1. Department of Medical Physics; Freeman Hospital, Newcastle upon Tyne; United Kingdom
2. Department Otolaryngology-Head and Neck Surgery; Freeman Hospital, Newcastle upon Tyne; United Kingdom
3. School of Medicine, Pharmacy and Health; Durham University; Durham United Kingdom
4. Endoscopy Unit; Royal Victoria Infirmary, Newcastle upon Tyne; United Kingdom
5. Northern Oesophago-Gastric Cancer Unit; Royal Victoria Infirmary, Newcastle upon Tyne; United Kingdom
6. Department of Communication Science and Disorders; University of Pittsburgh; Pittsburgh Pennsylvania U.S.A
7. Institute of Health and Society, Newcastle University, Newcastle Upon Tyne; United Kingdom