Owandy Radiology i-max touch 3D, Руководство пользователя

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User Manual
– Quality assurance program
NIMXEN020I
Owandy Radiology SAS 53
6. Press the button ">O<" on the keyboard to run the chin rest automatic positioning.
7. Switch ON the laser and move the phantom in order to align its reference central line to the
sagittal plane; the PVC insertion must be centred inside the internal circle of the support
plate.
8. Press the button ">O<" on the keyboard and and make an exposure at 84kV, 5mA.
9. Right click on the acquired image and select "Export to QC Tool" from the drop-down menu.
8.5.3 Nyquist frequency
Verify that the displayed image looks like the following:
Figure 15
Left click and drag to draw an area as shown in the example picture on the right panel (5 - Figure
11).
Verify that the Nyquist frequency value displayed is greater or equal to 1. Report this value in the
"Nyquist frequency" cell of the QC log book at paragraph 8.5.12.
8.5.4 Contrast to noise ratio
Click on "Next measure" button (6 - Figure 11) to proceed with the "Contrast to noise ratio" test,
which gives information about noise performances.
The image will be loaded automatically; left click to place an area as shown in the example picture
on the right panel (5 - Figure 11).
Two values are displayed:
•
Contrast to Noise Ratio: verify that the displayed value is greater or equal to 4. Report
this value in the "Image noise" cell of the QC log book at paragraph 8.5.12
•
Contrast: verify that the displayed value is greater or equal to 400. Report this value in
the "Low contrast resolution" cell of the QC log book at paragraph 8.5.12.