focus & concentrate
be focused on
... I have been focused in the technical vocabulary of medical texts, ...
The use of passive doesn't feel quite right. The preposition seems improbable. My BNC searches revealed the following numbers of hits.
14 hits: in starts prepositional phrases functioning as adverbials generally, rather than being the object of the preposition.
be focussed on is much more promising with 345 hits.
But bear in mind that focus (vb) occurs 5546 times, without be 5027 times of which 2893 are followed by on.
This almost makes the passive use of focus an abberation.
The verb concentrate reveals the same pattern.
concentrate 6954
be concentrate (ed/ing) 948
be concentrated 655
be concentrated on 336
[not be] concentrate on 3624, the CQL for which is [lemma != "be"][lemma = "concentrate" & tag = "V.."][word = "on"]