Fundamental experiments and numerical investigation of cryo-freezing incorporating vascular network with enhanced nano-freezing

Abstract

Structural blood networks and blood perfusion rate of a tumor impact the manner in which cryosurgery is carried. In locations where complex vascular systems exist, the freezing temperature of the cryoprobes must account for these additional heat sources while maximizing the eradication of cancer cells. In this study, a computational cryo-freezing model that incorporates a simplified mathematical description of the vascular morphology has been constructed. Complex vascular network with varied blood flows were simplified and modeled as tree-like branched fractal network. The present work evolved a simplified and time-saving methodology to accurately simulate complex blood vessel network in order to reduce simulation tediousness and computational cost. A thermal freezing algorithm has been employed to generate transient temperature profiles, to visualize isotherms in the anatomical region of interest and to provide essential information the ice-front propagation. Extensive experimental validation of the proposed model has been performed with good agreement of up to 4.3%. Effects of combining cryosurgery with advanced nanotechnology to better regulate ice-ball development within a biological tissue were quantitatively investigated. Depending on the thermal properties of different nanoparticles, they could either enhance heat conduction or retard freezing to minimize unintended cryoinjury to the neighboring tissue. Hence, key results have confirmed that while certain nanoparticles act as therapeutic freezing agents that promote cryoablation, others are capable of protecting surrounding healthy tissue. © 2013 Elsevier Masson SAS. All rights reserved.