Biodistribution of 6-[211At]astato-2-methyl-1,4-naphthoquinol bis(diphosphate salt) and 211At- in mice with a transplanted rectal adenocarcinoma.
6-[211At]astato-MNDP is currently being investigated as a potential high LET endoradiotherapeutic drug. Biodistribution and whole-body radiation retention studies have been carried out with 6-[211At]astato-MNDP and 211At- in a murine rectal tumour model; results indicate that the 211At-C bond in the compound is metabolically stable for at least 6 h. The Mean Biological Concentration of 6-[211At]astato-MNDP in tumour tissue ranged from 170-253% over an initial 12 h period; this was higher than that observed for the [211At]astatide anion. Conversely, the uptake of compound into radiobiologically critical organs was significantly lower.
Tracer Studies of Potential Radiosensitizing Agents. Tetrasodium 2-14C-Methyl-1:4-Naphthohydroquinone Diphosphate
IF a non-toxic compound could be found which would concentrate selectively in tumour tissue and which would also increase the sensitivity of cells towards X-rays, it might be of use in the treatment of malignancy. This search for a radio-sensitizer has been the concern of these laboratories for a number of years, and initial studies have been mainly concerned with tetrasodium 2-methyl-I: 4naphthohydroquinone diphosphate (I). The compound has several biological actions of interest. It is a synthetic Vitamin K substitute (Synkavit) by virtue of its ready dephosphorylation and oxidation to 2-methyl-1: 4-naphthoquinone, but it also affects mitoses in cultures of chick fibroblasts (Mitchell and Simon-Reuss, 1947). It increases the antimitotic and chromosome fragmentation effects of X-irradiation on tissue cultures (Mitchell anid Simon-Reuss, 1947, 1952a, 1952b) and also increases tumour retrogression by X-rays in rats bearing a Walker carcinoma (Mitchell, 1954). A small but useful increase in the survival time of patients undergoing X-ray therapy for inoperable carcinoma of the lung has also been reported (Mitchell, 1953). Furthermore, Mitchell (1954) has observed that after an injection of (I) into the rat, some internal organs, if dissected and treated with alkaline hydrogen peroxide, show a brilliant yellow fluorescence in ultra-violet light; the fluorescence is especially strong on the growing edge of the tumour. It seemed likely that this indicated local accumulations of 2-methyl-I:4-naphthoquinone-2: 3-oxide (II) derived from (I). Further information on possible selective concentration was therefore sought by studying the metabolism of (I) labelled with 14C in the methyl group.
The preparation of aromatic astatine compounds through aromatic mercury‐compounds
Aromatic astatine compounds can be prepared under mild conditions in high yields by reaction of astatine with aromatic mercury compounds. 
 
Compared to direct electrophilic astatination this procedure is an easy and clean method for the introduction of astatine in aromatic compounds.