A very important principle in radiation protection. It is designed to use the minimum amount of radiation to produce an adequate test. Very commendable efforts have been made in recent years in Quebec to follow this principle as closely as possible, particularly concerning the doses used during CT examinations. Note that the evaluation of the relevance of a radiological examination, and its replacement by a method that does not use X-rays are an integral part of this system (e.g. abdominal ultrasound or magnetic resonance imaging used instead of a CT scan.)
Chemical substance having the property of blocking blood coagulation. This medication comes in many forms:
- Oral: Coumadin, Eliquis, Xarelto
- Intravenous: Heparin
- Subcutaneous: low molecular weight Heparin, of which Innohep is the best known.
Substance having the property of blocking the spasms of the smooth muscles of the intestine or urinary tract. We use these medications in barium enemas and virtual colonoscopies. Some contra-indications exist; they will be checked in advance, of course.
Synonym of proton. This is the positive elementary charge of the nucleus. Hydrogen is its most common representative. This molecule, being the basis of the composition of water (H²O), and the body being composed of 98% water, is the most represented in the human body.
It is also one used in magnetic resonance imaging to create high-contrast images of difficult areas analysed by other imaging techniques.
Artificial modification of the radiological image by hyperdense material (jewelry or metal prostheses which hinder the quality of the film obtained). Several other types of artifacts can be found on an x-ray film. One of the most common is the respiratory artifact which is accompanied by a kinetic blur on the radiological image, similar to that of a subject who would have moved during a standard photographic image.
This is the articulation between the ascending branch of the mandible and the temporal bone to which it is attached.
Barium is a white, chalky liquid that covers the inside of organs, and clearly indicates their outline on the radiological image. A special x-ray (radioscopy) forms a moving image of barium, which circulates in the gastrointestinal (GI) tract.
Technique that aims to deposit a cortisone substance at the level of the emergence of a nerve root outside the spinal canal. Although the technique is similar to the faceted block, it is more complex and requires more specialized equipment to do this. This technique is not performed here, but we refer patients in hospitals to do so.
Material that is inserted between the teeth during some special sequences in dental radiology to evaluate the contact between them (dental occlusion). These specific sequences are performed as required, based on information provided by your referring physician or dentist..
A technique which seeks to deposit a cortisone substance in the emergence of a nerve root outside the spinal canal (nerve roots emerge at the conjugate foramen). Although the technique is similar to a facet block, it is more complex and requires more specialised equipment. This technique is not performed here, but we refer patients to a hospital to have it done.
This is the final stage of coronary artery disease or atherosclerosis. The detection and quantification of their extent is done by examining the “calcium score”. The latter is an indicator of the severity of coronary artery disease and allows us to stratify the risk of a major event in order to plan a possible treatment.
Normally, calcium in the human body is located in bones and teeth. The presence of calcium outside these structures is called lime deposit. These pathologies are particularly common in the musculoskeletal system, either around the joints (tendinitis or calcific bursitis of the shoulder) or in the muscles (myositis ossificans).
Doppler is a special ultrasound technology, which uses the properties of the circulating liquids (the blood), and the wavelength variation associated with these movements, to determine their speed and direction. These techniques are particularly useful on the heart and blood vessels, to allow the detection of obstructive or occlusive phenomena, or even of possible leaks (pseudo-aneurysm, valvular insufficiency, etc.).
This is the ultrasound beam emitted by the probe placed on the skin, which is oriented towards an organ and reflected by the latter, and recaptured by the same probe, which produces an image of the structure thus investigated. The ultrasound beam only circulates well in water (and bounces in the air) and this is why a gel must be applied between the probe and the skin, to prevent artifacts and allow a better quality image. .
Similarly to barium, gadolinium is a rare earth metal. Its ferromagnetic properties make it the dye of choice in the investigation of certain pathologies in magnetic resonance imaging. Side effects are rare (much more than those with iodine) and tolerance is usually not a problem. Allergic reactions are very rare, but not impossible. This will always be checked prior to any injection.
A synovial sheath is a structure similar to a pulley which partially envelops the tendon and which secretes a liquid to prevent friction and guide the tendon in its flexion or extension action. Certain pathologies (Dupuytren's disease) thicken the tendons or sheaths and on occasion, these must be cut to free the tendon and allow it to carry out its normal movement (example; trigger finger pathology).
Iodine is a basic atomic element bearing No. 53 in the Periodic Table of Elements. Its high atomic density makes it an excellent product to absorb x-rays and also allows better visualisation of organs that one wishes to investigate.
Allergy problems with iodine are relatively frequent and of varying intensity. This point will always be checked prior to any possible injection. Note that in many situations, it is possible not to use such an injection or to use other methods of testing that do not require the same product.
The other potential problem is that of kidney function that can affect some patients, especially diabetics. It is thus sometimes necessary to check kidney function before (and sometimes after) an iodine injection. The dosage of blood creatinine is the test of choice to make.
Generally, the injection of iodine will be used in the investigation of tumour or inflammatory lesions because the breakage of the vascular barrier resulting from these pathologies causes a release of the product in the soft tissues which border it, thus allowing its detection.
