Inclusion Criteria:

- All patients will have biopsy proven Barrett's esophagus with evidence of specialized
intestinal epithelium and dysplasia (either high grade dysplasia or low grade
dysplasia) on histology.

- Patients must have endoscopically visible segments of Barrett's esophagus of greater
than 1 centimeter in length.

- All patients must be eligible for longterm follow-up as well as tolerate endoscopy,
biopsy, and cytology.

- Patients must be willing to travel to Rochester, Minnesota for follow-up

- Patients must have a friend or relative accompany them on visits since sedatives will
render them unable to operate a motor vehicle

- If patients are on anticoagulation, they must be able to tolerate reversal of
anticoagulation for study biopsies and therapy

- All patients must be able to tolerate proton pump inhibitor therapy. Esomeprazole
will be provided but can be changed to another proton pump inhibitor if the patient
is intolerant.

- All patients who have histological or cytological evidence of high grade dysplasia
will be seen by an experienced thoracic surgeon for consideration of esophagectomy.

Exclusion Criteria:

- Patients who are unable to follow light avoidance instructions

- Patients with a history of prior esophageal surgery or successful fundoplication

- Patients who had prior photodynamic therapy

- Patients with pre-existing strictures in their esophagus

- Patients who have known allergies to porphyrin compounds

- Patients with a prior biopsies of Barrett's esophagus that contain carcinoma

- Patients who require continuous anti-coagulation

- Patients who are pregnant or are capable of pregnancy will be excluded from this
study unless they have been on effective birth control measures

- Lactating mothers are excluded from this study as it is unclear whether the
photosensitizer sodium porfimer can cross to the feeding infant

- Patients with underlying liver disease are excluded since their metabolism of
porphyrin based photosensitizers is uncertain. Evidence of liver disease will be an
transaminase elevation of three times normal, a bilirubin increase of twice normal,
or an alkaline phosphatase (liver fraction) elevation of twice normal.

- Patients who have underlying medical conditions that are felt to limit their survival
to less than one year.