Radionuclides may also be produced artificially in particle accelerators or nuclear reactors, resulting in 650 of these with half-lives of over an hour, and several thousand more with even shorter half-lives.
放射性同位素也可能是因為粒子加速器或核反應爐而人工合成，其中有650種的半衰期超過一小時，有數千種的半衰期更短。