The radiation is divided into 2 major that are the iodine-131 and the cesium - 137. Radioactive iodine-131 has short half life that it will decay in 8 days. When people ingested radiation into the body in high level. It can cause nodules, or cancer of the thyroid. As well as radiation cesium-137 if it can enter the body by ingestion or inhale a continuous for a long time can results in increased risk of cancer