OMPI Seminar: Ming Lui and Pat Saull

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Thursday, February 16, 2017

Time: 3:30 - 5:00 pm. Refreshments start at 3:15 pm.

Location: Carleton University, 1125 Colonel By Drive, Herzberg Building, Room 4351.


1) Student speaker: "Accuracy of the CyberKnife Synchrony respiratory tracking system for liver cancer"

By Ming Liu, PhD student, Carleton University

Supervisors: Drs. Eric Vandervoort and Joanna Cygler.

Abstract: Organ motion management during radiotherapy treatment is the biggest challenge for accurate dose delivery to the tumor. The CyberKnife® Robotic Radiosurgery System tracks real-time respiratory motion and automatically corrects for changes in the tumor position. The Synchrony respiratory motion compensation system used by CyberKnife estimates tumor motion based on the positions of internally implanted fiducials and external motion from LED markers located on the exterior of the patient. For each treatment, the CyberKnife system generates log-files that include estimates of its own tracking accuracy, based on the difference between predicted and internal fiducial position measurements acquired every 1 to 2 minutes. Today, I will present a retrospective analysis of the log-files for 40 liver patients treated on the CyberKnife at TOHCC. I will also show a software tool I created that allows for off-line analysis of patient breathing traces recorded in treatment log-files.


2) Member speaker: "Compton gamma imaging"

By Pat Saull, PhD, National Research Council Canada

Abstract: I present recent results on the development of Compton gamma imagers for safety and security, an effort lead by NRC in collaboration with researchers and end users from NRCan, DRDC, CBSA, the RCMP, and DND. Starting off with EGSnrc simulations of a pinhole camera imaging gamma rays of varying energy, I briefly discuss the coded-aperture approach before showing how well the Compton method works using experimental data from a 262-channel, all-scintillator, lab-based Compton imager. The design and fabrication of a 40-channel portable imager read out entirely with silicon photomultipliers is reviewed and the results obtained with it during recent field exercises shown. Our first pass at a commercial imager is introduced. Finally, because Compton imagers are also spectrometers, a method is outlined for calibrating an imager in terms of air-kerma rate at different energies using calibrated liquid sources combined with EGSnrc simulations. There may be a movie, but maybe not.


3) Social Event: Message from the graduate student representative Martin Martinov:

Due to the relatively hot temperatures of this winter, skating down the canal does not seem as viable an option this year as it was in previous years.  Worry not though, as you can drink your warm winter woes away at Patty's Pub, located at 1186 Bank Street.  It is only a 5 minute drive,

15 minute bus ride or even a 30 minute walk (if you are so inclined) from Carleton.  It is a great opportunity to socialize with other OMPI members whom you normally see only once a month.  I hope to see you there!