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PRI 2 Unit 3 Terms

SJC PRI 2 Unit 3 Willis

fill in the blankblankety-blank blank
____ ___ Location on a digital image number scale at which the levels of grays are assigned. It regulates the optical density of the displayed image and identifies the type of tissue to be imaged. Window Level
_____is the amount of luminance (light emission) of a display monitor. Brightness
____ ___ is the ability of the image receptor to distinguish between objects having similar subject contrast. Contrast Resolution
____ ____ refers to the range of exposure intensities an image receptor can accurately detect. Dynamic range
_____ ____ is a numeric value that is displayed on the processed image to indicate the level of x-ray exposure received to the digital image receptor. Exposure Index
_____ ____ Measure of resolution; usually expressed in line pairs per millimeter (lp/mm). Spatial Frequency
_____ ____ is the amount and energy of the x-rays reaching an area of the image receptor. Exposure Intensity
___The number of different shades of gray that can be stored and displayed by a computer system. Greyscale
____ ____ how often the analog signal is reproduced in its discrete digitized form. Sampling Frequency
___ _____ Specific number of gray levels or digital image numbers assigned to an image. It determines the gray scale rendition of the imaged tissue and therefore the image contrast. Window Width (contrast)
____ ___ Ability to image small objects that have high subject contrast. Spatial Resolution
A __is a graphic representation of a data set. The x-axis represents the _____ of exposure, and the y-axis represents the ___ of pixels for each exposure level. Histogram; amount; incidence (number)
The computer analyzes the histogram using processing algorithms and compares it with a pre-established histogram specific to the anatomic part being imaged. This process is called _____ ___ Histogram Analysis
____ determines the range of the histogram data set included in the displayed image. Values of interest
Histogram analysis is also employed to maintain consistent image ___despite overexposure or underexposure of the IR. This procedure is known _____ ____. Brightness; automatic rescaling
____ _____ Occurs during histogram analysis and is employed to maintain consistent image brightness despite overexposure or underexposure of the digital image receptor. automatic rescaling
The _____ _____ provides a numeric value indicating the level of radiation exposure to the digital IR. Exposure Indicator
The ____ image is stored as digital data and must be processed by the computer for viewing on a display monitor. latent
Matrix: combination of ____ and ___ rows; columns
____: "picture elements" or smallest component of matrix. Pixels
(pixel) Recorded as a single numerical value representing a ___ level on a display monitor. brightness
(pixel) Location in the matrix corresponds to a/an ____ within the patient or ____ area; volume
Digital image quality is improved with a larger matrix size that includes a ___ number of ___ pixels. greater; smaller
Larger matrix results in: Computer processing time will___ (increase/increase) increase
Numerical value assigned to a pixel is determined by the relative ___ of x-rays passing through the volume of tissue. attenuation
_____ or number of bits (2n) determines the number of shades of gray that can be displayed. pixel bit depth
The____ the number of pixels in an image matrix, the smaller their size. greater
Pixel ____: number of pixels per unit area. Decreasing this will ____ (increase/increase) spatial resolution. density; decrease
_____ ____: distance measured from the center of a pixel to an adjacent pixel. Increasing this will ___ (increase/increase) spatial resolution. pixel pitch; decrease
Spatial resolution is limited to the __ of the pixel. size
An image composed of ___ sized pixels has improved spatial resolution. smaller
Spatial frequency is defined by the ___. unit of line pairs per milimeter -lp/mm
Small objects have ____ (higher/lower) spatial frequency and large objects have ____ (higher/lower) spatial frequency. higher; lower
___ the number of ____ resolved in the imaging system results in improved spatial resolution. increasing; lp/mm
A ____relationship exists between window level and image brightness on the display monitor. Increasing the window level ___ the image brightness; decreasing the window level ___the image brightness. direct; increasing, decreasing -indirect relationship to pixel value (low = white, high = dark) move the window level towards the pixel value you want to see better!)
____ ___provide the means to alter the original pixel values to improve the brightness and contrast of the image. lookup tables
With digital, the computer creates a __ of the data set, a graph of the exposure to the ___ elements and the prevalence of the exposures within the image. it is compared with a stored histogram model for the part; VOIs are identified - image is displayed. histogram; pixel
A narrow (decreased) window width displays ___ radiographic contrast, whereas a wider (increased) window width displays ____ radiographic contrast. high; low
____is a technique that can remove superimposed structures so that the anatomic area of interest is more visible. subtraction
_ is a post processing technique that alters the pixel values to increase image contrast. contrast enhancement
___ ___ is a post processing technique that improves the visibility of small, high-contrast structures. __ __ may be slightly increased. edge enhancement; image noise
___ is a post processing technique that reverses the grayscale from the original radiograph. inversion
__is a post processing technique that suppresses image noise (quantum noise). __ is degraded. smoothing; spatial resolution
_____ is a computer system designed for digital imaging that can receive, store, distribute, and display digital images;____ and____ are computer systems that provide medical information. PACS-picture archival&communication systems; RIS-radiology information systems; HIS-hospital information systems
____is a communication standard for information sharing between PACS and imaging modalities. DICOM- digital Imaging and communications in medicine
____ is a communication standard for medical information. HL7- Health Level Seven Standard
Created by: paigeduh