Nuclear imaging: from the development of new production methods of terbium theragnostic isotopes, to the exploration of positron emission tomography for industrial applications

Trinder, Rebeckah Rachael ORCID: 0000-0002-5993-8867 (2022). Nuclear imaging: from the development of new production methods of terbium theragnostic isotopes, to the exploration of positron emission tomography for industrial applications. University of Birmingham. Ph.D.

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Abstract

Nuclear imaging has a wide range of applications in both medicine and in industry, such as diagnostic imaging in the former. The emerging field of theragnostics aims to use the two halves of nuclear medicine (therapy and diagnostic imaging) to tailor cancer treatments to each specific case. For optimal theragnostic treatment different isotopes of the same element should be used for the diagnostic imaging and therapy. A good candidate is terbium which has four medically-promising isotopes 149Tb and 161Tb for cancer therapy, and 152Tb and 155Tb for PET and SPECT nuclear imaging, respectively. The work discussed here looks at the production of the nuclear imaging isotopes 152Tb and 155Tb from α beams on Eu targets. To develop this new α+Eu production route, cross-sections of relevant nuclear reactions are needed. No previous nuclear reaction cross-sections for α+Eu have been measured for the production of these medical Tb isotopes. Therefore, the cross-section for the production of 152Tb and 155Tb and the contaminant Tb isotopes and isomers 151Tb, 152Tbm1, 153Tb, 154Tb, 154Tbm1, 154Tbm2 and 156Tb from the α+Eu reactions were measured and are reported in this work. To enable this study, a method of measuring nuclear reaction cross-sections at the Birmingham Cyclotron Facility was developed and the details of each step are given in this thesis. In the process of measuring the cross-sections for each Tb isotope and isomeric state, new more precise half-life values for PET 152Tb and SPECT 155Tb isotopes were also measured. These are 17.07(7) hours and 5.25(1) days, respectively. Updated half-life values for the contaminant isotopes and isomeric states: 152Tbm1, 153Tb, 154Tbm1 and 154Tbm2 were also measured, and found to be 4.22(2) minutes, 2.291(6) days 9.43(4) hours and 23.58(15) hours, respectively. Details on how these quantities were obtained, along with a comparison to previous half-life measurements are also discussed. Cross-section calculations using the reaction code TALYS are also presented and compared to the experimental data.

Nuclear imaging can be performed using PET tracers and scanners. Although commonly used for medical applications, the work discussed in the latter part of this thesis details the development of novel techniques of using a former medical GE Discovery ST PET/CT scanner to explore the breadth of information that can be extracted from PET images taken of industrial machinery. Industrial PET imaging could provide alternative gas and liquid flow information in machinery that would not be obtainable using solid tracers in PEPT (a method of nuclear imaging which is currently used for industrial applications). Measuring the flow of gases and studying chemical reactions inside devices such as carbon absorbers and catalytic converters would be a desirable goal for industrial PET imaging, however, preliminary investigations were needed to develop the imaging techniques and analysis required. The first steps toward this goal were developed and are discussed in this work. Both qualitative and quantitative information about fluid flow through pipes with CALGAVIN inserts were measured. The final results included extracting dimensional information about the fluid flow and developing a technique using the voxel intensity data to measure residence time.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):