Optimization of a fast optical CT scanner for nPAG gel dosimetry

Jan Vandecasteele*, Yves De Deene

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Citations (Scopus)


A fast laser scanning optical CT scanner was constructed and optimized at the Ghent university. The first images acquired were contaminated with several imaging artifacts. The origins of the artifacts were investigated. Performance characteristics of different components were measured such as the laser spot size, light attenuation by the lenses and the dynamic range of the photo-detector. The need for a differential measurement using a second photo-detector was investigated. Post processing strategies to compensate for hardware related errors were developed. Drift of the laser and of the detector was negligible. Incorrectly refractive index matching was dealt with by developing an automated matching process. When scratches on the water bath and phantom container are present, these pose a post processing challenge to eliminate the resulting artifacts from the reconstructed images Secondary laser spots due to multiple reflections need to be further investigated. The time delay in the control of the galvanometer and detector was dealt with using black strips that serve as markers of the projection position. Still some residual ringing artifacts are present. Several small volumetric test phantoms were constructed to obtain an overall picture of the accuracy.

Original languageEnglish
Article number012024
Pages (from-to)1-7
Number of pages7
JournalJournal of Physics: Conference Series
Publication statusPublished - 2009
Externally publishedYes

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