Image Science
How many bits are in a byte?
8 bits in 1 byte
In computer language a single binary digit, 0 or 1, is called a bit.
The bit represents zero or one
In CR, where is the latent image stored?
In the Photostimulable Phosphor (PSP) Plate
In digital radiography, what is the brightness of the image is determined by?
Pixel values
What is Dose Creep?
The gradual increase in patient dose due to overexposure being masked by image processing
A computer has two principle parts- hardware and software.
The hardware is all of the physical components. Input/ output processing, memory, storage, and communications.
What is the function of computer software?
Computer software consists of the programs that tell the hardware what to do and how to store and manipulate data
After how long does 25% of the latent image deteriorate?
8 Hours
True or False
CsI/CCD is an indirect DR process by which x-rays are converted first to light and then to an electronic signal
True
In what pattern does a CR reader scan and read the cassette?
In a Raster pattern
Which digits are included in the binary system?
0 and 1
What effect is prevented by flooding the erased imaging plate with bright light?
Ghosting
The dynamic range determines what about the image?
The dynamic range determines the degree of contrast resolution in the image
When will a photostimulable phosphor in a metastable state will emit light?
Immediately, when stimulated by light, and over time
The exposure index is linear across most imaging manufactures
False.
Almost all manufactures have their own scale of exposure index and unique display
The output signal from the photostimulable phosphor plate is converted from analog to digital by what?
Computer controls
In digital radiography, spatial resolution is improved with increased what?
Matrix size
Decreased pixel size, increases spatial resolution
Histogram analysis errors occur if
Incorrect anatomy is included
Poor collimation
Wrong exam selected
Modern day computers use what to store information?
Silicon chips
Computed radiography screens respond to radiation with what?
Photostimulable Luminesce
Does DR have a higher or lower DQE than CR
DR has a higher DQE than CR
What computer language was the first modern programmers language?
FORTRAN (Formula Translation) developed by John Backus at IBM (1957)
It enabled programmers to use English-like statements instead of machine code
What is the form of radiology that allows for the transfer of images to remote sites for interpretation?
Teleradiology
What the four steps of creating an image with Computed Radiography?
Metastable state, stimulate, read, and erase
kVp- Controls contrast, higher kVp → lower contrast but more penetration
mAs- Controls image noise
Which is the primary factor affecting the Expsoure Index?
mAs is the primary factor affecting the exposure Index (Patient dose)
Name three operations in diagnostic imaging departments that are computerized
1. Image Acquisition/ Reception
2. Image Manipulation/ Processing
3. Image Management/ Storage (PACS)
What input/output devices are commonly used in radiology?
Input/Output PACS
Input hardware converts data into a form that the computer can use
Output hardware produces digital displays, audio, mathematic calculations, etc
Name three photostimulable phosphors
Usually made of phosphors from the barium fluorohalide family (e.g., barium fluorohalide, chlorohalide, or bromohalide crystals) with Europium*
Describe the Moire Effect
Grid's line frequency is similar and parallel to the sampling frequency of the CR reader's laser, it creates a wavy linear artifact
What is the difference between sampling and quantization?
Sampling is done prior to the quantization process. It determines the spatial resolution of the digitized images.
Quantization determines the number of grey levels in the digitized images.
Sample rate refers to the time domain resolution and quantization is related to the bit depth, a measure of resolution in the amplitude and level of noise.
What is the difference between machine learning and deep learning?
Deep learning is a subset of machine learning that utilizes multi-layered artificial neural networks to learn patterns directly from large, unstructured datasets. Required significant computing power for complex, autonomous tasks
What is the purpose of an optical filter positioned before the photodetector?
To only allow emitted light to reach the photodetector, while blocking the intense stimulated light.
Decreasing the signal to noise ratio
Define Pixel Pitch
The distance between pixels, measured from the center of one pixel to the center of the next
Define ALARA.
Why is this so important
As Low As Reasonably Achievable
Radiation dose is cumulative. It is important to use the lowest levels of exposure possible to produce an optimally diagnostic image