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Objective To investigate the role of dual-layer detector energy spectral CT in resting myocardial perfusion imaging for patients with normal coronary artery. Methods One hundred and fifty-six patients with suspected coronary heart disease underwent dual-layer detector energy spectral CT coronary angiography,and resting myocardial perfusion imaging was performed for 28 patients with normal coronary artery.According to American Heart Association's 17-segmentmodel,the iodine density and effective atomic number(Z
Sujets)
Humains , Angiographie par tomodensitométrie , Coronarographie , Vaisseaux coronaires/imagerie diagnostique , Imagerie de perfusion myocardique , TomodensitométrieRésumé
@#Introduction: In medical physics applications, effective atomic numbers are often employed to set apart and specify the interaction of ionizing radiation with matter. Methods: The effective atomic number of soy-lignin bonded with Rhizophora spp. particleboards were analyzed using Energy Dispersive X-ray analysis and Carbon Hydrogen Nitrogen Analyzer. The effective atomic number were compared and recorded with reference to the effective atomic value of water. Results: The result showed that the effective atomic number calculated for adhesive bound Rhizophora spp. samples were close to effective atomic value of water, with 3.34 – 3.47 % differences by using Energy Dispersive X-ray and 6.47 – 6.78 % differences by using Carbon Hydrogen Nitrogen analysis. The result revealed that through Energy Dispersive X-ray method, the effective atomic number was much closer to water compared to Carbon Hydrogen Nitrogen analysis. Conclusion: Despite the availability of hydrogen content in the samples in Carbon Hydrogen Nitrogen analysis, Energy Dispersive X-ray method was much more preferred and gave better result compared to Carbon Hydrogen Nitrogen analysis thus provide a compelling argument for the use of Energy Dispersive X-ray method to measure the effective atomic number of Rhizophora spp. particleboard in medical physics applications.
Résumé
Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.
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Humains , Imagerie diagnostique , Filtration , Iode , Poumon , Exposition aux rayonnements , Acide urique , XénonRésumé
Se calcularon los números atómicos efectivos totales y parciales de tejidos mamarios sanos y malignos, utilizando el software WinXcom y su base de datos; en el rango de energía de 10 keV ≤ E ≤ 500 keV. Los cálculos realizados, correspondientes a los procesos microscópicos relevantes involucrados, muestran que mediantes los mismos es posible describir y diferenciar los tejidos mamarios sanos y malignos entre sí.
We calculated effective atomic numbers partial of healthy and malignant breast tissues, using WinXcom software and database, in the energy range 10 keV ≤ E ≤ 500 keV. Calculations corresponding to the relevant microscopic processes involved, show that is possible describe and differentiate healthy and malignant breast tissues each other using partial effective atomic numbers.
Os números atômicos total e parciais de tecidos mamários saudáveis e malignas foram calculados utilizando o software WinXcom e o seu banco de dados, na faixa de energia de 10 keV ≤ E ≤ 500 keV. Os cálculos realizados, correspondentes aos processos microscópicos relevantes envolvidos mostram que pode-se descrever e diferenciar os tecidos mamários saudáveis e malignas.