Larsen Eivind L P, Randeberg Lise L, Gederaas Odrun A, Arum Carl-Jørgen, Hjelde Astrid, Zhao Chun-Mei, Chen Duan, Krokan Hans E, Svaasand Lars O
Norwegian University of Science and Technology, Department of Electronics and Telecommunications, N-7034 Trondheim, Norway.
J Biomed Opt. 2008 Jul-Aug;13(4):044031. doi: 10.1117/1.2967909.
Monitoring of the tissue response to photodynamic therapy (PDT) can provide important information to help optimize treatment variables such as drug and light dose, and possibly predict treatment outcome. A urinary bladder cancer cell line (AY-27) was used to induce orthotopic transitional cell carcinomas (TCC) in female Fischer rats, and hexyl 5-aminolevulinate (HAL, 8 mM, 1 h)-induced PDT was performed on day 14 after instillation of the cancer cells (20 J/cm(2) fluence at 635 nm). In vivo optical reflectance and fluorescence spectra were recorded from bladders before and after laser treatment with a fiberoptic probe. Calculated fluorescence bleaching and oxygen saturation in the bladder wall were examined and correlated to histology results. Reflectance spectra were analyzed using a three-layer optical photon transport model. Animals with TCC treated with PDT showed a clear treatment response; decreased tissue oxygenation and protoporphyrin IX (PpIX) fluorescence photobleaching were observed. Histology demonstrated that 3 of 6 animals with treatment had no sign of the tumor 7 days after PDT treatment. The other 3 animals had significantly reduced the tumor size. The most treatment-responsive animals had the highest PpIX fluorescence prior to light irradiation. Thus, optical spectroscopy can provide useful information for PDT. The model has proved to be very suitable for bladder cancer studies.
监测组织对光动力疗法（PDT）的反应可为优化治疗变量（如药物和光剂量）提供重要信息，并可能预测治疗结果。使用膀胱癌细胞系（AY - 27）在雌性Fischer大鼠中诱导原位移行细胞癌（TCC），并在接种癌细胞后第14天进行5 - 氨基乙酰丙酸己酯（HAL，8 mM，1小时）诱导的PDT（635 nm波长下通量为20 J/cm²）。在用光纤探头进行激光治疗前后，从膀胱记录体内光学反射率和荧光光谱。检查并将膀胱壁中计算出的荧光漂白和氧饱和度与组织学结果相关联。使用三层光学光子传输模型分析反射光谱。接受PDT治疗的TCC动物表现出明显的治疗反应；观察到组织氧合降低和原卟啉IX（PpIX）荧光漂白。组织学表明，6只接受治疗的动物中有3只在PDT治疗7天后无肿瘤迹象。另外3只动物的肿瘤大小显著减小。对治疗反应最敏感的动物在光照前具有最高的PpIX荧光。因此，光谱学可为PDT提供有用信息。该模型已被证明非常适合膀胱癌研究。
