Health Effects of Gamma radiation
A large portion of gamma radiation largely passes through the body without interacting with tissue. X-rays behave in a similar way, but have slightly lower energy. By contrast, alpha and beta particles inside the body lose all their energy by colliding with tissue, causing damage.
Gamma rays can ionize atoms in tissue directly or cause what are known as "secondary ionizations". Because of the gamma ray's penetrating power and ability to travel great distances, it is considered the primary hazard to the general population during most radiological emergencies. In fact, when the term "radiation sickness" is used to describe the effects of large exposures in short time periods, the most severe damage almost certainly results from gamma radiation.
More about the radioactive isotope testing of uranium, iodine and cesium via gamma spectroscopy you can read on our information sheet.