11:30
Onco
Chair: Massimo Mischi
11:30
15 mins
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Proof-of-concept of a reusable metal heat and moisture exchanger
Maartje Leemans, Maarten van Alphen, Saar Muller, Boris van Putten, Bas Koper, Richard Dirven, Michiel van den Brekel
Abstract: Background: Optimal humidification by small passive Heat and Moisture Exchangers (HMEs) with low breathing resistance is crucial to diminish pulmonary complaints in patients with a tracheostomy or permanent tracheostoma after total laryngectomy. Current HMEs, consisting of a plastic cassette and foam core coated with hygroscopic salt, are marketed as disposables to ensure optimal functionality.1 However, the humidification performance of current disposable HMEs is not yet comparable to that of the normal upper respiratory tract, and full compliance has not been achieved in all patients.2,3 Therefore, pulmonary complaints remain prominent in this patient group, having a significant effect on their quality of life.4 Increasing the HME’s heat capacity is the most critical parameter to improve the HME’s performance.2 However, implementation within the current disposable HME design is not straightforward due to the trade-off between the HME’s performance, breathing resistance and dimensions, and consequently patient acceptance and compliance. We hypothesize that metal
3D printing can increase the heat capacity of the HME, thus improving the humidification performance and durability of HMEs while maintaining acceptable breathing resistance and size.
Methods: The humidification performance (water exchange) and breathing resistance of three stainless steel HME prototypes with different core designs and exterior dimensions comparable to available disposable HMEs were measured under standardized conditions.
Results: All HME prototypes are heavier but have a better humidification performance than the disposable HMEs under ambient conditions. The breathing resistance of the metal HME prototypes is in a similar range as the breathing resistance of the disposable HME.
Conclusions: A 3D-printed all-metal HME has the potential to provide a better-performing and durable alternative to disposable HMEs. Because the performance of the metal HME does not rely on a coating of hygroscopic salt, it is possible to clean and reuse the metal HME several times with a minimal loss of performance and functionality.
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11:45
15 mins
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Design and ex-vivo evaluation of a wasp-inspired needle for prostate cancer treatment
Jette Bloemberg, Fabian Trauzettel, Dimitra Dodou, Paul Breedveld
Abstract: Introduction: Prostate cancer treatments such as radical surgery and radiotherapy damage the cancer cells and the surrounding tissue, resulting in negative side effects. When prostate cancer is diagnosed at an early stage, local treatment via focal therapy is possible. Magnetic resonance imaging (MRI)-guided focal laser ablation to treat prostate cancer reduces side effects by preserving noncancerous tissue. Focal laser ablation requires a needle for positioning an optical fibre near the tumour. The insertion of a needle by pushing the needle into the tissue causes tissue motion, deformation, and damage. However, there may be an alternative; this study presents a wasp-inspired needle that can be inserted into prostate tissue with a zero external push force. The female parasitic wasp has a tube-like ovipositor that consists of parallel valves, which she slides back and forth to drill into wood with a zero external push force. Materials and methods: This study proposes an MRI-ready actuation system for an ovipositor-inspired needle that allows for insertion into tissue with zero external push force, without buckling and with the possibility of steering. The friction difference between the retracted and protruded parallel needle segments and the surrounding tissue initiates the needle’s self-propelling motion. We designed a manual actuator that drives six parallel needle segments that move independently in a reciprocating manner using a single input motion that is safe to use inside the MRI scanner. Our prototype of the manual actuator and the needle consists of 3D-printed parts and nitinol rods. We evaluated the needle performance in ex vivo human prostate tissue inside a preclinical MRI scanner. Results: The experimental evaluation of the prototype in ex vivo human prostate tissue showed that the needle tip was visible in MR images and that the needle could self-propel through prostate tissue. Discussion and conclusion: Our MRI-compatible design allows using a self-propelled steerable needle for minimally invasive MRI-guided procedures. The operator can track the needle on the MR image during the procedure, which allows for precise positioning. This study is a step towards developing a self-propelling needle for MRI-guided laser ablation to treat prostate cancer.
