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Monte Carlo Simulation based Performance Evaluation of Heterostructure Radiation Detector Materials for Time of Flight-Positron Emission Tomography Imaging

Computer guided evaluation and optimization of the performance of heterostructure radiation detectors.

Student

Phil Krause

Supervisor

Dr Greg Bizarri

Dr Iva Chianella

 

Project aim

Computer guided evaluation and optimization of the performance of heterostructure radiation detectors

Project Objectives

  1. Develop a Monte Carlo simulation to quantify the scintillating performance (e.g., energy absorbed, energy partition, event to event fluctuation) of complex heterostructure materials.
  2. Validate the Monte Carlo simulation against measured scintillation performance of real heterostructure detectors.
  3. Survey and understand the impact of the heterostructure geometry and the material choices on the overall scintillation performance.
  4. Optimise heterostructure geometry and material choice to maximise the scintillation performance of a heterostructure ToF-PET pixel.

Project Outline

Positron Emission Tomography is a well-established technique used to look inside the body. It is used for the early diagnosis and management of cancer, cardiovascular disease, Alzheimer disease, inflammation, and immunology.

Despite the clear acceptance of PET, there is still a wide gap between current performance and clinical end user’s needs.  This inability to match application needs to detector properties is deeply rooted in the historical approach of using a unique lanthanide doped material as the sole energy conversion medium.  The concept of the heterostructure radiation detector, a single crystal body in which an ultra-fast component is embedded, has been demonstrated as a possible avenue to bypass the performance limitations of the monolithic single crystal approach. Enabling both ultra-fast and short attenuation length detector materials is the main gateway to substantial advancement of ToF-PET technology, and ultimately enabling direct ToF imaging, the holy grail of nuclear medical imaging.

The project aims to address the limitations of the single detector material approach by developing a novel family of radiation sensing heterostructures - in which multiple materials work in synergy to achieve unparalleled performance - and in turn enable the production of ultra-fast and short attenuation length alternatives to the currently inherently limited ToF-PET detectors. In this approach, one material remains responsible for the short attenuation length (absorber), while the other for the ultra-fast response time (emitter).  This is a very challenging project pushing the boundaries of what is possible in the ultra-precision field and material science. The three primary and scientifically interconnected areas for enabling the development of heterostructure detector materials are: 1) engineering and optimization of higher efficiency ultra-fast scintillators; 2) development of cost-effective micro-machining processes of hard and brittle single crystals and 3) optimization of surface functionalisation for improved light management.

Simulation work is the backbone of the project. It focuses on providing the refinement of the layout in term of material choice, design for the precision machining of the absorber and the performance requirement of the fast scintillator.

The combination of single crystals, nanocomposites and thin film weaved together into a heterostructure could revolutionise the detector industry, in a similar way to how the semi-conductor industry revolutionised the electronic industry.

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