X-Ray Day

What the day is

X-Ray Day is observed on November 8, marking Wilhelm Rontgen's discovery in 1895.

Origin and background

Rontgen was experimenting with a covered cathode ray tube in a darkened laboratory when he noticed a screen across the room fluorescing. Something was passing through the covering and through the air. Over the following weeks he established that the rays traveled in straight lines, were not deflected by magnets, and passed through many materials in inverse proportion to their density.

He called them X-rays because X stood for unknown, and the placeholder name stuck permanently.

The most famous early image is of his wife's hand, showing the bones and her wedding ring, and her reported reaction on seeing it was that she had seen her own death. The finding spread with remarkable speed: within months, physicians across Europe and America were using X-rays to locate fractures and bullets, an adoption rate almost unheard of in medicine.

The dangers took longer to understand. Early operators calibrated machines by exposing their own hands, and many experimenters and technicians developed burns, lost fingers and died of cancers. Shoe-fitting fluoroscopes stood in shops well into the twentieth century, giving children repeated doses for entertainment.

Rontgen refused to patent his discovery, holding that it belonged to humanity, and he received the first Nobel Prize in Physics in 1901. He donated the prize money to his university.

How to take part

• Look up the 1895 image of the hand. It is still striking.
• Ask about dose if you are offered imaging, and about whether ultrasound or MRI would answer the same question without radiation.
• Keep a record of your own imaging history, which few people do and which spares repeat scans.
• Read about the radium and fluoroscope era as a case study in adopting a technology before understanding it.
• Thank a radiographer. The people operating the machines are rarely the ones anyone remembers.