‘Saving the brain’

Radiotherapy-induced brain injury can clinically manifest as cognitive decline and neurobehavioral impairment and is considered irreversible in the chronic phase, affecting patients’ quality of life [1][2]. The suspected mechanisms of cognitive decline seem to be complex and probably triggered by early microvascular damage causing disruptions in blood flow and improper blood-brain barrier function, loss and dysfunction of oligodendrocytes, damage and dysfunction of astrocytes, delayed neurogenesis, inflammation, neurodegeneration and microanatomical abnormalities and therefore, neuronal dysfunction [3]. Cognitive decline occurs within months or years after radiotherapy [1-3]. So far, no validated imaging tools are available for assessing the risks of acute and/or chronic brain damage caused by radiotherapy. Several MRI techniques, such as Susceptibility Weighted Imaging (SWI), Quantitative Susceptibility Mapping (QSM), vessel architectural imaging (VAI), Arterial Spin Labelling (ASL), Synthetic MRI (synMRI) and Diffusion Kurtosis Imaging (DKI) have the potential to visualize microvascular changes and white matter changes, especially when combining findings of several individual approaches. Furthermore, metabolic brain changes, neuroinflammation and neurodegeneration can be monitored by respectively [18F]FDG PET, [11C]UCB-J PET and [11C]PK11195 PET.
Therefore, in this pilot study we want to look at different aspects of radiation damage, including effects on microvasculature, blood-brain barrier function and white matter changes. We hypothesize that combining these different imaging modalities (MRI and PET) with advanced post-processing will increase the understanding of in vivo changes resulting from radiotherapy-induced injury and will allow the detection of radiotherapy-induced brain injury at an early stages. We also hypothesize that early detection of changes (or lack thereof) will be predictive of (later) cognitive outcome assessed by neurocognitive function test.

In this pilot study we want to look at different aspects of radiation damage, including effects on microvasculature, blood-brain barrier function and white matter changes. We hypothesize that combining these different imaging modalities (MRI and PET) with advanced post-processing will increase the understanding of in vivo changes resulting from radiotherapy-induced injury and will allow the detection of radiotherapy-induced brain injury at an early stages. We also hypothesize that early detection of changes (or lack thereof) will be predictive of (later) cognitive outcome assessed by neurocognitive function test.
Primary Objective: Is detection of the early brain changes, including microvascular and white matter radiotherapy-induced changes, possible already during radiotherapy treatment by means of combining novel MRI and PET techniques and post-processing methods in patients treated for head and neck tumours.

The study will consist of 5 visits:
- baseline visit within 2 weeks before the start of radiotherapy (clinical-research visit combined)
- 2 weeks after the beginning of radiotherapy (research visit only)
- directly after the end of radiotherapy (research visit only)
- 3 months after the end of radiotherapy (clinical-research visit combined)
- 1 year after the end of radiotherapy (clinical-research visit combined)

not applicable