Question 1

What is the primary controlling factor for radiographic contrast in analog imaging?

Accepted Answer

Kilovoltage (kV) is the primary controlling factor for radiographic contrast in analog imaging, as it affects the penetrating power of the x-rays and the differential absorption in tissues.

Question 2

Short scale contrast (in the analog image) is the result of:

Accepted Answer

Short scale contrast is the result of low kV, which produces a narrower range of densities between the black and white areas on the image. This creates a high contrast image with sharp distinctions between different tissue types.

Question 3

Which of the following changes will improve spatial resolution?

Accepted Answer

Decreasing OID (object-to-image receptor distance) will improve spatial resolution as it reduces the amount of magnification and geometric blur. Decreasing SID (source-to-image receptor distance) will have the opposite effect by increasing magnification and geometric blur. Decreasing kV may increase contrast, but it will not directly improve spatial resolution.

Question 4

Exposure time is usually expressed in units of:

Accepted Answer

The answer of Exposure time is usually expressed in units...

Question 5

Increasing the SID to 48 inches (123 cm) from 40 inches (102 cm) and adjusting the mAs accordingly will:

Accepted Answer

Increasing the SID and adjusting mAs accordingly with the use of a small focal spot will decrease penumbra, which refers to the blurriness or fuzzy edges of the image. The increase in SID will result in less divergence of the x-ray beam, and the use of a small focal spot will create a sharper image. This will not affect patient skin dose or internal dose significantly.

Question 6

The amount of blackness seen on a processed radiograph is called:

Accepted Answer

The amount of blackness seen on a processed radiograph is called density. Density is affected by the amount of radiation that reaches the film, and it is determined by the overall time and intensity of exposure. Factors such as the thickness of the object being imaged, the type of material used for the object, the size of the radiation beam and the distance from the radiation source will also affect the density of the radiograph.

Question 7

A radiograph of the hand is underexposed and nondiagnostic.The following analog (film-screen) exposure factors were used: 50 kV, 2 mAs, 40-inch (102 cm) SID.Which of the following sets of exposure factors should be used during the repeat exposure?

Accepted Answer

The radiograph is underexposed, so we need to increase the exposure. The kV and SID can stay the same because they will not affect the exposure as much as the mAs. Increasing the mAs will increase the exposure, making the image less underexposed. Therefore, the best choice is D, which doubles the original mAs value to 4 mAs. Option A increases mAs too much, and option B decreases it too much. Option C also changes the kV, which is unnecessary in this situation.

Question 8

Highly complex mathematical formulas applied during digital processing of the image are termed:

Accepted Answer

Highly complex mathematical formulas applied during digital processing of the image are termed algorithms. Pixels are individual points of color that make up an image. Digital filters are algorithms applied to images to modify their properties. Matrices are arrays of numbers used in mathematics for various operations. However, in the context of image processing, algorithms are the most appropriate choice.

Question 9

Which of the following is NOT one of the four image quality factors of an analog radiograph?

Accepted Answer

The four image quality factors of an analog radiograph are contrast, spatial resolution, distortion, and film/screen processing. Source image receptor distance (SID) does not affect image quality, but it does affect size and magnification.

Question 10

What is the most effective method to reduce the production of scatter radiation?

Accepted Answer

Collimation is the most effective method to reduce scatter radiation. By adjusting the collimators to limit the size of the x-ray beam to just the area of interest, scatter radiation is reduced. This improves the quality of the image by decreasing the amount of scattered radiation that can interfere with the formation of the image. Increasing kV and mAs can result in increased scatter radiation, and while using a grid can help reduce scatter radiation, collimation is more effective.

Question 11

Each digital image is two dimensional and is formed by a matrix of:

Accepted Answer

A digital image is a two-dimensional representation of an object or scene formed by a matrix of tiny elements called pixels. Each pixel represents a single color or shade, and together they form the overall image. The other options, bytes, algorithms, and voxels, are all related to digital images, but do not correctly describe the basic structure of an image matrix.

Question 12

A ____% increase in kV will increase density the same as doubling the mAs (analog imaging).

