RESUMEN
Potassium-40 is a widespread, naturally occurring isotope whose radioactivity impacts subatomic rare-event searches, nuclear structure theory, and estimated geological ages. A predicted electron-capture decay directly to the ground state of argon-40 has never been observed. The KDK (potassium decay) collaboration reports strong evidence of this rare decay mode. A blinded analysis reveals a nonzero ratio of intensities of ground-state electron-captures (I_{EC^{0}}) over excited-state ones (I_{EC^{*}}) of I_{EC^{0}}/I_{EC^{*}}=0.0095±[over stat]0.0022±[over sys]0.0010 (68% C.L.), with the null hypothesis rejected at 4σ. In terms of branching ratio, this signal yields I_{EC^{0}}=0.098%±[over stat]0.023%±[over sys]0.010%, roughly half of the commonly used prediction, with consequences for various fields [27L. Hariasz et al., companion paper, Phys. Rev. C 108, 014327 (2023)PRVCAN2469-998510.1103/PhysRevC.108.014327].
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BACKGROUND & AIMS: Weight loss and malnutrition are frequent problems in oncology patients. The aim of this study was to get a perspective of the current practice of parenteral nutrition (PN) care in an outpatient setting and to improve patient-centered nutritional care. METHODS: Fifty-three outpatient oncology centers participated in this observational study performed between July 2010 and March 2011. All participating centers entered data online into a web-based documentation form, containing a number of oncology patients, diagnoses, and detailed data about oncology patients receiving PN. RESULTS: Two cohorts were analyzed. First cohort consisted of all oncology patients in quarter 04/2010. Second cohort consisted of patients with PN during the whole studying period. In the first cohort 2.46% (n = 626) of 25,424 oncology patients received PN. Most frequent diagnoses of patients receiving PN were gastric cancer (n = 119) and colorectal cancer (n = 104), however most stated diagnosis was "other" (n = 163). In the second cohort (n = 1137), a common indication for PN was impaired gastrointestinal passage (n = 177), although here again most stated reason was "other" (n = 924). In the course of the PN treatment, patients (n = 1137) showed a stable or slowly increasing body mass index (from 21.6 ± 3.8 kg/m(2) to 21.8 ± 3.5 kg/m(2)). CONCLUSION: This is the largest study outlining the characteristics of oncology patients in the context of PN in German ambulatory centers. They confirm the important role of PN in the care of gastrointestinal cancer. Further studies have to be performed to identify if other indications than those mentioned in relevant guidelines can trigger initiation of PN.
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Neoplasias Gastrointestinales/dietoterapia , Oncología Médica/métodos , Terapia Nutricional/métodos , Nutrición Parenteral/métodos , Atención al Paciente/métodos , Anciano , Índice de Masa Corporal , Femenino , Neoplasias Gastrointestinales/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Terapia Nutricional/normas , Terapia Nutricional/tendencias , Observación , Nutrición Parenteral/efectos adversos , Guías de Práctica Clínica como Asunto , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
In this work, we present the results of the experimental characterization of the DRAGO (DRift detector Array-based Gamma camera for Oncology), a detection system developed for high-spatial resolution gamma-ray imaging. This camera is based on a monolithic array of 77 silicon drift detectors (SDDs), with a total active area of 6.7 cm(2), coupled to a single 5-mm-thick CsI(Tl) scintillator crystal. The use of an array of SDDs provides a high quantum efficiency for the detection of the scintillation light together with a very low electronics noise. A very compact detection module based on the use of integrated readout circuits was developed. The performances achieved in gamma-ray imaging using this camera are reported here. When imaging a 0.2 mm collimated (57)Co source (122 keV) over different points of the active area, a spatial resolution ranging from 0.25 to 0.5 mm was measured. The depth-of-interaction capability of the detector, thanks to the use of a Maximum Likelihood reconstruction algorithm, was also investigated by imaging a collimated beam tilted to an angle of 45 degrees with respect to the scintillator surface. Finally, the imager was characterized with in vivo measurements on mice, in a real preclinical environment.
