Because film can be wet-mounted to the scanner drum, which enhances sharpness and masks dust and scratches, and because of the exceptional sensitivity of the PMTs, drum scanners are capable of capturing very subtle details in film originals. Laser scanning is the controlled deflection of laser beams, visible or invisible. " On the other hand, a recent paper analyzing the data of patients who received high cumulative doses showed a high degree of appropriate use. The result of a CT scan is a volume of voxels, which may be presented to a human observer by various methods, which broadly fit into the following categories: Technically, all volume renderings become projections when viewed on a 2-dimensional display, making the distinction between projections and volume renderings a bit vague. The process of whole-surface-at-once capturing has the benefit of increasing reaction time for the work flow of scanning. Most scanners use ISIS or TWAIN device drivers to scan documents into TIFF format so that the scanned pages can be fed into a document management system that will handle the archiving and retrieval of the scanned pages. Modern CT machines typically generate 64-640 slices per scan. Computed tomography was originally known as the "EMI scan" as it was developed in the early 1970s at a research branch of EMI, a company best known today for its music and recording business. This left-right interchange corresponds to the view that physicians generally have in reality when positioned in front of patients. All these scanners produce two-dimensional images of subjects that are usually flat, but sometimes solid; 3D scanners produce information on the three-dimensional structure of solid objects.  However, established guidelines advise that patients without a prior history of cancer and whose solid nodules have not grown over a two-year period are unlikely to have any malignant cancer. While paper feeding and scanning can be done automatically and quickly, preparation and indexing are necessary and require much work by humans. Many can scan both small documents such as business cards and till receipts, and letter-sized documents. Types of Scanners 1.  Those in the nuclear industry in the United States are limited to doses of 50 mSv a year and 100 mSv every 5 years.. Modern scanners typically use a charge-coupled device (CCD) or a contact image sensor (CIS) as the image sensor, whereas drum scanners, developed earlier and still used for the highest possible image quality, use a photomultiplier tube (PMT) as the image sensor. guns, knives, liquid containers). OCR software converts graphical images of text into standard text that can be edited using common word-processing and text-editing software; accuracy is rarely perfect. There are many different scanners, and many of those scanners use different protocols. , "A flatbed scanner is usually composed of a glass pane (or platen), under which there is a bright light (often xenon, LED or cold cathode fluorescent) which illuminates the pane, and a moving optical array in CCD scanning. Another category of document scanner is the document camera. Using contrast material can also help to obtain functional information about tissues. (2009), Office Management: Developing Skills for Smooth Functioning, Global India Publications, 312 pp. Most adverse health effects of radiation exposure may be grouped in two general categories: The added lifetime risk of developing cancer by a single abdominal CT of 8 mSv is estimated to be 0.05%, or 1 one in 2,000.. In volume rendering, transparency, colors and shading are used to allow a better representation of the volume to be shown in a single image. प्रिंटर एक ऑनलाइन आउटपुट डिवाइस (Online Output Device) है जो कंप्यूटर से प्राप्त जानकारी को कागज पर छापता है कागज पर आउटपुट (Output) की यह प्रतिलिपि हार्ड कॉपी (Hard Copy) कहलाती है कंप्यूटर से जानकारी का आउटपुट (Output) बहुत तेजी से मिलता है और प्रिंटर (Printer) इतनी तेजी से कार्य नहीं कर पाता इसलिये यह आवश्यकता महसूस की गयी कि जानकारियों को प्रिंटर (Printer) में ही स्टोर (Store) किया जा सके इसलिये प्रिंटर (Printer) में भी एक मेमोरी (Memory) होती है जहाँ से यह परिण… . Impact printers. Technical difficulties arise from the books usually being bound and sometimes fragile and irreplaceable, but some manufacturers have developed specialized machinery to deal with this. For the latter, the scanned result is a non-compressed RGB image, which can be transferred to a computer's memory. In addition to the use of intravenous contrast, orally administered contrast agents are frequently used when examining the abdomen. The first use of barcodes was to label railroad rolling stock.They became a big success when they were used in supermarket checkout systems. Fingerprint scanners are security systems of biometrics. This allows bends in a vessel to be "straightened" so that the entire length can be visualised on one image, or a short series of images. The device is moved on the paper by hand. This allows batch scans and transparent network access without any special support from the device driver. For example, the bones of the pelvis could be displayed as semi-transparent, so that, even at an oblique angle, one part of the image does not conceal another. Meierhold, N., Spehr, M., Schilling, A., Gumhold, S. and Maas, H.G.  