Patient guide − Brief background and introduction to Barrett’ s oesophagus and high grade dysplasia − What photodynamic therapy is − Patients should inform their doctor before they start treatment if they have severe hepatic disease. − That PhotoBarr o Remains in your body for 60-90 days after receiving the injection o Is activated by visible light o There is an increased risk of photosensitivity (sensitivity to light) o Exposed skin will become red and cause discomfort in most cases but severe cases of photosensitivity are possible o Commercially available sun blocks are not effective in preventing sensitivity due to light − Photosensitivity can only be prevented by avoiding exposure to the sun for 90 days after receiving the PhotoBarr injection − It is important that patients tell their doctor if they get exposed to sunlight after receiving treatment with PhotoBarr. − There are a number of potential side effects that patients should be aware of.