Optimization of MRI scan protocols for radiotherapy and hyperthermia treatment planning

Advanced tumors in the head and neck region are normally treated with
radiotherapy, sometimes with the addition of chemotherapy. This treatment is
not always successful and side-effects are severe. After treatment, patients
suffer from losing saliva production and swallowing functionality.
Hyperthermia, rising tissue temperature to 39-45°C, has shown to improve
radiotherapy and chemotherapy for various tumors and different tumor-sites
while the increase in side effects is negligible. With the recently developed
HYPERcollar, heating in the head and neck region deeper than 4cm from the skin
became possible.

The HYPERcollar, consists of a circular array of twelve antennas with
independent control. Optimum use of this arrangement requires patient-specific
treatment planning based on detailed computer simulations. Such simulations
require a full 3D tissue distribution in which about 15 different tissues are
distinguished. At this moment, computed tomography (CT) scans are used for
generating this patient model.

CT scans, however, fail to show tissue transitions between soft-tissues that
are highly relevant for electromagnetic simulations. Magnetic resonance imaging
(MRI) is a safe, reproducible, non-invasive, technique that can be used to show
human tissue, with a focus on soft-tissue interfaces.

To investigate if creating 3D patient models can be improved and accelerated by
using both CT and MRI data we need to obtain such data from patients. This is
important because tissue distributions can be influenced severely depending on
size and location of the tumor. Further, we need to assess if the MRI must be
taken in radiotherapy position (with head support and mask) or in the, more
comfortable, anatomic position suffices.

The main goal of this study is to obtain MRI scans for investigating new
algorithms for improvement and acceleration of patient model generation for
radiotherapy and hyperthermia treatment planning.

Patients eligible for radiotherapy treatment of a tumor in the head and neck
region are selected. After informed consent, patients will receive two MRI
scans in addition to their CT for radiotherapy treatment planning. The two MRI
scans with the patient in two different positions are required to investigate
the influence of variations on the outcome and robustness of the segmentation
algorithms.

With the screening for contraindications, no objective risks are inherent to
the use of the MRI and contrast.