Cancer cell survival model after photodynamic therapy

Abstract

Photodynamic therapy (PDT) is known as a routine treatment method in which cell survival index like viability plotted versus 1O2 concentration or light fluence in the form of a curve. In this paper, a mathematical model was proposed with ability of generating a mirrored-sigmoid curve which seems to be fitted to any experimental data relating to cell viability, survival probability or any cellular index representing living conditions through adjusting three parameters. It was validated by showing an excellent curve fitting relatively with data obtained from cancerous lung cells under ALA-PDT process in vitro. It was tried to define the relations between model’s parameters and biological/clinical factors with the curve regions of plateau (at low doses; non- sensitive part), steep (high-sensitive part), and steady state (at high doses; low-sensitive part). It seems this model could be excellently fitted to any data presenting the cell-living index versus the killer agent in «any cancer therapy technique (e.g. radiotherapy)». Although this claim showed to be correct for PDT, different relevant data of other researchers should also be used for this model and other usual models too, in order to compare their fitness rates.

Keywords

• cell survival curve
• mathematical modeling
• photodynamic therapy