Simulation of 3d Ising spin glass model using three replicas: study of Binder cumulants

We have carried out numerical simulations of the three-dimensional Ising spin glass model with first neighbour Gaussian couplings using three replicas for each sample of couplings. We have paid special attention to the measure of two types of Binder cumulant that can be constructed from the three possible overlaps between the replicas. We obtain new information about the possible phase transition and perform an initial analysis of the ultrametricity issue.Comment: 14 pages and 7 figures, available at http://chimera.roma1.infn.it/index_papers_complex.htm

Temperature management during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy

In addition to attaining complete or near complete cytoreduction, the instillation of select heated chemotherapeutic agents into the abdominal cavity has offered a chance for cure or longer survival inpatients with peritoneal surface malignancies. While the heating of chemotherapeutic agents enhances cytotoxicity, the resulting systemic hyperthermia has been associated with an increased risk of severe hyperthermia and its associated complications. Factors that have been associated with an increased risk of severe hyperthermia include intraoperative blood transfusions and longer perfusion duration. However, the development of severe hyperthermia still remains largely unpredictable. Thus, at several institutions, cooling protocols are employed during cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Cooling protocols for CRS-HIPEC are not standardized and may be associated with episodes of severe hyperthermia or alternatively hypothermia. In theory, excessive cooling could result in a decreased effectiveness of the intraperitoneal chemotherapeutic agents. This presumption has been supported by a recent study of 214 adults undergoing CRS-HIPEC, where failure to attain a temperature of 38° C at the end of chemo-perfusion was associated with worse survival. Although not statistically significant, failure to maintain a temperature of 38° C for at least 30 minutes was associated with worse survival. Although studies are limited in this regard, the importance of maintaining a steady state of temperature during the hyperthermic phase of intraperitoneal chemotherapy administration cannot be disregarded. The following article describes the processes and physiological mechanisms responsible for hyperthermia during CRS-HIPEC. The challenges associated with temperature management during CRS-HIPEC and methods to avoid severe hypothermia and hyperthermia are also described

Anesthesia Options and the Recurrence of Cancer: What We Know so Far?

Surgery is a critical period in the survival of patients with cancer. While resective surgery of primary tumors has shown to prolong the life of these patients, it can also promote mechanisms associated with metastatic progression. During surgery, patients require general and sometimes local anesthetics that also modulate mechanisms that can favor or reduce metastasis. In this narrative review, we summarized the evidence about the impact of local, regional and general anesthesia on metastatic mechanisms and the survival of patients. The available evidence suggests that cancer recurrence is not significantly impacted by neither regional anesthesia nor volatile or total intravenous anesthesia

Efficient methodology for 3D statistical reconstruction of high resolution coplanar PET/CT scanner

Proceeding of: 2008 IEEE Nuclear Science Symposium Conference Record (NSS '08), Dresden, Germany, 19-25 Oct. 2008A fully 3D statistical image reconstruction algorithm has been developed for a high-resolution coplanar PETtCT scanner based on rotating planar PET detectors. The system matrix has been modeled with custom Monte Carlo techniques optimized for the specific scanner architecture. The system model includes positron range, non-colinearity of gamma rays and crystal interaction modelling with attenuation and Compton scattering effects. Only 0.21 % of the system matrix columns are modeled in detail, obtaining the rest of the values with axial and transaxial voxel-driven symmetries. The iterative algorithm is a fully 3D approach, regularized with the anatomical registered image using a novel version of the minimum cross entropy (MXE) scheme, and accelerated employing ordered subsets. The proposed method has been shown to produce images with superior quality than 3D hybrid (FORE+2D-OSEM) algorithms applied on synthetic GATE data, as well as on real small animal acquisitionsThis work has been partly funded by the CDTEAM project and CENIT programme (Spanish Ministry of Industry), EMIL (ED Network of Excellence), CIBER CB07/09/0031 and RETIC-RECAVA (Spanish Ministry of Health) and TEC2007-64731/TCM(Spanish Ministry of Education and Science

Digital timing in positron emission tomography

Proceeding of: 2006 IEEE Nuclear Science Symposium Conference Record, San Diego, CA, Oct. 29 - Nov. 1, 2006Positron emission tomography (PET) requires accurate timing of events in order to properly discriminate between coincident and non-coincident events. The traditional solution to timing is based on custom ASIC designs, whose cost may not be justified in the design of an experimental small animal PET scanner. The new generation of PET scanners introduces the idea of continuous sampling of the detected scintillation pulse, in substitution of the event triggered acquisition systems. This approach enables new options to timing based on digital processing of the sampled pulse signal. This work proposes a time stamping algorithm based on the optically matched filter and compares the potential performance benefits of this approach versus other FIR filter designs, some of which have been already implemented by different authors. Results show that time resolution of the timestamp may be as 1 ns without the need of expensive high-speed converters when the proper processing is applied.This work has been partially funded by the Spanish Ministry of Culture and Science through the FPU grant program as well as projects TEC2004-07052-C02-02 and PI052204.

