Rotating scatter mask for directional radiation detection and imaging
A radiation imaging system images a distributed source of radiation from an unknown direction by rotating a scatter mask around a central axis. The scatter mask has a pixelated outer surface of tangentially oriented, flat geometric surfaces that are spherically varying in radial dimension that corresponds to a discrete amount of attenuation. Rotation position of the scatter mask is tracked as a function of time. Radiation counts from gamma and/or neutron radiation are received from at least one radiation detector that is positioned at or near the central axis. A rotation-angle dependent detector response curve (DRC) is generated based on the received radiation counts. A reconstruction algorithm for distributed radiation source(s) and/or localized source(s) are applied based on the tracked rotation position and prior characterization of the detector response for a given scatter mask. A two-dimensional image with relative orientation and source distribution is generated from the measured DRC.
1. A method for imaging a distributed source of radiation from an unknown direction, the method comprising:
rotating a scatter mask around a central axis, wherein the scatter mask has a pixelated outer surface of tangentially oriented, flat geometric surfaces that are spherically varying in radial dimension from a central position of the central axis by a respective pseudo-random distance that varies between a minimum distance and a maximum distance to provide a particular thickness that corresponds to a discrete amount of attenuation;
tracking rotation position of the scatter mask as a function of time;
receiving radiation counts from at least one radiation detector that is positioned at or near the central axis and that detects one or more of gamma radiation and neutron particle radiation;
generating a rotation-angle dependent detector response curve (DRC) based on the received radiation counts;
applying one or more of: (i) a reconstruction algorithm for one or more distributed radiation source(s); and (ii) one or more localized sources based on the tracked rotation position and prior characterization of the detector response for a given scatter mask; and
generating a two-dimensional image that is associated with a relative orientation and distribution of a source of radiation from the measured DRC.
2. The method of claim 1 , wherein the scatter mask has the pixelated outer surface of tangentially oriented, flat geometric surfaces that are spherically varying in radial dimension from the central position of the central axis by the respective pseudo-random distance that varies between the minimum distance and the maximum distance to provide the particular thickness that corresponds to a discrete amount of attenuation that maximizes the radiation image information encoded as determined through formal optimization of the detector response.
3. The method of claim 1 , wherein applying the reconstruction algorithm comprises applying a regenerative neural network (ReGeNN) algorithm.
4. The method of claim 1 , further comprising creating the scatter mask to have the respective pseudo-random distances that varies between a minimum distance and a maximum distance by creating and solving an eigenvalue problem.
5. A radiation imaging system that images distributed and localized sources of radiation from an unknown direction, the radiation imaging system comprising:
a scatter mask having a pixelated outer surface of tangentially oriented, flat geometric surfaces that are spherically varying in radial dimension from a central position of a central axis by a respective pseudo-random distance that varies between a minimum distance and a maximum distance to provide a particular thickness that corresponds to a discrete amount of attenuation;
at least one radiation detector that is positioned at the central axis and that detects one or more of gamma radiation and neutron particle radiation;
a rotation system to rotate the scatter mask around the central axis; and
a controller that is communicatively coupled to the at least one radiation detector and the rotation system and which:
tracks rotation position of the scatter mask as a function of time,
receives radiation counts from at least one radiation detector that is positioned at or near the central axis and that detects one or more of gamma radiation and neutron particle radiation,
generates a rotation-angle dependent detector response curve (DRC) based on the received radiation counts,
applies one or more of: (i) a reconstruction algorithm for one or more distributed radiation source(s); and (ii) one or more localized sources based on the tracked rotation position and prior characterization of the detector response for the scatter mask, and
generates a two-dimensional image that is associated with a relative orientation and distribution of a source of radiation from the measured DRC.
6. The radiation imaging system of claim 5 , wherein the scatter mask has the pixelated outer surface of tangentially oriented, flat geometric surfaces that are spherically varying in radial dimension from the central position of the central axis by the respective pseudo-random distance that varies between the minimum distance and the maximum distance to provide the particular thickness that corresponds to a discrete amount of attenuation that maximizes the radiation image information encoded as determined through formal optimization of the detector response.
7. The radiation imaging system of claim 5 , wherein the reconstruction algorithm comprises a regenerative neural network (ReGeNN) algorithm.
8. The radiation imaging system of claim 5 , wherein the scatter mask is designed to have the respective pseudo-random distances that varies between the minimum distance and the maximum distance by creating and solving an eigenvalue problem.