5 Medical Imaging Informatics Flashcards
represented by physical quanity whose allowed values are continuous
Analog form of data
number or other unit of infor such as letter of alphabet is represented by a sequence of digits, each of which is limited to a defined number of values
Digital form of data
- rectangular sometimes square array of picture elements
- its size must be half or less than the size of he smallest object to be seen
pixel
- largest number that can be stored in a single pixel is determined by ______
- 1 byte (8 bits)
- 2 bytes (16 bits)
- the no of bits or bytes used for each pixel
- 255 maximum number
- 65,535 maximum number
- reads or writes data in any order
- accesses data in a searial manner only
- random access (solid state memories, magnetic diskc, optical disks
- sequential access (magnetic tape)
Photometric quantity descibing thee brightness of a monitor.
rate of light nergy mitted or reflected from a surface per unit area, per unit solid anlee, correected for he photopic spectral sensitivity of the human eye
candela per square meter (cd/m2)
Luminance
ACR Technical Standar for Electronic Practice of Medical Imaging Maximal luminance for workstation: for mammography for optimal contrast
- at least 171 cd/m2
- at least 250 cd/m2
- at least 450 cd/m2
Gray scale LCD monitors provide about ===== times larger maximal luminances than color LCD
3X
BECAUSE RED, GREEN AND BLUE FILTERS IN COLOR lcdS ABSORB LIGHT OT CREATE COLOR IMAGES
minimal luminance of a monitor, measured in total darkness, entire screen black
black level
maximal luminance divided by the black level
contrast ratio
stray light from the face of the monitor that occurs when an image is displayed
veiling glare
Typical Radio Image formats PET Digital Fluoroscopy Xray CT MRI Utz
pixel format bits per pixel
- 128 to 336 16
- 512 or 1024 8 to 12
- 512 12
- 64 to 1024 12
- 512 8
luminance produced as a function of the magnitude of the digital or analog signal sent to the monitor
Display Function
dicom
gsdf
Digital Imaging and Comunications in Medicine
Grayscale Standard Display Function
Goals of DICOM GSDF
Which on is not achieved
- Provide applications with a predictable transformation of digital pixel values
(called “presentation values,” abbreviated as “P-values”) to luminance - similar display of contrast on display monitors and
printed media - provide perceptual linearization, that is, equal differences in the
pixel values received by the display system should be perceived as equal by the
human visual system (NOT ACHIEVED)
color used to display radiographic images
False color images
Advantage of Medical-grade monitors
- Much higher maximal luminance
- More uniform luminance
- Smaller pixels, providing higher spatial resolution
- Wider viewing angles, due to different LCD technology
- More than 8 bits for digital driving levels (grayscale monitors) or more than 8 bits
each for the digital driving levels for red, green, and blue (color monitors), to
display subtle contrast differences - Automatic luminance stabilization circuits to compensate for changing backlight
intensity - Hardware and software for implementing the DICOM GSDF
- Ability to monitor display monitor luminance and GSDF calibration over a network
multiformat laser cameras
most ___ camera emit infrared light
- ypically contains a microprocessor; an image memory; an analog-todigital converter; a laser with a modulator to vary the intensity of the beam; a rotating
polygonal mirror to scan the laser beam across the film; and a film-transport mechanism
to move the film in a linear fashion so the scanning covers the entire film. Each sweep of
the laser beam across the film records a single row of pixel values
Laser Imagers
- computeer on a network that provides service to other computers
- a comp with large array of magnetic disks that proides data storage for other comps
- server
- file server
- a computer on a network that makes use of a server
- client computer provides mroe information processing and the function of the servier is mainly to store information
- most info processing by server and client displays info
- clent
- thick client
- thin client
Physical Connections
- coaxial cable and copper wiring
- ________________ not affected by electrical interference and lower error rates, even in great distances
Optical fiber cables
divided info to be transmtitted
packets
standards for communication over a network
Network protocols
- Each device on a network whether a computer or switching device
- communication pathways between them (with a unique number)
node
link (network address)
max data transfer rate
max data transfer rate ACTUALLY ACHIEVED
- bandwidth
- throughput
time delay of a transmission bet 2 nodes
latency
store packets, read destination address and send - store and forward method
packet switching
packet-based suite of protocols used by many large networks and the internet
- Transmission Control Protocol
- Internet Protocol
Internet Protocol Suite or TCP/IP
OSI model
Layer 5 to 1 Application Transpot Network Data Link Physical
connectionless protocol or best effort protocol
IP
performs fx of 3 lowest network levels: physical, data link ad network
Router
- international network of networks using TCP/IP protocol
- use TCP/IP protocol within a single company or org
Internet
Intranet
Other internet protocols
- FTP
- HTTP
File Transfer Protocol
Hypertext Transfer Protocol
- PACS; system for storae, transfer and display of radioogical images
- transmission of such images fo r viwin at a remote site
- Picture Archiving and Communications Systems
- Teleradiology
HIS
RIS
EMR
Hospital information system
Radiology information system
Electronic medical record
device that uses light source and one or or light detector to measure the light transmitted through individual areas of fil an form a digital image depicting the distribution of optical density in the film
Film digitizers
