Glossary
Contrast
Contrast is a medicine that is used during certain imaging tests that help the doctor see specific parts of the body. There are a few different types, and in some cases patients need more than one type for a single scan. You may receive contrast through an IV before or during the scan. Getting contrast doesn't hurt, but it does feel cool going into the arm. Some patients report a metallic taste when receiving contrast, but lasts only a few minutes.
CT Scan
A CT (Computed Tomography) scan is a medical procedure that involves moving a patient through a cylindrical machine that takes a series of X-rays which allows your doctor to see inside the body. The scanner rotates to take specialized X-rays called “slices” of the patient’s body that provide clear images of their internal anatomy. CT scans are used for a variety of different reasons, such as diagnosing injury and disease, planning future medical procedures, or monitoring preexisting treatments and illnesses. CT scans often focus on a certain region of the body; usually the head, chest, or abdomen and pelvis regions due to the number of vital organs located in those areas, but patients can receive scans on any part of their body. Scans can also combine different areas or scan the patient’s entire body depending on the location of the sickness or injury. CT scans are performed with or without contrast, which is a liquid used to improve the clarity of X-rays produced by CT scans. Contrast can be administered through an IV or orally that shows up on the scanner and outlines tissues and organs more clearly on the X-ray image.
Electromagnetic Radiation
Form of energy exhibiting wave-like behavior as it travels through space and has both electric and magnetic field components.
Ionizing Radiation
Ionizing radiation is radiation with enough energy to produce ions in the medium through which it passes. Ions are atoms or molecules that have gained or loss electrons to change their charge. Since electrons determine chemical behavior, the production of ions can kill cells. If these ions break molecular bonds, they can damage DNA and cause cancer.
Mammogram
A mammogram is an examination of the female breast using X-rays that helps find growths that are too small to feel during a breast exam. It is one way to screen for breast cancer.
Mean
The mean is the average of a set of numbers. To calculate mean, add up all the numbers, then divide by the number of numbers in the group.
Median
To find the median number in a group, all the numbers are arranged in value order. Then, find the middle number. If there are two middle numbers, then those numbers are averaged together.
mSv
milliSievert; equivalent dose of ionizing radiation.
Multiple Phase
This term identifies types of exams where imaging is repeated more than once on the area. The images are then compared to identify changes.
Natural Background Radiation
This includes cosmic radiation (from our sun and other stars), terrestrial radiation (from the Earth), and internal radiation that comes from our own bodies.
Non-Ionizing Radiation
Energy waves (radiation) that do not have enough energy to break molecular bonds. Types include visible light, infrared , microwave, and radio waves. This type of radiation does not damage DNA or cause cancer.
PET
A device that produces cross-sectional x-rays of metabolic processes by means of positron emission tomography.
Radiation
Radiation is essentially energy that can originate from many different sources. We are exposed to radiation constantly from our water, soil, air, and other natural, everyday sources. This natural radiation is unavoidable and low enough in intensity to not pose any serious danger to people over time. In addition to natural exposure, people can also be deliberately exposed to controlled levels of radiation for medical purposes in the form of computed tomography (CT) scans. These scans emit radiation in the form of X-rays, which is a form of ionizing radiation. Ionizing radiation is a type of radiation has enough energy to knock electrons off of atoms, causing them to become charged. The ionization of atoms in a patient’s tissue damages their DNA molecules, and this damage can sometimes lead to the development of cancer. However, since these ionizing X-rays can pass through the body, radiologists can use them to produce useful images of a patient’s internal anatomy, which usually outweighs the low risk of cancer.
Ultrasound
Also called Sonography, this is a safe, painless exam that uses sound waves to create images inside the body.
X-ray
Relatively high-energy photons, used for their penetrating power in radiography, radiology, radiotherapy, and scientific research.