High-resolution optoacoustic imaging from iThera Medical
High-resolution visualization of superficial microvasculature is critical for diagnosis and treatment monitoring of diseases like skin cancers, tumor angiogenesis and vascular disease.
Conventional imaging modalities are able to assess microvasculature only with the help of contrast agents or invasive techniques. RSOM utilizes laser excitation and high-frequency acoustic detection,
thereby providing intrinsic optical tissue contrast, with up to 10 μm resolution, at several millimeters depth.
iThera Medical has developed RSOM imaging systems for explorative preclinical and clinical use. Clinically, RSOM can be utilized to detect diseases in which irregular accumulation of hemoglobin or melanin is involved,
at mesoscopic scales. Preclinically, RSOM can additionally be used to resolve the presence of molecular probes.
Imaging of benign nevus using clinical prototype RSOM
(Left) System setup of the clinical RSOM prototype system. Depicted are the general positioning of all components and the human tissue of a healthy volunteer. (Right) (a) MIP image vertical to the skin surface of a scan region containing a ~1.5 mm benign nevus (b). The intense signal in the RSOM image is a result of high local levels of melanin in the nevus. (c,d) MIP images along the direction perpendicular to the skin surface within the limits marked in (a). In (d) the frequency filtered original image (white) is overlaid with an image filtered for vessels in green.
Preclinical imaging of tumor vasculature
(Top) System schematic of the preclinical RSOM system depicting general positioning of system components and the mouse.
(Bottom) Progression of tumor growth and angiogenesis was monitored with RSOM over 9 days. Maximum intensity projection images 900 μm below the skin surface at four time points (2, 4, 7 and 9 days after implantation) are shown; the insets in each image depict growth of microvasculature between two large vessels (arrows) over time. (Scale bar: 1 mm major images, 0.5 mm inset).
Technical information Axial / lateral resolution: up to 10 / 40 µm Penetration depth: up to 3 mm 80 seconds acquisition time for 5 x 5 mm field of view Pulsed laser illumination at 532 nm (multispectral planned for 2017) 50 MHz single-element detector with ultra-wide bandwidth (>90 percent) Image acquisition fully automated Software for image reconstruction, visualization and analysis