Physiological MRI for Precision Radiotherapy IDH-wildtype Glioblastoma

Volume and location analysis of physiological and standard CTV

After surgery, a key step in treatment of patients diagnosed with glioblastoma (high grade
 brain tumour) is radiotherapy. The ideal clinical target volume (CTV) for radiotherapy
 treatment planning includes all tumour cells remaining after surgery. Currently, the GTV is
 delineated on conventional imaging techniques that are only visualizing macroscale structural
 changes due to the presence of a large number of tumour cells. After delineating these
 visible macroscale changes, the GTV is expanded in all directions with 1.5cm into visibly
 healthy tissue to account for microscale tumour invasion. This standard CTV therefore also
 contains healthy tissue that should not be receiving radiation, causing side effects of
 treatment, hereby reducing quality of life for patients.
 
 Generating a physiological CTV, in which microscale invasion of tumour cells is taken into
 account specifically whilst sparing healthy tissue that is not in need of radiation, is
 essential for reducing side effects of radiotherapy. To do so, visualisation is necessary of
 physiological processes of tumour cells, which are present before macroscale structural
 changes occur. State-of-the-art MRI techniques are now in use at the Erasmus MC that can
 assess these physiological processes, including oxygenation status and cell proliferation.
 
 We aim to generate proof-of-concept of using a physiological CTV for radiotherapy treatment
 planning for patients with brain tumours. By extending the clinical standard MRI session used
 for radiotherapy planning in 10 patients diagnosed with glioblastoma with advanced MRI
 techniques that assess oxygenation status and cell proliferation, we will generate the
 physiological CTV including this information and illustrate that it is more precise in
 capturing microscale tumour invasion. This proof-of-principle work will be used to obtain
 external funding to perform the much needed, and the first of its kind globally, clinical
 trial to show the benefit of a physiological CTV for radiotherapy treatment planning in
 glioblastoma.