80ddb deduction - gamma knife radio surgery

Main condition for Deduction u/s. 80DDB for expenses on treatment of certain chronic and protracted diseases such as Cancer, full blown AIDS, Thalassaemia, Haemophilia etc.  is:

Under the existing provisions of this section, a certificate in the prescribed form, from a neurologist, an oncologist, a urologist, a haematologist, an immunologist or such other specialist working in a Government hospital is required. 

If you have the required certificate, you can claim the deduction.