Welcome to the professional web page of Dr. Arthur Gautheron.

AG is an engineer who graduated from the Institut d’Optique Graduate School.
In 2019, he also received two other degrees, one university degree from the Institut de Formation Supérieure en Biomédical (IFSBM, Paris Saclay Université) and a master degree in automatic & signal and images processing from Université Paris-Saclay.

AG started in 2019 a thesis in engineering for health (biomedical optics, optical modeling and signal processing) under the supervision of Bruno Montcel from CREATIS (Université Claude Bernard, Lyon) and Mathieu Hébert from LHC (Université Jean Monnet, Saint-Etienne). His thesis was funded by the Labex PRIMES and is briefly summarized here. He successfully defended his Ph.D thesis on the 8th of December 2022.

In 2023, AG was appointed as a 18-month post-doctoral fellow in the BIOSPEC - Research Project funded by the Manutech Sleight Graduate School. He is thus member of the Image team (LHC, Saint-Etienne) and the MAGICS team (CREATIS, Lyon).


  1. Short CV
  2. Research interests
  3. Publications
  4. Softwares
  5. Teaching
  6. Administrative functions

Short CV

Full CV pdf (fr)

Research interests

AGs expertise lies in the field of biomedical optics, which encompasses a wide range of theoretical and practical aspects: signal processing, optical modeling, experimental expertise. He is particularly interested in exploring the following research topics: fluorescence spectroscopy for intraoperative diagnosis, biomedical engineering at the bedside, radiative transfer for appearance prediction, inverse problems for optical properties extraction, fast and operating room compatible acquisition systems…

Keywords: Fluorescence spectroscopy, Signal Processing, spectral unminxing, Classification, Biomedical Engineering, intra-operative Optic Tools, Optical Modeling, Radiative Transfer, PpIX, Glioma, Focal Cortical Dysplasia, Actinic Keratosis

Fluorescence spectral unmixing

The main contribution of AG thesis to spectral unmixing theory is a method to estimate the contribution of biomarkers related to PpIX fluorescence using multiple excitation wavelengths. Indeed, current methods suffer from crosstalk when estimating biomarkers related to PpIX fluorescence. These crosstalks can be due to the omission or the wrong spectral shape of one or more endogenous fluorophores present in the measured signal. They occur when the spectrum of the omitted endogenous fluorophores is spectrally close to the PpIX emission spectral band and leads to an overestimation of PpIX and thus to a classification as “tumor” of the healthy tissue. The proposed method is free from preconceived ideas about the endogenous biomarkers present in the measured signal and their respective spectral shapes. For this purpose, several fluorescence excitation wavelengths are required to transfer the a priori in the fluorescence quantum yield of the biomarkers related to the PpIX fluorescence and to estimate the signal related to the endogenous biomarkers, called baseline.

AG ’s thesis provides a complete characterization of the different steps were performed for the validation of the method:

These results have led to several papers in international and national conferences as well as to the submission of a paper under review in the IEEE TBME journal.

Future Research Directions: extend the $2$-excitation wavelengths case, study the hot points issue…

Impact of internal reflectance on the estimation of optical properties of translucent media

Concerning optical modeling, AG ’s thesis focuses on improving the estimation of optical properties of biological tissues based on optical models approximating the radiative transfer equation. Let us recall that the quantification of biological biomarkers is based on more or less complex optical models, it seemed relevant to verify that some of the assumptions made in simple models are compatible with the case studied. One of them concerns the shape of the angular distribution of light. This assumption directly affects the value of a parameter called the internal reflectance, i.e. the reflectance of the air-tissue interface on the tissue side. Compared to the commonly used values of internal reflectance that depend only on the optical index of the medium, and that can induce an error on the prediction of reflectance and transmittance of about 10%, AG has shown that taking into account an accurate value of the internal reflectance of the tissue-air interface, depending on the thickness of the material and its optical properties, in simple optical models leads to a reduction of the error in the prediction of reflectance and transmittance to less than 1.0% for translucent media, such as biopsies.

Different steps were necessary to obtain these results:

These results led to a paper presented at the Electronic Imaging 2022 international conference and to the submission of an article to the Optics Express journal.

Future Research Directions: extend the D.O.M. to the resolution of RTE including fluorescence phenomenon (coupled RTE), study of internal reflectance parameter to extend the validity of diffusion approximation, compare inversion using D.O.M. with the one using Monte-Carlo, …

Experimental development

Last part of AG’s thesis concerns the development and characterization of an interventional fluorescence spectroscopy system aimed at both identifying the two forms of PpIX fluorescence and extracting the optical properties of the sample probed by diffuse reflectance spectroscopy (DRS).