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Cámaras gamma , Algoritmos , Animales , Huesos/diagnóstico por imagen , Diseño de Equipo , Miembro Anterior/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Funciones de Verosimilitud , Pulmón/diagnóstico por imagen , Oncología Médica/instrumentación , Ratones , Cintigrafía/instrumentación , Cintigrafía/métodosRESUMEN
The Austrian Landfill Ordinance provides limit values regarding the reactivity for the disposal of mechanically biologically treated (MBT) waste before landfilling. The potential reactivity determined by biological tests according to the Austrian Standards (OENORM S 2027 1-2) can be underestimated if the microbial community is affected by environmental conditions. New analytical tools have been developed as an alternative to error-prone and time-consuming biological tests. Fourier Transform Infrared (FT-IR) spectroscopy in association with Partial Least Squares Regression (PLS-R) was used to predict the reactivity parameters respiration activity (RA(4)) and gas generation sum (GS(21)) as well as to detect errors resulting from inhibiting effects on biological tests. For this purpose 250 MBT-waste samples from different Austrian MBT-plants were investigated using FT-IR spectroscopy in the mid (MIR) and near infrared (NIR) area and biological tests. Spectroscopic results were compared with those from biological tests. Arising problems caused by interferences of RA(4) and GS(21) are discussed. It is shown that FT-IR spectroscopy predicts RA(4) and GS(21) reliably to assess stability of MBT-waste materials and to detect errors.
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Monitoreo del Ambiente/métodos , Análisis Multivariante , Eliminación de Residuos , Residuos/análisis , Austria , Biodegradación Ambiental , Ciudades , Monitoreo del Ambiente/normas , Análisis de los Mínimos Cuadrados , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Methane emissions from active or closed landfills can be reduced by means of methane oxidation enhanced in properly designed landfill covers, known as "biocovers". Biocovers usually consist of a coarse gas distribution layer to balance gas fluxes placed beneath an appropriate substrate layer. The application of such covers implies use of measurement methods and evaluation approaches, both during the planning stage and throughout the operation of biocovers in order to demonstrate their efficiency. Principally, various techniques, commonly used to monitor landfill surface emissions, can be applied to control biocovers. However, particularly when using engineered materials such as compost substrates, biocovers often feature several altered, specific properties when compared to conventional covers, e.g., respect to gas permeability, physical parameters including water retention capacity and texture, and methane oxidation activity. Therefore, existing measuring methods should be carefully evaluated or even modified prior to application on biocovers. This paper discusses possible strategies to be applied in monitoring biocover functionality. On the basis of experiences derived from investigations and large-scale field trials with compost biocovers in Austria, an assessment approach has been developed. A conceptual draft for monitoring biocover performance and recommendations for practical application are presented.
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Estudios de Evaluación como Asunto , Metano/análisis , Administración de Residuos , Austria , Oxidación-Reducción , Suelo , Microbiología del SueloRESUMEN
A new upgrading process for biogas and landfill gas (LFG) has been designed recently by the authors' institute. The process uses the alkalinity of the fine fraction of bottom ash from municipal solid waste incineration (MSWI) for sorbing CO2 and H2S. Results from process development and optimisation are presented in this paper. It is expected that nearly pure CH4 can be produced for substitution of fossil fuels. Simultaneously, the leachability of MSWI bottom ash is clearly reduced.
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Gases , Anaerobiosis , Proyectos PilotoRESUMEN
Fourier transform infrared (FTIR) spectroscopy combined with multivariate data analysis is under development as a method to classify waste materials. The chemical composition of the sample is reflected by a series of regions of the infrared spectrum which are used as variables for multivariate data analysis. In this study, separated biowaste collection, mechanically-biologically treated waste (MBT-waste), and old landfill materials were collected to provide materials representing different stages of decomposition. A total of 819 FTIR absorbance spectra were recorded. Principal component analyses (PCA) were performed followed by soft independent modeling of class analogy (SIMCA) for classification of waste materials. Strong classification occurred for an analysis where spectral carbonate regions were included, and for another analysis when they were not. The SIMCA model enabled the differentiation and the classification of unknown samples according to the three categories in both cases. The classification methods developed here provide an assessment tool that regulatory authorities may wish to explore when assessing whether a treated waste from an uncertain process can be classed as compost or MBT-waste.
