title: Dosimetry of a 188rhenium-labeled self-expanding stent for endovascular brachytherapy in peripheral arteries.
abstract: OBJECTIVE
  Radioactive stents have been proposed as endovascular irradiation device to prevent in-stent restenosis by inhibiting neointimal proliferation. 32P-stents have been used in several studies so far, but require large-scale labeling procedures and endovascular barotrauma for stent expansion supporting the development of edge restenosis. Purpose of this study was to establish dosimetry of a self-expanding nitinol stent for peripheral vascular disease, which was radiolabeled with 188rhenium (188Re) by a dip coating technique.
  
  
  METHODS
  The surface of nitinol Memotherm FLEXX stents was polymer-coated providing functional NH(2) groups for diethylenetriaminepentaacetic acid (DTPA) binding, providing the ligand for the complexation of 188Re onto the stent surface. Stability of radiolabeling was tested over 48 h using an in vitro blood circulation (Chandler Loop). Radial and longitudinal dose distributions of a radiolabeled stent were obtained with a plastic scintillator dosimetry system.
  
  
  RESULTS
  Stents with a length of 30 mm and a diameter of 8 mm were labeled with up to 33 MBq 188Re. A total of 69+/-4% of the labeled 188Re remained stable on the stent surface after 48 h. Ninety-five percent of the infinitely accumulated dose was supplied to the target tissue within 72 h. Including correction for radioactivity washout from the stent, the infinitely accumulated dose at 1 mm radial distance from the stent surface was 1.85+/-0.19 Gy/MBq 188Re/cm stent length.
  
  
  CONCLUSIONS
  We developed a technique for radiolabeling of self-expanding nitinol stents with 188Re by dip coating and formation of 188Re chelate complexes. We provide dosimetry data useful for application of this beta-emitting stent for endovascular brachytherapy in peripheral vascular occlusive disease.
authors.affiliation: Department of Nuclear Medicine, Aachen University of Technology, Pauwelsstrasse 30, 52074 Aachen, Germany. bnowak@ukaachen.de
authors.forename: B
authors.initials: B
authors.lastname: Nowak
authors.forename: J M
authors.initials: JM
authors.lastname: Meyer
authors.forename: T
authors.initials: T
authors.lastname: Goergen
authors.forename: D
authors.initials: D
authors.lastname: Fluehs
authors.forename: S
authors.initials: S
authors.lastname: Block
authors.forename: R W
authors.initials: RW
authors.lastname: Guenther
authors.forename: H
authors.initials: H
authors.lastname: Hoecker
authors.forename: U
authors.initials: U
authors.lastname: Buell
mesh_terms: D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D016491:Peripheral Vascular Diseases / Q000532:radiotherapy*; D011868:Radioisotopes; D011874:Radiometry; D012211:Rhenium / Q000627:therapeutic use*; D015607:Stents
chemical_list: D011868:Radioisotopes; D012211:Rhenium