The invention relates to a rotational position determination apparatus (15) for determining an entry rotational position, which defines a rotational position of an insertion device like a stent at an entry site (5), such that a navigation of the insertion device from the entry site to a target site (6) along an inner path (8) results in a rotational position of the insertion device at the target site being equal to a desired target rotational position based on a representation of the inner path and the desired target rotational position. If the insertion device is arranged in the determined entry rotational position at the entry site and then navigated to the target site, it is therefore not necessary to rotate the insertion device at the target site, i.e. it is not necessary to use a technically complex interventional device for rotating the insertion device at the target site.
