Old game from Czech Republic

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This is position from one of my old games (played in 2008). I was white and I got very nice position from Alekhin´s defence. I have to admit that my preparation succeed very well, however ,   my young oponent put a very good resistant. In the position on the diagram I can play 25.Nd6 and win an exchange. Is it the best option? Is there something better for White? 
It is quite obvious that White can win control over diagonal with:
25. Rd2  and only move is 25...Qa3. Now White checks with 26.Qd4+ and Black plays 26...Kh6 ( this is by far the safest square for Black´s king). Is there something for White? If it is Black´s move he would play something like 27...Bd5 or 27...Bf5 and in good moment Qc5 with exchange of queens. Solution will be published tomorow.