RTE2457 Imaging II

There are 2 types of Digital Radiography.
1.__ __- Uses a photostimulable storage phosphor (PSP) inside a cassette.

2.__ __- Uses a detector built in to Bucky or inside a cassette (wireless)

Binary Machine Language

Computers operate using a binary (base 2) system
____ = off
____ = on

Each binary number is called a ___ “binary digit”

_____ - a unit of data (word) that contains 8 bits. Also is the unit most computers use to represent a character such as a letter, number, or typographic symbol.

_____ - A series of boxes displayed in a layout of rows & columns.

——- Each box is called a ___ that corresponds to a 2-dimensional location in the image (x & y coordinates)

A _____ represents a 3-dimensional volume of tissue (z coordinate)

The ____(_) is the overall dimension of the image matrix.
——- is determined by the size of the detector in digital radiography.
——- if remains constant but matrix size increases, the pixels must get ____.

Each pixel assigned a numeric value (_______) that represents a shade of gray or brightness level based on the attenuation characteristics of the volume of tissue x-rayed.

Bone attenuates (absorbs) x-rays to a large degree, so the pixel value will be ___, producing high brightness. (Low density)

Air attenuates x-rays to a lesser degree, so the  pixel value will be ____, producing low brightness (high density)

High brightness = ___ density
Low brightness = ___ density

___ ___ is the number of bias used to represent each pixel. The greater the __ __, the more shades of gray that can be displayed.

___ ___ refers to the range of values or number of gray shades that an imaging system can reproduce.

The 3 types of Image Processing Operations
1.____
2.____
3.____

____ - a graphical display of the pixel intensity distribution for a digital image.
- Is generated from the image data based on signal intensity from each pixel
- The shape corresponds to the specific anatomy and technique used for an exam.

On histogram 
_-axis represents the amount of exposure
_-axis represents the incidence of pixels for each exposure level

A computer analyzes the histogram to determine the ____ & _____.

A _____ is data stored in the computer used to manipulate the values of gray levels (contrast). It does this by substituting new values for each pixel during point processing.

___ ___ is why an underexposed or overexposed digital image may display with acceptable brightness on the monitor.

____ is a process that changes the contrast & brightness (density) of a digital image on the monitor. This is done through varying the numerical values of each pixel manually.

The ____ ___ is the range of brightness (densities) that will be displayed on a monitor. It is primarily used to control image ____

The ____ ____ is the center of the window width, or the midpoint of the entire range of brightness (densities) displayed on a monitor. It is primarily used to control image ___.

Narrow WW - ___ contrast
Wide WW - ___ contrast

Low window level - ___ brightness
High window level - ___ brightness

____ ____ - is a process used to sharpen the image by amplification of the frequencies of the area of interest.

____ - is a process used to intentionally blur the image
- low-pass filter applied
- Produces an output image with decreased noise & brightness level of pixels

___ ___ - is a process used to subtract a low-pass (blurred) image from the original image
- Suppresses some frequencies
- Produces a sharper output image

____ ____ - processes used to change the position or orientation of the pixels in the image

Factors that affect the quality of a digital image.
____ ___ - the degree of geometric sharpness of the structural lines (edges) recorded in the image.

____ - grainy or uneven appearance of an image

____ ___ ___ - a measure of the sensitivity & accuracy by which an image receptor converts the incoming data to the output device (monitor)

Spacial resolution 
Small pixels = ____ spacial resolution
Large pixels = ____ spacial resolution

Noise

___ ___ ___ - results from undesirable signals from the digital system that do not contribute to the image.

___ ___ ___ - results from an insufficient quantity of photons reaching the IR (mAs and/or kV set too low)

The ___ ___ is a comparison between the actual exposure & the proper exposure received by the IR.

PSP Plates
___ layer - base for the other layers 
___ layer - insulates plate from handling trauma
___ layer - active component of plate; holds photostimulable phosphors that are energized when exposed to x-rays
___ layer - grounds plate and absorbs light
__ __ layer - prevents light from erasing data on plate
___ layer - prevents light leak

Indirect Flat Panel - uses ___ ___ as a scintillator that emits light when struck by x-rays
—— ___ ___ transforms light into electronic signal

Direct Flat Panel - no scintillator; uses ___ ___ to convert x-rays directly into an electronic signal