Creation of an anisotropic planned target volume in brain radiotherapy

Fabien RECH

Glioblastoma are the most common primitive malignant brain tumor in adults. Their treatment rely on
surgery, chemotherapy and radiotherapy.

Tumor cells migrate along the white matter tract so that their microscopic diffusion around the radiological
identified tumor is anisotropic.

However brain radiotherapy is performed isotropically, that is with an identical margin around the
radiologically identified tumor (2 cm). This volume is called PTV (planned target volume) and is defined prior
to radiotherapy

Our objective is here to take account for the cells migration along the whitte matter tract and modulate this
PTV by considering the distance in terms of length and fiber orientation instead of euclidian distance. The
aim is to obtain an anisotropic PTV to increase irradiation in area of major cells migrations and to decrease
irradiation in area of less cells migratrion.

It will be necessary to create a software taking in entry DICOM RT files, extract the GTV (gross tumor
volume), calculate the anisotropic PTV from a given tractogramm (coming from DTI atlas) and insert this new
PTV in DICOM files to perform a radiotherapy planning.

brain radiotherapy, white matter, MRI

6 months

Biology, Signals and Systems in Cancer and Neuroscience

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