Explosive volcanism is a key contributor to climate variability on interannual to centennial timescales. Understanding the far-field societal impacts of eruption-forced climatic changes requires firm event chronologies and reliable estimates of both the burden and altitude (that is, tropospheric versus stratospheric) of volcanic sulfate aerosol. However, despite progress in ice-core dating, uncertainties remain in these key factors.
View Article and Find Full Text PDFAtlantic multidecadal variability is a coherent mode of natural climate variability occurring in the North Atlantic Ocean, with strong impacts on human societies and ecosystems worldwide. However, its periodicity and drivers are widely debated due to the short temporal extent of instrumental observations and competing effects of both internal and external climate factors acting on North Atlantic surface temperature variability. Here, we use a paleoclimate database and an advanced statistical framework to generate, evaluate, and compare 312 reconstructions of the Atlantic multidecadal variability over the past millennium, based on different indices and regression methods.
View Article and Find Full Text PDFBackground And Purpose: To investigate the reproducibility of deep-inspiration breath hold (DIBH) breast cancer treatments on Halcyon™ performed using the first clinical version of AlignRT InBore™ (Vision RT Ltd., London, UK), a Halcyon's SGRT dedicated solution.
Materials And Methods: The ease and feasibility of DIBH treatments was retrospectively investigated for the initial 22 left breast cancer patients treated on Halcyon™ using AlignRT InBore™.
Climate variability in the tropical Pacific affects global climate on a wide range of time scales. On interannual time scales, the tropical Pacific is home to the El Niño–Southern Oscillation (ENSO). Decadal variations and changes in the tropical Pacific, referred to here collectively as tropical Pacific decadal variability (TPDV), also profoundly affect the climate system.
View Article and Find Full Text PDFOvarian cancer is the fifth most common cancer in women in France with 4714 new cases in 2017. More than 70% of patients whose disease is initially locally advanced will present locoregional or distant recurrence. Therapeutic options in this situation are not consensual.
View Article and Find Full Text PDFPurpose: To evaluate the results of an adjuvant contact irradiation using 50kV photons after resection of conjunctival malignancies.
Materials And Method: From 2012 to 2014, 14 patients (male: nine; female: five) have been treated by contact irradiation after resection of a malignant tumor of the conjunctiva (melanoma: five patients; malignant fibrous histiocytoma: one patient; carcinoma: eight patients) The treatment was performed using the Papillon 50 machine (Ariane). Three to four sessions were delivered, each giving a dose of 10Gy.
The original version of this Article omitted a reference to previous work in 'Mann, M.E., Cane, M.
View Article and Find Full Text PDFA correction to this article has been published and is linked from the HTML version of this article.
View Article and Find Full Text PDFStratospheric aerosols from large tropical explosive volcanic eruptions backscatter shortwave radiation and reduce the global mean surface temperature. Observations suggest that they also favour an El Niño within 2 years following the eruption. Modelling studies have, however, so far reached no consensus on either the sign or physical mechanism of El Niño response to volcanism.
View Article and Find Full Text PDFPurpose: To verify the accuracy of volumetric arc therapy (VMAT) using the RapidArc™ device when switching patients from one single linear accelerator (linac) to a paired energy and mechanics "twin" linac without reoptimization of the original treatment plan.
Patients And Methods: Four centers using 8 linacs were involved in this study. Seventy-four patients previously treated with the 6MV photon RapidArc™ technique were selected for analysis, using 242 measurements.
For patients with cervical cancer, intensity-modulated radiation therapy (IMRT) improves target coverage and allows dose escalation while reducing the radiation dose to organs at risk (OARs). In this study, we compared dosimetric parameters among 3-dimensional conformal radiotherapy (3D-CRT), "step-and-shoot" IMRT, and volumetric intensity-modulated arc radiotherapy (VMAT) in a series of patients with cervical cancer receiving definitive radiotherapy. Computed tomography (CT) scans of 10 patients with histologically proven cervical cancer treated with definitive radiation therapy (RT) from December 2008 to March 2010 at our department were selected for this study.
View Article and Find Full Text PDFWhile bidecadal climate variability has been evidenced in several North Atlantic paleoclimate records, its drivers remain poorly understood. Here we show that the subset of CMIP5 historical climate simulations that produce such bidecadal variability exhibits a robust synchronization, with a maximum in Atlantic Meridional Overturning Circulation (AMOC) 15 years after the 1963 Agung eruption. The mechanisms at play involve salinity advection from the Arctic and explain the timing of Great Salinity Anomalies observed in the 1970s and the 1990s.
