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...

Fully three-dimensional (3D) positron emission tomography (PET) can achieve high sensitivity of coincidence events, but the absence of inter-slice septa inevitably leads to increased scattered events. The scattered events can represent as much as 50% of the total detected events. In this research, we proposed a scatter correction method for 3D PET based on beam stoppers and dual-energy window a...

this paper reports on the use of artificial neural networks (ann) and partial least squareregression (pls) combined with nir spectroscopy (900-1700 nm) to design calibration models for thedetermination of sugar content in sugar beet. in this study a total of 80 samples were used as the calibration set,whereas 40 samples were used for prediction. three pre-processing methods, including multiplic...

introduction spect projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. backscatter constitutes a major part of the scatter contamination in lower energy windows. the current study is an evaluation of the effect of backscatter material on fwhm and image quality investigated by monte carlo simulation. materials and methods simind program...

The transmission dependent convolution subtraction method which is one of the methods for scatter correction of SPECT was applied to the assessment of CBF using SPECT and I-123-IMP. The effects of scatter correction on regional distribution of CBF were evaluated on a pixel by pixel basis by means of an anatomic standardization technique. SPECT scan was performed on six healthy men. Image recons...

Introduction: The key characteristics of positron emission tomography (PET) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. Therefore, accurate quantification is important. However, it can be sensitive to several physical factors. The aim of this investigation is the assessment of the e...

One of the most important challenges for practical face recognition systems is to make recognition more reliable under uncontrolled lighting conditions. We tackle this by using novel illumination-insensitive preprocessing method. The proposed face recognition system consists of a gamma correction, a preprocessing stage, a hybrid Fourier-based facial feature extraction, and Principal Component L...

UNLABELLED (201)Tl-Chloride ((201)Tl) is a myocardial perfusion SPECT agent with excellent biochemical properties commonly used for assessing tissue viability. However, cardiac (201)Tl SPECT images are severely degraded by photons scattered in the thorax. Accurate correction for this scatter is complicated by the nonuniform density and varied sizes of thoraxes, by the additional attenuation and...