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Fluoroscopy
Fluoroscopy is used to study moving body structures in real time. A fluoroscope is used to produce a continuous (advanced fluoroscopy machines provide pulsed techniques to lower the amount of radiation) x-ray beam, passing through the body part being examined and transmitted to a monitor so that dynamic images of deep tissue structures can be visualized. Fluoroscopy is primarily used for gastrointestinal exams, genitourinary studies, cardiovascular imaging and for invasive procedures performed by interventional radiologists and angiographers under fluoroscopic guidance. Fluoroscopy can also produce a static record of an image formed on the output phosphor of an image intensifier. The image intensifier is an x-ray image receptor that increases the brightness of a fluoroscopic image by electronic amplification and image minification. Modern fluoroscopy systems combine less radiation with better image quality due to digital image processing and flat-panel technology.
Roentgen's discovery of x-rays related directly to fluoroscopy, because fluorescence on the material in the room draws his attention to the x-ray's properties. In 1896, Thomas A. Edison created the first fluoroscope, consisting of a zinc-cadmium sulfide screen that was placed above the patient's body in the x-ray beam and provides a faint fluorescent image. In first-generation units, the exam room required complete darkness. The users wear red goggles for up to 30 minutes prior to the examination, to adapt the eyes to darkness. After this, the radiologist stared directly at a yellow-green fluorescent image through a sheet of lead to prevent the x-ray beam from striking the eyes.
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Cinefluorography
A cinefluorography produces a movie (cine) film from an image intensifier during x-rays examinations (often called videofluorography, cineradiography or cine). Cinefluorography is always monitored on the TV screen normally used for fluoroscopy. The image from the output screen of the image intensifier is split with a semi-transparent mirror into two output ports; one leading to the movie camera and the other to the fluoroscopy camera. Most of the light is directed to the cine camera. The image on the monitor does not suffer in quality due to the fact that the tube current for cinefluorography is about 100 times higher than for common fluoroscopy.
The x-ray generator pulses are synchronized with the movements of the cine camera, so that no x-rays are emitted when the film is moved forward to the next frame. The needed very accurate synchronization of the x-ray generator can be achieved by use of high voltage switching in the secondary circuit of the constant potential x-ray generator, by starting and stopping the inverter in a medium frequency generator or by using a grid controlled x-ray tube.
Arthrogram
An arthrogram is an x-ray fluoroscopy of a joint performed with a sequential digital subtracted spot films after injection of a contrast agent.

See Arthrography.
Contrast Media Injector
Contrast media injectors are part of the medical equipment used to deliver fluids in examinations such as CT, MRI, fluoroscopy and angiography. Many of these diagnostic imaging procedures include the administration of intravenous contrast agents to enhance the blood and perfusion in tissues.

Mainly there are two types of injector technology:
Piston-based systems use a plunger/piston to move a piston in the cylinder of a reservoir, which works in two directions to first fill the reservoir and then deliver the fluid from the reservoir to the patient, similar to a hand-held syringe.
Peristaltic-pump-based systems operate as rotary pumps that use rollers to compress sections of flexible tubing, drawing fluid directly from the supply source and delivering it to the patient.

See also Single-Head Contrast Media Injector, Dual-Head CT Power Injector, Syringeless CT Power Injector.

The use of x-ray contrast agents in computed tomography (CT) began with a hand injection by the radiologist in the scan room. During its history, CT scanners have made great improvements in speed and image quality. Actual CT systems with multiple detectors allow scan times of a few seconds per body region. Some CT protocols require multiphase scans, where a body region is imaged with a single bolus of contrast in different blood flow phases. Automatic power (pressure) contrast media injectors are required to provide precise control of flow rate, volume and timing of injection. The use of a saline bolus following contrast administration reduces the volume of contrast required.

Most relevant topics for the use of a power injector in medical imaging procedures such as contrast enhanced computed tomography (CECT):
Avoidance of microbiologic contamination;
workflow efficiency in the use of the contrast media injector;
contrast cost and waste volume;
reimbursement.

Must have basic injector control options:
Flow rate with a usual range from 0.1 to 10 mL/sec in 0.1 mL/sec increments; some injectors can be set to inject in ml/min or ml/hour;
volume range from 1 mL to 200 mL for contrast and saline phases;
pressure limit typically programmable from 50 psi to 300 psi in 1 psi increments (also displayable in kPa and kg/cm²).

Examples of other injector control options:
Warmer/heater; an increase in temperature of the contrast medium results in a decrease in its viscosity; warmed contrast media are less viscous and offer lesser resistance;
pre-filled syringes; the compatibility with many selected syringes makes it easy to change and select the appropriate contrast medium for each patient;
injection reports accessible via RIS/PACS for dose management systems and records of prior injections.

Diagnostic Imaging
Imaging refers to the visual representation of an object. Today, diagnostic imaging uses radiology and other techniques, mostly noninvasive, to create pictures of the human body. Diagnostic radiography studies the anatomy and physiology to diagnose an array of medical conditions. The history of medical diagnostic imaging is in many ways the history of radiology. Many imaging techniques also have scientific and industrial applications. Diagnostic imaging in its widest sense is part of biological science and may include medical photography, microscopy and techniques which are not primarily designed to produce images (e.g., electroencephalography and magnetoencephalography).
Brief overview about important developments:
Imaging used for medical purposes, began after the discovery of x-rays by Konrad Roentgen 1896. The first fifty years of radiological imaging, pictures have been created by focusing x-rays on the examined body part and direct depiction onto a single piece of film inside a special cassette.
In the 1950s, first nuclear medicine studies showed the up-take of very low-level radioactive chemicals in organs, using special gamma cameras. This diagnostic imaging technology allows information of biologic processes in vivo. Today, single photon emission computed tomography (SPECT) and positron emission tomography (PET) play an important role in both clinical research and diagnosis of biochemical and physiologic processes.
In the 1960s, the principals of sonar were applied to diagnostic imaging. Ultrasound has been imported into practically every area of medicine as an important diagnostic tool, and there are great opportunities for its further development. Looking into the future, the grand challenges include targeted contrast imaging, real-time 3D or 4D ultrasound, and molecular imaging. The earliest use of ultrasound contrast agents (USCA) was in 1968.
The introduction of computed tomography (CT/CAT) in the 1970s revolutionized medical imaging with cross sectional images of the human body and high contrast between different types of soft tissues. These developments were made possible by analog to digital converters and computers. First, spiral CT (also called helical), then multislice CT (or multi-detector row CT) technology expanded the clinical applications dramatically.
The first magnetic resonance imaging (MRI) devices were tested on clinical patients in 1980. With technological improvements including higher field strength, more open MRI magnets, faster gradient systems, and novel data-acquisition techniques, MRI is a real-time interactive imaging modality that provides both detailed structural and functional information of the body.

Today, imaging in medicine has been developed to a stage that was inconceivable a century ago, with growing modalities:
x-ray projection imaging, including conventional radiography and digital radiography;
scintigraphy;
single photon emission computed tomography;
positron emission tomography.

All these types of scans are an integral part of modern healthcare. Usually, a radiologist interprets the images. Most clinical studies are acquired by a radiographer or radiologic technologist. In filmless, digital radiology departments all images are acquired and stored on computers. Because of the rapid development of digital imaging modalities, the increasing need for an efficient management leads to the widening of radiology information systems (RIS) and archival of images in digital form in a picture archiving and communication system (PACS). In telemedicine, medical images of MRI scans, x-ray examinations, CT scans and ultrasound pictures are transmitted in real time.

See also Interventional Radiology, Image Quality and CT Scanner.
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