Fluoroscopy in the context of 4DCT

Digital imaging or digital image acquisition is the creation of a digital representation of the visual characteristics of an object, such as a physical scene or the interior structure of an object. The term is often assumed to imply or include the processing, compression, storage, printing and display of such images. A key advantage of a digital image, versus an analog image such as a film photograph, is the ability to digitally propagate copies of the original subject indefinitely without any loss of image quality.

Digital imaging can be classified by the type of electromagnetic radiation or other waves whose variable attenuation, as they pass through or reflect off objects, conveys the information that constitutes the image. In all classes of digital imaging, the information is converted by image sensors into digital signals that are processed by a computer and made output as a visible-light image. For example, the medium of visible light allows digital photography (including digital videography) with various kinds of digital cameras (including digital video cameras). X-rays allow digital X-ray imaging (digital radiography, fluoroscopy, and CT), and gamma rays allow digital gamma ray imaging (digital scintigraphy, SPECT, and PET). Sound allows ultrasonography (such as medical ultrasonography) and sonar, and radio waves allow radar. Digital imaging lends itself well to image analysis by software, as well as to image editing (including image manipulation).

Flat-panel detectors are a class of solid-state x-ray digital radiography devices similar in principle to the image sensors used in digital photography and video. They are used in both projectional radiography and as an alternative to x-ray image intensifiers (IIs) in fluoroscopy equipment.

Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by X-ray radiation. It is important to note that projectional radiography is not the same as a radiographic projection, which refers specifically to the direction of the X-ray beam and patient positioning during the imaging process. The image acquisition is generally performed by radiographers, and the images are often examined by radiologists. Both the procedure and any resultant images are often simply called 'X-ray'. Plain radiography or roentgenography generally refers to projectional radiography (without the use of more advanced techniques such as computed tomography that can generate 3D-images). Plain radiography can also refer to radiography without a radiocontrast agent or radiography that generates single static images, as contrasted to fluoroscopy, which are technically also projectional.

An X-ray image intensifier (XRII) is an image intensifier that converts X-rays into visible light at higher intensity than the more traditional fluorescent screens can. Such intensifiers are used in X-ray imaging systems (such as fluoroscopes) to allow low-intensity X-rays to be converted to a conveniently bright visible light output. The device contains a low absorbency/scatter input window, typically aluminum, input fluorescent screen, photocathode, electron optics, output fluorescent screen and output window. These parts are all mounted in a high vacuum environment within glass or, more recently, metal/ceramic. By its intensifying effect, It allows the viewer to more easily see the structure of the object being imaged than fluorescent screens alone, whose images are dim. The XRII requires lower absorbed doses due to more efficient conversion of X-ray quanta to visible light. This device was originally introduced in 1948.

Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions across secretory and epithelial cells, and regulating cell volume. Ion channels are present in the membranes of all cells. Ion channels are one of the two classes of ionophoric proteins, the other being ion transporters.

The study of ion channels often involves biophysics, electrophysiology, and pharmacology, while using techniques including voltage clamp, patch clamp, immunohistochemistry, X-ray crystallography, fluoroscopy, and RT-PCR. Their classification as molecules is referred to as channelomics.

Industrial radiography is a modality of non-destructive testing that uses ionizing radiation to inspect materials and components with the objective of locating and quantifying defects and degradation in material properties that would lead to the failure of engineering structures. It plays an important role in the science and technology needed to ensure product quality and reliability. In Australia, industrial radiographic non-destructive testing is colloquially referred to as "bombing" a component with a "bomb".

Industrial Radiography uses either X-rays, produced with X-ray generators, or gamma rays generated by the natural radioactivity of sealed radionuclide sources. Neutrons can also be used. After crossing the specimen, photons are captured by a detector, such as a silver halide film, a phosphor plate, flat panel detector or CdTe detector. The examination can be performed in static 2D (named radiography), in real time 2D (fluoroscopy), or in 3D after image reconstruction (computed tomography or CT). It is also possible to perform tomography nearly in real time (4-dimensional computed tomography or 4DCT). Particular techniques such as X-ray fluorescence (XRF), X-ray diffractometry (XRD), and several other ones complete the range of tools that can be used in industrial radiography.

Radiology (/ˌreɪdiˈɒlədʒi/ RAY-dee-AHL-ə-jee) is the medical specialty that uses medical imaging to diagnose diseases and guide treatment within the bodies of humans and other animals. It began with radiography (which is why its name has a root referring to radiation), but today it includes all imaging modalities. This includes technologies that use no ionizing electromagnetic radiation, such as ultrasonography and magnetic resonance imaging (MRI), as well as others that do use radiation, such as computed tomography (CT), fluoroscopy, and nuclear medicine including positron emission tomography (PET). Interventional radiology is the performance of usually minimally invasive medical procedures with the guidance of imaging technologies such as those mentioned above.

The modern practice of radiology involves a team of several different healthcare professionals. A radiologist, who is a medical doctor with specialized post-graduate training, interprets medical images, communicates these findings to other physicians through reports or verbal communication, and uses imaging to perform minimally invasive medical procedures The nurse is involved in the care of patients before and after imaging or procedures, including administration of medications, monitoring of vital signs and monitoring of sedated patients. The radiographer, also known as a radiologic technologist in countries such as the United States and Canada, is a specialized healthcare professional who performs radiographic procedures and radiation therapy for the diagnosis and treatment of diseases such as cancer. The images produced through radiographic procedures are used for interpretation by radiologists, and depending on their education, training, and the regulations of the country in which they practice, radiographers in some regions also have an extended role in image interpretation and reporting.

Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement (e.g., stents), and angioplasty of narrowed structures.

The main benefits of IR techniques are that they can reach the deep structures of the body through a body orifice or tiny incision using small needles and wires. This decreases risks, pain, and recovery compared to open procedures. Real-time visualization also allows precision guidance to the abnormality, making the procedure or diagnosis more accurate. These benefits are weighed against the additional risks of lack of immediate access to internal structures (should bleeding or a perforation occur), and the risks of radiation exposure such as cataracts and cancer.

Spinal fusion, also called spondylodesis or spondylosyndesis, is a surgery performed by orthopaedic surgeons or neurosurgeons that joins two or more vertebrae. This procedure can be performed at any level in the spine (cervical, thoracic, lumbar, or sacral) and prevents any movement between the fused vertebrae. There are many types of spinal fusion and each technique involves using bone grafting—either from the patient (autograft), donor (allograft), or artificial bone substitutes—to help the bones heal together. Additional hardware (screws, plates, or cages) is often used to hold the bones in place while the graft fuses the two vertebrae together. The placement of hardware can be guided by fluoroscopy, navigation systems, or robotics.

Spinal fusion is most commonly performed to relieve the pain and pressure from mechanical pain of the vertebrae or on the spinal cord that results when a disc (cartilage between two vertebrae) wears out (degenerative disc disease). It is also used as a backup procedure for total disc replacement surgery (intervertebral disc arthroplasty), in case patient anatomy prevents replacement of the disc. Other common pathological conditions that are treated by spinal fusion include spinal stenosis, spondylolisthesis, spondylosis, spinal fractures, scoliosis, and kyphosis.

Interventional cardiology is a branch of cardiology that deals specifically with the catheter based treatment of structural heart diseases. Andreas Gruentzig is considered the father of interventional cardiology after the development of angioplasty by interventional radiologist Charles Dotter.

Many procedures can be performed on the heart by catheterization. This most commonly involves the insertion of a sheath into the femoral artery (but, in practice, any large peripheral artery or vein) and cannulating the heart under X-ray visualization (most commonly fluoroscopy). The radial artery may also be used for cannulation; this approach offers several advantages, including the accessibility of the artery in most patients, the easy control of bleeding even in anticoagulated patients, the enhancement of comfort because patients are capable of sitting up and walking immediately following the procedure, and the near absence of clinically significant sequelae in patients with a normal Allen test. Downsides to this approach include spasm of the artery and pain, inability to use larger catheters needed in some procedures, and more radiation exposure. But, in recent times radial approach is getting popularity due to its patient comfort after procedure.

Radiocontrast agents are substances used to enhance the visibility of internal structures in X-ray-based imaging techniques such as computed tomography (contrast CT), projectional radiography, and fluoroscopy. Radiocontrast agents are typically iodine, or more rarely barium sulfate. The contrast agents absorb external X-rays, resulting in decreased exposure on the X-ray detector. This is different from radiopharmaceuticals used in nuclear medicine which emit radiation.

Magnetic resonance imaging (MRI) functions through different principles and thus MRI contrast agents have a different mode of action. These compounds work by altering the magnetic properties of nearby hydrogen nuclei.