title: Physical and histopathological assessment of the effects of metallic stents on radiation therapy.
abstract: To evaluate whether simultaneous metallic stent (MS) placement and radiotherapy are feasible, phantom and animal experiments were performed. The interface dose by external irradiation (EI) or intracavity irradiation (II) to 5 kinds of MS was measured using the charge-coupled device (CCD) camera with a thermoluminescent (TL) sheet, and backscatter and absorption were evaluated using composite method. Lineac 10 MV X-ray irradiated the MS in close contact with the TL sheet. II was performed using (192)Ir, and the irradiation dose transmitted through the MS was measured using the TL sheet. The ratio of the CCD value of the MS wire region to that of the MS non-wire region was defined as the dose perturbation factor (DPF). Furthermore, the effects of a combination of (60)Co gamma-ray EI and MS placement in the normal common bile duct were histopathologically evaluated in dogs. In the phantom experiments of EI, in backscatter by the MS, the DPF was 1.09 for CZ, and 1.03 for Pal, but no backscatter was detected in the remaining 3 MS. In absorption by the MS, the DPF was 0.92, 0.97, 0.97, and 0.98 for CZ, Wall, Pal, and Vel, respectively, but no absorption was detected in U. Flex. In those of II, the DPF of absorption was 0.91, 0.98, and 0.98 for CZ, U. Flex, and Wall, respectively, but no absorption was detected in Pal and Vel. The animal experiments showed infiltration of inflammatory cells and fibrosis in the case of both MS placement and EI. These changes were marked in EI treating after MS placement, but neither severe ulcer nor perforation was found. In conclusion, these results suggested that the effect of MS should be considered carefully when simultaneous MS placement and EI is performed clinically.
authors.affiliation: Department of Radiation Oncology, Nara Medical University School of Medicine, Nara, Japan. ytsu@nmu-gw.naramed-u.ac.jp
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Tsuji
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Uto
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tamada
authors.forename: Kazuro
authors.initials: K
authors.lastname: Iwata
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Tamamoto
authors.forename: Isao
authors.initials: I
authors.lastname: Asakawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Shinkai
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Kichikawa
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hasegawa
mesh_terms: D000818:Animals; D016477:Artifacts; D003135:Common Bile Duct / Q000473:pathology* / Q000528:radiation effects* / Q000601:surgery; D003137:Common Bile Duct Diseases / Q000209:etiology / Q000473:pathology*; D004285:Dogs; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D008670:Metals / Q000009:adverse effects*; D011832:Radiation Injuries / Q000209:etiology / Q000473:pathology*; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D012542:Scattering, Radiation; D015607:Stents / Q000009:adverse effects*; D013739:Testosterone / Q000031:analogs & derivatives
chemical_list: D008670:Metals; D013739:Testosterone; C001371:boldenone undecylenate