Rarely is the whole rainbow used in radiology (eg CT perfusion, DTI) and one can switch the color scales to the part of the spectrum you're not blind to.
Yep. Radiological images come in black and white. Images are colorized afterwards for presentation, but clinical scans are generally not colorized. In internal med, there is usually a way to identify things other than color. There are lots of colorblind docs. Don't worry about it.