Background and aims-Photodynamic therapy (PDT) is a treatment in which cell damage is achieved by the action of light on a photosensitising agent. We have assessed the potential use of PDT in the ablation of Barrett's oesophagus. Methods-Thirty six patients with dysplastic Barrett's oesophagus receiving acid suppression medication with omeprazole were randomised to receive oral 5-aminolaevulinic acid (ALA) 30 mg/kg or placebo, followed four hours later by laser endoscopy. Follow up endoscopy was performed at one, six, 12, and 24 months. Results-Of 18 patients in the ALA group, a response was seen in 16 (median decrease in area in the treated region 30%; range 0-60%). In the placebo group, a decrease in area of 10% was observed in two patients with no change in 16 (median 0%; range 0-10%; treatment v placebo, p<0.001). No dysplasia was seen in the columnar epithelium within the treatment area of any patient in the PDT group. However, in the placebo group, persistent low grade dysplasia was found in 12 patients (p<0.001). There were no short or long term major side eVects. The eVects of treatment were maintained for up to 24 months. Conclusions-This is the first randomised controlled trial of PDT for Barrett's oesophagus. It demonstrates that ALA induced PDT can provide safe and eVective ablation of low grade dysplastic epithelium. (Gut 2000;47:612-617)
Photodynamic therapy (PDT) is a treatment in which cell damage is achieved by the action of light on a photosensitizer. The aim of this study was to assess the value of PDT in the treatment of Barrett's esophagus with low-grade dysplasia (LGD). Forty patients with dysplastic Barrett's esophagus were given aminolevulinic acid (ALA) 30 mg/kg orally followed 4 h later by laser endoscopy. Follow-up endoscopy and biopsies were performed at 1, 6 and 12 months. A macroscopic response was seen in 33 out of 40 patients, with a median decrease in columnar epithelial area of 30% (range 0-90%). Post-treatment biopsies showed no dysplasia in 39 out of 40 patients, with LGD remaining in one case. This was maintained at 6 and 12 months. There were no significant side-effects. This study demonstrates that ALA-induced PDT provides safe and effective ablation therapy for Barrett's esophagus and is particularly useful against dysplasia.
Preliminary observations of a pulsed Ho:YAG laser on human uterine tissue in-vitro are presented. The tissue effect on the uterine myometrium was demonstrated using fresh uteri which had been subjected to laser energy. The laser crater and surrounding zone of thermal necrosis (ZTN) was quantified. Measurements demonstrated a consistent narrow ZTN (0.8-1.8 mm) irrespective of power or pulse frequency used. The percentage forward transmission of laser energy through 1 mm of myometrium was investigated using a pyroelectric detector and found to be 0.41%. Finally, a visible and measureable photoacoustic component to the Ho:YAG laser was demonstrated using a water bath and needle hydrophone.
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