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The impact of inlet boundary layer thickness on the unsteady aerodynamics of S-duct intakes

The need to reduce aero-engine emissions and direct operating costsis driving the civil aerospace sectortowards considering more integrated propulsion systems. Many of the proposed novel aircraft architectures employ convoluted intakes for either the aero-engine or propulsion system. These intakes are characterized by unsteady distortion that can hinder the performance and operability of the propulsion system. This work assessesthe impact of the inlet boundary layer on the unsteady aerodynamics of an S-duct intake using time-resolved particle image velocimetry at the aerodynamic interface plane.An increase in the boundary layer thickness at the intake inlet increasesthe flow unsteadiness on the swirl angle by up to 40% relativeto the baseline case. The azimuthal orientation of the inlet boundary layer modifies the intensity and topology of the most frequent swirl distortion pattern. For a relatively thick inlet boundary layer, the reduction of the dominant frequencies associated withthe unsteady swirl angle is postulated to be beneficial for the engine stability. Overall, this works gives guidelines for the integration between the intake and the engine across the range of potential inlet operating conditions

In vivo Raman spectroscopy for bladder cancer detection using a superficial Raman probe compared to a nonsuperficial Raman probe

Raman spectroscopy is promising as a noninvasive tool for cancer diagnosis. A superficial Raman probe might improve the classification of bladder cancer, because information is gained solely from the diseased tissue and irrelevant information from deeper layers is omitted. We compared Raman measurements of a superficial to a nonsuperficial probe, in bladder cancer diagnosis. Two-hundred sixteen Raman measurements and biopsies were taken in vivo from at least one suspicious and one unsuspicious bladder location in 104 patients. A Raman classification model was constructed based on histopathology, using a principal-component fed linear-discriminant-analysis and leave-one-person-out cross-validation. The diagnostic ability measured in area under the receiver operating characteristics curve was 0.95 and 0.80, the sensitivity was 90% and 85% and the specificity was 87% and 88% for the superficial and the nonsuperficial probe, respectively. We found inflammation to be a confounder and additionally we found a gradual transition from benign to low-grade to high-grade urothelial carcinoma. Raman spectroscopy provides additional information to histopathology and the diagnostic value using a superficial probe. </p

Patient preferences for treatment modalities for localised prostate cancer

OBJECTIVES: To assess the patient preferences and utility scores for the different conventional and innovative treatment modalities for localised prostate cancer (PCa). SUBJECTS AND METHODS: Patients treated for localised PCa and healthy volunteers were invited to fill out a treatment-outcome scenario questionnaire. Participants ranked six different treatments for localised PCa from most to least favourable, prior to information. In a next step, treatment procedures, toxicity, risk of biochemical recurrence and follow-up regimen were comprehensibly described for each of the six treatments (i.e. treatment-outcome scenarios), after which patients re-ranked the six treatments. Additionally, participants gave a visual analogue scale (VAS) and time trade-off (TTO) score for each scenario. Differences between utility scores were tested by Friedman tests with post hoc Wilcoxon signed-rank tests. RESULTS: Eighty patients and twenty-nine healthy volunteers were included in the study. Before receiving treatment-outcome scenario information, participants ranked magnetic resonance-guided adaptive radiotherapy most often as their first choice (35%). After treatment information was received, active surveillance was most often ranked as the first choice (41%). Utility scores were significantly different between the six treatment-outcome scenarios, and active surveillance, non- and minimal-invasive treatments received higher scores. CONCLUSIONS: Active surveillance and non-invasive treatment for localised PCa were the most preferred options by PCa patients and healthy volunteers and received among the highest utility scores. Treatment preferences change after treatment information is received

The first patient-reported outcomes from the Utrecht Prostate Cohort (UPC): the first platform facilitating 'trials within cohorts' (TwiCs) for the evaluation of interventions for prostate cancer

