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.
