crdr 5 Flashcards
type of image such as paintings and printed photographs. continuous
analog image
recorded as multiple numeric values and are divided into an array of small elements that can be processed in many different ways.
digital image
- In digital radiography, analog signals are converted into numbers that are recorded.
- Digital images are formed through multiple samplings of the digital signal rather than the one single exposure of an analog image.
important characteristics of digital image
spatial resolution
contrast resolution
noise
dose efficiency
smallest element in digital image
pixel
- Contains the smallest divisible component of a digital image (bit).
- Has discrete values (whole number).
pixel
Directly related to the amount of spatial resolution or detail in the image.
pixel size
Number of bits within a pixel. Represents the gray level.
pixel bit depth
A square arrangement of numbers (pixel values) in columns and rows.
matrix
in digital imaging, it is the numbers (pixel values) in columns and rows
matrix
Each box within the matrix also corresponds to a
- specific location in the image and
- specific area of the patient’s tissue.
Amount of body part or patient included in the image.
field of view (FOV)
pixel size changes when matrix size/FOV changes
changes in FOV will not affect the size of matrix
amount of exposure received by the IR, not by the patient.
exposure indicators
UNG MGA TABLE SA MODULE LINTIK KA REVIEWHIN MO MARAMI YON
standard units of measure
- standard radiation exposure (KSTD)
- Indicated equivalent air kerma (KIND)
- Target equivalent air kerma value (KTGT)
- Deviation index (DI)
the difference between the actual exposure (KIND) and the target exposure (KTGT), except that is expressed in a logarithmic fashion.
deviation index
a set of values, established by either the system manufacturer or the system user, that represents an optimal exposure for each specific body part and view.
target equivalent air kerma value
measurement of the radiation that was incident on the IR for that particular exposure.
indicated equivalent air kerma
Derived from reading the pixel values produced by the exposure on an IR.
Known as for-processing pixel values (Q).
indicated equivalent air kerma
a standard exposure typical of that imaging receptor system.
standardized radiation exposure
used to ensure that the equipment is functioning appropriately.
standardized radiation exposure
appearance on the display monitor of the computer and is a function of the monitor’s ability to emit light through the surface of the display. LUMINANCE
brightness
