title: A modified relocatable stereotactic frame for irradiation of eye melanoma: design and evaluation of treatment accuracy.
abstract: OBJECTIVE
  To describe a reliable, patient-friendly relocatable stereotactic frame for irradiation of eye melanoma and to evaluate the repositioning accuracy of the stereotactic treatment.
  
  
  METHODS
  An extra construction with a blinking light and a camera is attached to a noninvasive relocatable Gill-Thomas-Cosman stereotactic frame. The position of the blinking light is in front of the unaffected eye and can be adjusted to achieve an optimal position for irradiation. The position of the diseased eye is monitored with a small camera. A planning CT scan is performed with the affected eye in treatment position and is matched with an MR scan to improve the accuracy of the delineation of the tumor. Both the translation and rotation of the affected eye are calculated by comparing the planning CT scan with a control CT scan, performed after the radiation therapy is completed.
  
  
  RESULTS
  Nineteen irradiated eye melanoma patients were analyzed. All patients received 5 fractions of 10 Gy within 5 days. The depth-confirmation helmet measurements of the day-to-day treatment position of the skull within the Gill-Thomas-Cosman frame were analyzed in the anteroposterior, lateral, and vertical directions and were 0.1 +/- 0.3, 0.0 +/- 0.2, and 0.2 +/- 0.2 mm (mean +/- SD), respectively. The average translations of the eye on the planning and control CT scan were 0.1 +/- 0.3 mm, 0.1 +/- 0.4, and 0.1 +/- 0.5 mm, respectively. The median rotation of the diseased eye was 8.3 degrees.
  
  
  CONCLUSIONS
  The described Rotterdam eye fixation system turned out to be a feasible, reliable, and patient-friendly system.
authors.affiliation: Department of Radiation Oncology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: Muller
authors.forename: Peter J C M
authors.initials: PJ
authors.lastname: Nowak
authors.forename: Grégorius P M
authors.initials: GP
authors.lastname: Luyten
authors.forename: Johannes P
authors.initials: JP
authors.lastname: Marijnissen
authors.forename: Connie
authors.initials: C
authors.lastname: de Pan
authors.forename: Peter
authors.initials: P
authors.lastname: Levendag
mesh_terms: D004867:Equipment Design; D005134:Eye Neoplasms / Q000601:surgery*; D006801:Humans; D007103:Immobilization; D008545:Melanoma / Q000601:surgery*; D008875:Middle Aged; D016634:Radiosurgery / Q000295:instrumentation*