Doses in human organs due to alpha, beta and gamma radiations emitted by thoron progeny in the lung.

This work consists of two parts. In the first part, the doses in the human lung per unit exposure to thoron progeny, the dose conversion factor (DCF), was calculated. Dependence of the DCF on various environmental and subject-related parameters was investigated. The model used in these calculations was based on ICRP 66 recommendations. In the second part, the human lungs were considered as the source of beta and gamma radiation which target the other organs of the human body. The DCF to other organs was obtained as 20 µSv WLM(-1), which is larger than the DCF for radon progeny, which was 13 µSv WLM(-1). This is a consequence of the longer half-life of the relevant thoron progeny than that of the radon progeny. It is interesting to note that after the lungs, where the radiation source is actually located, muscle tissue receives the largest dose.