The vascular regions or barriers that are broken appear denser than those which are integrated and in which the dye remains in the vessels instead of breaking into the soft tissue of the surrounding areas.
A cyst is a closed sac, which has its own epithelial membrane, and which is enclosed within an organ. In the vast majority of cases, these cysts contain a liquid secreted by the epithelium and may become symptomatic depending on the size and tension created by the content in the organ in question (the classic example being that of a mammary cyst).
All organs of the body may contain cysts. In some cases, the content may be gaseous rather than fluid. Some cysts can become infected spontaneously or as a result of manipulation.
The Pseudo Cyst differs from the cyst in that no epithelium surrounds the liquid. Rather, the surrounding soft tissues hold the liquid in place (the classic example being that of the pseudo pancreatic cyst).
Refers to any substance having the property of absorbing X-rays and of thus influencing the radiological image obtained. Barium and Iodine are the two main radiopaque substances used in radiology.
Synonymous with cancer, the term neoplasm expresses the abnormal proliferation of cells in an organ which interferes with normal operation.
Disease of bone demineralisation (loss of calcium and phosphorus) resulting in increased bone fragility and having an increased risk of fracture.
The term PACS is an acronym for Picture Archiving and Communication System. This is a system allowing the archiving and exchange of radiological examinations. The latter was developed at the time of transition from the old model of radiology (analog), to the technology used now (digital). The advantages of this system are numerous, both in terms of efficiency and in ease of exchange among the various parties involved.
A polyp is a tissue outgrowth developing from mucosal tissue which, in most cases, is benign.
Occasionally, especially in the colon, when they reach a certain size, these polyps become a risk of carcinogenesis. Colon cancer usually develops on polyps larger than 1cm. All the efforts of early detection of the disease aim to detect these polyps before they become cancerous.
Synonym for spine. It is the stack of vertebrae articulated together and each spaced apart by an intervertebral disc. Its primary function is the protection of the spinal cord, the main nerve bundle, providing motor skills and sensitivity to the various structures of the human body.
Process of emission of transmission of energy involving a particle.
In medical imaging, two main classes of radiation are used.
The first is the electromagnetic radiation of x-rays. In this case, an electric current applied to an anode allows the release of the rays, which are directed toward the area of the subject to be studied. This radiation is controlled at the source.
In contrast, the radiation used in nuclear medicine is continuously emitted by a radioactive source, which will be used to image the various structures to be investigated.
These two types of radiation involve a range of protective measures to limit their impact on the structures to be studied. These range from the evaluation of the relevance of the study to the limitation of the exposed areas, to the protection of the surrounding areas at the time of design of examination rooms (see radiation protection).
The principle of ALARA is very important in radiation protection.
Ionizing radiation emitted following the application of an electric charge to an anode (see the term radiation above).
The risk of a fracture occurring is a function of the density of the calcium present in the bone evaluated. Bone densitometry seeks to evaluate the calcium density in the bones and to determine the risk that a fracture may occur in the short or the long term. This will help to plan possible preventive treatments.
These are all techniques and modalities for remote consultation of examinations at one site. It proves to be particularly relevant in the growing radiological complexity and the need to consult on occasion, specialists at the time of specific exams.
Teleradiology, as part of the PACS system also allows the exchange of information with the various partners involved (your referring physician or the specialist you may eventually consult.
In medical imaging, this term refers to the specially trained personnel that carry out various radiological examinations. They are responsible for all stages, from gathering information, to the completion of the test as such. Their involvement is particularly important in the field of radiation protection.
All technologists are able to perform basic radiological tests (general radiology). Additional training is required to handle a variety of specialised equipment, whether it is ultrasound, computed tomography, mammography or magnetic resonance imaging.
They are subject to the controls of a professional organisation (OTIMRO), which ensures the obtaining and maintaining of skills, as well as the protection of the public.
A group of pathologies characterised by the deposit of calcium hydroxyapatite in the tendons around the joints or articulations. The most common is undoubtedly the calcific tendinitis of the supraspinatus, at the level of the shoulder.
Structure of connective tissue allowing the insertion of a muscle into the bone, in addition to the transmission of mechanical energy from the muscle to the structure to which it is attached.
The mammary gland is composed of a combination of three different types of tissue: glandular tissue (which secretes human milk), connective or fibrous tissue, as well as adipose tissue. The relative proportion of each of these tissues varies greatly for the same person, according to the time of life, but also from one person to another.
The predominance of adipose tissue, which changes with age, favours the interpretation of images created after a mammogram, because the fat is not very dense and results in a black image. Therefore, tumour lesions (spots, artifacts or whitish calcifications) that one attempts to detect by this examination will be much more visible on a black greasy background, than on a white background of glandular or fibrous tissue.
Hormone therapy generally stimulates tissue density.
The dominant composition of breast tissue often determines the clinical appearance of the breast. Thus, a fatty breast will be much more flexible and carry fewer nodules than a glandular breast, which will be firmer and often more painful, especially before menstruation.
The term tumour refers to the abnormal proliferation of healthy tissue (benign tumour) or neoplastic tissue (malignant tumour).
Various radiological investigations are often aimed at the detection or monitoring of such pathologie.
