Microbubbles conjugated to small peptide- targeting ligands can provide ultrasound imaging signals allowing researchers to visualize tumor activity at the molecular level and show its progression, according to research published in the March issue of the Journal of Nuclear Medicine.
In the study, researchers intravenously injected integrin-binding knottin peptides conjugated to the surface of microbubbles in 42 mice bearing human ovarian adenocarcinoma xenograft tumors.
Juergen K. Willmann, MD, lead author of the study and assistant professor of radiology at Stanford University, and colleagues demonstrated that microbubbles conjugated to integrin-binding knottin peptides provided ultrasound imaging signals higher than those provided by a large antibody molecule.
The imaging signals produced by the microbubbles were reflected back to the ultrasound transducer and the areas that outline the tumor were illuminated, thus providing researchers with a sonogram of tumor vessel growth on a molecular level.
"We hope this technique might be helpful for the early detection of disease," said Willmann. "It may help save lives by finding cancer—such as breast, ovarian or pancreatic cancer—in the very early stages, when it is still curable."
"Ultrasound holds great promise for the application of molecular imaging because it is widely available, relatively inexpensive and safe. There is no exposure to radiation and repetitive imaging is not a concern," said Willmann. "Furthermore, the targeted microbubbles have great potential for translation from bench to bedside—which will be explored in future studies," said Sanjiv S. Gambhir, MD, PhD, director of the molecular imaging program at Stanford.