'ChromImage' is allegedly the first commercial flatbed scanner densitometer. The radiation dose for a particular examination depends on multiple factors: volume scanned, patient build, number and type of scan sequences, and desired resolution and image quality. Another qualifying parameter for a scanner is its resolution, measured in pixels per inch (ppi), sometimes more accurately referred to as Samples per inch (spi). A CT scan of the heart is performed to gain knowledge about cardiac or coronary anatomy. The equivalent dose is the effective dose of a case, in which the whole body would actually absorb the same radiation dose, and the sievert unit is used in its report. Some are portable, powered by batteries and with their own storage, eventually transferring stored scans to a computer over a USB or other interface.  There are a number of reasons for this including: legal concerns, financial incentives, and desire by the public. Capturing images on document cameras differs from that of flatbed and Automatic document feeder (ADF) scanners in that there are no moving parts required to scan the object.  While there is some variation, most people (99%) received less than 7 mSv per year as background radiation. From this, a three-dimensional model can be constructed using edge detection image processing algorithms and displayed on screen. Drum scanners capture image information with photomultiplier tubes (PMT), rather than the charge-coupled device (CCD) arrays found in flatbed scanners and inexpensive film scanners.  For this reason, and because no research provides supporting evidence that intensive surveillance gives better outcomes, and because of risks associated with having CT scans, patients should not receive CT screening in excess of those recommended by established guidelines.. Image scanners are usually used in conjunction with a computer which controls the scanner and stores scans. Document cameras usually also require a small amount of space and are often portable.. The International Commission on Radiological Protection estimates that the risk to a fetus being exposed to 10 mGy (a unit of radiation exposure) increases the rate of cancer before 20 years of age from 0.03% to 0.04% (for reference a CT pulmonary angiogram exposes a fetus to 4 mGy). People have a pattern of ridges on their fingers. Consumer-level flatbed photo scanners have a dynamic range in the 2.0–3.0 range, which can be inadequate for scanning all types of photographic film, as Dmax can be and often is between 3.0d and 4.0d with traditional black-and-white film.  Dense minerals such as pyrite and barite appear brighter and less dense components such as clay appear dull in CT images. It is commonly used to investigate acute abdominal pain. Although images produced by CT are generally faithful representations of the scanned volume, the technique is susceptible to a number of artifacts, such as the following:Chapters 3 and 5, An important issue within radiology today is how to reduce the radiation dose during CT examinations without compromising the image quality. , Since its introduction in the 1970s, CT has become an important tool in medical imaging to supplement X-rays and medical ultrasonography. In North America supermarkets, Scanning devices include barcode reader’s mark- and character recognition devices fax machines and imagine systems. In practice, there are often problems with an application communicating with a scanner. Industrial CT scanning has been utilized in many areas of industry for internal inspection of components.  Third, CT scanning enables multiplanar reformatted imaging: scan data can be visualized in the transverse (or axial), coronal, or sagittal plane, depending on the diagnostic task. An image scanner—often abbreviated to just scanner, is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. CT scanning of the head is also used in CT-guided stereotactic surgery and radiosurgery for treatment of intracranial tumors, arteriovenous malformations, and other surgically treatable conditions using a device known as the N-localizer.  Office document scanners can have a dynamic range of less than 2.0d. Many scanners offer this as an option. Modern scanners allow the scan data to be reformatted as images in other planes. Indirect (network) connection to a computer. Scanner manufacturers usually have their own name attached to this technique. TWAIN is used by most scanners. Types of fingerprint scanners There are four types of fingerprint scanner: the optical scanner, the capacitance scanner, the ultrasonic scanner, and the thermal scanner.  