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.

Background and purpose Clinical introduction of in-house developed medical devices in Europe requires conformity to the Medical Device Regulation (MDR) 2017/745 Article 5(5). Published experience on regulatory aspects of these devices is limited. This work describes our in-house development and verifications of the 3D printed patient-tailored ARCHITECT brachytherapy applicator and accompanying software, prepared to support clinical investigation and in-house use. Materials and methods Article 5(5) mandates an ‘appropriate’ quality management system (QMS) and exempts in-house medical devices from all MDR requirements except general safety and performance requirements (GSPRs). An institutional QMS was available, comprising documented procedures and fill-in templates for all project phases to compile technical documentation. In the first phase, the QMS requires a market analysis to justify the in-house exemption. In the design phase a prototype is developed, to be iteratively improved during manufacturing and verification phases, based on risk evaluations, verification tests, and processing constraints. Documentation is lastly compiled to support clinical investigations and routine use of the device. Results After confirming that no suitable marketed device was available, risk-based design and manufacturing approaches were used to safeguard in-house development. Verifications of material, manufacturing, mechanical safety, cleaning and sterilisation, use and workflow, and compatibility with procedures showed compliance with GSPRs. Simulated dosimetric benefits were observed compared to marketed devices. Conclusion The ARCHITECT applicator was developed in a systematic process, resulting in documented workflows and verification steps. Our approach provides a practical framework for MDR-compliant introduction of in-house equipment and can inform future best practice guidelines.

BACKGROUND AND PURPOSE: Although MRI-based image guided adaptive brachytherapy (IGABT) for locally advanced cervical cancer (LACC) has resulted in favorable outcomes, it can be logistically complex and time consuming compared to 2D image-based brachytherapy, and both physically and emotionally intensive for patients. This prospective study aims to perform time-action and patient experience analyses during IGABT to guide further improvements. MATERIALS AND METHODS: LACC patients treated with IGABT were included for the time-action (56 patients) and patient experience (29 patients) analyses. Times per treatment step were reported on a standardized form. For the patient experience analysis, a baseline health status was established with the EQ-5D-5L questionnaire and the perceived pain, anxiety and duration for each treatment step were assessed with the NRS-11. RESULTS: The median total procedure time from arrival until discharge was 530 (IQR: 480–565) minutes. Treatment planning (delineation, reconstruction, optimization) required the most time and took 175 (IQR: 145–195) minutes. Highest perceived pain was reported during applicator removal and treatment planning, anxiety during applicator removal, and duration during image acquisition and treatment planning. Perceived pain, anxiety and duration were correlated. Higher pre-treatment pain and anxiety scores were associated with higher perceived pain, anxiety and duration. CONCLUSION: This study highlights the complexity, duration and impact on patient experience of the current IGABT workflow. Patient reported pre-treatment pain and anxiety can help identify patients that may benefit from additional support. Research and implementation of measures aiming at shortening the overall procedure duration, which may include logistical, staffing and technological aspects, should be prioritized.

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 CTV_IR 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.

Background: The steep radiation dose gradients in cervical cancer brachytherapy (BT) necessitate a thorough understanding of the behavior of afterloader source cables or needles in the curved channels of (patient-tailored) applicators. Purpose: The purpose of this study is to develop and validate computer models to simulate: (1) BT source positions, and (2) insertion forces of needles in curved applicator channels. The methodology presented can be used to improve the knowledge of instrument behavior in current applicators and aid the development of novel (3D-printed) BT applicators. Methods: For the computer models, BT instruments were discretized in finite elements. Simulations were performed in SPACAR by formulating nodal contact force and motion input models and specifying the instruments’ kinematic and dynamic properties. To evaluate the source cable model, simulated source paths in ring applicators were compared with manufacturer-measured source paths. The impact of discrepancies on the dosimetry was estimated for standard plans. To validate needle models, simulated needle insertion forces in curved channels with varying curvature, torsion, and clearance, were compared with force measurements in dedicated 3D-printed templates. Results: Comparison of simulated with manufacturer-measured source positions showed 0.5–1.2 mm median and <2.0 mm maximum differences, in all but one applicator geometry. The resulting maximum relative dose differences at the lateral surface and at 5 mm depth were 5.5% and 4.7%, respectively. Simulated insertion forces for BT needles in curved channels accurately resembled the forces experimentally obtained by including experimental uncertainties in the simulation. Conclusion: The models developed can accurately predict source positions and insertion forces in BT applicators. Insights from these models can aid novel applicator design with improved motion and force transmission of BT instruments, and contribute to the estimation of overall treatment precision. The methodology presented can be extended to study other applicator geometries, flexible instruments, and afterloading systems.

Conformity of tumour volumes and dose plans in prostate brachytherapy (BT) can be constrained by unwanted needle deflections, needle access restrictions and visualisation limitations. This work validates the feasibility of teleoperated robotic control of an active steerable needle using magnetic resonance (MR) for guidance. With this system, perturbations can be counteracted and critical structures can be circumvented to access currently inaccessible areas. The system comprises of (1) a novel steerable needle, (2) the minimally invasive robotics in an MR environment (MIRIAM) system, and (3) the daVinci Research Kit (dVRK). MR scans provide visual feedback to the operator controlling the dVRK. Needle steering is performed along curved trajectories to avoid the urethra towards targets (representing tumour tissue) in a prostate phantom with a targeting error of 1.2 ± 1.0 mm. This work shows the potential clinical applicability of active needle steering for prostate BT with a teleoperated robotic system in an MR environment.

