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...

introduction: the photoelectric attenuation coefficient of substances is known to depend upon the energy e of the photon and the effective atomic number of substances (zeff) as (zeff x /e y ).  no definitive values about these indices x, y are given in the literature. the index x is said to lie between, 3.0 and 4.0, while for ‘y’ different values have been assigned, between 3.0 and 4.0. methodo...

background: it has recently been shown that the particle size of materials used for radiation shielding can affect the magnitude of radiation attenuation. over the past years, application of nano-structured materials in radiation shielding has attracted attention world-wide. the purpose of this study was to investigate the shielding properties of the lead-free shields containing micro and nano-...

To minimize the pulse-to-pulse variation, the LCLS FEL must operate at saturation, i.e. 10 orders of magnitude brighter spectral brilliance than 3-generation light sources. At this intensity, ultra-high vacuums and windowless transport are required. Many of the experiments, however, will need to be conducted at a much lower intensity thereby requiring a reliable means to reduce the x-ray intens...

PURPOSE Attenuation correction with an X-ray CT image is a new method to correct attenuation on SPECT imaging, but the effect of the registration errors between CT and SPECT images is unclear. In this study, we investigated the effects of the registration errors on myocardial SPECT, analyzing data from a phantom and a human volunteer. METHODS Registerion (fusion) of the X-ray CT and SPECT ima...

Introduction: Head-and-neck cancer is the sixth most common cancer worldwide with the number of cases consistently increasing in developing countries. Successful development of effective, safe and cost effective nanoprobes for head-and-neck cancer targeting imaging is a big challenge. This study is aimed to develop cysteamine-folate conjugated gold nanoparticles (F-Cys-AuNPs) a...

the advent of dual-modality pet/ct imaging has revolutionized the practice of clinical oncology, cardiology and neurology by improving lesions localization and the possibility of accurate quantitative analysis. in addition, the use of ct images for ct-based attenuation correction (ctac) allows to decrease the overall scanning time and to create a noise-free attenuation map (μmap). the near simu...

OBJECTIVE X-ray attenuation coefficients are used in common radiological, pathological and spectroscopic examinations and in the determination of the radiation dose distribution in biological tissues. In radiology, these coefficients enable diagnosis by differentiating the abnormal tissues from the normal ones using their morphological structure and contrast differences. In this study, our aim ...