Premium
TU‐C‐220‐05: The Role of Photoacoustic Detection in High‐Intensity Focused Ultrasound Surgery
Publication year - 2011
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3613165
Subject(s) - photoacoustic imaging in biomedicine , high intensity focused ultrasound , thermocouple , therapeutic ultrasound , ultrasound , computer science , thermal ablation , ablation , transducer , ultrasonic sensor , materials science , medical physics , intensity (physics) , acoustics , biomedical engineering , nuclear medicine , medicine , physics , optics , composite material
Purpose: The purpose of this study is to show the feasibility of using photoacoustic imaging to assess thermal ablation outcomes of high intensity focused ultrasound (HIFU) surgery in real‐time. Methods: A photoacoustic imaging system was used to monitor HIFU ablation process in this study. Single‐element, spherically focused ultrasonic transducers with center frequencies of 5 MHz and 10 MHz were used to generate HIFU lesions and detect photoacoustic signals in beef kidney during HIFU treatments, respectively. A T‐type thermocouple was used to measure the temperature rise during the treatment as well. Thermal dose, which was used to indicate the coagulation of soft tissue, was calculated with the temperature measured by the thermocouple. Detected photoacoustic signals were then related to the coagulation of soft tissue through thermal dose calculations. Furthermore, photoacoustic signals from beef kidney coagulating under a constant temperature was obtained to show the changes of photoacoustic signals under a constant temperature during soft tissue coagulation. In addition, in order to enhance the contrast and specificity of photoacoustic imaging, gold nanorods were used as the contrast agents during in vivo experiment. Results: photoacoustic amplitude increases during the HIFU process and tends to have a saturation stage after the soft tissue is completely coagulated, which is indicated by a 240 or more TD43 minutes. Also, a linear relation between photoacoustic amplitude changes and temperature was observed when monitoring the sole effect of temperature. In addition, photoacoustic amplitude changes and finally reached a constant value during soft tissue coagulation under a constant temperature. Conclusions: This work demonstrated that photoacoustic imaging may be used to assess the outcomes of thermal ablation along with ultrasound imaging. Educational Objective: 1. Understand the potential role of photoacoustic detection during HIFU therapy.