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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 V0.7Gy GTV 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., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier B.V. on behalf of European Society of Radiotherapy & Oncology.)

Background and Purpose: Applying needles in the first brachytherapy (BT) fraction for patients with locally advanced cervical cancer allows for more dose conformality and OAR sparing, but is more challenging than in subsequent fractions, as pre-implant imaging with applicator in situ is lacking. We investigate whether a needle simulation, a fixed needle configuration or a multidisciplinary discussion-based configuration can predict more accurately which applicator needle positions are best suited for use in the first BT fraction., Materials and Methods: For 20 patients we retrospectively determined the "reference" needle configuration (RC) for the first BT fraction using magnetic resonance imaging (MRI) scans with applicator in situ . We simulated a pre-MRI needle configuration (PC) using the MRI made in the fourth week of external beam radiotherapy (EBRT) without applicator in situ . We generated a fixed needle configuration (FC) from the most common RC needles. Using Dice's similarity coefficient (DSC) we compared each of these needle configurations, including the clinically applied "multidisciplinary consensus" needle configuration (MC), with RC. We considered two scenarios: allowing up to ten needles (scenario 1), and limiting the needle number (scenario 2). The analysis was repeated omitting two mid-ventral needles previously determined as non-essential to treatment planning., Results: For both scenarios, the median DSC for PC and FC was higher than for MC (scenario1:DSC PC  = 0,78; DSC FC  = 0,75; DSC MC  = 0,57; scenario 2:DSC PC  = 0,74; DSC FC  = 0,73; DSC MC  = 0,59), while omitting mid-ventral needles resulted in no statistically significant differences in DSC., Conclusions: The PC or FC method are at least as accurate as the MC, with the FC preferred for efficiency., (© 2019 The Authors.)

Background and Purpose: High-risk prostate cancer patients are frequently treated with external-beam radiotherapy (EBRT). Of all patients receiving EBRT, 15-35% will experience biochemical recurrence (BCR) within five years. Magnetic resonance imaging (MRI) is commonly acquired as part of the diagnostic procedure and imaging-derived features have shown promise in tumour characterisation and biochemical recurrence prediction. We investigated the value of imaging features extracted from pre-treatment T2w anatomical MRI to predict five year biochemical recurrence in high-risk patients treated with EBRT., Materials and Methods: In a cohort of 120 high-risk patients, imaging features were extracted from the whole-prostate and a margin surrounding it. Intensity, shape and textural features were extracted from the original and filtered T2w-MRI scans. The minimum-redundancy maximum-relevance algorithm was used for feature selection. Random forest and logistic regression classifiers were used in our experiments. The performance of a logistic regression model using the patient's clinical features was also investigated. To assess the prediction accuracy we used stratified 10-fold cross validation and receiver operating characteristic analysis, quantified by the area under the curve (AUC)., Results: A logistic regression model built using whole-prostate imaging features obtained an AUC of 0.63 in the prediction of BCR, outperforming a model solely based on clinical variables (AUC = 0.51). Combining imaging and clinical features did not outperform the accuracy of imaging alone., Conclusions: These results illustrate the potential of imaging features alone to distinguish patients with an increased risk of recurrence, even in a clinically homogeneous cohort., (© 2018 The Authors.)