Chapter 3: Image Formation and Radiographic Quality

smaller pixel size and greater bit depth

Digital image quality is improved with:

photoelectron interaction

interaction between x-ray photons and tissue that results in production of a secondary x-ray photon is the:

pair production and photodisintegration

interactions of high energy x-rays ( beyond the diagnostic range) with tissue include:

coherent scattering

interactions of low energy x-rays (below diagnostic range) with tissue include:

True

Magnification always results in reduced recorded detail T/F

latent, manifest

the ___ image occurs on the image receptor, and the ___ image occurs following proper image development/processing

brightness

the amount of luminance of a display monitor is:

greyscale

the number of shades of gray that can be displayed by a computer system is:

secondary electron and compton electron

the outer shell electron that is ejected during the compton interaction is also known as:

density

the overall blackness on the processed film image is:

ionization

the photoelectric effect involves the removal (ejection) of an electron. this process of removing electrons is known as:

considered as separate image qualities except when imaging small objects

the sharpness of recorded detail and the visibility of recorded detail are:

remnant radiation

the x-ray beam that leaves the patient in the direction of the image receptor is often referred to as:

strike the image receptor, providing useful anatomic information

the x-ray photon that is scattered as a result of the compton effect CANNOT:

fog

unwanted exposure to the IR due to scatter radiation is called:

compton effect

when the entering x-ray photon loses energy and changes its path of travel as a result of interacting with an atom, the interaction is known as the:

absorbed, photoelectric effect

when the x-ray photon strikes an atom within the tissue being imaged and loses all of its energy to an inner shell electron of that atom, the photon is said to have been ____ and undergone the _____.

scattered, compton interaction

when the x-ray photon strikes an atom within the tissue being imaged and loses only part of its energy to an outer shell electron of that atom, the photon is said to have been ____ and undergone the___.

transmission

when the x-ray travels completely through the part, this activity is called:

False

Recorded detail is the term commonly used in digital imaging to describe the accuracy of the structural lines that make up the image

True

Shape distortion can be useful in radiographic imaging

increased pixel density

Spatial resolution is improved with:

True

The abdomen has low subject contrast T/F

False

The brightness/density and contrast of film-screen and digital manifest images can be adjusted, just in different ways.

True

The compton interaction can occur within all diagnostic x-ray energies T/F

False, there is always unshaprness

The highest quality radiographic image has no unsharpness T/F

True

The photoelectric effect is dependent on both the energy of the x-ray photon and the composition of the anatomic tissue T/F

True

The primary factor that affects film-screen density is the quantity of radiation reaching the IR T/F

increase in noise on the radiographic image

What indicates greater quantum mottle, is more likely with digital imaging than with film-screen, and is the result of fewer than appropriate x-ray photons reaching the IR?

lighter (less density)

With film- screen imaging, anatomic tissues, such as bone, that absorb most of the radiation result in that area of the image being:

False

X-ray absorption is more likely in tissues with a lower atomic number T/F

all of the above

a film image with a large number of similar densities: has long scale contrast, has low contrast, appears gray, or all of the above

fewer, increased

at high kilovoltage, the ___ photon interactions occur, resulting in ___ transmission

visibility of structures

brightness/ density is a quality related to the ___ of the radiographic image

jewelry, fog, quantum noise

common artifacts to both film-screen and digital imaging include:

visibility of structures

contrast is a quality related to the ___ of the radiographic image

image contrast

difference in the brightness levels or densities is:

increases contrast resolution

A larger bit depth:

increases the number of shades of gray

A larger bit depth:

True

An area of increased brightness on a display monitor will show decreased density on a film image T/F

is lighter than the surrounding image

An artifact that is classified as minus-density:

False, 5%

Approximately 20% of the primary x-ray beam actually reaches the image receptor T/F

False

Beam attenuation is increased with a higher energy x-ray beam T/F

False, totally independent of matrix size

Bit depth is determined by the matrix size

False

Compton interactions are more likely to occur in soft tissue as compared to bone T/F

narrow dynamic range

Due to its _____, repeats are often needed with film-screen imaging, because the image is too dark or light

True

Quantum noise is significantly more likely with digital imaging

True

Radiographic images of structures are always magnified when compared to the actual structure

unacceptable

an image that has excessive brightness or insufficient density is considered:

artifact

an unwanted image on a radiograph:

decreases the visibility of anatomic structures

as seen on the radiographic image, scatter radiation:

attenuation

loss of some of the energy from the x-ray beam as it passes through the tissue being imaged

higher tissue density

muscle tissue absorbs more radiation than fat tissue because muscle tissue has a:

magnification, elongation, foreshortening

radiographic misrepresentation of the size or shape of the anatomic structure being imaged is:

4 to 5 cm

remnant radiation will be reduced be one half for every additional ____ of part thickness

differential absorption

results in the process of image formation, whereby the x-ray beam interacts with the anatomic tissue, and a portion strikes the image receptor

elongation

shape distortion includes:

SID and OID

size distortion is affected by:

energy of the x-ray beam and absorption characteristics of the tissue being imaged

subject contrast is dependent on the: