Quantification of bowel motility in gynecological cancer patients during radiotherapy using MRI.

To reduce the risk of bowel toxicity in gynecological malignancies patients
undergoing curative radiotherapy, irradiation of organs at risk (OARs) (i.e.
bowel and bladder ) should be minimized. Gynecological malignancies are
standardly irradiated with high radiation doses, typically delivered by
external beam radiotherapy (EBRT) sessions followed by one or two brachytherapy
(BT) sessions. During the treatment course, patients undergo three or four
magnetic resonance imaging (MRI) scans, which are used for treatment planning.
Based on the delineated tumor and OARs, radiation doses are calculated.
However, variation in bowel position due to bowel motility can result in
unpredictable dose distributions with the risk of exceeding the planned doses.
Deviating from the planned dose may lead to increased risk of severe acute and
late/chronic bowel toxicity. Therefore, bowel motility during radiation should
ideally be taken in account and integrated in the treatment planning. However,
until to date, methods for assessing bowel motility during radiotherapy
treatment are non-existing.

In this pilot study, we aim to quantify bowel motility in gynecological cancer
patients undergoing radiotherapy using MRI. Furthermore, to gain more
understanding about bowel motility in this patient group, we would also like to
assess variation in bowel motility induced by several factors (for example
radiation, patient preparation for brachytherapy and previous major abdominal
surgery). MRI provides 3D images with good quality for accurate motility
assessment. In addition, MRI is a non-invasive modality with no radiation
burden making it the best tool for this pilot study.

* The primary objective is:
the quantification of bowel motility in gynecological cancer patients
undergoing radiotherapy using MRI.

* The Secondary objectives are:
- assessment of bowel motility variation within a patient during
their treatment course.
- assessment of bowel motility variation between patients with a
focus on changes of bowel motility associated with major abdominal
surgery.

This pilot study will be conducted in ten gynecological cancer patients
undergoing definitive radiotherapy with curative intent. In the standard care,
patients undergo 3 to 4 MRI scans at different time points (prior to and during
radiotherapy). To quantify bowel motility, an extra MRI sequence (10 min) will
be added to the standard MRI scans (45 min). From the obtained MRI scans, bowel
motility will be quantified. Bowel motility will be expressed as bowel
displacement in three orthogonal directions. The motility between the MRI scans
will be compared within and between patient in order to assess the effect of
radiation, patient preparation and abdominal surgery in the past on bowel
motility.

The additional motility MRI sequence will be added to each standard MRI scans
(45 min, three to four times). Each motility scan will take about 10 minutes.
The burden during the entire treatment course will be thus extra 30-40 minutes
scan time over a period of seven to eight weeks. Since MRI is not invasive with
no radiation burden, patients are not susceptible to radiation hazards.
However, being in a MRI for about an hour can be uncomfortable, therefore
patients are free to halt the procedure and withdraw from the motility MRI scan
at any time. Patients will not benefit from participation in this study.