Page 24 - Quantitative Imaging of Small Tumours with Positron Emission Tomography

Aim and outline of the thesis 1 The clinical use of quantitative assessment of PET images in oncology is maturing and merging into clinical practice. Therefore, it is crucial to know if and how small tumours can be accurately and reliably assessed using quantitative PET analysis. Moreover, the clinical value of these analyses needs to be defined. In the present thesis we aim to perform technical validation of small tumour quantitative PET imaging and investigate its clinical application. In Part 1 (chapter 2-4) of this thesis we focus on methodological aspects of quantitative PET imaging of small tumours, specifically investigating the performance of PVC. In Part 2 (chapter 5-8) we explore the clinical benefit of quantitative assessment of small tumours on PET and the impact of applying PVC. In Chapter 2 we investigate the accuracy and precision of several PVC methods, in combination with several different methods for tumour delineation on PET in [18F]FDG and [18F]FCH PET-CT. In Chapter 3 we assess how parametric PVC affects pharmacokinetic modelling on dynamic [18F]FLT PET-CT and validation of simplified parameters in NSCLC patients undergoing systemic treatment. Chapter 4 focusses on the influence and interplay of image noise and PVC on the repeatability of quantitative tumour assessment on [18F]FDHT PET- CT in metastatic PCa patients. In Chapter 5 we assess the repeatability of [18F] DCFPyL PET-CT in metastatic PCa patients and evaluate the impact of PVC. In Chapter 6 we perform machine learning-based analysis of [18F]DCFPyL PET-CT radiomics for risk-stratification of primary PCa patients, and assess the impact of PVC and tumour delineation methods. In Chapter 7 we systematically review and perform meta-analysis on the clinical application of PVC in PET studies in oncology. In Chapter 8 we evaluate whether PVC can improve prediction of outcome after stereotactic body radiotherapy (SBRT) for oligometastatic prostate cancer using [18F]FCH PET-CT. In Chapter 9 we discuss methodological aspects of quantification of [18F]DCFPyL and [18F]FDHT in prostate cancer, and provide clinical illustration of its use in response assessment. In Chapter 10 we benchmark the predictive value of the [18F]DCFPyL radiomics analysis from Chapter 6 against methods used in clinical practice. Lastly, a summarizing discussion of findings is presented in Chapter 11. General introduction 23