ABSTRACT
We investigate the improvement from the use of high-Z CdTe sensors for pre-clinical K-edge imaging with the hybrid pixel detectors XPAD3. We compare XPAD3 chips bump bonded to Si or CdTe sensors in identical experimental conditions. Image performance for narrow energy bin acquisitions and contrast-to-noise ratios of K-edge images are presented and compared. CdTe sensors achieve signal-to-noise ratios at least three times higher than Si sensors within narrow energy bins, thanks to their much higher detection efficiency. Nevertheless Si sensors provide better contrast-to-noise ratios in K-edge imaging when working at equivalent counting statistics, due to their better estimation of the attenuation coefficient of the contrast agent. Results are compared to simulated data in the case of the XPAD3/Si detector. Good agreement is observed when including charge sharing between pixels, which have a strong impact on contrast-to-noise ratios in K-edge images.
Subject(s)
Biosensing Techniques/instrumentation , Cadmium Compounds/chemistry , Image Processing, Computer-Assisted/methods , Phantoms, Imaging , Photons , Silicon/chemistry , Tellurium/chemistry , Tomography, X-Ray Computed/methods , Algorithms , Biosensing Techniques/methods , Humans , Radiographic Image Interpretation, Computer-Assisted/methods , Signal-To-Noise RatioSubject(s)
Carbapenems/pharmacology , Drug Resistance, Multiple , Enterobacteriaceae Infections/enzymology , Providencia/drug effects , Providencia/enzymology , beta-Lactamases/drug effects , Anti-Bacterial Agents/pharmacology , Disease Susceptibility , Ertapenem , Humans , Meropenem , Thienamycins/pharmacology , beta-Lactamases/biosynthesis , beta-Lactams/pharmacologySubject(s)
Anti-Infective Agents/pharmacology , Enterobacter/enzymology , Enterobacteriaceae Infections/microbiology , beta-Lactamases/genetics , Bacterial Proteins/genetics , Base Sequence , Brazil , Enterobacter/genetics , Enterobacter/isolation & purification , Humans , Plasmids/genetics , Sequence Analysis, DNAABSTRACT
GATE (Geant4 Application for Emission Tomography) is a Monte Carlo simulation platform developed by the OpenGATE collaboration since 2001 and first publicly released in 2004. Dedicated to the modelling of planar scintigraphy, single photon emission computed tomography (SPECT) and positron emission tomography (PET) acquisitions, this platform is widely used to assist PET and SPECT research. A recent extension of this platform, released by the OpenGATE collaboration as GATE V6, now also enables modelling of x-ray computed tomography and radiation therapy experiments. This paper presents an overview of the main additions and improvements implemented in GATE since the publication of the initial GATE paper (Jan et al 2004 Phys. Med. Biol. 49 4543-61). This includes new models available in GATE to simulate optical and hadronic processes, novelties in modelling tracer, organ or detector motion, new options for speeding up GATE simulations, examples illustrating the use of GATE V6 in radiotherapy applications and CT simulations, and preliminary results regarding the validation of GATE V6 for radiation therapy applications. Upon completion of extensive validation studies, GATE is expected to become a valuable tool for simulations involving both radiotherapy and imaging.
