The aim of the study is to evaluate whether open-face masks improve patient comfort/preference whilst maintaining immobilization performance as known for closed masks in patients undergoing whole or partial cranial radiotherapy.

Upon randomization, patients will be begin treatment either with an open-face mask (A) or closed mask (B). Two individual immobilization masks - the open-face and closed masks - will be fabricated for every single patient. During the 1st half of treatment the randomly assigned mask will be used followed by using another mask for the 2nd half of treatment. Discomfort/pain/anxiety and mask preference will be scored during treatment with a questionnaire.

Inclusion Criteria:

• Written informed consent according to Swiss law and International Council for Harmonization (ICH)/Good Clinical Practice (GCP) regulations before any trial specific procedures;
• Indication for cranial radiotherapy irrespective of tumor type;
• Age: ≥ 18 years old;
• Karnofsky performance status ≥70;
• Patients who are willing and able to comply with scheduled visits, treatment, and other trial procedures.

Exclusion Criteria:

• Cranial radiotherapy in less than 10 fractions;
• Prior brain irradiation;
• Inability to complete magnetic resonance imaging (MRI) procedure due to claustrophobic anxiety;
• Women who are pregnant or breast feeding;
• Intention to become pregnant during the course of the trial;
• Lack of safe contraception;
• Known or suspected non-compliance, drug or alcohol abuse