Patient release criteria following radioactive iodine-131 treatment in the light of international practice: where does South Africa fit in?

The release from hospital of patients treated with radioactive iodine-131 (I) remains a controversial issue as a result of the range of guidelines implemented by national regulatory bodies responsible for radiation protection in various countries worldwide. The aim of this study was to review and analyse the literature on patient release criteria (PRC) applied internationally in an attempt to achieve a justifiable approach to setting equivalent criteria in South Africa. In 2016, the South African Department of Health, Directorate: Radiation Control added conditions (numbers 50 and 90), to licences to use radioactive nuclides. These conditions state that patients must be hospitalized when the dose rate at 1 m is above 25 µSv/h, or more than 555 MBq of iodine-131 was administered to the patient. However, these criteria do not consider patients' socioeconomic conditions. A literature survey was carried out of articles detailing PRC from high-income countries as well as those in the middle-income and lower-income groups. Socioeconomic conditions within countries were determined using the International Monetary Fund lists of gross domestic product. The results from the literature have shown that in setting PRC, several countries have considered the socioeconomic conditions prevailing in their countries to achieve harmony between public protection and cost associated with hospitalization. The South African authority conditions must be seen in the context of the approach followed by other countries. Considering the international context, a justifiable, and potentially implementable, guideline or policy for improving individualized and more caring patient management is advocated.

Biodistribution (as determined by the radiolabelled equivalent) of a gold(III) bis(pyrrolide-imine) Schiff base complex: a potential chemotherapeutic.

The biodistribution of an N2 N2 ' tetradentate gold(III) chelate, which is known to be cytotoxic towards a range of human cancer cell lines, was determined by a radiolabelled equivalent of the compound. The (198) Au-labelled gold(III) chelate of a bis(pyrrolide-imine) Schiff base ligand with a three-carbon di(azomethine) linkage was successfully synthesised with a high radiochemical yield of 73% and radiochemical purity of >95%. The high energy γ-ray emitted by the (198) Au nucleus was used to follow the biodistribution of the compound in vivo in six male Sprague Dawley rats on a gamma camera. The log Po/w value of the (nat) Au analogue, -1.92(2), showed that the compound is hydrophilic and therefore likely to largely remain in the blood pool. This was confirmed by the biodistribution study, which showed 21% of the injected dose (ID) remained in the blood pool 4.5 h after injection. This decreased to 10.8% over a 24-h period. The activity measured in the lungs, 1.48%ID/g, remained relatively constant over a 24-h period suggesting that the complex had accumulated in the lungs in the form of particulates, and could not be cleared by the test subjects. The t½ for the heart and lungs was greater than 24 h. Excretion of the test compound is seemingly via the kidneys, but is slow with approximately 30% of the ID excreted within 24 h.