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12:00
15 mins
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Computer-aided decision support and 3D models in pancreatic cancer surgery
Diederik Rasenberg, Mark Ramaekers, Misha Luyer
Abstract: Background. Pancreatoduodenectomy is the cornerstone of surgical treatment for patients diagnosed with pancreatic head cancer. Preoperative planning is essential to assess vascular involvement of the tumor or aberrant arterial anatomy, however this requires specific expertise and can be challenging. Computer-aided detection (CAD) algorithms based on artificial intelligence techniques can provide pixel-level segmentations of the pancreatic tumor and may provide information on the resectability. This study assess the added value of three-dimensional (3D) patient models and computer-aided detection algorithms in determining resectability of pancreatic head tumors.
Methods. This study included 14 hepatopancreatobiliary experts (13 surgeons and 1 radiologist) from 8 different hospitals. Participants assessed pancreatic tumors in a simulated setting via a crossover design. Three radiologically resectable and three radiologically borderline resectable cases were included. Groups were divided in controls (using CT-scan), a 3D-group (using CT-scan and 3D models) and a CAD-group (using CT-scan, 3D and CAD). Perceived fulfilment of preoperative evaluation needs, the quality and confidence of clinical decision-making were evaluated between groups.
Results. A higher perceived ability to determine degrees and length of tumor-vessel contact was reported in the CAD-group compared to controls (P = 0.022 and P = 0.003, respectively). Lower degrees of tumor-vessel contact were predicted for radiologically borderline resectable tumors in the CAD-group compared to controls (P = 0.037). Higher confidence levels were observed in predicting the need for vascular resection in the 3D-group compared to the control group (P = 0.033) for all cases combined.
Conclusion. CAD (including 3D) improved the perceived ability for experts to accurately assess vessel involvement compared to conventional CT evaluation. CAD and 3D are evolving techniques that may result in better diagnosis and treatment of pancreatic cancer.
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12:15
15 mins
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Liquid biopsy-based decision support algorithms for diagnosis and subtyping of lung cancer
Esther Visser, Sylvia Genet, Remco de Kock, Ben van den Borne, Maggy Youssef-El Soud, Huub Belderbos, Gerben Stege, Marleen de Saegher, Susan van 't Westeinde, Luc Brunsveld, Maarten Broeren, Daan van de Kerkhof, Birgit Deiman, Federica Eduati, Volkher Scharnhorst
Abstract: Optimal treatment decisions of lung cancer (LC) patients are based on histological and/or molecular profiling of the tumor. Nowadays, this information is retrieved by pathologic subtyping of tissue biopsies. However, tissue biopsies could be inadequate for analysis or unavailable in e.g. fragile patients. Diagnosis could be supported by measurement of protein tumor markers (TMs) and circulating tumor DNA (ctDNA) in minimally invasively obtained liquid biopsies, i.e. a venous blood draw. In this multicenter prospective study, we evaluate the performance of liquid-biopsy based decision-support algorithms for diagnosis of LC and identification of the two main histological subtypes small and non-small-cell lung cancer (SCLC and NSCLC).
For 1096 patients with suspected LC, eight protein TMs (CA125, CA15.3, CEA, CYFRA 21-1, HE4, NSE, proGRP and SCCA) and ctDNA mutations in EGFR, KRAS and BRAF were analyzed in blood. Individual and combined TMs were used to train logistic regression models to identify LC, NSCLC or SCLC. To give better insight in the clinical applicability of the models, the performance of these models was evaluated at pre-specified positive predictive values (PPV) of ≥95% or ≥98%. For the combined TM models, only the most informative protein TMs selected by recursive feature elimination were included.
The best performing individual TMs allowed for identification of LC, NSCLC and SCLC patients with 46%, 25% and 40% sensitivity, respectively, at pre-specified PPVs. Combining multiple protein TMs and ctDNA resulted in significantly increased sensitivities of 65%, 67% and 50%, respectively. The LC model could identify a high fraction of stage IV LC patients (80%), but also allowed for identification of earlier stage patients (23% stage I and 44% stage II).
In conclusion, for a subset of patients suspected of LC, the diagnosis could be supported in a minimally invasive manner using liquid biopsy-based decision-support algorithms. In the future, these models may even help in the diagnosis of patients for whom pathologic subtyping is impossible or incomplete yet.
