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Evapotranspiration (ET) plays a key role in hydrological impact studies and operational flood forecasting models as ET represents a loss of water from a catchment. Although ET is a major component of the catchment water balance, the evapotranspiration input for rainfall–runoff models is often simplified in contrast to the detailed estimates of catchment averaged precipitation. In this study, an existing conceptual rainfall–runoff model calibrated for and operational in the Bellebeek catchment in Belgium firstly has been validated and its sensitivity to different available potential ET input has been studied. It has been shown that when applying a calibrated rainfall–runoff model, the model input should be consistent with the input used for the calibration process, not only on the volume of ET, but also on the seasonal pattern. Secondly, estimates of the actual evapotranspiration based on measurements of a large aperture scintillometer (LAS) have been used as model forcing in the rainfall–runoff model. From this analysis, it has been shown that the actual evapotranspiration is a crucial factor in simulating the catchment water balance and the resulting stream flow. Regarding the actual evapotranspiration estimates from the LAS, it has been concluded that they can be considered realistic in summer months. In the months where stable conditions prevail (autumn, winter and (early) spring), an underestimation of the actual evapotranspiration is made, which has an important impact on the catchment's water balance.

The catchment averaged actual evapotranspiration rate is a hydrologic model variable that is difficult to quantify. Evapotranspiration rates – up till present – cannot be continuously observed at the catchment scale. The objective of this paper is to estimate the evapotranspiration rates (or its energy equivalent, the latent heat fluxes LE) for a heterogeneous catchment of 102.3 km2 in Belgium using three fundamentally different algorithms. One possible manner to observe this variable could be the continuous measurement of sensible heat fluxes (H) across large distances (in the order of kilometers) using a large aperture scintillometer (LAS), and converting these observations into evapotranspiration rates. Latent heat fluxes are obtained through the energy balance equation using a series of sensible heat fluxes measured with a LAS over a distance of 9.5 km in the catchment, and point measurements of net radiation (Rn) and ground heat flux (G) upscaled to catchment average through the use of TOPLATS, a physically based land surface model. The resulting LE-values are then compared to results from the remote sensing based surface energy balance algorithm ETLook and the land surface model. Firstly, the performance of ETLook for the energy balance terms has been assessed at the point scale and at the catchment scale. Secondly, consistency between daily evapotranspiration rates from ETLook, TOPLATS and LAS is shown.

Purpose: The aim of this study was to implement a clinically deliverable VMAT planning technique dedicated to advanced breast cancer, and to predict failed QA using a machine learning (ML) model to optimize the QA workload., Methods: For three planning methods (2A: 2-partial arc, 2AS: 2-partial arc with splitting, 4A: 4-partial arc), dosimetric results were compared with patient-specific QA performed with the electronic portal imaging device of the linac. A dataset was built with the pass/fail status of the plans and complexity metrics. It was divided into training and testing sets. An ML metamodel combining predictions from six base classifiers was trained on the training set to predict plans as 'pass' or 'fail'. The predictive performances were evaluated using the unseen data of the testing set., Results: The dosimetric comparison highlighted that 4A was the highest dosimetric performant method but also the poorest performant in the QA process. 2AS spared the best heart, but provided the highest dose to the contralateral breast and lowest node coverage. 2A provides a dosimetric compromise between organ at risk sparing and PTV coverage with satisfactory QA results. The metamodel had a median predictive sensitivity of 73% and a median specificity of 91%., Conclusions: The 2A method was selected to calculate clinically deliverable VMAT plans; however, the 2AS method was maintained when the heart was of particular importance and breath-hold techniques were not applicable. The metamodel provides promising predictive performance, and it is intended to be improved as a larger dataset becomes available., (Copyright © 2022 Associazione Italiana di Fisica Medica e Sanitaria. Published by Elsevier Ltd. All rights reserved.)

