Radiation-Free

Researchers from Stanford University School of Medicine and Lucile Packard Children’s Hospital, Stanford have devised a magnetic resonance imaging (MRI) technique to scan young cancer patients’ bodies for tumours without exposing them to harmful radiation. Currently doctors use the quick responding positron emission tomography-computed tomography (PET-CT) method to gather information. Unfortunately, PET-CT exposes patients to radiation that is equivalent to 700 X-rays, an effect that could result in secondary cancers in later life.

Several physicians try using MRIs to scan for tumours. However, a full body scan takes as long as two hours. In addition, the MRI does not distinguish between healthy and cancerous tissue, as the contrast agents (chemicals injected into body to make tumours visible) do not stay in the tissues for too long. To overcome this problem, the Stanford team used a new contrast agent consisting nanoparticles of iron.

These nanoparticles are retained in the body for many days. Moreover, they reveal tumours by making the healthy bone marrow, lymph nodes, liver and spleen appear dark. These nanoparticles make blood vessels appear brighter, thus giving vital clues about the location of tumour. Researchers after testing the modified MRI in 22 patients compared its results with that of PET-CT and found that out of 174, PET-CT detected 163 whereas the former detected 158 tumours.