title: A measurement and modeling study of temperature in living and fixed tissue during and after radiofrequency exposure.
abstract: Fluorescent intensity of the dye Rhodamine-B (Rho-B) decreases with increasing temperature. We show that in fresh rat brain tissue samples in a custom-made radiofrequency (RF) tissue exposure device, temperature rise due to RF radiation as measured by absorbed dye correlates well with temperature measured nearby by fiber optic probes. Estimates of rate of initial temperature rise (using both probe measurement and the dye method) accord well with estimates of local specific energy absorption rate (SAR). We also modeled the temperature characteristics of the exposure device using combined electromagnetic and finite-difference thermal modeling. Although there are some differences in the rate of cooling following cessation of RF exposure, there is reasonable agreement between modeling and both probe measurement and dye estimation of temperature. The dye method also permits measurement of regional temperature rise (due to RF). There is no clear evidence of local differential RF absorption, but further refinement of the method may be needed to fully clarify this issue.
authors.affiliation: Australian Centre for Electromagnetic Bioeffects Research, Brain and Psychological Sciences Research Centre (BPsyC), Swinburne University of Technology, Hawthorn, Australia.
authors.forename: Jacqueline F
authors.initials: JF
authors.lastname: Bermingham
authors.forename: Yuen Y
authors.initials: YY
authors.lastname: Chen
authors.forename: Robert L
authors.initials: RL
authors.lastname: McIntosh
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Wood
mesh_terms: D000042:Absorption; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects*; D002138:Calibration; D003198:Computer Simulation; D055590:Electromagnetic Phenomena; D005336:Fiber Optic Technology; D005456:Fluorescent Dyes / Q000494:pharmacology; D066298:In Vitro Techniques; D008959:Models, Neurological; D011846:Radio Waves; D051381:Rats; D012235:Rhodamines / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D012235:Rhodamines; C029773:rhodamine B
keywords: laser scanning confocal microscopy; microdosimetry; rat brain slices; temperature sensing