7T general info & troubleshooting

Overview page for 7T related information

Table operation

'Important: move table to fully outer position before resetting or undocking

Undocking/docking the table

Warning: not following the right undocking procedure will damage the equipment!

• When scanning with dualTx: Disconnect cables and remove interface boxes
• Pull table pins up (ensure they stay up)
• Undock

Resetting table / manual operation

In case the table operation does not respond:

• Try stop/reset multiple times. Wait.
• 3-finger reset (takes 2 minutes). Wait. Repeated if needed.
• Undock table (follow procedure above). Wait 1 minute before docking.
• Manual undocking: switch at lower right hand of the magnet:
  • up: undock - careful: connector will come out of docking station!
  • center: ready to dock
  • down: dock(?)
• CDAS reset (see elsewhere on this wiki)

If table beeps, bed position is lost, probably caused by not resetting not in outer bed position. Press Stop. Pull bed out manually. Follow reset procedure above.

If all fails, the table can be pushed in manually:

• bed must be docked and connected.
• go to manual mode by pressing Stop: red lights on bore will turn on. Push the small safety handle/lever at the front bottom of the bed and push the bed in. Do this slowly!

The bed is in the iso-center when aligned which the edge of the bore / 2nd pencil line on the bed. In all cases, call support, and/or Anton/Cor from Philips. Explain what was scanned/happened beforehand and report date/time.

R3

stop/start all processes (NB including data transfer!)

• permproc stop|start all stop|start all processes
• c:\nmr\gyroscan\commands\activate_configuration.pl. type y, Enter.
• start_stop_procs.pl stop also stops background processes. Needed in case of hardware reset in service room.

Communication with PRIDE (e.g. for image-based shimming):

• PrideXS_XML. In case of error Access denied, no SW key pressed, kill process pridexsproc_win_cs.exe in Task Manager.

Export raw data:

• System --> Advanced tools --> Delayed reconstruction. 'Select exam', type number of exam. Click 'Prev Scans'. 'Type 2'. Select 'Raw Export'. Now type the number of your series. Click Proceed. Type a number to save your series under. (Choose a different one for each series to avoid overwriting earlier ones). Type Enter/Proceed a few times. Now the scan is added to the scan list. You can add more series to reconstruct or continue, by clicking Start Scan and click Proceed.
• When finished click 'Exit' to release this scan to the scanner database again. Your data will appear under G:\Temp (sort by date to find it) as raw_00XX.list / raw_00XX.data where XX is the number you gave it earlier.
• Note that this doesn't work under the MISS patch (version oct 2015). You can, however, export raw MISS data by removing the patch and then following the steps described above.
• Alternatively use gt pack 'n go utility. This requires ReconFrame (which we don't have yet) and licensed matlab software to reconstruct raw data. Note that this tool does not export the same raw data format.

Location shim parameters:

• E:\Export\PRIDE\shimtool\linear_shim.txt

Manually selecting coil elements:

• Control Parameter Editor - Scan (approx 1/3, 6x clicking):
• User def. channel selection - yes
• at initial, Xmit Coil selection. choose 0.
• Dual coil - No. (2e surface coil off, independent selection per surface coil not possible)

Direct protocol comparison (useful while we still run on R3)

• Export exam card with the protocols you want to compare.
• Do this:

Delayed Reconstruction

• User def element selection: yes
• selecteer elementen: waarde 1

Saving and loading configuration file

• MRService inloggen
• MR Applications - Service tools - Export configuration
• Enter (na afsluiten software)
• Choose 1 for internal disk to write to (I - make new folder (no spaces))
• As directory I fills up quickly, it's probably a good idea to replace the configuration directory that's already there.

• To reset configuration to previous : MR Applications - Service tools - Import configurations

Changed system settings

Changed default settings

• Control parameter Reconstruction: Noise clip factor 1,2,3: 0.001. Avoids noise clipping of phase to -pi in case the SNR is too low.
• Go to System Tuning, Tuned Hardware. HIGH RF aux drive scale: 0.7915 en 0.8572. Dit was door Service afgeregeld op 0.8542 en 0.9252. Deze waardes zijn sqrt(15%) verlaagd, omdat de gelogde power afwijkt van wat op de PMU (in technische ruimte) getoond wordt. Dit is af te lezen terwijl de scanner loopt. Setting stored door Maarten Versluis (2016-03-02), MV: updated calibrated DS

Patches

• Increased maximum average power to 20:
  • max_avg_pow: 20 in mpgcoil_volume_tr_mtx.i and mpgcoil_volume_tr.i, add file to patch folder to apply. Check Coil parameters en logfile (zoek op PMU), dat niet de default waarde van 15 gebruikt wordt!

