On EM Reconstruction of a Multi Channel Shielded Applicator for Cervical Cancer Brachytherapy: A Feasibility Study

TL;DR

This study demonstrates the feasibility of electromagnetic tracking for reconstructing individual channels of a shielded applicator in cervical cancer brachytherapy, showing accuracy within 2 mm and no significant influence of shielding on data quality.

Contribution

It presents a proof-of-concept for EMT-based reconstruction of shielded applicator channels, including analysis of shield effects and measurement accuracy.

Findings

Reconstruction accuracy within 2 mm of CAD dimensions.

Shielding does not significantly affect EMT data.

All reconstructed channels are within geometrical tolerances.

Abstract

Electromagnetic tracking (EMT) is a promising technology for automated catheter and applicator reconstruc- 10 tions in brachytherapy. In this work, a proof-of-concept is presented for reconstruction of the individual channels of a shielded tandem applicator dedicated to intensity modulated brachytherapy. All six channels of a straight prototype was reconstructed and the distance between two opposite channels was measured. A study was also conducted on the influence of the shield on the data fluctuation of the EMT system. The differences with the CAD specified dimensions are under 2 mm. The pair of channels which has one of it more distant from the generator have 15 higher inter-channel distance with higher variability. In the first 110 cm reconstruction, all inter-channel distances are within the geometrical tolerances. According to a paired Student t-test, the data given by the EM system with and without the shield applicator tip are not significantly different. This study shows that the reconstruction of channel path within the mechanical accuracy of the applicator is possible.