Cancer risk in 680 000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians by Mathews, JD, Forsythe, AV, Brady, Z, Butler, MW, Goergen, SK, Byrnes, GB, Giles, GG, Wallace, AB, Anderson, PR, Guiver, TA, McGale, P, Cain, TM, Dowty, JG, Bickerstaffe, AC, Darby, SC