9. Recorded Detail Flashcards
is one of the 2 geometric
properties of image quality.
Recorded detail
is the degree of geometric
sharpness or accuracy of the structural lines
actually recorded in the image.
Recorded detail
Recorded detail is also referred to as
definition, sharpness, spatial resolution or simply detail
is usually quantified and even has derived
unit.
Detail
The term _______ is applied to quantified discussions of recorded detail
spatial resolution
a radiograph typically does not show soft tissue structures
Spatial Resolution
Digital image shows not only the soft tissue but also the edge of the skin
Spatial Resolution
Giving the appearance of more detail
Spatial Resolution
The primary film/screen unit of resolution is
line pairs per millimeter (lp/mm) or cycles per mm
is composed of
pairs of lines a set distance from one another
radiographic resolution tool
Digital imaging recorded detail is more commonly called
spatial resolution
is determined primarily by matrix size, pixel size,
and gray scale bit depth
Digital imaging recorded detail
is usually discussed as high or low
Spatial frequency
Shorter wavelength signal (with higher frequency) represents pairs of lines that can be visualized ______
very close together
Low frequency spatial resolution as this signal has longer wavelength (and lower frequency) representing pairs of lines that are \_\_\_\_\_\_
further apart
____ radiographic images have less recorded detail
than the object itself
ALL
Describes the ability of an imaging system to accurately
display objects in two dimensions.
Spatial Resolution
Higher when 2 objects can be demonstrated to be smaller or closer together
Spatial Resolution
Spatial resolution for digital images can be expressed in terms of _______ of the image
three dimensions
Most medical images use a _______ region of interest in the human body BUT these images contain _______ of information.
two-dimensional,
three-dimensions
high spatial resolution
represents a high-frequency signal that is capable of imaging _____ objects
smaller
Low spatial resolution represents a lower
frequency signal that can only image _____ objects
large
is simply background
information that the image receptor receives
Imaging noise
refers to a lack of sufficient incoming data for processing
Quantum Noise
the phenomena, Quantum Noise, is also called
Quantum Mottle
The solution to the problem (Quantum Mottle/Noise) remains the same – increase the number of incoming signals, whether it requires increasing the
_____ of an x-ray beam (the most common solution).
mAs
affects the image appearance by
demonstrating fine detail structures, often very
close to the size limits of the naked eye
Resolution
is often not perceived by the beginning student, partially because students
must learn to critically examine each image in a
methodical manner
Motion unsharpness
the primary
factors affecting the recorded detail of digital
imaging systems are the
Detector geometric properties and
Image processing system
detector geometric
properties and the image processing system
Digital Image Receptor Systems
Photostimulable phosphor systems are often called
Computed Radiography (CR)
have recorded detail limitations very similar to
film/screen intensifying screen phosphor systems.
Photostimulable phosphor systems
The major factors that limit photostimulable phosphor systems are the
Intensifying screen and
Scanning system
Affects recorded detail because it fails to permit
enough time for a well-defined image to form
Motion
under the direct control of the patient.
Voluntary Motion
For all patients (children and incognizant adults
may be expected in some cases), _______ is
the best method of controlling voluntary motion
communication
is not under the control of
the patient
Involuntary Motion
Difficult to detect
Equipment Motion
best method of reducing motion is
Patient communication
When the patient is unable to cooperate, the best method is a reduction in _____ with a corresponding increase in _____ to maintain sufficient mA and film density
exposure time,
mA
Other methods of decreasing exposure time while maintaining exposure include:
using a higher speed film and screens,
decreasing SID and increasing kVp
When communication and
exposure time reduction are not sufficient to
reduce motion
Immobilization
Last resort, human immobilizers may be used to hold the patient in position
- ) Male relatives
- ) Female relatives
- ) Nonradiology hospital personnel
- ) Nonprofessional radiology personnel
mA increase
Density, Contrast, Resolution, and Distortion- Maintains
kVp increase
Contrast- Decreases
Density, Resolution, and Distortion- Maintains
Film/Screen Speed Increase
Resolution- Decreases
Density, Contrast, and Distortion- Maintains
SID decreases
Density and Contrast- Maintains
Resolution- Decreases
Distortion- Increases
