Nick J van de Berg

Automated planning of curved needle channels in 3D printed patient-tailored applicators for cervical cancer brachytherapy

Abstract Purpose. Patient-tailored intracavitary/interstitial (IC/IS) brachytherapy (BT) applicators may increase dose conformity in cervical cancer patients. Current configuration planning methods in these custom applicators rely on manual specification or a small set of (straight) needles. This work introduces and validates a two-stage approach for establishing channel configurations in the 3D printed patient-tailored ARCHITECT applicator. Methods. For each patient, the patient-tailored applicator shape was based on the first BT application with a commercial applicator and integrated connectors to a commercial (Geneva) intrauterine tube and two lunar ring channels. First, a large candidate set was generated of channels that steer the needle to desired poses in the target region and are contained in the applicator. The channels’ centrelines were represented by Bézier curves. Channels running between straight target segments and entry points were optimised and refined to ensure (dynamic) feasibility. Second, channel configurations were selected using geometric coverage optimisation. This workflow was applied to establish patient-tailored geometries for twenty-two patients previously treated using the Venezia applicator. Treatment plans were automatically generated using the in-house developed algorithm BiCycle. Plans for the clinically used configuration, T P clin , and patient-tailored configuration, T P arch , were compared. Results. Channel configurations could be generated in clinically feasible time (median: 2651 s, range 1826–3812 s). All T P arch and T P clin plans were acceptable, but planning aims were more frequently attained with patient-tailored configurations (115/132 versus 100/132 instances). Median CTVIR D 98 and bladder D 2 c m 3 doses significantly improved ( p < 0.001 and p < 0.01 respectively) in T P arch plans in comparison with T P clin plans, and in approximately half of the patients dosimetric indices improved. Conclusion. Automated patient-tailored BT channel configuration planning for 3D printed applicators is clinically feasible. A treatment planning study showed that all plans met planning limits for the patient-tailored configurations, and in selected cases improved the plan quality in comparison with commercial applicator configurations.

Personalised cutout saddle selection reduces perineal pain and improves cycling comfort in women with vulvar skin conditions

Perineal pain limits sitting and bicycling comfort in women with chronic vulvar conditions, reducing functional mobility and physical activity. This study evaluated personalised ergonomic saddle solutions to reduce perineal pain and restore cycling ability. Fifty women (age 57 ± 14 years) with lichen sclerosus, lichen planus, or vulvar cancer participated in a pre-post intervention study. In an outpatient living lab setting, participants evaluated four cutout saddle designs, received posture advice, selected a saddle, and tested it at home for 1-3 months. Outcomes included saddle pressure and centre-of-pressure metrics, trunk tilt, bicycling-related symptoms, quality of life, physical activity, user satisfaction, and personal goal achievement. A reference group of 50 healthy volunteers evaluated the saddles in the outpatient setting only. Pre-post cycling impediments (moderate or worse) decreased from 76.0% to 30.4% (p < 0.001), with marked reductions in perineal symptoms. Saddle design influenced centre-of-pressure location and variability, particularly in the anteroposterior direction. Seventy percent of participants achieved their personal bicycling goal. No changes were found in overall quality of life or physical activity. To conclude, personalised saddle selection reduces perineal pain and improves cycling ability in women with chronic vulvar conditions.

Clinical Feasibility of the ARCHITECT Applicator in Cervical Cancer Brachytherapy

This prospective, non-randomised, single centre, phase I trial assesses the clinical feasibility of the use of the patient-tailored ARCHITECT applicator in locally advanced cervical cancer brachytherapy.