title: Investigation of thermal distribution for pulsed laser radiation in cancer treatment with nanoparticle-mediated hyperthermia.
abstract: In this paper, we have simulated the efficacy of gold/gold sulfide (GGS) nanoshells in NIR laser hyperthermia to achieve effective targeting for tumor photothermal therapy. The problem statement takes into account the heat transfer with the blood perfusion through capillaries, and pulsed laser irradiation during the hyperthermia. Although previous researchers have used short laser pulses (nanosecond and less), in order to prevent heat leakage to the neighbor tissues, we have examined the effect of millisecond pulses, as the extent of the target volume to which hyperthermia is induced is usually larger and also the lasers with this specification are more available. A tumor with surrounding tissue was simulated in COMSOL software (a finite element analysis, solver and simulation software) and also in a phantom made of agarose and intralipid. The tumor was irradiated by 10, 20 and 30 laser pulses with durations of 15, 50 and 200ms and fluences of 20, 40 and 60J/cm(2). Experimental tests performed on a phantom prove the ability of the applied numerical model to capture the temperature distribution in the target tissue. We have shown that our simulation permits prediction of treatment outcome from computation of thermal distribution within the tumor during laser hyperthermia using GGS nanoshells and millisecond pulsed laser irradiation. The advantage of this simulation is its simplicity as well as its accuracy. Although, to develop the model completely for a given organ and application, all the parameters should be estimated based on a real vasculature of the organ, physiological conditions, and expected variation in those physiological conditions for that application in the organ.
authors.affiliation: Medical Physics Research Center, Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Ameneh
authors.initials: A
authors.lastname: Sazgarnia
authors.affiliation: Department of Electrical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran. Electronic address: n.naghavi@um.ac.ir.
authors.forename: Nadia
authors.initials: N
authors.lastname: Naghavi
authors.affiliation: Department of Electrical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran.
authors.forename: Hoda
authors.initials: H
authors.lastname: Mehdizadeh
authors.affiliation: Medical Physics Research Center, Bu-Ali Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Shahamat
mesh_terms: D003198:Computer Simulation; D004867:Equipment Design; D020342:Finite Element Analysis; D006046:Gold / Q000528:radiation effects / Q000627:therapeutic use; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced / Q000009:adverse effects / Q000295:instrumentation*; D007259:Infrared Rays; D053685:Laser Therapy / Q000379:methods*; D008954:Models, Biological; D057145:Nanoshells / Q000627:therapeutic use*; D009369:Neoplasms / Q000601:surgery*
chemical_list: D006046:Gold
keywords: Cancer; Gold/gold sulfide nanoshells; Hyperthermia; Laser; Numerical simulation