Articles
Articles are a collaborative effort to provide a single canonical page on all topics relevant to the practice of radiology. As such, articles are written and continuously improved upon by countless contributing members. Our dedicated editors oversee each edit for accuracy and style. Find out more about articles.
716 results found
Article
Flat panel detector
Flat panel detector (FPD) is the most common detector type used in direct digital radiography (DR). The x-rays are converted to electrical charges, either directly or indirectly (x-rays first converted to visible light, then to charges). The charges are then read out using a thin film transistor...
Article
Shear wave elastography
Shear wave elastography is a developing variation of ultrasound imaging.
The concept is similar to strain elastography, but instead of using transducer pressure to compare a shift in an ultrasound A-line (thereby measuring changes in strain), a higher intensity pulse is transmitted to produce s...
Article
Wilhelm Roentgen
Wilhelm C Roentgen (1845-1923) was a German physicist who is celebrated globally for his discovery of x-rays on 8 November 1895.
Early life
Wilhelm Conrad Roentgen (Röntgen in German) was born on 27 March 1845 in Lennep, Germany. He attended the primary and secondary school run by Martinus Her...
Article
Factors affecting T1
Factors affecting T1 and T2 relaxation times of different tissues are generally based on molecular motion, size and interactions.
The protons giving rise to an NMR signal are mainly those in cell water and lipids (i.e. protons that are free to move), while those in protein and solids usually do...
Article
Adrenal glands ultrasound
Adrenal glands ultrasound, is an imaging method that can provide valuable information regarding their size, shape, and structure. As a result, it can aid in diagnosing various pathological conditions related to adrenal gland function.
Techniques
Several ultrasound techniques can be employed to...
Article
Nuclear medicine
Nuclear medicine in vivo is the practice of utilizing small amounts of radioactive substances (unsealed radioactive sources) to diagnose, monitor and treat disease. The utilization of radiopharmaceuticals (radionuclide + pharmaceutical) offers a unique perspective on both disease and cancer trea...
Article
Lead equivalent personal protection equipment
Lead equivalent personal protection equipment (PPE) should be available in all radiology departments and operating suites. There are three traditional principles for ionizing radiation safety: time, distance, and shielding. It is important to remember that all three principles have a part to pla...
Article
Enteric contrast medium (CT)
Enteric contrast media can be given to patients before their CT exam to improve its diagnostic accuracy. Historically, a combination of oral and intravenous contrast media were always given prior to a CT abdomen. Contemporaneously, improved CT scanners mean that oral contrast agents are no longe...
Article
Tube arcing
Tube arcing occurs when there is a short-circuit within the tube, typically from the cathode to the tube envelope. The result is a temporary loss of x-ray output and a localized artifact.
A number of causes of tube arcing are recognized 1:
insulator surface flashover
insulator breakdow...
Article
Brown adipose tissue
Brown adipose tissue (BAT) (also known as brown fat) is one of two types of adipose tissue (the other one being white fat) important for producing thermal energy (heat, non-shivering thermogenesis), especially in the newborn. It constitutes ~5% of body mass in the newborn and tends to reduce mar...
Article
X-ray tube
An x-ray tube functions as a specific energy converter, receiving electrical energy and converting it into two other forms of energy: x-radiation (1%) and heat (99%). Heat is considered the undesirable product of this conversion process; therefore x-radiation is created by taking the energy from...
Article
Contrast-enhanced voiding urosonography
Contrast-enhanced voiding urosonography (occasionally abbreviated as ce-VUS) is a relatively novel contrast-enhanced ultrasonographic technique utilizing microbubbles to detect vesicoureteral reflux.
Indications
Suspected or confirmed vesicoureteral reflux is the primary indication for contra...
Article
Cone beam effect
Cone beam effect artifacts are seen in multidetector row CT (cone beam CT) acquisitions 1. Modern CT scanners use more detector arrays to increase the number of sections acquired per rotation. This causes the x-ray beams to become cone-shaped as opposed to fan-shaped 2. As a result instead of co...
Article
Mass attenuation coefficient
The mass attenuation coefficient (also known as the mass absorption coefficient) is a constant describing the fraction of photons removed from a monochromatic x-ray beam by a homogeneous absorber per unit mass.
It is equivalent to the linear attenuation coefficient divided by the density of the...
Article
O-arm
The O-arm is a movable CT imaging structure developed for intraoperative 3D fluoroscopic imaging. It is utilized during surgery for the identification of bony details in complex procedures such as spinal fixation or microdiscectomy.
See also
C-arm
Article
Virtual reality
Advancements of technology have enabled various simulated reality devices, including virtual reality (VR) and augmented reality (AR). Both technologies provide stereoscopic and three-dimensional (3D) immersion of a simulated object. VR simulates a virtual environment while AR overlays simulated ...
Article
Linear energy transfer
Linear energy transfer (LET) is the average (radiation) energy deposited per unit path length along the track of an ionizing particle. Its units are keV/μm.
Linear energy transfer describes the energy deposition density of a particular type of radiation, which largely determines the biological ...
Article
Tesla (SI unit)
The tesla (symbol T) is the derived SI unit of magnetic flux density, which represents the strength of a magnetic field. One tesla represents one weber per square meter. The equivalent, and superseded, cgs unit is the gauss (G); one tesla equals exactly 10,000 gauss.
Medical magnetic resonance ...
Article
Emerging medical imaging technologies
This article is a summary of emerging medical imaging technologies in development or in the early phase of clinical adoption. The methods are listed by modality.
Radiography
dark-field radiography
x-ray phase-contrast imaging
CT
dark-field CT
deep-learning reconstruction
photon counting ...
Article
CT neck (protocol)
The CT neck protocol serves as a radiological examination of the head and neck. This protocol is usually performed as a contrast study and might be acquired separately or combined with a CT chest or CT chest-abdomen-pelvis. On rare occasions, it will be performed as a non-contrast study. Dependi...
Unable to process the form. Check for errors and try again.