The CAT-Scan Invention

Home / IP Insights / The CAT-Scan Invention

A UK Patent No. 1283915 for “A Method of and Apparatus for Examination of a Body by Radiation such as X or Gamma Radiation” was awarded to British engineer Godfrey Hounsfield in 1968 for his innovative scanner and its technology. The first computed tomography (CT) scan, also known as a CAT scan, was invented by Hounsfield in 1971. The first human CT scan was made on October 1, 1971, using a scanner based on Hounsfield’s patented inventions.

Cat Scan Invention

Allan Cormack

While the CAT scan was developed by Godfrey Hounsfield, Allan Cormack, a South African physicist and mathematician, made key contributions to the theoretical foundation and implementation of the technology. Cormack’s work in the early 1960s provided the mathematical basis for the CAT scan, and he even built a prototype scanner in 1957. His work, along with Hounsfield’s, led to the invention of the first commercial CT scanner in 1971. The CT scan, often referred to as a CAT scan, was not invented in South Africa, but its development was significantly influenced by the South African physicist. At Tufts University in the United Kingdom, South African physicist Allan Cormack and British engineer Godfrey Hounsfield of EMI Laboratories created the CAT scan (computed axial tomography scan). This technique made it possible to turn X-ray data into 3D images. They were awarded the 1979 Nobel Prize in Physiology or Medicine for their accomplishment.

Dr. Robert S. Ledley

Dr. Robert S. Ledley, an American inventor and physicist, received patent #3,922,552 in November 1975 for a diagnostic x-ray system. The technology for using computers and X-rays to create three-dimensional images of the body was covered by this patent. He was best known for the first Whole-body Computerized Tomography Scanner or Automatic Computerized Transverse Axial (ACTA) scanner, which was capable of completing a scan much faster. The Museum of American History at the Smithsonian Institution currently house his first CT scanner, which he named the Automatic Computerised Transverse Axial, or ACTA, scanner. Pfizer purchased Dr. Ledley’s business, Disco, which produced scanners. Skid-resistant crutches were one of the more than 20 inventions he went on to patent during his lifetime.

Robert S. Ledley, Inventor of Whole-Body CT Scanner
Image source: https://www.nytimes.com/

Verified South African Inventions and Innovations

1940s: Wadley Loop Circuit – Invented by Dr. Trevor Wadley for stable frequency generation in radio equipment.

1950: Sasol – Founded as the world’s first commercial oil-from-coal company.

1950: Q20 Lubricant – Invented by Mr. Robertson in Pinetown; an all-purpose spray now owned by Triton-Leo Group.

1957: Flame Ionization Detector – Developed by Harley and Pretorius at the University of Pretoria.

1959: Tellurometer – The world’s first microwave electronic distance-measurement device, also by Dr. Trevor Wadley.

1960s: Helikon Vortex Process – Aerodynamic uranium enrichment developed at Pelindaba by UCOR.

1963: CT Scan – Allan MacLeod Cormack co-invented the X-ray computed tomography system (shared Nobel Prize in 1979).

1963: Dolos – Invented by Eric Merrifield and Aubrey Kruger to protect harbors from wave erosion.

1965: Amoils Cryo Pencil – Dr. Selig Percy Amoils created the world’s first surgical cryoprobe for cataracts and other uses.

1967: First Heart Transplant – Dr. Christiaan Barnard performed the world’s first successful heart transplant on 3 December in Cape Town.

1969: Pratley Putty – Invented by George Pratley, famously used on NASA’s Apollo 11 mission.

1970: Diamond Vitrectomy Cutter – Another invention by Dr. Amoils for eye surgery

1971: Computicket – World’s first computerized ticketing system, launched by Percy Tucker.

1974: Kreepy Krauly – The first automatic pool cleaner, invented by Ferdinand Chauvier.

1975: Scheffel Bogie – A rail bogie design by Dr. Herbert Scheffel improving stability on narrow-gauge tracks.

1978: Narrow-Gauge Speed Record – SA’s Class 6E1 train unit E1525 set a world record of 245 km/h.

1980: Casspir – Armored mine-resistant vehicle developed for military and police use.

1984: Denel Rooivalk – Development of South Africa’s indigenous attack helicopter began.

1989: FlightScope – Henri Johnson developed this radar-based golf ball tracking technology.

1991: APS Therapy Device – Invented by Gervan Lubbe, used to treat chronic pain and sports injuries.

1992: Speed Gun & Speedball – Developed by Henri Johnson to measure speed and trajectory in sports like cricket and golf.

1995: Thawte Consulting – Founded by Mark Shuttleworth, a major digital certificate authority (later acquired by VeriSign).

1996: Vodago Prepaid Mobile Phones – Vodacom launched the world’s first prepaid mobile platform with real-time billing.

1997: CyberTracker – Developed for conservation; enables illiterate trackers to record environmental data digitally.

1997: Hippo Water Roller – A barrel-shaped container allowing efficient water transport, designed for rural communities.

1998: Blaster Car Flamethrower – Charl Fourie designed this anti-hijacking device.

1999: Smartlock Safety Syringe – Widely credited with reducing needle reuse and HIV infections in SA (attributed locally but with global development context).

2001: Cobb Grill – A safe, portable, fuel-efficient charcoal stove developed by Ken Hall, featured in TIME’s Best Inventions.

2001: Oil-Can Guitar – Invented by Graeme Wells, blending traditional guitar function with recycled materials.

2004: Ubuntu OS – First released by Mark Shuttleworth, this Linux-based operating system has global impact.

2005: Cenocell “Cementless Concrete” – Invented by Prof. Mulalo Doyoyo; eco-friendly building material.

2008: Freeplay Fetal Heart Monitor – A hand-cranked device for use in low-resource areas.

2013: Amoriguard Paint – Created by Prof. Mulalo Doyoyo using recycled industrial waste.

2013: Digital Laser – Invented by Dr. Sandile Ngcobo; enables lasers to be digitally shaped on demand (Nature Communications).

2019: 3D-Printed Ear Bone Transplant – Prof. Mashudu Tshifularo performed the first such surgery at Steve Biko Academic Hospital.

IP Insights

Innovation Station