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11 November 2005 NMPPAS fiber optic microprobe for sub-surface brain tumor diagnosis
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Proceedings Volume 6007, Smart Medical and Biomedical Sensor Technology III; 60070P (2005)
Event: Optics East 2005, 2005, Boston, MA, United States
Brain cancer affects approximately 16,500 people a year and individuals diagnosed with glioblastoma multiforme have an average life expectancy of less than 12-18 months after diagnosis. A portable fiber-optic probe capable of distinguishing between healthy and tumor tissues, with a high degree of spatial resolution, deep within a sample would be a valuable tool for tumor diagnosis and margining. A novel technique that combines 1-2 cm penetration depths with cellular level spatial resolution to chemically distinguish cancerous from non-cancerous tissues is non-resonant multiphoton photoacoustic spectroscopy (NMPPAS). This technique focuses pulsed near infrared light into a sample, creating a two-photon excitation event, and measures the resulting non-radiative decay as an ultrasonic signal. This paper discusses the optimization of a portable fiber-optic NMPPAS probe capable of delivering nanosecond laser pulses from 740nm-1100nm to a series of lens, which focus the light into the sample. The resulting ultrasonic signal is measured using a polyvinylidene fluoride based piezoelectric detector. The two-photon excitation efficiency of the portable NMPPAS probe system has been evaluated by measuring the two-photon excitation and emission spectra of common fluorescent dyes such as rhodamine B and fluorescein. In addition, this paper also demonstrates the diagnostic potential of this technique for tumor detection and margining without the need for acquisition of an entire spectrum.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John B. Kiser, Nirmala Chandrasekhran, and Brian M. Cullum "NMPPAS fiber optic microprobe for sub-surface brain tumor diagnosis", Proc. SPIE 6007, Smart Medical and Biomedical Sensor Technology III, 60070P (11 November 2005);

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