Speaker
Description
The currently established imaging modality used for treatment planning in ion therapy is x-ray computed tomography (CT). Due to the non-bijective relation between the photon attenuation coefficient, reconstructed with x-ray CT, and the relative stopping power (RSP) required for ion therapy treatment planning, RSP errors of about 3% may occur [1]. The use of ion CT promises to yield improved RSP estimation as input to particle therapy treatment planning [2], at a low imaging dose. Recently, proton CT (pCT) has been shown to yield RSP accuracy on par with state-of-the-art x-ray dual energy CT [3]. Several pCT prototype systems have been built or are currently in the design face [4-7].
In this talk, the current status of pCT will be first reviewed. A large number of studies has been published by different groups presenting different approaches for building a pCT scanner. For many of these systems, the RSP accuracy and the spatial resolution achievable with different pCT scanners has been quantified and compared to the theoretical limits of pCT [3, 6, 7, 8]. In addition, work has been done in investigating how the performance of these systems translates to particle therapy treatment planning/dose calculation [9,10]. As pCT systems have not yet matured to commercial products, a lot of effort is still invested into optimizing their image quality. A few of the artifact reduction methods applied to pCT will be also presented [11,12]. Finally, motivated by the envisaged use of pCT beyond simply treatment planning, to its application to image guidance, the concept of fluence modulation as a means for extremely low dose clinical imaging modality will be outlined [13].
REFERENCES
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[13] J. Dickmann, F. Kamp, M. Hillbrand, S. Corradini, C. Belka, R.W. Schulte, K. Parodi, G. Dedes, G. Landry. Phys Med Biol. 2021 Mar 2;66(6):064001.