Quality Assurance

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Quality Assurance

Calibration Procedures

Calibration procedures should be performed for quality assurance and in order to evaluate the performance of the MEG system.


CALIBRATION PROCEDURE: PERFORM WHENEVER:
1. Noise / Gain Measurement -there is line frequency noise
2. Head Coil Calibration -head localization results / accuracy is in doubt
3. EEG Gain Calibration -EEG results are uncertain
4. Magnetic Phantom Measurement -the performance of the MEG system is in question



MEG Noise Collection

Noise collection calibration procedures will be performed for quality assurance whenever necessary to evaluate the performance of the MEG system. Noise collection is performed to determine the noise level of each individual channel. Data is collected with no subject and all noise sources are removed from the immediate vicinity of the MEG system.


Procedure for acquiring data:

  • Make sure that the Magnetic Phantom is not connected / setup performing a noise collection.
1. Close the door to the MSR.
2. Click” Acq Manager” (or click on the Terminal Screen and type “Acq” at the prompt line; then go to step# 6.)
a. Click on “Select User”.
3. Select “meglab”.
4. Click on “Launch Acq”.
5. Select the study type: “Noise”.
a. Click on “Ok”.
6. At the Acq Window:
a. Click on “Acquire data”.
7. Create Directory? Select “Ok”.
(If this is the first recording of the day you will need to create a directory)
8. At the Acquisition Monitor Window adjust the scale.
9. Click on Start. There are 10 -10 sec trials.
10. When the collection is done click “Ok” at the “General Information Window”.


Procedure for Plotting the Data:

1. At the "General Information Window" click on "Tools".
2. Click on DataEditor.
3. Click on Set.
a. Select “MEG Left+ZF ZO” channel array.
4. Frequency Spectrum Display icon.
a. Display.
b. Trial.
c. Stack all trials.
5. Change y axis to “5f to 10f”. Hit Enter.
6. List channels that have increased power on the Daily Log.
7. File.
a. Print (Left channel array) to “lwmeglab”.
b. OK.
8. File.
a. Close.
9. Click on Set.
a. Select” MEG Right+ZC ZP” channel array.
10. Frequency Spectrum Display icon.
a. Display.
b. Trial.
c. Stack all trials.
11. List channels that have increased power on log.
12. File.
a. Print (Right channel array).
b. OK.
13. File.
a. Close.
14. At the DataEditor window:
a. Click on File.
b. Exit.
15. File
a. Close Window.
16. At the Acq window:
a. File.
b. Exit.


Head Coil Calibration

EEG Gain Calibration

Magnetic Phantom Measurement

Variance Reporting / Process Improvement