Accepted Answer

A 15% increase in kV will increase density the same as doubling the mAs in analog imaging. This is known as the 15% rule in radiography.

Question 13

The unsharp edge of the projected image is termed:

Accepted Answer

The unsharp edge of a projected image is termed as penumbra. This is because it is an area of partial shadow or blurred outline surrounding the darker shadow (umbra) of an object. Distortion refers to any alteration or deformation of the image, edge loss is a term used for the loss of image detail at the edges of a frame, and margin distortion is not a commonly used term in relation to projected images.

Question 14

Which of the following controlling factors will most affect radiographic resolution?

Accepted Answer

Focal spot size is the controlling factor that affects radiographic resolution the most. A smaller focal spot size produces a sharper image with greater detail and better resolution, while a larger focal spot size produces a less sharp image with lower detail and lower resolution. Therefore, it is necessary to select the smallest possible focal spot size that can provide adequate radiation output for the examination. The other factors listed, such as kV, mAs, and filtration, can also affect radiographic quality, but they do not have as direct an impact on resolution as focal spot size.

Question 15

A radiograph of the abdomen is underexposed and must be repeated.The original analog exposure factors used were 65 kV with 25 mAs.The technologist decides to keep the mA at the same level but change the kV to increase radiographic density.How much of an increase is needed in kV to double the density?

Accepted Answer

To double the radiographic density, we need to use the inverse square law: if we keep the mA constant (25 mA), doubling the density requires quadrupling the mAs (50 mAs). Since we want to keep the mAs constant, we can double the density by doubling the exposure time or doubling the radiation intensity. Doubling the radiation intensity requires increasing the kVp by 15% or 10 kV (according to the 15% rule). Therefore, we need to increase the kV from 65 to 75, which is an increase of 10 kV. Choice B is the only option close to this value.

Question 16

Which of the following radiographic studies would best benefit by applying the anode heel effect?

Accepted Answer

The anode heel effect is most beneficial for radiographic studies that involve a varied thickness of the anatomical structures being imaged. The thoracic spine has varying thicknesses due to the vertebral bodies, which makes it an ideal candidate for benefiting from the anode heel effect. The hand and ribs are thin structures, and the skull is relatively uniform in thickness, so the anode heel effect would not be as significant for these studies.

Question 17

Which of the following devices can be used rather than applying the anode heel effect to compensate for anatomic part thickness differences?

Accepted Answer

Compensating filters can be placed over the thinner part of the anatomy to balance out the radiation beam and help prevent overexposure to the thicker part, eliminating the need for the anode heel effect. Copper filters, graded screens, and added filtration do not address anatomic part thickness differences in the same way as compensating filters.

Question 18

What type of radiographic contrast is produced with a high (120) kV technique?

Accepted Answer

A high (120) kV technique produces a low contrast, long scale (also known as wide latitude) radiographic image. This is because high kV penetrates through the anatomy more easily, causing less absorption of the x-rays and resulting in a greater range of shades of gray on the image (long scale). The low contrast means that there is less difference between the shades of gray, making it more difficult to visualize fine detail but allowing for greater visualization of the overall anatomy.

Question 19

A radiograph of the abdomen demonstrates involuntary motion caused by bowel peristalsis (involuntary contractions).Which of the following factors will best eliminate this problem during the repeat exposure?

Accepted Answer

Decreasing the exposure time will reduce the amount of time the bowel has to move, resulting in a clearer image. Decreasing the SID would increase patient dose and reduce image sharpness. Turning the patient into a prone position may help depending on the location of the bowel, but may not always be feasible or necessary. Using a higher kV will increase image contrast but will not directly address the issue of bowel peristalsis.

Question 20

Which of the following factors primarily controls radiographic density in the analog image?

Accepted Answer

mAs (milliamperage-seconds) primarily controls radiographic density in the analog image. It refers to the product of the current (amperage) and the exposure time (seconds) and determines the number of x-rays that pass through the patient and reach the film. Increasing mAs increases the quantity of x-rays and results in a darker image. kV (kilovoltage) affects contrast and penetration, while film-screen speed and OID are not relevant to radiographic density in the analog image.

Quiz 1: Terminology, Positioning, and Imaging Principles