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 edited by countless contributing members over a period of time. A global group of dedicated editors oversee accuracy, consulting with expert advisers, and constantly reviewing additions.

635 results found
Article

MRI pulse sequences

An MRI pulse sequence is a programmed set of changing magnetic gradients. Each sequence will have a number of parameters, and multiple sequences grouped together into an MRI protocol.  Parameters A pulse sequence is generally defined by multiple parameters, including: time to echo (TE) time ...
Article

MRI safety

MRI scanners, although free from potentially cancer-inducing ionizing radiation found in plain radiography and CT, have a host of safety issues which must be taken very seriously. MRI safety can be divided into: main magnetic field varying magnetic (gradient) fields radiofrequency Main magne...
Article

MRI sequence parameters

Listed in the table below are the most common acquisition parameters for commonly used MRI pulse sequences (in msec). For a general introduction to these sequences please refer to MRI sequences (basic). The specific parameters for any given study varies from one manufacturer to another, and fr...
Article

MRI sequences (overview)

An MRI sequence is a number of radiofrequency pulses and gradients that result in a set of images with a particular appearance. This article presents a simplified approach to recognizing common MRI sequences, but does not concern itself with the particulars of each sequence. For a more complete...
Article

MR liver iron quantification

MR liver iron quantification is a non-invasive means of measuring liver iron concentration, a key indicator in the management of patients with hemochromatosis (primary or secondary). Advantages Apart from being non-invasive, sampling occurs in a large cross-section of the liver, as opposed to ...
Article

MR perfusion weighted imaging

Perfusion weighted imaging is a term used to denote a variety of MRI techniques able to give insights into the perfusion of tissues by blood.  There are three techniques in wide use to derive one or more perfusion values:  ​techniques ​dynamic susceptibility contrast (DSC) MR perfusion dynam...
Article

MR spectroscopy

The technique of magnetic resonance spectroscopy (usually shortened to MR spectroscopy or MRS) allows tissue to be interrogated for the presence and concentration of various metabolites. Grossman and Yousem said "If you need this to help you, go back to page 1; everything except Canavan (disease...
Article

MR tagging

Cardiac MR tagging or myocardial tagging refers to a MRI based acquisition method designed for myocardial deformation analysis. Methodology The method exploits tissue magnetization as a tissue property. A local magnetic saturation grid of dark lined tissue markers known as tags are induced ont...
Article

MR vessel wall imaging

MR vessel wall imaging refers to MRI techniques used to evaluate for disease within the walls of arteries, beyond the luminal abnormalities depicted on angiographic imaging. This can be used anywhere in the body but is particularly important intracranially in distinguishing between various cause...
Article

Multipath artifact

A multipath artefact is an ultrasound beam artefact in which the primary beam reflects off anatomy at an angle, resulting in a portion of the beam returning to the transducer, whilst another portion takes a longer duration as it reflects a second structure. This phenomenon results in a propagati...
Article

Multiplanar reformation (MPR)

Multiplanar reformation or reconstruction (MPR) involves the process of converting data from an imaging modality acquired in a certain plane, usually axial, into another plane 1. It is most commonly performed with thin-slice data from volumetric CT in the axial plane, but it may be accomplished ...
Article

Myocardial mapping

Myocardial mapping or parametric mapping of the heart is one of various magnetic resonance imaging techniques, which has evolved and been increasingly used in the last decade for non-invasive tissue characterization of the myocardium 1-5. Unlike normal T1-, T2- or T2*- images, parametric mapping...
Article

Myo-inositol peak

Myo-inositol is one of the compounds images with MR spectroscopy (MRS) at both 1.5 T and 3 T and is seen to resonate at 3.5 ppm chemical shift (right of the choline peak).  Myo-inositol is a precursor of both phosphatidylinositol (the major inositol-containing phospholipid) and phosphatidylinos...
Article

N-acetylaspartate (NAA) peak

N-acetylaspartate (NAA) is one of the more important compounds assessed on MR spectroscopy, and resonates at 2.0 ppm chemical shift (its concentration in healthy adults is 8-10 mM) 1. The synthesis of NAA, adenosine diphosphate-dependent, occurs in the neuronal mitochondria 2. NAA is the acetyl...
Article

Negative enhancement integral

The negative enhancement integral in MR perfusion is used to calculate the relative cerebral blood volume (rCBV).  It represents the area described by the baseline and the signal loss due to passage of contrast bolus in tissue. 
Article

