We fitted one in a chest cancer depatment, it had been spec'd to have a huge supply cable, 4 core 240mm iirc, yet the power requirements of the unit were quite small. Anyway, in the large control / input panel, there was a transformer that weighed around 100kg. I had nothing to do with the internal wiring, but presumed it was acting like an isolating transformer, to give separation from the mains supply.

Some designs can be very thirsty when actually scanning - consider page 7 of this manual from Siemens showing 120kW per source - but of course most of the time it is not illuminating the patient at all, during set up and positioning, and if even it is, not always at absolute full power - so other data suggests that only about 20kW of cooling is needed. The risk of a long thin supply is if supply droops too far during those very occasional calls for full steam ahead....
( I am aware of versions that have been repackaged for field hospitals, where reliable power supply is more of an issue, and these need very careful management to avoid electrical problems..)

Mike

Yes, a CT scanner was deployed to Camp Bastion.

That second link mentions average power of 20 kW, but averaged over what? The max consumption is 125/140 kVA.

It's a wonder that the hospital lights don't dim when they are scanning!

Averaged over the scan - which is a series of 'slices' where the source at is rotated about the patient and data acquired, and then the patient is moved in or out of the scanner fractionally and another slice of the scan is taken, In the meantime some very clever software is used to stretch and scale the 'images' to form the view that is presented to the radiographer. between doing this, the source is turned right down or off. It is possible in some designs to have the patient moving steadily and a helical scan, then the load is more constant, but the image stitching problem is harder.

It would require very large capacitors to store enough energy as DC to store enough energy for a whole scan and smooth this out, so it s easier to put a bursty load across the mains,  and to live with the need for a dedicated sub-main that looks like it is being under-run,  on average.

Compared to those hospitals that have a cyclotron in the basement for the preparation of nuclear medicines, it is still not a huge load -those can be in the low hundreds of kW, but tend to be run at full power for signficant  periods.

Mike,

For some reason, Mike's posting reminded me that in the early days one talked of Hounsfield units rather than pixels.

I am bound to wonder where all this energy ends up. CT scanner rooms are not noticeably hot.

I also recall the X-ray tube which we had at school. IIRC it was Hull Royal Infirmary's original one. By all accounts, it had been fired up until a few years previously so that boys could make images of their hands using home-made plates thus combining the disciplines of physics and chemistry in one lesson.

For some reason, Mike's posting reminded me that in the early days one talked of Hounsfield units rather than pixels.

I am bound to wonder where all this energy ends up. CT scanner rooms are not noticeably hot.

I also recall the X-ray tube which we had at school. IIRC it was Hull Royal Infirmary's original one. By all accounts, it had been fired up until a few years previously so that boys could make images of their hands using home-made plates thus combining the disciplines of physics and chemistry in one lesson.

I remember the excitement of being allowed to X-ray my own feet in shoe shops when I was a kid.

en.m.wikipedia.org/.../Shoe-fitting_fluoroscope