title: Towards clinical application: prompt gamma imaging of passively scattered proton fields with a knife-edge slit camera.
abstract: Prompt γ-ray imaging with a knife-edge shaped slit camera provides the possibility of verifying proton beam range in tumor therapy. Dedicated experiments regarding the characterization of the camera system have been performed previously. Now, we aim at implementing the prototype into clinical application of monitoring patient treatments. Focused on this goal of translation into clinical operation, we systematically addressed remaining challenges and questions. We developed a robust energy calibration routine and corresponding quality assurance protocols. Furthermore, with dedicated experiments, we determined the positioning precision of the system to 1.1 mm (2σ). For the first time, we demonstrated the application of the slit camera, which was intentionally developed for pencil beam scanning, to double scattered proton beams. Systematic experiments with increasing complexity were performed. It was possible to visualize proton range shifts of 2-5 mm with the camera system in phantom experiments in passive scattered fields. Moreover, prompt γ-ray profiles for single iso-energy layers were acquired by synchronizing time resolved measurements to the rotation of the range modulator wheel of the treatment system. Thus, a mapping of the acquired profiles to different anatomical regions along the beam path is feasible and additional information on the source of potential range shifts can be obtained. With the work presented here, we show that an application of the slit camera in clinical treatments is possible and of potential benefit.
authors: Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, Bautzner Landstraße 400, 01328 Dresden, Germany.
authors: M
authors: M
authors: Priegnitz
authors: S
authors: S
authors: Barczyk
authors: L
authors: L
authors: Nenoff
authors: C
authors: C
authors: Golnik
authors: I
authors: I
authors: Keitz
authors: T
authors: T
authors: Werner
authors: S
authors: S
authors: Mein
authors: J
authors: J
authors: Smeets
authors: F
authors: F
authors: Vander Stappen
authors: G
authors: G
authors: Janssens
authors: L
authors: L
authors: Hotoiu
authors: F
authors: F
authors: Fiedler
authors: D
authors: D
authors: Prieels
authors: W
authors: W
authors: Enghardt
authors: G
authors: G
authors: Pausch
authors: C
authors: C
authors: Richter
mesh_terms: D015902:Gamma Cameras; D005720:Gamma Rays; D006801:Humans; D019047:Phantoms, Imaging; D061766:Proton Therapy / Q000295:instrumentation* / Q000379:methods*; D011874:Radiometry / Q000295:instrumentation*; D011881:Radiotherapy, Computer-Assisted / Q000295:instrumentation*