Received: 20 September 2019
Accepted: 20 November 2019
First Online: 2 December 2019
Ethics approval and consent to participate
: All data used in this study was either phantom data or anonymized before import. There was no key or other way to trace back original patient names. All the patients enrolled in this study signed informed consent.
: Not applicable.
: JH and BH are employees of Varian Medical Systems. The authors declare that they have no other competing interests.