title: Dual-isotope SPECT of skull-base invasion of head and neck tumors.
abstract: Skull-base invasions of head and neck tumors were examined by simultaneous bone and tumor dual-isotope SPECT (S-SPECT) with 99mTc-hydroxy-methylene-diphosphonate (99mTc-HMDP) and 201Tl-chloride. The effectiveness and reliability of tumor diagnosis by this method was the primary interest in this study.
  
  
  METHODS
  Before S-SPECT imaging, a phantom experiment using dried skull-bone specimens was performed to establish anatomical details of the skull base with the SPECT camera. Radionuclide crosstalk, window widths and control patients were also examined prior to S-SPECT imaging. Twenty patients with suspected tumor invasion of the skull base underwent S-SPECT.
  
  
  RESULTS
  Preliminary experiments revealed that crosstalk effects could be disregarded with adequate window width and routine administrative doses of the radionuclides. S-SPECT detected bone destruction and the extent of tumor invasion for all 12 patients in whom skull-base involvement was diagnosed by CT or MRI. For the three patients in whom CT or MRI revealed no tumor invasion, the S-SPECT images did not show any abnormal accumulation in similar regions. In the remaining five patients without CT and MRI confirmation of skull-base invasion, the S-SPECT findings showed skull-base abnormalities in three. Tumor invasion was confirmed surgically or by clinical follow-up. The remaining two patients had negative S-SPECT images.
  
  
  CONCLUSIONS
  S-SPECT is an effective and reliable diagnostic technique for detecting tumor invasion in the complex bony regions of the skull base.
authors.affiliation: Department of Radiology, Kochi Medical School, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Fukumoto
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: D
authors.initials: D
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Kishimoto
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D019047:Phantoms, Imaging; D011379:Prognosis; D012888:Skull Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D013669:Technetium Tc 99m Medronate / Q000031:analogs & derivatives*; D013793:Thallium; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014057:Tomography, X-Ray Computed
chemical_list: D013794:Thallium Radioisotopes; C027549:thallium chloride; C024226:technetium Tc 99m hydroxymethylene diphosphonate; D013793:Thallium; D013669:Technetium Tc 99m Medronate