X-ray Physics Exam 2

Radiographic/Optical Density specifically refers to the overall blackening of the finished radiograph, while Contrast, Resolution, and Noise are not directly related to the blackening of the image.

A film that is too dark with high optical density is often a result of overexposure, meaning that too much light reached the film during the photographing process.

The term 'under exposed' refers to film that is too light and has a low optical density, typically due to not receiving enough light during the exposure process.

The correct answer is Milliamperage and Time because they directly influence the amount of radiation produced during exposure, which in turn affects density in radiographic imaging.

Density is influenced by various factors including kVp (kilovoltage peak), SID (source-to-image distance) and collimation which affect the overall exposure and contrast in radiography.

When the mAs is increased, the quantity of radiation is increased since mAs directly affects the amount of radiation produced. Additionally, as the quantity of radiation increases, the optical density also increases as more radiation is being absorbed by the film, resulting in a darker image.

When adjusting mAs due to density errors in x-rays, a factor of 2 is used to either double or halve the mAs depending on the error observed.

The effect of kVp on density is not directly proportional. Changes in kVp can affect density but the relationship is not a simple direct proportionality.

When increasing kVp, the energy of the X-rays increases, which leads to greater penetration of the beam and ultimately increased density on the image receptor.

The 15% rule in radiology suggests that adjusting the kilovoltage peak (kVp) by 15% will have a similar outcome on the image density as doubling or halving the milliampere-seconds (mAs), depending on whether the kVp is increased or decreased.

When adjusting the density of an X-ray image, the correct parameter to use is the milliampere (mA), not the kVp.

The inverse square law states that the intensity of the x-ray beam decreases as the square of the distance from the source increases. This means that the farther away from the source you are, the less intense the x-ray beam will be.

The film-screen speed system is designed to be more sensitive to density as the speed increases, allowing for better image quality and lower radiation exposure to patients.

Radiographic contrast is the result of the differences in x-ray attenuation between structures within the subject being imaged (subject contrast) as well as the characteristics of the film used to capture the image (film contrast). Other factors like tube current, exposure time, detector sensitivity, pixel size, collimation, and grid ratio influence image quality but are not specifically related to radiographic contrast.

In radiography, kVp (kilovoltage peak) is the primary factor that controls contrast by determining the energy level of the x-ray beam.

The correct influencing factors of contrast in radiology imaging are Grids, Collimation, and OID. Factors like mAs, Focal Spot Size, and kVp do not directly influence contrast but may affect other aspects of the image quality.

In radiology, it is important to understand that high kVp settings create more densities with greater differences between them, while low kVp settings produce fewer densities but with more noticeable differences.

High kVp settings in radiography result in an image with a long scale of contrast and lower contrast levels.

Low kVp settings result in shorter wavelength x-rays which are absorbed by high atomic number materials like bone, leading to higher contrast images.

When using low kVp settings, the resulting densities are fewer but with greater differences between them compared to higher kVp settings.

Collimation refers to the process of restricting the size of the x-ray beam to the area of interest. Less collimation will result in more scatter radiation reaching the image receptor, thus reducing contrast in the image.

In radiology, penumbra refers to the blurred area surrounding the edges of an anatomical structure in a radiograph. Shadowing, contrast, and artifacts do not specifically refer to this phenomenon.

Penumbra in x-ray imaging refers to the area of unsharpness around the edges of an object. It is greatest on the cathode side of the film due to the focal spot size and shape.

Penumbra refers to the region where light and shadow blend together, causing the edges of the film to be geometrically unsharp. Halation is the spread of light beyond its proper boundaries. Vignetting is the darkening or desaturation of image corners or edges. Astigmatism causes distortion in the shape of an image.

An increase in focal spot size actually leads to a decrease in sharpness because it results in greater divergence of x-ray photons, causing unsharpness in the image.

Increasing the Source-to-Image Distance (SID) leads to a decrease in unsharpness and an increase in recorded detail due to the reduction of geometric unsharpness as a result of increased divergence of X-ray beams.

Increasing the OID (Object to Image Distance) in radiography leads to an increase in unsharpness, which results in a decrease in recorded detail on the image. This relationship is crucial in radiographic imaging techniques.

Decrease in the film screen speed system actually leads to a decrease in unsharpness and an increase in recorded detail due to faster system speeds being able to capture more detail.