title: Esophageal self-expandable stent material and mesh grid density are the major determining factors of external beam radiation dose perturbation: results from a phantom model.
abstract: BACKGROUND
  Self-expandable esophageal stents are increasingly used for palliation or as an adjunct to chemoradiation for esophageal neoplasia. The optimal esophageal stent design and material to minimize dose perturbation with external beam radiation are unknown. We sought to quantify the deviation from intended radiation dose as a function of stent material and mesh density design.
  
  
  METHODS
  A laboratory dosimetric film model was used to quantify perturbation of intended radiation dose among 16 different esophageal stents with varying material and stent mesh density design.
  
  
  RESULTS
  Radiation dose enhancement due to stent backscatter ranged from 0 % to 7.3 %, collectively representing a standard difference from the intended mean radiation dose of 1.9 (95 % confidence interval [CI] 1.5 - 2.2). This enhancement was negligible for polymer-based stents and approached 0 % for the biodegradable stents. In contrast, all metal alloy stents had significant radiation backscatter; this was largely determined by the density of mesh design and not by the type of alloy used.
  
  
  CONCLUSIONS
  Stent characteristics should be considered when selecting the optimal stent for treatment and palliation of malignant esophageal strictures, especially when adjuvant or neo-adjuvant radiotherapy is planned.
authors.affiliation: Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, MN, USA.
authors.forename: B K
authors.initials: BK
authors.lastname: Abu Dayyeh
authors.forename: J J
authors.initials: JJ
authors.lastname: Vandamme
authors.forename: R C
authors.initials: RC
authors.lastname: Miller
authors.forename: T H
authors.initials: TH
authors.lastname: Baron
mesh_terms: D000497:Alloys; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D004867:Equipment Design; D004938:Esophageal Neoplasms / Q000532:radiotherapy*; D004940:Esophageal Stenosis / Q000532:radiotherapy; D006801:Humans; D010166:Palliative Care; D011108:Polymers; D011829:Radiation Dosage; D011874:Radiometry; D011879:Radiotherapy Dosage; D013193:Stainless Steel; D015607:Stents / Q000009:adverse effects; D013526:Surgical Mesh
chemical_list: D000497:Alloys; D011108:Polymers; D013193:Stainless Steel; C013616:nitinol