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CHAPTER 7-CAllegood

SWGTC EXPOSURE CH 7 Wallace-RADIOGRAPHIC CONTRAST

QuestionAnswer
The amount of radiographic contrast is judged by the number of _________ present on the radiograph? grey tones
There can be too little contrast when the radiograph appears? very gray
There can be too much contrast when the radiograph appears? mostly black and white
The radiographic contrast caused by the differences in the composition of the patient's body tissues? subject contrast
The degree of difference between adjacent densities on a radiograph? radiographic contrast
If the colors of black and white are adjacent to each other, they display a _____amount of contrast? high
If two similar shades of gray are next to each other they display a _____ amount of contrast? low
The image on a radiograph containing the various shades of gray is ? gray scale image
Short scale contrast = high contrast
long scale contrast= low contrast
Subject contrast is caused by? the tissue density differences, atomic number differences, and thickness differences of the patient's body parts
The atoms in ____ are very compact. bone
In a stable atom the number of electrons equals the number of ________? protons
List the body parts in order from less absorbing power to more absorbing power. Air, Fat, Water, Muscle, and Bone
List the body parts from more radiographic density to less radiographic density. Air, Fat, Water, Muscle, and Bone
Patients who are in good physical shape usually display the _______ subject contrast. highest
Bones that have lost minerals because of disease become ____ dense and x-ray photons pass through them more ______. less; easily
Patients who have retained water in their bodies will display a _____ is subject contrast. decrease
Water causes an _______ in the amount of scattered radiation produced in the patient's body. increase
Adding ____ _____ to a body part changes its tissue density. contrast media
The most common type of contrast media are? air, iodine, and barium
Adding air to a body part ______ its tissue density compared to the structures around it. decreases
Adding iodine or barium to a body part ______ its tissue density compared to the structures around it. increases
________ and _____ are used in the gastrointestinal tract. Barium and air
Used in the kidneys and gall bladder Iodine
What is the main controlling factor for radiographic contrast? KVP
High KVP= high photon energy
Low KVP= low photon energy
Hgih KVP= high photon energy= low contrast=long scale
Low KVP= low photon energy= high contrast=short scale
The major KVP control changes the KVP by a unit of ? 10
The minor KVP control changes the KVP by a unit of? 1 or 2
KVP settings usually range from ______ to _____. 40; 120
The radiation that gets through the patient's body is called? exit radiation or remnant radiation
Scattered radiation ________ radiographic contrast. lowers
High kvp= more scattered radiation= low contrast image
Low kvp= less scattered radiation= high contrast image
Three things that can happen to the primary x-ray photon as they enter the patient's body are? They can be absorbed, they can be scattered, and they can pass through and hit the film.
As the x-ray photons are absorbed or scattered, the radiation intensity of the original beam is ________. reduced
The reduction of radiation intensity by absorption or scattering as the beam passes through matter is called? attenuation
Created by: radtech