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Improved visualisation of cervix applicators for magnetic resonance-only-guided brachytherapy planning

  • Gary P. Liney (a1), Jenny E. Marsden (a1), Carl J. Horsfield (a1), Tom Murray (a1), David J. Manton (a1) and Andrew W. Beavis (a1)...

Abstract

Objectives

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.

Methods

A dual echo time (TE) turbo spin echo sequence was used, at 1·5 T, to provide both T2-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.

Results

The method was evaluated successfully using titanium applicators in three patient cases and using a plastic applicator in a tissue-equivalent gel phantom.

Conclusions

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.

Copyright

Corresponding author

Correspondence to: Andrew W. Beavis, Radiation Physics Department, Queen's Centre for Oncology and Haematology, Castle Hill Hospital, Cottingham, East Yorkshire, HU16 5JQ, UK. Tel. 01482 461384. E-mail: andy.beavis@hey.nhs.uk.

References

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Keywords

Improved visualisation of cervix applicators for magnetic resonance-only-guided brachytherapy planning

  • Gary P. Liney (a1), Jenny E. Marsden (a1), Carl J. Horsfield (a1), Tom Murray (a1), David J. Manton (a1) and Andrew W. Beavis (a1)...

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