title: Decay of photoacoustic signals from biological tissue irradiated by near infrared laser pulses.
abstract: We describe the phenomenon of a sudden decrease in the amplitude of photoacoustic signals arising from nanosecond laser pulse irradiation of biological samples, measured in vitro. Several dental enamel and chicken/turkey breast samples are examined. Moderate optical energy densities (i.e., about 300 mJ/cm2) are used, typical of those exploited in photoacoustic investigations. Measurements show a rapid decay of photoacoustic signals within the first few laser pulses absorbed by the sample. This phenomenon indicates that laser irradiation interacts with biological samples, causing long-term physical changes that can be attributed to a reduction of optical absorption within the samples.
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester, PO Box 88, Sackville Street, Faraday Tower, Manchester M60 1QD, United Kingdom. Grzegorz.Gondek@manchester.ac.uk
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Gondek
authors.forename: Teng
authors.initials: T
authors.lastname: Li
authors.forename: Richard J M
authors.initials: RJ
authors.lastname: Lynch
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Dewhurst
mesh_terms: D000162:Acoustics; D000818:Animals; D001940:Breast / Q000502:physiology*; D002645:Chickens; D003198:Computer Simulation; D003743:Dental Enamel / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007259:Infrared Rays; D007700:Kinetics; D007834:Lasers; D008954:Models, Biological; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D012542:Scattering, Radiation