MR-guided radiotherapy for liver malignancies

MR guided radiotherapy represents one of the most promising recent technological innovations in the field. The possibility to better visualize therapy volumes, coupled with the innovative online adaptive radiotherapy and motion management approaches, paves the way to more efficient treatment delivery and may be translated in better clinical outcomes both in terms of response and reduced toxicity. The aim of this review is to present the existing evidence about MRgRT applications for liver malignancies, discussing the potential clinical advantages and the current pitfalls of this new technology

Quantitative Analysis of Radiation-Associated Parenchymal Lung Change

Radiation-induced lung damage (RILD) is a common consequence of thoracic radiotherapy (RT). We present here a novel classification of the parenchymal features of RILD. We developed a deep learning algorithm (DLA) to automate the delineation of 5 classes of parenchymal texture of increasing density. 200 scans were used to train and validate the network and the remaining 30 scans were used as a hold-out test set. The DLA automatically labelled the data with Dice Scores of 0.98, 0.43, 0.26, 0.47 and 0.92 for the 5 respective classes. Qualitative evaluation showed that the automated labels were acceptable in over 80% of cases for all tissue classes, and achieved similar ratings to the manual labels. Lung registration was performed and the effect of radiation dose on each tissue class and correlation with respiratory outcomes was assessed. The change in volume of each tissue class over time generated by manual and automated segmentation was calculated. The 5 parenchymal classes showed distinct temporal patterns We quantified the volumetric change in textures after radiotherapy and correlate these with radiotherapy dose and respiratory outcomes. The effect of local dose on tissue class revealed a strong dose-dependent relationship We have developed a novel classification of parenchymal changes associated with RILD that show a convincing dose relationship. The tissue classes are related to both global and local dose metrics, and have a distinct evolution over time. Although less strong, there is a relationship between the radiological texture changes we can measure and respiratory outcomes, particularly the MRC score which directly represents a patient’s functional status. We have demonstrated the potential of using our approach to analyse and understand the morphological and functional evolution of RILD in greater detail than previously possible

Deep learning in medical imaging and radiation therapy

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146980/1/mp13264_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146980/2/mp13264.pd

Nuclear Imaging and Therapy:Towards a Personalized Approach in HCC and NET

This thesis explores new applications of nuclear imaging and therapy in patients with hepatocellular carcinoma (HCC) and neuroendocrine tumors (NET). These diseases are often detected late, making curative therapy not always possible. Developments in positron emission tomography (PET) and radionuclide therapy have led to new nuclear agents. The aim of this thesis is to provide insight into several new applications of current and new tracers in the diagnosis and treatment of HCC and NET.One of the investigated tracers is 18F-DOPA, which is currently used for NET tumors that are negative on 68Ga-labeled somatostatin analog (SSA) PET scans. Our study confirms the equivalent detection of 18F-DOPA in tumor detection compared to 68Ga-SSAs. Selective internal radiation therapy (SIRT) uses yttrium-90 radioactive resin spheres that are intravascularly injected into the liver. Higher than usual dosages (>120 Gy) appear to lead to better results in tumor reduction and the effects not only seem to be greater but also longer lasting.Furthermore, we demonstrated that 11C-Choline and 18F-FDG together find more tumors that are relevant for clinical decision-making in patients suspected of HCC recurrence. The thesis also offers two prospective study protocols, namely a comparison of 68Ga-DOTA-TOC with the new somatostatin tracer 18F-SiTATE in NET and a comparison of ablation with SIRT as a bridge strategy in liver transplantation. These results suggest that broader use of 18F-DOPA in PET diagnosis of NET is possible and that higher tumor-targeted dosages in SIRT can lead to better treatment