Easy answers are wrong :)
"Maybe they could employ some more staff?"
What a great idea. It's not like there is a shortage of radiologists. Certainly not worldwide, and definitely not in the UK....
Here's the 2017 report:
Shortfall is roughly a 1000 consultant level positions.
The money spent on outsourcing imaging would cover ~1300 consultants. So the budget exists, but no staff.
~10% of clinical radiologist posts are not currently filled. 70% of them haven't been filled for more than a year.
Of the clinical radiologist's trained in the UK each year (~300), 83% join the NHS.
So it seems that there is money to pay for them, a training program that the majority of graduates enter the NHS and yet we're still short. Vacancies are going unfilled for years. So "hire more bodies" doesn't work when there aren't any more.
Overseas recruitment has dried up too. There's plenty of demand all over the world, and the UK is not currently a great place to relocate too.
Note, this is nothing new. This has been coming for at least a couple of decades. Workload increase of 20-30% pa, hiring increase of 2-4% pa.