1. Quantifying photo-stimulable phosphor (PSP) plate artifacts to determine a threshold for diagnostic hindrance
Thang T, Moayedi M, Perschbacher SE
Faculty of Dentisty, University of Toronto
October 21, 2017

2. Background PSP plates accumulate artifacts with use. new minimal
moderate
severe

3. Background Current Standard – Direct Visual Inspection subjective
keep
test plate
discard
subjective
operator-dependent

4. Aim
Determine the threshold for diagnostic hindrance due to PSP artifacts by utilizing an objective artifact metric.

5. Aim Proposed Alternative objective universal keep test plate clinical
threshold
discard
objective
universal

6. Objectives
To develop an objective metric to quantify the amount and severity of physical artifacts on PSP plates.
Compare the metric against the current standard to determine the validity of this approach for PSP plate quality assurance.

7. Methods
Radiologic Exposure
control
active
discarded
70kV, 6mA, 0.22s

8. Methods Computer Analysis Artifact Metric (arbitrary units) test image
image analysis

9. Results
least artifact
most artifact

10. Results
The computer algorithm and artifact metric reflect what is expected – an accumulation of artifact score with usage.
x = 0.06
sd = 0.11
x = 0.17
sd = 0.29
x = 2.05
sd = 2.99

11. Results
least artifact
most artifact

12. Results control active discarded least artifact most artifact
Over a quarter of the discarded PSP plates have similar or less artifact than control images.
control active discarded

13. Results
Over a quarter of the discarded PSP plates have similar or less artifact than control images.

14. Results least artifact most artifact
Over a quarter of the discarded PSP plates have similar or less artifact than control images.

15. Results
least artifact
most artifact

16. Methods Compare to Current Standard scale 1 to 5 test images20
scale 1 to 5
test images
standard images

17. Results

18. Results

19. Summary
The computer algorithm and artifact metric reflect what is expected – an accumulation of artifact score with usage.
Over a quarter of the discarded PSP plates have similar or less artifact than control images.
A threshold for "significant physical artifact" should be beyond the artifacts inherent to handling PSP plates.
Using a set of standardized images has been implemented at the faculty to guide quality assurers to which plates should be discarded.

20. Future Directions
Determining how sensitivity, specificity, and inter-/intra-examiner reliability decreases for radiologic interpretations when artifacts are present.
Creating a threshold for the artifact metric upon which radiologic interpretations are impaired
Recommend guidelines that can aid the clinician in knowing when PSP plate artifacts have exceeded the threshold and when they should be replaced.

21. References
Buchanan A, Benton B, Carraway A, Looney S, Kalathingal S. Perception versus reality—findings from a phosphor plate quality assurance study. Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology. 2017;123(4): doi: /j.oooo
Chiu H-L, Lin S-H, Chen C-H, et al. Analysis of photostimulable phosphor plate image artifacts in an oral and maxillofacial radiology department. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology. 2008;106(5): doi: /j.tripleo
Gulsahi A, Secgin C. Assessment of intraoral image artifacts related to photostimulable phosphor plates in a dentomaxillofacial radiology department. Nigerian Journal of Clinical Practice. 2016;19(2):248. doi: /

22. thanks for listening questions and comments?