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Residuos/clasificación , Modelos Teóricos , Análisis Multivariante , Análisis de Componente Principal , Espectroscopía Infrarroja por Transformada de Fourier , Residuos/análisisRESUMEN
Disposal of untreated municipal solid waste leads to gaseous emissions as well as liquid degradation products. In situ aeration is an emerging means for remediation of abandoned landfills. It aims at an accelerated mineralization and stabilization of waste organic matter and thus reduces significantly the emission potential of the site. In order to prove the success of the technique, evaluation of the biological stability of the aerated material has been suggested. Fourier Transform Infrared Spectroscopy (FT-IR) provides comprehensive information on the chemical composition of solid waste samples. Different stages of organic matter degradation are reflected by changes in the infrared spectral pattern. In the present study the feasibility of applying FT-IR for assessment of the stability of waste material derived from abandoned landfills and for in situ aeration process control was investigated. Waste samples derived in the course of pilot-scale and lab-scale aeration experiments were characterized by FT-IR (4000-400 cm(-1), KBr-technique, transmission mode) and a set of conventional parameters describing biological stability. The occurrence of distinct indicator bands was correlated with chemical and biological waste properties using 206 solid waste samples. Visual spectra interpretation was found to be appropriate in proving a reduced emission potential of initially rather reactive waste (respiration activity over 4 days (RA(4)) > 7 mg O(2) g(-1) DM) during aeration. Furthermore, cluster analysis was applied successfully to differentiate between original and aerated waste samples, even for rather stable material (RA(4) < 7 mg O(2) g(-1) DM), when visual spectra interpretation was limited.
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Eliminación de Residuos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Residuos/análisis , Análisis por Conglomerados , Monitoreo del Ambiente/métodosRESUMEN
INTRODUCTION: The management of patients with a laparostoma due to peritonitis is a challenge for every surgeon and intensivist. The goal of this study was to compare the different treatment strategies for the open abdomen: Abdominal Dressing (AD), the classic V.A.C. therapy (CV) and conventional open therapy (CT). METHODS: Between 2001 and 2005 we identified 62 patients in 4 surgical departments in Austria who had to be treated with a laparostoma due to peritonitis. 27 patients were conventionally treated, 16 with the Classic V.A.C. therapy and 19 patients with V.A.C. abdominal dressing. RESULTS: The mortality was 3/16 (14 %) in the AD group vs. 4/12 (21 %) patients in the CV group and 18/9 (59 %) in conventional therapy. There was no significant difference for survivors in the length of ICU stay: 26.6 +/- 23.0 days in the CT group, 34.6 +/- 30.2 days in the CV group and 38.9 +/- 27.2 days in the AD group. Apache II Score and Mannheimer Peritonitis Score showed no difference between the groups. CONCLUSION: We found a reduction of mortality in the V.A.C. Abdominal Dressing group by approximately 40 % (AD: 14 %, CT: 59 %). Although we could identify a difference in age in our retrospective study we believe that V.A.C. Abdominal Dressing is the important factor for the different clinical outcome. These first results indicate the need for further prospective evaluation of the V.A.C. Abdominal Dressing therapy, to prove if a new standard in the therapy of the open abdomen is created.
