ÜDS-Sağlık 2002-1 Soru=73

According to the passage, ionizing radiation -- --.

Ionizing radiation has proved to be most valuable,
for example, in clinical diagnosis and
radiotherapy. However, inadvertent exposure to
relatively high doses of ionizing radiation is
capable of injuring and killing cells, inducing
mutations, producing developmental
abnormalities in fetuses exposed in
utero, or even producing latent cancers. On earth,
it is impossible to escape exposure to radiation.
Cosmic rays bathe the earth continuously, as do
terrestrial concentrations of radionuclides, such as
radon gas. The two constitute natural
"background" radiation. Few humans in
developed countries escape diagnostic X-rays,
and many require radiotherapy as a potential cure
for various types of neoplasia, The "early"
injurious effects of radiation appear only when
certain cumulative levels of exposure to radiation
have been exceeded. However, the later
appearing consequences may have no
thresholds; hence, the public's concern about the
possible carcinogen city of even low-level
exposures.