In Paris in 1898, the element Radium was discovered by the two physicists Pierre Curie and Marie Skłodowska-Curie . In collaboration with the physicist Antoine Henri Becquerel, Pierre Curie experimented with radium irradiation on his own body to discover the medical possibilities. In 1901, they published their findings and shortly thereafter the dermatologist Henri Alexandre Danlos in the Hôpital St. Louis in Paris treated a case of subcutaneous lupus with radium irradiation. At this point, Radium therapy had its debut. Radium irradiation was used in the treatment of cancer in many places all over the world. In Paris, Marie Curie and Claudius Regaud opened the "Institut du Radium" in 1913, which became a renowned oncological institute.
Sketch: Radium Plaque, design by Union Minière, Brussels. The radium plaque was placed on the area to be irradiated. The metal holder with handle protected the surroundings from radiation.
Photo: Radium application. Radium tubes are fixed in place with sticking plaster
Figure: The Radium applicator was pressed onto the skin to be irradiated and needed to be held in place with the extended handle.
The element Radium was obtained in very small quantities from the mineral Pitchblende (uranium oxide). It is formed by the radioactive decay of Uranium in a long series of decay products which are quickly formed one after the other. Its medical use is relies on the penetrating Gamma Rays which emanate from these decay products. Photons of at least 10 different energies are emitted in the range of 200 to 2000 keV, with an average energy of ca. 1 MeV. The radiation is only obtained when the Radium is hermetically sealed so that the Radon gas produced and the decay products are preserved. In the form of Radium Bromide, radium is processed into medical applicators such as needles and plaques. In spite of large scale industrial mining, the production of Radium was limited and it took some time before the growing demands of hospitals could be met. Its cost was therefore high and varied between 60 and 180 US$ per milligram (mg).
The demand was high due to the fact that Radium irradiation had advantages over the use of the primitive X-ray irradiation. The radiation from the early X-ray tubes was unstable and had a low energy and intensity. The high-voltage of the oldest X-ray units was well below 100 kV making them only suitable for superficial irradiation. Radium radiation is strong and constant and can be easily dosed. Gamma radiation from a hermetically sealed quantity of Radium has an equivalent energy of around 1 MeV and can penetrate far deeper than the radiation from the weak X-ray units then available. Small applicators or needles containing Radium were also inserted into body cavities, or surgically into tissues - something which was not possible with X-ray tubes.