MRI robot/MIT 2007 06 27 Meeting
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Participants
- Peter Kazanzides, JHU
- Jack Blevins, Acousticmed
- David Gobbi, Queen's
- Csaba Csoma, JHU
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NaviTrack requirements
- Two types of messages: reliable and fast; both with CRC16 and unique Counter.
- CRC: if a party receives a message with bad CRC, responds with NACK (negative acknowledgment) message to the sender. (What about a NACK with bad CRC? Limit to 10 NAC/sec?)
- Counter: is a 32 bit increasing number, unique for each message. The applications should account for rollover (counter incremented past its size).
- Reliable (command, error event): uses ACK to confirm delivery. Sender keeps re-sending the command (same counter!) until timeout (typically 2 sec) or ACK. (reliable, order guaranteed, blocking, keep all until processed)
- If there's a timeout, it means the communication is lost (hardware error?). The physician is informed and "Abort" or "Retry" choice offered.
- Fast (status, position, images): no attempt to recover lost data. Duplicate or old messages (counter < than the last received) will be discarded, but ACK will be sent anyways. (keep last, best effort)
- Other solution: DDS (ex. Ace/Tao implementation) - DDS links
- Low memory and CPU usage - especially for the embedded computer
- We should deal with the source fork issue. Currently we're 2 step behind: OpenTracker (Austria) ⇒ NaviTrack (Norway - Eigil Samset) ⇒ NaviTrack (NAMIC - Junichi) - use ivs/ivs as username/password. Mail from Junichi:
Currently, the differences between the original and BRP branch are a few additional modules (module for 3D slicer and RT scanner IO) and one modification on GEExciteModule. These are implemented in independent files except GEExciteModule, and we don't need so much work to merge. - Initialize only the used modules. Peter: the initialization part can be copied into the application, avoiding dependency and other problems.
- The "start pushing the robot position" command can be postponed and implemented only if really needed.
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Navigation Software requirements
- Don't initialize / load modules that will not be used during the procedure
- FDA approval
- If we'll store patient data, http://www.clearcanvas.ca/ might be a good start.
- DICOM volumes with the same Frame of Reference (FoR) should be in the same coordinate system, as robot registration is done only in the beginning, and the Z-frame is not visible on the rest of the scans.
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