There are a number of ways to attack cancer; one of the most commonly used is radiation therapy. Radiation works on tumors in two ways; firstly, it damages DNA and, secondly, it produces oxygen radicals that also harm cancer cells. However, when oxygen levels are low (hypoxia), the body produces fewer oxygen radicals, meaning that radiation therapy is less effective. Because cancer cells divide so quickly, they require more oxygen than healthy tissue. At the same time, blood vessels within tumors are often poorly constructed, making them less efficient…….