PURPOSE To evaluate the impact of common radiation-shielding strategies, used alone and in combination, on scattered dose to the fluoroscopy operator's eye. MATERIALS AND METHODS With an operator phantom positioned at the groin, upper abdomen, and neck, posteroanterior low-dose fluoroscopy was performed at the phantom patient's upper abdomen. Operator lens radiation dose rate was recorded wit...

We propose a pinhole-based fluorescent x-ray computed tomography (p-FXCT) system with a 2-D detector and volumetric beam that can suppress the quality deterioration caused by scatter components. In the corresponding p-FXCT technique, projections are acquired at individual incident energies just above and below the K-edge of the imaged trace element; then, reconstruction is performed based on th...

Polycapillary x-ray optics provide an innovative new way to control x-ray beams. Placing these optics after the object to be imaged provides very efficient rejection of Compton scatter, while allowing image magnification without loss of resolution, image demagnification, or image shaping to match with digital detectors. An extensive study of the effects of surface and profile defects have great...

The purpose of this study is to evaluate the performance of an antiscatter grid and its potential benefit on image quality for a full-field digital mammography (FFDM) detector geometry at energies typical for temporal subtraction contrast-enhanced (CE) breast imaging. The signal intensities from primary, scatter, and glare were quantified in images acquired with an a-Si/CsI(T1) FFDM detector us...

Accuracy and limitation of energy-window based scatter correction techniques have been evaluated for myocardial 201Tl SPECT by means of Monte Carlo simulation. In particular, projection view-dependency of energy distribution of the scattered photons was evaluated. Two geometrical configurations were simulated: namely a homogeneous cylindrical radioactivity located asymmetrically in a homogeneou...

In therapy imaging there is a need to optimize imaging protocols and different correction methods for e.g. photon attenuation, contribution from scatter and other physicsrelated effects that limits the possibility to achieve accurate quantitative results. Physical phantom studies are important but lack flexibility and are often difficult to make patient realistic. A complement is to simulate th...

The qualitative and quantitative accuracy of SPECT images is degraded by physical factors of attenuation, Compton scatter and spatially varying collimator geometric response. This paper presents a 3D ray-tracing technique for modelling attenuation, scatter and geometric response for SPECT imaging in an inhomogeneous attenuating medium. The model is incorporated into a three-dimensional projecto...

Introduction: The head scatter factor (Sc) is important to measurements radiation beam and beam modeling of treatment planning systems used for advanced radiation therapy techniques. This study aimed to investigate the design of a mini-phantom to measurement variations in collimator Sc in the presence of shielding blocks for shaping the beam using different field sizes. <str...

A prototype time-of-flight (TOF) PET scanner based on cerium-doped lanthanum bromide [LaBr(3) (5% Ce)] has been developed. LaBr(3) has a high light output, excellent energy resolution and fast timing properties that have been predicted to lead to good image quality. Intrinsic performance measurements of spatial resolution, sensitivity and scatter fraction demonstrate good conventional PET perfo...

The study was to explore the feasibility of improving cone-beam CT (CBCT) number (corresponding to the Hounsfield units in computed tomography) consistency using a scatter-correction algorithm, with the aim of using CBCT images for treatment planning with density correction. A scatter correction algorithm was applied to a Varian OBI CBCT and an Elekta XVI CBCT, and was evaluated for improving C...