Development of a Brachytherapy Applicator with In-Vivo Dosimetry Using 3d Printing Technology for the Treatment of Gynaecological Cancers

Abstract

 Introduction: This study aimed to create a 3D-printed brachytherapy applicator with integrated in-vivo dosimetry and to find an optimal distance for the placement of peripheral catheters with a central tandem for treating gynaecological carcinoma.

Material and Methods: A 3D-printed applicator made of polylactic acid (PLA) with detachable components for in-vivo dosimetry was created and tested on a customized water phantom using TG-43 and model based algorithm. The developed sorbo applicator was used to build a strategy for analyzing Ir-192 brachytherapy source dose distribution using a virtual water phantom. Three sets of plans were investigated, one with a central source and the others with peripheral sources, utilizing needles and flexible catheters positioned at varied radial distances from the central source.

Results: The applicator was validated and found to have no significant changes in dosimetric and geometric features. The dose distribution with only the central source showed a rapid falloff near the source and a progressive falloff as distance increased. Peripheral sources loaded at the distance from 1.2 to 1.3 cm from the central source, resulted in improved dose asymmetry as well as reduced the dose to the organ at risk. Flexible catheters provide superior coverage. In-vivo dosimetry demonstrated optimized agreement with estimated dose.

Conclusion: The newly developed brachytherapy applicator, made with sophisticated 3D printing technology and incorporated in-vivo dosimetry, effectively optimizes dose distribution to both the vaginal walls and the vault apex. This novel design may be a dosage-guided therapy that improves dose delivery by changing the source position and dwell time.