Biologically-optimised IMRT based on molecular imaging of tumour hypoxia-the impact of the tracer used

摘要

One of the most challenging tasks of current radiation therapy is the individualisation of the treatment plans through biological optimisation and adaptation to functional aspects. This study aims to explore the robustness of a newly proposed method of treatment planning optimisation based on patient-specific radiation sensitivity determined by tumour hypoxia. Theoretical three-dimensional tumours with heterogeneous oxygenations were used to investigate the efficiency of various approaches for calculating the optimal dose distribution and the effects of reoxygenation during the treatment duration. The impact of the spatial averaging implied by the imaging method in combination with the binding properties of the tracer used has also been investigated. It has been shown that a newly proposed method for dose prescription based on functional imaging of hypoxia could lead to improved local control for several tracers that could be practically used. The approach for dose prescription appears to have a significant impact for tumours with dynamic hypoxia. Furthermore, the average implied by the imaging method could reduce the effectiveness of the method, but it still has the potential to provide significantly better results than methods employing highly heterogeneous dose distributions. The results showed that planning and optimisation of treatments based on hypoxia information from PET images is feasible and could provide the tool for individualising the planning on biological and molecular bases.