I appreciate you looking into the numbers to verify. The 1/1000 odds seem better, though still important.

Also, framed another way, 5% of cancer cases caused by CT scans would mean that 1 in 20 people in the cancer ward were placed there by a CT scan. Or alternatively, phasing out CT scans would prevent 1 in 20 cancer cases, with prevention being worth more than a cure for every 1 cancer patient in 20.