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Helical (or spiral) cone beam computed tomography is a type of three-dimensional computed tomography (CT) in which the source (usually of X-rays) describes a helical trajectory relative to the object while a two-dimensional array of detectors measures the transmitted radiation on part of a cone of rays emanating from the source.
In modern (helical) CT, the source/detector makes at least a complete 180-degree rotation about the subject obtaining a complete set of data from which images may be reconstructed. Digital tomosynthesis, on the other hand, only uses a limited rotation angle (e.g., 15-60 degrees) with a lower number of discrete exposures (e.g., 7-51) than CT.
Multiplanar reconstruction (MPR) is the process of converting data from one anatomical plane (usually transverse) to other planes. It can be used for thin slices as well as projections. Multiplanar reconstruction is possible as present CT scanners provide almost isotropic resolution. [108] MPR is used almost in every scan.
Cone-beam spiral computed tomography (CT) is a medical imaging technology that has impacted healthcare since its development in the early 1990s. [1] [2] This technology offers advancements over traditional fan-beam CT, including faster scanning speed, higher image quality, and the ability to generate true three-dimensional volumes, even with contrast-enhancement.
Tomographic reconstruction: Projection, Back projection and Filtered back projection. Tomographic reconstruction is a type of multidimensional inverse problem where the challenge is to yield an estimate of a specific system from a finite number of projections. The mathematical basis for tomographic imaging was laid down by Johann Radon.
Cone beam reconstruction uses a 2-dimensional approach for obtaining projection data. Instead of utilizing a single row of detectors, as fan beam methods do, a cone beam systems uses a standard charge-coupled device camera, focused on a scintillator material.
Otoplasty (surgery of the ear) was developed in ancient India and is described in the medical compendium, the Sushruta Samhita (Sushruta's Compendium, c. 500 AD).The book discussed otoplastic and other plastic surgery techniques and procedures for correcting, repairing and reconstructing ears, noses, lips, and genitalia that were amputated as criminal, religious, and military punishments.
An extension of this technique uses single particle methods to build up a three-dimensional reconstruction of the particle. Using cryo-electron microscopy it has become possible to generate reconstructions with sub- nanometer resolution and near-atomic resolution [ 2 ] [ 3 ] first in the case of highly symmetric viruses, and now in smaller ...