Nowadays, in all forms of digital X-ray imaging (radiography, fluoroscopy, and CT) the conversion of X-ray energy into visible light can be achieved by the same types of electronic sensors, such as flat panel detectors, which convert the X-ray energy into electrical signals, small bursts of current that convey information that a computer can analyze, store, and output as images. After the development of X-ray image intensifiers, the images were bright enough to see without goggles under normal ambient light. While much of the energy given to the electrons is dissipated as heat, a fraction of it is given off as visible light.Įarly radiologists would adapt their eyes to view the dim fluoroscopic images by sitting in darkened rooms, or by wearing red adaptation goggles. Images on the screen are produced as the unattenuated or mildly attenuated X-rays from radiolucent tissues interact with atoms in the screen through the photoelectric effect, giving their energy to the electrons. This use of fluorescent materials to make a viewing scope is how fluoroscopy got its name.Īs the X-rays pass through the patient, they are attenuated by varying amounts as they pass through or reflect off the different tissues of the body, casting an X-ray shadow of the radiopaque tissues (such as bone tissue) on the fluorescent screen. ![]() Classic film-based radiography achieves this by the variable chemical changes that the X-rays induce in the film, and classic fluoroscopy achieves it by fluorescence, in which certain materials convert X-ray energy (or other parts of the spectrum) into visible light. To take advantage of the penetration for image-forming purposes, one must somehow convert the X-rays' intensity variations (which correspond to material contrast and thus image contrast) into a form that is visible. In contrast, X-rays can penetrate a wider variety of objects (such as the human body), but they are invisible to the naked eye. Visible light can be seen by the naked eye (and thus forms images that people can look at), but it does not penetrate most objects (only translucent ones). However, today radiography, CT, and fluoroscopy are all digital imaging modes with image analysis software and data storage and retrieval. The original difference was that radiography fixed still images on film whereas fluoroscopy provided live moving pictures that were not stored. For many decades, fluoroscopy tended to produce live pictures that were not recorded, but since the 1960s, as technology improved, recording and playback became the norm.įluoroscopy is similar to radiography and X-ray computed tomography (X-ray CT) in that it generates images using X-rays. ![]() However, since the 1950s most fluoroscopes have included X-ray image intensifiers and cameras as well, to improve the image's visibility and make it available on a remote display screen. In its simplest form, a fluoroscope consists of an X-ray source and a fluorescent screen, between which a patient is placed. This is useful for both diagnosis and therapy and occurs in general radiology, interventional radiology, and image-guided surgery. In its primary application of medical imaging, a fluoroscope ( / ˈ f l ʊər ə s k oʊ p/) allows a physician to see the internal structure and function of a patient, so that the pumping action of the heart or the motion of swallowing, for example, can be watched. Fluoroscopy ( / f l ʊəˈr ɒ s k ə p i/ ) is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object.
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