IEC 61217:1996

Applies to equipment and data related to the process of
teleradiotherapy, including patient image data used in relation
with radiotherapy treatment planning systems, radiotherapy
simulators, isocentric gamma beam therapy equipment, isocentric
medical electron accelerators, and non-isocentric equipment when
relevant.

The object of this standard is to define a consistent set of
coordinate systems for use throughout the process of
teleradiotherapy, to define the marking of scales (where provided),
to define the movements of equipment used in this process, and to
facilitate computer control when used.