Anesthesiology

Yes, Diploma in anesthesia is a really good in terms of scope. It is a 2-year course.

Diploma in Anaesthesia gives good opportunity to practice in corporate and private hospitals. You can even take up ICU. In medical colleges as per MCI rules you can't upgrade yourself beyond Asst professor, hence you get stagnated, where as in corporate sector you can even reach senior consultant post.

Yes, you can go for anesthesia technician after 12th. On completing B.Sc. course, successful candidates will be awarded the 'Bachelor of Science' Degree. CRNA stands for Certified Registered Nurse Anesthetist.

The two fields are completely different. The only way you can decide what you like is by doing an elective and see what you like better. Honestly, I think too many people go into anesthesia because they think it's going to be low stress, and later realize it can be very stressful and become very unhappy. I'm sure radiologist, and anesthesiologist, will figure out a way to more money when the cuts come. So, be honest with yourself and do what is most interesting, rewarding, etc.