Nephrogenic systemic fibrosis

Nephrogenic systemic fibrosis (NSF), also known as nephrogenic fibrosing dermopathy, is a complication of gadolinium-based contrast agents used in MRI. It is characterized by "firm, erythematous, and indurated plaques of the skin associated with subcutaneous edema" 1. Eventually, flexure contra...
Article

Neutron therapy

Neutron therapy is a form of particle therapy using neutrons as the energy-carrying particle. The therapy has shown promise for some malignancies but there have also been problems with accurate dose distributions and late complications. Some of these problems historically were thought to be - at...
Article

NIfTI (file format)

NIfTI is a type of file format for neuroimaging. Technically there are NIfTI-1 and NIfTI-2 file formats. The NIfTI-2 format is an update on NIfTI-1 that allows more data to be stored. NIfTI files are used very commonly in imaging informatics for neuroscience and even neuroradiology research. In ...
Article

Nobel Prizes for radiology

The Nobel Prizes have been awarded since 1901, and several have been won for scientific discoveries with a direct or indirect importance for the development of radiology.  History The Nobel Prizes were originally established in the will of Alfred Nobel (1833-1896), a very wealthy Swedish weapo...
Article

Noise

Noise, information that is not part of a desired signal, is present in all electronic systems, and originates from a number of sources including electronic interference. It appears as an irregular granular pattern in all images and degrades image information. It may be inapparent or render image...
Article

Noise reduction

Noise reduction, also known as noise suppression or denoising, commonly refers to the various algorithmic techniques to reduce noise in digital images once they are created although a few sources use the term more broadly to imply anything that reduces noise. In digital image processing various ...
Article

Non contrast enhanced MR angiography

Non contrast enhanced MR angiography is performed in several ways including: time of flight angiography phase contrast angiography three-dimensional (3D) electrocardiograph-triggered half-Fourier fast spin echo Generally, these techniques are time-consuming as compared with contrast enhanced...
Article

Nuclear magnetic resonance

Nuclear magnetic resonance (NMR) is a powerful technique which allows the study of the magnetic properties of an atom's nucleus 1. It involves placing nuclei within an external magnetic field enabling thus them to undergo precession 2. The 'resonance' part of the names implies the fact that a se...
Article

Nuclear magnetization

Nuclear magnetization refers to the magnetic moment of an atomic nucleus. Magnetic resonance imaging (MRI) makes use of nuclear magnetic resonance (NMR). Some nuclei may have nuclear magnetization depending on their nuclear charge distribution and the spin of their protons and neutrons. Nuclei w...
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 offers a unique perspective on both disease and cancer treatment.
Article

Nuclear shell model

The nuclear shell model is a theoretical construct in nuclear physics which describes that the nucleus of an atom can exist in discrete energy states. This model is partially analogous to the electron orbitals of the atomic shell model. The ground state is the lowest energy state for a specific...
Article

Nuclide

A nuclide is a nuclear-centric term, describing an atomic species by its nuclear composition and nuclear energy state. A nuclide has a specific number of protons and neutrons, and will additionally have a specific energy state of its nucleus. Radionuclides are unstable nuclides that undergo ra...
Article

Nyquist limit

The Nyquist limit represents the maximum Doppler shift frequency that can be correctly measured without resulting in aliasing in color or pulsed wave ultrasound.  Physics The Nyquist limit always equals Pulse Repetition Frequency (PRF)/2. The US machine can display the Nyquist limit either as ...
Article

Octreotide scintigraphy

Octreotide scintigraphy uses 111In-labeled octreotide which is a somatostatin analog; it is also known as an OctreoscanTM, a brand name for 111In-labeled pentetreotide; pentetreotide is a DTPA-conjugated form of octreotide, originally manufactured by Mallinckrodt Nuclear Medicine LLC, which now ...
Article

Off focus radiation

During x-ray generation, off-focus radiation refers to the emission of x-ray photons which originate outside of the anode focal spot. Essentially a form of scatter, photons produced in this manner may result in blurring and are of no use for diagnostic purposes. They are shielded as much as poss...
Article

Ontology

Ontology is the study of the nature of being, existence or reality as such, as well as the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology deals with questions concerning what entities exist or can be ...
Article

