Ch. 5 HA Understanding other imaging modalities Flashcards
The feature of a radiographic image that affects the clinician’s ability to see details and detect lesions
Contrast
Quality inherent in the film type and the processing techniques that is not changeable by the operator
Film/ detector contrast
Physically similar to x-rays, but they are generated spontaneously from the decay of radioactive isotopes
Gamma rays
The “hole” in the center of the CT scanner
Gantry
Numeric scale for representing different tissue characteristics by their x-ray density (or “electron density”)
Hounsfield Unit
Radiopaque medium used in imaging: iodine and barium are examples
Positive contrast agent
Affected by the absorption characteristics of the tissue being imaged and the imaging parameters
Subject contrast
Tube that is placed by a neurosurgeon to relieve intracranial pressure due to increased cerebrospinal fluid (hydrocephalus)
Ventriculoperitoneal shunt
4 important characteristics of x-ray
- X-rays have no mass
- Travel at the speed of light
- Can penetrate matter
- Are invisible to the human eye and are electrically neutral
Tissues that absorb a greater quality of the x-rays appear ________ on the x-ray image
White
The ________ areas on an x-ray image indicate areas of lower density.
Black
In a normal x-ray, bones absorb the beam _______ and are displayed as white
Most
Air absorbs the beam ________ and is displayed as black
Least
The difference between adjacent densities or structures is called ____________
Contrast
Which radiograph is a good example of high contrast?
Chest x-ray
Nuclear medicine differs from conventional radiography in that it uses________ rays, which are physically similar to x-rays but are generated spontaneously from the decay of radioactive isotopes
Gamma
When radionuclide substances are administered, they are distriduted according to the patient’s physiology to certain tissues or sites called _________ via the pharmaceutical, while some is distributed diffusely to all tissues
Targets
How does nuclear medicine determine the cause of clinical problem(s) differently from other imaging modalities?
Nuclear medicine determines the cause of clinical procedures due to physiologic malfunctions of a bone, organ and tissue. Other modalities detect pathology based on the structual appearance. Nuclear medicine evaluates tissue at the cellular level, images appear as hot or cold spots rather than anatomical
A _______ spot has reduced uptake of radionuclide, whereas a __________spot demonstrates increased uptake or hyperfunctioning tissue.
Cold, Hot
CT imaging is based on ________ imaging
X-ray and radiographic
