1 research outputs found
Supine MRI for regional breast radiotherapy: Imaging axillary lymph nodes before and after sentinel-node biopsy
Regional radiotherapy (RT) is increasingly used in breast cancer treatment.
Conventionally, computed tomography (CT) is performed for RT planning.
Lymph node (LN) target levels are delineated according to anatomical
boundaries. Magnetic resonance imaging (MRI) could enable individual LN
delineation. The purpose was to evaluate the applicability of MRI for LN
detection in supine treatment position, before and after sentinel-node biopsy
(SNB). Twenty-three female breast cancer patients (cTis-3N0M0) underwent
1.5 T MRI, before and after SNB, in addition to CT. Endurance for MRI was
monitored. Axillary levels were delineated. LNs were identified and delineated
on MRI from before and after SNB, and on CT, and compared by Wilcoxon
signed-rank tests. LN locations and LN-based volumes were related to axillary
delineations and associated volumes. Although postoperative effects were
visible, LN numbers on postoperative MRI (median 26 LNs) were highly
reproducible compared to preoperative MRI when adding excised sentinel
nodes, and higher than on CT (median 11, p < 0.001). LN-based volumes
were considerably smaller than respective axillary levels. Supine MRI of LNs
is feasible and reproducible before and after SNB. This may lead to more
accurate RT target definition compared to CT, with potentially lower toxicity.
With the MRI techniques described here, initiation of novel MRI-guided RT
strategies aiming at individual LNs could be possible