This system is equipped with two lasers and a broadband white light source. The broadband white light source provides DRS measurements and the lasers sequentially excite the biological tissue with two distinct wavelengths and a spectrometer collects each emitted fluorescence spectrum. All excitation and detection is performed via a fiber optic probe.

Future Research Directions: realization of a clinical study on biological brain wastes, extension to measurements in Focal Cortical Dysplasia- and Actinic keratosis -resection

Characterization of the dose-response effect of nanoparticles by fluorescence spectroscopy for active dynamic X-PDT - European Project Scan’n’Treat

In AG’s thesis, he also took part to quantify the fluorescence emitted by the new nanoparticles manufactured within the framework of the project. This element is crucial to study the dose-response effect.

The objective of the dose-response characterization measurements is to successfully acquire the fluorescence spectrum for each type of nanoparticle and then to extract relevant criteria for each of the acquired spectra.

Since the fluorescence excitation signal is emitted by the SPCCT, it is necessary to have a timing signal indicating whether the X-rays are activated or not. After contacting Philips, it appears that attempts to obtain a direct signal from the gantry were met with obstacles. A simple alternative was to use a stand-alone scintillation detector, i.e. a basic scintillation detector connected to a photodiode. Philips provided us with a stand-alone detector measuring about 1x1x20 mm, the whole thing encapsulated in epoxy to protect it. Nevertheless, I developed an electronic circuit to acquire both the spectrum of the light background and the spectrum of the fluorescent signal. These two signals are a prerequisite to extract the fluorescence spectrum by subtracting the light background from the fluorescent signal. The resulting fluorescence spectrum matches perfectly with that of terbium III. To study the dose effect, I then post-processed the acquired data to characterize the evolution of the fluorescence signal as a function of the X-ray parameters (keV and mAs).

These results are the subject of a paper currently in progress.

Future Research Directions: application to small animals, quantification of singlet oxygen radicals using an absorbance measurement technique

Scientific Production




Radiative Transfer Equation 1D Solver

Radiative transfer equation solver in 1D geometry based on the discrete coordinates method.
Link to the code

Laser Spectral Fluorescence IHM

Software which interacts with an OceanInsight Spectrometer and an Arduino Board in order to control lasers Intensity, shutters and trigger of the acquisition process of Glioma Diffuse Fluorescence Spectroscopy.
Link to the code

LED Spectral Fluorescence IHM

Not up to date
Software which interacts with an OceanInsight Spectrometer and an National Instruments Board in order to control LEDs, shutter and triggers of the acquisition process of Glioma Diffuse Fluorescence Spectroscopy.
Link to the code


2022-2023 Vacancies planned during the post-doctoral fellow (45.5h)

A summary of the lessons being taught and to be taught during the 2022-2023 school year is presented in the table below. The content of these courses is detailed in the links.

Course title Structure Number of hours (Type) Level
Sensors and Instrumentation Polytech Lyon 18h (Theorical Sessions)
+ 12h (Practical Sessions)
undergraduation year (equivalent L3)
Biomedical Engineering Project Polytech Lyon 12h (Theorical Sessions) graduation year (M2)
Light Scattering for Material Appearance IOGS 1h (Lecture) + 3h (Theorical Session) graduation year (M2)

2019-2022 Complementary Teaching Activity (196h)

A summary of the courses taught during my thesis is presented in the table below. The content of these courses is detailed in the links. These teachings were realized between October 2019 and June 2022 in the framework of a complementary teaching activity (ACE) and correspond to an hourly volume of 196h over the 3 years.

Course title Structure Number of hours (Type) Level
Basics of Signal Processing ISTR Audioprothesist 50h (Practical Sessions) 1st year (equivalent L1)
Digital Electronics ISTR Audioprothesist 32h (Practical Sessions) 1st year (equivalent L1)
Sensors and Instrumentation Polytech Lyon 31.5h (Theorical Sessions)
+ 32h (Practical Sessions)
undergraduation year (equivalent L3)
Biomedical Engineering Project Polytech Lyon 16h (Theorical Sessions) graduation year (M2)
Transversal Lecture
Informatic Basics
Lyon 1 34.5h (Theorical Sessions) 1st year (L1)

Administrative functions