Evaluation of the Effect of Light and Scanning Time Delay on The Image Quality of Intra Oral Photostimulable Phosphor Plates

Amir Eskandarloo1, Arman Yousefi2, *, Setareh Soheili3, Karim Ghazikhanloo4, Payam Amini5, Haniyeh Mohammadpoor6
1 Department of Oral and Maxillofacial Radiology, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran
2 Department of Oral and Maxillofacial Radiology, Dental School, Ardabil University of Medical Sciences, Ardabil, Iran
3 Department of Pediatric Dentistry, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran
4 Department of Medical Physics, Paramedical school, Hamadan University of Medical Sciences, Hamadan, Iran
5 Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
6 Private practice, Kelachai, Iran

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Creative Commons License
© 2017 Eskandarloo et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Oral and Maxillofacial Radiology, Dental School, Hamadan University of Medical Science, Fahmideh Street, Hamadan, Zip Code: 38677-65178; Iran; Tel: 00989128238490; E-mail:



Nowadays, digital radiography is widely used in dental practice. One of the most common types is Photo Stimulated Phosphor Plate (PSP).


The aims of this experimental study were to evaluate the impacts of different combinations of storage conditions and varying delays in reading of digital images captured using PSPs.


Standardized images of a step wedges were obtained using PSPs from the Digora digital systems. Plates were exposed and immediately scanned to produce the baseline gold standard. The plates were re-exposed and stored in four different storage conditions: white light, yellow light, natural light environment and dark room, then scanned after 10 and 30 minutes and 4 and 8 hours. Objective analysis was conducted by density measurements and the data were analyzed statistically using GEE test. Subjective analysis was performed by two oral and maxillofacial radiologists and the results were analyzed using McNemar’s test.


The results from GEE analysis show that in the natural light environment, the densities in 10 minutes did not differ from the baseline. The mean densities decreased significantly during the time in all environments. The mean densities in step 2 for the dark room environment decreased with a slighter slope in comparison to yellow environment significantly.


PSP images showed significant decrease in the density in plates scanned for 10 minutes or longer after exposure which may not be detected clinically. The yellow light environment had a different impact on the quality of PSP images. The spatial resolution did not change significantly with time.

Keywords: Contrast, Spatial resolution, Photostimulable phosphor plates, Digital image, Environmental light, Density.