Other important improvements, meanwhile, were being introduced by the German specialists, during the World War and later, among which was the just mentioned method of giving large tissue-destroying doses, requiring from ten to 15 hours; to this was added careful filtration of the rays, and the invention of the ionto—a quantimeter for exact measurements. A number of malignant diseases is reported to have yielded to this new system of massive doses under higher voltage. But Professor Duane has stated that neither X-rays nor the gamma rays of radium should be considered as a permanent cure for cancer.
Until recently the tubes in which X-rays are produced have always been made of glass. The latest discovery is a tube made of fused silica, or vitreosil. Vitreosil permits the passage of the short rays, will stand a much higher temperature than glass, and is much stronger. This means more continuous service from X-rays.
According to Dr. Francis C. Wood, director of the Crocker Institute of Cancer Research of Columbia University, a marked advance in the treatment of cancer has been made possible by a new type of X-ray tube, the invention of Dr. C. T. Ulrey, of the Westinghouse Company. The new tube has a higher emissive power—in other words, it is as if the candle-power of an ordinary lamp were increased six-fold. It is besides designed for use with higher voltages than have previously been practical in Roentgenology. The result is to reduce the necessary exposure from two or three hours per patient to 20 minutes, and to increase the life of the tubes. Incidentally, the new tube gives a greater proportion of the type of rays that cure certain forms of cancer, and less of the sort that attack healthy tissue.
A revolutionary discovery by Dr. Jacques Forestier, of Aix-les-Bains, France, for which a gold medal was awarded him in 1925 by the French Academy, has made possible a method of exact diagnosis by X-rays heretofore deemed by many workers impossible of attainment.
As is well known, it is not difficult to make an X-ray picture of the bones of the body. They are so much denser than the soft parts of the body that, even with the ordinary photographic plate, it has been possible to photograph them fairly well. By pumping the stomach full of gas or air—which are highly transparent to the X-rays—and then applying the X-ray, it has sometimes been possible to locate the beginnings of cancer of the stomach, and the place of malignant growth.
Another method in common use is to give the patient about a pint of some substance opaque to X-rays, such as bismuth carbonate, thus making it possible to record the passage of the mixture, the outline of the stomach and the intestines thus being made visible. In this way ulcers of the stomach have been frequently located.
Bismuth and similar substances could not be injected into the brain or spinal cord, on account of their poisonous effect on the highly sensitive cells of these regions. Now, thanks to the method discovered by Dr. Forestier, the cavities of the brain and spine can be safely explored, as well as the network of bronchial tubes in the lung—the so-called “bronchial tree.”
In an interview with Mr. David Dietz, Dr. Forestier said (in part):
“I make use of a French oil called lipiodol. It is a chemical compound composed of poppyseed oil and iodine. The chemical previously had been used as a treatment for certain diseases, such as goiter. But no one had ever thought of using it in X-ray work.
“I noticed that where patients had been treated with lipiodol opaque spots appeared when X-ray pictures were made of the treated parts. It occurred to me, therefore, that lipiodol could be used as a means of making photographs.