title: Technical Note: Dose distributions in the vicinity of high-density implants using 3D gel dosimeters.
abstract: OBJECTIVE
  In this work, we develop a methodology for using Fricke gel dosimeters for dose distribution measurements surrounding high-density implants which circumvents artifact production by removing the obstruction during imaging.
  
  
  METHODS
  Custom 3D printed molds were used to set cavities in Fricke gel phantoms to allow for the suspension of high-density implants in different geometries. This allowed for the metal valve extracted from a temporary tissue expander to be suspended during irradiation, and removed during optical-CT scanning.
  
  
  RESULTS
  The removal of the metal implant and subsequent backfilling of the remaining cavity with optically matched fluid prior to dose evaluation enables accurate optical-CT scanning of the gel dosimeters. Results have shown very good agreement between measured and calculated doses within 2 mm from the surface of the implant. Slight deviations are present within 1 mm of the interface.
  
  
  CONCLUSIONS
  Artifacts in the form of radial streaking, cold spots, and hot spots were all reduced using this technique, enabling the broader and more accurate use of optical-CT for the imaging of gels containing opaque objects.
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
authors.forename: Andre
authors.initials: A
authors.lastname: Asena
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
authors.forename: Shaun Thomas
authors.initials: ST
authors.lastname: Smith
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.|Genesis CancerCare Queensland, The Wesley Medical Centre, Suite 1, 40 Chasely St, Auchenflower, QLD, 4066, Australia.
authors.forename: Tanya
authors.initials: T
authors.lastname: Kairn
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.|Cancer Care Services, Royal Brisbane & Women's Hospital, Butterfield Street, Herston, QLD, 4029, Australia.
authors.forename: Scott Bradley
authors.initials: SB
authors.lastname: Crowe
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Hosokawa
authors.affiliation: Cancer Care Services, Royal Brisbane & Women's Hospital, Butterfield Street, Herston, QLD, 4029, Australia.
authors.forename: Steven
authors.initials: S
authors.lastname: Sylvander
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
authors.forename: Jamie Vincent
authors.initials: JV
authors.lastname: Trapp
mesh_terms: D016477:Artifacts; D005782:Gels; D055620:Optical Phenomena; D019047:Phantoms, Imaging; D066330:Printing, Three-Dimensional; D019736:Prostheses and Implants; D000072232:Radiation Dosimeters; D014057:Tomography, X-Ray Computed
chemical_list: D005782:Gels
keywords: Fricke gel; filtered back projection; high-density implant; optical computed tomography