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RADT 465
Image Production and Evaluation
Question | Answer |
---|---|
What are visibility factors for image quality? | Density/Brightness and Contrast/Gray Scale (Saia, pg 298) |
What are geometric factors for image quality? | Detail/Resolution and Distortion (Saia, pg 298) |
What are the exposure factors? | mA, time, kV, and distance (Saia, pg 298) |
What are the types of distortion? | Size distortion(magnification) and shape distortion (elongation/foreshortening) (Saia, pg 298) |
What are factors affecting recorded detail/resolution? | OID, SID, Focal spot size, patient factors, intensifying screens, motion (Saia, pg 298) |
What are factors affecting size distortion? | OID, SID (Saia, pg 298) |
What are factors affecting shape distortion? | alignment of x-ray tube, anatomic part, and IR (Saia, pg 298) |
When does subject/object unsharpness occur? | object shape does not coincide with the shape of x-ray beam, object plane is not parallel with x-ray tube or IR, anatomic objects of interest are not in the path of the CR, anatomic objects of interest are a distance from the IR (Saia, pg 303) |
How is unsharpness/blur related to focal spot size? | Directly (Saia, pg 308) |
How is unsharpness/blur related to SID? | Inversely (Saia, pg 308) |
True or False: the use of a small focal spot improves recorded detail? | True (Saia, pg 308) |
When is the anode heel affect most pronounced? | when using large IRs, short SIDs, and small anode angles (Saia, pg 309) |
How do we minimize voluntary motion? | good communication and suspended respiration (Saia, pg 310) |
How do we minimize involuntary motion? | short exposure time, part support and stabilization, special immobilization devices (Saia, pg 310) |
What are the rare earth phosphors? | Gadolinium, Lanthanum, Yttrium (Saia, pg 311) |
What is the greatest adversary of recorded detail? | motion (Saia, pg 310) |
As intensifying screen speed increases, what else increases? | x-ray tube life (Saia, pg 313) |
As intensifying screen speed increases, what decreases? | patient dose (Saia, pg 313) |
When is quantum mottle most likely to occur? | when using fast screens with low mAs and high kV (Saia, pg 313) |
True or False: Intensifying screens are unrelated to digital imaging? | True (Saia, pg 313) |
What is responsible for more than 98% of film emulsion exposure? | fluorescent light (Saia, pg 313) |
What is the reciprocity law? | Any combination of mA and exposure time that will produce a particular mAs, will produce identical image density (Saia, pg 317) |
What describes the amount of blackening on an x-ray image or part of the image? | Density (Saia, pg 317) |
What is directly proportional to the intensity/exposure rate/number of x-ray photons produced? | mAs (Saia, pg 317) |
What are the three things that x-ray photons can do within an anatomic part? | penetrate through the part, scatter through the part, be absorbed by the part (Saia, pg 320) |
What type of grids are there? | parallel or focused and stationary or moving (Saia, pg 324) |
What are some factors of filtration? | reduces patient skin dose, minimum 2.5 mm Al equivalent, inherent x added=total filtration, increases overall average energy of x-ray beam (Saia, pg 330) |
When do we use compensation filtration? | used for anatomic parts having very different thickness/absorption properties, used to 'balance' tissue densities; improves visualization of all tissues (Saia, pg 330) |
What are examples of additive pathologic conditions? | ascites, RA, Paget disease, PNM, atelectasis, CHF, edematous tissue (Saia, pg 333) |
What are examples of destructive pathologic condtions? | osteoporosis, osteomalacia, pneumoperitoneum, emphysema, degenerative arthritis, atrophic and necrotic conditions (Saia, 333) |
What is the function of contrast? | to make details visible (Saia, pg 339) |
True or False: Digital imaging significantly improves dynamic range and contrast resolution? | True (Saia, pg 341) |