Dual Energy Scanning
Dual-energy CT, sometimes called Spectral CT, is an imaging modality that makes use of two independent x-ray radiation spectra, enabling the investigation of physical matter which has different attenuation levels at different wavelengths. Whereas traditional single energy CT creates a single, peri-menopausal image, dual-energy images (at two different wavelengths) are used to create a variety of image types: correlated energy distribution (CDF) images, single-particle images, fractionated beam imaging (FFI), or stimulated emission scanning (SEM). The two independent x-ray radiation spectra from each x-ray source are combined with the corresponding channels in a common device, resulting in a single image. This method of producing detailed images enables both the acquisition and analysis of data. Unlike traditional CT applications, which are often carried out on patients’ normal tissues, dual-energy CT has the potential to be carried out on a variety of biological materials such as blood, saliva, or brain tissue.
CT is widely used in the field of medicine
to locate and examine cancerous growths and other abnormal lesions; it is also widely used in the diagnostic process of many other health disorders. Because the radiation from CT is slightly higher than the natural body radiation, it is important to control for body fat and tissue volume loss when determining the appropriate CT dosage. Since healthy individuals greatly outnumber ill patients when evaluating a patient’s CT scan results, a significant factor in the diagnostic utility of dual-energy CT is the ability to control for both losses of tissue and increase in tissue when necessary. To achieve this, medical facilities employ what is called fast-kvp switching. Fast-kvp switching involves using identical CT sources at an identical time and altering the polarity of each source so that the differences between the two are essentially zero.
To understand how fast-kvp switching may impact your imaging decision
it is necessary to first understand what it is not. Medical imaging equipment using fast-kvp switching is not a normal-cyanometer, thermal cyclorama, or electromagnetic detection device; it is not even a coherent detector. Non-contact medical imaging systems can incorporate a basis spectrum, but no scanner is based on a basis spectrum. A basis spectrum is the simplest type of detector to understand: it uses a collection of high frequency (high bandwidth) x wave vibrations of a given sample or a space object. These high-frequency vibrations are measured and converted by the system into an electric current, which can then be detected using a detector, such as a receiver or a detector with multiple input modes, such as an isotope generator or a magnetics-based detector.
The basic distinction between fast-kvp switching detectors
and a basis spectrum system is found in the acquisition system that they use. One type of acquisition system uses x-rays; the other uses linear attenuators or LASIK. The x-ray acquisition system makes use of low-frequency (LF) x rays, while the linear attenuator uses high-frequency (HFO) or ultra-sound waves. The two types of waves generate different artifacts in the acquisition process. One generates a background image at the time of acquisition, while the other produces an image after the acquisition process has been completed. Since the intensity of these two types of artifacts is different, the two artifacts cannot be compared with one another.
For medical imaging applications
it is more likely that you will need fast-kvp switching detectors, rather than basis-frequency or electromagnetic-based detectors. For this reason, your medical imaging acquisition system must have the appropriate hardware to detect and eliminate artifacts using fast-kvp switching. Some examples of this type of hardware include high-frequency domain integrated couplings (HFICs), digital x-rays (XDR), and high-frequency pulse sequences.
Since the energy of light can be thought of as an electric field
it is also important to understand how the absorption of light works and is controlled. In the case of absorption of light by matter, it is called the photoelectric effect. The absorption process creates binding energy that binds particles together. This binding energy is what creates the effect of light emission when light hits a surface.