Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
treatment [ˈtriːtmənt] n (attention, handling) обраще́ние; (MED) лече́ние
to have treatment for sth проходи́ть*(пройти́*perf) курс лече́ния от чего́-н
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.