1. We have examined the relationship between the attenuation of broadband ultrasound in the os calcis in vitro and its bone mineral density measured by quantitative computed tomography and by physical density. 2. Broadband ultrasound attenuation was found to correlate closely with physical density (r = 0.85, P less than 0.0001), but the correlation was less than that observed between quantitati...

The need to design blast resistant civilian structures has arisen due to aggressor attacks on many civilian structures around the world. Achieving vibration and wave attenuation with locally resonant metamaterials has attracted a great deal of consideration due to their frequency dependent negative effective mass density. In this paper, metaconcrete, a new material with exceptional properties i...

Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid ph...

conclusion we constructed and validated a ct colonography phantom with correct density allowing performance of reproducible experiments. materials and methods we found 15 different phantom designs by literature search and compared their advantages and disadvantages based on their description and images. we tested various materials for density and mechanical properties and constructed a phantom ...

UNLABELLED Present attenuation-correction algorithms in whole-body PET/MRI do not consider variations in lung density, either within or between patients; this may adversely affect accurate quantification. In this work, a technique to incorporate patient-specific lung density information into MRI-based attenuation maps is developed and compared with an approach that assumes uniform lung density....

Background: Multiple beams are generally used with an increased possibility that the beam axis intersects the treatment table. Treatment tabletops are commonly made of carbon fiber due to its high mechanical strength and rigidity, low specific density, extremely light and low radiation beam attenuation properties. Purpose of this paper is investigated the dose changes in the buildup region and ...

Background: This study aims to investigate radiation beam geometry of Cyberknife beam and change in dosimetric characteristics of six megavoltage (6MV) flattening filter free (FFF) beam after passing through high density cadmium free compensator alloy.Material and Methods: In this experimental study, changes in FFF beam dosimetric characteristics after passing through compensator alloy wa...

We show that under a certain non-cancellation condition the attenuated Radon transform uniquely determines piecewise constant attenuation $ and C^2 source density f with jumps over real analytic boundaries possibly having corners. also look at numerical examples in which fails unique reconstruction of multi-bang still appears to be possible although not yet explained by theoretical results.