Physics Chapter 26 and 27 quiz

Which generator type produces the least amount of receptor exposure per mAs? a. single-phase, 2-pulse b. three-phase, 6-pulse c. three-phase, 12-pulse d. a high-frequency generator

a. single-phase, 2-pulse

Image receptor contrast of radiographic film is expressed as the ____ of the D log E curve a. slope b. toe c. shoulder d. speed

a. slope

Which rule is used as a guide to maintain the same receptor exposure when kVp changes? a. doubling rule b. 15% rule c. inverse square rule d. density maintenance law

b. 15% rule

The minimum charge necessary to improve the appearance of noise on a digital image is ______ percent of mAs a. 10-12 b. 25-35 c. 50-60 d. none of the above

b. 25-35

kilovoltage peak kVp controls the proportional relationship of a. mAs and kVp b. Compton and photoelectric interactions c. photoelectric and characteristic interactions d. SID and patient thickness

b. Compton and photoelectric interactions

Which statement is TRUE? a. as mAs increases, scatter decreases b. as mAs decreases, quantum noise can appear c. as mAs increases, remnant radiation decreases d. as mAs decreases, exposure increases logarithmically

b. as mAs decreases, quantum noise can appear

the total amount of irradiated material is a function of a. tissue thickness and tissue density b. body part thickness and area of exposure c. field size and anode angle d. body position and focal spot size

b. body part thickness and area of exposure

When changing your SID from 72" to 56" a. decrease your kVp by 15 percent b. decrease your mAs by 50 percent c. increase the mAs by a factor of 4 d. increase the kVp by 15 percent

b. decrease your mAs by 50 percent

Digital image artifacts such as vertical or horizontal lines, opaque, white lines demonstrates a. underexposure b. excessive exposure c. quantum noise d. system noise

b. excessive exposure

A radiograph with a few shades of gray exhibits a. low contrast b. high contrast c. medium contrast d. long scale contrast

b. high contrast

Focal spot blooming occurs with a. high kVps b. high mA exposures c. large SIDs d. extreme tube angulation

b. high mA exposures

With digital imaging systems, the primary factors affecting final image contrast are the a. window level and brightness b. histogram and look-up table (LUT) c. EI numbers and S numbers d. kVp and mAs

b. histogram and look-up table (LUT)

All of the following will decrease digital receptor exposure except a. increased grid ratios b. increased beam angulation from 5 degrees to 10 degrees c. increased OID d. increased filtration

b. increased beam angulation from 5 to 10 degrees

Which of the choices below does not increase contrast a. increasing grid ratio b. increasing the amount of irradiated tissue c. decreasing filtration d. decreasing kVp

b. increasing the amount of irradiated tissue

all of the following factors would affect radiographic subject contrast EXCEPT a. part thickness b. average tissue density c. using barium as a contrast agent d. LUT selection

d. LUT selection

The brightness of the image on a viewing monitor is a. the result of receptor exposure b. the result of tissue density c. the result of the tissue thickness d. a function of the monitor

d. a function of the monitor

Which generator produces the greatest amount of receptor exposure per mAs? a. single-phase, 2-pulse b. three-phase, 6-pulse c. three-phase, 12-pulse d. a high-frequency generator

d. a high-frequency generator

A change in kVp, as an exposure factor, affects a. average beam energy b. beam intensity c. the amount of scatter production d. all of the above

d. all of the above

A radiograph that demonstrates considerable differences between gray shades is said to have a. short scale b. high contrast c. increased contrast d. all of the above

d. all of the above

A radiograph that demonstrates minimal differences between gray shades is said to have a. long scale b. low contrast c. decreased contrast d. all of the above

d. all of the above

Optimum exposure to a digital detector system a. varies between manufacturers b. is a function of acceptable noise levels c. is identified with target exposure index values d. all of the above

d. all of the above

an increase in x-ray beam filtration a. increases the number of Compton interactions b. reduces contrast c. increases the average photon energy d. all of the above

d. all of the above

The anode heel effect is pronounced with a. smaller field sizes (8"x10") b. stationary anodes c. a 10-degree target angle d. rotating anodes

c. a 10-degree target angle

when digital imaging receptors are used a. kVp is not a consideration b. radiographic grids are not necessary c. an exposure at 90 kVp would require a grid d. Compton scatter is not a factor

