LECTURE 14 Flashcards
TV MONITOR
DISPLAY (CATHODE RAY TUBE)
RASTER SCAN
ELECTRON BEAM DIRECTED IN FIXED PATTERN OF HORIZONTAL SWEEPS ACROSS SCREEN. (LEFT TO RIGHT AND TOP TO BOTTOM)
INTERLACED DISPLAY:
TYPICAL DISPLAY
TIME
FRAMES
- 525 HORIZONTAL CLOSELY SPACED LINES, WRITES FIRST=ODD LINES, SECOND=EVEN LINES.
- 1/30 OF A SECOND FOR 1 FRAME
- 30 FRAMES + FOR FLICKER FREE IMAGE
NON INTERLACED DISPLAY:
- PROGRESSIVE.
- WRITES LINES IN SEQUENCE
- GREATER NUMBER OF HORIZONTAL LINES. (1000 OR MORE)
- MORE PIXELS
- BETTER SPACIAL RESOLUTION,
HIGH RESOLUTION MONITOR.
ADJUSTS THE RANGE OF ECHO BRIGHTNESS TO DARKNESS.
CONTRAST
- USES PHOTOGRAPHIC EMULSION FILM.
- STANDARD DEVELOPER USED.
MULTI IMAGE CAMERA.
- USES PHOTOGRAPHIC EMULSION FILM.
- DEVELOPS FILM USING LASER TECHNOLOGY.
LASER PRINTER.
- USES HEAT SENSITIVE PAPER.
- SMALL HEATING ELEMENTS IN PRINTER CARRY ECHO INFO AND RECORD IT TO HEAT SENSITIVE PAPER.
THERMAL PRINTER.
- USES HEAT SENSITIVE PAPER.
- USES HEAT TO STIMULATE RELEASE OF COLOR DYES ONTO HEAT SENSITIVE PAPER.
COLOR THERMAL PRINTER.
HOW IS M MODE OR SPECTRAL DOPPLER INFORMATION RECORDED?
STRIP CHARTS FIBER OPTIC (PROCESSING)
MAGNETIC RECORDING DEVICES
VIDEOTAPE CASSETTE
FIBER OPTIC
- DIGITAL FORMAT STORAGE USED FOR DIGITAL ARCHIVING.
- COMBINES READ/WRITE CAPABILITIES OF MAGNETIC TECHNOLOGY WITH STORAGE CAPABILITIES OF OPTICAL MEDIA.
MEGNETO - OPTIC-L DISC.
- DIGITAL METHOD OF STORING AND TRANSMITTING IMAGES.
- ACQUISITION, DISPLAY, ARCHIVING, HARDCOPY COMPONENTS LINKED BY LAN.
- MAKES TELERADIOLOGY POSSIBLE.
PACS (PICTURE ARCHIVING AND COMMUNICATIONS SYSTEM)
AKA DIN, IMACS
A MODE
-1 DIMENSIONAL
-Y AXIS = AMPLITUDE OF ECHO
X AXIS = DEPTH OF ECHO
-EXACT DIMENSION MEASUREMENTS
-NO MOVEMENT RECORDED.
M MODE
- RECORD TIME AND MOTION
- X AXIS (H) = TIME
- Y AXIS (V) = MOTION
- EXCELLENT TEMPORAL RES.
- EXACT MEASUREMENTS ON MOVEMENT
- 1 DIMENSION
- NO CROSS SECTIONAL IMAGE
B MODE
- REAL TIME 2D GRAY SCALE
- DOTS = ECHO AMP.
- DOT LOCATION RELATES TO REFLECTOR POSITION
- X AXIS = LATERAL POSITION OF ECHO
- Y AXIS= DEPTH OF REFLECTOR
- REAL TIME CROSS SECTIONAL IMAGING
- TEMPORAL RES. LIMITED BY FRAME RATE.D
3D IMAGING
- MORE SURFACE DETAIL = MORE DIAGNOSTIC INFORMATION
- LOWERED TEMPORAL RES.
- DIFFICULT TO IMAGE DEEPER STRUCTURES
FACTORS THAT AFFECT TEMPORAL RES.
- LINE DENSITY
- IMAGING DEPTH
- SECTOR SIZE
- MULTIPLE FOCUSES
(TYPICAL FR = 30+ FRAMES/S)
THE GREATER THE IMAGING DEPTH,
THE LOWER THE FRAME RATE. (PRF LESS)
SPEED OF SOUND IS LIMITING FACTOR.
NUMBER OF LINES MAKING UP A FRAME:
LINE DENSITY.
MORE LINES =
WORSE TEMPORAL RES., BETTER SPACIAL RES.
LARGER SECTOR ANGLE
MORE LINES AND TIME, LOW FRAME RATE, WORSE TEMPORAL RES. AND VISE VERSA.
MULTIPLE FOCAL ZONES
-MULTIPLE PULSES NEEDED = LINES TAKE LONGER TO FORM = INCREASED TIME = LOWER FRAME RATE- WORSE TEMPORAL RES. BUT BETTER RES.
PENETRATION DEPTH (CM) x # OF FOCAL ZONES x LINES PER FRAME (EQUAL OR LESS THAN) 77,000
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