Development of novel gamma detector arrays for industrial and medical applications

Hampel, Dawid M. (2024). Development of novel gamma detector arrays for industrial and medical applications. University of Birmingham. Ph.D.

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Abstract

Positron emission particle tracking (PEPT) is a technique directly developed from positron emission tomography (PET) where the position of a positron-emitting radiotracer is calculated from the lines-of-response (LORs) of a PET scanner. First developed at the University of Birmingham in the 1980s to study fluid flow in heavy industrial machinery, the technique has been applied to study the behaviour of systems used in food, recycling, pharmaceutical, and medical industries, to name a few. From studying flow patterns to breakup of particles, data acquired through PEPT has been used to validate simulation models and help uncover the mysteries of systems for which no simulation model exists.

From chemical engineers to mathematicians, PEPT is a technique that brings many areas of study together. However, while most PEPT users pay great attention to the tracking algorithms, interpretation of the positional data, and comparison of data to their models and expectations, very few pay attention to the machines and physics that make PEPT work. Failure to understand the fundamental limits of the positron scanners used for PEPT has led to overestimated expectations and noisy or low amounts of data for proper position calculations.

This thesis begins forth a detailed discussion of the history of PET and PEPT in order to understand the fundamental physics limitations and design choices of the scanner technologies --- in particular the technical aspects of all BGO-based ECAT series PET scanners. This information has been used for the development of novel, dedicated PEPT systems which is the main focus of this thesis work. The systems are built from parts of deprecated medical machines, pushing the technologies to their absolute limits. The most advanced, dedicated PEPT system to date, SuperPEPT, has exceeded expectations. It has displayed superior sensitivity, a very high 2.1 MHz data rate, a large 40.00 cm diameter and 53.50 cm long field-of-view (FOV), and a 5 mm PEPT spatial resolution providing the best tracking accuracy available in PEPT. Furthermore, the expansion of the Large Modular Array (LaMA) for PEPT made it the only reconfigurable PEPT system of such scale which can accommodate uniquely shaped industrial systems through the largest FOV of any PEPT system to date.

Through the use of non-destructive design verification methods like PEPT, large datasets of verification data can be obtained for simulation and design verification. SuperPEPT's extreme sensitivity and large data rate further expand PEPT into tracking of sub-millimetre particles with lesser amounts of activity than possible with previous scanners at the Positron Imaging Centre (PIC). Furthermore, LaMA PEPT has already shown its ability to adapt and meet the demands of larger lab-scale industrial appliances. Its use to verify the behaviour of the FLSmith CoarseAIR™ fluidised bed flotation cell (FBFC) had show its ability to acquire data over an FOV that is over 2 m tall. With these two systems currently available on top of the other equipment at the PIC, the different possibilities to study industrial equipment have never before been so flexible.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):