GE H
EALTHCARE
D
IRECTION
5158821-100, R
EVISION
3
E
X
PLORE
L
OCUS
SP S
ERVICE
G
UIDE
Page 194
24. Calculate the true object position using the following equation, and record in Worksheet:
true object position = (measured pixel size x detector position) ÷ (detector spacing x bin
mode* of the scan)
*bin mode will be either 1, 2 or 4.
Note:
The detector position, spacing, and current Mag_Diff values are found in the Calib. Settings
tab of
Calibration Tools
. OBJ_POS can be found by opening the 2x2wire.protocol file in
Notepad. This file is located in C:\Program Files\GE Medical Systems\eXplore
Utilities\Protocols.
25. Calculate the Mag_Diff using the following equation (Mag_Diff should be approximately 70):
Mag_Diff = true object position - (OBJ_POS in the protocol - current Mag_Diff in registry)
For example:
Mag_Diff = 85.47 - (80 - 65)
Mag_Diff = 70.47
Record values in the Worksheet.
26. Return to the
Calib. Settings
tab.
27. Click
File
and choose
Read Registry Values
from the drop-down menu.
28. Change the Mag_Diff field to the newly calculated magnification difference.
29. Click
File
and choose
Write Registry Values
from the drop-down menu.
When prompted for a password, enter:
EvS8899
7.4.8
Perform Verification Scans (1x1, 2x2, & 4x4 Modes)
The following procedure is used to verify the calibration settings.
Note:
The ambient temperature in the room must be stable to perform this procedure i.e. the room
temperature should not change even by 1 degree during the scanning process.
First perform verification scans for 1x1 mode using the procedure below, then repeat the procedure
in order to perform verification scans for 2x2 and 4x4 modes.
FIND THE IDEAL CENTRE OF ROTATION AT CENTRAL SLICE:
1.
Place the wire phantom in the small specimen tube, secure the phantom with foam, and mount
the tube.
2.
Ensure the filter wheel is set to
4
(or
1
for 4x4 mode).
Summary of Contents for Healthcare eXplore Locus SP
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