title: Multimodality cranial image fusion using external markers applied via a vacuum mouthpiece and a case report.
abstract: OBJECTIVE
  To present a simple and precise method of combining functional information of cranial SPECT and PET images with CT and MRI, in any combination.
  
  
  METHODS
  Imaging is performed with a hockey mask-like reference frame with image modality-specific markers in precisely defined positions. This frame is reproducibly connected to the VBH vacuum mouthpiece, granting objectively identical repositioning of the frame with respect to the cranium. Using these markers, the desired 3-D imaging modalities can then be manually or automatically registered. This information can be used for diagnosis, treatment planning, and evaluation of follow-up, while the same vacuum mouthpiece allows precisely reproducible stereotactic head fixation during radiotherapy.
  
  
  RESULTS
  244 CT and MR data sets of 49 patients were registered to a root square mean error (RSME) of 0.9 mm (mean). 64 SPECT-CT fusions on 18 of these patients gave an RMSE of 1.4 mm, and 40 PET-CT data sets of eight patients were registered to 1.3 mm. An example of the method is given by means of a case report of a 52-year-old patient with bilateral optic nerve meningioma.
  
  
  CONCLUSIONS
  This technique is a simple, objective and accurate registration tool to combine diagnosis, treatment planning, treatment, and follow-up, all via an individualized vacuum mouthpiece. Especially for low-resolution PET and even more so for some very diffuse SPECT data sets, activity can now be accurately correlated to anatomic structures.
authors.affiliation: Department of Radiotherapy-Radiooncology, University Hospital Innsbruck, Austria. reinhart.sweeny@uibk.ac.at
authors.forename: Reinhart A
authors.initials: RA
authors.lastname: Sweeney
authors.forename: Reto J
authors.initials: RJ
authors.lastname: Bale
authors.forename: Roy
authors.initials: R
authors.lastname: Moncayo
authors.forename: Karl
authors.initials: K
authors.lastname: Seydl
authors.forename: Thomas
authors.initials: T
authors.lastname: Trieb
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Eisner
authors.forename: Johannes
authors.initials: J
authors.lastname: Burtscher
authors.forename: Eveline
authors.initials: E
authors.lastname: Donnemiller
authors.forename: Günther
authors.initials: G
authors.lastname: Stockhammer
authors.forename: Peter
authors.initials: P
authors.lastname: Lukas
mesh_terms: D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006257:Head; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008579:Meningioma / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D008875:Middle Aged; D009064:Mouth Protectors; D019574:Optic Nerve Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011878:Radiotherapy / Q000295:instrumentation*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D013997:Time Factors; D014055:Tomography, Emission-Computed / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014618:Vacuum