Background: Laser therapies can provide a minimally invasive treatment alternative to surgical resection for small poorly defined metastases or tumors embedded within vital regions. However, implementation of laser therapies is limited due to nonspecific heating of target tissue which often leads to healthy tissue injury and extended treatment durations. These therapies can be further compromised due to heat shock protein (HSP) induction in regions of the tumor where non-lethal temperature elevation occurs, thereby imparting enhanced tumor cell viability and resistance to subsequent chemotherapy and radiation treatments. The future potential of laser therapies for cancer treatment could be greatly enhanced by introducing sensitizing agents called multi-walled nanotubes (MWNT) into the target tissue prior to laser irradiation. Integrating MWNT into laser treatment can permit increased heating selectivity, lower required thermal doses for more precise thermal energy delivery to the tumor region, and permit greater temperature elevations within the tumor thereby increasing tumor injury and reducing HSP expression induction. Development of effective combinatorial therapies involving MWNT and laser irradiation, require determination of optimal MWNT characteristics and laser parameters for maximum tumor destruction.

Methods: We have developed a treatment planning computational model for predicting the tissue response to laser irradiation with MWNT inclusion. The heat generated due to varying MWNT characteristics are predicted based on measured optical properties of gel phantoms with MWNT inclusion and Monte Carlo Models. Novel tissue response models for tumor recurrence based on measured thermally induced HSP expression and tumor injury determined from Arrhenius damage models are utilized. Magnetic resonance imaging data is integrated into the model to provide both patient specific data and validation of temperature prediction.

Results: This treatment planning tool permits exploration of how varying MWNT properties (MWNT concentration and distribution of tubes within the tissue and legth of tubes) and laser parameters (wavelength, power, pulse duration, optical fiber orientation, and fiber number) affect the tissue response to MWNT-mediated laser therapy.

Conclusion: To our knowledge, this is the first computational treatment planning model for prediction of the tissue response to MWNT-mediated laser therapy.