RADR 1213 Final all Unit Exams

Filtration is the process of eliminating undesirable ____ by the insertion of absorbing materials into the primary beam

low-energy x-ray photons

Filtration permits the radiographer to ____ the photon emission spectrum into a more useful beam

narrow

Beam filtration does what to patient dose?

it decreases patient dose

Beam filtration affects patient dose by

removing low energy photons

In general, low-energy x-ray photons

are absorbed by the patient

What are considered filter media as the beam traverses toward the patient?

Glass, dielectric oil, and aluminum

The most common diagnostic x-ray beam filter material is

Aluminum

All filtration can be expressed in terms of the thickness of _________ equivalency.

Aluminum

The amount of material that will reduce the intensity of the primary beam to one-half its original value is termed the

Halve-value layer

The half-value layer is typically expressed in

Al/Eq

If the half-value layer of diagnostic radiographic equipment is too low, it may be corrected by

increasing the primary beam filtration

What is affected by half-layer value?

Patient skin exposure

What term describes filtration that is part of the x-ray tube, the tube housing, and the collimation device?

inherent

What filtrations would result in the lowest entrance skin exposure to the patient?

1.0 Al Eq

In mammography tubes, the glass window of the tube is replaced with __________ to reduce patient skin exposure.

Beryllium

Most of the inherent filtration of a typical x-ray equipment comes from the

window of the glass envelope

The collimator device is considered part of the ____ filtration.

added

A Thoraeus filter combines all of the following materials

Copper, tin, and aluminum

The problem of uneven image receptor exposure due the heel effect is solved by a

Compensation filter

What compensating filters is used most commonly in the radiography of femur?

Wedge

The _____________ portion of the wedge filter is placed over the less dense part of the patient.

Thickest

Total beam filtration is equal to the sum of ____ filtration.

inherent and added

When filtration is ____, technical factors must be ____ to maintain the same density.

increased; increased

For an x-ray beam operated at 90 kVp, the required minimum filtration must be

1.0 mm Al Eq inherent plus 1.5 mm Al Eq added

A compensating wedge filter would be appropriate for

AP foot radiography

The build-up of tungsten deposits on the inside of an aged x-ray tube adds to the

Inherent filtration

The factors that affect x-ray emission under the direct control of the radiographer are called the ____ factors.

prime

The prime factors include

kVp, mAs, distance

Milliamperage-second (mAs) directly affects

Beam quality

The factors that directly affect x-ray quantity are

mA and time (S)

Total x-ray beam quality is numerically represented by the

HVL

The factors that directly affect x-ray quality are

kVp and beam filtration

Using digital detector technology, the term used to express exposure to the detector is

Exposure index (EI)

What is true regarding digital imaging, from the choices below.

The brightness on a review monitor is not related to x-ray exposure

As the mA doubles, the number of electrons flowing from cathode to anode

increases twofold

The product of tube current and exposure time is equal to

x-ray beam quantity

The primary factor controlling x-ray beam quantity is determined by

mas

In order to increase image receptor (IR) exposure by 40 percent, the radiographer would

Change the mAs from 15 to 21 mAs

If the mAs of a radiograph is increased from 10 to 20, the result will be

an increase in the EI number from 125 to 250.

The relationship between mAs and exposure is

directly proportional

Exposure indicators used in digital imaging have a direct or indirect relationship with exposure, depending upon the manufacturer. If the digital system you are using has an indirect relationship with exposure, your exposure reference value (S#) will

decrease with increased exposure

Increasing the kVp for an exposure will

cause the electrons to travel faster from cathode to anode

Increasing the energy of an incident electron will result in the production of an x-ray photon with

greater energy

If kVp is doubled, the amount of x-ray photons created approximately increases

fourfold

Kilovoltage is the primary controlling factor of

x-ray beam quality

An increase in kVp by 15 percent will cause an approximate ____ in the exposure to the receptor.

Doubling

Adjustments in mAs should be used to control IR

Exposure

X-ray beam penetrability is primarily controlled by

kVp

The relationship between the intensity of radiation and distance is the

inverse square law

When using a digital image receptor (IR)

control IR exposure with predictable changes in mAs

All factors remaining constant, what set of exposure conditions would yield an image with the HIGHEST image receptor (IR) exposure?

400 mA, 187 ms, 56"SID, 88 kVp

After completing an upright abdomen radiograph using A.E.C., you notice some degree of motion artifact on the final image. To improve the repeat image results, your best option would be to

increase kVp by 15% with mAs compensation

The length of the exposure time (S) for a radiograph, is used to primarily control

motion distortion

Given 40 mA and an exposure time of 0.20 second, calculate the mAs.

