| Calibration |
| In order to perform the calibration, the
service level must be enable (see chapter 3.3 ” Enabling the service |
| level”). For machine with multiple
FOV the complete calibration of the system consists of two or three |
| different calibrations, one for each Field
Of View (FOV). Each single calibration includes the grid, the |
| mattarellum, the background
and the phantom acquisition and analysis. |
|
| NOTE (Only for machine
with the multiple FOV): |
| • Perform the calibration of the
device following this sequence: Large, Medium and Small FOV. |
| • Terminate the calibration of a
single FOV before proceeding with the next one. |
| • At least 10 Gbyte
of free space are required in order to perform the complete calibration. |
|
| Diaphragm
calibration |
| This procedure is not required in standard
calibration, but only in particular cases or after changing of the |
| image chain. |
| Software configuration |
| The software configuration must be done
the first time we connect a PC to the machine. It stores a flag that |
| permit to the software to use the correct
parameters to calibrate the machine. |
| 1. Press ALT+F10 and insert the password:
336699 |
| 2. In the “General Settings”
window, select the “Configuration” tab |
| 3. Set the “Device Type” parameters
as follow: “CSA Shell” for device labelled as CSA compliant and |
| “Standard” for all others. |
| 4. Select OK to confirm. |
| Diphragm calibration |
| 1. Be sure the plastic frontal panel in
mounted |
| 2. From the main menu select Tools Scanner
tests |
| 3. Move the arm to 45 degrees |
| 4. From the menu select Tools CCD Camera
Pad |
| 5. Select the “Calibr” button. |
| 6. If required select which model of Image
Intensifier is mounted on the device (12” or 9”) |
| 7. Wait the end of the automatic procedure |
| 8. Take note of the values
reported on the final window. Store them in the device’s documentation. |
|
| Grid
calibration |
| 1) Select Scan Grid Acquisition. |
| 2) Select the FOV (large , medium, small)
to be used for calibration. |
| Blank acquisition |
| Before starting the grid acquisition,
the software will require the execution of the blank acquisition. |
| 3) Slide the tabletop all the way out
of the gantry. |
| 4) From the main window of the software
select the “Rx_shot” button. |
| 5) After a few seconds the blank image
will appear. |
| Grid Acquisition |
| Once the blank acquisition has been performed,
the software is ready for the grid acquisition. |
| 6) Mount the calibration Grid on the detector
(see above picture). |
| 7) Verify that the tabletop is still all
the way out of gantry. |
| 8) From the main window of the software
select the “Rx_shot” button. |
| 9) The software will acquire an image
of the grid. |
| 10) Once the image is displayed select
the “Start” button. |
| 11) The acquisition process will start. |
| 12) At the end of the scan the analysis
of the scan will automatically start. |
| 13) After a few minutes the report of
the analysis will appear on the screen. |
| 14) Select File Close. |
| 15) Remove the grid from
the detector. |
|
| Mattarellum
calibration |
| 1) Select the FOV (large , medium, small)
to be used for calibration (must be the same used for the |
| previous grid calibration). |
| Blank acquisition |
| If required by the software perform the
blank acquisition as explained in the following steps. |
| 2) Slide the tabletop all the way out
of the gantry. |
| 3) From the main window of the software
select the “Rx_shot” button. |
| 4) After a few seconds the blank image
will appear. Select the “Stop” button. |
| Mattarellum Acquisition |
| Once the blank acquisition has been performed,
the software is ready for the mattarellum acquisition. |
| 5) Select Scan Mattarellum Acquisition. |
| 6) Insert the mattarellum in the gantry,
with the iron rod in the upper side (see above picture). |
| 7) Verify that the tabletop is still all
the way out of gantry. |
| 8) From the main window of the software
select the “Rx_shot” button. |
| 9) The software will acquire an image
of the mattarellum. |
| 10) Once the image is displayed select
the “Start” button. |
| 11) The acquisition process will start. |
| 12) At the end of the scan the analysis
of the scan will automatically start. |
| 13) After a few minutes the report of
the analysis will appear on the screen. |
| 16) Select File Close. |
| 14) Remove the mattarellum
from the detector. |
|
| Background
acquisition |
| This calibration corrects the dishomogeneity
of the detector. It could be performed also by the user, if rings |
| are reported on axial images. |
| 1) Slide the tabletop all the way out
of the gantry. |
| 2) Select the FOV (large , medium, small)
to be used for calibration (must be the same used for the |
| previous grid and mattarellum calibrations). |
| 3) Select Scan Background Acquisition
(If required by the software perform a Daily Check before |
| proceeding). |
| 4) Once checked the scan area is empty,
select the “Next” button. |
| 5) From the main window of the software
select the “Rx_shot” button. |
| 6) The software will acquire a scout image. |
| 7) Once the image is displayed select
the “Next” button. |
| 8) Select the “Start” button. |
| 9) The background acquisition will start.
