X-RAY INVENTION

Evening Star, Issue 22973, 2 June 1938, Page 13

X-RAY INVENTION

"SEES (SOUND CORNERS" What is probably one of the most important developments in X-rays in recent years was shown to specialists in London recently, says the ‘ Sunday Express.’ It is a discovery which' makes possible X-ray photographs which could never be taken before. These photographs show parts of the body which have always been concealed or partially concealed by overlying structures. The instrument is called a tomograph, and this is the fascinating story of how it works:— When an X-ray photograph is taken it shows the internal construction of the body, but it shows all the successive layers superimposed one on the other, and it is often impossible to see each part clearly. It is easy to see all the structures in an X-ray of the hand, for instance, but sometimes very difficult to see clearly all the structures in an X-ray of the head and the lungs, and especially in diseased lungs. That has always been the radiologist’s problem. And that problem the tomograph solves. In the tomograph the X-ray tube is above the patient, the rays passing right through his body on to the photographic plate underneath him. Instead of being stationary, the X-ray beam moves. It moves in just the way it could move if it were on the edge of a big wheel, of which the hub was exactly in the part of the body the specialist wants to see. The plate under the patient also moves, but in the opposite direction. Suppose an X-ray exposure lasts ssec. The ray will be passing through the centre of the imaginary wheel for the whole ssec, because whatever the position of a wheel in motion its centre is stationary. That means that the point selected by the specialist will bo photographed. But all the other parts of the body around this point are not the centre of the wheel. The X-ray only passes through them for a fraction of the time, one after another. The result is exactly the same as when a photographer is giving a time exposure of a street in the evening.

The street comes out, but passers-by who just flit in front of the camera for a second do not come out. So in the tomograph, only the part at the stationary point of the moving ray comes out and the other parts ofl the body just “ flit by.” On the plate they are just a blur. The tomograph, in short, enables the X-ray to “ see round the comers.’’ The X-ray tube can be focused on any given point in the body, and intervene ing objects are faded out. Its possibilities for the good of mankind are immense. It is possible to photograph the centre of the skull , without the other parts. It shows the spine clearly, while the ordinary X-ray .shows it partly obscured by the ribs. Delicate adjustments make it possible to take a picture at any “ depth ".of the body, inch by inch. It is even possible to photograph the bronchial tubes in the lungs. It will make immensely easier the diagnosis of many diseases, among them cancer of the lung, tubercular cavities in the lung, and spinal conditions A tomograph apparatus costs about £I,OOO, but attachment of the to mo- •' graph to existing apparatus costs considerably less.