Room: Exhibit Hall | Forum 4
Purpose: Measurements of dose distribution are important for high energy X-ray beam from linear accelerators (LINAC) for quality assessment (QA) of the system. Although optical imaging of water during irradiations of X-ray beam from a LINAC is a promising method, dose profiles showed underestimation in deeper part of the water probably because of the angular dependency of the produced light in water.
Methods: We added vitamin B2 to water phantom and optical images of the vitamin B2 water were measured with a high-sensitivity cooled charge coupled device (CCD) camera during X-ray beam irradiations and compared the results with those of water. Then we set the depth and lateral profiles in these optical images and compared the distributions.
Results: Without addition of vitamin B2 to water, the depth profiles showed ~20 % smaller value than those calculated by the planning system at 10cm depth for 6 MV X-ray. With the addition of vitamin B2 to water, we could obtain almost the same depth profiles as those calculated by the planning system for all the depths. The lateral profiles were almost same as those of water.
Conclusion: The addition of vitamin B2 to water significantly improved the accuracy of the dose profiles of the optical images of water. We conclude that, with the addition of vitamin B2 to water, optical imaging can be used for dose estimation of X-ray from LINAC.