More than 750000 people in the UK have some form of dementia; with a rise expected over the next 25 years. With early diagnosis of cancer, more patients with dementia will attend for cancer treatment. Immobilisation masks, used to ensure accurate head and neck radiotherapy, may trigger panic in patients, even without prior mental health problems. This single case study reports on the care provided to a patient with dementia and his carer, his wife Betty, during cancer treatment. Bert was diagnosed with dementia 10 years prior to his cancer diagnosis. The use of sedation appeared to trigger confusion rather than facilitate procedures. Bert's case illustrates how an individualised contract of care could be developed to help maximise interactions, ensure ongoing consent and maintain dignity during difficult and challenging medical procedures.