In 1934 one of us (L. H.) with A. Fisher1 published a short communication on the use of direct roentgen irradiation of intra-oral tumors with a home-made, somewhat clumsy apparatus designed by him and put in use in 1932 independently and without knowledge of any similar work elsewhere. The chief disadvantage of this apparatus was the length of time required to obtain the desired dose.
Later we became acquainted with a specially designed roentgen ray unit which serves the purpose of intracavitary irradiation much better than the aforementioned apparatus and has for an additional purpose simulation with roentgen ray energy of the effects of radium. It is known as the Chaoul contact therapy unit. In September 1936 we installed such an apparatus and have been greatly impressed with its value. We feel confident that the present report is justified, because it calls attention to an efficient and powerful agent
HOLLANDER L, SHELTON JM. THE SUPERFICIAL INTRA-ORAL USE OF ROENTGEN RAYSA REPORT OF THE USE OF THE CHAOUL TUBE. Arch Derm Syphilol. 1938;37(2):279–288. doi:10.1001/archderm.1938.01480080112013