Yes. After MBBS you can opt radiology,As most modalities are rendered in gray-scale,therefore there is very little applications of color.Despite Doppler ultrasound has some color,the color intrinsically is not critical, especially when one is using power doppler or spectral Doppler.In respect to nuclear medicine most of the time the colors are irrelevant.This is because diagnostically radiologists do not use the color fused series when reporting PETCT  or similar. The false color image are for the clinicals to get a sense of what is going on. Most PET reporting is done with the co-registerd functional and anatomic components side by side not overlaid and therefore color is not needed.Also the colourblind will not affect your judgement and your diagnosis power which is most important for medicine.

Along with this you can go for pediatric,geriatrics,pulmonary medicine,ENT,dermatology,Psychiatry,Pre clinical subjects(anatomy,biochemistry,physiology),Pharmacology,Community medicine,OB-Gyn(MD).