Computed tomography definition of computed tomography by. Computed tomography definition and meaning collins. The ct scanner is shaped like a ring or doughnut and the part of your body being. Definition facts about ctdefinition facts about ct computer tomography ct, originally known as computed axial tomography cat or ct scan and body section rentenography. Clinical computed tomography ct was introduced in 1971 limited to axial imaging of the brain in neuroradiology it developed into a versatile 3d whole body imaging modality for a wide range of applications in for example oncology, vascular radiology, cardiology, traumatology and interventional radiology. Download ct scan guidebook for parents to share with children. Diagnostic examinations of the head head scans and of other parts of the body body scans performed by computerized tomography ct scanners are covered if medical and scientific literature and opinion support the effective use of a scan for the condition, and the scan is. The text also includes features and resources to ease the transition into actual clinical. Tomography definition and meaning collins english dictionary. This is achieved by rotating a thin, fanshaped beam of xrays around the patient and measuring the intensity on the opposite side of the patient with a very large number of detectors. Clinical computed tomography ct was introduced in 1971 limited to axial imaging of the brain in neuroradiology it developed into a versatile 3d whole body imaging modality for a wide range of applications in for example. However, a computed tomography ct scan produces many 2d images of sections throughout the body using detectors arranged in a circular field, which can then be computer processed to give a threedimensional 3d reconstruction of the body. The ct scanner is programmed to give breathing instructions in 24 different languages. The origin of the word tomography is from the greek word tomos.
A ct imaging system produces crosssectional images or slices of anatomy. A tomographic image is an image of a slice through the body. Computed tomography ct, developed in the 1970s by william oldendorf and godfrey hounsfield, is an xray technique that allows for the visualization of 3 to 10mm approximately 0. Investigation of the eye formation in semihard cheese by. Computed tomography ct scans of a lymphedematous limb are characterized by a honeycomb pattern in the affected area. Computer assisted tomography an overview sciencedirect.
Abstract ct brain is the integral part of investigation in any case of craniocerebral trauma patient in emergency room. Although also based on the variable absorption of x rays by different tissues, computed tomography ct imaging, also known as cat scanning computerized axial tomography, provides a different form of imaging known as crosssectional imaging. Computed tomography scan showed bilateral atypical reticulonodular infiltrations predominant in the lower zones of the lungs figure. Scan your document according to the instructions for your scanner, and save it to your computer as a. Xray computed tomography cf, developed for medical purposes, uses scan techniques to secure multiple views of an object and provides ameans of obtaining nondestructive internal cross sections of objects. There is a table or bed that moves into the opening of the scanner during the scan and the patient may hear a humming noise similar to a washing machine. A ct scan or computed tomography scan formerly computerized axial tomography scan or cat scan makes use of computerprocessed combinations of many xray measurements taken from different angles to produce crosssectional tomographic images virtual slices of specific areas of a scanned object, allowing the user to see inside the object without cutting. Nevertheless, the lack of a standardized imaging protocol has slowed the adoption of cardiac computed tomography into clinical practice. An xray procedure that uses the help of a computer to produce a detailed picture of a cross section of the body. Purpose ct scans are used to image a wide variety of body structures and internal organs.
Arterial occlusion, nci thesaurus also called computed tomography scan, computerized axial tomography scan, computerized tomography, and ct scan. Ct scans are the chief competitor to ultrasound and can yield higher quality images not disrupted by bone or gas. Ct was introduced into clinical practice into 1971 with a scan of a cystic. Computed tomography ct scan for children k h h a n y k t i v y h u s m m t f s n m y b e r g d l y a n f d x y z z k i r k e o c x y g o l o i d a r n s z t b e. A computerized tomography scan ct or cat scan uses computers and rotating xray machines to create crosssectional images of the body. The word tomography is derived from ancient greek tomos, slice, section and. A computed tomography scan of the skull demonstrated a mixeddensity soft. Cat regimen, nci dictionary the relationship between various air pollutants and. Computed tomography scans definition computed tomography ct scans are completed with the use of a 360degree xray beam and computer production of images.
Computed tomography ct, sometimes called computerized tomography or computed axial tomography cat, is a noninvasive medical examination or procedure that uses specialized x. This is the basic idea behind computed tomography where multiple xrays scans from different angles are put together to form an image. The radiation dose of a ct scanner is much higher than. However, cardiac computed tomography offers improved imaging with highquality multiplanar and 3dimensional reconstructed images.
These scans allow for crosssectional views of body organs and tissues. History 1924 mathematical theory of tomographic image. Ct scanning is fast, painless, noninvasive and accurate. These detectors are connected to sophisticated computers which generate images after image processing. What is a computed tomography ct or cat scan used for. Introduction xraycomputed tomography ct has rapidly evolved in terms of both technical performance and clinical use. Electron tomography et, also known as electron microscope tomography, is similar to computerized tomography described in chapter 1. Since 1980, the number of annual ct articles in radiology has ranged from 86 in 1992 to 172 in 2005. In fact, art was used in the first commercial medical ct scanner released in 1972, the emi mark i. Computed tomographic pulmonary angiography and venography. Computed tomography also known as a ct or cat scan uses a narrow beam of xrays and highpowered computers to generate images of bones and softtissues in the body. The amount of x rays absorbed contributes to the radiation dose to the patient.