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Abdomen/cirugía , Vendajes , Apósitos Oclusivos , Peritonitis/cirugía , Infección de la Herida Quirúrgica/cirugía , APACHE , Desbridamiento , Humanos , Evaluación de Procesos y Resultados en Atención de Salud , Peritonitis/mortalidad , Reoperación , Estudios Retrospectivos , Infección de la Herida Quirúrgica/mortalidad , Análisis de Supervivencia , Técnicas de Sutura , VacioRESUMEN
Emissions from old landfills via leachate and the gas phase are influenced by state and stability of the organic matter in the solid waste and by environmental conditions within the landfill. Remediation of landfills by means of in-situ aeration is one possibility to reduce these emissions. By establishing aerobic conditions, biological processes in the landfill are accelerated. To investigate the effects of this remediation technology, lab-scale experiments with column tests have been carried out. The main goal of the present work is to characterize the changes of the carbon and nitrogen compounds in the aerated solid waste, the leachate and the gas phase under varying conditions. The results demonstrate a clear reduction of emissions and a stabilization of the organic matter. Furthermore, it is shown that both the intensity of aeration and the amount of water affect biological processes to a certain extent. Even when columns were operated under anaerobic conditions after a long running period of aeration, the emissions remained low.
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Contaminantes Atmosféricos/análisis , Eliminación de Residuos/métodos , Contaminantes Químicos del Agua/análisis , Contaminación del Aire/prevención & control , Carbono/análisis , Dióxido de Carbono/análisis , Metano/análisis , Nitratos/análisis , Nitrógeno/análisis , Compuestos de Amonio Cuaternario/análisis , Residuos/análisis , Residuos/clasificaciónRESUMEN
The management of residues from thermal waste treatment is an integral part of waste management systems. The primary goal of managing incineration residues is to prevent any impact on our health or environment caused by unacceptable particulate, gaseous and/or solute emissions. This paper provides insight into the most important measures for putting this requirement into practice. It also offers an overview of the factors and processes affecting these mitigating measures as well as the short- and long-term behavior of residues from thermal waste treatment under different scenarios. General conditions affecting the emission rate of salts and metals are shown as well as factors relevant to mitigating measures or sources of gaseous emissions.
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Contaminación del Aire/prevención & control , Eliminación de Residuos , Arquitectura y Construcción de Instituciones de Salud , Gases , IncineraciónRESUMEN
Partitioning of a series of free amino acids, their derivatives, and homo-oligopeptides in aqueous dextran-PEG two-phase systems and octanol buffer systems was examined at pH values from 2.0 up to 12.5. The pH-dependent partition behavior of free amino acids and peptides in the two-phase systems was compared with that of monofunctional drug-like compounds and found to be clearly different. The differences observed indicate that the information provided by the techniques of partitioning in octanol buffer (log(D)(pH)) and in aqueous two-phase systems, N(CH2), is different. It is suggested that the combination of the two descriptors, log(D) (lipophilicity) and N(CH2) (relative hydrophobicity), may be useful for QSAR analysis of the biological activities involving distribution and/or transport of chemical compounds in biological systems.
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Aminoácidos/química , Lípidos/química , Octanoles/química , Péptidos/química , Tampones (Química) , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
The regulation of transcription of the gene for the cytosolic form of phosphoenolpyruvate carboxykinase (GTP) (PEPCK-C) (4.1.1.32) during diabetes is a complex process that involves a number of regulatory elements in the PEPCK-C gene promoter. The accessory factor 2 (AF2)-binding region that is contained within the glucocorticoid regulatory unit of the PEPCK-C gene promoter (-451 to -353) has been implicated in the action of both insulin and glucocorticoids on PEPCK-C gene transcription. To determine the role of AF2 in these processes, we have generated a mouse model bearing a transgene that contains the PEPCK-C gene promoter with a mutation in the AF2-binding region. This promoter is linked to the structural gene for human growth hormone that is biologically inactive (AF2-2000/hGx). In the absence of the AF2 regulatory element, the transcription of the transgene in the liver is not induced by diabetes but is inhibited by the administration of insulin. There is also a marked reduction in the response of the AF2-2000/hGx gene in the kidney to the administration of glucocorticoids. The AF2-2000/hGx gene in the liver responds normally to a high carbohydrate diet with a marked decrease in gene transcription. This suggests that insulin is not exerting its usual negative effect on the PEPCK-C gene promoter through the AF2 site. In contrast, the response of this transgene to a high fat/carbohydrate-free diet is severely blunted. Our results support a role for the AF2 site in the PEPCK-C gene promoter in the effect of glucocorticoids, but not insulin, on PEPCK-C gene transcription in the liver.
