title: Interstitial photoacoustic sensor for the measurement of tissue temperature during interstitial laser phototherapy.
abstract: Photothermal therapy is an effective means to induce tumor cell death, since tumor tissue is more sensitive to temperature increases than normal tissue. Biological responses depend on tissue temperature; target tissue temperature needs to be precisely measured and controlled to achieve desired thermal effects. In this work, a unique photoacoustic (PA) sensor is proposed for temperature measurement during interstitial laser phototherapy. A continuous-wave laser light and a pulsed laser light, for photothermal irradiation and photoacoustic temperature measurement, respectively, were delivered to the target tissue through a fiber coupler. During laser irradiation, the PA amplitude was measured. The Grüneisen parameter and the bioheat equation were used to determine the temperature in strategic positions in the target tissue. Our results demonstrate that the interstitial PA amplitude is a linear function of temperature in the range of 22 to 55 °C, as confirmed by thermocouple measurement. Furthermore, by choosing appropriate laser parameters, the maximum temperature surrounding the active diffuse fiber tip in tissue can be controlled in the range of 41 to 55 °C. Thus, this sensor could potentially be used for fast, accurate, and convenient three-dimensional temperature measurement, and for real-time feedback and control of interstitial laser phototherapy in cancer treatment.
authors.affiliation: Fujian Provincial Key Laboratory of Photonic Technology, Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, College of Photonic and Electronic Engineering, Fujian Normal University, Fuzhou 350007, China. lizhifang@fjnu.edu.cn.
authors.forename: Zhifang
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Cardiovascular Surgery, Fujian Provincial Hospital, Fujian Medical University, Fuzhou 350000, China. chenhaiyulove2002@aliyun.com.
authors.forename: Haiyu
authors.initials: H
authors.lastname: Chen
authors.affiliation: Biophotonics Research Laboratory, Center for Interdisciplinary Biomedical Education and Research, University of Central Oklahoma, Edmond, OK 73034, USA. fzhou2@uco.edu.
authors.forename: Feifan
authors.initials: F
authors.lastname: Zhou
authors.affiliation: Fujian Provincial Key Laboratory of Photonic Technology, Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, College of Photonic and Electronic Engineering, Fujian Normal University, Fuzhou 350007, China. hli1688@126.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Fujian Provincial Key Laboratory of Photonic Technology, Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, College of Photonic and Electronic Engineering, Fujian Normal University, Fuzhou 350007, China. wchen@uco.edu.|Biophotonics Research Laboratory, Center for Interdisciplinary Biomedical Education and Research, University of Central Oklahoma, Edmond, OK 73034, USA. wchen@uco.edu.
authors.forename: Wei R
authors.initials: WR
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D006801:Humans; D028022:Low-Level Light Therapy / Q000009:adverse effects; D009369:Neoplasms / Q000473:pathology / Q000628:therapy*; D061088:Photoacoustic Techniques / Q000379:methods*; D013057:Spectrum Analysis; D013696:Temperature; D013821:Thermometers