A chance discovery…

It’s surprising isn’t it how many of our discoveries in the past had been made by accident.

Alexander Fleming returned from a holiday to his laboratory to discover a strange fungus on a culture he left there. That fungus had killed off all the surrounding bacteria in the culture. This led to the discovery of penicillin.

After walking in front of a magnetron, Percy Spencer in 1945 notice that a bar of chocolate in his pocket had melted. After a few more experiments he successfully invented the first microwave oven.

John Pemberton was a pharmacist hoping to cure headaches by mixing two main ingredients, coca leaves and cola nuts. His lab assistant accidentally mixed the two with carbonated water and Coca-Cola was born.

William Roentgen

The discovery of x-rays was also an accidental one. The discovery of the x-ray is mainly attributed to Wilhelm Roentgen, Professor of Physics in Worzburg, Bavaria in 1895. In his laboratory he had been working with a device known as a Crookes tube.

Crookes tube_opt

Crookes tube

A Crookes tube is like a high powered light bulb with a cathode at one end and an anode at the other with a high voltage power supply attached to them both. There is a partial vacuum inside the tube. When a high voltage is applied between the electrodes, electrons are projected in straight lines from the cathode. These were initially called cathode rays, and as they are negatively charged particles they were later renamed to electrons. This was a high voltage device, emitting hundreds of thousands of volts from the cathode. When connected the tube would give off a blueish light, a result of the emission of the cathode rays.

The scientists of the 19th century felt that this tube was also emitting other types of rays in addition to the cathode rays. This is what Professor Roentgen was investigating in his lab. On November 8, 1895 he had his Crookes tube set up as you can see in the diagram above. Once it was connected it glowed in the usual way. Because he was interested in rays other than the usual ones he didn’t want the blueish light interfering with his investigation so he covered up the Crookes tube with a black box to exclude this from his experiment.

Having done so he turned off the light in the room and turned on the power to the Crookes tube. It was at this point that he noticed a faint glow from a piece of paper sitting about 8 feet away on another table. This piece of paper had been impregnated with a phospho fluorescent material and it was now giving off a green glow. In order to check that it was the cathode ray tube that was causing this piece of paper to glow, he turned it off at which point the glow from the paper also disappeared. Then when the power was restored to the cathode ray tube the paper began to glow once more.

In order to confirm what he believed he was seeing he bought the paper closer to the Crookes tube and started to put objects between the paper and the tube. This created a shadow on the paper. He noted at the same time that a metallic object for example would create a dark shadow than perhaps a sheet of paper would which created almost no shadow at all.

At one point whilst holding various objects in front of the tube he also believed that he could see the bones in his hand, although he was not sure at the time whether this was just a trick of the light.

He went on to continue his investigations of this new phenomenon, giving these new rays the letter X which denotes the unknown. Hence they became known as x-rays.

Roentgens wifes hand_opt

Roentgens wifes hand

It is believed that he then started to capture some of the very earliest x-ray images, one of the first being an x-ray of his wife’s hand.

Shortly after this he went on to give his first presentation of his discovery at a scientific conference. He brought up the scientist Albert von Kolliker, sat in next to the Crookes tube and took a radiograph of his hand.

The scientists of the day were suitably impressed, hailing this as one of the discoveries of the century and going so far as wanting to name the new rays after the discoverer, Roentgen.

Edison and Dally

By the spring of 1896, Thomas Edison had created a handheld fluoroscopic device which many doctors were using. The glass tubes being used to generate the X-rays were mounted with no form of protection and beams would go off in all directions. In the early x-rays the cathode ray tube would be switched on, the Dr would place the handheld fluoroscope over his eyes, and the patient’s area of interest would be placed in between. This method of using the x-rays resulted in tissues and bones of the users being affected.

Clarence Dally worked with Edison in the development of the X-ray machines. During his work he would regularly hold his hand between the fluoroscope and the x-ray tubes exposing himself to radiation for hours on end. As time went on he began to show signs of radiation poisoning. His hair began to fall out followed by his eyebrows and eyelashes. His left hand became swollen and painful, but undeterred he simply went on to use his right hand instead. Later, having already had skin grafted from his leg to his left hand several times he ultimately agreed to have his left arm amputated just below the shoulder. Unfortunately a little later is right hand began to develop the same problems, and he had to have forefingers removed. This meant he could no longer work. It was at this point that Edison put an end to his experiments with x-rays.


Elizabeth Fleischman helped her physician brother-in-law to use an x-ray device in his practice and did so regularly. She also first showed signs of excessive x-ray use in her hands. This started mainly with ulceration, chiefly to the tissues over the middle phalanges and the middle joints. She then went on to develop lumps under her arm which indicated a lymph node involvement. The arm and scapula and clavicle were removed, she initially did well but eventually she succumbed to metastases in the pleura and lungs. She died in August 1905.

William Coolidge devised a hot cathode ray device which was housed in a metal container with one aperture for a focused beam. This made the device somewhat safer to use. He also went on to invent the first rotating anode X-ray tube. This reduced the amount of wear on the anode, prolonging its life and also ensuring greater accuracy of the X-rays.

However it was still not fully realised for many years how dangerous the effects of x-rays could be on the human body with prolonged exposure. X-ray machines were even used in stores to ensure that shoes fitted correctly. The customer would put their feet in the x-ray machine and there were three viewing ports so that the bones could be seen within the shoes.

Dr Eric Strong- Interpreting Chest X Rays

Radiology Masterclass- Chest X Ray


Hammadshams YouTube




Possibly the book I most highly recommend for nurses to use as their pocket guide. Phil Jevon is a practitioner in Walsall and has produced an easily read, pocket sized tool. You can click on the picture above  to purchase this excellent book.
Talley and O'Conner
Slightly less 'weighty' than Macleods but still with lots of useful detail and information. The latest copies also have a CD with good, well narrated examples of clinical examination.
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