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Diabetes Mellitus Experimental/genética , Regulación Enzimológica de la Expresión Génica/fisiología , Fosfoenolpiruvato Carboxiquinasa (GTP)/genética , Factores de Transcripción/fisiología , Transcripción Genética/fisiología , Animales , Secuencia de Bases , Cartilla de ADN , Ratones , Ratones Transgénicos , Secuencias Reguladoras de Ácidos Nucleicos , TransgenesRESUMEN
BACKGROUND: This study was performed to determine if postoperative serial monitoring of rectal cancer patients can be performed with an immunoscintigraphic imaging test for carcinoembryonic antigen (CEA). It was also of interest to assess whether this test, in combination with standard monitoring procedures used in an intensive surveillance plan, can result in the identification of surgically salvageable patients. STUDY DESIGN: Forty consecutive resected Dukes' B and C rectal cancer patients underwent a prospective, single-institution, surveillance trial of physical examination (including digital rectal examination), endoscopy, CT of the abdomen and pelvis, liver ultrasound, chest x-ray, blood CEA, and CEA immunoscintigraphy with arcitumomab (CEA-Scan, Immunomedics, Morris Plains, NJ) every 6 months for the first 2 years and every 12 months for the next 3 years after initial operation. Outcomes were compared with those from a similar group of 69 patients treated previously at the same institution but without CEA imaging. RESULTS: A total of 219 CEA imaging studies were performed without any significant adverse effects or immune responses, and resulted in lesion sensitivity, specificity, accuracy, and positive and negative predictive values of 94.1%, 97.5%, 97.3%, 76.2%, and 99.5%, respectively. Of the 40 patients, 16 developed 22 surgically confirmed local or distant recurrences, and CEA imaging correctly disclosed 82% of these lesions pre-operatively. All of the patients found to have recurrences had at least one tumor site by CEA imaging; only 6 of 16 had elevated blood CEA titers. On a patient-basis, there was a sensitivity of 100%, a specificity of 79.2%, an accuracy of 87.5%, and positive and negative predictive values of 76.2% and 100%, respectively. The potential therapeutic benefit of serial arcitumomab imaging is suggested by the fact that 6 of 16 patients (37.5%) with recurrence underwent potentially curative second-look operations, compared with 6 of 69 (8.7%) of a comparable population studied at this institution during an earlier 6-year period, using all of the same tests except CEA imaging. None of the patients in this historic control group survived more than 21 months, although the mean survival of the six patients resected for cure in the study population was 35 months (range 11 to 69 months). During 6 years of followup, three of the six re-resected patients eventually died of cancer recurrence, two died from other causes (and were confirmed by necropsy to be tumor-free), and one patient is still free of disease in the sixth year. CEA scanning appeared to be more predictive of recurrence than blood CEA testing or other diagnostic modalities. CONCLUSIONS: Arcitumomab inclusion in intensive surveillance of patients with resected rectal cancer can disclose tumor recurrence at a stage that allowed surgical salvage therapy in 37.5% of the 16 patients with recurrence who had second-look surgery, and in 19% the patients were free of disease during longterm followup. This pilot study suggests that a randomized prospective trial comparing standard surveillance procedures to the use of CEA imaging added thereto should be undertaken.