Output phosphor

The output phosphor is a component of the image intensifier in fluoroscopic systems that converts the energy from the electrons into light photons. In an II, the large number of light photons produced are subsequently captured by various imaging devices to produce a visible image. Composition  ...
Article

Pair production

Pair production (PP), like the photoelectric effect, results in the complete attenuation of the incident photon. Pair production can only occur if the incident photon energy is at least 1.022 MeV. As the photon interacts with the strong electric field around the nucleus it undergoes a change of ...
Article

Paramagnetism

Paramagnetic materials include oxygen and ions of various metals like Fe (iron), Mg (magnesium), and Gd (gadolinium). These ions have unpaired electrons, resulting in a positive magnetic susceptibility. The magnitude of this susceptibility is less than 0.1% of that of ferromagnetic materials. T...
Article

Parathyroid 4D CT

Parathyroid four-dimensional (4D) CT refers to multiphase computed tomography of the neck used to localize abnormal parathyroid glands (i.e., involved with adenoma, hyperplasia, or, rarely, carcinoma). The "4D" indicates that imaging is performed in multiple phases of contrast, with time being t...
Article

Partial volume averaging (CT artifact)

Partial volume artifact occurs when tissues of widely different absorption are encompassed on the same CT voxel producing a beam attenuation proportional to the average value of these tissues.  The latest generation of CT scanners with an associated reduction in the volume of a voxel has substa...
Article

Particle therapy

Particle therapy (also known as hadronic therapy) is the generic term used for any type of external beam radiotherapy (EBRT) employing high-energy particles. Currently proton therapy accounts for most of this type of EBRT. Although strictly a form of particle therapy, electron therapy is usually...
Article

Paul Lauterbur

Paul C Lauterbur (1929-2007) is remembered as one of the co-developers of MRI, for which he was co-awarded the Nobel Prize for Medicine or Physiology in 2003, with Peter Mansfield. Early life Paul Christian Lauterbur was born on 6 May 1929 in Sidney, Ohio.In 1951 he graduated with a bachelor o...
Article

PD weighted spin-echo images

Proton-density weighted images are related to the number of nuclei in the area being imaged (number of hydrogen protons), as opposed to the magnetic characteristics of the hydrogen nuclei. They are produced from the first echo. PD weighted images result when the contribution of both T1 and T2 co...
Article

Peak systolic velocity (Doppler ultrasound)

Peak systolic velocity (PSV) is an index measured in spectral Doppler ultrasound. On a Doppler waveform, the peak systolic velocity corresponds to each tall “peak” in the spectrum window 1. Explanation When traveling with their greatest velocity in a vessel (i.e. during systole), red blood cel...
Article

Pelvic cervical carcinoma protocol (MRI)

A dedicated pelvic MRI protocol is very useful for imaging assessment of cervical carcinoma. Although the FIGO is a clinical staging, the 2009 revised FIGO staging encourages the use of MRI to complement clinical staging. Preparation Imaging is optimally performed after three hours of fasting...
Article

Peter Mansfield

Sir Peter Mansfield (1933-2017) was an English physicist best known for his research into, and development of MRI, for which he was awarded the Nobel Prize in Physiology or Medicine in 2003 1. Early life Peter Mansfield was born on the 9 October, 1933 in Lambeth, London. His father, Sidney wor...
Article

PET radiotracers

A PET radiotracer (also known as PET tracer) is a positron-emitting radiopharmaceutical used in positron emission tomography (PET). Each tracer consists of a positron-emitting isotope (radioactive tag) bound to an organic ligand (targeting agent). The ligand component of each tracer interacts wi...
Article

Phase contrast imaging

Phase contrast imaging is an MRI technique that can be used to visualize moving fluid. Basic principle Spins that are moving in the same direction as a magnetic field gradient develop a phase shift that is proportional to the velocity of the spins. This is the basis of phase-contrast angiograp...
Article

Phased array

A phased array ultrasound transducer is typically 2-3 cm long, consisting of 64-128 elements. It is a smaller assembly than a sequential array and can be either linear or curvilinear. A sector field of view is produced by all elements firing to create a single waveform. Small delays in element ...
Article

Phased array coil

Phased array coils are an example of a receive-only radiofrequency coil system which receives the radiofrequency signal in MRI. It involves the collection of multiple surface coils into a larger array whose individual signals are combined to create one image. As signal coils detect signal based ...
Article

