Radiobiological investigations at tumor cell lines by exploiting chrono-biological aspects of chronological dose distributions

TL;DR

This study explores how circadian, circa-semiseptan, and circa-septan biological rhythms influence tumor cell metabolism and radiation sensitivity, aiming to optimize radiotherapy timing based on these biological cycles.

Contribution

It introduces a novel approach to optimize tumor irradiation timing by incorporating multiple biological rhythms into radiotherapy planning.

Findings

Identification of key biological cycles affecting tumor metabolism.

Optimal radiation timing aligns with ATP maxima across cycles.

Exploiting biological rhythms can enhance radiotherapy effectiveness.

Abstract

Using 31P-NMR spectroscopy the chronological behavior of the ATP-metabolism of the tumor spheroids C3H-MA, 9L-Gliome and the mono-layer L1210 has been analyzed via decrease of the {\beta}-peak. All three cell lines show characteristic periods, and a homeostatic control cannot be recognized. Essential components of these periods are circadian (i.e. one day), circa-semiseptan (i.e. 3.5 days) and circa-septan (i.e. one week). The determination of the survival fractions provides an optimum exploitation of radiation damages, when the ATP-concentration assumes a maximum value. This optimum is reached, when all three cycles exhibit the ATP maximum, which is only possible by accounting for the circa-septan rhythm. The goal of this study is to elaborate an optimal fractionation scheme with regard to the irradiation of tumors.