title: A newly developed intra-operative gamma camera: performance characteristics in a laboratory phantom study.
abstract: OBJECTIVE
  Radioguided surgery depends on the intra-operative detection of radiolabelled tissues. This is currently accomplished with hand tools capable of providing a tone signal, depending on the proximity and direction of a radioactive source in relation to the probe. The advantages of visual images of radiolabelled tissues are well recognised, but satisfactory means of acquiring such images intra-operatively are not yet available. The goal of this study was to examine the performance of a newly developed intra-operative gamma camera, compact enough to be a hand tool and capable of yielding a visual image of the source field.
  
  
  METHODS
  The study was performed in the laboratory with a phantom consisting of a water bath and small hollow spheres (1-2 cm in internal diameter) filled with 99mTc (1-5 microCi/cc), placed in different configurations within the bath. For comparison, studies were also performed using a standard intra-operative gamma probe, and others using a standard single-head high-resolution gamma camera.
  
  
  RESULTS
  Compared with the gamma probe, the intra-operative camera was found to possess a superior ability to distinguish small, deep and weakly localised radioactivity sources from background. By acquiring images from different angles, it allowed a 3D understanding of multiple radioactive sources. It detected "cold" defects within a "hot" radiolabelled sphere. It discriminated a weak source located near a much "hotter" radioactivity source, similar to discrimination with the standard gamma camera, and discerned localised sources against a background of radioactivity.
  
  
  CONCLUSIONS
  It is anticipated that the high imaging potential of the camera tested in this study will offer clinical advantages.
authors.affiliation: Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
authors.forename: Doron
authors.initials: D
authors.lastname: Kopelman
authors.forename: Ira
authors.initials: I
authors.lastname: Blevis
authors.forename: Galina
authors.initials: G
authors.lastname: Iosilevsky
authors.forename: Alla
authors.initials: A
authors.lastname: Reznik
authors.forename: Alex
authors.initials: A
authors.lastname: Chaikov
authors.forename: Naor
authors.initials: N
authors.lastname: Weiner
authors.forename: Ora
authors.initials: O
authors.lastname: Israel
authors.forename: Moshe
authors.initials: M
authors.lastname: Hashmonai
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D015902:Gamma Cameras; D007089:Image Enhancement / Q000295:instrumentation*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods