Chapter 5 Understanding other imaging Modalities H&A Flashcards
The “hole” in the center of the CT scanner?
Gantry
Tube that is placed by a neurosurgeon to relieve intracranial pressure due to increased cerebrospinal fluid (hydrocephalus)
Ventriculoperitoneal shunt
Radiopaque medium used in imaging; iodine and barium are examples
Positive contrast agent
Quality inherent in the film type and the processing techniques that is not changeable by the operator
Film/detector contrast
Affected by the absorption characteristics of the tissue being imaged and the imaging parameters
Subject contrast
The feature of a radiographic image that affects the clinician’s ability to see details and detect lesions
Contrast
Physically similar to x-rays, but they are generated spontaneously from the decay of radioactive isotopes
Gamma Rays
Numeric scale for representing different tissue characteristics by thir x-ray density (or”electron density”)
Hounsfield unit
List 4 important characteristics of x-rays
They have no mass, travel at the speed of light, can penetrate matter, and are invisible to the human eye and are electronically neutral
Tissues that absorb a greater quanity of the x-rays appear “ how” on x-ray
White
“Blank” Areas on an x-ray image indicate areas of lower density
Black
In a normal x-ray, bones, absorb the beam “blank” and are displayed as white.
most
Air absorbs the beam “blank” 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
Name two contrast media that are used in radiography
Barium and Iodine
Ct imaging is based on “what”
x-ray or radiographic
The method of CT scanning that can aquire the entire torso in one breath-hold is called?
spiral or helical,CT
What do the “White” areas on a CT tell about an image
Contrast has been given
Nuclear medicine differs from conventional radiography in that it uses”what” rays, which are physically similar to x-rays but are generated spontaneously from the dacay of radioactive isotopes
Gamma
When radionuclide substances are administered, thay are distributed according to the patient’s physiology to certain tissues or sites called”what” via the pharmaceutical, while some is distributed diffusely to all tissues.
targets
A “?” spot has reduced uptake of radionuclide, whereas a “?” spot demonstrates increased uptake or hyperfunctioning tissue.
cold, hot
VCUG (placing a cath into the bladder) is used to determine?
Refux (when urine refuxes back up the ureter into kidney)
VP shunt connects the ventricles of the brain to the ?
Abdominal cavitiy
Does CT have the same range of grays, blacks, and whites as ultrasound?
Yes; true
Does CT have the same density configuration as x-ray?
Yes; true
Hot spots in nuclear medicine demonstrate decreased or increased cellular function or tracer accumulation than the surrounding tissue
More; increased
Cold spots in Nuclear medicine indicate decreased or increased cellular function or tracer accumulation
Less; decreased
Hot spots indicate increased or decreased uptake of the radionuclide?
Increased
Pairs CT and nuclear medicine is a hybrid image
PET
