A Pilot Study to monitor changes in Rectum Carcinoma during Radiotherapy with multi-parametric MRI

An integrated MRI-linear accelerator (MRL) would be able to use Magnetic
resonance imaging (MRI) images for pre-treatment setup of radiotherapy
patients. While we have substantial information on the geometric changes in the
clinical target volume (CTV) of rectum carcinoma patients using repeat-CT data,
not much data is available on the (geometric and functional) behavior of the
gross tumor volume (GTV) during treatment. Due to the excellent soft tissue
contrast of Magnetic Resonance Imaging (MRI), and the possibilities of
functional MRI, MRI exams during the course of treatment would make this
information available. The MRL therefore opens up the possibility to reduce
uncertainties in the shape and position of the GTV and to adapt the treatment
to the functional response of the GTV to the treatment.

This study aims to be a pilot study for the treatment of rectum carcinoma on
the MRL. A dataset will be collected which allows for an estimation of the
anatomical and geometrical variation of the GTV and of the variation of the
functional response of the GTV on the treatment. This knowledge is essentail
for the investigation of the full potential of treating rectum carcinoma on the
MRL. With the dataset a first estimate of the clinical opportunities of such
treating can be derived, which would serve as the basis for further
investigations.

The primary objective of the study is to establish an estimate of the
anatomical variation (position, shape, size) and the functional MR parameters
of the GTV during radiotherapy treatment.

The study is an observational pilot study in which 2 x 6 patients (6 male, 6
female) with proven adenocarcinoma in the rectum, receiving radiotherapy of 25
x 2 Gy will be included.
Each participating patient will receive weekly an additional MRI exam, before
or after the radiotherapy fraction of that day.Resulting in a total 5
additional exams. The MRI exams will include a combination of anatomical and
functional MRI scans (T1-Weighted, T2-Weighted, Diffusion-Weighted Imaging,
Dynamic Contrast-Enhanced MRI).

As part of this research there are five additional MRI scans. Because the first
MRI scan made on the same day as the first radiation fraction it does not need
a separate baseline MRI scan.

Patients undergo the standard MRI examination several times. In the standard
exam, 15 ml of contrast DOTAREM (Gadoteric acid 0.5M) is administered i.v..
There are no side effects known of this agent. However, an allergic reaction
can not be excluded. For patients who have undergone the standard examination
as part of their treatment, the repetition of this exam presents a negligible
risk.