Classification of Artifacts on Phosphor Plates

Objectives: Digital radiography has numerous advantages over traditional film based techniques and is gaining popularity. Indirect digital radiography using photostimulable phosphor plates (PSP) has been implemented in many US dental schools. These plates are used repeatedly and are subjected to wear and tear and as a result are presented in the forms of artifacts such as lines and blobs on the images. This study was aimed to subjectively quantify the presence of artifacts on PSP plates 9 months after implementation of digital radiography in a dental school clinic.

Methods: Seven sets of blank clinical OpTime PSPs (Soredex/ Orion Corp., Helsinki, Finland) were scanned after exposing them at 65 kV and 7 mA for 0.80s. Scanned plates were lightly wiped with a soft cloth and alcohol solution, repackaged in plastic sleeves, re-exposed, and re-scanned. The two sets of resulting images were subjectively ranked independently by two investigators for artifacts and placed in 5 categories.

Results: Of all images approximately 75% were rated in the top 3 categories (most readable), leaving 17% and 8% in the poor and unsatisfactory categories respectively. Mean rated values of the two image sets (before and after wiping) were not statistically different, but ratings slightly improved after cleaning the plates.

Conclusions: Plates with Category 5 artifacts should be removed from clinical use. Bare PSPs can be easily damaged. The longevity of the plates can be increased by (a) making the protective clear coating more durable by the manufacturer (b) the clinicians should handle the plates gently. Wiping all plates to remove surface contamination may not always be necessary or desired.