Among other things, their equipment can be triggered by industrially used radiation sources, radiation therapy patients, and radium paint on old clocks and instruments.
From the thenewstribune.com
This rare isotope has potential applications in radiation therapy and is most efficiently produced by bombarding a radium-226 target with 20-30 MeV deuterium ions.
From the en.wikipedia.org
Radiation therapy for prostate cancer was first developed in the early 20th century and initially consisted of intraprostatic radium implants.