title: Application of a temperature-dependent fluorescent dye (Rhodamine B) to the measurement of radiofrequency radiation-induced temperature changes in biological samples.
abstract: We have applied a non-contact method for studying the temperature changes produced by radiofrequency (RF) radiation specifically to small biological samples. A temperature-dependent fluorescent dye, Rhodamine B, as imaged by laser scanning confocal microscopy (LSCM) was used to do this. The results were calibrated against real-time temperature measurements from fiber optic probes, with a calibration factor of 3.4% intensity change degrees C(-1) and a reproducibility of +/-6%. This non-contact method provided two-dimensional and three-dimensional images of temperature change and distributions in biological samples, at a spatial resolution of a few micrometers and with an estimated absolute precision of around 1.5 degrees C, with a differential precision of 0.4 degree C. Temperature rise within tissue was found to be non-uniform. Estimates of specific absorption rate (SAR) from absorbed power measurements were greater than those estimated from rate of temperature rise, measured at 1 min intervals, probably because this interval is too long to permit accurate estimation of initial temperature rise following start of RF exposure. Future experiments will aim to explore this.
authors.affiliation: Faculty of Life and Social Sciences, Cellular Neuroscience Laboratory, Brain Sciences Institute, Swinburne University of Technology, Hawthorn, VIC, Australia.
authors.forename: Yuen Y
authors.initials: YY
authors.lastname: Chen
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Wood
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000502:physiology* / Q000528:radiation effects*; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D011829:Radiation Dosage; D011846:Radio Waves; D051381:Rats; D012235:Rhodamines; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013623:Tail / Q000502:physiology* / Q000528:radiation effects*; D013817:Thermography / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D012235:Rhodamines; C029773:rhodamine B