Numerical modeling of photon migration in human neck based on the   radiative transport equation
  Biomedical optical imaging has a possibility of a comprehensive diagnosis of thyroid cancer in conjunction with ultrasound imaging. For improvement of the optical imaging, this study develops a higher order scheme for solving the time-dependent radiative transport equation (RTE) by use of the finite-difference and discrete-ordinate methods. The accuracy and efficiency of the developed scheme are examined by comparison with the analytical solutions of the RTE in homogeneous media. Then, the developed scheme is applied to describing photon migration in the human neck model. The numerical simulations show complex behaviors of photon migration in the human neck model due to multiple diffusive reflection near the trachea. 
Hiroyuki Fujii, Shinpei Okawa, Ken Nadamoto, Eiji Okada, Yukio Yamada,   Yoko Hoshi, and Masao Watanabe
physics.med-ph