Biological Treatment Planning: Calculation of Normal Tissue Complication Probabilities Based on Dose-Volume Analysis of Three-Dimensional Treatment Plans

Future applications of biological treatment planning in routine clinical work may include, on the one hand, the design and comparison of fractionation schemes with planned and unplanned treatment pauses and, on the other, alternate schemes with hyperfractionated or accelerated treatment for improving therapeutic results. This kind of planning may utilize radiobiological models such as linear quadratic formalism [1, 2], which can be extended to account for individual effects of cell repair and kinetics such as incomplete repair and repopulation [3, 4]. The second issue in biological treatment planning is the consideration of volume effects on normal tissues and tumors. For this purpose several methods have been developed which calculate normal tissue complication probabilities (NTCP) and tumor control probabilities for inhomogeneously irradiated volumes of tissue.