First experimental verification of prompt gamma imaging with carbon ion irradiation
Aicha Bourkadi Idrissi, G. Borghi, Anita Caracciolo, Christian Riboldi, Marco Carminati, Marco Donetti, Marco Pullia, Simone Savazzi, F. Camera, C. Fiorini
Abstract
Prompt Gamma Imaging (PGI) is a promising technique for range verification in Particle Therapy. This technique was already tested in clinical environment with a knife-edge-collimator camera for proton treatments but remains relatively unexplored for Carbon Ion Radiation Therapy (CIRT). Previous FLUKA simulations suggested that PG profile shifts could be detected in CIRT with a precision of $$\sim$$ 4 mm ( $$2 \sigma$$ ) for a particle statistic equal to $$5 \cdot 10^{7}$$ C-ions using a 10 × 10 cm2 camera. An experimental campaign was carried out at CNAO (Pavia, Italy) to verify these results, using a knife-edge-collimator camera prototype based on a 5 × 5 cm2 pixelated LYSO crystal. PG profiles were measured irradiating a plastic phantom with a C-ion pencil beam at clinical energies and intensities, also moving the detector to extend the FOV to 13 × 5 cm2. The prototype detected Bragg-peak shifts with $$\sim$$ 4 mm precision for a statistic of $$\sim 4 \cdot 10^{8}$$ C-ions ( $$3 \cdot 10^{8}$$ for the extended FOV), slightly larger than expected. Nevertheless, the detector demonstrated significant potential for verifying the precision in dose delivery following a treatment fraction, which remains fundamental in the clinical environment. For the first time to our knowledge, range verification based on PGI was applied to a C-ion beam at clinical energy and intensities.