Author/Authors :
Banari Bahnamiri، S نويسنده PhD student of nuclear physics, Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran , , Miri Hakimabad، S H نويسنده Professor of nuclear physics, Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran , , Izadi Najafabadi، R نويسنده Associate Professor of nuclear physics, Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran ,
Abstract :
Background: The potential hazards of exposure to radiation from radon have been
of great concern worldwide, as it is associated with an increased risk of lung cancer.
Radon (222Rn) and its progeny are the main sources of radioactivity in the environment.
The half-life of 222Rn (3.82 days) is long enough for it to diffuse into and build
up in homes. 220Rn or thoron from the 232Th series, and 219Rn—a decay product of
235U—have very short half-lives (55.6 and 3.96 sec, respectively) and are of minor
significance compared to 222Rn in the 238U series. However, these sources, like thoron,
are important in uranium mines. Radon and thoron progeny decay by emitting B particles
accompanied by ? radiation. Although ? rays are comparatively less damaging
to the respiratory system than ? and B particles, it is the principal deposited energy in
other organs.
Methods: Comparison of radon and thoron ? radiation dosimetry was performed
using a modified Oak Ridge national laboratory (ORNL) adult mathematical phantom
and the Monte Carlo N-particle transport code (MCNP).
Results: The results showed that the highest amount of the absorbed dose was in
the lung followed by the thymus and heart, according to the ICRP103 publication.
Conclusions: The absorbed dose from thoron was quite large in comparison to
radon because thoron has more high-energy particles than radon.
