The Department of Radiation Oncology at Rigshospitalet has pioneered the use of DIBH in the treatment of patients with breast cancer and mediastinal lymphoma [Korreman et al., Pedersen et al.] and is currently prospectively testing the DIBH technique in a more frail population of lung cancer patients. The department has extensive experience in the daily delivery and patient coaching of adult patients. While the experience from several centers confirms that the compliance of adult patients to DIBH is excellent, no reports exist of the applicability of DIBH to pediatric patients, especially the very young.