title: Effect of irradiation distance on image contrast in epi-optoacoustic imaging of human volunteers.
abstract: In combined clinical optoacoustic (OA) and ultrasound (US) imaging, epi-mode irradiation and detection integrated into one single probe offers flexible imaging of the human body. The imaging depth in epi-illumination is, however, strongly affected by clutter. As shown in previous phantom experiments, the location of irradiation plays an important role in clutter generation. We investigated the influence of the irradiation geometry on the local image contrast of clinical images, by varying the separation distance between the irradiated area and the acoustic imaging plane of a linear ultrasound transducer in an automated scanning setup. The results for different volunteers show that the image contrast can be enhanced on average by 25% and locally by more than a factor of two, when the irradiated area is slightly separated from the probe. Our findings have an important impact on the design of future optoacoustic probes for clinical application.
authors.affiliation: Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Held
authors.affiliation: Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Preisser
authors.affiliation: Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: H Günhan
authors.initials: HG
authors.lastname: Akarçay
authors.affiliation: Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Sara
authors.initials: S
authors.lastname: Peeters
authors.affiliation: Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Frenz
authors.affiliation: Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Jaeger
keywords: (170.3880) Medical and biological imaging; (170.5120) Photoacoustic imaging; (170.7170) Ultrasound