Which is the outcome when the tissue mass density is increased during differential absorption quizlet?

Contrast agents are used to image internal organs with x-rays, contrast agents have a higher mass density than tissue

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Covering x-ray production and interactions
What is differential absorption quizlet?
What is differential absorption?
In which of the following tissues does differential absorption Most depend on differences in mass density?
Which technical factor increases differential absorption quizlet?

Barium (56) & Iodine (53) Contrast are commonly used for their high atomic numbers and are positive contrast agents

Air, a negative contrast agent, can also be used, and is mainly used in the intestines along with barium (which is considered a double-contrast exam)

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Covering x-ray production and interactions

Question	Answer
Electrons emitted by the filament and directed to the target (traveling from the cathode to the anode)	projectile electrons
The strength of attachment of electrons to the nucleus	binding energy
X-rays produced by transitions of orbital electrons from outer to inner shells	characteristic x-rays
X-rays produced by interaction of a projectile electron with the nuclear force field of a target nucleus	bremsstrahlung x-rays
X-ray intensity, measured in milliroentgens (mR) or air KERMA (mGy)	x-ray quantity
Effective energy of the x-ray beam; penetrating ability	x-ray quality
The monoenergetic equivalent of an x-ray beam	effective energy
Section of metal added to the x-ray tube housing. Overall result is an increase in the effective energy of the x-ray beam (higher quality) and an accompanying reduction in x-ray quantity. Results in reduced patient radiation dose.	added filtration
The measure of x-ray energy of all x-rays, a graphical representation of the relative quantities of photons of each type of energy in the x-ray beam	emission spectrum
The x-ray tube target material principally used for mammography	molybdenum
calculate the energy of the characteristic x-ray produced when a K-shell electron is replaced by an M-shell electron in tungsten	66 keV
At what fraction of the velocity of light do 90 keV electrons travel?	60%
what does the discrete x-ray spectrum represent?	characteristic x-rays
When an x-ray imaging system is operated at 80 kVp, its emission spectrum represents an output intensity of 3.5 mR/mAs. What will be the output intensity if the voltage is increased to 90 kVp?	4.42 mR/mAs
How will the emission spectrum change is going from 80 kVp to 90 kVp?	higher amplitude and shift to right
What will happen to the x-ray emission spectrum if you change your imaging system from single phase to three phase?	higher amplitude and shift to right
How will the x-ray emission spectrum be changed if you add filtration to the x-ray tube?	lower amplitude and shift to right
How is the kinetic energy of the projectile electrons streaming across the x-ray tube increased?	increase kVp
Why is the x-ray tube considered an inefficient device?	only 1% of projectile electrons are converted into x-rays
What is the importance of K-characteristic x-rays in forming a diagnostic radiograph?	Significantly helpful when the kVp is above 70 kVp (the K shell binding energy for tungsten)
What is the range of energies of bremsstrahlung x-rays?	From near zero to an energy in keV equal to the kVp setting
Name the factors that affect the shape of the x-ray emission spectrum.	Voltage, rectification, filtration, tube current
What is the 15% rule?	A 15% increase in kVp is equivalent to doubling the mAs
What is the diagnostic range of x-rays?	20-150 kVp
The filtration provided by the window and oil bath of the x-ray tube	inherent filtration
The unit of x-ray quantity	Milliroentgen (mR) or milligray (mGy)
Addition of a filter shifts the x-ray emission spectrum to the high-energy side, resulting in an x-ray beam with higher effective energy, greater penetrability, and higher quality, but less intensity.	filtered x-ray spectrum
A kVp change equal to twice the mAs	15%
three filter materials used with diagnostic x-ray beams	Aluminum, molybdenum, rhodium
The thickness of filter or other absorbing material that will reduce intensity to half its original value	HVL
A compensating filter designed to shape the useful x-ray beam to the anatomic structure under examination so that the exposure of the image receptor will be more uniform	wedge filter
Identified numerically by half-value layer; also influenced by kVp and the added filtration in the useful beam	unit of x-ray quality
The approximate HVL of your x-ray imaging system	Usually totals 2 to 3 mm of aluminum equivalent
Another term for x-ray quantity, measured in mR or mGy	x-ray intensity
An abdominal radiograph taken at 84 kVp, 150 mAs results in patient radiation exposure of 650 mR. The image is too light and is repeated at 84 kVp, 250 mAs. What is the exposure?	1083 mR
An image of the lateral skull taken at 68 kVp, 20 mAs has sufficient optical density but too much contrast. If the kVp is increased to 78 kVp, what should be the new mAs?	10 mAs
A chest radiograph taken at 180 cm SID results in an expsoure of 12 mR. What would the exposure be if the same radiographic factors were used at 100 cm SID?	38.9 mR
Old technique: 60 kVp, 10 mAs = 28 mR New technique: 55 kVp, 10 mAs = what new intensity?	23.5 mR
