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Session: Therapy BLUE RIBBON [Return to Session]

Gamma Imaging Using Hybrid Coded-Aperture and Compton Scatter Imaging

B Montz1*, J Hayward1, C Ramsey1,2, (1) University Of Tennessee, Knoxville,(2) Thompson Cancer Survival Center, Knoxville, TN


SU-I400-BReP-F3-5 (Sunday, 7/10/2022) 4:00 PM - 5:00 PM [Eastern Time (GMT-4)]

Exhibit Hall | Forum 3

Purpose: Coded-aperture imaging and Compton scatter imaging are two techniques that can be used to localize source position. The purpose of this work was to investigate a hybrid approach for gamma imaging that combines the advantages of coded-aperture and Compton scatter imaging. The primary objective of this study was to investigate techniques to combine the data for one coherent image.

Methods: Geant4 simulations were performed for a hand-held Germanium Gamma Imager (GeGI) modified with a coded aperture mask. The mask was created with a specific shadow pattern that will be seen on the detector depending on the angle of incident photons. The detector matrix was compared to the mask at every position with tallies generated based on how many matches occurred between a hole in the mask and counts on the detector. To demine the source location, Compton scatter cones were discretized into individual rays at equal angle intervals along a surface. These individual rays were traced to created geometries in 3D space.

Results: A photon test source was used to successfully combine coded-aperture and Compton scatter images with greatly reduced noise and improved resolution. To improve image quality, the individual rays from the Compton scatter generated cones were weighted depending on their likely probability to have originated from the source. Areas where the coded aperture and Compton images both identify a source will be the most likely origin of the gamma, and thus were weighted higher. These images provide optimal clarity for spatial source location and spectral data that could be used for source identification.

Conclusion: In this study, a novel technique was investigated to combine coded aperture and Compton scatter images for a modified hand-held gamma camera. The combination of these techniques improved spatial resolution.


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