1. National Institute for Advanced Industrial Science and Technology, 16-1, Onogawa, Tsukuba 305-8569, Japan
2. Iwate Medical University Cyclotron Center, Tomegamori, Takizawamura, Iwategun 020-0173, Japan
3. Sans Frontiere Progres, P. O. Box 46/468, Ulaanbaatar-46, Mongolia
4. Center for Environment Health and Human Ecology, Public Health Institute, Ministry of Health, Mongolia