The kVp is reduced from 78 to 68 kVp. What should be done to the mAs to maintain the same exposure of the image receptor?	double the mAs
what is the relationship between x-ray quantity and mAs?	directly proportional
List two ways x-ray beam can be shifted to a higher average energy?	Increase kVp or added filtration.
Why is aluminium used for x-ray beam filtration?	Because it is efficient at removing low-energy x-rays, and because it is readily available, inexpensive, and easily shaped into filters
Describe the use of a wedge filter during a foot x-ray	The thicker part of the wedge should be positioned toward the toes in order to equalize optical density.
Does adding filtration to the x-ray beam affect the quantity of x-rays reaching the image receptor?	Yes
Effect of increasing mAs on x-ray quality	none
Effect of increasing mAs on x-ray quantity	increase
effect of increasing kVp on x-ray quality	increase
effect of increasing kVp on x-ray quantity	increase
effect of increasing distance on x-ray quality	none
effect of increasing distance on x-ray quantity	decrease
effect of increasing filtration on x-ray quality	increase
effect of increasing filtration on x-ray quantity	decrease
The relationship among transmitted x-rays, photoelectrically absorbed x-rays, and Compton scattered x-rays resulting in the x-ray image	differential absorption
Scattering of very-low-energy x-rays with no loss of energy; also called coherent or Thompson scattering	classical scattering
The quantity of matter per unit volume, usually specified in kilograms per cubic meter (kg/m3). Sometimes reported in grams per cubic centimeter (gm/cm3).	mass density
The threshold energy required by a photon to undergo pair production	1.02 MeV
A high-atomic number material (for example, iodine and barium), or a low density, low-atomic number material (air) administered in liquid or gas form to improve the contrast resolution of an x-ray examination	contrast agent
X-ray ionization resulting in x-ray scattering	Compton effect
The reduction in x-ray beam intensity as a result of photoelectric absorption and Compton scattering	attenuation
Having a single energy. Characteristic x-rays are monoenergetic, and the effective x-ray energy of an x-ray beam is the monoenergetic equivalent of the actual beam.	monoenergetic
Electrons released in ionization as the result of photoelectric interaction and Compton scattering	secondary electron
An x-ray absorption interaction in which the x-ray is not scattered but totally absorbed. A photoelectron is then released from the atom.	photoelectric effect
what are the two factors of importance to differential absorption?	keV and atomic number of absorber
1000 x-rays with energy of 140 keV are incident on bone and soft tissue of equal thickness. If 87 are scattered in soft tissue, approximately how many are scattered in bone?	87
Why are iodinated compounds such excellent agents for vascular contrast examinations?	high atomic number and high mass density
Compton-scattered x-rays leave the scattering object in the approximate direction of the incident x-ray beam.	backscatter radiation
Which 3 of the 5 basic mechanisms of x-ray interaction with matter are not important in diagnostic radiology?	Classical, photodisintegration, pair production
Why are there 3 mechanisms of x-ray interaction with matter that are not important in diagnostic radiology?	The x-ray energies involved are outside of the diagnostic energy range
Does the probability of the Compton effect depend on the atomic number of the target atom?	No
when kVp is increased, is Compton scattering increased or reduced?	decreased
how much more likely is it that an x-ray will interact with bone than with muscle?	(13.8/7.4)3 = 6.5
What is the relationship between atomic number and differential absorption?	Differential absorption resulting from photoelectric effect is proportional to the third power of the atomic number. Compton effect is unrelated to atomic number.
What is the relationship between mass density and differential absorption?	The probability of interaction is proportional to mass density, and therefore, so is differential absorption.
What kVp is used to penetrate barium in a contrast examination?	90 kVp

What is differential absorption quizlet?

What is differential absorption? The difference in x-ray interactions with matter (what is absorbed and what is transmitted)

What is differential absorption?

Basically, an x-ray image results from the difference between those x-rays absorbed photoelectrically in the patient and those transmitted to the image receptor. This difference in x-ray interaction is called differential absorption.

In which of the following tissues does differential absorption Most depend on differences in mass density?

Physics U6 &HW.

Which technical factor increases differential absorption quizlet?

What technical factor directly controls differential absorption? Rationale: Because it controls the penetrating ability of the beam, kVp directly controls differential absorption.

Which is the outcome when the tissue mass density is increased during differential absorption quizlet?

Covering x-ray production and interactions

What is differential absorption quizlet?

What is differential absorption?

In which of the following tissues does differential absorption Most depend on differences in mass density?

Which technical factor increases differential absorption quizlet?

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