PURPOSE: To describe the development and first outcomes of the Utrecht Prostate Cohort (UPC): the first 'trials within cohorts' (TwiCs) platform for prostate cancer (PCa). METHODS: All non-metastasized, histologically proven PCa patients who are planned to receive standard of care are eligible for inclusion in UPC. Patients provide informed consent for the collection of clinical and technical patient data, physician-reported outcomes, and patient-reported outcomes (PROs) up to 10 years post-treatment. Additionally, patients may provide broad consent for future randomization for experimental-intervention trials (TwiCs). Changes in PROs (EPIC-26 questionnaire domains) of the participants who received standard of care were analyzed using Wilcoxon signed-rank tests. RESULTS: In two years, 626 patients were enrolled, 503 (80.4%) of whom provided broad consent for future randomization. Among these, 293 (46.8%) patients underwent magnetic resonance-guided adaptive radiotherapy (MRgRT), 116 (18.5%) CT-guided external beam radiation therapy (EBRT), 109 (17.4%) robot-assisted radical prostatectomy (RARP), and 65 (10.4%) patients opted for active surveillance. Patients treated with MRgRT and CT-guided EBRT showed a transient but significant decline in urinary irritative/obstructive and bowel domain scores at 1-month follow-up. RARP patients showed a significant deterioration of urinary incontinence domain scores between baseline and all follow-up moments and significant improvement of urinary irritative/obstructive domain scores between baseline and 9- and 12-month follow-up. All radical treatment groups showed a significant decline in sexual domain scores during follow-up. Active surveillance patients showed no significant deterioration over time in all domains. CONCLUSION: The first results from the UPC study show distinct differences in PROs between treatment options for PCa. REGISTRATION NO: NCT04228211

Interrater agreement of contouring of the neurovascular bundles and internal pudendal arteries in neurovascular-sparing magnetic resonance-guided radiotherapy for localized prostate cancer

Background and purpose: Radiation damage to neural and vascular tissue, such as the neurovascular bundles (NVBs) and internal pudendal arteries (IPAs), during radiotherapy for prostate cancer (PCa) may cause erectile dysfunction. Neurovascular-sparing magnetic resonance-guided adaptive radiotherapy (MRgRT) aims to preserve erectile function after treatment. However, the NVBs and IPAs are not routinely contoured in current radiotherapy practice. Before neurovascular-sparing MRgRT for PCa can be implemented, the interrater agreement of the contouring of the NVBs and IPAs on pre-treatment MRI needs to be assessed. Materials and methods: Four radiation oncologists independently contoured the prostate, NVB, and IPA in an unselected consecutive series of 15 PCa patients, on pre-treatment MRI. Dice similarity coefficients (DSCs) for pairwise interrater agreement of contours were calculated. Additionally, the DCS of a subset of the inferior half of the NVB contours (i.e. approximately prostate midgland to apex level) was calculated. Results: Median overall interrater DSC for the left and right NVB was 0.60 (IQR: 0.54 – 0.68) and 0.61 (IQR: 0.53 – 0.69) respectively and for the left and right IPA 0.59 (IQR: 0.53 – 0.64) and 0.59 (IQR: 0.52 – 0.64) respectively. Median overall interrater DSC for the inferior half of the left NVB was 0.67 (IQR: 0.58 – 0.74) and 0.67 (IQR: 0.61 – 0.71) for the right NVB. Conclusion: We found that the interrater agreement for the contouring of the NVB and IPA improved with enhancement of the MRI sequence as well as further training of the raters. The agreement was best in the subset of the inferior half of the NVB, where a good agreement is clinically most relevant for neurovascular-sparing MRgRT for PCa

Adaptive magnetic resonance-guided neurovascular-sparing radiotherapy for preservation of erectile function in prostate cancer patients

Background and purpose: Erectile dysfunction is a common adverse effect of external beam radiation therapy for localized prostate cancer (PCa), likely as a result of damage to neural and vascular tissue. Magnetic resonance-guided online adaptive radiotherapy (MRgRT) enables high-resolution MR imaging and paves the way for neurovascular-sparing approaches, potentially lowering erectile dysfunction after radiotherapy for PCa. The aim of this study was to assess the planning feasibility of neurovascular-sparing MRgRT for localized PCa. Materials and methods: Twenty consecutive localized PCa patients, treated with standard 5×7.25 Gy MRgRT, were included. For these patients, neurovascular-sparing 5×7.25 Gy MRgRT plans were generated. Dose constraints for the neurovascular bundle (NVB), the internal pudendal artery (IPA), the corpus cavernosum (CC), and the penile bulb (PB) were established. Doses to regions of interest were compared between the neurovascular-sparing plans and the standard clinical pre-treatment plans. Results: Neurovascular-sparing constraints for the CC, and PB were met in all 20 patients. For the IPA, constraints were met in 19 (95%) patients bilaterally and 1 (5%) patient unilaterally. Constraints for the NVB were met in 8 (40%) patients bilaterally, in 8 (40%) patients unilaterally, and were not met in 4 (20%) patients. NVB constraints were not met when gross tumor volume (GTV) was located dorsolaterally in the prostate. Dose to the NVB, IPA, and CC was significantly lower in the neurovascular-sparing plans. Conclusions: Neurovascular-sparing MRgRT for localized PCa is feasible in the planning setting. The extent of NVB sparing largely depends on the patient's GTV location in relation to the NVB