It also seems to imply that medical tests which expose us to radiation are the cause of supposedly increasing cancer rates... which _seems_ a bit alarmist?
That would actually be a sound argument: If we assume a linear damage model for radiation exposure (which is a generally accepted model for these circumstances), then there is no safe dose. Instead, any exposure increases your lifetime risk of cancer. It is therefore not useful to talk about how medical imaging causes an individual case of cancer.
But for a larger population we can figure out what the cancer risk without medical radiation exposure would be, and what the observed probability is. We can then ascribe the difference to these medical tests. Obviously there are a number of ways to fuck up this analysis. Geological differences in the natural radiation dose shouldn't be underestimated. However, almost half of the lifetime radiation dose of a human does come from medical applications, and it would certainly be good to reduce that.
Really... fixating on the risk of cancer at all is a mistake. As other commenters have said, it's about balancing the risk with the value. Instead, we should find
a) How much radiation one might on average incur due to medical reasons
b) How many years of life that causes us to lose on average (or per capita)
c) How many years of life the average person gains due to the use of this technology.
As long as c - b > 0 (in a real way) we don't really have a problem here. We have an optimization to make. I don't see any evidence here that c - b <= 0. I also don't see any evidence that c - b > 0. Any other point seems moot.
