Margin Reduction Research Articles

A margin recipe for the management of intra-fraction target motion in radiotherapy.

Strategies to limit the impact of intra-fraction motion during treatment are common in radiotherapy. Margin recipes, however, are not designed to incorporate these strategies. This work aimed to provide a framework to determine how motion management strategies influence treatment margins. Two models of intra-fraction motion were considered. In model 1 motion was instantaneous, before treatment starts and in model 2 motion was a continuous drift during treatment. Motion management strategies were modelled by truncating the underlying error distribution at cσ, with σ the standard deviation of the distribution and c a free parameter. Using Monte Carlo simulations, we determined how motion management changed the required margin. The analysis was performed for different number of treatment fractions and different standard deviations of the underlying random and systematic errors. The required margin for a continuous drift was found to be well approximated by an average position of the target at ¾ of the drift. Introducing a truncation at cσ, the relative change in the margin was equal to 0.3c. This result held for both models, was independent of σ or the number of fractions and naturally generalizes to the situation with a residual (systematic) error. Treatment margins can be determined when motion management strategies are applied. Moreover, our analysis can be used to study the potential benefit of different motion management strategies. This allows to discuss and determine the most appropriate strategy for margin reduction.

Potential Benefit of Structural Health Monitoring System on Civil Jet Aircraft.

Structural health monitoring represents an interesting enabling technology towards increasing aviation safety and reducing operating costs by unlocking novel maintenance approaches and procedures. However, the benefits of such a technology are limited to maintenance costs reductions by cutting or even eliminating some maintenance scheduled checks. The key limitation to move a step further in exploiting structural health monitoring technology is represented by the regulation imposed in sizing aircraft composite structures. A safety margin of 2.0 is usually applied to estimate the ultimate loading that composite structures must withstand. This limitation is imposed since physical nondestructive inspection of composite structures is really challenging or even impossible in some cases. However, a structural health monitoring system represents a viable way for a real time check for the health status of a composite structure. Thus, the introduction of structural health monitoring should help into reducing the stringent safety margin imposed by aviation regulation for a safe design of composite structures. By assuming a safety margin reduction from 2.0 to 1.75 thanks to the installation of permanently attached sensors for structural health diagnostics, this paper assesses the potential fuel savings and direct operating costs through a multidisciplinary analysis on a A220-like aircraft. According to the foreseen level of technology, addressed through the number of sensors per square meter, a DOC saving from 2% up to 5% is achievable preserving, at the same time, all the key aircraft performance.

Impact of endorectal filling on interobserver variability of MRI based rectal primary tumor delineation

BackgroundOnline adaptive MR-guided radiotherapy allows for the reduction of safety margins in dose escalated treatment of rectal tumors. With the use of smaller margins, precise tumor delineation becomes more critical. In the present study we investigated the impact of rectal ultrasound gel filling on interobserver variability in delineation of primary rectal tumor volumes. MethodsSix patients with locally advanced rectal cancer were scanned on a 1.5 T MRI-Linac without (MRI_e) and with application of 100 cc of ultrasound gel transanally (MRI_f). Eight international radiation oncologists expert in the treatment of gastrointestinal cancers delineated the gross tumor volume (GTV) on both MRI scans. MRI_f scans were provided to the participating centers after MRI_e scans had been returned. Interobserver variability was analyzed by either comparing the observers’ delineations with a reference delineation (approach 1) and by building all possible pairs between observers (approach 2). Dice Similarity Index (DICE) and 95 % Hausdorff-Distance (95 %HD) were calculated. ResultsRectal ultrasound gel filling was well tolerated by all patients. Overall, interobserver agreement was superior in MRI_f scans based on median DICE (0.81 vs 0.74, p < 0.005 for approach 1 and 0.76 vs 0.64, p < 0.0001 for approach 2) and 95 %HD (6.9 mm vs 4.2 mm for approach 1, p = 0.04 and 8.9 mm vs 6.1 mm, p = 0.04 for approach 2). Delineated median tumor volumes and inter-quartile ranges were 26.99 cc [18.01–50.34 cc] in MRI_e and 44.20 [19.72–61.59 cc] in MRI_f scans respectively, p = 0.012. ConclusionsAlthough limited by the small number of patients, in this study the application of rectal ultrasound gel resulted in higher interobserver agreement in rectal GTV delineation. The endorectal gel filling might be a useful tool for future dose escalation strategies.

