Ultracompact Compton camera for innovative gamma-ray imaging

Kataoka, J.; Kishimoto, A.; Taya, T.; Mochizuki, Seibu; Tagawa, Leo; Koide, A.; Sueoka, Koki; Morita, Hayato; Maruhashi, Takuya; Fujieda, Kazuya; Kurihara, Takuya; Arimoto, M.; Okochi, Hiroshi; Katsumi, Naoya; Kinno, S.; Matsunaga, Keiko; Ikeda, Hayato; Shimosegawa, Eku; Hatazawa, Jun; Ohsuka, Shinji; Toshito, T.; Kimura, Mitsuhiro; Nagao, Yuto; Yamaguchi, Mitsutaka; Kurita, Keisuke; Kawachi, Naoki

doi:10.1016/j.nima.2017.09.048

Cited by 19 publications

(10 citation statements)

References 18 publications

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“…In the Fukushima field, the protocol successfully visualized the extended gamma radiation source with surface dose rates of much less than 1 μSv/h, which is an order of magnitude lower than that in a recent report 25,26 . Our Compton camera system was found to be capable of operating stably and robustly for outdoor measurement.…”

Section: Discussionmentioning

confidence: 72%

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

Muraishi¹,

Enomoto²,

Kagaya³

et al. 2020

JoVE

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We present experimental protocols for visualizing various low-level gamma radiation sources in the ambient environment. Experiments were conducted by using a low-cost, high-sensitivity, omnidirectional, gamma-ray imaging Compton camera. In the laboratory, the position of a sub-MeV gamma radiation source such as 137 Cs can easily be monitored via omnidirectional gamma-ray imaging obtained by the Compton camera. In contrast, a stationary, wall-mounted dose rate monitor cannot always successfully monitor such a source. Furthermore, we successfully demonstrated the possibility of visualizing the radioactivity movement in the environment, for example, the movement of a patient injected with 18 F-fluorodeoxyglucose (18 F-FDG) in a nuclear medicine facility. In the Fukushima field, we easily obtained omnidirectional gamma-ray images concerned with the distribution on the ground of low-level radioactive contamination by radioactive cesium released by the Fukushima Daiichi nuclear power plant accident in 2011. We demonstrate clear advantages of using our procedure with this camera to visualize gammaray sources. Our protocols can further be used to discover low-level gamma radiation sources, in place of stationary dose rate monitors and/or portable survey meters used conventionally. Video Link The video component of this article can be found at https://www.jove.com/video/60463/ Recently, we have proposed and developed a low-cost, high-sensitivity, omnidirectional gamma-ray imaging Compton camera 18 , based on a twofold coincidence within a number of independent scintillators that act as either scatterers or absorbers 19. The aim of this technique is to easily achieve high detection efficiency with an angular resolution s of ~10 degrees or less, which is adequate for an environmental monitor. This is accomplished through the application of an image-sharpening technique 18,20 based on the filtered back-projection algorithm, which applies a convolution filter used in image reconstruction for computed tomography to the Compton reconstruction. Furthermore, the detection efficiency, angular resolution and dynamic range of the detector can be easily optimized when the type, size and arrangement of scintillators are coordinated in accordance with a particular purpose, such as usage in environments emitting elevated radioactivity 21,22. In this study, we present experimental protocols for various trials for visualizing low-level gamma-ray radiation sources using this omnidirectional Compton camera technique in a radioisotope (RI) facility, a positron emission tomography (PET) facility and the Fukushima field. We prepared

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Section: Discussionmentioning

confidence: 72%

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

Muraishi¹,

Enomoto²,

Kagaya³

et al. 2020

JoVE

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“…Compton imaging is applied to range estimation in particle therapy [37][38][39] and to environmental measurements [40][41][42]. In these applications, the scattered noise component is larger than that in nuclear medicine imaging, because the number of high-energy radiations significantly exceeds that of signals radiations.…”

Section: Discussionmentioning

confidence: 99%

Crosstalk Reduction Using a Dual Energy Window Scatter Correction in Compton Imaging

Sakai

Parajuli

Kubota

et al. 2020

Sensors

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Compton cameras can simultaneously detect multi-isotopes; however, when simultaneous imaging is performed, crosstalk artifacts appear on the images obtained using a low-energy window. In conventional single-photon emission computed tomography, a dual energy window (DEW) subtraction method is used to reduce crosstalk. This study aimed to evaluate the effectiveness of employing the DEW technique to reduce crosstalk artifacts in Compton images obtained using low-energy windows. To this end, in this study, we compared reconstructed images obtained using either a photo-peak window or a scatter window by performing image subtraction based on the differences between the two images. Simulation calculations were performed to obtain the list data for the Compton camera using a 171 and a 511 keV point source. In the images reconstructed using these data, crosstalk artifacts were clearly observed in the images obtained using a 171 keV photo-peak energy window. In the images obtained using a scatter window (176–186 keV), only crosstalk artifacts were visible. The DEW method could eliminate the influence of high-energy sources on the images obtained with a photo-peak window, thereby improving quantitative capability. This was also observed when the DEW method was used on experimentally obtained images.

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“…The camera consisted of 20×20×5 arrays of Ce:GAGG pixels as a scatterer, whereas 20×20×10 arrays of Ce:GAGG pixels were used as an absorber. Unlike other Compton cameras developed in our group 33,[48][49][50] , we used two multi-anode PMTs (MAPMTs; Hamamatsu H12700A) of 8×8 anodes to readout the scintillation light from the right/left ends of the scintillator arrays. This is because the radiation tolerance of the MPPC is uncertain, particularly for damage caused by fast neutrons in proton beam facilities.…”

Section: D-pscc For Prompt Gamma-ray Imagingmentioning

confidence: 99%

Precision imaging of 4.4 MeV gamma rays using a 3-D position sensitive Compton camera

Koide

Kataoka

Masuda

et al. 2018

Sci Rep

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Imaging of nuclear gamma-ray lines in the 1–10 MeV range is far from being established in both medical and physical applications. In proton therapy, 4.4 MeV gamma rays are emitted from the excited nucleus of either 12C* or 11B* and are considered good indicators of dose delivery and/or range verification. Further, in gamma-ray astronomy, 4.4 MeV gamma rays are produced by cosmic ray interactions in the interstellar medium, and can thus be used to probe nucleothynthesis in the universe. In this paper, we present a high-precision image of 4.4 MeV gamma rays taken by newly developed 3-D position sensitive Compton camera (3D-PSCC). To mimic the situation in proton therapy, we first irradiated water, PMMA and Ca(OH)2 with a 70 MeV proton beam, then we identified various nuclear lines with the HPGe detector. The 4.4 MeV gamma rays constitute a broad peak, including single and double escape peaks. Thus, by setting an energy window of 3D-PSCC from 3 to 5 MeV, we show that a gamma ray image sharply concentrates near the Bragg peak, as expected from the minimum energy threshold and sharp peak profile in the cross section of 12C(p,p)12C*.

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Ultracompact Compton camera for innovative gamma-ray imaging

Cited by 19 publications

References 18 publications

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

Visualization of Low-Level Gamma Radiation Sources Using a Low-Cost, High-Sensitivity, Omnidirectional Compton Camera

Crosstalk Reduction Using a Dual Energy Window Scatter Correction in Compton Imaging

Precision imaging of 4.4 MeV gamma rays using a 3-D position sensitive Compton camera

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