Phase-encoded motion artifact

Phase-encoded motion artifact is one of many MRI artifacts occurring as a result of tissue/fluid moving during the scan. It manifests as ghosting in the direction of phase-encoding, usually in the direction of the short axis of the image (i.e left to right on axial or coronal brains, and anterio...
Article

Photocathode

A photocathode is a negatively charged electrode in a light detection device such as the input screen in an image intensifier (II) that is coated with a photosensitive compound. When this is struck by light photons, the absorbed energy causes electron emission due to the photoelectric (PE) effec...
Article

Photoelectric effect

Photoelectric effect or photoelectric absorption is one of the principal forms of interaction of x-ray and gamma photons with matter. A photon interacts with an inner shell electron in the atom and removes it from its shell. Probability of photoelectric effect The probability of this effect is...
Article

Photoluminescence

Photoluminescence is a property of a material to absorb, store and convert photons to light. Photoluminescent materials have important applications in radiology. Types Fluorescence is the instantaneous emission of light following photon absorption. It typically occurs within 10-8 seconds. Exa...
Article

Photomultiplier tube (Gamma camera)

The photomultiplier tube array of a Gamma camera detects the visible light produced by the scintillator, and converts it to a measurable electronic signal. A series of photomultiplier tubes are mounted behind the scintillation crystal. Each photomultiplier tube is composed of a tightly sealed,...
Article

Photon

A photon is, in simple terms, an elementary force-carrying particle i.e. a boson 2 (obeys the statistical law of Bose-Einstein). It has a zero mass (rest mass) and travels at, c, the speed of light in vacuo. It is defined as stable with no electric charge and exhibits both wave-like and particle...
Article

Photon-counting computed tomography

Photon-counting computed tomography (PCCT) is an emerging technology in CT imaging, which could represent the next major technological milestone in the field. Briefly, PCCT uses energy-resolving detectors, thereby enabling scanning at multiple energies. Physics Current clinical CT systems rely...
Article

Photon starvation

Photon starvation is one source of streak artifact which may occur in CT. It is seen in high attenuation areas, particularly behind metal implants. Because of high attenuation, insufficient photons reach the detector. During the reconstruction process, the noise is greatly magnified in these are...
Article

Photopeak

The photopeak refers to the region of the pulse height spectrum caused by the complete photoelectric absorption of Gamma rays by the scintillator crystal of a Gamma camera. The energy value of the photopeak(s) should correspond to the characteristic energies of the Gamma rays emitted by the rad...
Article

Photostimulable phosphors

Photostimulable phosphors (PSP) are materials that store absorbed energy within excited electrons and release it in the form of light on exposure to laser energy. The process can be broken up as follows 1: an x-ray or gamma photon interacts with the PSP and releases high energy secondary elect...
Article

Physical principles of ultrasound

Medical ultrasound is based on the use of high-frequency sound to aid in the diagnosis and treatment of patients. Ultrasound frequencies range from 2 to approximately 15 MHz, although even higher frequencies may be used in some situations. The ultrasound beam originates from mechanical oscillat...
Article

Physics and imaging technology: CT

Knowledge of the physics and imaging technology involved in the production of CT scans is vitally important for medical imaging specialists. See also physics and imaging technology: x-ray physics and imaging technology: ultrasound physics and imaging technology: CT physics and imaging techn...
Article

Physics and imaging technology: MRI

Knowledge of the physics and imaging technology involved in the production of MRI scans is vitally important for medical imaging specialists. See also physics and imaging technology: x-ray physics and imaging technology: ultrasound physics and imaging technology: CT physics and imaging tech...
Article

Physics and imaging technology: nuclear medicine

Knowledge of the physics and imaging technology involved in the production of nuclear medicine scans is vitally important for medical imaging specialists. See also physics and imaging technology: x-ray physics and imaging technology: ultrasound physics and imaging technology: CT physics and...
Article

Physics and imaging technology: ultrasound

Knowledge of the physics and imaging technology involved in the production of ultrasound (US) scans is vitally important for medical imaging specialists. See also physics and imaging technology: x-ray physics and imaging technology: ultrasound physics and imaging technology: CT physics and ...
Article

Physics and imaging technology: x-ray

Knowledge of the physics and imaging technology involved in the production of x-rays is vitally important for medical imaging specialists. See also physics and imaging technology: x-ray physics and imaging technology: ultrasound physics and imaging technology: CT physics and imaging technol...
Article

