Imaging 9 L tumors with and without the <i>lacZ</i> reporter gene by an array-based photoacoustic and ultrasonic imaging system <i>in vivo</i>.

<p>(a) Photograph of a tumor-bearing mouse before imaging. (b) Post-euthanasia photograph of the <i>lacZ</i>- and <i>lacZ</i>+ tumors after removing the skin above. (c, d, e) Composite photoacoustic and ultrasonic images shown in (c) three-dimensional visualization, (d) a typical B-scan, and (e) the maximum amplitude projection view on the skin. (f) B-scan image of the <i>lacZ</i>-marked tumor at a 5-cm depth in biological tissue, acquired by overlaying chicken breast tissue on top of a mouse. Photoacoustic images are colored green, while ultrasonic images are in gray. The scale bars represent 5 mm.