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.
Peter MacCallum Cancer Centre