Ultrasound Power Doppler images (following the intravenous injection of a contrast agent) of a subcutaneous melanoma in a mouse before and after treatment with mild ultrasound. Blood flow to the tumor is represented in color. In the pre-treatment image (a), the tumor enclosed by dotted region is fully perfused. In the post-treatment (three min at 2.3 W cm-2) image (b), there is a reduction in the perfusion of the tumor, but perfusion is still visible in the surrounding normal tissue. In comparing images (a) and (b), it appears that the effect of insonation was to reduce the access of the contrast agent to the tumor blood vessels, while access was maintained in the blood vessels in the surrounding normal tissues.

Image Credit: Sara Ansaloni, University of Pennsylvania School of Medicine