Recorded Detail/Spatial Resolution Flashcards
What are other terms used for recorded detail?
Sharpness, detail, definition
Recorded Detail
The ability of a system to ___ record the ___ ___ of the object you are imaging.
Are the structural lines ___ or ___?
Recorded Detail
The ability of a system to accurately record the structural lines of the object you are imaging.
Are the structural lines sharp or blurry?
Spatial Resolution
- Ability of an imaging system to accurately display objects in ___ ___.
- With the digital image shown on a ___ this has slightly changed the ___.
- The Digital Imaging courses will go into further information for the digital images.
Spatial Resolution
- Ability of an imaging system to accurately display objects in two dimensions.
- With the digital image shown on a monitor this has slightly changed the definition.
- The Digital Imaging courses will go into further information for the digital images.
Assessing Recorded Detail
- ___ of ___
- ___ ___ Test measured in ___ per ___ (lp/mm)
- ___ ___ Test
Assessing Recorded Detail
- Unit of resolution
- Line Pairs Test Measured in lines per millimeter (lp/mm)
- Star Pattern Test
What 3 categories affect recorded detail?
- Motion
- Material(s)
- Geometric
Motion
Motion unsharpness is the most detrimental factor contributing to a lack of ___ ___ or ___.
Motion
Motion unsharpness is the most detrimental factor contributing to a lack of image definition or sharpness.
Effects on Image Appearance
Images lacking fine detail appear ___
Assessment of motion
Effects on Image Appearance
Images lacking fine detail appear blurry
Assessment of motion
What are the 3 types of motion?
- Voluntary motion
- Involuntary motion
- Equiptment motion
What can help with involuntary motion?
- Exposure time reduction
- Immobilization
You must control motion
- Explain the exam to the patient. Must take in the patient’s ___ into consideration
- How do you talk to an ___ patient vs a ___?
Use ___ devices if necessary. ___, ___, ___ ___.
You must control motion
- Explain the exam to the patient. Must take in the patient’s age into consideration
- How do you talk to an elderly patient vs a child?
Use immobilization devices if necessary. Tape, sandbags, lead aprons.
Motion
- ____ exposure time needed
- 100 MA at .10
- 200 MA at .05
- 400 MA at .025
Which would be the best to use: All factors = 10 mAs
Motion
Reduce exposure time needed
- 100 MA at .10
- 200 MA at .05
• 400 MA at .025
Which would be the best to use: All factors = 10 mAs
Motion
use a ___ speed film/screen combination if needed
Look at the ___/____ relationship if needed.
▲KVP by ___% - cut mAs in ___
- ex. 20 MAS at 60 KVP
- 400 mA at .05 sec. at 60 KVP
- 400 mA at 0.025 sec. at 69 KVP
Motion
use a higher speed film/screen combination if needed
Look at the KVP/mAs relationship if needed.
▲KVP by 15% - cut mAs in half
- ex. 20 MAS at 60 KVP
- 400 mA at .05 sec. at 60 KVP
- 400 mA at 0.025 sec. at 69 KVP
What are 3 things that can contribute to material unsharpness?
Type of film, intensifying screens, film/screen contact
Type of Film
___ speed = ___ detail (___ crystals and ___ emulsion)
___ speed = ___ detail (___ crystals and ___ emulsion)
Type of Film
Slow speed = more detail (smaller crystals and thinner emulsion)
Fast speed = less detail (larger crystals and thick emulsion)
Type/Speed of Intensifying Screens
non-screen or cardboard – ___ detail because ___ light is given off during the exposure.
Slow Screen speed = ___ detail - ___ crystals – ___ light is given off during the exposure.
___ layer - ___ detail because ___ light is given off during the exposure.
Type/Speed of Intensifying Screens
non-screen or cardboard – better detail because no light is given off during the exposure.
Slow Screen speed = Better detail - smaller crystals – less light is given off during the exposure.
Thinner layer - Better detail because less light is given off during the exposure.
Fast Screen Speed
Fast Screen speed = ___ detail (___ light is given off during the exposure)
- ___ crystals – ___ light is given off during the exposure
- Thick layer – ___ light
Fast Screen Speed
Fast Screen speed = decrease detail (more light is given off during the exposure)
- larger crystals – more light is given off during the exposure
- Thick layer – more light
Radiographic Noise
is an undesirable ___ in the ___ ___ of the image. You can have “noise” on a radiographic film, TV monitor, digital images or CT monitor.
