Unsettled Issues in the Radiobiology of Emergent Technology: Hypofractionation and PET-Guided Treatment Planning
M Joiner1*, R Jeraj2*, S Bentzen3*, (1) Wayne State Univ, Detroit, MI, (2) University of Wisconsin, Madison, WI, (3) University of Wisconsin, Madison, WIMO-A-BRCD-1 Monday 8:00:00 AM - 9:55:00 AM Room: Ballroom CD
New technologies and innovative treatment techniques call into question long-standing radiobiological principles in RT. Reported apoptosis effects above 10 Gy/fraction challenge standard views of tumor cell kill as the only important path to tumor control. There are also reports of an immune-system response to large-dose per fraction. Repair-kinetics can also become important when comparing treatments given in less than 10 minutes to treatments given over 30 minutes or more. Modeling studies challenge the importance of hypoxia (and use of the linear quadratic model) in hypofractionation treatments. Critical questions regarding the use of FDG-PET guided boosts include the expected dose needed to achieve local control for FDG-PET positive tumors, and the relationship between FDG-PET images and underlying cellular parameters. This symposium will review our current scientific understanding of these important, unsettled issues.
1. Review non-classical radiobiology relevant to high-doses per fraction
2. Review dose-rate effects as they apply to SBRT/hypofx treatments
3. Review radiobiology of FDG-PET guided therapy