Physics curriculum

The physics curriculum is one of our curriculum articles and aims to be a collection of articles that represent core physics and imaging technology knowledge: physics and imaging technology: x-ray physics and imaging technology: ultrasound physics and imaging technology: CT physics and imagi...
Article

Picture archiving and communication system

Picture archiving and communication system (PACS) is a modality of imaging technology which helps in image transmission from the site of image acquisition to multiple physically-disparate locations. This technology not only is economical (film-less department), but also convenient to access mult...
Article

Pierre Curie

Pierre Curie (1859–1906) was a French physicist who was co-awarded the Nobel Prize for Physics in 1903, with his wife Marie Curie, and Henri Becquerel, for their pioneering work on radioactivity, which included the joint discovery with his wife of radium and polonium. He also discovered piezoele...
Article

Piezoelectric effect

The piezoelectric effect converts kinetic or mechanical energy, due to crystal deformation, into electrical energy. This is how ultrasound transducers receive the sound waves. The same effect can be used in reverse – inverse piezoelectric effect – whereby the application of an electric field to...
Article

Pion therapy

Pion therapy is a form of particle therapy employing pions. Pions, or to give them their full name, negatively-charged pi mesons (π-), are a type of meson. Pion therapy is currently not used as a treatment modality due to its great expense and lack of clinical efficacy 1,2.
Article

Pitch (CT)

Pitch (P) is a term used in helical CT. It has two terminologies depending on whether single slice or multislice CT scanners are used 1-3. Single slice CT (SSCT) The term detector pitch is used and is defined as table distance traveled in one 360° gantry rotation divided by beam collimation 2....
Article

Pixel

A pixel (or pel or picture element) may refer to either the smallest discrete element of the physical display or to the smallest element of the image. Voxel is its 3-dimensional equivalent, as employed in CT and other cross-sectional imaging modalities. History and etymology The history of the...
Article

Pixel shift (reregistration)

Pixel shift or reregistration is a post-processing technique used to improve misregistration artifact in digital subtraction angiography, where two images to be subtracted are spatially realigned with respect to one another, by shifting pixels vertically, horizontally or obliquely.  Pixel shift...
Article

Portosystemic shunt ratio

The portosystemic shunt ratio is a measure performed using ultrasound to quantify the abnormal flow of portal venous blood that is shunted away from the hepatic sinusoidal circulation in the context of a congenital portosystemic shunt 1. Measurement The ratio is determined on ultrasound using ...
Article

Positron emission tomography

Positron emission tomography (PET) is a modern non-invasive imaging technique for quantification of radioactivity in vivo. It involves the intravenous injection of a positron-emitting radiopharmaceutical, waiting to allow for systemic distribution, and then scanning for detection and quantificat...
Article

Power Doppler

Power Doppler is a technique that uses the amplitude of Doppler signal to detect moving matter. Power Doppler: is independent of velocity and direction of flow, so there is no possibility of signal aliasing is independent of angle, allowing detection of smaller velocities than color Doppler, f...
Article

Production of radioactive nuclei

Naturally occurring radioactive nuclei have a physical half life time of ~108 to 1010 years which makes them unsuitable for use in medical imaging. Thus radioactive nuclei used in medical practice are artificially synthesized. Production of these nuclei involve bombarding stable nuclei with pro...
Article

Propagation speed

The propagation speed of sound waves through tissue is an important element of ultrasound scans. Ultrasound machines assume sound waves travel at a speed of 1540 m/sec through tissue 1. In reality, the speed of sound is affected by the density and elasticity of the medium through which it is tr...
Article

Prostate MRI protocol

Prostate MRI has become an increasingly frequent examination faced in daily radiological practice and is usually acquired as either multiparametric or biparametric MRI of the prostate. Note: This article aims to outline the concept of an MRI protocol for the assessment of the prostate. Recomme...
Article

Pseudoenhancement

Pseudoenhancement is an artifact encountered with contrast-enhanced CT, whereby the calculated density of a lesion is inaccurately increased. This phenomenon is most often problematic during evaluation of renal cysts by CT. On CT, it can be challenging to distinguish cystic versus solid renal l...
Article

Pulsatile portal venous flow

A pulsatile portal venous flow pattern can result from both physiological and pathological causes. In well subjects mild pulsatility, or in rare situations, even marked pulsatility has been described, particularly in thin subjects, with a venous pulsatility index of >0.5 with an inverse correla...
Article