8 mAs

Given 50 mA and an exposure time of 0.50 second, calculate the mAs

25 mAs

Given 25 mAs and a milliamperage of 100, calculate the exposure time.

0.25 sec

Given 5 mAs and a milliamperage of 200, calculate the exposure time.

0.025 sec

Given an exposure time of 0.15 second and a milliamperage of 100, calculate the mAs

15 mAs

Given an exposure time of 0.06 second and a milliamperage of 400, calculate the mAs.

24 mAs

A radiographer takes an initial radiograph using the technical factors of 50 mA at 0.46 sec. There is involuntary motion on the radiograph, but the radiographer wants to maintain IR exposure. If the exposure time is reduced to 0.115 sec, what is the new mA?

200 mA

A radiograph is produced using 20 mAs at 65 kVp. To double the exposure, what kVp should be used?

75 kVp

An x-ray exposure of 200 mR is recorded at a distance of 40 inches. If the same technical factors are used, what will the exposure be if the distance is increased to 72 inches?

61.7 mR

An x-ray exposure of 100 mR is recorded at a distance of 40 inches. To reduce the exposure to 25 mR, to what will the distance need to be changed?

80 inches

An acceptable radiograph was taken using 40 mAs at 80 kVp at a distance of 60 inches. A second radiograph is requested at 40 inches. What mAs should be used to produce this radiograph with a 40-inch distance?

17.8 mAs

An acceptable radiograph was taken using 20 mAs at 70 kVp at a distance of 40 inches. A second radiograph is requested at 72 inches. What mAs should be used to produce this radiograph with a 72-inch distance?

65 mAs

When an x-ray photon passes through matter, it undergoes a process called

attenuation

During the process of attenuation, x-ray photons in the beam

reduce in number, lose energy, and produce ionizations

Which atomic shell possesses the highest binding energy?

K shell

In which element are the inner-shell electrons more tightly bound to the nucleus?

lead (Z = 82)

Which energy-level electrons possess the highest total energy?

N shell

As the electron shells move farther from the nucleus, total electron energies ____ and binding energies ____.

increase, decrease

When x-ray photons interact with matter and change direction, the process is called

to scatter

If a photon interacts with matter and scatters, the photon

exists with less energy

When an x-ray photon with a slightly greater energy than the binding energy of the inner-shell electron interacts with that inner-shell electron, the following interaction results:

photoelectric absorption

During photoelectric absorption, a/an ____ shell electron is ejected

inner shell

During photoelectric absorption, the ejected electron is called a/an

photoelectron

A photoelectron

is matter and possesses energy, is capable of creating biological changes, and typically travels 1-2 mm in soft tissue

When an electron from an outer shell fills a vacancy in an inner shell,

a photon is released

During the photoelectric interaction, as an electron transfers from an outer shell to a vacant inner shell, energy is released in the form of

characteristic photon

Secondary radiation energies are highest for which element?

Barium

An interaction that occurs between very low energy x-ray photons and matter is called ____ scatter.

Coherent, classical, or Thompson

During coherent scattering, the scattered photon possesses ____ as the incident photon.

the same energy, frequency, and wavelength

Compton scattering occurs when an incident x-ray photon interacts with an ____ electron.

outer shell electron with low binding energy and high kinetic energy

The photon that exits the atom after a Compton scattering interaction is called the Compton

scattered photon

During Compton scattering, the incident photon energy is divided between the

Recoil electron and the scattered photon

As the angle of deflection is increased from 0° to 180°,

greater energy is imparted to the recoil electron

During fluoroscopic studies, the primary source of exposure to the radiographer is due to

Compton scattering

During which interaction with matter is the x-ray photon converted to matter in the form of two electrons?

pair production

In which process is matter converted back to energy?

Annihilation reaction

What interactions has a significant impact on the x-ray image?

Photoelectric absorption

In the human body, ____ is the predominant interaction through most of the diagnostic x-ray range.

Compton scattering

What interactions is responsible for the contrast in UGI studies?

Photoelectric interactions

In an effort to decrease the mAs of an exposure, the 15% rule of kVp change may be considered. Changing the original kVp of 84 using the 15% rule will have what impact?

Greater compton scatter interactions

The incidence of the photoelectric effect increases with

increasing atomic number of the absorber

In diagnostic radiology, radiographic image contrast is principally due to the predominance of

photoelectric interactions

A radiographer can best minimize the amount of scatter radiation reaching the image receptor by restricting the beam.

True

When kilovoltage is increased with no other changes in technical factors, fewer scattered photons will result.

False

Image quality is improved when scatter reaching the image receptor is reduced.

True

Soft tissue absorbs more radiation and produces more scatter than bone.

False

Penumbra is a geometric unsharpness around the periphery of an image.

True