Molecular Imaging Instrumentation Laboratory  

Intra-Operative Beta (Positron or Electron) Detectors and Cameras

We have been studying the concept of miniature camera that can perform real-time imaging of molecular signatures of disease in situ, that is, when placed directly on top of the diseased tissue.  The molecular signatures come from existing, clinically approved cancer-avid molecular contrast agents. One example agent is 18F-fluorodeoxyglucose (FDG), a common analog marker for over-expression of certain glucose transporters on cancer cells as well as up-regulation of activity of the enzyme hexokinase inside cancer cells. 18F is a radionuclide label that emits positrons. This radioactive FDG marker has been very successful in cancer imaging using positron emission tomography (PET). Clinical PET imaging of 511 keV photons transported out of the body into distant detectors is relatively insensitive; only 1 out of 100 photon pairs are collected in the standard PET scanner.  Standard clinical PET also has relatively low spatial resolution of ~7-13 millimeters, and has limited contrast resolution due to significant background annihilation photon contamination from other parts of the body. As a result, of its relatively poor photon sensitivity, spatial resolution, and contrast resolution, PET has very low sensitivity for detecting a small population of cancer cells, as is the case, for example, for evaluating tumor margins during surgery.

Positron DetectorPositron Range

    However, the approach we are proposing to solve these problems and enable resolution of a small population of diseased cells is not PET imaging. In contrast, in the proposed innovative camera the imaging signal comes directly from the 18F positron emissions that are absorbed in a sensor before they annihilate; that is, they annihilate in the sensor instead of in the tissue, and we want to directly detect the positrons, not the resulting annihilation photons.  In order for this to occur, the imaging sensor is located in situ, for example, in a surgical cavity, in contact with the tumor margins during surgical resection of a primary tumor. This proposed direct contact of the imaging sensor with the tumor margins means that the positron detection probability is extremely high.  Also, the positron distance traveled before it stops (a.k.a. “range”) is <250 microns on average in tissue, and <100 micron on average in the sensor material.  Thus, in this direct contact scenario the positron imaging sensor only detects a signal when the diseased (e.g. tumor) cells are at or very near the margin surface and the intrinsic spatial resolution is on the order of 100 microns or better, which is adequate to visualize a small population of cells that accumulated the radio-labeled biochemical marker.  One challenge is to design the sensor to be very thin so that there is very little annihilation photon background detected, since the chance that a highly-penetrating 511 keV photon will interact with the very thin sensor is extremely small.

People Involved

Related Publications

Global QuickSearch:   Number of matching entries: 0

Search Settings

    Author Title Year Jour./Proc./Book
    Hoffman, E.J.; Tornai, M.P.; Levin, C.S.; MacDonald, L.R. & Holdsworth, C.H. A Dual Detector Beta-Ray Imaging Probe with Gamma-Ray Background Suppression for Use in Intra-Operative Detection of Radiolabeled Tumors 1998 Nuclear Instruments and Methods in Physics Research A
    Vol. 409, pp. 511-516  
    BibTeX:
    @article{Hoffman1998,
      author = {E. J. Hoffman and M. P. Tornai and C. S. Levin and L. R. MacDonald and C. H. Holdsworth},
      title = {A Dual Detector Beta-Ray Imaging Probe with Gamma-Ray Background Suppression for Use in Intra-Operative Detection of Radiolabeled Tumors},
      journal = {Nuclear Instruments and Methods in Physics Research A},
      year = {1998},
      volume = {409},
      pages = {511-516}
    }
    					
    Hoffman, E.J.; Tornai, M.P.; Levin, C.S.; MacDonald, L.R. & Siegel, S. Design and Performance of Gamma and Beta Intra-Operative Imaging Probes 1997 Physica Medica
    Vol. 13, pp. S243-247  
    BibTeX:
    @article{Hoffman1997,
      author = {E. J. Hoffman and M. P. Tornai and C. S. Levin and L. R. MacDonald and S. Siegel},
      title = {Design and Performance of Gamma and Beta Intra-Operative Imaging Probes},
      journal = {Physica Medica},
      year = {1997},
      volume = {13},
      pages = {S243-247}
    }
    					
    Hoffman, E.J.; Tornai, M.P.; Levin, C.S.; MacDonald, L.R. & Siegel, S. Gamma and Beta Intra-Operative Imaging Probes 1997 Nuclear Instruments and Methods in Physics Research A
    Vol. 392, pp. 324-329  
    BibTeX:
    @article{Hoffman1997a,
      author = {E. J. Hoffman and M. P. Tornai and C. S. Levin and L. R. MacDonald and S. Siegel},
      title = {Gamma and Beta Intra-Operative Imaging Probes},
      journal = {Nuclear Instruments and Methods in Physics Research A},
      year = {1997},
      volume = {392},
      pages = {324-329}
    }
    					
