Related Experiment Video
Updated: Feb 18, 2026
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
Quantitative CT assessment of a novel direction-modulated brachytherapy tandem applicator
Alyaa H Elzibak1, Petronella M Kager2, Abraam Soliman3
1Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada.
Purpose:
The purpose of this study was to quantitatively assess the CT metal-induced artifacts from a novel direction-modulated brachytherapy (DMBT) tandem applicator prototype, recently designed for cervical cancer treatments.
Methods And Materials:
A water-based pelvic phantom was constructed for CT scanning. The DMBT applicator was imaged using our institutional protocol, one with higher kVp and mAs settings, and repetition of these protocols using 3-mm slices. A conventional stainless steel applicator was also scanned. In addition to the standard reconstructed images, applicator images were reconstructed using a commercial metal artifact-reduction (MAR) algorithm and an in-house-developed research algorithm. Subsequently, image quality and artifact severity were evaluated.
Results:
Artifact severity, measured in terms of SDs in CT numbers, decreased asymptotically to background water levels with the distance away from the applicator. Artifact-reduction algorithms lead to significant and visible improvements in image quality, with >50% and >20% decrease in artifact severity achieved at a 10-mm distance for the DMBT and stainless steel applicators, respectively. Differences in artifact severity were minimal between the four imaging protocols. DMBT dimensions were the same on images with and without the commercial MAR algorithm, within <1 mm of the theoretical value. Both the commercial and in-house algorithms restored the CT numbers outside the applicator, albeit a better performance was achieved by the in-house algorithm.
Conclusions:
The artifacts produced by both applicators were minimized with the use of MAR algorithms. Adoption of the DMBT and stainless steel applicators for CT-guided brachytherapy is anticipated as MAR algorithms are widely available on CT scanners.
