One of the reasons that chemotherapy and radiation can fail to kill of the cells in a tumor is because the middle of tumors often have decreased levels of oxygen. Oxygen helps the treatments to do their jobs. To overcome this barrier, researchers have developed tiny oxygen generators that can be implanted in tumors. The generators are able to split water to produce oxygen within the tumor tissue. Using a pancreatic tumor model, the researchers showed that they could rapidly increase the levels of oxygen in tumors.