Studies of different ion imaging modalities at MedAustron
Speaker: Stefanie Kaser
Abstract
MedAustron is an ion therapy treatment center located in Wiener Neustadt, 50 km south of Vienna. As ion imaging has the potential to improve the treatment planning process in the future, an ion CT demonstrator system was installed at the facility by the Institute of High Energy Physics of the Austrian Academy of Sciences and the TU Wien. It consisted of four double-sided silicon strip detectors (DSSDs) for single particle tracking and a range telescope to determine the particles' energy loss (WET). Although the size of the DSSDs (5.12 x 2.56 cm2) limited the phantom size to small objects, the demonstrator allowed to investigate the basic principles and challenges of ion imaging, which can be used in the development process towards a clinical system in the future. Besides energy-loss iCT scans, the implemented iCT demonstrator also allowed to study other ion imaging modalities, such as scattering radiography and beam attenuation radiography. Measurements were performed at various beam energies using a stair-shaped aluminium phantom with a side length of 1 cm. While radiographic ion images rely on the binning procedure, a full iCT scan further requires a sophisticated reconstruction algorithm. Therefore, the open-source and CUDA-based x-ray CT reconstruction toolbox TIGRE was extended with an existing pre-reconstruction binning method, which allows using the already implemented algorithms also for ion imaging. To investigate phantoms of larger size than the demonstrator allowed, Monte Carlo simulations were used to generate reconstruction data. Images obtained from data measured with the iCT demonstrator as well as image reconstructions from Monte Carlo data will be presented.
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