36. Software suite for 3D dose analysis: demonstrating the importance of image registration in RT dose verification

There is now an internationally recognised need to improve 3D verification of highly conformal radiotherapy treatments. This is because of the very high dose gradients used in modern treatment techniques, which can result in a small error in the spatial dose distribution leading to a serious complication. In order to gain the full benefits of using 3D dosimetric technologies, it is vital to use 3D evaluation methods and algorithms. We present in this paper a software solution that provides a comprehensive 3D dose evaluation and analysis. Evaluated dose distribution is spatially aligned with the reference distribution prior to verification analysis. The Bspline registration algorithm has demonstrated a higher reliability in dose image registration than the demon algorithm. The software is applied to gel dosimetry, which is based on magnetic resonance imaging (MRI) as a read-out method. The software can also be used to compare any two dose distributions, such as two distributions planned using different methods of treatment planning systems, or different dose calculation algorithms.