Pixel Bleeding Correction in Laser Scanning Luminescence Imaging Demonstrated Using Optically Stimulated Luminescence

This paper describes and investigates the performance of an algorithm to correct for “pixel bleeding” caused by slow luminescence centers in laser scanning imaging (e.g., X-ray imaging using photostimulable phosphors and 2D dosimetry using optically stimulated luminescence). The algorithm is based on a deconvolution procedure that takes into account the lifetime of the slow luminescence center and is further constrained by the detection of fast and slow luminescence centers and combining rows scanned in opposite directions. The algorithm was tested using simulated data and demonstrated experimentally by applying it to image reconstruction of two types of Al₂O₃ X-ray detector films (Al₂O₃:C and Al₂O₃:C,Mg), whose use in 2D dosimetry in conjunction with laser-scanning readout has so far been prevented by slow luminescence centers (F-centers, 35 ms lifetime). We show that the algorithm allows the readout of Al₂O₃ film detectors 300-500 times faster than generally allowed considering the lifetime of the main luminescence centers. By relaxing the stringent requirements on the detector´s luminescence lifetime, the algorithm opens the possibility of using new materials in 2D dosimetry as well as other laser scanning applications, such as X-ray imaging using storage phosphors and scanning confocal microscopy, although the effect of the noise introduced must be investigated for each specific application.