Abstract A16: Using 3D tumor simulations to determine optimal therapeutic conditions for the cold atmospheric plasma device
Authors: Murphy William , Brieda Lubos , Schweigert Irina , Keidar Michael 
Published: March 2017

Abstract
It has been shown that cold atmospheric plasma (CAP) can selectively treat cancer cells while leaving healthy cells relatively unharmed through both in vitro and in vivo experiments. This plasma contains reactive oxygen and nitrogen species at room temperatures, which drives the selective ability of the plasma jet to cancer cells. The translation of this therapeutic into surgical application is being limited by knowledge of its mechanism and poorly-defined standards for optimal treatments. Previous research seeks to answer these questions, including studying the tunable effect of the jet and how external parameters affect treatment outcome.
Time-dependent ROS generation rates near the tissue surface provided by plasma jet are studies in 2D fluid model simulation. A specific set of balance equations for chemical species for two types of mixtures He/air and Ar/air are developed. We study additional oxygen portions effect on the ROS production. These simulations will be used to provide boundary conditions for the CAP-tumor interactions.
Two types of parameters have been defined in this study that have an affect on the outcome of CAP tumor therapy [1]: (1) CAP-specific parameters and (2) tumor-specific parameters. CAP-specific parameters include the number and type of species produced, the duration of treatment and size of the treatment area. Tumor-specific parameters include the cellular response to plasma, the growth-rate of the tumor and overall tumor geometry. A 3D tumor simulation was created that can model the effect of the CAP therapy on a hemispherical tumor, using agent-based simulation techniques. Both CAP-specific and tumor-specific parameters where varied in treatment simulations to define a set of standards for optima treatment outcomes.
When varying CAP-specific parameters, it was determined that the concentration of plasma species used and the percentage of the tumor surface area treated has the greatest affect on tumor treatment outcome. Likewise, the location/angle of treatment seemed to have an affect on treatment outcome with respect to the geometry of the tumor. For tumor-specific parameters, the growth rate of the tumor seemed to not have an affect on the treatment outcome, while cellular chemical reactions that increased internal ROS of the cell decreased the treatment time. Likewise, cellular chemical reactions that decreased ROS of the cell increased the treatment time. Using computational simulations, a set of standards for optimal treatment conditions that describe both the tumor-specific and CAP-specific parameters has been elucidated.
This work was partially supported by National Science Foundation, grant 1465061.
References
[1] W. Murphy, C. Carroll, M. Keidar, Simulation of the effect of plasma species on tumor growth and apoptosis”, J. Phys. D: Applied Physics (Fast Communication), vol. 47 (2014) 472001.
Citation Format: William Murphy, Lubos Brieda, Irina Schweigert, Michael Keidar. Using 3D tumor simulations to determine optimal therapeutic conditions for the cold atmospheric plasma device. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A16.