Computed Tomography Measurements Using Optically Stimulated Luminescence of KBr:Eu In Real-Time.

Increasing complexity in modern scanning geometries invalidates the concept of computed tomography dose index (CTDI) for CT dosimetry. A real-time dosimetry system using optically stimulated luminescence (OSL) of KBr:Eu is evaluated in comparison with a pencil ionization chamber for CT dosimetry in this study. CT scans were measured over a relevant range of energies and tube currents using a GE LightSpeed Ultra scanner. Complete OSL signals were obtained before, during, and after the CT scans at a rate of 10Hz. Performance was determined in part by normalizing both the initial OSL intensity and the background-subtracted integral OSL to exposure reported by an ionization chamber. OSL response normalized to exposure shows good correlation with coefficients of variation of $\sim ${\%}5 or less. Results show that this OSL dosimetry system possesses great potential for faster, higher-resolution CT characterization and may prove a valuable alternative to CTDI.