quantification of artifacts and image distortions in 1.5 tesla magnetic resonance images of a commercial multi-channel vaginal cylinder brachytherapy applicator set

Background: the bebig portio multi-channel applicator provides better target dose coverage and sparing organs-at-risk compared to a single-channel cylinder. however, artifacts and distortions of portio in magnetic resonance images (mri) have not yet been reported.objective: we aimed to quantify the artifacts and distortions in its 1.5-tesla mr images before clinical use.material and methods: in this experimental study, we employed a gelatin-filled phantom to conduct our measurements. t2-weighted (t2w) images were examined for artifacts and distortions. computed tomography (ct) images were used as a reference to assess image distortions. artifact severity was measured by recording the full-width-at-half-maximum (fwhm) image pixel values at various positions along the length of the applicator/channels. ct and mri-based applicator reconstruction accuracy were then compared, and signal-to-noise ratio (snr) and contrast were also determined for the applicator images.results: the applicator distortion level for the portio applicator was less than the image spatial resolution (0.5±0.5 pixels). the average fwhm for the tandem applicator images was 5.23±0.39 mm, while it was 3.21±0.37 mm for all channels (compared to their actual diameters of 5.0 mm and 3.0 mm, respectively). the average applicator reconstruction difference between ct and mr images was 0.75±0.30 mm overall source dwell positions. the image snr and contrast were both acceptable. conclusion: these findings indicate that the portio applicator has a satisfactory low level of artifacts and image distortions in 1.5-tesla, t2w images. it may, therefore, be a promising option for mri-guided multi-channel vaginal brachytherapy.