Is it sensible to modulate ‘angular intensity’ in HDR brachytherapy for cervix cancer?

A new type of tandem applicator with a rotatable internal shielding structure was developed to enable direction-modulated brachytherapy (DMBT) in context of high-dose-rate treatment of cervical. The DMBT applicator was designed using a partially shielded rotatable tandem structure, which enables asymmetric dose ratio between open and shielded areas, thus more conformal dose distribution can be produced compared to a conventional tandem-and-ovoids (T&O) applicator. The dose-volume histogram for the clinical scenario with DMBT tandem showed potential advantages over the conventional method for improving target coverage while reducing dose to organs-at-risk such as rectum, sigmoid, bladder, and bowel. Its superior dose conformity to conventional T&O is obvious, hence this novel tool has a great potential for cervical cancer application while there are still more challenges which include inversed planning and optimised delivery, to address before its clinical implementation.

Adam Yeo

Peter MacCallum Cancer Centre
Senior Physicist