RESUMEN
Background and purpose: Brachytherapy is treatment of choice for early stage nasal vestibule cancer. Over the years improvements were achieved by means of image guided target definition, interstitial implant techniques and also individual mold techniques. The aim of this study was to improve the technique of the implant so that the need for interstitial catheters can be limited by making use of patient individualized 3D-printed applicators. Materials and Methods: In 19 patients 3D-printed applicators were used to deliver pulse dose rate (PDR) brachytherapy. All patients underwent computed tomography (CT) and magnetic resonance imaging (MRI). A pre-plan with tumor delineation and manually optimized catheter positions to achieve tumor coverage was made. Based on the pre-plan a 3D-printed applicator was manufactured. Dose was evaluated by several indices: Conformity Index, Healthy Tissues Conformity Index, Dose Homogeneity Index, Dose non-uniformity ratio, Conformal index and high dose (HD) index. Results: A high target coverage was achieved, with a median V100%CTV of 99.1 % (range, 81.8-100 %) and median CI of 0.99 (range, 0.82-1.00), as well as a median V0.7GyGTV of 100 % (range, 93.0-100 %). The median HD was 0.39 (range, 0.20-0.83). Interstitial catheters were needed in 12 patients. None of the patients developed grade ≥ II toxicity within the median follow up of 18 months. Conclusions: This study shows that using 3D-printed applicators limits the need for interstitial catheters and also limits the high doses in normal tissue.
RESUMEN
Current online adaptive radiotherapy (oART) workflows require dedicated equipment. Our aim was to develop and implement an oART workflow for a C-arm linac which can be performed using standard clinically available tools. A workflow was successfully developed and implemented. Three patients receiving palliative radiotherapy for bladder cancer were treated, with 33 of 35 total fractions being delivered with the cone-beam computed tomography (CBCT)-guided oART workflow. Average oART fraction duration was 24 min from start of CBCT acquisition to end of beam on. This work shows how oART could be performed without dedicated equipment, broadening oART availability for application at existing treatment machines.