title: Combined frequency domain photoacoustic and ultrasound imaging for intravascular applications.
abstract: Intravascular photoacoustic (IVPA) imaging has the potential to characterize lipid-rich structures based on the optical absorption contrast of tissues. In this study, we explore frequency domain photoacoustics (FDPA) for intravascular applications. The system employed an intensity-modulated continuous wave (CW) laser diode, delivering 1W over an intensity modulated chirp frequency of 4-12MHz. We demonstrated the feasibility of this approach on an agar vessel phantom with graphite and lipid targets, imaged using a planar acoustic transducer co-aligned with an optical fibre, allowing for the co-registration of IVUS and FDPA images. A frequency domain correlation method was used for signal processing and image reconstruction. The graphite and lipid targets show an increase in FDPA signal as compared to the background of 21dB and 16dB, respectively. Use of compact CW laser diodes may provide a valuable alternative for the development of photoacoustic intravascular devices instead of pulsed laser systems.
authors.affiliation: Medical Biophysics, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada; Imaging Research, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
authors.forename: Robin F
authors.initials: RF
authors.lastname: Castelino
authors.affiliation: Imaging Research, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Hynes
authors.affiliation: Medical Biophysics, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada; Imaging Research, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
authors.forename: Chelsea E
authors.initials: CE
authors.lastname: Munding
authors.affiliation: PHAST Imaging, 1B Richview Road, Toronto, ON M9A 4M6, Canada.
authors.forename: Sergey
authors.initials: S
authors.lastname: Telenkov
authors.affiliation: Medical Biophysics, University of Toronto, 5 King's College Road, Toronto, ON M5S 3G8, Canada; Imaging Research, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5, Canada.
authors.forename: F Stuart
authors.initials: FS
authors.lastname: Foster
keywords: (170.5120) Photoacoustic imaging; (170.7170) Ultrasound