Purpose: The extensive use of multislice computed tomography (MSCT) and the associated increase in patient dose calls for an accurate dose evaluation technique. Optically stimulated luminescence (OSL) dosimetry provides a potential solution to the arising concerns over patient dose. This study was intended to evaluate the feasibility and accuracy of OSL dosimeter systems in the diagnostic CT x-ray beam energy range. Methods: MSCT dose profiles were measured by irradiating OSL strips placed inside the extended PMMA head and body phantoms at different scan conditions by varying kVp settings (100, 120, and 140 kVp) and collimated beam widths (5, 10, 20, and 40 mm). All scans in this study were performed using a GE Lightspeed VCT scanner in axial mode. The exposed strips were then read out using a custom-made OSL strip reader and corrected with field-specific conversion factors. Based on the corrected OSL dose profile, the CTDI 450 -OSL and CTDI 100 -OSL were evaluated. CTDI 100 -IC was also obtained using a 100 mm long pencil ionization chamber for accuracy verification. CTDI 100 -efficiency can be further evaluated by calculating the ratio of CTDI 100 -OSL and CTDI 450 -OSL , which was compared to results from previous studies as well. Results: The OSL detectors were found to have good sensitivity and dose response over a wide range of diagnostic CT x-ray beam energy viz. the primary beam and the scatter tail section of the dose profile. The differences between CTDI 100 values obtained using the OSL strips and those obtained with 100 mm long pencil ionization chamber were < ± 5 % for all scan conditions, indicating good accuracy of the OSL system. It was also found that the CTDI 100 -efficiency did not significantly change as the beam width increased and tube voltage changed. The average CTDI 100 -efficiency at the center of the head and body phantoms were 72.6% and 56.2%, respectively. The corresponding values for the periphery of the head and body phantoms were 85.0% and 81.7%. These results agreed very well with previous results from the literature using other detection techniques or Monte Carlo simulations. Conclusions: The LED-based OSL system can be an accurate alternative device for CT dose evaluations. CTDI 100 measurement with the use of a 100 mm pencil ionization chamber substantially underestimates the CTDI ∞ value even with 5 mm collimated beam width. The established complete set of CTDI 100 -efficiency correction factors for various scan parameters allows for accurately estimating CTDI ∞ with the current use of pencil chamber and dose phantoms. Combined with the simple calibration, it gives this work great potential to be used not only in routine clinical quality assurance checks but also as a promising tool for patient organ dose assessment.