MPR is frequently used for examining the spine. First, CT eliminates the superimposition of images of structures outside the area of interest. Early estimates of harm from CT are partly based on similar radiation exposures experienced by those present during the atomic bomb explosions in Japan after the Second World War and those of nuclear industry workers. A rotary scanner, used for high-speed document scanning, is a type of drum scanner that uses a CCD array instead of a photomultiplier. , An incidentally found nodule in the absence of symptoms (sometimes referred to as an incidentaloma) may raise concerns that it might represent a tumor, either benign or malignant. Pushkar O.I., (2011), Information systems and technologies. This ranges from arteries serving the brain to those bringing blood to the lungs, kidneys, arms and legs. Scanned laser beams are used in some 3-D printers, in rapid prototyping, in machines for material processing, in laser engraving machines, in ophthalmological laser systems for the treatment of presbyopia, in confocal microscopy, in laser printers, in laser shows, in Laser TV, and in barcode scanners. In the biomedical research area, detection devices for DNA microarrays are called scanners as well. Pixel values of 0 and lower, are displayed as black; values of 80 and higher are displayed as white; values within the window are displayed as a grey intensity proportional to position within the window. The attenuation of metallic implants depends on the atomic number of the element used: Titanium usually has an amount of +1000 HU, iron steel can completely extinguish the X-ray and is, therefore, responsible for well-known line-artifacts in computed tomograms. The sample size is the area that the scanner encoder reads to create an individual pixel. The personnel that perform CT scans are called radiographers or radiologic technologists.  Thus, as is shown in the table above, the actual radiation that is absorbed by a scanned body part is often much larger than the effective dose suggests. Hand scanner. It has more recently been used for preventive medicine or screening for disease, for example CT colonography for people with a high risk of colon cancer, or full-motion heart scans for people with high risk of heart disease. These are the dominant type of scanners on the market because they have been manufactured longer and offer a lower cost of production and purchase. Documents are best stored in TIFF or PDF format; JPEG is particularly unsuitable for text. They are used to unlock doors and in other security applications. Pictures are normally stored in image formats such as uncompressed Bitmap, "non-lossy" (lossless) compressed TIFF and PNG, and "lossy" compressed JPEG. While drum scanners are capable of scanning both reflective and transmissive artwork, a good-quality flatbed scanner can produce good scans from reflective artwork. Inexpensive portable battery-powered "glide-over" hand scanners, typically capable of scanning an area as wide as a normal letter and much longer remain available as of 2014[update]. Recent studies on 2.5 million patients and 3.2 million patients have drawn attention to high cumulative doses of more than 100 mSv to patients undergoing recurrent CT scans within a short time span of 1 to 5 years. Document cameras capture the whole document or object in one step, usually instantly. The pantelegraph (Italian: pantelegrafo; French: pantélégraphe) was an early form of facsimile machine transmitting over normal telegraph lines developed by Giovanni Caselli, used commercially in the 1860s, that was the first such device to enter practical service. , Side effects from contrast agents, administered intravenously in some CT scans, might impair kidney performance in patients that have kidney disease, although this risk believed to be lower than previously thought.  Some early research has found the dose reduction potential of photon counting CT for breast imaging to be very promising. ", This type of scanner is sometimes called a slide or transparency scanner and it works by passing a narrowly focused beam of light through the film and reading the intensity and color of the light that emerges.  Traditionally, cardiac CT scans are used to detect, diagnose, or follow up coronary artery disease. Often, images are taken both with and without radiocontrast.  As of 2007 in the United States a proportion of CT scans are performed unnecessarily.  These incidents are believed to be due to human error.. Many areas of the country now require a more advanced type of scanner (trunking or trunking and digital) to monitor state-of-the-art local, county and/or state radio systems. , which counteracts existing criticisms some investigators may have on the effects of protracted versus acute exposure. Dubey, N.B. It enables acquisition of TLC plate images and quantification of chromatograms by use of Galaxie-TLC software.  