Radioactive lens does exist after all. Friendly neighborhood lens tinkerer and vintage lens innovator Mathieu Stern tests the radioactive properties of a vintage lens from the 1940's to 1970', which was manufactured with thorium.
Thorium was used to coat on the lens elements and is deemed measurable deadly. In this video, Stern does his everyday routine with the presence of the lens near him --- eating, sleeping, cooking, bathing, and more. For the final test of its toxicity, he tried to burn a plant or moss using the lens.
The preview image was taken from the video.