Science Museum. Brought to Life: Exploring the History of Medicine.

Body images dominated the way disease was diagnosed during the 20th century. X‑rays were discovered by Wilhelm Roentgen in 1895 and had an immediate impact. Other body imaging techniques such as MRI, PET and ultrasound were developed over the century. ECG and other machines that visually recorded body function became central to hospital medicine.

X‑rays transform diagnosis and treatment

Copy of photograph of a radiograph of a hand, covered with glass, taken by Roentgen, Wurzburg, Germany, 1895.

Credits:Science Museum, London

X‑ray technology saw inside living patients’ bodies without the need to cut them open. X‑rays are a form of . They cannot penetrate denser body parts, such as bones, creating shadows on special photographic paper. X‑ray images proved popular, and were even used to size shoes. Doctors used them to locate broken bones or items lodged in the body, such as bullets. X‑rays also offered new therapies, known as radiation therapy. This was found to be effective at treating cancer and other conditions such as ringworm.

Harmful rays

X‑ray technology harmed as well as healed. By the late 1920s, large doses of X‑ray radiation were found to seriously damage the body. By the 1930s protective measures and equipment were developed to reduce the radiation dose from machines. This made them safer for practitioners and patients. In the 1950s Alice Stewart’s work linked foetal X‑rays and childhood cancer.

Radiologist studying CT brain scans.

Credits:Wellcome Photo Library, Wellcome Images

X‑ray technology advances

New techniques and machines increased doctors’ abilities to see details and movement inside the body. From the 1920s, contrast media depicted organs such as the stomach. In the 1930s multiple X‑ray images of sections of the body were overlaid in a popular technique called tomography. Forty years later Godfrey Hounsfield combined this technique with computer power to create the first CT scanner. This machine produced the first detailed images of a living brain.

The rise of scanners during the 1970s

Computers made other body imaging machines possible. ‘Scanning’ described machines that took readings of the body and used computers to turn the data into visual images. MRI was developed in 1973. This made images using computers to record tiny signals from atoms inside the body. PET was developed in 1975. PET machines tracked trace amounts of radioactive materials injected into the blood. This helped doctors visualise brain and bodily functions.

Using machines to trace body function

EEG trace.

Credits:Miles Kelly Art Library, Wellcome Images

ECG and EEG produced their findings as graphical ‘traces’. These visual patterns helped doctors quickly understand what was happening to body function and react accordingly. Medical students learned classic ‘trace’ patterns to recognise medical problems. Visual monitoring machines were critical to intensive-care medicine by the late 1900s.

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