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This article aims at the development of the fast inverse Monte Carlo (MC) simulation for the reconstruction of
optical properties (absorption coefficient μs and scattering coefficient μs) of cylindrical tissue, such as a cervix,
from the measurement of near infrared diffuse light on frequency domain. Frequency domain information (amplitude
and phase) is extracted from the time domain MC with a modified method. To shorten the computation time in
reconstruction of optical properties, efficient and fast forward MC has to be achieved. To do this, firstly, databases of
the frequency-domain information under a range of μa and μs were pre-built by combining MC simulation with
Lambert-Beer's law. Then, a double polynomial model was adopted to quickly obtain the frequency-domain
information in any optical properties. Based on the fast forward MC, the optical properties can be quickly obtained in a
nonlinear optimization scheme. Reconstruction resulting from simulated data showed that the developed inverse MC
method has the advantages in both the reconstruction accuracy and computation time. The relative errors in
reconstruction of the μs and μs are less than ±6% and ±12% respectively, while another coefficient (μs or μs) is in
a fixed value. When both μs and μs are unknown, the relative errors in reconstruction of the reduced scattering
coefficient and absorption coefficient are mainly less than ±10% in range of 45< μs <80 cm-1 and 0.25< a μ <0.55 cm-1.
With the rapid reconstruction strategy developed in this article the computation time for reconstructing one set of the
optical properties is less than 0.5 second. Endoscopic measurement on two tubular solid phantoms were also carried out
to evaluate the system and the inversion scheme. The results demonstrated that less than 20% relative error can be
achieved.
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