Simultaneous imaging of drug delivery with SPIO-based MRI and drug therapy with pHe readout from BIRDS

Since acidification of the extracellular environment is a hallmark of cancer pathogenesis, successful therapy may manifest as normalization of pHe. We have shown that quantitative pHe measurement is possible with BIRDS is possible even in the presence of superparamagnetic iron oxide nanoparticles (SPIO-NPs). Because SPIO-NPs have been used to image and track drug delivery, we envisage co-injection of BIRDS agents and NPs, containing drugs and SPIO, as a new protocol that can track drug delivery to tumors, concurrently map tumor location and size (by MRI), and at the same time measure therapeutic efficacy through changes in tumor pH (by BIRDS).