Silicon-based 3D beta ray radiopharmaceutical trackers: a Monte Carlo computational study

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiochemistry

Background:

• Accurate radiotracer distribution quantification is crucial for radiopharmaceutical development and dose planning.
• Conventional digital autoradiography (DAR) is limited to 2D imaging of thin samples, hindering volumetric analysis.
• Existing methods require extensive sample preparation, limiting their utility for intact tissue analysis.

Purpose of the Study:

• To introduce a novel three-dimensional digital autoradiography (3D DAR) imaging modality.
• To enable imaging of thick tissue samples intact, preserving volumetric information and reducing acquisition time.
• To assess the spatial resolution and sensitivity of the proposed 3D DAR system for preclinical radiopharmaceutical therapy (RPT) development.

Main Methods:

• Developed a 3D DAR system utilizing multiple layers of ultra-thin silicon detectors to track charged particles.
• Employed Monte Carlo simulations to model detector configuration and quantify performance across various energy levels and depths.
• Estimated particle trajectories by connecting response lines from stacked detectors for each event.

Main Results:

• Demonstrated tens of micron spatial resolution and approximately 30% coincidence sensitivity.
• Achieved a spatial resolution of approximately 27 µm at 30 µm depth, a threefold improvement over 2D methods.
• Confirmed the capability of 3D DAR to provide volumetric source information within thick tissue samples.

Conclusions:

• The proposed 3D DAR system offers potential for sub-tissue scale activity mapping in thicker samples than conventional DAR.
• This technology facilitates a more detailed understanding of radiopharmaceutical distribution in the tumor microenvironment.
• 3D DAR significantly enhances ex-vivo tissue analysis for preclinical radiopharmaceutical therapy development.