A new finite element approach for near real‐time simulation of light propagation in locally advanced head and neck tumors
نویسندگان
چکیده
BACKGROUND AND OBJECTIVES Several clinical studies suggest that interstitial photodynamic therapy (I-PDT) may benefit patients with locally advanced head and neck cancer (LAHNC). For I-PDT, the therapeutic light is delivered through optical fibers inserted into the target tumor. The complex anatomy of the head and neck requires careful planning of fiber insertions. Often the fibers' location and tumor optical properties may vary from the original plan therefore pretreatment planning needs near real-time updating to account for any changes. The purpose of this work was to develop a finite element analysis (FEA) approach for near real-time simulation of light propagation in LAHNC. METHODS Our previously developed FEA for modeling light propagation in skin tissue was modified to simulate light propagation from interstitial optical fibers. The modified model was validated by comparing the calculations with measurements in a phantom mimicking tumor optical properties. We investigated the impact of mesh element size and growth rate on the computation time, and defined optimal settings for the FEA. We demonstrated how the optimized FEA can be used for simulating light propagation in two cases of LAHNC amenable to I-PDT, as proof-of-concept. RESULTS The modified FEA was in agreement with the measurements (P = 0.0271). The optimal maximum mesh size and growth rate were 0.005-0.02 m and 2-2.5 m/m, respectively. Using these settings the computation time for simulating light propagation in LAHNC was reduced from 25.9 to 3.7 minutes in one case, and 10.1 to 4 minutes in another case. There were minor differences (1.62%, 1.13%) between the radiant exposures calculated with either mesh in both cases. CONCLUSIONS Our FEA approach can be used to model light propagation from diffused optical fibers in complex heterogeneous geometries representing LAHNC. There is a range of maximum element size (MES) and maximum element growth rate (MEGR) that can be used to minimize the computation time of the FEA to 4 minutes.
منابع مشابه
Modeling Time Resolved Light Propagation Inside a Realistic Human Head Model
Background: Near infrared spectroscopy imaging is one of the new techniques used for investigating structural and functionality of different body tissues. This is done by injecting light into the medium and measuring the photon intensity at the surface of the tissue.Method: In this paper the different medical applications, various imaging and simulation techniques of NIRS imaging is described. ...
متن کاملQuantitative Comparison of Analytical solution and Finite Element Method for investigation of Near-Infrared Light Propagation in Brain Tissue Model
Introduction: Functional Near-Infrared Spectroscopy (fNIRS) is an imaging method in which light source and detector are installed on the head; consequently, re-emission of light from human skin contains information about cerebral hemodynamic alteration. The spatial probability distribution profile of photons penetrating tissue at a source spot, scattering into the tissue, and being released at ...
متن کاملA Review on the Efficacy of Chemotherapy in Locally Advanced Head and Neck Cancers
Background and Aims: Chemotherapy is utilized as a part of combined-modality programs to achieve organ preservation and improve survival in patients with locally advanced head and neck cancer. Combinedmodality protocols can be used in three forms: a) neoadjuvant induction chemotherapy before definitive surgery or radiotherapy; b) concomitant chemoradiotherapy; and c) sequential therapy consisti...
متن کاملFinite element simulation of pyroplastic deformation, anisotropic shrinkage and heterogeneous densification for ceramic materials during liquid phase sintering process
Pyroplastic deformation is a distortion of the ceramic shape during the sintering process. It occurs because the flow of the vitreous phase at high temperature and the applied stress due to the weight of the product during sintering process. The aim of this paper deals with describing a numerical-experimental method to evaluate the pyroplastic deformation, to predict the anisotropic shrinkage a...
متن کاملFinite-Difference Time-Domain Simulation of Light Propagation in 2D Periodic and Quasi-Periodic Photonic Structures
Ultra-short pulse is a promising technology for achieving ultra-high data rate transmission which is required to follow the increased demand of data transport over an optical communication system. Therefore, the propagation of such type of pulses and the effects that it may suffer during its transmission through an optical waveguide has received a great deal of attention in the recent years. We...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره 47 شماره
صفحات -
تاریخ انتشار 2015