SU-E-CAMPUS-T-05: Preliminary Results On a 2D Dosimetry System Based On the Optically Stimulated Luminescence of Al2O3

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Abstract

Purpose:

To develop a precise 2D dose mapping technique based on the optically stimulated luminescence (OSL) from Al2O3 films for medical applications.

Methods:

A 2D laser scanning reader was developed using fast F+-center (lifetime of <7 ns) and slow F-center (lifetime of 35 ms) OSL emission from newly developed Al2O3 films (Landauer Inc.). An algorithm was developed to correct images for both material and system properties. Since greater contribution of the F??-center emission in the recorded signal increases the readout efficiency and robustness of image corrections, Al2O3:C,Mg film samples are being investigated in addition to Al2O3:C samples. Preliminary investigations include exposure of the films to a 6 MV photon beam at 10 cm depth in solid water phantom with an SSD of 100 cm, using a 10 cm × 10 cm flat field or a 4 cm × 4 cm field with a 60° wedge filter. Kodak EDR2 radiographic film and EBT2 Gafchromic film were also exposed for comparison.

Results:

The results indicate that the algorithm is able to correct images and calculate 2D dose. For the wedge field irradiation, the calculated dose at the center of the field was 0.9 Gy for Al2O3:C and 0.87 Gy for Al2O3:C,Mg, whereas, the delivered dose was 0.95 Gy. A good qualitative agreement of the dose profiles was obtained between the OSL films and EDR2 and EBT2 films. Laboratory tests using a beta source suggest that a large dynamic range (10−2−102 Gy) can be achieved using this technique.

Conclusion:

A 2D dosimetry system and an in-house image correction algorithm were developed for 2D film dosimetry in medical applications. The system is in the preliminary stage of development, but the data demonstrates the feasibility of this approach. This work was supported by Landauer, Inc.

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