Figures 5 and 6 in this article intended to cite the following work: Boulnois, JL. Photophysical processes in recent medical laser developments: A review. Laser Med Sci 1, 47–66 (1986). https://doi.org/10.1007/BF02030737.

Background: The aim of surgery for advanced-stage ovarian cancer is a complete cytoreduction, because this is the most important independent prognostic factor for prolonged survival. Yet this can be difficult to achieve when there are micrometastases on the intestinal mesentery or intestines. The PlasmaJet device is an instrument to remove these micrometastases, but little is known about the depth of damage in human tissue compared to electrocoagulation devices. Methods: A prospective study was performed for the ex-vivo comparison of the histological depth of thermal damage of neutral argon plasma (PlasmaJet®) and electrocoagulation devices, in a series of 106 histological slides of 17 advanced-stage ovarian cancer patients. Depending on the tissue types resected during complete cytoreductive surgery, samples were collected from reproductive organs (uterus, ovaries), intestines (ileum, colon, rectum) and omentum, intestinal mesentery and peritoneum. Results: Average thermal damage depth was 0.15 mm (range 0.03–0.60 mm) after use of neutral argon plasma and 0.33 mm (range 0.08–1.80 mm) after use of electrocoagulation (p < 0.001). Greater disruption of the tissue surface was often observed after electrocoagulation. Conclusion: Our case series suggests that the use of neutral argon plasma during cytoreductive surgery produces significantly less thermal damage than electrocoagulation treatment. It is therefore considered a thermally safe alternative, aiding in the achievement of cytoreductive surgery.

Brachytherapy is a common treatment in cervical, uterine and vaginal cancer management. The technique is characterised by rapid developments in the fields of medical imaging, dosimetry planning and personalised medical device design. To reduce unnecessary burden on patients, assessments and training of these technologies should preferable be done using high-fidelity physical phantoms. In this study, anthropomorphic deformable phantoms of the vaginal wall and cavity were developed for image-guided adaptive brachytherapy, in which vaginal wall biomechanics were mimicked. Phantoms were produced from both silicone and polyvinyl alcohol materials. Material characterisations were performed with uniaxial tensile tests, via which Young’s moduli and toughness were quantified. In addition, the contrast between adjacent phantom layers was quantified in magnetic resonance images. The results showed that stress-strain curves of the silicone phantoms were within the range of those found in healthy human vaginal wall tissues. Sample preconditioning had a large effect on Young’s moduli, which ranged between 2.13 and 6.94 MPa in silicone. Toughness was a more robust and accurate metric for biomechanical matching, and ranged between 0.23 and 0.28 ·10⁶ J·m^-3 as a result of preconditioning. The polyvinyl alcohol phantoms were not stiff or tough enough, with a Young’s modulus of 0.16 MPa and toughness of 0.02 ·10⁶ J·m^-3. All materials used could be clearly delineated in magnetic resonance images, although the MRI sequence did affect layer contrast. In conclusion, we developed anthropomorphic deformable phantoms that mimic vaginal wall tissue and are well visible in magnetic resonance images. These phantoms will be used to evaluate the properties and to optimise the development and use of personalised brachytherapy applicators.

Purpose: To present a novel methodical approach to compare visibility of percutaneous needles in ultrasound images. Methods: A motor-driven rotation platform was used to gradually change the needle angle while capturing image data. Data analysis was automated using block-matching-based registration, with a tracking and refinement step. Every 25 frames, a Hough transform was used to improve needle alignments after large rotations. The method was demonstrated by comparing three commercial needles (14G radiofrequency ablation, RFA; 18G Trocar; 22G Chiba) and six prototype needles with different sizes, materials, and surface conditions (polished, sand-blasted, and kerfed), within polyvinyl alcohol phantom tissue and ex vivo bovine liver models. For each needle and angle, a contrast-to-noise ratio (CNR) was determined to quantify visibility. CNR values are presented as a function of needle type and insertion angle. In addition, the normalized area under the (CNR-angle) curve was used as a summary metric to compare needles. Results: In phantom tissue, the first kerfed needle design had the largest normalized area of visibility and the polished 1 mm diameter stainless steel needle the smallest (0.704 ± 0.199 vs. 0.154 ± 0.027, p < 0.01). In the ex vivo model, the second kerfed needle design had the largest normalized area of visibility, and the sand-blasted stainless steel needle the smallest (0.470 ± 0.190 vs. 0.127 ± 0.047, p < 0.001). As expected, the analysis showed needle visibility peaks at orthogonal insertion angles. For acute or obtuse angles, needle visibility was similar or reduced. Overall, the variability in needle visibility was considerably higher in livers. Conclusion: The best overall visibility was found with kerfed needles and the commercial RFA needle. The presented methodical approach to quantify ultrasound visibility allows comparisons of (echogenic) needles, as well as other technological innovations aiming to improve ultrasound visibility of percutaneous needles, such as coatings, material treatments, and beam steering approaches.