Compare - audio and video noise as “snow”.
Radiographic Noise
is an undesirable fluctuation in the optical density of the image. You can have “noise” on a radiographic film, TV monitor, digital images or CT monitor.
Compare - audio and video noise as “snow”.
What are the 3 terms to describe radiographic noise?
Film graininess, structural mottle, and quantum mottle
Radiographic Noise
- Film graininess-refers to the distribution in ___ and ___ of the ___ ___ crystals in the ___ layer.
- Structural Mottle similar to film graininess, but it refers to the construction of the ___ layer of the ___ screens. (Both are ___ in the film/screen combinations and the radiographers has ___ control over these factors)
- Quantum Mottle - refers to the ___ nature in which x-rays interact with the ___.
Radiographic Noise
- Film graininess-refers to the distribution in size and space of the silver halide crystals in the emulsion layer.
- Structural Mottle similar to film graininess, but it refers to the construction of the phosphor layer of the intensifying screens. (Both are inherent in the film/screen combinations and the radiographers has no control over these factors)
- Quantum Mottle - refers to the random nature in which x-rays interact with the IR.
Digital – if your technique is set too ___ (___) for the particular body part = ___ image
Digital Images = Poor ___ to ___ Ratio refers to ___ IR radiation exposure (___ image).
Digital – if your technique is set too low (underexposed) for the particular body part = grainy image
Digital Images = Poor Signal to Noise Ratio refers to low IR radiation exposure (underexposed image).
As a General Rule:
fast image receptor have ___ radiographic noise and ___ resolution.
___ resolution requires ___ noise and ___ image receptors.
Digital Systems: signal to noise ratio: *___ signal – ___ noise
As a General Rule:
fast image receptor have high radiographic noise and low resolution.
high resolution requires low noise and slow image receptors.
Digital Systems: signal to noise ratio: *high signal – low noise
Film Screen Contact
___ ___ test
Film Screen Contact
Wire Mesh test
What are the 3 geometric factors?
- FSS
- OID
- SID
Distances
Distances
Focal Spot Size
___ the FSS – the ___ the sharpness of detail
Focal Spot Size
Smaller the FSS – the better the sharpness of detail
OID
You want the object of interest as ___ to the image receptor as possible (the closer, the ___).
As the OID increases, you will ___ the detail. (___)
OID
You want the object of interest as close to the image receptor as possible (the closer, the sharper).
As the OID increases, you will decrease the detail. (Magnification)
SID
Teleoroentgenography – 72” SID will be using the ___ portion of the primary beam.
“___ to size”
SID
Teleoroentgenography – 72” SID will be using the parallel portion of the primary beam.
“True to size”
What are 2 terms to describe area of unsharpness?
- Penumbra
- Umbra
Penumbra and Umbra
Penumbra is the area of ___ around the recorded ___ of the object.
Umbra is the area of ___ around the recorded ___ of the object.
Penumbra and Umbra
Penumbra is the area of unsharpness around the recorded edges of the object.
Umbra is the area of sharpness around the recorded edges of the object.
Assessing Recorded Detail
kVp and mAs doesn’t control ___ ___
Assessing Recorded Detail
kVp and mAs doesn’t control structural lines
Using the 3 geometric factors – what combination would give you the BEST detail?
- Small FSS
- Short OID
- Long SID
What is the formula for penumbra?
Penumbra = effective FSS x OID/SOD
(SID-OID= SOD)
Digital Image Receptor Systems
Image processing system ___ recorded detail
Spatial resolution is dependent on:
- ___ and ___ ___
- ___ ___
- ___ ___ ___ ___
Digital Image Receptor Systems
Image processing system limits recorded detail
Spatial resolution is dependent on:
- Acquisition and display matrix
- Pixel size
- Gray scale bit depth
Spatial Resolution
Spatial Resolution
Spatial Frequency
___ frequency signal (better)
Determined by measuring ___ between ___ of ___ distinct from one another
Spatial Frequency
High frequency signal (better)
Determined by measuring distance between pairs of lines distinct from one another
Noise
___ information received by ___ ___
Quantum noise is also called ___ ___
___ signal and ___ noise = good image
Noise
Background information received by image receptor
Quantum noise is also called quantum mottle
High signal and low noise = good image