This process consists in six consecutive scans that are |
| automatically run by the software. At
the end of the sixth scan the acquired data will be analyzed. |
| 10) Once the analysis process
is terminated select File Close. |
|
| Phantom
QA |
| 1) Activate the service level (see chapter:
3.3 ) |
| 2) Be careful that all corrective factors
are setting to 1 before to start this calibration ( see chapter: 11.6 ). |
| 3) Select the FOV (large, medium, small)
to be used (must be the same used for the previous grid, |
| mattarellum and background calibrations). |
| 4) Run a phantom QA scan as described
in the User Manual. Stop the analisys (press the Cancel button |
| on the reconstruction’s progress
bar). |
| 5) Calculate the corrective factors for
the selected FOV as explained below: |
| Large FOV: a) DSD/DSCR (see 11.6.1 ”
DSD / DSCR calibration”) |
| b) Autocalibration (see 11.6.4 ”
Autocalibration”) |
| c) Z factor (see 11.6.2 ” Z factor
calculation”) |
| Medium and small FOV: a) XY factor (see
11.6.3”X-Y factor calculation”) |
| b) Z factor (see 11.6.2
” Z factor calculation”) |
|
| NOTE (Only for machine
with the multiple FOV): |
| After the phantom analysis is terminated
and all the values are in the ranges, the calibration |
| of the current FOV is complete and it
is possible to proceed with the calibration of the |
| following FOV, starting
from the grid acquisition (see 11.2 Grid calibration). |
|
| Corrective
factors calculation |
| During the manufacturing of the
device, various factors are calculated and stored in the software, in order to |
| be applied to the different FOV
acquisitions. These factors can be viewed in the “General Settings” window |
| under the “Geometric Parameters”
tag (see chapter: 3.4 Opening the “General Settings” window). |
| After the x-ray source or the x-ray
detector has been replaced, these factors may need to be recalculated. |
| Next are the steps
to follow to recalculate these factors. |
|
| DSD
/ DSCR calibration |
| NOTE: The following procedure applies
only to the large FOV. |
| Next are the steps to follow in order
to run the DSD / DSCR calibration. |
| 1. Open the RawData of the last QA phantom
scan, performed using the Large FOV. |
| 2. Select Primary reconstruction ->
DSD / DSCR calibration. |
| 3. Wait for the procedure to terminate. |
| 4. The software will show the two calculated
values and will automatically store them. |
| 5. Perform a new phantom QA scan (using
Large FOV) with complete analysis to verify that the HDE, HDI, |
| VDE and VDI values are
inside the expected ranges. |
|
| Autocalibration |
| The autocalibration process provides an
additional calibration of H FWHM and V FWHM values. |
| 1. Open the Raw Data of the last QA phantom
scan (The scan on the QA phantom must be performed on |
| the same day of the Autocalibration). |
| 2. From the main toolbar select Primary
reconstruction -> Auto Calibration and wait the end of the |
| process. |
| 3. Once the process is finished run a
new phantom analysis on the same scan. |
| 4. Wait the end of the analysis process
and verify that the H FWHM or the V FWHM values are inside the |
| expected ranges. |
| After the analysis is finished is recommended
to perform a few check scan on the QA Phantom RawData in |
| order to have a visual check of the reconstructed
axial images (in term of definition of borders). This control |
| should be done on the edges of the reconstructed
area according to the followin table: |
| FOV Lower* Upper* |
| 12” Between 5 and 6 Between 17.5
and 18.5 |
| 9” Between 2 and 3 Between 13 and
14 |
| 6” 1.5 10 |
| Position of the Check Scan line referred
to the RawData ruler (located on the right side of the scout). |
| NOTE (Multi-FOV devices): |
| After Autocalibration made on 12”
FOV, could be possible that 9” QA Phantom test gives FWHM values out |
| of range or very close to the accepted
limit. Repeat the Autocalibration on 9” FOV. At the end of calibration, |
| perform a QA Phantom scan
and analysis on others FOV to check that new values are good for all fields. |
|
| Calibration
Backup |
| At the end of the calibration a
backup must be done in order to keep a copy of the modified files. Follow next |
| steps to perform the backup process. |
| 1. From the main menu select File
-> Settings Backup. |
| 2. The “Import/Export path
setup” window will appear. Select the “Change Path” button to select the |
| directory where you wish to backup
the files. Use the “Add folder” button to create a new folder |
| inside the selected path. |
| 3. Once the destination path is
ready, select the “Go on” button to start the backup process. |
| 4. At the end a message will appear
informing that the Backup procedure has successfully completed. |
| 5. Burn a CD with the contents of
the directory in which you have just backed up the files. |
| NOTE: The CD containing
the calibration files should be labeled with the serial number of the machine and |
| the date of the calibration and
shall be kept in a safe place. Remember that these data are essential in case |
| of a computer failure
or crash. |
