Treatment

TREATMENT (see RADIOLOGY RADIOTHERAPY). The X-rays are used extensively in medical treatment. They are valuable in many forms of skin disease, particularly those of a chronic character. They have a favourable influence upon en largements of the lymphatic glands, of the spleen and of the thyroid gland. They give useful palliative effects in certain forms of malignant disease, and some permanent cures of cancerous conditions have been obtained by their use. In rodent ulcer, which presents features allied to cancer, there is no doubt of the efficacy of X-ray treatment for bringing about a complete cure in the majority of cases, provided that the disease has not advanced too deeply into the tissues.

The idea of using X-rays in the treatment of disease arose from recognition of the injurious effects which followed pro longed application of the rays for diagnostic purposes. Many early workers with X-rays noted the production of an inflamma tion of the skin, or a falling out of the hair over parts which had been subjected to X-rays, and Leopold Freund, of Vienna, has stated that his first attempts to utilize X-rays in treatment were made in 1896 to cure a hairy mole and were prompted by what he had read of such occurrences. A definite action of the rays upon the skin having been observed, their employment in the treatment of skin diseases followed as a natural corollary. Amongst the earliest investigators of the possible therapeutic effects of X-rays the names of Schiff, Freund, Kienbock, Holtz knecht, Sjogren and Stenbeck may be mentioned. In Great Brit ain C. R. C. Lyster, Sir Malcolm Morris, E. Dore and J. H. Sequeira were amongst the earliest investigators.

Therapeutic Dosage.

For operating successfully with an agent capable of producing decidedly harmful effects when given in large doses it is necessary to have a method of measurement, and the need for this quickly became apparent when X-rays were used for treatment. The results of X-ray photography had already shown that the tubes employed were capable of emitting radiations of varying powers of penetration, and that the tubes were by no means constant in this respect; and the question whether highly penetrating rays or rays of feeble penetration were to be preferred for therapeutic use became the subject of much discussion. It is now recognized that the choice depends upon the object of the treatment. So too the problem of measur ing the quantity of rays emitted by a tube during a given time be gan to call for a solution. In 1901 Benoist designed an apparatus

by which the quality of the rays emitted by a tube at any moment could be determined, and in 1902 Holtzknecht brought out the first quantitative device, a chromo-radiometer, which enabled the dose administered to a patient to be observed, and recorded for future guidance. Holtzknecht also drew up a scale of units by means of which the indications of his apparatus could be inter preted. The units of Holtzknecht are still used to express the dosage of X-rays, though his apparatus has been superseded. Holtzknecht's method of measurement consisted in observing the change of colour in certain pastilles when exposed to X-rays, and his apparatus consisted of a scale of tints, and a number of pastilles of a yellow tint which acquired a green colour during exposure. The composition of these was kept a secret, but analy sis revealed in them the presence of potassium sulphate combined with celluloid or gelatine. The pastilles were laid upon the sur face under treatment, and their change of colour was compared at intervals with the scale of standard tints.

Quantitative Measurement.

It was next thought that under suitable conditions the measurement of the current passing through the X-ray tube might serve as a guide to the quantity of X-rays emitted by the tube, but, although this is the case to a certain extent, the method of quantity measurement em ployed almost universally in X-ray treatment was that devised by Sabouraud and Noire, and used with signal success by them in an enormous number of cases of ringworm, in which disease measurement of dose is of the most critical importance, for the following reason. The cure of ringworm by X-rays requires that all the hair of the affected region shall be caused to fall out, but, nevertheless, it is necessary for obvious reasons that the hair should grow again after the disease has disappeared. Now if the dose of X-rays be insufficient the hair does not come out and no cure results, while if the dose be too great the hair comes out but does not grow again ; and the margin of safety is quite a narrow one. The method of Sabouraud and Noire which proved itself reliable for such critical measurements of dosage as are required for ringworm treatment, has to-day the universal acceptance of all X-ray workers for other forms of superficial X-ray treatment, although the use of their pastilles has certain disadvantages, notably that they react ill to highly penetrating or "hard" rays.