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Biomedical subjects

R J de Vos

Publications and source records attributed to R J de Vos.

5 recordsLinked to original sources
PubMed1995

Double-film technique for the determination of the homogeneity of line sources.

A new technique is presented for determining the homogeneity of the linear activity. The method uses two x-ray films that are firmly pressed against opposing sides of a needle containing a radioactive line source. The homogeneity of the linear activity of 68 iridium-192 wires has been measured. About 80% of the measured linear activities showed deviations of no more than 5% from the mean; about 20% of the measured linear activities showed deviations of 5%-10% from the mean. Individual wires may contain deviations of 5% or more extended over several centimeters, which causes the dose in the prescription point to deviate 5% from the desired value. Four wires (8%) were rejected for this reason.

Biophysical Phenomena↗
PubMed1995

A straightforward implantation method of radioactive sources by means of the Leksell frame.

Stereotactic brachytherapy of cerebral gliomas often involves insertion of catheters through the tumor bed. We adopted the hexagonal tube configuration around a central tube. Such a configuration is applicable to most commonly occurring brain tumors. In order to perform a low-cost, accurate and straightforward implantation, a robust mathematical derivation of all relevant formulas is used to transform CT coordinates to Leksell frame coordinates, including derivations for the two stereotactic angles. The coordinates of the seven tubes (which are essential if no template is available) and the length of the radioactive source are also derived, and an example is presented. The calculations have been implemented on a personal computer (Intel processor 386 or higher). Additional options, such as choosing other stereotactic angles than the calculated ones and rotating the tube configuration around the central tube, are integrated into the program.

Brachytherapy↗