Our next Imaging and Optical Physics Seminar which will be held on-line via Zoom (see connection details below) from 3 pm on Tuesday, August 25th, 2020. The presenters will be Dr Owen Dillion (University of Sydney) and Dr Andrew Kingston (Australian National University). You can find the information about the presenters and their talks below.
If you don’t have a Zoom client already installed on your computer, phone or tablet, it is advisable to install it before the event – you can just click on any Zoom meeting link below to install the Zoom software at any time. At the start of the webinar, please, mute your microphones (turn it back on only for the periods when you actually want to speak to other participants). Also, please, switch off the video transmission from your cameras in order to save the internet bandwidth.
Here are the connection details that everyone will need to use for this webinar:
Join from a PC, Mac, iPad, iPhone or Android device:
Please click this URL to start or join. https://monash.zoom.us/j/96033269342?pwd=dERsL2pGdHJEcSs2VlgyNjdaK2JPQT09
Or, go to https://monash.zoom.us/join and enter meeting ID: 960 3326 9342 and password: 96105939
Dr Owen Dillon (ACRF Image X Institute, University of Sydney)
Title: Faster, Safer, Clearer X-Ray Imaging through Respiratory Motion Compensation
Abstract: Effective Radiation Therapy of lung cancer requires the treatment beam be carefully guided to cancerous tissue while sparing healthy tissue. The current standard pre-treatment scan is 4D Cone Beam Computed Tomography (CBCT) in which 1,320 2D x-ray images are acquired over 4 minutes, retrospectively sorted by respiratory phase, and used to reconstruct each 3D frame of the 4D image used for guiding the beam. This contributes a substantial amount of time and dose to each 15-30 minute treatment performed over 20-40 days.
In this talk I will present results from a first-in-human clinical trial, in which we produce clearer 4D images from just 200 2D x-ray images acquired over 1-2 minutes. We achieve this through 2 motion compensation technologies developed at the ACRF Image X Institute. The first is Respiratory Motion Guided (RMG) acquisition, where the imaging hardware adapts in real time to patient respiration, to ensure each 2D image contains the most useful information for 4D reconstruction. The second is Motion Compensated reconstruction, in which a motion model is estimated as part of the reconstruction, allowing each 2D image to contribute to each 3D frame of the 4D reconstruction.
Dr Andrew Kingston (Australian National University)
Title: Exploring the potential for quantitative x-ray tomography in the lab
Abstract: I will first briefly introduce the lab-based x-ray microtomography group at ANU and its capabilities. To date we have focused on imaging high-resolution 3D morphology, i.e., shape/structure, for measurement/modelling of mechanical and transport properties of samples. Over the last few years we have started exploring the potential for quantitative imaging of 3D volumes using the Alvarez-Macovski model for x-ray attenuation. This typically requires imaging the sample with two different broadband X-ray spectra. This "dual-energy" imaging is costly in time and computation resources, and the high-energy scan contributes little information for many samples. I will present two methods we have developed that have the potential for quantitative 3D imaging using only a single broadband spectrum. The first relies on assumptions about material properties and the second uses the mean and variance of measured intensity data.