Ionizing radiation sole cause of chronic myelogenous leukemia. The mechanism by which this occurs is well understood, but quantitative models predicting the level of risk remain controversial. The most widely accepted model posits that the incidence of cancers due to ionizing radiation increases linearly with effective radiation dose at a rate of 5.5% per sievert. If this linear model is correct, then natural background radiation is the most hazardous source of radiation to general public health, followed by medical imaging as a close second. Other stochastic effects of ionizing radiation are teratogenesis, cognitive decline, and heart disease. The table below shows radiation
Samut Prakan radiation accident symbol. Although the symbol was displayed on the teletherapy head, none of those handling the device were aware of its meaning, nor were there written warnings in Thai. Together with the International Organization for Standardization (ISO), the IAEA developed a new symbol that would serve as an intuitive warning for large sources of ionizing radiation. The new symbol was published in 2007 as ISO 21482, and is intended to accompany the trefoil on internal components of devices containing dangerous sources to prevent persons from unknowingly disassembling them. In Thailand, however, substantial efforts to prevent further such occurrences had not materialized