Population of the world  7 billion

Assuming average life span of 70 with equal distribution

Break down cohorts

0 to 10 – well taken care of, may fall sick twice a year/doesn’t require X rays often, assume 10% of cases require X rays, each X ray has 2 scans on average

10 to 20 – active life style, may fall sick once a year + may get injured/doesn’t require X rays often, assume 20% of cases require X rays, each x ray has 2 scans on average

20 to 40 – immunity is slowly reducing, takes good care of self, less active life style so may not be as prone to injuries , 20% of cases requires x Rays , each X ray has 3 scans on average

40 to 60 – immunity is reduced, more prone to falling sick, doctors may recommend preventive x rays, 50% of cases require x rays with 3 scans each

60+ – immunity is greatly reduced preventive x rays a must, 70% of cases require x rays , with 3 scans each

totally up the above as = population x % of cases requiring x-rays x occurance rate x scans you get 6.9 billion scans BUT that’s assuming everyone has access and can afford to get x ray , assumign 80% have access and only 50% can afford to pay that becomes 2.8 billion X rays