Breakthrough In Cancer Therapy Using Radiation - Linac-MR System Operational With MR Imaging During 6 MV Irradiation

Main Category: MRI / PET / Ultrasound
Also Included In: Cancer / Oncology;  Radiology / Nuclear Medicine
Article Date: 23 Dec 2008 - 1:00 PDT

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Fallone from the Cross Cancer Institute (CCI) , Alberta Cancer Board of the Alberta Health Services (Edmonton, AB) reports that CCI medical physicists have produced the first image from a linac-MR hybrid system on December 10, 2008. The MR images during 6 MV irradiation do not show significant distortions and are very similar to those obtained prior to irradiation. There is a small difference in signal-to-noise between images. MR image is obtained during the irradiation from a 6 MV linac. The linac-MR system that has been built consists of a 6 MV linac mounted on the open end of a biplanar 0.2 T MRI. Both the linac and the MR system are mounted on a single gantry that would rotate around the patient. The opening between the planes of the biplanar MR system is about 27 cm, large enough for a head. The design of the system avoids mutual magnetic and RF interferences allowing for a real-time MR imaging irradiated by the linac.

The imaging experiment offers a proof-of-concept that our linac-MR system offers real-time MR imaging during irradiation by the 6 MV linac. Image Optimization and testing is being performed to improve performance. A major scientific grant application has been submitted by our group to the Canadian Foundation for Innovation and the Alberta Science and Research Investments Program to develop a whole body system for clinical research trials. Progress of our activities can be tracked by browsing our website: linac-MR.ca.

Axial slices were obtained with a raw gradient echo sequence, flip angle =90 o, TE=14.0 ms, TR=300 ms, Bandwidth = 10000 Hz, matrix size=128x128, No-Averages=4, slice thickness=7 mm, FOV=100x100. The phantom consists of an acrylic rectangular cube 15.95 x 15.95 x 25.4 mm (0.628 x 0.628 x 1.0 inch) with holes of diameter 2.52 mm, 3.45 mm and 4.78 mm (0.099 inch, 0.136 inch, 0.188 inch) drilled parallel to the length of the rectangular cube. The cube is immersed in a 10 mM solution of CuSO4 within a plastic container 22.5 mm inner diameter.

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Source
B Gino Fallone,
Director, Dept of Medical Physics
Cross Cancer Institute
Professor and Director, Medical Physics Division, Dept. of Oncology, U of Alberta
11560 University Ave,
Edmonton, AB, Canada T6G 1Z2
http://www.linac-MR.ca
http://www.mp.med.ualberta.ca