Clinical application of a sub-fractionation workflow for intrafraction re-planning during prostate radiotherapy treatment on a 1.5 Tesla MR-Linac: A practical method to mitigate intrafraction motion

BackgroundIntrafraction motion during radiotherapy limits margin reduction and dose escalation. Magnetic resonance (MR)-guided linear accelerators (MR-Linac) have emphasised this issue by enabling intrafraction imaging. We present and clinically apply a new workflow to counteract systematic intrafraction motion during MR-guided stereotactic body radiotherapy (SBRT). Materials and methodsWith the sub-fractionation workflow, the daily dose is delivered in multiple sequential parts (sub-fractions), each adapted to the latest anatomy. As each sub-fractionation treatment plan complies with the dose constraints, no online dose accumulation is required. Imaging and treatment planning are executed in parallel with dose delivery to minimise dead time, enabling an efficient workflow. The workflow was implemented on a 1.5 T MR-Linac and applied in 15 prostate cancer (PCa) patients treated with 5 × 7.25 Gy in two sub-fractions of 3.625 Gy (10 × 3.625 Gy in total). Intrafraction clinical target volume (CTV) motion was determined and compared to a workflow with single-plan delivery. Furthermore, required planning target volume (PTV) margins were determined. ResultsAverage on-table time was 42.7 min. Except for two fractions, all fractions were delivered within 60 min. Average intrafraction 3D CTV displacement (±standard deviation) was 1.1 mm (± 0.7) with the sub-fractionation workflow, whereas this was up to 3.5 mm (± 2.4) without sub-fractionation. Calculated PTV margins required with sub-fractionation were 1.0 mm (left–right), 2.4 mm (cranial-caudal), and 2.6 mm (anterior-posterior). ConclusionFeasibility of the sub-fractionation workflow was demonstrated in 15 PCa patients treated with two sub-fractions on a 1.5 T MR-Linac. The workflow allows for significant PTV margin reduction in these patients by reducing systematic intrafraction motion during SBRT.

A flexible tool for the assessment of the economic cost of pig disease in growers and finishers at farm level

Pigmeat is the most consumed red meat globally and consumption is expected to continue to increase. The sector is faced by the risk of epidemic and endemic disease impacts and other adverse influences. The aim of this study was to develop a dynamic simulation model of pig growing and finishing that can be used to model the financial and economic impacts of a variety of scenarios both related to disease effects and other influences on production. The model consists of a physical performance module and financial performance module. The core of the physical performance module comprises three stocks to model the flow of pigs from purchase to slaughter. Mortality rates, daily live weight gain and feed conversion ratios influence the dynamics of the physical performance. Since contracts between farmers and slaughterhouses often include large price penalties for over- and underweight pigs, carcase weight distribution is an important determinant of revenues. The physical performance module, therefore, simulates slaughter weight variations. The financial performance module calculates revenue, costs and gross margins. The revenue calculations take into account price penalties for over- and underweight pigs. To demonstrate the capabilities of the model, we apply the model to assess the economic consequences of production impacts associated with respiratory disease. We use estimated production impacts associated with respiratory disease from a study of all-in-all out growing and finishing systems based on pig production data and information from slaughterhouse monitoring in the UK. Our model suggests a reduction in the gross margin of nearly 40 % as a consequence of the estimated production impacts associated with a 10% increase in respiratory disease prevalence. Due to the lack of reliable information on slaughter weight variation, we also simulate the model using different assumptions about the slaughter weight distribution. An increase in the standard deviation of carcase weights from 8 kg to 12 kg, holding average weights constant, more than halves gross margins under our scenarios. We suggest that for all-in-all-out systems, carcase weight variation is likely to be a substantial factor in reducing income in the presence of respiratory disease and the economic impact of respiratory disease may be underestimated if the effects of disease on variation in carcase weights are not included in any analysis.

