A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images

T. Nishiyama, Jun Kataoka, A. Kishimoto, T. Fujita, Y. Iwamoto, T. Taya, S. Ohsuka, S. Nakamura, M. Hirayanagi, N. Sakurai, S. Adachi, T. Uchiyama

    Research output: Contribution to journalArticle

    1 Citation (Scopus)

    Abstract

    After the Japanese nuclear disaster in 2011, large amounts of radioactive isotopes were released and still remain a serious problem in Japan. Consequently, various gamma cameras are being developed to help identify radiation hotspots and ensure effective decontamination operation. The Compton camera utilizes the kinematics of Compton scattering to contract images without using a mechanical collimator, and features a wide field of view. For instance, we have developed a novel Compton camera that features a small size (13×14×15 cm3) and light weight (1.9 kg), but which also achieves high sensitivity thanks to Ce:GAGG scintillators optically coupled wiith MPPC arrays. By definition, in such a Compton camera, gamma rays are expected to scatter in the "scatterer" and then be fully absorbed in the "absorber" (in what is called a forwardscattered event). However, high energy gamma rays often interact with the detector in the opposite direction - initially scattered in the absorber and then absorbed in the scatterer - in what is called a "back-scattered" event. Any contamination of such back-scattered events is known to substantially degrade the quality of gamma-ray images, but determining the order of gamma-ray interaction based solely on energy deposits in the scatterer and absorber is quite difficult. For this reason, we propose a novel yet simple Compton camera design that includes a rear-panel shield (a few mm thick) consisting of W or Pb located just behind the scatterer. Since the energy of scattered gamma rays in back-scattered events is much lower than that in forward-scattered events, we can effectively discriminate and reduce back-scattered events to improve the signal-to-noise ratio in the images. This paper presents our detailed optimization of the rear-panel shield using Geant4 simulation, and describes a demonstration test using our Compton camera.

    Original languageEnglish
    Article numberC12031
    JournalJournal of Instrumentation
    Volume9
    Issue number12
    DOIs
    Publication statusPublished - 2014 Dec 15

    Fingerprint

    Noise Reduction
    Gamma Rays
    Noise abatement
    noise reduction
    Gamma rays
    Camera
    Cameras
    cameras
    gamma rays
    Absorber
    absorbers
    scattering
    Compton scattering
    decontamination
    Decontamination
    disasters
    Scintillator
    collimators
    Radioisotopes
    Wide-field

    Keywords

    • Compton imaging
    • Models and simulations

    ASJC Scopus subject areas

    • Instrumentation
    • Mathematical Physics

    Cite this

    A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images. / Nishiyama, T.; Kataoka, Jun; Kishimoto, A.; Fujita, T.; Iwamoto, Y.; Taya, T.; Ohsuka, S.; Nakamura, S.; Hirayanagi, M.; Sakurai, N.; Adachi, S.; Uchiyama, T.

    In: Journal of Instrumentation, Vol. 9, No. 12, C12031, 15.12.2014.

    Research output: Contribution to journalArticle

    Nishiyama, T, Kataoka, J, Kishimoto, A, Fujita, T, Iwamoto, Y, Taya, T, Ohsuka, S, Nakamura, S, Hirayanagi, M, Sakurai, N, Adachi, S & Uchiyama, T 2014, 'A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images', Journal of Instrumentation, vol. 9, no. 12, C12031. https://doi.org/10.1088/1748-0221/9/12/C12031
    Nishiyama, T. ; Kataoka, Jun ; Kishimoto, A. ; Fujita, T. ; Iwamoto, Y. ; Taya, T. ; Ohsuka, S. ; Nakamura, S. ; Hirayanagi, M. ; Sakurai, N. ; Adachi, S. ; Uchiyama, T. / A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images. In: Journal of Instrumentation. 2014 ; Vol. 9, No. 12.
    @article{adcf9aead072493c892a60d95e37b3d8,
    title = "A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images",
    abstract = "After the Japanese nuclear disaster in 2011, large amounts of radioactive isotopes were released and still remain a serious problem in Japan. Consequently, various gamma cameras are being developed to help identify radiation hotspots and ensure effective decontamination operation. The Compton camera utilizes the kinematics of Compton scattering to contract images without using a mechanical collimator, and features a wide field of view. For instance, we have developed a novel Compton camera that features a small size (13×14×15 cm3) and light weight (1.9 kg), but which also achieves high sensitivity thanks to Ce:GAGG scintillators optically coupled wiith MPPC arrays. By definition, in such a Compton camera, gamma rays are expected to scatter in the {"}scatterer{"} and then be fully absorbed in the {"}absorber{"} (in what is called a forwardscattered event). However, high energy gamma rays often interact with the detector in the opposite direction - initially scattered in the absorber and then absorbed in the scatterer - in what is called a {"}back-scattered{"} event. Any contamination of such back-scattered events is known to substantially degrade the quality of gamma-ray images, but determining the order of gamma-ray interaction based solely on energy deposits in the scatterer and absorber is quite difficult. For this reason, we propose a novel yet simple Compton camera design that includes a rear-panel shield (a few mm thick) consisting of W or Pb located just behind the scatterer. Since the energy of scattered gamma rays in back-scattered events is much lower than that in forward-scattered events, we can effectively discriminate and reduce back-scattered events to improve the signal-to-noise ratio in the images. This paper presents our detailed optimization of the rear-panel shield using Geant4 simulation, and describes a demonstration test using our Compton camera.",
    keywords = "Compton imaging, Models and simulations",
    author = "T. Nishiyama and Jun Kataoka and A. Kishimoto and T. Fujita and Y. Iwamoto and T. Taya and S. Ohsuka and S. Nakamura and M. Hirayanagi and N. Sakurai and S. Adachi and T. Uchiyama",
    year = "2014",
    month = "12",
    day = "15",
    doi = "10.1088/1748-0221/9/12/C12031",
    language = "English",
    volume = "9",
    journal = "Journal of Instrumentation",
    issn = "1748-0221",
    publisher = "IOP Publishing Ltd.",
    number = "12",