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Adenocarcinoma/diagnóstico por imagen , Antígeno Carcinoembrionario/análisis , Radioinmunodetección , Neoplasias del Recto/diagnóstico por imagen , Adenocarcinoma/mortalidad , Adenocarcinoma/secundario , Adenocarcinoma/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Ensayos Clínicos como Asunto , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Proyectos Piloto , Valor Predictivo de las Pruebas , Estudios Prospectivos , Neoplasias del Recto/mortalidad , Neoplasias del Recto/cirugía , Sensibilidad y EspecificidadRESUMEN
Partitioning of a variety of organic compounds, the majority of which represent therapeutic drugs, was examined in an aqueous dextran-polyethylene glycol (Dex-PEG) two-phase system containing 0.15 M NaCl in 0.01 M sodium phosphate buffer at pH 7.3 and in an octanol-buffer (0.15 M NaCl in 0.01 M sodium phosphate buffer, pH 7.3) system. The possibility of introducing compounds to be partitioned in an aqueous two-phase system with dimethyl sulfoxide, and the effect of this solvent on the solute partitioning was explored. Relative hydrophobicity of the compounds was estimated and expressed in equivalent numbers of methylene units. Comparison of the results obtained for several subsets of compounds in the octanol-buffer and in aqueous Dex-PEG two-phase systems clearly demonstrates the advantage of aqueous two-phase partitioning for the hydrophobicity measurements over partitioning in octanol-buffer system.
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Compuestos Orgánicos/química , Preparaciones Farmacéuticas/química , Adenosina Trifosfato/química , Calibración , Dimetilsulfóxido/química , Concentración de Iones de Hidrógeno , Compuestos Orgánicos/aislamiento & purificación , Preparaciones Farmacéuticas/aislamiento & purificación , Relación Estructura-Actividad Cuantitativa , Agua/químicaRESUMEN
Anti-CEA-scintigraphy turned out to be very reliable in detecting primary and recurrent colorectal cancer, its overall accuracy being more than 90%. The intraoperative application of this technology should provide similar results when focussing at extrahepatic tumor deposits, for example in lymph nodes, thus allowing accurate staging of the underlying disease. To test this hypothesis we launched the following feasibility study the results of which are compared to those reported in the recent literature. We investigated 20 patients, six with rectum and 14 with colon cancer. 24 hours before surgery they were intravenously given 1 ml of a fab'-fragment-antibody to CEA, labeled with 25 mCi of 99mTc (CEA-Scan). During surgery the radioactivity in lymph glands regional to the tumors was measured and compared to the much lower activity in healthy nodes. For this we used a scintillation probe (C-Trak, Care Wise, Inc., Morgan Hill, CA). All lymph nodes of interest were then excised and submitted to frozen section pathology. In 7 out of 20 cases scintimetry led to an up-staging of the disease. In addition we found metastatic spread to lymph nodes that were basically not regional to the primary tumor (retroperitoneum, renal hilum etc.). Scintimetry can precisely identify even very small tumor deposits. So it leads to accurate staging while surgery is still ongoing. In a further step the concept of sentinel node diagnosis, which is right now being clinically evaluated, may some day be applied in colorectal surgical oncology.
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Adenocarcinoma/secundario , Anticuerpos Monoclonales , Biomarcadores de Tumor/análisis , Antígeno Carcinoembrionario/análisis , Neoplasias del Colon/cirugía , Cuidados Intraoperatorios/métodos , Metástasis Linfática/diagnóstico , Compuestos de Organotecnecio , Radioinmunodetección , Neoplasias del Recto/cirugía , Biopsia del Ganglio Linfático Centinela , Adenocarcinoma/química , Adenocarcinoma/patología , Adenocarcinoma/cirugía , Anciano , Anciano de 80 o más Años , Animales , Neoplasias del Colon/química , Neoplasias del Colon/patología , Estudios de Factibilidad , Femenino , Humanos , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/secundario , Escisión del Ganglio Linfático , Masculino , Ratones , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Peritoneales/diagnóstico por imagen , Neoplasias Peritoneales/secundario , Estudios Prospectivos , Radioinmunodetección/instrumentación , Radiofármacos , Neoplasias del Recto/química , Neoplasias del Recto/patología , TecnecioRESUMEN
For the European X-ray multi-mirror (XMM) satellite mission and the German X-ray satellite ABRIXAS, fully depleted pn-CCDs have been fabricated, enabling high-speed low-noise position-resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm(2). At 150 K it has a noise of 4 e(-) r.m.s., with a readout time of the total focal plane array of 4 ms. The maximum count rate for single-photon counting was 10(5) counts s(-1) under flat-field conditions. In the integration mode more than 10(9) counts s(-1) can be detected at 6 keV. Its position resolution is of the order of 100 micro m. The quantum efficiency is higher than 90% from carbon K X-rays (277 eV) up to 10 keV. New cylindrical silicon drift detectors have been designed, fabricated and tested. They comprise an integrated on-chip amplifier system with continuous reset, on-chip voltage divider, electron accumulation layer stabilizer, large area, homogeneous radiation entrance window and a drain for surface-generated leakage current. At count rates as high as 2 x 10(6) counts cm(-2) s(-1), they still show excellent spectroscopic behaviour at room-temperature operation in single-photon detection mode. The energy resolution at room temperature is 220 eV at 6 keV X-ray energy and 140 eV at 253 K, being achieved with Peltier coolers. These systems were operated at synchrotron light sources (ESRF, HASYLAB and NLS) as X-ray fluorescence spectrometers in scanning electron microscopes and as ultra low noise photodiodes. The operation of a multi-channel silicon drift detector system is already foreseen at synchrotron light sources for X-ray holography experiments. All systems are fabricated in planar technology having the detector and amplifiers monolithically integrated on high-resistivity silicon.