P02.11.B An hypothesis generating study of MRI-Derived Radiomics on tumor and microenvironment tissue heterogeneity to guide post-operative management of glioblastoma: toward personalized radiation treatment volume delineation

Abstract Background The glioblastoma’s bad prognosis is primarily due to intra-tumor heterogeneity, demonstrated from several studies that collected molecular biology, cytogenetic data and more recently radiomic features for a better prognostic stratification.The GLIFA project (GLIoblastoma Feature Analysis) is a multicentric project planned to investigated the role of radiomic analysis in GBM management, to verify if radiomic features in the tissue around the resection cavity which may guide the radiation target volume delineation. Material and Methods We retrospectively analyze from three centers radiomic features extracted from 90 patients with total or near total resection, who completed the standard adjuvant treatment and for whom we had post-operative images available for features extraction.The Manual segmentation was performed on post gadolinium T1w MRI sequence by 2 radiation oncologist reviewed by a neuroradiologist, both with at least 10 years of experience. The Region of interest (ROI) considered for the analysis were: the surgical cavity +/- post-surgical residual mass (CTV_cavity); the CTV a margin of 1.5 cm added to CTV_cavity and the volume resulting from subtracting the CTV_cavity from the CTV was defined as CTV_Ring. Radiomic analysis and modelling were conducted in RStudio. Z-score normalization was applied to each radiomic feature. A radiomic model was generated using the 226 features extracted from the Ring to perform a binary classification and predict the PFS at 6 months (statistical, morphological and textural features). A 3-fold cross-validation repeated five times was implemented for internal validation of the model. Results Two-hundred and seventy ROIs were contoured. The proposed radiomic model was given by the best fitting logistic regression model, and included the following 3 features: F_cm_merged.contrast, F_cm_merged.info.corr.2, F_rlm_merged.rlnu. A good agreement between model predicted probabilities and observed outcome probabilities was obtained (p-value of 0.49 by Hosmer and Lemeshow statistical test). The ROC curve of the model reported an AUC of 0.78 (95% CI: 0.68 - 0.88). Conclusion This is the first hypothesis-generating study who applies a radiomic analysis focusing on healthy tissue ring around the surgical cavity on post-operative MRI. This study provides a preliminary model for a decision support tool for a customization of the radiation target volume in GBM patients in order to achieve a margin reduction strategy.

Specifics of diagnostics and investigation of material properties in pipes with planar defects

The paper presents findings of a study on planar defects formed on the inner surface of gas pipeline metal in the operation process. The diagnostic indicators of a defective section were determined and analyzed using the intelligent pigging data. A broad range of research was carried out, including visual and measuring control of the object, step-by-step ultrasonic thickness measurement, chemical analysis, optical and electron microscopy, microhardness measurement of defective and defect-free areas, static tensile and impact bending tests. The structure and morphology of defective and defect-free areas were considered. It was determined that the cause of the defects is contamination of the source material with gas pores and fluorspar residues. The defects of planar nature are formed during rolling and can be characterized as metal delamination. The maximum detected thickness of the inclusions was 1.0 mm, however, the main part was rolled to 10.0 μm. The key feature of defects is their location on various levels throughout the wall cross-sections, ranging from one to four detected layers or groups of rolled discontinuities. It is shown that such defects lead to a change in the strength properties of defective area, uneven distribution of loads and reduction in safety margin of the object.

Radiopaque tissue transfer and X-ray system versus standard specimen radiography for intraoperative margin assessment in breast-conserving surgery: randomized clinical trial.

