Progress towards a semiconductor Compton camera for prompt gamma imaging during proton beam therapy for range and dose verification

Abstract

The main objective of this work is to test a new semiconductor Compton camera for prompt gamma imaging. Our device is composed of three active layers: a Si(Li) detector as a scatterer and two high purity Germanium detectors as absorbers of high-energy gamma rays. We performed Monte Carlo simulations using the Geant4 toolkit to characterise the expected gamma field during proton beam therapy and have made experimental measurements of the gamma spectrum with a 60 MeV passive scattering beam irradiating a phantom. In this proceeding, we describe the status of the Compton camera and present the first preliminary measurements with radioactive sources and their corresponding reconstructed images. KEYWORDS: Compton camera; semiconductor detector; prompt gamma; Monte Carlo; Geant4; 2.1 Simulations of gamma spectrum 2 2.2 Experimental measurements of gamma spectrum 2 2.3 Spatial distribution of gamma emission 4 3. Semiconductor Compton camera 4 3.1 Compton camera principle of operation for 3D imaging 4 3.2 ProSPECTus-based Compton camera for prompt gamma imaging 5 3.3 Image reconstruction using Stochastic Origin Ensemble 6 4. Conclusion 8

Crosstalk Reduction Using a Dual Energy Window Scatter Correction in Compton Imaging

“…Compton imaging is applied to range estimation in particle therapy [37][38][39] and to environmental measurements [40][41][42]. In these applications, the scattered noise component is larger than that in nuclear medicine imaging, because the number of high-energy radiations significantly exceeds that of signals radiations.…”

Single-layer Compton camera based on a 1 mm thick pixelated CDTE detectors

“…Compton camera is a novel gamma camera concept that relies on Compton scattering kinematics for image reconstruction instead of physical collimation as in a conventional gamma camera system [1,2,3]. This feature gives the Compton cameras greater detection efficiency and a wider field of view.…”

Prompt-gamma emission in GEANT4 revisited and confronted with experiment

“…Monte-Carlo simulations play a crucial role in the design and optimization phase o f detection setups, including those dedicated for prompt-gamma imaging (PG I) [8][9][10][11][12]. Not only the detector response is modelled this way, but also the characteristics o f gamma quanta induced in the irradiated object by a proton beam, which depend on the description o f the underlying processes in a given implementation o f a Monte-Carlo engine.…”