De or het startdosering?

The correct Dutch article is:

de startdosering

Rule Words ending in -ing: almost always de. See the rule

How to use startdosering

the startdoseringde startdosering
this startdoseringdeze startdosering
that startdoseringdie startdosering
our startdoseringonze startdosering
your startdoseringjouw startdosering
every startdoseringelke startdosering
which startdosering?welke startdosering?
a big startdosering / the big startdoseringeen grote startdosering, de grote startdosering