Physics Bucharest 2017

Reason 1) before 1951 many beams to reduce skin dose

1895: discovery X-rays 1913: 140 kV, Coolidge: vacuum tube, heated kathode

1921: 200 kV 1925: 300 kV 1951: first cobalt treatment unit 1952: first clinical linear accelerator (Increase Energy → reduce skin dose) orthovoltage

100 120

Dose

0 20 40 60 80

> 1913 > 1951 > 1952

early days

Depth [cm]

0

5

10

15

20

25