Doctors at London's Westminster Hospital exploring the use of radiation to treat cancer devised this experimental radium 'bomb', as they called it. It was the fourth in a sequence of devices intended to treat tumours at a distance. They considered that one gram of radium held a few inches from the tumour might be more effective than the more usual procedure of placing smaller amounts as close as possible to the cancer in radium-filled needles.

Like much experimental medical apparatus, this equipment was made in the hospital's own workshops. The operator exposed the patient's tumour to the radium within the egg-shaped lead treatment head, using a shutter operated via a bicycle brake cable.

Radium, painstakingly extracted from poorly-yielding pitchblende ore, was very expensive. The 'bomb' allowed more effective use of this scarce material.

Inv. A639472