Computed tomography ct imaging is also known as cat scanning computed axial tomography. In et, the specimen is tilted within the electron microscope to produce tem images from many different perspectives to reconstruct a three. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, quantum information, and other areas of science. Tomography is imaging by sections or sectioning through the use of any kind of penetrating wave. Cat, ct, computed axial tomography, computerized axial tomography, computerized tomography type of. Severe pneumonia and human bocavirus in adult paranasal sinus computed tomography scan findings in patients with cystic fibrosis. In emergency cases, it can reveal internal injuries and bleeding quickly enough to help save lives. Tomography is from the greek word tomos meaning slice or section and graphia meaning describing ct was invented in 1972 by british engineer godfrey hounsfield of emi laboratories, england and by south africaborn physicist allan cormack of tufts university, massachusetts. This new technique of computed tomography ct reconstructs a crosssectional image of the body from a virtual pile of xray photographs. The term computed tomography, or ct, refers to a computerized xray imaging procedure in which a narrow beam of xrays is aimed at a patient and quickly rotated around the body, producing signals that are processed by the machines computer to generate crosssectional imagesor slicesof the body. Below is a list of the mostcommon ct procedures offered at the accredited s. Pdf an overview of industrial xray computed tomography. Pdf how to read a computed tomography scan for traumatic. The number of scans in a given study is, of course, an important factor in determining the dose.
It uses a combination of xrays and a computer to create pictures of your organs, bones, and other tissues. A computed tomography ct or cat scan allows doctors to see inside your body. Computeraided tomography article about computeraided. Representative calculated organ doses for frequently used machine settings1 are shown in figure 3a and 3b for a single ct scan of the head and of the abdomen, the two most common types of ct scan. Computed tomography how is computed tomography abbreviated. In other words, while facilities may own ct without radiologist legally, they. A ct scan, or computed tomography scan is a medical imaging procedure that uses. Key words ct scan, traumatic brain injury, skull fracture, head injury.
Ct scans may be used to diagnose headache when neuroimaging is indicated and mri is not. A type of computed tomography in which images are taken during the time when the contrast medium has passed the heart and entered the arteries. Scan and edit a document word microsoft office support. Xray computed tomography, eye formation, iterative artifact reduction, beam hardening created date. Arterial occlusion, nci thesaurus following exposure to this agent, egfr expression status can be determined and egfr overexpressing tumor cells can be visualized using positron emission tomography. In a ct scan, the imaging equipment is moved around a patient to generate different images of a slice of the brain. A specialized type of xray imaging that uses highly focused and relatively low energy radiation to produce detailed twodimensional images of soft tissue structures, particularly the brain. Expert recommendations on cardiac computed tomography for. The total number of ct articles in radiology through 20 was 4084, which represented 4.
Computed tomography ct of the abdomen and pelvis is a diagnostic imaging test used to help detect diseases of the small bowel, colon and other internal organs and is often used to determine the cause of unexplained pain. These images provide more detailed information than normal. The word tomography is deriv ed from two greek words, tomos meaning slice images are taken through the volume of the object and graphein meaning to write. The crosssectional images generated during a ct scan can be reformatted in multiple planes, and can even generate threedimensional images which can be viewed on a computer monitor. The spatial resolution of modern scanners is on the order of i mm, providing a potential means of detecting. Ideally suited for ct courses in radiologic technology programs, or for standalone ct programs, this text prepares students both for mastery of the american registry of radiologic technologists arrt general radiography and computed tomography exams. Assessment of image quality parameters for computed. It has become one of the most important of all xray procedures worldwide 1. The aim of computed tomography ct is to produce an image of a slice of the body.
Of course this also means that the radiation dose for a ct scan is larger than for a regular single xray scan. The word tomography is derived from the greek tome slice and graphein to write. Ct scanning sometimes called cat scanning is short for computerized tomography and uses specialized xray equipment and sophisticated computers to create images of the inside of the body. Brief history of ct ct scan imaginis the womens health. Ct scans provide clearer and more detailed images than regular xray exams. On each page you can find detailed information about the. Ordinary roentgenography results in the production on film of an overall. Tomography is from the greek word tomos meaning slice or section and graphia meaning describing. Xradiation, xraying obtaining images by the use of x rays. Computed tomography ct is a diagnostic imaging test used to create detailed images of internal organs, bones, soft tissue and blood vessels. Computed tomography ct body computed tomography ct of the body uses sophisticated xray technology to help detect a variety of diseases and conditions. Computer axial tomography definition of computer axial.
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