Pulsatility index (ultrasound)

The pulsatility index (PI) (also known as the Gosling index) is a calculated flow parameter in ultrasound, derived from the maximum, minimum, and mean Doppler frequency shifts during a defined cardiac cycle. Along with the resistive index (RI), it is typically used to assess the resistance in a ...
Article

Pulse height analyzer

A pulse height analyzer is an instrument used to analyze the frequency distribution of the spectrum of photon energies that are captured by a Gamma camera.  Energy windows are selected to only allow certain photon energies that fall within a preset range to contribute to the output pulse.
Article

Pulse repetition frequency

Pulse repetition frequency (PRF) indicates the number of ultrasound pulses emitted by the transducer over a designated period of time. It is typically measured as cycles per second or hertz (Hz). In medical ultrasound the typically used range of PRF varies between 1 and 10 kHz 1. A number of ar...
Article

Quantitative computed tomography (bone)

Quantitative computed tomography (QCT) in bone imaging is a bone mineral density (BMD) measurement technique in which the CT scanner is calibrated using solid phantoms (made of calcium hydroxyapatite, representing various bone mineral densities) placed under the patient in a pad. With this calib...
Article

Quantitative computed tomography (thoracic imaging)

Quantitative computed tomography (QCT) in thoracic imaging has multiple potential applications although often not adopted in standard use in many centers at time of initial writing (2019). These include quantitating lung intensity / density and airway geometry in the normal adult human lung as...
Article

Quantum noise

Quantum noise, also called mottle is the main and the most significant source of noise in plain radiography. It is a random process due to fluctuations in the number of photons reaching the detector from point to point. This means that exposing the detector in the absence of an object would resu...
Article

Quenching

Quenching refers to rapid expulsion of the liquid cryogen used to maintain the MRI magnet in a superconducting state. Discussion Modern MRI scanners contain superconducting magnets which have very low energy consumption, made possible by maintaining internal subzero temperatures by way of a 'c...
Article

Rad (CGS unit)

The rad (symbol rad) is a legacy unit in the cgs system for the absorbed dose of ionizing radiation, although it remains in widespread use in the United States.  The rad is defined as the dose represented by 100 ergs of energy being absorbed by one gramme of matter. The erg is the unit of energ...
Article

Radiation damage (skin injury)

Radiation-induced skin injuries can occur in both radiotherapy and fluoroscopic procedures such as interventional radiology.  Acute radiation doses above 2 Gy are known to result in erythema, permanent epilation will occur at 7 Gy and delayed skin necrosis transpires above doses of 12 Gy.  The...
Article

Radiation dose considerations in CT fluoroscopy

Consideration needs to be made to the radiation dose to both the patient and radiologist in CT fluoroscopy, given the relatively high and continuous radiation exposure involved. Radiation exposure to the patient The patient surface dosage may range between 2 and 10 mGy/sec, with exposure times...
Article

Radiation effects on embryonic and fetal development

Radiation effects on embryonic and fetal development are generally considered low risk compared to the normal risks of pregnancy. Most diagnostic x-ray and nuclear medicine examinations are <50 mSv and have not been demonstrated to produce any significant impact on fetal growth and development. ...
Article

Radiation-induced carcinogenesis

Radiation-induced carcinogenesis is widely but not universally believed to occur at exposures from ionizing radiation used in medical imaging. It is thought to be a stochastic effect of ionizing radiation, with the linear no-threshold theory (LNT) proposing no "safe" level of radiation exposure,...
Article

Radiation-induced lung cancer

Radiation-induced lung cancers are a potential long-term complication of radiotherapy to the chest.  Besides lung cancer, sarcomas (osteosarcomas are the most common arising from the irradiated bones, and malignant fibrous histiocytomas the most frequently arising from the soft tissues), breast...
Article

Radiation protection

Radiation protection is based on the three fundamental principles of justification of exposure, keeping doses (of ionizing radiation) as low as reasonably achievable (optimization) and the application of dose limits. The International Commission on Radiological Protection (ICRP) is responsible f...
Article

Radiation risk factor

The radiation risk factor is the total lifetime risk of radiation-induced fatal cancer for the general population. The International Commission on Radiological Protection (ICRP) quantifies the radiation risk factor as 5% (5 in 100) per Sv, or 0.05% (1 in 20,000) per mSv. These figures are base...

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.