Hi Patricia, As you probably know, the verb vado (andare) can be followed by 3 prepositions: a, in, da. In your exemple the preposition is DA becouse dottore is a person. The rule is that when "andare" is going to a person, the preposition is always DA (with or without article, depending on the case) Esempi: vado da Mario, vado da Giuseppe, vado da un mio amico, vado dal parrucchiere, vado da mamma, vado da mio zio, vado da tua sorella... ok? :)

Thank you Professora Annarita! That makes perfect sense.

Ciao Patricia! We use the preposition DA + article when the place you are going to is expressed by a person ("dottore"). Buono studio, Annarita