Overholt B F, Panjehpour M, DeNovo R C, Peterson M G, Jenkins C
Thompson Cancer Survival Center, Knoxville, Tennessee 37916, USA.
Lasers Surg Med. 1996;18(3):248-52. doi: 10.1002/(SICI)1096-9101(1996)18:3<248::AID-LSM5>3.0.CO;2-S.
Photodynamic therapy is currently being used to treat various malignancies including esophageal cancer. The effect of photodynamic therapy depends upon the concentration of photosensitizing drug, light energy delivered to tissue, and the presence of oxygen in the targeted tissue. We have found that an esophageal centering balloon improves light delivery to esophageal mucosa. However, balloon pressure on esophageal mucosa could possibly reduce mucosal blood flow and oxygenation, therefore reducing the effect of photodynamic therapy. This study was conducted to investigate the effect of balloon pressure on the esophageal wall during photodynamic therapy in the canine esophageal model.
STUDY DESIGN/MATERIALS AND METHODS: Studies were performed in the canine esophagus of ten animals to investigate whether increasing the size of the centering balloon, and hence the pressure on esophageal mucosa, would alter the tissue effect of PDT. Porfimer sodium 4 mg/Kg was administered and 630 nm light was delivered via a 1 cm diffuser located in the center of a 360 degrees 2 cm windowed balloon. Mucosal light measurements were made to ascertain equivalent mucosal light dosing of approximately 25 J/cm2. Endoscopic and necropsy findings obtained following photodynamic therapy with 25 mm, 33 mm, and 35 mm balloons were compared.
In larger dogs (groups A and B), increasing the size of the esophageal centering balloon from a 25-33 mm size did not result in an overly tight fit nor was the increase associated with significant change in the PDT effect. In contrast, increasing the balloon size to 35 mm in smaller dogs (group C) resulted in a tight fit of the balloon in the esophagus and in significant reduction in the PDT effect on mucosal damage when mucosal equivalent light dose was administered during photodynamic therapy in the canine esophageal model.
Increasing centering balloon size resulted in reduced tissue damage when mucosal equivalent light dose was administered during photodynamic therapy in the canine esophageal model. Proper sizing of centering balloons will be necessary for balloon PDT of esophageal mucosal dysplasia or cancer in humans.
光动力疗法目前正用于治疗包括食管癌在内的各种恶性肿瘤。光动力疗法的效果取决于光敏药物的浓度、传递至组织的光能以及靶组织中氧气的存在。我们发现食管对中球囊可改善光向食管黏膜的传递。然而，球囊对食管黏膜的压力可能会降低黏膜血流和氧合，从而降低光动力疗法的效果。本研究旨在探讨犬食管模型光动力治疗期间球囊压力对食管壁的影响。
研究设计/材料与方法：在10只动物的犬食管中进行研究，以调查增加对中球囊的尺寸，进而增加对食管黏膜的压力，是否会改变光动力疗法的组织效应。给予4mg/kg的卟吩姆钠，并通过位于360度2cm开窗球囊中心的1cm扩散器传递630nm的光。进行黏膜光测量以确定等效黏膜光剂量约为25J/cm²。比较使用25mm、33mm和35mm球囊进行光动力治疗后获得的内镜和尸检结果。
在较大的犬（A组和B组）中，将食管对中球囊的尺寸从25mm增加到33mm不会导致贴合过紧，且这种增加与光动力疗法效果的显著变化无关。相比之下，在较小的犬（C组）中将球囊尺寸增加到35mm会导致球囊在食管中贴合过紧，并且在犬食管模型光动力治疗期间给予黏膜等效光剂量时，光动力疗法对黏膜损伤的效果显著降低。
在犬食管模型光动力治疗期间给予黏膜等效光剂量时，增加对中球囊尺寸会减少组织损伤。对于人类食管黏膜发育异常或癌症的球囊光动力治疗，对中球囊的合适尺寸是必要的。
