The ‘Simultaneous Maximum-Likelihood Attenuation Correction Factors’ (sMLACF) algorithm presented here, is an iterative algorithm to calculate the maximum-likelihood (ML) estimate of the activity λ and the attenuation correction factors a in time-of-flight (TOF) positron emission tomography (PET), and this from emission data only. sMLACF is derived using the expectation-maximization (EM) princi...

Groundwater contamination by chlorinated hydrocarbons is a worldwide problem that poses important challenges in remediation processes. In Italy, the Legislative Decree 152/06 defines water quality limits to be obtained during cleanup process. situ bioremediation techniques are becoming increasingly due their affordability and, under right conditions, because they can more effective than convent...

Introduction: The main goal of SPECT imaging is to determine activity distribution inside the organs of the body. However, due to photon attenuation, it is almost impossible to do a quantitative study. In this paper, we suggest a mathematical relationship between activity distribution and its corresponding projections using a transfer matrix. Monte Carlo simulation was used to find a precise tr...

Introduction: Photon attenuation in tissues is the primary physical degrading factor limiting both visual qualitative interpretation and quantitative analysis capabilities of reconstructed Single Photon Emission Computed Tomography (SPECT) images. The aim of present study was to investigate the effect of attenuation correction on the detection of activation foci following statistical analysis w...

Introduction: To date, gold nanoparticles (GNPs) have been demonstrated to have great potential as contrast agent for CT imaging and therapeutics. This study was designed to evaluate any effect on X-ray attenuation that might result from using GNPs with a variety of size, surface chemistries and shapes.   Materials and Methods: Spherical GNPs and gold nanorod...

development of ultrasound technique has not been progressing for evaluating the internal quality of fruits as fast as that of processed foods. in this research for quality assessment of pear fruit (shah miveh variety) an ultrasonic measurement system was constructed to transmit and receive the ultrasonic waves. the apparatus included a pulser-receiver, a pair of 75 khz ultrasonic transducers wi...

Statistical comparison of two remediation methods: Remedial nutrient solution and enhanced natural attenuation were analyzed in terms TPH different soil samples collected from Khana Local Government Area Rivers State, Nigeria at locations placed inside sample bottles labelled A to D replicated into two, one for each the above treatment technique. The was determined using GC analyzer after solve...

Citrine is a transparent gemstone, yellow microcrystalline quartz variety. Natural citrine is very rare and will actually lose its color upon heating to more than 200°C, and the yellow color will occur again when the crystal is irradiated with Xor gamma-rays, indicating that attenuation parameters is important to enhancements by irradiation. In this work, the mass attenuation coefficients of ci...

X-ray microcomputed tomography (μCT) is an invaluable tool for visualizing plant root systems within their natural soil environment noninvasively. However, variations in the x-ray attenuation values of root material and the overlap in attenuation values between roots and soil caused by water and organic materials represent major challenges to data recovery. We report the development of automati...