In biomedical optics, the mean fluence rate of photons, assessed in a sub-volume of a propagating medium, is classically obtained in Monte Carlo simulations by taking into account the power deposited by the absorbed photons in the sub-volume. In the present contribution, we propose and analytically demonstrate an alternative method based on the assessment of the mean pathlength traveled by all the photons inside the sub-volume. Few practical examples of its applications are given. This method has the advantage of improving, in many cases, the statistics and the convergence of the Monte Carlo simulations. Further, it also works when the absorption coefficient is nil and for a non-constant spatial distribution of the absorption coefficient inside the sub-volume. The proposed approach is a re-visitation of a well-known method applied in radiation and nuclear physics in the context of radiative transfer, where it can be derived in a more natural manner.

Fluence rate directly derived from photon pathlengths: a tool for Monte Carlo simulations in biomedical optics / Sassaroli A.; Tommasi F.; Cavalieri S.; Martelli F.. - In: BIOMEDICAL OPTICS EXPRESS. - ISSN 2156-7085. - ELETTRONICO. - 14:(2023), pp. 477339.148-477339.162. [10.1364/BOE.477339]

Fluence rate directly derived from photon pathlengths: a tool for Monte Carlo simulations in biomedical optics

Tommasi F.;Cavalieri S.;Martelli F.
2023

Abstract

In biomedical optics, the mean fluence rate of photons, assessed in a sub-volume of a propagating medium, is classically obtained in Monte Carlo simulations by taking into account the power deposited by the absorbed photons in the sub-volume. In the present contribution, we propose and analytically demonstrate an alternative method based on the assessment of the mean pathlength traveled by all the photons inside the sub-volume. Few practical examples of its applications are given. This method has the advantage of improving, in many cases, the statistics and the convergence of the Monte Carlo simulations. Further, it also works when the absorption coefficient is nil and for a non-constant spatial distribution of the absorption coefficient inside the sub-volume. The proposed approach is a re-visitation of a well-known method applied in radiation and nuclear physics in the context of radiative transfer, where it can be derived in a more natural manner.
2023
14
148
162
Goal 3: Good health and well-being
Sassaroli A.; Tommasi F.; Cavalieri S.; Martelli F.
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1301481
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