Prostate cancer (PCa) pelvic radiotherapy fields are defined by guidelines that do not consider individual variations in lymphatic drainage. We examined the feasibility of personalized sentinel lymph node (SLN)-based pelvic irradiation in PCa. Among a SLN study of 202 patients, we retrospectively selected 57 patients with a high risk of lymph node involvement. Each single SLN clinical target volume (CTV) was individually segmented and pelvic CTVs were contoured according to Radiation Therapy Oncology Group (RTOG) guidelines. We simulated a radiotherapy plan delivering 46 Gy and calculated the dose received by each SLN. Among a total of 332 abdominal SLNs, 305 pelvic SLNs (beyond the aortic bifurcation) were contoured (mean 5.4/patient). Based on standard guidelines, CTV missed 67 SLNs (22%), mostly at the common iliac level (40 SLNs). The mean distance between iliac vessels and the SLN was 11mm, and despite a 15mm margin around the iliac vessels, 9% of SLNs were not encompassed by the CTV. Moreover, 42 SLNs (63%) did not receive 95% of the prescribed dose. Despite a consensus on contouring guidelines, a significant proportion of SLNs were not included in the pelvic CTV and did not receive the prescribed dose. A tailored approach based on individual SLN detection would avoid underdosing pelvic lymph nodes that potentially contain tumor cells.

Pharyngo-oesophageal dyskinesias present a common symptomatology associated with those difficulties in swallowing for which the radio-manometric assessment is well known. Radiology, nevertheless, with an overall analysis of deglutition and its iatrogenic complications, as well as manometry of the superior oesophageal sphincter (OSS) with its diversity of results, according to the material, techniques, age, sex and stress involved, has convinced us of the necessity for a supplementary dynamic examination. Electromyography (EMG), simultaneously by the inferior constrictor (IC) and cricopharyngeal (CP) muscles, analyses with precision the electric activity of these two muscles, as well as the pharyngosphincteral synchronism. It is an easy examination, reproducible and without complications. In less than one year, nineteen patients suffering exclusively from a pharyngo-oesophageal dyskinesia benefited by this complete assessment. The secondary aetiologies are clearly predominant. Gastro-oesophageal reflux represents a quarter of those detected by an anamnesis alone. EMG detects 68% of functional anomaly of the OSS; manometry finds 47% and radiology 32%. Extramucosal myotomy of the OSS concerns incomplete or uncoordinated relaxation, preferentially by left cervical approach. The preliminary results, both clinical and manometric, are very satisfactory.

Dissolution of gallstones was observed 33 times in 22 patients. For 11 of them a recurrent lithiasis was dissolved by means of a second or third medical treatment. 21 patients have been followed for 3 to 6 years (median over 4 years). Without longstanding treatment the recurrence rate was 50 p. 100 in 3 years and 87.5 p. 100 in 6 years. Most of the patients should have relapsed in less than 9 years. Recurrences were always successfully treated with the same treatment but relapsed if the treatment was stopped (21 recurrences in 14 patients). A-1 month every 4 months-long standing treatment did not prevent recurrences in 8 patients whereas treatment every other month prevented recurrences in 5. It is therefore suggested to give long treatment after dissolution of gallstones to avoid recurrences. Its duration should be undefinite. Alternatives might include: 1) repeated dissolving treatments in case of recurrences, if relapses occur lately; 2) or longstanding treatment in case of early recurrences.

Among 54 patients with radiolucent asymptomatic gallstones treated by chenodeoxycholic acid (CDCA), 32 failures were observed. In 15 cases the size of gallstones did not change. In 11 cases the size of gallstones decreased but dissolution was not complete. In 6 cases the treatment had to be interrupted early because of the side-effects. In 10 patients (8.7 p. 100 of the treated patients) calcifications of gallstones occurred. In 9 patients (16.7 p. 100), a cholecystectomy had to be performed because of complications. The incidence of biliary complications necessitating cholecystectomy was significantly higher (p less than 0.001) in patients in whom CDCA failed to induce changes in gallstone size than in patients in whom CDCA was successful. Overall, a decrease of gallstones size was observed in 61 p. 100 of the 54 treated patients. However complete dissolution occurred in only two thirds of these patients. Patients in whom gallstone size decreased seldom presented with a biliary complication. Our data suggest that, when no obvious diminution of gallstones size is evident within six months of treatment, it is not advisable to continue the administration of CDCA. In case of failure, the responsibility of CDCA in the appearance of calcifications or even of complications necessitating cholecystectomy has to be discussed.