Room: Exhibit Hall | Forum 4
Purpose: Describe a technique of intracavitary nasal high-dose rate (HDR) brachytherapy for treatment of a patient with recurrent Schneiderian carcinomatosis.
Methods: An endobronchial scope was used to visualize disease location and estimate distal and proximal extent from the nostril entrance. A pediatric nasogastric tube was inserted into each nostril first to aid in the placement of a 4mm inner diameter pediatric endotracheal (ET) tube. The ET tube was inserted to the pre-determined depth, with custom 3D printed stoppers that fit over each tube and rested against the nostrils to prevent the tubes from slipping deeper. Balloons on the ET tubes were inflated simultaneously with a mixture of saline and contrast to anchor and center the tubes in the sinonasal cavity, and their symmetric placement at the correct depth was verified on CT scout images. Custom 3D printed catheter guides fit into the end of each ET tube and held an HDR endobronchial catheter at the correct depth. A new CT scan was acquired daily, target and organ-at-risk contours rigidly transferred onto each new scan, and an HDR plan optimized for each dayâ€™s treatment.
Results: All fractions of HDR brachytherapy were delivered successfully with the described technique. Daily positioning of the ET tubes was not sufficiently reproducible to use the same HDR plan daily. However, the transfer of contours and simple applicator design, aided by 3D printed devices, allowed sufficiently rapid plan generation to complete daily treatment within 1-2 hours from the beginning of tube insertion.
Conclusion: Low dose-rate brachytherapy techniques were successfully adapted for HDR intranasal brachytherapy treatments. Two custom 3D printed devices were used to assist with the safety and reproducibility of nasal applicator insertion and treatment delivery. Daily CT scans were used for adaptive daily planning to optimize target coverage and organ-at-risk sparing.