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Cone Beam Computed Tomography
Cone beam computed tomography (or CBCT, also referred to as C-arm CT, cone beam volume CT, flat panel CT or Digital Volume Tomography (DVT)) is a medical imaging technique consisting of X-ray computed tomography where the X-rays are divergent, forming a cone. CBCT has become increasingly important in treatment planning and diagnosis in implant dentistry, ENT, orthopedics, and interventional radiology (IR), among other things. Perhaps because of the increased access to such technology, CBCT scanners are now finding many uses in dentistry, such as in the fields of oral surgery, endodontics and orthodontics. Integrated CBCT is also an important tool for patient positioning and verification in image-guided radiation therapy (IGRT). During dental/orthodontic imaging, the CBCT scanner rotates around the patient's head, obtaining up to nearly 600 distinct images. For interventional radiology, the patient is positioned offset to the table so that the region of interest is centered in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volume CT
Flat-panel Volume CT is a technique under development to make computed tomography images with improved performance (in particular, with improved spatial resolution). The key difference between volume CT and traditional CT is that volume CT uses a two-dimensional x-ray detector orientation (usually in a square panel orientation), to take multiple two-dimensional images. On the other hand, the conventional CT uses a one-dimensional x-ray detector orientation (a row of detectors) to take one-dimensional x-ray images. A CT machine consists of an x-ray source, an x-ray detector, a series of moving stages (Gantry) and computers to assemble the x-ray data into an image. The x-ray beam used in volume CT is cone shaped, in contrast to the fan shaped beam of the regular CT scanner. This cone shape allows the beam to cover the two-dimensional detector panel. See also * Industrial CT Scanning * Radiology * Computed Tomography * Medical Imaging * Cone beam reconstruction In microtomograph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Accelerator
A linear particle accelerator (often shortened to linac) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beamline. The principles for such machines were proposed by Gustav Ising in 1924, while the first machine that worked was constructed by Rolf Widerøe in 1928 at the RWTH Aachen University. Linacs have many applications: they generate X-rays and high energy electrons for medicinal purposes in radiation therapy, serve as particle injectors for higher-energy accelerators, and are used directly to achieve the highest kinetic energy for light particles (electrons and positrons) for particle physics. The design of a linac depends on the type of particle that is being accelerated: electrons, protons or ions. Linacs range in size from a cathode ray tube (which is a type of linac) to the linac at the SLAC National Accelerator Laboratory in Menlo Park ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Beam Radiotherapy
External beam radiotherapy (EBRT) is the most common form of radiotherapy (radiation therapy). The patient sits or lies on a couch and an external source of ionizing radiation is pointed at a particular part of the body. In contrast to brachytherapy (sealed source radiotherapy) and unsealed source radiotherapy, in which the radiation source is inside the body, external beam radiotherapy directs the radiation at the tumour from outside the body. Orthovoltage ("superficial") X-rays are used for treating skin cancer and superficial structures. Megavoltage X-rays are used to treat deep-seated tumours (e.g. bladder, bowel, prostate, lung, or brain), whereas megavoltage electron beams are typically used to treat superficial lesions extending to a depth of approximately 5 cm (increasing beam energy corresponds to greater penetration). X-rays and electron beams are by far the most widely used sources for external beam radiotherapy. A small number of centers operate experimental and pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Image-guided Radiation Therapy
Image-guided radiation therapy is the process of frequent imaging, during a course of radiation treatment, used to direct the treatment, position the patient, and compare to the pre-therapy imaging from the treatment plan. Immediately prior to, or during, a treatment fraction, the patient is localized in the treatment room in the same position as planned from the reference imaging dataset. An example of IGRT would include comparison of a cone beam computed tomography (CBCT) dataset, acquired on the treatment machine, with the computed tomography (CT) dataset from planning. IGRT would also include matching planar kilovoltage (kV) radiographs or megavoltage (MV) images with digital reconstructed radiographs (DRRs) from the planning CT. This process is distinct from the use of imaging to delineate targets and organs in the planning process of radiation therapy. However, there is a connection between the imaging processes as IGRT relies directly on the imaging modalities from planni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankle
The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at this joint are dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" (without qualifiers) can refer broadly to the region or specifically to the talocrural joint. The main bones of the ankle region are the talus (in the foot), and the tibia and fibula (in the leg). The talocrural joint is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus. The articulation between the tibia and the talus bears more weight than that between the smaller fibula and the talus. Structure Region The ankle region is found at the junction of the leg and the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot
The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws or nails. Etymology The word "foot", in the sense of meaning the "terminal part of the leg of a vertebrate animal" comes from "Old English fot "foot," from Proto-Germanic *fot (source also of Old Frisian fot, Old Saxon fot, Old Norse fotr, Danish fod, Swedish fot, Dutch voet, Old High German fuoz, German Fuß, Gothic fotus "foot"), from PIE root *ped- "foot". The "plural form feet is an instance of i-mutation." Structure The human foot is a strong and complex mechanical structure containing 26 bones, 33 joints (20 of which are actively articulated), and more than a hundred muscles, tendons, and ligaments.Podiatry Channel, ''Anatomy of the foot and ankle'' The joints of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Extremities
The human leg, in the general word sense, is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle, also known as the crus or, especially in non-technical use, the shank. Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person's mass. Female legs generally have greater hip anteversion and tibiofemoral angles, but shorter femur and tibial lengths than those in males. Structure In human anatomy, the lower leg is the part of the lower limb that lies between the knee and the ankle. Anatomists restrict the term ''leg'' to this use, rather than to the entire lower limb. The thigh is between the hip and knee and makes up the rest of the lower limb. The term ''lower limb'' or ''lower extremity'' is commonly used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Radiography
Dental radiographs, commonly known as X-rays, are radiographs used to diagnose hidden dental structures, malignant or benign masses, bone loss, and cavities. A radiographic image is formed by a controlled burst of X-ray radiation which penetrates oral structures at different levels, depending on varying anatomical densities, before striking the film or sensor. Teeth appear lighter because less radiation penetrates them to reach the film. Dental caries, infections and other changes in the bone density, and the periodontal ligament, appear darker because X-rays readily penetrate these less dense structures. Dental restorations (fillings, crowns) may appear lighter or darker, depending on the density of the material. The dosage of X-ray radiation received by a dental patient is typically small (around 0.150 mSv for a full mouth series), equivalent to a few days' worth of background environmental radiation exposure, or similar to the dose received during a cross-country airplane flig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Eruption
Tooth eruption is a process in tooth development in which the teeth enter the mouth and become visible. It is currently believed that the periodontal ligament plays an important role in tooth eruption. The first human teeth to appear, the deciduous (primary) teeth (also known as baby or milk teeth), erupt into the mouth from around 6 months until 2 years of age, in a process known as "teething". These teeth are the only ones in the mouth until a person is about 6 years old creating the primary dentition stage. At that time, the first permanent tooth erupts and begins a time in which there is a combination of primary and permanent teeth, known as the mixed dentition stage, which lasts until the last primary tooth is lost. Then, the remaining permanent teeth erupt into the mouth during the permanent dentition stage. Theories Although researchers agree that tooth eruption is a complex process, there is little agreement on the identity of the mechanism that controls eruption. There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology (that is, the relationship between the shape and form of the tooth in question and its inferred function) of the teeth of an animal. Animals whose teeth are all of the same type, such as most non-mammalian vertebrates, are said to have '' homodont'' dentition, whereas those whose teeth differ morphologically are said to have '' heterodont'' dentition. The dentition of animals with two successions of teeth (deciduous, permanent) is referred to as ''diphyodont'', while the dentition of animals with only one set of teeth throughout life is ''monophyodont''. The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed ''polyphyodont''. The dentition of animals in which the teeth are set in so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-dimensional Space
Three-dimensional space (also: 3D space, 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called ''parameters'') are required to determine the position (geometry), position of an element (i.e., Point (mathematics), point). This is the informal meaning of the term dimension. In mathematics, a tuple of Real number, numbers can be understood as the Cartesian coordinates of a location in a -dimensional Euclidean space. The set of these -tuples is commonly denoted \R^n, and can be identified to the -dimensional Euclidean space. When , this space is called three-dimensional Euclidean space (or simply Euclidean space when the context is clear). It serves as a model of the physical universe (when relativity theory is not considered), in which all known matter exists. While this space remains the most compelling and useful way to model the world as it is experienced, it is only one example of a large variety of spaces in three dimensions called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3D CT Impacted Wisdom Tooth
3-D, 3D, or 3d may refer to: Science, technology, and mathematics Relating to three-dimensionality * Three-dimensional space ** 3D computer graphics, computer graphics that use a three-dimensional representation of geometric data ** 3D film, a motion picture that gives the illusion of three-dimensional perception ** 3D modeling, developing a representation of any three-dimensional surface or object ** 3D printing, making a three-dimensional solid object of a shape from a digital model ** 3D display, a type of information display that conveys depth to the viewer ** 3D television, television that conveys depth perception to the viewer ** Stereoscopy, any technique capable of recording three-dimensional visual information or creating the illusion of depth in an image Other uses in science and technology or commercial products * 3D projection * 3D rendering * 3D scanning, making a digital representation of three-dimensional objects * 3D video game (other) * 3-D Secure, a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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