Research Profile - Medical Imaging Glossary

Biomarker: A biomarker is simply a sign of the presence or progress of a disease or condition, such as a raised temperature signalling a fever. It can also be a substance introduced into an organ to see how it functions – for example, using rubidium chloride as an isotope to assess blood flow to the heart (myocardial perfusion). In health research, biomarkers are specific biochemicals used to measure the status of a disease or the effects of a treatment.

CT Scan: CT stands for computed tomography.  A CT Scan commonly refers to an x-ray procedure that uses a computer to produce a detailed image (a tomogram) of a slice or a section of the body. Sometimes called a CAT Scan – for computed axial tomography.

Cyclotron: A cyclotron is a type of particle accelerator that increases the speed of protons as they follow a spiral path through it. Canada has several cyclotrons and the one at TRIUMF at the University of British Columbia is the world's largest. Cyclotrons could be used to provide an alternative source of isotopes such as Technetium for medical imaging.

Isotope: A medical isotope is a small amount of a radioactive substance that is taken orally or intravenously to capture images of the body or treat disease.

MRI: Stands for magnetic resonance imaging. It involves using a powerful magnetic field, radio frequency pulses and a computer to produce three dimensional pictures of parts of the body to assess their condition or spot diseases. MRIs provide better contrast than CT Scans and are especially useful for images of the brain, the musculoskeletal and cardiovascular systems, and for detecting cancer.

PET Scan: Stands for positron emission tomography. This is a procedure in which a patient is given a radiopharmaceutical that travels to the desired site where it gives off gamma rays to create a picture of how the organ or tissue is functioning. This metabolic information is often coupled with the structural image provided by a CT Scan.

Technetium: Technetium-99m or 99mTc is an isotope widely used in radiopharmaceuticals because it emits easily detectable gamma rays and has a half-life of only a few hours. The Chalk River reactor produces much of the world's supply of molybdenum-99, the precursor to Technetium-99m.

Ultrasound: In ultrasonic imagingsound waves travel through tissues and organs and are reflected back according to density. An electronic apparatus receives these echoes and measures their intensity and their positions to create an image.

X-ray: The oldest form of medical imaging – discovered at the end of the 19th century – it involve using electromagnetic radiation to penetrate the body to create images of bones and organs.