Acoustic radiation force and optical spectroscopy for assessing tumor vessel normalization during anti-angiogenic therapy.

Molecular oxygen is the best known mediator of radiation damage during radiation therapy. This paper investigates techniques for enhancing tumor oxygenation by use of anti-angiogenic therapy for better radiosensitivity. A noninvasive monitoring technique, Acoustic radiation force (ARF)-induced optical spectroscopy, was proposed in this paper to track tumor oxygen changes during anti-angiogenic therapy. Male NCR-NUM nude mice bearing human U87 glioblastoma (ATCC) xenografts on the right hind limb were used for the study. An anti-angiogenic regimen using the drug AZD2171 (AsraZeneca) was found capable of improving tissue oxygenation during the first week of drug treatment. The optical spectroscopy technique was shown to be able to track tumor oxygenation changes during anti-angiogenic therapy, as verified by direct pO2 measurement. By using anti-angiogenic therapy to improve tumor oxygenation prior to radiotherapy, tissue oxygenation may be altered in a way that favors radiation therapy.