Abstract

Objective: The HDR brachytherapy obtained by 3D planning meets with considerable risk by many specialists. However, the advantages of this therapy may outweigh the disadvantages. The aim of the work is to compare 3D planning with standard 2D planning for palliative treatment of oesophageal cancer and intended for HDR brachytherapy. Methods: We used radioactive Ir-192 source, HDR device, CT scanner. The plans were prepared using Oncentra Brachyplan with 3D and 2D reconstruction module. In both methods, source dwell positions every 0.5 cm were considered. To compare both methods, doses per each organ in a volume of 0.01 ccm, 2 ccm and 5 ccm were calculated. Also V100, V120, V90, V150 and V200 in PTV was estimated. For consistency of the results, a therapeutic dose of 100 cGy was used. Results: For the 3D method, the reference dose covers PTV in 72.56% of the total area volume, whereas for 2D, this is only 55.98%. Results for the other equivalents of reference dose are similar. Significantly lower values were obtained for dose equal to 200% of the reference dose, as compared to other doses. For the 3D method, 25.12% covering of PTV was obtained, while it was only 19.73% for the 2D method. Conclusion: As compared to 2D method, the 3D method is more accurate and provides better dose covering of PTV. It allows constant monitoring of doses delivered to organs at risk. This research prove that 3D planning makes HDR brachytherapy in palliative treatment of oesophageal cancer more effective.