Table 1a.

Key discoveries and technological developments in diagnostic radiography

Year	Discoveries and technological developments
1895	Röentgen: x-rays
1896	Edison: calcium tungstate
1904	Self-regulated gas tubes
1908	Snook: generator provides selectable kV and mA
1913	Coolidge: first successful roentgen-ray tube
1914–16	Patterson: fluoroscopic screen; Trendelenburg: red goggles to facilitate use of fluoroscopy
1917	Potter-Bucky diaphragm: reduce scatter by secondary radiation
1917	Kodak: Double emulsion acetate film
1924	Film changer for serial x-rays
1928	Siemans: Three-phase generators
1929	Bouwers (at Philips): rotating anode x-ray tube, shielding provided by tube housing integrated in tube assembly
1934	Ziedes des Plantes described film subtraction to aid in visualization of small blood vessels
1941	First automatic film processor
1942	X-ray phototimers
1947	Xeroradiography
1948	Coltman: Image intensifier tube for fluoroscopy
1960	Dupont: Polyester film base replaces acetate
1964	Kodak: 90 second Xomat processor
1964–68	Cormack and Hounsfield: CT scanner
1973	Buchanan: Rare earth screen phosphors
1979	Fuji Photo Film: Digital subtraction angiography
1982	Ultrafast CT scanner
1984	Computed radiography systems
1989	Heiken et al: Slip-ring helical CT volume imaging
1993	Solid state digital x-ray detectors

Sources: Siebert JA. Health Phys 1995;69:695–720. Hall E. Radiobiology for the Radiologist, Fifth Edition. Philadelphia: Lippincott Williams & Wilkins, 2000, pp 1–4.