BackgroundReduction of positive margin rate (PMR) in breast-conserving surgery (BCS) of non-palpable breast cancer remains a challenge. The efficacy of intraoperative specimen radiography (SR) is unclear. This randomized trial evaluated whether the PMR was reduced by the use of devices that allow precise localization of the affected margins.MethodsPatients with microcalcification-associated breast cancer undergoing planned BCS were enrolled. Study participants were randomized to receive either SR with radiopaque tissue transfer and X-ray system (KliniTrayTM) or the institutional standard procedure (ISO). In all patients with a radiological margin less than 5 mm, an immediate re-excision was conducted. The primary outcome was the PMR. Risk factors for positive margins and the effect of immediate re-excision on final surgery were secondary analyses.ResultsAmong 122 randomized patients, 5 patients were excluded due to the extent of primary surgery and 117 were available for analysis. Final histopathology revealed a PMR of 31.7 per cent for the KliniTrayTM group and 26.3 per cent for the ISO group (P = 0.127). Independent factors for positive margins were histological tumour size more than 30 mm (adjusted OR (aOR) 10.73; 95 per cent c.i. 3.14 to 36.75; P < 0.001) and specimen size more than 50 mm (aOR 6.65; 95 per cent c.i. 2.00 to 22.08; P = 0.002). Immediate re-excision due to positive SR led to an absolute risk reduction in positive margins of 13.6 per cent (from 42.7 to 29.1 per cent).ConclusionSpecimen orientation with a radiopaque tissue transfer and X-ray system did not decrease the PMR in patients with microcalcification-associated breast cancer; however, SR and immediate re-excision proved to be helpful in the reduction of PMR.Registration numberDRKS00011527 (https://www.drks.de).

Effect of intrafraction adaptation on PTV margins for MRI guided online adaptive radiotherapy for rectal cancer

PurposeTo determine PTV margins for intrafraction motion in MRI-guided online adaptive radiotherapy for rectal cancer and the potential benefit of performing a 2nd adaptation prior to irradiation.MethodsThirty patients with rectal cancer received radiotherapy on a 1.5 T MR-Linac. On T2-weighted images for adaptation (MRIadapt), verification prior to (MRIver) and after irradiation (MRIpost) of 5 treatment fractions per patient, the primary tumor GTV (GTVprim) and mesorectum CTV (CTVmeso) were delineated. The structures on MRIadapt were expanded to corresponding PTVs. We determined the required expansion margins such that on average over 5 fractions, 98% of CTVmeso and 95% of GTVprim on MRIpost was covered in 90% of the patients. Furthermore, we studied the benefit of an additional adaptation, just prior to irradiation, by evaluating the coverage between the structures on MRIver and MRIpost. A threshold to assess the need for a secondary adaptation was determined by considering the overlap between MRIadapt and MRIver.ResultsPTV margins for intrafraction motion without 2nd adaptation were 6.4 mm in the anterior direction and 4.0 mm in all other directions for CTVmeso and 5.0 mm isotropically for GTVprim. A 2nd adaptation, applied for all fractions where the motion between MRIadapt and MRIver exceeded 1 mm (36% of the fractions) would result in a reduction of the PTVmeso margin to 3.2 mm/2.0 mm. For PTVprim a margin reduction to 3.5 mm is feasible when a 2nd adaptation is performed in fractions where the motion exceeded 4 mm (17% of the fractions).ConclusionWe studied the potential benefit of intrafraction motion monitoring and a 2nd adaptation to reduce PTV margins in online adaptive MRIgRT in rectal cancer. Performing 2nd adaptations immediately after online replanning when motion exceeded 1 mm and 4 mm for CTVmeso and GTVprim respectively, could result in a 30–50% margin reduction with limited reduction of dose to the bowel.

Correcting rotational error in rectal cancer radiation therapy: Can planning target volume margins be safely reduced?