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: Originally designed as position-sensitive detectors for particle tracking, silicon drift detectors (SDDs) are now used for high-count rate X-ray spectroscopy, operating close to room temperature. Their low-capacitance read-node concept places them among the fastest high-resolution detector systems. They have been used in a new spectrum of experiments in the wide field of X-ray spectroscopy: fluorescent analysis, diffractometry, materials analysis, and synchrotron experiments such as X-ray holography and element imaging in scanning electron microscopes. The fact that the detector system can be used at room temperature with good spectroscopic performance and at -10 degrees C with excellent energy resolution, avoiding liquid nitrogen for cooling and high-quality vacuum, guarantees a large variety of new applications, independent of the laboratory environment. A brief description of the device principles is followed by basics on low noise amplification. The performance results of a complete detector system are presented as well as some dedicated applications already realized, including use in a surface mapping instrument and use of a "mini-spectrometer" for the analysis of works of art. Fully depleted pn-charge-coupled devices (pn-CCDs) have been fabricated for the European X-ray Multi-Mirror mission (XMM) and the German X-ray satellite ABRIXAS, enabling high-speed, low-noise, position-resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm2. At -70 degrees C it has a noise of 4 e- rms, with a readout time of the total focal plane array of 4 msec. The maximum count rate for single photon counting was 10(5) cps under flat field conditions. In the integration mode, more than 10(9) cps can be detected at 6 keV. Its position resolution is on the order of 100 µm. The quantum efficiency is higher than 90%, ranging from carbon K X-rays (277 eV) up to 10 keV.
RESUMEN
Anti-CEA-scintigraphy turned out very reliable in detecting primary and recurrent colorectal cancer, its overall accuracy being more than 90 p.c. The intraoperative application of this technology should provide similar results when focussing at extrahepatic tumor deposits, for example in lymph nodes, thus allowing accurate staging of the underlying disease. To test this hypothesis we lauched the following feasibility-study the results of which are compared to those reported in the recent literature. We investigated 20 patients-six with rectum-, 14 with colon cancer, 24 hours before surgery they were intravenously given 1 ml of an fab-fragment-antibody to CEA, labeled with 25mCi of 99mTc (CEA-Scan). During surgery the radioactivity in lymph glands regionary for the tumors was measured and compared to the-much lower-activity in healthy nodes. For this we used a scintillation-probe (C-Trak). All lymph nodes of interest were-then excised and submitted to frozen section pathology. In 7/20 cases scintimetry led to an up-staging of the disease. In addition we found metastatic spread to lymph nodes that were basically not regionary for the primary tumor. Our results are confirmed by those of other investigators. Scintimetry can precisely identify even very small tumor deposits. So it leads to accurate staging when surgery is still on-going. In a next step the concept of sentinel-node-diagnosis, which is right now being clinically evaluated, may be applied is colorectal surgical oncology.