GE Brivo OEC 715 Service Manual page 272

kV mA
4pps 80 1
DAP Accuracy Application Verification:
1. Position C-arm to AP position. Ensure the Monoblock is at bottom and I.I. is at top.
2. Create a new exam named "DAP CHECK".
3. Set Image Intensifier Field Size to MAG2
4. Install BAFT on I.I. Take exposure in Auto Fluoro mode and hold on. Close Iris a little by pressing
the Iris Collimator Close button on control panel until at least two opposite leaves are visible on
left monitor. And then stop exposure. Read the distance on BAFT between any pair of opposite
leaves. Record the value in column "Diameter". The unit shall be mm. Remove BAFT from I.I.
The semi-transparent part of leaves shall be considered. The measurement shall start and
end at the middle of semi-transparent area.
5. Fix Dosimeter detector at II surface. Take an exposure in Auto Fluoro mode, observe and adjust
the Dosimeter detector to the center of I.I. surface. Set up the dosimeter to accumulated dose in
Gy and reset Dosimeter.
6. Set the kVp/mA and exposure mode as the parameters in below table and do measurement in
sequence. For each measurement, record the DAP displayed on left monitor into column "DAP on
monitor before exposure", then take exposure for at least 20 seconds. After exposure stopped,
record the DAP displayed on left monitor in column "DAP on monitor after exposure". Record the
reading dose of Dosimeter in column "Reading Dose". Reset the Dosimeter after each
measurement is done.
7. Calculate and fill DAP estimated in column "DAP estimated".
DAP estimated = DAP on monitor after exposure - DAP on monitor before exposure
Calculate and fill DAP measured in column "DAP measured"
DAP measured = Reading Dose * 0.8285 * Diameter²/ 100000
Calculate and fill Error in column "Error (%)".
Error = (DAP estimated - DAP measured) / DAP measured * 100
8. The errors calculated should meet the requirement according to local regulations (Not more than
30% ):
Dose on the left
monitor= Dose displayed
on left monitor after
exposure- Dose
displayed on left
monitor before exposure
(mGy)
Calibration
Error= (Dose on
the left monitor -
Dose read from
Dose meter )/
Dose read from
Dose meter <30%
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