The magnitude and impact of rotational error is unclear in rectal cancer radiation therapy. This study evaluates rotational errors in rectal cancer patients, and investigates the feasibility of planning target volume (PTV) margin reduction to decrease organs at risk (OAR) irradiation. In this study, 10 patients with rectal cancer were retrospectively selected. Rotational errors were assessed through image registration of daily cone beam computed tomography (CBCT) and planning CT scans. Two reference treatment plans (TPR ) with PTV margins of 5 mm and 10 mm were generated for each patient. Pre-determined rotational errors (±1°, ±3°, ±5°) were simulated to produce six manipulated treatment plans (TPM ) from each TPR . Differences in evaluated dose-volume metrics between TPR and TPM of each rotation were compared using Wilcoxon Signed-Rank Test. Clinical compliance was investigated for statistically significant dose-volume metrics. Mean rotational errors in pitch, roll and yaw were -0.72 ± 1.81°, -0.04 ± 1.36° and 0.38 ± 0.96° respectively. Pitch resulted in the largest potential circumferential displacement of clinical target volume (CTV) at 1.42 ± 1.06 mm. Pre-determined rotational errors resulted in statistically significant differences in CTV, small bowel, femoral heads and iliac crests (P < 0.05). Only small bowel and iliac crests failed clinical compliance, with majority in the PTV 10 mm margin group. Rotational errors affected clinical compliance for OAR dose but exerted minimal impact on CTV coverage even with reduced PTV margins. Both PTV margin reduction and rotational correction decreased irradiated volume of OAR. PTV margin reduction to 5 mm is feasible, and rotational corrections are recommended in rectal patients to further minimise OAR irradiation.

Mapping Local Failure Following Bladder Radiotherapy According to Dose

AimsTo determine the relationship between local relapse following radical radiotherapy for muscle-invasive bladder cancer (MIBC) and radiation dose. Materials and methodsPatients with T2-4N0-3M0 MIBC were recruited to a phase II study assessing the feasibility of intensity-modulated radiotherapy to the bladder and pelvic lymph nodes. Patients were planned to receive 64 Gy/32 fractions to the bladder tumour, 60 Gy/32 fractions to the involved pelvic nodes and 52 Gy/32 fractions to the uninvolved bladder and pelvic nodes. Pre-treatment set-up was informed by cone-beam CT. For patients who experienced local relapse, cystoscopy and imaging (CT/MRI) was used to reconstruct the relapse gross tumour volume (GTVrelapse) on the original planning CT . GTVrelapse D98% and D95% was determined by co-registering the relapse image to the planning CT utilising deformable image registration (DIR) and rigid image registration (RIR). Failure was classified into five types based on spatial and dosimetric criteria as follows: A (central high-dose failure), B (peripheral high-dose failure), C (central elective dose failure), D (peripheral elective dose failure) and E (extraneous dose failure). ResultsBetween June 2009 and November 2012, 38 patients were recruited. Following treatment, 18/38 (47%) patients experienced local relapse within the bladder. The median time to local relapse was 9.0 months (95% confidence interval 6.3–11.7). Seventeen of 18 patients were evaluable based on the availability of cross-sectional relapse imaging. A significant difference between DIR and RIR methods was seen. With the DIR approach, the median GTVrelapse D98% and D95% was 97% and 98% of prescribed dose, respectively. Eleven of 17 (65%) patients experienced type A failure and 6/17 (35%) patients type B failure. No patients had type C, D or E failure. MIBC failure occurred in 10/17 (59%) relapsed patients; of those, 7/11 (64%) had type A failure and 3/6 (50%) had type B failure. Non-MIBC failure occurred in 7/17 (41%) patients; 4/11 (36%) with type A failure and 3/6 (50%) with type B failure. ConclusionRelapse following radiotherapy occurred within close proximity to the original bladder tumour volume and within the planned high-dose region, suggesting possible biological causes for failure. We advise caution when considering margin reduction for future reduced high-dose radiation volume or partial bladder radiotherapy protocols.

