Discovery QDR Series Technical Manual
3-67
Note: Enter this information into the Radiation Measurement Report (see
example on page 3-70).
3.5.15 Measure X-Ray Scatter From Phantom
A radiation scatter measurement must be performed at the time of installation. You must
use a survey-type radiation meter (Victoreen 450P or equivalent).
Perform the following:
1. Center the table and C-arm
2. Place the spine phantom in the center of the table and align using the laser.
3. Start an AP Spine scan.
4. Using the
<Esc>
key, stop the scan when it is between the two middle vertebrae.
5. Start the X-Ray Survey Utility by selecting Utilities|Service Utilities|X-Ray
Survey (see “X-Ray Survey” on page 9-1 for information on the utility).
6. Using the survey meter, measure the scatter radiation at a distance of 2 meters
from the phantom on a horizontal plane all around the unit. Move the meter
slowly (refer to the Victoreen response table on page 3-59).
Note: If you cannot measure the scatter radiation at a distance of 2 meters
because of space restrictions, you can measure at 1 meter and divide the
result by 4. This reading must be less than 10
µ
Gy/h (1.0mrad/h) at 2
meters (approx. 80 in.) in array AP scan mode.
7. Record the highest reading in the service report and then turn off X-rays by click-
ing on X-ray (F2).
Note: Enter this information into the Radiation Measurement Report (see example on
page 3-70).
3.5.16 Perform QC
Once the machine has been fully assembled and calibrated, at least one QC scan should be
performed.
•
Perform the daily QC procedure and enter the scan into the QC database.
3.5.17 Run Reproducibility Test
Reproducibility is the ability of the scanner unit to perform consecutive scans while
keeping the amount of radiation for each scan consistent. Instrument reproducibility is
tested by running 10 consecutive scans of the spine phantom shipped with the unit. You
must then plot the results of the High Air and Low Air measurements for these scans and
WARNING:
X-rays are generated during this procedure. Keep hands, head and other body parts out
of beam.
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