix
volume of tissue imaged is given a value called __________?
volume element or voxel
in CT imaging, window levels of _______ best images abdominal tissue?
50
what is brightness?
intensity of light that represents each pixel on the monitor.
how can ambient light on an image be reduced?
by shuttering, which removes or replaces the background.
what happens as the total number of pixels increases?
spatial resolution increases.
short grayscale = _________?
short-scale contrast
500
what is contrast?
differences in brightness (light and dark areas on an image).
what controls pixel brightness and contrast in digital imaging?
window level
what value is assigned to each pixel?
numeric value (CT or Hounsfield unit) based on receptor exposure in the pixel
long grayscale=_________?
long-scale contrast
what does window width determine?
the contrast (grayscale) presentation of the tissue under examination.