View Article and Find Full Text PDFThe Younger Dryas stadial, a cold event spanning 12,800 to 11,500 years ago, during the last deglaciation, is thought to coincide with the last major glacial re-advance in the tropical Andes. This interpretation relies mainly on cosmic-ray exposure dating of glacial deposits. Recent studies, however, have established new production rates for cosmogenic (10)Be and (3)He, which make it necessary to update all chronologies in this region and revise our understanding of cryospheric responses to climate variability.
View Article and Find Full Text PDFClimate indices based on sea surface temperature (SST) can synthesize information related to physical processes that describe change and variability in continental precipitation from floods to droughts. The South Atlantic Subtropical Dipole index (SASD) is based on the distribution of SST in the South Atlantic and fits these criteria. It represents the dominant mode of variability of SST in the South Atlantic, which is modulated by changes in the position and intensity of the South Atlantic Subtropical High.
View Article and Find Full Text PDFRadiotherapy for epithelioid hemangioendothelioma (EHE) using volumetric intensity-modulated arc radiotherapy (VMAT). A 48-year-old woman was referred for curative irradiation of a vertebral EHE after failure of surgery. A comparison between VMAT and conventional conformal tridimensional (3D) dosimetry was performed and potential advantage of VMAT for sparing critical organs from irradiation's side effects was discussed.
View Article and Find Full Text PDFThe purpose of this study was to analyze and revisit toxicity related to chest chemoradiotherapy and to correlate these side effects with dosimetric parameters obtained using analytical anisotropic algorithm (AAA) in locally unresectable advanced lung cancer. We retrospectively analyzed data from 47 lung cancer patients between 2005 and 2008. All received conformal 3D radiotherapy using high-energy linear accelerator plus concomitant chemotherapy.
View Article and Find Full Text PDFThe causes and timing of tropical glacier fluctuations during the Holocene epoch (10,000 years ago to present) are poorly understood. Yet constraining their sensitivity to changes in climate is important, as these glaciers are both sensitive indicators of climate change and serve as water reservoirs for highland regions. Studies have so far documented extra-tropical glacier fluctuations, but in the tropics, glacier-climate relationships are insufficiently understood.
View Article and Find Full Text PDFPurpose: Chemoradiotherapy is the standard treatment of inoperable and/or non-resectable IIIA/B non-small-cell lung cancer (NSCLC). Aware of the necessity to increase local control in locally advanced NSCLC, we analyzed the feasibility of high-dose three-dimensional conformal radiation therapy (3D-CRT) in the treatment of localised NSCLC.
Patients And Methods: We undertook a retrospective analysis of consecutive patients with non-resectable NSCLC treated with high-dose (74Gy) standard-fractionation 3D-CRT, with particular attention to the relationship between lung and heart radiation-induced toxicities.
Purpose: Hepatocellular carcinoma (HCC) is a poor prognosis tumor, and only 20% of patients will benefit from curative therapies (surgery, liver transplantation, percutaneous ablation). Although conventional radiotherapy has been traditionally regarded as inefficient and toxic for cirrhotic patients, three-dimensional conformal radiotherapy (3DCRT) has provided promising preliminary data for the treatment of HCC.
Methods And Materials: Prospective phase II trial including Child-Pugh A/B cirrhotic patients with small-size HCC (1 nodule < or =5 cm, or 2 nodules < or =3 cm) nonsuitable for curative treatments, to assess tolerance and efficacy of high-dose (66 Gy, 2 Gy/fraction) 3DCRT.
Purpose: Investigate whether the use of non coplanar fields and intensity modulated radiation therapy (IMRT) reduces the dose to the heart, in irradiation of middle and lower lung tumors.
Materials And Methods: Four plans are compared on 10 CT scans: (1) a reference plan, corresponding to coplanar plan of 3D conformal radiotherapy (3DCRT); (2) a 3DCRT(noncopl) plan, differing from reference plan by the change of one field in non coplanar fields; (3) an IMRT(copl) plan optimized on the same coplanar plan as reference plan; and (4) an IMRT(noncopl) plan optimized on the same non coplanar beams as 3DCRT(noncopl) plan. The equivalent uniform dose (EUD) for PTV was 74 Gy in 37 fractions.