    Levin, C.S.; MacDonald, L.R.; Tornai, M.P.; Hoffman, E.J. & Park, J. Optimizing Light Collection from Thin Scintillators Used in a Beta-Ray Camera for Surgical Use 1996 IEEE Transactions on Nuclear Science
    Vol. 43-3, pp. 2053-2060  
    BibTeX:
    @article{Levin1996,
      author = {C. S. Levin and L. R. MacDonald and M. P. Tornai and E. J. Hoffman and J. Park},
      title = {Optimizing Light Collection from Thin Scintillators Used in a Beta-Ray Camera for Surgical Use},
      journal = {IEEE Transactions on Nuclear Science},
      year = {1996},
      volume = {43-3},
      number = {2},
      pages = {2053-2060}
    }
    					
    Levin, C.S.; MacDonald, L.R.; Tornai, M.P.; Hoffman, E.J. & Park, J. Optimizing Light Collection from Thin Scintillators Used in a Beta-Ray Camera for Surgical Use 1995 Conference Record of the 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference, III, pp. 1796-1800  
    BibTeX:
    @inproceedings{Levin,
      author = {C. S. Levin and L. R. MacDonald and M. P. Tornai and E. J. Hoffman and J. Park},
      title = {Optimizing Light Collection from Thin Scintillators Used in a Beta-Ray Camera for Surgical Use},
      booktitle = {Conference Record of the 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference, III},
      year = {1995},
      pages = {1796-1800}
    }
    					
    Levin, C.S.; Tornai, M.P.; MacDonald, L.R. & Hoffman, E.J. Annihilation Gamma-Ray Background Characterization and Rejection for a Small Beta Camera Used for Tumor Localization During Surgery 1997 IEEE Transactions on Nuclear Science
    Vol. 44-4, pp. 1120-1126  
    BibTeX:
    @article{Levin1997a,
      author = {C. S. Levin and M. P. Tornai and L. R. MacDonald and E. J. Hoffman},
      title = {Annihilation Gamma-Ray Background Characterization and Rejection for a Small Beta Camera Used for Tumor Localization During Surgery},
      journal = {IEEE Transactions on Nuclear Science},
      year = {1997},
      volume = {44-4},
      pages = {1120-1126}
    }
    					
    MacDonald, L.R.; Tornai, M.P.; Levin, C.S.; Park, J.; Atac, M.; Cline, D.B. & Hoffman, E.J. Investigation of the Physical Aspects of Beta Imaging Probes Using Scintillating Fibers and Visible Light Photon Counters 1995 IEEE Transactions on Nuclear Science
    Vol. 42-4, pp. 1351-1357  
    BibTeX:
    @article{MacDonald1995,
      author = {L. R. MacDonald and M. P. Tornai and C. S. Levin and J. Park and M. Atac and D. B. Cline and E. J. Hoffman},
      title = {Investigation of the Physical Aspects of Beta Imaging Probes Using Scintillating Fibers and Visible Light Photon Counters},
      journal = {IEEE Transactions on Nuclear Science},
      year = {1995},
      volume = {42-4},
      pages = {1351-1357}
    }
    					
    MacDonald, L.R.; Tornai, M.P.; Levin, C.S.; Park, J.; Atac, M.; Cline, D.B. & Hoffman, E.J. Small Area, Fiber Coupled Scintillation Camera for Imaging Beta-Ray Distributions Intra-Operatively 1995 Photoelectronic Detectors, Cameras and Systems, Proceedings of SPIE, the International Society for Optical Engineering, pp. 92-101  
    BibTeX:
    @inproceedings{MacDonald1995a,
      author = {L. R. MacDonald and M. P. Tornai and C. S. Levin and J. Park and M. Atac and D. B. Cline and E. J. Hoffman},
      title = {Small Area, Fiber Coupled Scintillation Camera for Imaging Beta-Ray Distributions Intra-Operatively},
      booktitle = {Photoelectronic Detectors, Cameras and Systems, Proceedings of SPIE, the International Society for Optical Engineering},
      year = {1995},
      pages = {92-101}
    }
    					
    MacDonald, L.R.; Tornai, M.P.; Levin, C.S.; Park, J.; Atac, M.; Cline, D.B. & Hoffman, E.J. Investigation of the Physical Aspects of Beta Imaging Probes Using Scintillating Fibers and Visible Light Photon Counters 1994 Conference Record of the 1994 IEEE Nuclear Science Symposium and Medical Imaging Conference, II, pp. 1380-1384  
    BibTeX:
    @conference{MacDonald1994,
      author = {L. R. MacDonald and M. P. Tornai and C. S. Levin and J. Park and M. Atac and D. B. Cline and E. J. Hoffman},
      title = {Investigation of the Physical Aspects of Beta Imaging Probes Using Scintillating Fibers and Visible Light Photon Counters},
      booktitle = {Conference Record of the 1994 IEEE Nuclear Science Symposium and Medical Imaging Conference, II},
      year = {1994},
      pages = {1380-1384}
    }
    					
