[doesnotexist]

"CT scanning became widespread in the 1980's. Cancer incidence is flat to slightly decreased since then. I'm not sure their risk model matches reality. Many of these models are based on extrapolation from higher radiation exposures and there may be a fundamental issue with how they estimate risk." https://x.com/NathanRuch/status/1911803050857050502

From the paper itself: "We projected future lifetime radiation-induced cancer risk using the National Cancer Institute’s Radiation Risk Assessment Tool (RadRAT) software version 4.3.1, which utilizes risk models from the National Academy of Sciences’ Biologic Effects of Ionizing Radiation (BEIR) VII report for 11 site-specific cancers ... using a more recent follow-up of the Japanese atomic bomb survivors and pooled analyses of other medically exposed cohorts."

So I wouldn't hang my hat on the claim "that CT examinations in 2023 were projected to result in approximately 103,000 future cancers over the course of the lifetime of exposed patients."

Are CTs without risk? Of course not but quantifying that risk isn't easy with the data and models we have available. We should be glad that the authors are trying to do so but also be cautious about publicizing their estimate as an eye-catching headline. Since most who read the headline will over interpret it as an established scientific fact that meets a higher level of evidence than has actually been met.

[Barrin92]

>Cancer incidence is flat to slightly decreased since then

This is a nonsensical point because it can trivially both be true that cancer rates fall overall while CT scans cause additional cases of cancer. The comparison has to be, and that's what the original paper did, how many additional cases of cancer do you get from radiation in particular, that is to say cancer incidence could obviously be even lower all other things being equal.

[doesnotexist]

Ok sure but also the number of CT scans has been increasing exponentially (3 million CTs in 1980, 20 million in 1995, 60 million 2005[0] to 93 million in 2023[1]) so you'd need to find some opposing force that is decreasing the incidence of cancer cases exponentially per capita to keep the balance.

[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC2672242/

[1] https://jamanetwork.com/journals/jamainternalmedicine/fullar...

[BenFranklin100]

This is an example of how university press offices hype results. They are worse than street vendors in a bazaar. Researchers could do a better job of policing the press offices too.

[airstrike]

Looks like they forgot to read the relevant XKCD https://xkcd.com/radiation/

Head CT scan is towards bottom of green chart

[doesnotexist]

Love that xkcd chart. One thing it doesn't show is that different particle species of radiation have different effects on our biology at different "potencies". Gamma rays released by an atomic weapon being worse than the x-rays utilized in CT scans. A rough guide to degree of risk per species has been given a value in the form of a quality factor (Q) or a modifying factor used to derive dose equivalent from absorbed dose for purposes of radiation protection. A scale where less dangerous alpha particles are given a value of 20 and gamma, x-ray and beta a value of 1.

Here's a relevant moment from the MIT OpenCourseware Nuclear Engineering lecture about ionizing radiation damaging DNA: https://www.youtube.com/watch?v=HfRpkTG7Iow&t=30m30s

I can't recommend that course enough if you're interested in radiation physics.