title: Safety testing of epimacular brachytherapy with microperimetry and indocyanine green angiography: 12-month results.
abstract: OBJECTIVE
  To determine if epimacular brachytherapy is associated with reduced retinal sensitivity or choroidal nonperfusion.
  
  
  METHODS
  A prospective intervention case series of 12 participants with neovascular age-related macular degeneration requiring frequent ranibizumab underwent vitrectomy and epimacular brachytherapy. The Strontium 90/Yttrium 90 source delivered a single 24-Gy dose at the center of the treatment zone. The dose attenuated with increasing distance from the source. Microperimetry and indocyanine green angiography were performed at baseline and 12 months. The main outcome measures were mean sensitivity and choroidal nonperfusion. A linear mixed model was used to assess the association between the dose of radiation and the change in mean sensitivity.
  
  
  RESULTS
  Mean visual acuity remained within 1 letter of baseline at 12 months (-0.33 ± 13.2 letters). There was no statistically significant change in mean sensitivity within the neovascular age-related macular degeneration lesion area (gain of 0.94 ± 3.25 dB; P = 0.339) or in neighboring unaffected retina (0.66 ± 4.14 dB; P = 0.594), defined using fluorescein angiography. Within the lesion area, mean sensitivity improved by an average of 0.23 ± 0.16 dB (P = 0.006) for every additional gray of radiation received. Indocyanine green angiography failed to demonstrate any choroidal nonperfusion or radiation damage at 12 months after the treatment.
  
  
  CONCLUSIONS
  Stable retinal sensitivity in areas not manifestly affected by neovascular age-related macular degeneration suggests that epimacular brachytherapy does not damage retinal function. The presence of a dose response suggests that the positive effect of epimacular brachytherapy relates more to beta irradiation than vitrectomy.
authors.affiliation: King's College Hospital, London, United Kingdom.
authors.forename: Robert
authors.initials: R
authors.lastname: Petrarca
authors.forename: Matthew
authors.initials: M
authors.lastname: Richardson
authors.forename: Abdel
authors.initials: A
authors.lastname: Douiri
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Nau
authors.forename: Dominic
authors.initials: D
authors.lastname: McHugh
authors.forename: Alexandros N
authors.initials: AN
authors.lastname: Stangos
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Jackson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020533:Angiogenesis Inhibitors / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods; D006801:Humans; D007208:Indocyanine Green; D016014:Linear Models; D008268:Macular Degeneration / Q000503:physiopathology / Q000532:radiotherapy* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011832:Radiation Injuries / Q000175:diagnosis*; D000069579:Ranibizumab; D012160:Retina / Q000528:radiation effects*; D012684:Sensory Thresholds / Q000502:physiology; D013326:Strontium Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*; D014821:Vitrectomy; D015021:Yttrium Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D013326:Strontium Radioisotopes; D015021:Yttrium Radioisotopes; D007208:Indocyanine Green; D000069579:Ranibizumab