title: Short-Distance Low-Voltage X-Ray Therapy: (Section of Radiology).
abstract: Short distance X-ray therapy is characterized by the application of a very high dose to the diseased area only; the surrounding and underlying healthy tissue, being spared irradiation, is therefore able to assist the process of repair. Distribution of the dose is obtained by providing for a steep energy gradient within the tissue and by using metal applicators with fields of entry from 9 to 25 sq. cm. The short focal distance required is made possible by a monopolar X-ray tube of unusual design run at a constant potential of 60 kv., the total filtration amounting to 0.2 mm. of copper.Doses of 300 to 500 "r" are administered every day for from two to four minutes. The total dose applied to the patient during two to four weeks is from 5,000 to 10,000 "r". From these data it is apparent that the new X-ray therapy has many features in common with ordinary radium therapy.Up to the end of 1935 231 cases had been treated by this method, the time of observation extending up to four years. The statistics include cases of cancer of the lips, the oral cavity, the eyelids, forehead, nose and ear, and on the surface of the trunk and limbs.The possibilities of the method are, however, by no means restricted to tumours located on, or near, the surface of the body or in body cavities. Recently its scope has been extended to the treatment of deep-seated tumours, notably tumours of the rectum, made accessible by surgical operation. The results obtained in these cases are very encouraging. For instance, the first patient treated by this method two years ago has enjoyed perfect health and is pursuing his normal occupation.In the case of tumours of large size or with many metastases, or having previously undergone intensive X-ray or radium treatment, the method is contra-indicated.