Scanning sequences

• B1 mode: 17 uT (dus niet op default). 20 uT wordt bijna nooit gehaald in vrijwilligers (zie data monitoring), de fliphoek moet na PO groter dan 80 graden zijn!
• Preparation phases: full (dus niet auto). Bij auto wordt de pickup-coil drive scale gekozen, als de power optimization failed, wordt dit de default waarde plus safety margin = 0.19 + 25% = 0.23. Dit resulteert in half vermogen, dus halve B1!

Power off and power on sequence(s)

CDAS

• Reset CDAS: turn off green switch. Wait 5 seconds.
• Turn red switch.
• Unplug sense-cable (on top, labeled with red arrow, this will reset/enable bore light). Wait 5 seconds.
• Turn on in reverse order: red switch and green switch.
• Wait for bed-lights (top) to turn green. Now plug in the sense-cable (red arrow). This controls bore light.
• At bed console, set light to 50%.

Main System

• Power off sequence: 1. scan computer. 2. CDAS. 3 Power gradient (right) and System (left), see Leiden document (original in scstaff)
• Power on sequence: in reverse order

Compressors

Procedure testing/resetting compressors Helium pump: 2 small cubic devices in the far right corner. The green light on the left device should be flashing. Check messages on small LED-displays: scroll with arrow up/down buttons. Should all be OK, not ERR. Temperature of tubes should be below room temperature (i.e. cold). To reset: press OFF. You should hear it switching off. Wait, and press ON, again hearing it switching on. To hard reset: Press OFF. Wait. Turn small black switch from I to O. Wait. Turn back to I. Wait. Important: press ON to turn the compressor back on.

(Common) errors, malfunctions and fixes

Scan aborted after error

• B1 cannot be reached. Lower B1 (in Contrast tab) from Default to 17,15, or 10.
• Coil parameters are not set correctly. Perhaps not added to a patch? Check settings above.

Scan aborts after 30 seconds

Average power is too high. Probably a scan with high SAR. Check that max average power is increased from 15 to 20 (see above).

No trigger

• Check if sync box on console pc has power (right LED green)
• Unplug/replug power.

• table
• coldhead compressors
• gradient amplifiers

No power in bed, won't dock, no 'air puffs'

• Probably no air pressure
• Check meters in cabinet at the back of CDAS (remove panel using imbus size 5)
• Pressure meters should look approx. like this: [picture to be uploaded]

No physiologic signals being logged

• Check if all sensors are plugged in, at least ECG!
• Check if ECG sensor has (working) battery
• If this is OK, switch CDAS off/on (after switching off host!)

Defect in shim gradients

Irregular 'cracking noise' in scanner room. Originates from shim rack.

Not all scanner functions available

Might have an error in shim gradients. For reset:

• Enter on the computer: "permproc stop scanner"
• Turn off the 3 switches (at the bottom) of the shim gradients in the technical room. Turn off in following order: Middle, left, right and wait a couple of seconds
• Turn on the 3 switches in reversed order
• Enter on the computer: "permproc start scanner"

Coil-specific tips 'n tricks

Microcoils MR Coils (surface coils)

• acquire B0 not with commonly used pickup coil elements but instead the surface coil elements. The Shimtool should apply mask to area with signal only
• connect the two surface coils mixed on the two interface boxes, not one separately on each box

Hardware

Patient ventilation system

Box hanging the CDAS rack. Turn off by unplugging 220V cable.

Defect in shim gradients

Irregular 'cracking noise' in scanner room. Originates from shim rack.

Contact information

Philips contacts (?)

Cor Romeijn: 06 22489509 Anton Heijmans: 06 22491918 Maarten Versluis: 06 11386561 Philips service: 040 7001210

AMC Contacts

During office hours, contact front office on phone number 88, option 2 Regelkamer: 62900 (outside office hours) Ed de Klerk: 06-30005770 Tom Emke: 020-5662305, 06-22452389 Roelofsen: 68103