Materials Analysis Using Dual-Energy Spectroscopy
Dual-energy CT, sometimes called radiant CT, is an electrical tomography method that utilizes two independent x-ray photons, enabling the simultaneous analysis of two distinct absorbencies in objects which have varied attenuation characteristics at various energies. Whereas single energy tomography (SEM) creates a single picture with single photons, dual-energy imaging (DET) creates two independent images with complementary photons, providing a more complete representation of the target material. Unlike traditional tomography, however, it does not allow for fine-tuning or spatial resolution. The main advantage of using the dual-energy imaging method over conventional tomography is that it provides higher spatial resolution relative to non-dimensional tomographic techniques. Dual-energy CT’s main disadvantage is that it operates at a higher frequency than tomography and therefore offers less image quality.
The key components of a successful dual-energy tomography system
are the scanner and the camera. The scanner, which serves as both a source of radiation and a detector, is usually a solid-state device. Usually, these devices operate on closed-circuit television systems. The source of radiation can be any liquid or gas and the detector can either be part of the scanner or connected to the source. The two-dimensional image obtained from the system depends on the characteristics of the sources and the thickness of the target.
Another aspect of using dual-energy tomography
the diagnosis of brain cancer involves the development of a contrast between the radiation source and the reflected light. Typically, a conventional high-energy x-ray tube will provide a clear contrast between the radiation and the reflected light. A dual-energy tomograph, by contrast, may not offer such good visual quality, especially for low-contrast targets. One method of overcoming this problem involves the use of a contrast agent, applied to the scanned area.
The most commonly used contrast agent in the treatment of brain cancer
is fluorescein, a compound that is fluorescently colored. This compound provides an image of the internal organs and blood vessels with very high contrast, even after the radiation has been emitted. Because the contrast is high, the images obtained through dual-energy ct and computed tomography cannot completely substitute. According to a recent study, however, several hospitals are now processing brain scans and computed tomograms with a dual-energy ct strategy in place.
The reason why the contrast
is not always high after a radiation-based tomography or x-ray tube potential of a fluid or gas target is that, unlike liquids and gases, the absorption of x-rays and their energy goes beyond the radiation’s energy in the x-ray beam. The absorbed energy has a half-time that is significantly less than the total radiation absorbed, according to radiology experts. In the case of a liquid or gas, therefore, the contrast from the x-ray beam can compensate for the absorption phenomenon and provide excellent images. This is the reason why radiology imaging systems sometimes called “radio beams” are used instead of computed tomography (CT) or fluoroscopy (fluorescence) imaging systems, which rely on computed tomography or fluoroscopy to obtain a clear image of internal organs or tissues.
A drawback of a CT or fluoroscopy system
is that the energy used to create the image of the tissue is inversely proportional to the time for which it takes to change the Computed Tomography scanning energy to the absorption of light from the target. The longer the time for the energy chain, the lower the energy of the absorbed light and the lower the resolution of the resulting images. The opposite is true for dual-energy spectroscopy: shorter time for absorption and longer time for emission produces a higher resolution image. Because of this, the two methods can be used successfully to obtain similar results in materials analysis and mineral composition studies.