Density range is the space taken up in the 0 to 5 scale, and Dmin and Dmax denote where the least dense and most dense measurements on a negative or positive film.  Trichromatic Color Analyser is allegedly the first distributable system using a flatbed scanner as a tristimulus colorimetric device. From 2000 all-in-one multi-purpose devices became available which were suitable for both small offices and consumers, with printing, scanning, copying, and fax capability in a single apparatus which can be made available to all members of a workgroup. Higher resolution is not always suitable for any given scenario, such as detection of small pulmonary masses. It is used to scan physical documents into their digital forms that can be stored, edited, transferred and emailed digitally. Spinning tube, commonly called spiral CT, or helical CT is an imaging technique in which an entire X-ray tube is spun around the central axis of the area being scanned. Kodak Vision 3 has 18 stops. This is typically done via a process of "windowing", which maps a range (the "window") of pixel values to a grayscale ramp.  PCDs have only recently become feasible in CT scanners due to improvements in detector technologies that can cope with the volume and rate of data required. Radiocontrasts for X-ray CT are, in general, iodine-based. , CT scanning has also found an application in transport security (predominantly airport security where it is currently used in a materials analysis context for explosives detection CTX (explosive-detection device) and is also under consideration for automated baggage/parcel security scanning using computer vision based object recognition algorithms that target the detection of specific threat items based on 3D appearance (e.g. Two-dimensional CT images are conventionally rendered so that the view is as though looking up at it from the patient's feet. /O.I. In Europe, services similar to a wirephoto were called a Belino. For example, CT images of the brain are commonly viewed with a window extending from 0 HU to 80 HU. Once a vessel has been "straightened" in this way, quantitative measurements of length and cross sectional area can be made, so that surgery or interventional treatment can be planned.  However, a lumbar spine x-ray has a similar dose as a head CT. Articles in the media often exaggerate the relative dose of CT by comparing the lowest-dose x-ray techniques (chest x-ray) with the highest-dose CT techniques. The detection is done via CCD or a photomultiplier tube. In response to increased concern by the public and the ongoing progress of best practices, The Alliance for Radiation Safety in Pediatric Imaging was formed within the Society for Pediatric Radiology. Typically, in addition to the scanning utility, some type of image-editing application (such as Adobe Photoshop), and optical character recognition (OCR) software are supplied. Under the glass, there is a moving Image Sensor. The table reports average radiation exposures, however, there can be a wide variation in radiation doses between similar scan types, where the highest dose could be as much as 22 times higher than the lowest dose. Surface rendering is limited in that it will display only surfaces that meet a threshold density, and will display only the surface that is closest to the imaginary viewer. Since the introduction of the USB standard, it is the interface most commonly used. The situation as of 2014[update] was that only a few companies continued to manufacture and service drum scanners. Drum Scanner. This process can sometimes be automated to some extent, but it often requires manual labour performed by data-entry clerks. Prior to every CT examination, evaluate the appropriateness of the exam whether it is motivated or if another type of examination is more suitable. The radiation dose reported in the gray or mGy unit is proportional to the amount of energy that the irradiated body part is expected to absorb, and the physical effect (such as DNA double strand breaks) on the cells' chemical bonds by X-ray radiation is proportional to that energy. In 2010 scanning technologies were combining 3D scanners with digital cameras to create full-color, photo-realistic 3D models of objects.. People with mild kidney impairment are usually advised to ensure full hydration for several hours before and after the injection. These scanners are high-resolution systems (up to 1 µm/ pixel), similar to microscopes. Typically, documents are placed on a flat surface, usually the office desk, underneath the capture area of the document camera. For evaluation of chronic interstitial processes such as emphysema, and fibrosis, thin sections with high spatial frequency reconstructions are used; often scans are performed both on inspiration and expiration.  CT can distinguish between tissues that differ in radiographic density by 1% or less. Axial images through the spine will only show one vertebral body at a time and cannot reliably show the intervertebral discs.  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