title: Numerical simulations on conformable laser-induced interstitial thermotherapy through combined use of multi-beam heating and biodegradable nanoparticles.
abstract: Clinically, precisely heating and thus completely ablating diseased tumor tissue through laser beam is still facing many technical challenges. In this study, numerical simulation of a conformal heating modality based on multi-beam laser along with biodegradable magnesium nanoparticles (Mg-NPs) was put forward to treat liver tumor with large size or irregular shape. Further, a Gaussian-like distribution was proposed to investigate the influence of Mg-NP deposition on the nanoenhanced laser-induced interstitial thermotherapy (LITT). A temperature feedback system was adopted to control the temperature range to avoid overheating. To preliminarily validate the heating enhancement induced by the applied multi-beam laser and Mg-NPs, a conceptual experiment was performed. Both theoretical simulation and experimental measurements demonstrated that multi-beam laser with Mg-NPs could improve efficiency in the conformal heating of tumors with irregular shape or large size. In addition, the distribution and content of Mg-NPs produced significant impact on thermotherapy: (1) The adjustable parameter σ in the Gaussian-like distribution could reflect various practical situations and diffusivities of Mg-NPs; (2) under the premise of the same concentration of Mg-NPs and short time to heat a small-sized target, the whole liver tumor containing Mg-NPs could not improve the efficiency as the nanoparticles limited the photons to be absorbed only around the fibers, while liver tumor partially containing Mg-NPs could improve the thermotherapy efficiency up to 20 %; and (3) the addition of Mg-NPs was rather beneficial for realizing a conformal heating as the residual thermal energy was much less than that without Mg-NPs. This study suggests a feasible and promising modality for planning a high-performance LITT in future clinics.
authors.affiliation: Department of Biomedical Engineering, School of Medicine, Tsinghua University, 100084, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Chao
authors.initials: C
authors.lastname: Jin
authors.forename: Zhi-Zhu
authors.initials: ZZ
authors.lastname: He
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
mesh_terms: D003198:Computer Simulation; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D008113:Liver Neoplasms / Q000628:therapy*; D008954:Models, Biological; D053758:Nanoparticles / Q000627:therapeutic use*