4. The Instrument
While the ISS OxiplexTS is designed specifically for
Calibrated Multi-distance Measurements; the Imagent
can also be used for this purpose. However the Imagent
is more flexible.
7. Imagent Setup
Start the system
• Turn on the computer (if a Magma docking station is
used, it should be powered first.)
• Insure detectors are off (or covered)
Turn on instrument
• Start Boxy software
• “ Warm up ” system for 10-30 minutes
8. Imagent Setup
Start the system
• Turn on the computer
• Insure detectors are off (or covered)
• Turn on Imagent system
• Start software
• “Warm up” system for 10 minutes
9. Imagent Setup
Select Sensor
• Flexible or Rigid. The “rigid” muscle sensor is easier
to calibrate and more accurate. The “flexible”
sensors can be used in places the rigid sensor will
not work.(sensor must be continuous, even contact
with the skin)
• Select longer emitter-detector distances for thick
superficial layers
10. Imagent Setup
Attach Sensor(s)
1. Attach the detector bundle
2. Attach source-fibers to both diodes of two
wavelengths.Most ISS sensors have 8 and 1 detector
bundle, 4-source-detector distances
2-source-fibers at each distance (to support two
wavelengths.
Detector Source Fiber #
Bundle 1,5 2,4 3,5 4,8
Source-Fiber locations
11. Imagent Setup
Possible fiber attachments depends on the switch-
mode. There are multiple correct ways to attach the
source fibers.
Rules:
The 2 fibers connected to the same source-detector
distance group must be connected to diodes of two
wavelength.
No two diodes can have the same external mux #
(number/signal #). That is, two of the light source
used with one sensor can not be on at the same time.
The detector can only distinguish the signal form
diodes not simultaneously on.
12. Imagent Setup
While there are multiple correct ways to
attach the sensors, the software
setting must match and describe the physical
attachment .
16. Instrument/Sensor Check
• Start Data Acquisition (with sensor on cal. block).
• Adjust “Optimize The Detector Bias Voltage (Gain)
• All un-calibrated AC values associated with (“used”)
source channels (diodes) should be within a factor of
2-4 times the smallest AC value.
• Using a1Hz overall measurement rate, the stdev(phase)should be <
0.15 degrees.
• Uncalibrated modulation ratio should be > 35%
17. Instrument/Sensor Check
Check (Correct) Software Settings
• Open program settings file
• Checksetup calibration block set properties.
• Checksetup sourcedistance settings (must match fiber
connections).
• Checksetup phase reference.
• All the other settings
23. Hold Sensor On Calibration Block
• Sensor must be flat against block.
• Sensor may be held by hand, or with strap but …
Be sure sensor is completely flat against block.
• Only one sensor at a time!
• Cover sensor with dark cloth to block bright room light
•(not shown)
24. If using Flexible Sensor
• Select flat or curved surface to match sample.
• If using the flat surface of the block, remove block plastic cover.
• Use fingers to insure sensor makes contact at all point with the
calibration block.
• Use of the strap to hold the sensor during calibration may allow the
sensor to arch up in the middle, and not be in full contact with the
block. This is particularly true when using the flat surface.
• Optical coupling gel may improve the accuracy of the calibration
25. Use Fingers to Hold Sensor
Against Block. Press in Middle
Careful with
Strap on
Curved
Surface (also
use fingers) No Strap on Flat
26. If using Flexible Sensor
Finally, Run The Calibration Process In the
Software use the “Calibrate for Optical Properties
and Multiple Distances” option
27. If using Flexible Sensor
USE OF “REAL TIME” CALCULATIONS:
-- of best fit slopes, optical properties and
hemoglobin concentration (“Real time” is an option,
it can be done “offline” only.)
28. Optional Real Time Calculations
• Use program settings file suitable for real time multi-distance
calculations. Or setup user calculations using your own math
library (or ISS example math library bml_w2_c4.dll).
• Adjust user calculation parameters as desired.
• Insure weighting for all signals used is not 0 in the
sourcedistance settings dialog.
• Use existing graph examples, or create desired graphs for real
time display
29. With real time calculations we can perform more checks and
examine data quality real time
1. Cross-Calibration Test
• After calibrating, place the sensor on a calibration block with different
absorption and scattering values from the one that was used to calibrate the
channel
• Optimize the detector gain (insure no overvoltage warnings).
• The instrument should now be measuring the properties of the second block
within about +/-15% (for the most optimal configurations +/- 10%)
(Turn Detector Off During Transfer, and Whenever The Sensor Is Not Connecte
to a Subject or a Block)
30. With real time calculations we can perform more checks and
examine data quality real time
2. Check Correlation Coefficient of the
linear regression analysis
33. Optional Real Time Calculations
The following example settings are taken from the example
program settings file
This is an example of using 4 multi-distance
ISS two wavelength sensors with an Imagent in Switch-8 mode.
