Turan Unak | PubMed Health

PubMed2003

Some microdosmetric data on Astatine-211.

Radionuclides which emit short range, high LET radiations such as alpha and Auger electrons have very promising applications in cancer therapy. Such radionuclides should eventually be incorporated into cell nuclei to achieve high radiotoxic effectiveness. This means that the dose distribution within the cell nucleus at microscopic levels is very important for comparison of the real differences between the radiotoxic effectiveness of different radionuclides. An experimental setup to determine real dose absorption on the microscopic scale is extremely difficult to design. For this reason, calculation procedures for microscopic dose absorption are of special interest for the diagnostic and therapeutic applications of radionuclides which emit short-range and high LET radiations. A specific calculation method for microscopic energy absorptions within the cell nucleus from Auger electrons of 125I was described earlier. In this study, the radiotoxic effectiveness of 211At and 125I has been compared using the data obtained by this calculation method. The data obtained show clearly that the radiotoxicity of the alpha and Auger emitter radionuclide 211At is comparable to that of 125I.

Alpha Particles↗

PubMed2003

Transfer of orally administrated iodine-131 into chicken eggs.

Radioactive iodine-131 as both as free iodide (Na131I) and covalently bound to aniline (aniline-131I) was added to the drinking water of two Leghorn laying hens as a single dose and also as a cumulative dose over 1 week. The radioactivity of the principal parts of the eggs, i.e. shell, white, and yolk, was measured, and the radioactivity levels per gram material, and percent of the total radioactivity were calculated. The radioactivity measurements were continued for 1 month following the administration of 131I. In the case of the single dose administration, the results obtained showed that about 15% of the total radioactivity administered as Na131I was transported into the egg structure; compared to only about 1% for aniline-131I. After cumulative administration, about 15% of the total administered radioactivity was transported into the egg structure with both forms of 131I. This was probably because of metabolic cleavage of iodine bonds in the labeled aniline molecules during the longer period of exposure. These results also showed considerable accumulation of 131I in the egg yolks. In the case of the single dose administration, 131I can be detected in eggs up to about 20 days after administration, and up to about 30 days, in the case of the cumulative administration over 1 week.

Administration, Oral↗