GN-Vision is a novel dual γ -ray and neutron imaging system, which aims at simultaneously obtaining information about the spatial origin of γ -ray and neutron sources. The proposed device is based on two position sensitive detection planes and exploits the Compton imaging technique for the imaging of γ -rays. In addition, spatial distributions of slow- and thermal-neutron sources ( < 100 eV) are reconstructed by using a passive neutron pin-hole collimator attached to the ﬁrst detection plane. The proposed gamma-neutron imaging device could be of interest for ion-beam range veriﬁcation in hadron therapy and in nuclear safety and security applications. The two main advantages of this imaging system are its high e ﬃ ciency and portability, making it well suited for clinical beam-lines and nuclear applications were compactness and real-time imaging is important. This work presents the working principle and conceptual design of the GN-Vision system based on Monte Carlo simulations and explores its simultaneous γ -ray and neutron detection and imaging capabilities for a realistic case of a security inspection where a 252 Cf source is hidden in a neutron moderating container.

Simultaneous Gamma-Neutron Vision device: a portable and versatile tool for nuclear inspections

11 We report on a combined in-beam PET and prompt-gamma Compton imaging system aimed at ion-range veriﬁcation in proton-therapy treatments. A proof-of-concept experiment was carried out at the radiobiology beam line of the CNA cyclotron facility using a set of two synchronous Compton imagers and different target materials. The time structure of the 18 MeV proton beam was shaped with a series of beam-on and beam-off intervals, thereby mimicking a pulsed proton beam on a long time scale. During beam-on Compton imaging was performed utilizing the high energy γ -rays promptly emitted from the nuclear reactions in the target. In the course of the beam-off intervals in-situ positron-emission tomography was accomplished with the same imagers using the β + decay of short-lived activated nuclei. The targets used were stacks of different materials covering also various proton ranges and energies. The experimental results obtained in this work are compared with a Monte Carlo model of the experimental setup. The results demonstrate the possibility to combine both imaging techniques in a concomitant way, where high-efﬁciency Compton imaging is complemented with the high spatial accuracy of PET. Empowered by these results we discuss a new methodology for enhanced accuracy and real-time ion-range monitoring. We suggest that a pulsed beam with a suitable duty cycle, in conjunction with in-situ Compton- and PET-imaging may help to attain both real-time and high-accuracy range monitoring.

In-beam PET and Compton imaging for enhanced accuracy proton-range verification

Abstract We report on a hybrid in-beam PET and prompt-gamma Compton imaging system aimed at quasi real-time ion-range verification in proton-therapy treatments. Proof-of-concept experiments were carried out at the radiobiology beam line of the CNA cyclotron facility using a set of two synchronous Compton imagers and different target materials. The time structure of the 18 MeV proton beam was shaped with a series of beam-on and beam-off intervals, thereby mimicking a pulsed proton beam on a long time scale. During beam-on intervals, Compton imaging was performed utilizing the high energy $$\gamma$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> -rays promptly emitted from the nuclear reactions occurring in the targets. In the course of the beam-off intervals in situ positron-emission tomography was accomplished with the same imagers using the $$\beta ^{+}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>β</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> decay of activated nuclei. The targets used were stacks of different materials covering also various proton ranges and energies. A systematic study on the performance of these two complementary imaging techniques is reported and the experimental results interpreted on the basis of Monte Carlo calculations. The results demonstrate the possibility to combine both imaging techniques in a concomitant way, where high-efficiency prompt-gamma imaging is complemented with the high spatial accuracy of PET. Empowered by these results we suggest that a pulsed beam with a suitable duty cycle, in conjunction with in situ Compton- and PET-imaging may help to attain complementary information and quasi real-time range monitoring with high accuracy. 

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Maria del Carmen Jim'enez-Ramos

Papers

In-beam PET and Compton imaging for enhanced accuracy proton-range verification

Hybrid in-beam PET- and Compton prompt-gamma imaging aimed at enhanced proton-range verification