Improved visualisation of cervix applicators for magnetic resonance-only-guided brachytherapy planning. Issue 2 (22nd January 2014)

• Record Type: Journal Article
• Authors: Liney, Gary P.; Marsden, Jenny E.; Horsfield, Carl J.; Murray, Tom; Manton, David J.; Beavis, Andrew W.
• Is Part Of: Journal of radiotherapy in practice. Volume 13:Issue 2(2013)
• Page Start: 159
• Page End: 165
• Publication Date: 2014-01-22
• Subjects: Radiotherapy -- Periodicals; 615.842005
• DOI: 10.1017/S1460396913000514
• Languages: English
• ISSNs: 1460-3969

Abstract

<abstract abstract-type="normal"> <title>Abstract</title> <sec id="abs1" sec-type="general"> <title>Objectives</title> <p>Current guidelines for image-guided cervical cancer brachytherapy planning recommend both computed tomography (CT) and magnetic resonance imaging (MRI) for adequate visualisation of the applicator and soft tissues, respectively. MRI-only planning would be ideal as it would save time within the patient pathway and avoid the concomitant CT exposures. However, applicator visualisation on MRI is usually achieved using fluid-filled fiducial marker tubes, which can be awkward to use and suffer from unwanted air bubble artefacts. Therefore, a new fiducial-free imaging technique was developed.</p> </sec> <sec id="abs2" sec-type="methods"> <title>Methods</title> <p>A dual echo time (TE) turbo spin echo sequence was used, at 1·5 T, to provide both T<sub>2</sub>-weighted images (100 ms TE) for tissue visualisation and strongly proton density-weighted images (17 ms TE) for improved applicator visualisation. In-house software was used to automatically segment the applicator in the short TE images (using Otsu's method) and transfer the information to the long TE images to provide a single fused dataset.</p> </sec> <sec id="abs3" sec-type="results"> <title>Results</title> <p>The method was evaluated successfully using titanium applicators in three patient cases and using a plastic applicator in a tissue-equivalent gel phantom.</p> </sec> <sec id="abs4" sec-type="conclusion"> <title>Conclusions</title> <p>The dual-echo technique provides a simple and efficient method for improving the visualisation of brachytherapy applicators in cervical cancer MRI images without the need for marker tubes.</p> </sec> </abstract>