title: Monitoring of hexyl 5-aminolevulinate-induced photodynamic therapy in rat bladder cancer by optical spectroscopy.
abstract: 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.
authors.affiliation: Norwegian University of Science and Technology, Department of Electronics and Telecommunications, N-7034 Trondheim, Norway. eivind.larsen@iet.ntnu.no
authors.forename: Eivind L P
authors.initials: EL
authors.lastname: Larsen
authors.forename: Lise L
authors.initials: LL
authors.lastname: Randeberg
authors.forename: Odrun A
authors.initials: OA
authors.lastname: Gederaas
authors.forename: Carl-Jørgen
authors.initials: CJ
authors.lastname: Arum
authors.forename: Astrid
authors.initials: A
authors.lastname: Hjelde
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Zhao
authors.forename: Duan
authors.initials: D
authors.lastname: Chen
authors.forename: Hans E
authors.initials: HE
authors.lastname: Krokan
authors.forename: Lars O
authors.initials: LO
authors.lastname: Svaasand
mesh_terms: D000622:Aminolevulinic Acid / Q000008:administration & dosage*; D000818:Animals; D045744:Cell Line, Tumor; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011379:Prognosis; D051381:Rats; D011916:Rats, Inbred F344; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*; D016896:Treatment Outcome; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000188:drug therapy*
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid