Regensburg 2019 – wissenschaftliches Programm

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ST: Fachverband Strahlen- und Medizinphysik

ST 6: Radiation Therapy

ST 6.6: Vortrag

Mittwoch, 3. April 2019, 16:30–16:45, H48

Modelling the physical mechanism for thermal enhancement of radiation therapy — •Adriana De Mendoza, Jens Karschau, Sona Michlikova, and Damian McLeod — OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital C. G. Carus, TU Dresden, HZDR, Dresden, Germany.

Radiation therapy (RT) is one of the pillars in the fight against cancer. It is a potent killer of cancer cells, but at the cost of collateral damage to healthy tissue. Previous studies found that combination of RT with local hyperthermia (HT) can not only reduce whole tissue toxicity but also improve control of tumor growth. We here propose a consistent model to further understand the thermal enhancement of RT on the basis of theoretical as well as mechanistic explanations. We propose that the main driver of the thermal enhancement ratio is sub-lethal cellular damage caused by mild HT. Using a three-stage cell model [(A)<->(*)->(D): alive, activated, dead] we explain that cells are prepared to die through a reversible transition, and then die in a non-reversible process if the right amount of additional energy is applied. Including the appropriate thermodynamic considerations, we show that TER is proportional to the energy deposited in the process (A)<->(*), finding the same exponential dependence on temperature that was found empirically by other authors. Our model reproduces to good precision different experimental data sets from in-vitro and in-vivo studies for simultaneous application of moderate HT and RT.