Financing Restructuring During the Covid-19 Pandemic: The Tadhbiq Ahkam Paradigm

Purpose: The Paper is to study the Restukturization Of Financing During The Covid-19 Pandemic: Maqashid Paradigm As-Syar'iyahDesign/Method/Approach : This research uses qualitative methods with a library study approach. in analyzing the position of financing restucturization during the pandemic from the point of view of maqasid al-syar'iyahFindings: The discussion is considered important because by digging from the point of view of muamalah figh in terms of Magashid Syari’ah so that the discussion specifically becomes the first two discussions, from the restructuring process of financing during the pandemic, restructuring which was developed with the istimbat ahkam with the aim of magashid syari’ah as part of Hifdul Maal [Maintaining Property] which is motivated by the social condition of public health, namely during the pandemic period empirically with analysis and argumentation, the second is the harmonization of syari’ah policies with the situation. Research subject related to causes and reasons for implementing decisions on financing restricting with Magashid Syari’ah., a paradigm developed through financing risk mitigation and the Magashid As-Syari’ah paradigm in legal protection based on the existence of benefits that are dharuriyyat [primary needs]. Hajiyat [secondary needs], and Tahsinivat [tertiary needs], with regard to protection of proferty [hifdz a-Maal] and hifdz al –nafs [guarding the soul] with legal arguments built starting from the view that the return on financing is carried out from bank financial institutioins Sharia is an obligation that must be fulfilled, in the process of fulfilling the obligatons given by financial institutions based on general and special considerations, especialty for conditions beyons the will and ability of humans, the ability to return financing is hindered due the covid-19 pandemic, there is a restructuring formulation. A is, namely postponemet of loan principal, postponement of principal and margin, delay of remaining principal extension of repayment period, and reduction in margins on people’s business financing (PUR) Originality/Values: The main contribution of this research is a concern in filling the gap in how the concept of Islamic economics in the restucturization of financing to business actors

Assessment of planning target volume margins in 1.5 T magnetic resonance‐guided stereotactic body radiation therapy for localized prostate cancer

AbstractObjectiveWe aimed to determine the planning target volume margins applicable to magnetic resonance‐guided stereotactic body radiation therapy (MRgSBRT) of localized prostate cancer on a 1.5 T MR‐Linac.MethodsA total of 10 patients with low‐ to intermediate‐risk prostate cancer were retrospectively enrolled. All patients received five‐fraction MRgSBRT treatments, and underwent daily endorectal ballooning and bladder control. Five patients were implanted with the hydrogel rectal spacer. Three MR scans at each fraction were acquired to evaluate the intrafractional prostate motion. The required planning target volume margin was determined using the van Herk margin recipe based on direct MR‐MR prostate registration. The set‐up margin for localization using bony anatomy was also estimated.ResultsThe mean and standard deviation of translational displacement in left‐right (LR), superior‐inferior (SI), and anterior‐posterior (AP) directions were –0.3 ± 0.7, 2.0 ± 1.5, and 1.4 ± 1.1 mm, respectively. Planning target volume margins over the MRgSBRT fraction duration were 2.8 (LR), 5.3 (SI), and 3.9 mm (AP). Set‐up margins were estimated to 2.6 (LR), 3.3 (SI), and 3.3 mm (AP). Prostate motion increased considerably with treatment duration. Adapt‐to‐position had smaller intrafractional motions than adapt‐to‐shape. The rectal spacer insignificantly (p &gt; 0.1) reduced the prostate motion in SI and AP.ConclusionOnline workflow efficiency enhancement and intrafractional motion monitoring are vital for planning target volume margin reduction and precision enhancement in MRgSBRT.

The Use of Burnable Poisons in VVER-type Reactors to Reduce the Fraction of the Reactivity Margin Compensated by the Liquid System During Extended Runs

The paper presents the results of a computational and theoretical analysis of the use of various burnable poisons placed in a fuel rod for the maximum reduction in the reactivity margin compensated by a liquid system based on a boron absorber for VVER-type reactors operating in extended campaigns. Various layouts of fuel rods placement in fuel assemblies and with different concentrations of burnable poisons are considered, which are considered natural gadolinium and erbium. The analysis is carried out using simplified models of fuel burnup at partial refueling.

PO-1836 The Clinical Effectiveness of SGRT on Extremities Patients: Accuracy and Potential Margins Reduction

PO-1836 The Clinical Effectiveness of SGRT on Extremities Patients: Accuracy and Potential Margins Reduction

PO-1882 Impact of PTV margin reduction on organ at risk dose in short course radiotherapy of rectal cancer.

PO-1882 Impact of PTV margin reduction on organ at risk dose in short course radiotherapy of rectal cancer.

PO-1857 A feasibility study on RayPilot® real-time motion management for margin reduction in prostate SBRT.

PO-1857 A feasibility study on RayPilot® real-time motion management for margin reduction in prostate SBRT.

Early Withdrawal of Pandemic Unemployment Insurance: Effects on Employment and Earnings

We examine the effects of the sudden withdrawal of expanded pandemic unemployment benefits in June 2021 using anonymized bank transaction data for 16,253 individuals receiving unemployment insurance (UI) in April 2021. Comparing the difference-in-differences between states withdrawing and retaining expanded UI, we find that UI receipt falls 36.3 p.p., while employment rises by only 6.8 p.p. by early September. Average cumulative UI benefits fall by $2,529, while average cumulative earnings increase by only $292. Heterogeneity by unemployment duration implies that these effects are primarily driven by extensive margin expiration of benefits rather than by intensive margin reductions in the benefit level.

Learning quantile QoT models to address uncertainty over unseen lightpaths

Uncertainty in quality-of-transmission (QoT) estimation is traditionally addressed through empirical, myopic margins, ignoring the fact that each unseen lightpath is subject to different levels of uncertainty. To address this limitation, in this work, deep quantile regression is leveraged to finer capture QoT estimation uncertainty through the inference of margins that act discriminative over the unseen lightpaths. Specifically, deep-quantile regression is applied to approximate QoT models capable of inferring the QoT of unseen lightpaths, according to a predefined level of certainty. Quantile models automatically account for the uncertainty during inference, without the need to consider additional empirical margins for decision-making (i.e., the margins are learned and considered upon inference). It is shown that quantile QoT models lead to significant margin reduction when compared to baseline myopic margin schemes, resulting in more confident and network efficient allocation decisions.

Radiofrequency spectroscopy with intraoperative pathological assessment for breast carcinoma: synergistic or redundant?

ABSTRACT Background Published MarginProbe (Dune Medical Devices Ltd., Israel) data reports ≥50% reduction in positive lumpectomy margins. We sought to determine whether adjunctive use of MarginProbe would provide value over intraoperative pathologic assessment alone. Methods This is a retrospective chart review of 86 consecutive lumpectomies with MarginProbe from December 2018 to November 2019. Margins were considered positive using ‘no ink on tumor’ guideline for invasive cancer, and 2 mm or greater for ductal carcinoma in-situ. Significance was measured using Fisher’s exact test. Results Seventy-six patients yielded 86 lumpectomies for inclusion. Mean age was 69.8 and mean tumor size was 1.09 cm. Sixty-eight invasive cancers were assessed using adjunct MarginProbe and gross assessment, while 18 ductal carcinoma in-situ cases utilized MarginProbe only. Among all cases, gross assessment alone reduced positive margins(29.2% relative reduction, p = 0.28). Utilizing both modalities, positive margins decreased from 27.9% to 9.3% (66.7% relative reduction, p < 0.01) representing a 46.9% relative reduction versus gross assessment alone. After gross assessment and MarginProbe evaluation, additional excised volume averaged 2.9 cc. Conclusions Synergistic use of MarginProbe and gross assessment reduces positive margins during breast conserving surgery. Surgeons can weigh its cost against it benefit with the succinct analysis we provide.