c. an exposure at 90 kVp would require a grid

The effect of mAs upon IR exposure is a. inverse b. inversely proportional c. directly proportional d. dependent upon kVp

c. directly proportional

selecting an open-mouth odontoid LUT and applying this LUT to a KUB will yield a final image with a. low contrast and reduced visibility of detail b. many subtle gray shades and a longer scale of contrast c. high contrast visualization of lumbar spine anatomy d. the look of a high kVp exposure and quantum noise

c. high contrast visualization of lumbar spine anatomy

with increasing kVp levels, it is important to remember that with digital receptors and DR technologies a. less differential absorption occurs and a narrower histogram results b. the difference between minimum and maximum incoming photon energies is reduced c. more anatomical data can be recorded with a lower patient dose d. all of the above

d. all of the above

In the event of making a single exposure that is critical to the exam success, most experienced technologists will a. use slightly less mAs than necessary to prevent overexposure b. overexpose the IR slightly c. provide enough exposure to create an adequate histogram or permit viewing a film with a bright light d. both b and c

d. both b and c

Moderate increase in kVp with a digital receptor will produce a. dramatic changes in image contrast b. a change in entrance skin exposure c. no change in image brightness d. both b and c

d. both b and c

The relationship between exposure and SID is a. directly proportional b. inversely proportional to the cube of the distance c. directly proportional to the square of the distance d. inversely proportional to the square of the distance

d. inversely proportional to the square of the distance

Which type of radiograph provides the most clinical information a. an image with quantum mottle b. short-scale contrast images c. low-density images d. low-contrast images

d. low-contrast images

what should you expect to occur with a decrease in kVp, using digital receptors a. an increase in Bremsstrahlung tissue interactions b. more Compton interactions c. a narrower histogram d. more photoelectric interactions

d. more photoelectric interactions

The 15% rule will affect a. recorded detail b. image brightness c. distortion d. none of the above

d. none of the above

Assessment of digital radiographic image quality includes a. looking at the window/level values on the monitor b. electronic masking the image to improve the exposure indicator value c. postprocessing the image to enhance image contrast d. referencing exposure indicators values for acceptance

d. referencing exposure indicators values for acceptance

In digital imaging using a DR detector, image contrast decreases with a. excessive kVp values b. underexposure c. mAs values that are too low d. radiographic grids

a. excessive kVp values

When the tissue structure of the ankle joint is considered, the dramatic tissue differences between the muscles and bones of the ankle produce a. high subject contrast b. low subject contrast c. high receptor contrast d. low receptor contrast

a. high subject contrast

As kVp ____, a ____ range of photon energies is produced. a. increases; wider b. increases; narrower c. decreases; wider d. decreases; longer

a. increases; wider

Because of the "heel effect", x-ray beam intensity a. is greater under the cathode side of the tube b. is greater under the anode side of the tube c. is equal across the beam long axis d. changes with patient position

a. is greater under the cathode side of the tube

The principal controlling of radiographic contrast using film-screen technology is a. kVp b. mAs c. focal spot size d. anode angle

a. kVp

Which factor influences the average energy of photons reaching the IR? a. kVp b. mAs c. focal spot size d. mA

a. kVp

What conclusion can you reach regarding an image with an S# of 750 and good image brightness on the display monitor? a. the image is likely to demonstrate noise or quantum mottle b. there was not enough exposure to create a good histogram c. the noise level will be at a minimum and the image will look good in the magnification mode d. the IR received too much exposure

a. the image is likely to demonstrate noise or quantum mottle

High contrast is directly related to a. the number of photoelectric interactions b. high kVp c. the amount of Compton scatter d. mAs

a. the number of photoelectric interactions

Immediately after exposure and before a digitally acquired image is post-processed, the initial image shown demonstrates a. very low contrast b. the heel effect c. focal spot blur d. extremely high contrast

a. very low contrast

Image brightness on an image display monitor is controlled by a. window level b. window width c. EI number d. S number

a. window level

In order to reduce patient entrance skin exposure (ESE), higher kVp exposures are a consideration. It is important to remember that? a. kVp values that are too high can short-circuit a digital detector b. kVp values that are excessively high can negatively impact the data histogram c. a significant loss of image contrast is not a reason to avoid higher kVp values in order to reduce ESE d. the digital processing software will correct for any kVp value regardless of how high it is in value

