PET/MR imaging in lung cancer radiotherapy applications
Recently, a new whole-body PET/MRI scanner was developed and installed at St. Joseph’s Healthcare in London, Ontario and remains the only installation in Canada. Two major challenges concerning PET imaging include the need for correcting for loss of photons, called attenuation, due to interactions with patient tissues and the impact of respiratory induced organ/tumour motion during scanning. Corrections for attenuation are currently performed using X-ray CT.
We propose that MRI can also be used to create the attenuation map based on a predefined atlas. We aim to compare 3 atlas design strategies and compare the results with CT-based PET reconstructions. We also propose that respiratory motion can be performed during scanning by retrospectively reconstructing 4D-PET using list mode data and 4D-MRI using ultra-fast 2D MR sequences on multiple slices leading to a 3DPET/MRI scans at multiple phases of the respiratory cycle.