Department of Mechanical and Aerospace Engineering

Overview

Analysis of short-pulse laser interaction with tissues is complicated because of the multiple scattering events suffered by the photons before emerging from the medium. A transient radiative transfer equation is solved using different techniques to obtain the scattered temporal reflected and transmitted optical signals. The modeling results are validated with the time-resolved signal measurements using a short-pulse laser and a streak camera. This technique is used to develop a new imaging tool for detection of tumors and cancer in tissues.

Kunal Mitra, Ph.D,
Tel: (321)674-7131, email: kmitra@fit.edu

Research Interests

Short-pulse lasers and x-rays for biomedical imaging and therapy; thermal radiation transport modeling and experiments through biological tissues and other participating media, Nanobiosensors for cellular interrogation; microscale heat transfer.

Current Research Projects

Study of Optical Tomography for Biomedical Imaging of Tissues

Using Short Pulse Laser Sources (Sponsored by Oak Ridge National Laboratory)

The objective of this research is to perform a comprehensive experimental and numerical study to analyze short pulse alser propagation through tissue phantoms containing inhomogeneities, and animal tissue samples.

Optical Tomography System Using Short Pulse Laser for Early Lung Cancer Detection (Sponsored by Florida Photonics Center of Excellence)

Early diagnosis, localization, and minimally invasive treatment of lung cancer are critical to its effective curative treatment. Due to the limitations of currently used conventional bronchoscopy, there is an urgent need for developing a more accurate method capable of reliably detecting these hidden abnormalities so that pre-cancer and cancer occurrence can be directly treated at the earliest, and presumably, the most curable stage. The non-invasive nature of time-resolved optical tomography using short pulse laser as used in this research makes it most attractive for early detection of lung cancer and tumor.

Cellular Interrogation Using Fiberoptic Nanobiosensors

(Sponsored by National Science Foundation)

The objective of this research is to design fiber-optic based nano-probes for precise delivery of laser light and for probing desired cellular organelles and study the mechanism of light interaction during low-level laser irradiations of tissues. Nano-probes are produced by drawing or etching the optical fiber tips to submicron size using a micro-puller or hydrofluoric acid bath. Then the fiber tip is coated with metal to minimize the leakage of light through fiber cladding. Laser and LED wavelengths are precisely delivered to different parts of the cell using a fiber nano-probe and the output fluorescence signals from target location is sensed by another fiber nano-probe which is connected to a fluorescent lifetime imaging microscope or photon counter for real-time measurements. Cells and cellular organelles are found to respond to light in a number of ways including rate of cell division, formation of singlet oxygen, and generation of ATP depending upon the light parameters and target location of laser beam.

Selected Publications

"Temporal Analysis of Reflected Optical Signals for Short Pulse Laser Interaction with Nonhomogeneous Tissue Phantoms," Journal of Quantitative Spectroscopy and Radiative Transfer, vol. 93, pp. 337-348, 2005. with A. Trivedi, and S. Basu

"Optical Tomography System Using Short Pulse Laser for Early Lung Cancer," Florida Tech Conference, St. Petersburg, FL, May 17-18, 2004. -- invited paper

"Experimental and Numerical Analysis of Short Pulse Laser Interaction with Tissue Phantoms Containing Inhomogeneities," Applied Optics, vol. 42, no. 25, pp. 5173-5180, 2003. with C. Das, A. Trivedi, and T. Vo-Dihn

"Short Pulse Laser Propagation through Tissues for Biomedical Imaging," Journal of Physics D: Applied Physics, vol. 36, no. 14, pp. 1714-1721, 2003. with C. Das, A. Trivedi, and T. Vo-Dihn

"Discrete Transfer Method Applied to Transient Radiative Transfer Problems in Participating Medium," Numerical Heat Transfer, Part A: Application, vol. 44, pp. 183-197, 2003. with P. Rath, S. C. Mishra, P. Mahanta, and U. K. Saha

"Analysis of Short-Pulse Laser Poton Transport through Tissues for Optical Tomography,"Optics Letters, vol. 27, no. 5, pp. 336-338, 2002. with M. Sakami and T. Vo-Dihn

“Fluorescence Life Time Imaging from Neurons and Organelles during Low Intensity Laser Therapy using Fiber-Optic Nano-Probes,” American Society for Laser Medicine and Surgery Annual Meeting, Boston (Massachusetts), April 5-April 7 (2006). with G. Pal, A. Dutta, M. Grace, I Ilev, R.W. Waynant, & J. Anders