Mesh-based human eye anatomy for Monte Carlo dose calculation

Abstract

Purpose: The purpose of this work is to explore the capability of the MCNP6 unstructured mesh geometry resources to create an eye and tumor anatomic model for ophthalmic brachytherapy dosimetry.

Methods: Abaqus/CAE software was utilized to construct three anatomic eye models using first order tetrahedral mesh elements: a model with a 2 cm in diameter deep tumor; a model with a 1.2 cm in diameter deep tumor; and a model with a 1.2 cm superficial tumor. 2 cm and 1.2 cm COMS applicators fully loaded with Amersham 6711125I seeds were coupled to the eye models for dose calculation using the MCNP6 code. The dose values in the structures of the eye were compared to those obtained using analytical models.

Results: Unstructured mesh model has small differences (maximum of 3.4%) in the mass values of the components of the eye comparing to those obtained in the analytical model. Excluding the optical nerve wall, all dose differences were beneath 4% for all structures. The overall dose in the eye agrees within 2% between different models.

Conclusions: The feasibility of using unstructured mesh based geometries to model fine structures of the eye has been verified in this study. It was possible to create adequately the anatomic model of the human eye with reproducible dose values compared to reference values.