title: Photoacoustic imaging and temperature measurement for photothermal cancer therapy.
abstract: Photothermal therapy is a noninvasive, targeted, laser-based technique for cancer treatment. During photothermal therapy, light energy is converted to heat by tumor-specific photoabsorbers. The corresponding temperature rise causes localized cancer destruction. For effective treatment, however, the presence of photoabsorbers in the tumor must be ascertained before therapy and thermal imaging must be performed during therapy. This study investigates the feasibility of guiding photothermal therapy by using photoacoustic imaging to detect photoabsorbers and to monitor temperature elevation. Photothermal therapy is carried out by utilizing a continuous wave laser and metal nanocomposites broadly absorbing in the near-infrared optical range. A linear array-based ultrasound imaging system is interfaced with a nanosecond pulsed laser to image tissue-mimicking phantoms and ex-vivo animal tissue before and during photothermal therapy. Before commencing therapy, photoacoustic imaging identifies the presence and spatial location of nanoparticles. Thermal maps are computed by monitoring temperature-induced changes in the photoacoustic signal during the therapeutic procedure and are compared with temperature estimates obtained from ultrasound imaging. The results of our study suggest that photoacoustic imaging, augmented by ultrasound imaging, is a viable candidate to guide photoabsorber-enhanced photothermal therapy.
authors.affiliation: University of Texas at Austin, Department of Biomedical Engineering, Austin, Texas 78712, USA.
authors.forename: Jignesh
authors.initials: J
authors.lastname: Shah
authors.forename: Suhyun
authors.initials: S
authors.lastname: Park
authors.forename: Salavat
authors.initials: S
authors.lastname: Aglyamov
authors.forename: Timothy
authors.initials: T
authors.lastname: Larson
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Konstantin
authors.initials: K
authors.lastname: Sokolov
authors.forename: Keith
authors.initials: K
authors.lastname: Johnston
authors.forename: Thomas
authors.initials: T
authors.lastname: Milner
authors.forename: Stanislav Y
authors.initials: SY
authors.lastname: Emelianov
mesh_terms: D000818:Animals; D006979:Hyperthermia, Induced / Q000379:methods*; D033401:Microscopy, Acoustic / Q000379:methods*; D009369:Neoplasms / Q000175:diagnosis* / Q000628:therapy*; D019047:Phantoms, Imaging; D010789:Phototherapy / Q000379:methods*; D013552:Swine; D013813:Therapy, Computer-Assisted / Q000379:methods*; D013817:Thermography / Q000379:methods*