    }

    TY - JOUR

    T1 - A novel Compton camera design featuring a rear-panel shield for substantial noise reduction in gamma-ray images

    AU - Nishiyama, T.

    AU - Kataoka, Jun

    AU - Kishimoto, A.

    AU - Fujita, T.

    AU - Iwamoto, Y.

    AU - Taya, T.

    AU - Ohsuka, S.

    AU - Nakamura, S.

    AU - Hirayanagi, M.

    AU - Sakurai, N.

    AU - Adachi, S.

    AU - Uchiyama, T.

    PY - 2014/12/15

    Y1 - 2014/12/15

    N2 - After the Japanese nuclear disaster in 2011, large amounts of radioactive isotopes were released and still remain a serious problem in Japan. Consequently, various gamma cameras are being developed to help identify radiation hotspots and ensure effective decontamination operation. The Compton camera utilizes the kinematics of Compton scattering to contract images without using a mechanical collimator, and features a wide field of view. For instance, we have developed a novel Compton camera that features a small size (13×14×15 cm3) and light weight (1.9 kg), but which also achieves high sensitivity thanks to Ce:GAGG scintillators optically coupled wiith MPPC arrays. By definition, in such a Compton camera, gamma rays are expected to scatter in the "scatterer" and then be fully absorbed in the "absorber" (in what is called a forwardscattered event). However, high energy gamma rays often interact with the detector in the opposite direction - initially scattered in the absorber and then absorbed in the scatterer - in what is called a "back-scattered" event. Any contamination of such back-scattered events is known to substantially degrade the quality of gamma-ray images, but determining the order of gamma-ray interaction based solely on energy deposits in the scatterer and absorber is quite difficult. For this reason, we propose a novel yet simple Compton camera design that includes a rear-panel shield (a few mm thick) consisting of W or Pb located just behind the scatterer. Since the energy of scattered gamma rays in back-scattered events is much lower than that in forward-scattered events, we can effectively discriminate and reduce back-scattered events to improve the signal-to-noise ratio in the images. This paper presents our detailed optimization of the rear-panel shield using Geant4 simulation, and describes a demonstration test using our Compton camera.

    AB - After the Japanese nuclear disaster in 2011, large amounts of radioactive isotopes were released and still remain a serious problem in Japan. Consequently, various gamma cameras are being developed to help identify radiation hotspots and ensure effective decontamination operation. The Compton camera utilizes the kinematics of Compton scattering to contract images without using a mechanical collimator, and features a wide field of view. For instance, we have developed a novel Compton camera that features a small size (13×14×15 cm3) and light weight (1.9 kg), but which also achieves high sensitivity thanks to Ce:GAGG scintillators optically coupled wiith MPPC arrays. By definition, in such a Compton camera, gamma rays are expected to scatter in the "scatterer" and then be fully absorbed in the "absorber" (in what is called a forwardscattered event). However, high energy gamma rays often interact with the detector in the opposite direction - initially scattered in the absorber and then absorbed in the scatterer - in what is called a "back-scattered" event. Any contamination of such back-scattered events is known to substantially degrade the quality of gamma-ray images, but determining the order of gamma-ray interaction based solely on energy deposits in the scatterer and absorber is quite difficult. For this reason, we propose a novel yet simple Compton camera design that includes a rear-panel shield (a few mm thick) consisting of W or Pb located just behind the scatterer. Since the energy of scattered gamma rays in back-scattered events is much lower than that in forward-scattered events, we can effectively discriminate and reduce back-scattered events to improve the signal-to-noise ratio in the images. This paper presents our detailed optimization of the rear-panel shield using Geant4 simulation, and describes a demonstration test using our Compton camera.

    KW - Compton imaging

    KW - Models and simulations

    UR - http://www.scopus.com/inward/record.url?scp=84950308334&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84950308334&partnerID=8YFLogxK

    U2 - 10.1088/1748-0221/9/12/C12031

    DO - 10.1088/1748-0221/9/12/C12031

    M3 - Article

    VL - 9

    JO - Journal of Instrumentation

    JF - Journal of Instrumentation

    SN - 1748-0221

    IS - 12

    M1 - C12031

    ER -