    Tornai, M.P.; Hoffman, E.J.; Levin, C.S. & MacDonald, L.R. Characterization of Fluor Concentration and Geometry in Organic Scintillators for in situ Beta Imaging 1996 IEEE Transactions on Nuclear Science
    Vol. 43-6, pp. 3342-3347  
    BibTeX:
    @article{Tornai1996a,
      author = {M. P. Tornai and E. J. Hoffman and C. S. Levin and L. R. MacDonald},
      title = {Characterization of Fluor Concentration and Geometry in Organic Scintillators for in situ Beta Imaging},
      journal = {IEEE Transactions on Nuclear Science},
      year = {1996},
      volume = {43-6},
      pages = {3342-3347}
    }
    					
    Tornai, M.P.; Hoffman, E.J.; Levin, C.S. & MacDonald, L.R. Characterization of Fluor Concentration and Geometry in Organic Scintillators for in situ Beta Imaging 1995 Conference Record of the 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference, III, pp. 1632-1636  
    BibTeX:
    @conference{Tornai1995a,
      author = {M. P. Tornai and E. J. Hoffman and C. S. Levin and L. R. MacDonald},
      title = {Characterization of Fluor Concentration and Geometry in Organic Scintillators for in situ Beta Imaging},
      booktitle = {Conference Record of the 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference, III},
      year = {1995},
      pages = {1632-1636}
    }
    					
    Tornai, M.P.; Levin, C.S.; MacDonald, L.R.; Holdsworth, C.H. & Hoffman, E.J. A Miniature Phoswich Detector for Gamma-Ray Localization and Beta Imaging 1998 IEEE Transactions on Nuclear Science
    Vol. 45-3, pp. 1166-1173  
    BibTeX:
    @article{Tornai1998,
      author = {M. P. Tornai and C. S. Levin and L. R. MacDonald and C. H. Holdsworth and E. J. Hoffman},
      title = {A Miniature Phoswich Detector for Gamma-Ray Localization and Beta Imaging},
      journal = {IEEE Transactions on Nuclear Science},
      year = {1998},
      volume = {45-3},
      number = {2},
      pages = {1166-1173}
    }
    					
    Tornai, M.P.; Levin, C.S.; MacDonald, L.R.; Holdsworth, C.H. & Hoffman, E.J. A Miniature Phoswich Detector for Gamma-Ray Localization and Beta Imaging 1997 1997 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, II, pp. 1028-1032  
    BibTeX:
    @conference{Tornai1997b,
      author = {M. P. Tornai and C. S. Levin and L. R. MacDonald and C. H. Holdsworth and E. J. Hoffman},
      title = {A Miniature Phoswich Detector for Gamma-Ray Localization and Beta Imaging},
      booktitle = {1997 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, II},
      year = {1997},
      pages = {1028-1032}
    }
    					
    Tornai, M.P.; MacDonald, L.R.; Levin, C.S.; Siegel, S. & Hoffman, E.J. Design Considerations and Initial Performance of a 1.2 cm^2 Beta Imaging Intra-Operative Probe 1996 IEEE Transactions on Nuclear Science
    Vol. 43-4, pp. 2326-2335  
    BibTeX:
    @article{Tornai1996,
      author = {M. P. Tornai and L. R. MacDonald and C. S. Levin and S. Siegel and E. J. Hoffman},
      title = {Design Considerations and Initial Performance of a 1.2 cm^2 Beta Imaging Intra-Operative Probe},
      journal = {IEEE Transactions on Nuclear Science},
      year = {1996},
      volume = {43-4},
      number = {1},
      pages = {2326-2335}
    }
    					
    Tornai, M.P.; MacDonald, L.R.; Levin, C.S.; Siegel, S. & Hoffman, E.J. Design Considerations and Initial Performance of a 1.2 cm^2 Beta Imaging Intra-Operative Probe 1995 Conference Record of the 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference, III, pp. 1791-1795  
    BibTeX:
    @conference{Tornai1995,
      author = {M. P. Tornai and L. R. MacDonald and C. S. Levin and S. Siegel and E. J. Hoffman},
      title = {Design Considerations and Initial Performance of a 1.2 cm^2 Beta Imaging Intra-Operative Probe},
      booktitle = {Conference Record of the 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference, III},
      year = {1995},
      pages = {1791-1795}
    }
    					

    Footer Links: