The hydrogen-isotope exchange reaction (T-for-H exchange reaction) between tritium-labeled poly (vinyl alcohol) and each cycloamine dissolved in 1, 4-dioxane has been observed at 50-90°C. Consequently, the quantitative relation was obtained between the reaction time and the increase in the tritium activity of the cycloamine. The reaction was dynamically analyzed with both the A''-McKay plot method and data observed. Moreover, in order to clarify the effect of the relative atomic charge of the N atom (in the amino group) on the reactivity of the cycloamine, the MOPAC method was introduced. As to cycloamine, the following three matters have been consequently found in the T-for-H exchange reaction: (1) the reactivity of each cycloamine decreases with increasing the number of carbon atoms in the ring of cycloamine, (2) the rate constant (k) for each cycloamine depends on the reaction temperature, (3) the correlation is found between the relative atomic charge of the N atom in the NH2group and k for the cycloamine.
Recently, the number of clinical PET centers is increasing all over Japan. For this reason, the monitoring and control of radiation exposure of employees, especially nurses, in PET-dedicated clinics and institutions are becoming very important issues for their health. We measured the radiation exposure doses of the nurses working at Nisidai Diagnostic Imaging Center, and analyzed the exposure data obtained from them. The exposure doses of the nurses were found to be 4.8 to 7.1 mSv between April 2003 and March 2004. We found that the nurses were mostly exposed to radiation when they had to have contact with patients received an FDG injection or they had trouble with the FDG automatic injection system. To keep radiation exposure of nurses to a minimum we reconfirmed that a proper application of the three principles of protection against radiation exposure was vital.