b. kVp values that are excessively high can negatively impact the data histogram

A frontal projection chest radiograph that demonstrates a faint outline of the thoracic spine and many shades of gray to show the pulmonary markings of the lungs illustrates a. underpenetration b. long-scale contrast and adequate penetration c. overpenetration d. short-scale contrast and adequate penetration

b. long-scale contrast and adequate penetration

The principal controlling factor of radiographic receptor exposure is a. kVp b. mAs c. focal spot size d. filtration thickness

b. mAs

Which factor influences the number of photons reaching the IR? a. kVp b. mAs c. focal spot selection d. exposure time

b. mAs

As you analyze your image, you come to the conclusion that it must have more exposure. As a general rule, you should increase a. kVp b. mAs by 2X c. the SID d. mAs by a 0.5 multiplier

b. mAs by 2X

a radiographic grid with a K-factor of 1 would offer a. a 100 percent increase in contrast b. no change in image contrast c. a reduction in image contrast d. an increase in exposure with a decrease in contrast

b. no change in image contrast

Radiographic image contrast is a combination of a. grid ratio and field size b. receptor contrast and subject contrast c. filtration thickness and field size d. data rescaling and look-up tables

b. receptor contrast and subject contrast

when choosing between two radiographic grids, the k factor is different. Choosing a grid with the higher K factor a. produces an image with lower contrast b. results in a higher degree of scatter and secondary radiation clean-up c. will improve recorded detail d. requires a reduction in mA to compensate for the added subject contrast

b. results in a higher degree of scatter and secondary radiation clean-up

a fluoroscopic examination that uses barium as a contrast material would typically produce images with a. long scale contrast b. short scale contrast c. low contrast d. both a and c

b. short scale contrast

The recorded detail of a digital radiographic image is primarily visible because of a. sufficient contrast b. sufficient receptor exposure c. low signal to noise ration (SNR) d. both a and b

b. sufficient receptor exposure

A high contrast LUT applied to a chest radiograph would yield a. dark lung fields and poorly demonstrated lung mediastinal anatomy b. very few gray shades between the darkest and lightest regions of the chest c. underpenetrated lung fields and a clear sillhouette of the thoracic spine d. excellent visualization of the bronchopulmonary markings and ribs

b. very few shades between the darkest and lightest regions of the chest

You have completed a chest radiograph using 3 mAs @ 110 kVp. The image shows obvious under penetration of the mediastinal anatomy. The professional radiographer would a. increase kVp by 3 kVp and repeat the exposure b. use the 15% rule and reduce the kVp and increase the mAs c. increase the kVp to 120 kVp and repeat the exposure at the same mAs d. remove the beam filtration and repeat the exposure

c. increase the kVp to 120 kVp and repeat the exposure at the same mAs

as kVp increases, the percentage of Compton interactions _____ and contrast ___ a. decreases; decreases b. decreases; increases c. increases; decreases d. increases; increases

c. increases; decreases

With digital imaging technologies, the final brightness and contrast appearance of an image is due to a. kVp b. window and level controls c. look-up table (LUT) application d. image rescaling

c. look-up table (LUT) application

Radiographic room A is a three-phase, six-pulse generator. Room B is a high-frequency generator. When going between these two rooms to perform examinations, what exposure modification is necessary to produce comparable exposure density? a. use 15 percent more with the three-phase system b. use 10 percent more with the high-frequency system c. no change is required between the two systems d. use 10 percent less with the high-frequency system

c. no change is required between the two systems

The greatest factor in the production of scatter radiation is a. kVp b. mAs c. patient thickness d. patient position

c. patient thickness

The difference between two adjacent gray shades on a radiographic image is a. recorded detail b. quantum mottle c. radiographic contrast d. distortion

c. radiographic contrast

Varying tissue thickness and densities is referred to as a. differential absorption b. attenuation c. subject contrast d. image contrast

c. subject contrast

In the case of film radiography a. the response to exposure is linear b. the response to radiation exposure is inverse c. the response to exposure is logarithmic d. the response to exposure is exclusively a function of kVp

c. the response to exposure is logarithmic