Introduction and Principles Flashcards
When primary x-ray beam passes through the patient, it undergoes a process of what?
Attenuation
When x-ray beam passes through the patient, it is attenuated in different amounts depending on what?
Density of tissue through which is has passed
Object tissue radio density includes?
Air Fat Water Bone/Calcific Metal
What is the order of object radiodensity starting with the most lucent and going to the most opaque?
Air–>Fat–>Water–>Bone–>Metal
What is the amount of blackness on the radiograph?
Radiographic Density
There is an inverse relationship between what?
Radiodensity of an object and radiographic density on radiograph.
Thick tissue causes what radiographic density?
Less (white/opaque)
Thin tissue causes what radiographic density?
More (black/lucent)
Radiographic density is primarily controlled by?
mAs
mAs control the amount of x-rays quanta (bundles) emitted from the x-ray tube during?
Exposure
mAs is what type of factor?
Quantitative Exposure
What is the amount of difference between black and white on a radiograph?
Radiographic Contrast
What is the purpose of contrast?
Make anatomic detail more visible
In skeletal radiograph high contrast is often required to visualize what?
Cortical margins of bone clearly
What is the primary controlling factor for contrast?
Peak Kilovoltage (kVp)
The kVp is the factor which controls the energy of the electrons as they move across the tube, or the speed of the electrons, thus controlling what?
Beam Quality
What does kVp equal?
Quantitative exposure factor
What is the main determinant of beam quality?
kVp
What control the number of electrons and therefore radiographic density (overall blackness or whiteness)?
mAs
kVp controls the speed of the electrons and therefore beam quality which relates to what?
Film Contrast (difference btwn shades)
kVp influences necessary what?
mAs
What is the primary controlling factor of radiographic definition?
Motion
How does motion affect definition?
Insufficient time for an image to form
Radiographic definition is affected by what?
Motion
Beam Size
Distances
What is the difference between the actual object and it’s recorded image?
Radiographic Distortion
What are the 2 types of radiographic distortions?
Size
Shape
The further the tube from the image receptor, the less what?
Magnification
The closer the structure is to the image receptor, the less what?
Magnification
The larger the object, the further the outer boundaries are from the central ray, the greater the what?
Magnification of the object
What is the theoretical center of beam?
Central Ray
Shape distortion causes what?
Unequal Magnification
Only at the central ray a portion of the beam striking the structure and image receptor perpendicularly is the image what?
Close to accurate
When taking x-rays what is the minimum amount of views?
2 at 90 degrees (orthogonal views)
The 10 day rule is not justified if the delay could prove detrimental to what?
Health/welfare of pt
Frontal views are named according to?
Beam entrance-to-beam exit
Lateral views are named according to?
Which SIDE of pt’s body is closet to image receptor
Oblique views are name according to?
Which QUADRANT of pt’s body is closest to film
What are downsides to film based imaging?
Increase radiation dose Repeat exposures Time Inability to alter image Physical transport Storage space Films get lost
What are good reasons for digital based imaging?
Technical alteration of image after exposure
Better disease detection
Immediate access
Eliminate need for storage and inventory cost
Less environmental impact
Improved archival quality of images
What are downsides to digital based imaging?
Non-reusability and Cost
Quality Control
Anterior OBL demonstrates what?
Ipsilateral IVF
Posterior OBL demonstrates?
Contralateral IVF
