Three-dimensional photoacoustic imaging with a clinical two-dimensional matrix ultrasound transducer
Photoacoustic tomography provides both structural and functional imaging in vivo based on optical absorption contrast. A novel imaging system that incorporates a two-dimensional matrix ultrasound probe for combined photoacoustic and ultrasonic three-dimensional (3D) volumetric imaging is presented. The system consists of a tunable dye laser pumped by a Nd:YAG laser, a commercial ultrasound imaging system (Philips iU22) with a two-dimensional matrix transducer (Philips X7-2, 2500 elements, 2-7 MHz), and a multichannel data acquisition system which allows us to acquire RF channel data. Compared with alternative 3D techniques, this system is attractive because it can generate co-registered 3D photoacoustic and ultrasound images without mechanical scanning. Moreover, the lateral resolution along the azimuth and elevational directions are measured to be 0.77 ± 0.06 mm and 0.96 ± 0.06 mm, respectively, based on reconstructed photoacoustic images of phantoms containing individual human hairs. Finally, in vivo 3D photoacoustic sentinel lymph node mapping using methylene blue dye in a rat model is demonstrated.
Additional Information© 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). This research was supported by National Institutes of Health grants U54 CA136398 (Network for Translational Research), R01 EB000712, R01 NS46214, and R01 EB008085. LVW has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work. TNE, LJ, and JR are employees of Philips Research.
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