SPECT detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. Attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. In our study efficacy of Chang method was evaluated for attenuation purpose, using a custom made heart phantom. Due to d...

  Introduction: Attenuation correction is a useful process for improving myocardial perfusion SPECT and is dependent on activity and distribution of attenuation coefficients in the body (attenuation map). Attenuation artifacts are a common problem in myocardial perfusion SPECT. The aim of this study was to compare the effect of attenuation correction using different a...

Natural attenuation assessment data, collected at a Superfund site located in Louisiana, USA, are presented. The study site is contaminated with large quantities of DNAPL waste products. Source characterization data indicated that chlorinated ethene and ethane compounds are the major contaminants of concern. This case study illustrates the steps involved in implementing the U.S. EPA's [U.S. EPA...

Knowledge of x-ray attenuation is essential for developing and evaluating x-ray imaging technologies. For instance, techniques to better characterize cysts at mammography screening would be highly desirable to reduce recalls, but the development is hampered by the lack of attenuation data for cysts. We have developed a method to measure x-ray attenuation of tissue samples using a prototype phot...

Molecular biologists have long recognized carcinogenesis as an evolutionary process that involves natural selection. Cancer is driven by the somatic evolution of cell lineages. In this study, the evolution of somatic cancer cell lineages during carcinogenesis was modeled as an equilibrium point (ie, phenotype of attractor) shifting, the process of a nonlinear stochastic evolutionary biological ...

Neuroleptics are widely prescribed drugs for the treatment of schizophrenia and related psychiatric disorders. Tardive dyskinesia (TD) is a late complication of prolonged neuroleptic treatment. Despite much research, the pathogenesis of TD remains elusive. It may be caused by loss of dopaminergic cells, due to free radicals as a product of high synaptic dopamine levels. Tardive dyskinesia has b...

Neuroleptics are widely prescribed drugs for the treatment of schizophrenia and related psychiatric disorders. Tardive dyskinesia (TD) is a late complication of prolonged neuroleptic treatment. Despite much research, the pathogenesis of TD remains elusive. It may be caused by loss of dopaminergic cells, due to free radicals as a product of high synaptic dopamine levels. Tardive dyskinesia has b...

BACKGROUND AND OBJECTIVES: Very low grid power penetration in some urban areas has led to telecoms companies investing massively in the deployment of diesel generators (DGs). These deployments have led to diesel and waste oil spill at base transceiver station (BTS) sites during maintenance cycles, impacting the environment and human activities. The objective of this study is to...