Depth-of-interaction enhanced Compton camera using pixelated LYSO(Ce) scintillator arrays and dual-ended SiPMs

Area of Science:

• Medical Physics
• Nuclear Instrumentation
• Radiological Imaging

Background:

• Compton cameras are crucial for imaging in Boron Neutron Capture Therapy (BNCT).
• Accurate spatial resolution is vital for real-time monitoring of boron concentration during BNCT.
• Existing scintillator-based Compton cameras face limitations in position resolution.

Purpose of the Study:

• To enhance the position resolution of a scintillator-based Compton camera using depth-of-interaction (DOI) correction technology.
• To improve spatial resolution in image reconstruction for BNCT applications.
• To evaluate the impact of DOI information on image accuracy.

Main Methods:

• Developed a prototype DOI-based Compton camera using a Cerium-doped Lutetium-Yttrium Oxyorthosilicate (LYSO(Ce)) scintillator array.
• Employed a dual-end readout method to acquire depth information from the scintillator array.
• Simulated the detection of 0.478 MeV gamma photons in BNCT environments using Geant4 and evaluated image reconstruction with Simple Back Projection (SBP) and Maximum Likelihood Expectation Maximization (MLEM) algorithms.

Main Results:

• A linear correlation was established between depth positions and the ratio of dual-end signals, achieving an average DOI resolution of 2.494 mm.
• Incorporating DOI information improved spatial resolution by 6.7 mm (SBP) and 3.1 mm (MLEM) for 0.478 MeV photon images.
• The dual-end readout method effectively provided depth information for improved imaging.

Conclusions:

• Depth-of-interaction (DOI) calibration significantly enhances the quality of prompt gamma photon image reconstruction in BNCT.
• This advancement enables more accurate real-time boron concentration and distribution monitoring.
• The developed DOI-based Compton camera technology contributes to the advancement of BNCT.