01 Juillet – Séminaire du département APY: Ratan K. SAHA

11 h

Le prochaine séminaire du département APY aura lieu le 1er juillet en salle de conférences du bâtiment A4. Nous avons l'honneur d'accueillir le professeur Ratan K. SAHA qui interviendra sur le thèse suivant:
"Modelling of photoacoustic signals from single cell to many cells"

Orateur : Ratan K. SAHA (Associate Professor at Indian Institute of Information Technology Allahabad, India)
Titre : Modelling of photoacoustic signals from single cell to many cells
Date : lundi 1er juillet 2019 à 11h
Lieu : salle de conférences du bât. A4

We have recently solved time independent photoacoustic (PA) wave equation using Green’s function method and accordingly, obtained the expression for a quantity known as differential PA cross-section (DPACS). The DPACS is defined as the amount of acoustic power received by a detector far away from the source per unit solid angle divided by the intensity of the light beam. We have calculated angular distribution of the DPACS for a series of spheroidal droplets, Chebyshev particles and normal and pathological red blood cells. Further, we have fitted DPACS curves using tri-axes ellipsoid form factor model to estimate morphological parameters of the PA sources. Attempt has also been made to fit frequency dependent DPACS data using the same form factor model to estimate size for those particles. In this presentation, we will present how accurate the method is. We previously solved the same PA wave equation employing the exact method for a cell assuming it as a homogeneous sphere and accordingly, evaluated the PA signal generated by it. The resultant PA signal from an ensemble of cells (tissue) was also computed by linearly superimposing the PA signals emitted by the individual cells. Such a modelling approach can serve as a useful tool to study various phenomena exhibited by blood. In this presentation, we will demonstrate the performance of the model to examine the effects of erythrocyte aggregation and oxygen saturation on PA signals. The potential of the PA technique detecting intraerythrocytic stages of malarial parasite and melanoma cells in blood stream has also been assessed exploiting this model. We will also briefly highlight our experimental and PA tomography image reconstruction works in this presentation.

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