Blurred Image Radiography Error Assignment
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Blurred Image Radiography Error Assignment Tinh Van Huynh & Yuezhen Xu
Dental Hygiene Program, Oxford College
DH230: Dental Radiography Theory
Instructor: Ms. Nipa Parikh
Oct 26, 2023
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The sharpness of an image is define as detail, resolution, or definition; refers to the capability of the receptor to reproduce the dinstinct outlines of an object. In other words, how well the smallest details of an object are reproduced on a dental image. Lack of sharpness, or unsharpness is aslo known as blurred image. The dental image present in fuzzy, unclear area that surrounds a tooth or sturcture on an image is termed penumbra; from the latin pene, meaning “almost,” and umbra, meaning “shadow” (
Iannucci and Howerton, 2022)
. The penumbra is the zone of unsharpness along the edge of the image; the larger it is, the less sharp the image will be.
The sharpness of the image depends on multiple factors. The first factor is the focal spot size. It is made by the manufacturer as small as possible based on heat production but still has some sizes. The x-ray is produced and released in all directions as a diagonal and passes the object is the teeth. Each different point on the focal spot will cause shadows on different spots of the receptor; it happens the same at the other side of the focal spot. It means there are many shadows appearing on the receptor. On the receptor, so many shadows are created at different areas on the receptor; the areas that are blurred is known as penumbra (Kueh et. al., 2016). The ideal image is sharpness, fine contour, clear boundaries and seeing the smallest elements of an object. Therefore, the bigger focal spot makes the bigger penumbra due to the diagonals passing the object and reaching the receptor (Figure 1).
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The second factor is source-object distance and object-receptor distance. Compare the two diagrams in figure 2, if the distance from the object to receptor is unchanged, when the target is closer to tooth, the penumbra is larger. If the target is moved farther from the tooth, the penumbra is smaller and creating a sharper image (
Jaynes, n.d). The distance of the object and receptor also affects the blurriness. When moving the object closer to the receptor, the penumbra decreases and also the magnification occurs less (Figure 2).
The third significant factor is film composition which determines image sharpness; as it is directly influenced by the size of the crystals within the film emulsion. Film used in dental radiograph is similar to photographic film, the more small pixels the more detailed the picture is;
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more of the smaller crystals the sharper the radiograph (Figure 3). However, the smaller the crystal the slower the film speed. This phenomenon occurs because larger crystals are less effective at outlining objects compared to their smaller counterparts, leading to unsharpness in the image. Hence, faster film with larger crystals result in reduced image sharpness, while the slower film with smaller crystals improved image sharpness (
Iannucci and Howerton, 2022).
The fourth factor is movement, any motion from the tubehead, receptor, or patient during x-ray exposure can lead to a reduction in image sharpness. Client movement is the most common
cause of this error. Even minimal movements can result in unsharpness, leading to the image being non-diagnostic. The last factor is focal trough in panoramic radiograph, which serves as the guideline for positioning dental arches to capture the clearest image. Focal trough is known as an image layer that represents a three dimensional curved zone. Structures in this zone appear well defined, narrow in the anterior region and wider in the posterior area. Any incorrect positioning such as teeth placed too forward or too backward from the groove in the bite-block, the result of the image is blurred in the anterior teeth area on the radiograph. To prevent these errors, the dental radiographer must position the patient’s anterior teeth are in an end-to-end position in the groove
on the bite-block, the forehead support must be adjusted to stabilize the patient’s head position
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and prevent the patien from sliding forward or backward on the bite -block (
Iannucci and Howerton, 2022)
.
Sharpness is considered a significant factor in determining image quality as it is the factor
that determines the amount of detail an imaging system can reproduce. Unsharpness or blurred images which can not be diagnostic need to be retaken. This results in additional exposure of the patient to radiation, it must be avoided at all times. Proper technique and patient preparation are very important for avoiding radiography errors and x-ray reexposure in order to keep radiation exposure “as low as reasonably achievable” (Iannucci and Howerton, 2022).
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References
Kueh, A., Warnett, J. M., Gibbons, G. J., Brettschneider, J., Nichols, T. E., Williams, M. A., & Kendall, W. S. (2016). Modelling the penumbra in Computed Tomography1. Journal of X-ray science and technology
, 24
(4), 583–597. https://doi.org/10.3233/XST-160576
Iannucci, J. M., & Howerton, L. J. (2022). Dental radiography: Principles and techniques
. Elsevier. Jaynes, R. M. (n.d).
Image Characteristics projection Geometry. Slideshare.net. https://www.slideshare.net/PARTHPMT/radiologyimagecharacteristics
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Critical Thinker and Professional Communication Rubric
a) Critical thinker written/ppt.
report
(70% of overall evaluation)
Grade Range
Indicators
Extensive
Indicators of
Criteria
(90-100%)
- evidence that data collected was relevant and broad in scope
- complete, clear and concise written/ppt. presentation
- all roles of the Dental Hygienist listed have been addressed
- all possible correction options were given for the assigned error
- demonstrates very effective written/ppt. communication
- written/ppt. presentation ensures: that knowledge can be integrated into
practice environment easily
- research content has correct formatting, 3 reputable sources, APA citation
Substantive
Indicators of
Criteria
(80-89%)
- evidence that data collected was comprehensive
- clear and concise written/ppt. presentation but missing one or more key areas
- most roles of the Dental Hygienist listed have been addressed
- most possible correction options were given for the assigned error
-
demonstrates good written/ppt. communication
- presentation ensures that knowledge may be integrated into practice
environments, but with one or more errors or omissions
- research content has mostly correct formatting, 3 reputable sources, APA
citation
Solid
Indicators of
Criteria
(70-79%)
- basic data collection results
- written/ppt. presentation which is not clear and/or missing
one or more key areas
- some roles of the Dental Hygienist listed have been addressed
- minimal correction options were given for the assigned error
- demonstrates minimal written/ppt. communication
- presentation questions if knowledge can be integrated into practice
environments, as there are many errors or omissions
- research content has little formatting, 2 reputable sources, APA citation
Criteria not
met
(less than 70%)
- data collection was limited
- written/ppt. presentation is not complete, unclear or missing many areas
- minimal or no roles of the Dental Hygienist listed have been addressed
- no correction options were given for the assigned error
- demonstrates ineffective written/ppt. communication
- presentation that knowledge could be integrated into practice environments
was not evident
- research content has no formatting, 1 or less reputable source, wrong citation used
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b) Professional Oral Communication presentation
(25% of overall evaluation)
1=70% or less
2=70-79%
3=80-89%
4=90%or greater
Criteria
1
2
3
4
Comments
Presentation:
- presentation clarity
- good speaking tone
- loud enough to be heard
- ability to hold attention of
class
- added information (did not
just read from slides)
Use of visual aids:
- diagrams
- radiographs
- props
- photos
Organization:
- clarity of information
- information is relevant and
articulate
- all important factors of
error are covered
* appearance
* cause
* how to rectify
- logical sequence followed
- correct length
(5-10 minutes)
Written/PPT. Report
/70
Spelling, Grammar- ½ mark deducted per error
/ 5
Oral Communication
/25
TOTAL MARK
**ANY FORM OF PLAGIARISM WILL
RESULT IN A MARK OF ZERO ON THIS ASSIGNMENT**
/100