3D silicon detector for imaging of diagnostic and therapeutic nuclear medicine radiotracers with outstanding efficiency and high spatial resolution.

Introduction

This project aims to design, construct, and evaluate a novel instrument for molecular imaging of radioactive nuclides in the human body. The hypothesis is that, by using next-generation silicon sensors to measure each photon interaction and applying kinematic constraints, the incident photon direction can be calculated. Thus, we can remove state-of-the-art mechanical collimators.

Objectives

The main objective of this project is to explore the physical limits of efficiency and spatial resolution and evaluate the concept for this new technology in medical imaging applications.

Expected Improvements

The new instrument should improve detector efficiency by about a factor of one million, reducing examination time from an hour to less than a second. The concept aims to overcome Compton cameras' shortcomings, such as:

• Complicated geometries with low efficiency
• Limitations that have prevented this technique from going beyond an early prototype stage

Sensor Concept

The new sensor concept consists of a massive block of silicon built up from a multitude of sensors, with high resolution in space, energy, and time, including signal shaping and data processing. The system will have orders of magnitude more read-out pixels than ever before in medical imaging.

Challenges

The system design and image reconstruction process are conceptually challenging, addressing several scientific problems at the component level, such as:

1. Pixel charge collection and capacitance
2. Image reconstruction from fragments of event circles
3. Combinatorial problems involved with tracing each event to discern the correct order of interactions
4. Rejecting background events

Long-term Impact

Over a 10–20-year period, the technology could replace the current installed base, leading to significant impacts on adjacent research fields, such as drug development and targeted radionuclide therapy.