ESTRO 2023 - Abstract Book

S1584

Digital Posters

ESTRO 2023

Conclusion The novel Varian HyperSight CBCT system demonstrated high performance for all image quality tests performed with Catphan. Image quality metrics were on par with those measured on the Siemens Somatom Edge CT scanner and substantially outperformed current CBCT imaging systems on Varian TrueBeam and Halcyon version 2.0.

PO-1847 Longitudinal stability in the dielectric wall accelerator through time-varying accelerating fields

C. Lund 1 , P.M. Jung 2 , M.J. Maher 1 , J. Bancheri 1 , T. Planche 2 , R. Baartman 2 , J. Seuntjens 3

1 McGill University, Medical Physics Unit, McGill University Health Centre, Montreal, Canada; 2 TRIUMF, Beam Physics, Vancouver, Canada; 3 University of Toronto, Princess Margaret Cancer Centre, Radiation Medicine Program, University Health Network, Toronto, Canada Purpose or Objective As part of the development of a dielectric wall accelerator (DWA)-based compact proton therapy (PT) device, this work aims to demonstrate longitudinal particle stability in a DWA for the first time. This is important for Bragg peak sharpness, maximum dose rate, and other PT dose characteristics. In particular, we test whether linear time variations in the accelerating fields can produce a corrective force gradient about the reference trajectory during acceleration. Materials and Methods The particle-in-cell code Warp was used to track a 1 µ A stream of 25 keV protons through a novel numerical DWA model. This model consists of: (i) a multipole expansion describing the spatial distribution of each field, (ii) a time profile (1 ns FWHM) describing the ramp-up, linear variation Γ ', and ramp-down of each field, and (iii) a set of differential equations used to describe the reference trajectory, i.e. the dynamics of an idealized fictitious particle, and to coordinate the relative timing of each field. See Figure 1. The phase space distributions and their second moments were tracked through a 15 cm (150 modules), 10 MeV/m DWA segment (representative of a pre-accelerator) and compared for Γ ' ∈ [-2,2] MeV/m/ns.