ABSTRACT
The best evidence to date suggests that low radiation doses from X-ray imaging procedures may carry a small risk of causing a radiation-induced cancer (National Research Council 2006). Both mammography (see Chapter 19 of this book) and breast tomosynthesis (see Chapter 20) typically have higher radiation doses than simple chest radiography, but lower than most CT procedures (see Chapter 29 for more on radiation dose in mammography and tomosynthesis). In a breast cancer screening program, in which most women are expected to never develop the disease, the risk of inducing a cancer is a small, but important concern. In this chapter, the biological effects of ionizing radiation are introduced, as well as the concepts of excess risk and the benefits of breast cancer screening. Several groups have attempted to establish an estimate of radiation risk in a modern screening program, and a comparison of their approaches is presented. Finally, recent trends in radiation dose levels in screening mammography and breast tomosynthesis are described.