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12:30
15 mins
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Development of an in-vitro analysis tool to study the impact of the catheter tip location on particle distribution during radioembolization
Jan van der Hoek, Tess Snoeijink, Hadi Mirgolbabaee, Erik Groot Jebbink
Abstract: Introduction: Radioebolization is an established treatment method that is applied for non-resectable liver cancer. In this treatment method, radioactive particles are injected into one of the larger blood vessels by a microcatheter. The particles travel downstream towards the microvasculature, where they embolize and irradiate liver malignancies over time [1]. Unfortunately, many parameters can impact the clinical outcome of radioembolization that are not yet fully understood. Recently, Computational Fluid Mechanics (CFD) studies have shown that the catheter tip location within the arterial cross-section has a major impact on the downstream microparticle distribution [2-4]. While the results offer much insight, validation is still required. This work presents an overview of a developed in-vitro setup that allows for a highly accurate placement and mapping of a microcatheter to enable replication of the CFD studies.
Method: An in-vitro setup was built around a symmetrical, 2D hepatic artery phantom, that bifurcates three times into a total of eight outlets. A controlled injection at a specific radial location is realized by using a rigid capillary pipe mounted in an injection device. The catheter tip location is placed accurately using two cameras for the top and side view (Logitech BRIO, Lausanne, Switzerland). By using a colour threshold segmentation algorithm on the video footage of the experiments, detailed information about the catheter tip location and movement is obtained and presented in catheter tip heat maps.
Results: Comparison of the heat maps show a catheter cross-sectional placement within 0.1mm of the desired location for all experiments. Moreover, the heat maps quantify the movement of the catheter tip during a cardiac cycle, visible by a slight deviation of the location during the systolic phase.
Conclusion: The accurate placement of the catheter allows for a controlled in-vitro test environment to test catheter injection parameters. Together with a quantification of the catheter movement, comparison with numerical results becomes more straightforward.
References:
[1] Salem R. et al., Clinical Gastroenterology and Hepatology, 2013
[2] Basciano et al., Annals of Biomedical Engineering, 2010
[3] Kleinstreuer et al., World Journal of Clinical Cases, 2014
[4] Bomberna et al., Expert Opinion on Drug Delivery, 2020
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12:45
15 mins
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Steerable needles enable high-dose-rate prostate brachytherapy for patients with pubic arch interference
Martijn de Vries, Miranda Christianen, Lorne Luthart, Kim de Vries, Inger-Karine Kolkman-Deurloo, John van den Dobbelsteen
Abstract: Prostate cancer patients with an enlarged prostate and/or excessive pubic arch interference (PAI) are generally considered non-eligible for treatment with high-dose-rate brachytherapy (HDR BT). Recently, steerable needles have been developed that allow for high targeting accuracy and curved needle trajectories (de Vries et al. PLOS One, 2021). This study validates 1) the ability of these steerable needles to avoid PAI and 2) the feasibility of implanting the steerable needles according to the pre-treatment plan in the clinical setting.
HDR BT treatment planning and implantation studies were performed with steerable needles and a prostate phantom with an enlarged prostate (> 55 cm3) and excessive PAI (10 mm). Four pre-treatment plans were generated in the Oncentra® Prostate (OCP) treatment planning system (TPS) (Elekta Instrument AB, Sweden) considering the dosimetric constraints: prostate V100 > 95%, urethra D0.1cm3 < 115% and rectum D1cm3 < 75%. Plan A did not consider PAI functioning as the baseline plan. The other pre-treatment plans considered PAI of which plans B and C only used rigid needles and plan D incorporated rigid and steerable needles to overcome PAI. Dose-volume histogram (DVH) outcomes evaluated the quality of the pre-treatment plans and conformance to these plans after implantation.
The DVH values of the steerable needle plan approached upon the outcomes for the baseline plan and increased prostate V100 up to 17.1% compared to the rigid needle plans. The dose to the urethra remained below the dose criteria of 115%. The physician was able to implant the steerable needle plan with the highest conformance to the pre-treatment plan, no major changes in the clinical workflow, and no changes in the clinical set-up.
The steerable needle approach allows for more flexibility in needle placement, mitigation of deflections and the avoidance of PAI. The curved trajectories can be easily planned in the OCP TPS and implantation can be performed with excellent agreement between pre-treatment and postimplant plan. An adequate dose distribution can be achieved, and hence, men with enlarged and/or excessive PAI can be considered to be treated with HDR BT.
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