Modeling the acquisition front-end in high resolution gamma-ray imaging

The availability of synthetic realistic data eases design optimization, algorithm evaluation and verification of any digital system where a significant amount of digital signal processing is performed. The evolution of positron emission tomography cameras towards continuous sampling of individual position-sensitive photomultiplier anodes with processing algorithms implemented on digital programmable logic devices creates a new framework where new approaches to the γ-event detection are possible. We have developed a system model of the acquisition chain, including multi-layer phoswich, photomultiplier, front-end analog electronics, data acquisition and digital processing. This processing includes estimation algorithms for the most relevant event parameters: energy, layer-of-interaction, time picking-off and event location. The selected simulation platform couples gently to digital hardware simulation tools, in such a way that implemented models may generate real-like stimuli for the digital system under development. The modeling of the whole front-end electronics enables deeper understanding and tuning of different system trade-offs and provides a rapid and soft transition between specification and hardware developmentPublicad

Modeling the acquisition front-end in high resolution gamma-ray imaging

Proceeding of: 2004 IEEE Nuclear Science Symposium Conference Record, Rome, Italy, 16-22 October 2004The availability of synthetic realistic data enables design optimization, algorithm evaluation and verification of any digital system where a significant amount of digital signal processing is performed. The evolution of positron emission tomography cameras towards continuous sampling of individual position-sensitive photomultiplier anodes with processing algorithms implemented on digital programmable logic devices creates a new framework where new approaches to the γ-event detection are possible. We have developed a system model of the acquisition chain, including multi-layer phoswich, photomultiplier, front-end analog electronics, data acquisition and data processing. This processing includes estimation algorithms for the most relevant event parameters: energy, layerof- interaction, time picking-off and event location. The selected simulation platform couples gently to digital hardware simulation tools, in such a way that implemented models may generate reallike stimuli for the digital system under development. The modeling of the whole front-end electronics enables deeper understanding and tuning of different system trade-offs and provides a rapid and soft transition between specification and hardware development

Multipurpose Monte Carlo simulator for photon transport in turbid media

Proceeding of: 2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), Orlando, Florida, 25-31 October 2009Monte Carlo methods provide a flexible and rigorous solution to the problem of light transport in turbid media, which enable approaching complex geometries for a closed analytical solution is not feasible. The simulator implements local rules of propagation in the form of probability density functions that depend on the local optical properties of the tissue. This work presents a flexible simulator that can be applied in multiple applications related to optical tomography. In particular, unlike previous codes, the simulator explicitly supports fluorescent-tissues and variance reduction and code parallelization techniques are implemented in order to speed up the execution with fluorochrome-labelled agents. The simulator is validated with simple geometries for which an analytical solution exists, as well as with an experimental polyester resin based optical phantom.This work was supported in part by the Ministry of Science and Innovation under projects TEC2008-06715 and TEC2007-64731/TCM and by the EU’s 7th Frame Programme under contract HEALTH-F5-2008-20179

A Very di-Still-ed Diagnosis- Adult-Onset Still’s Disease Presenting in a Middle-Aged Hispanic Patient

Background: Adult-Onset Still’s Disease (AOSD) is a systemic inflammatory disorder characterized by daily high fevers, arthritis, evanescent rash, and leukocytosis (1). Patients can present without typical manifestations and pose a challenging differential. We present a case of a 52-year-old gentleman with a one-year history of recurring fever, lymphadenopathy, and weight loss diagnosed with AOSD. This case highlights the diagnostic challenge that AOSD poses and the strategies to help aid in the diagnosis. Case Presentation: A 52-year-old gentleman presented to the ED for a 2-week history of fever associated with chills and bone pain. He reported that he has been having intermittent fever, weight loss, night sweats, and rash for the past year with prior workup being unrevealing. He endorsed swollen glands and fatigue but denied productive cough, chest pain, gastrointestinal, urinary, or neurological symptoms. On physical examination, the patient was febrile at 101.9 deg F, tachycardic 121 BPM, and RR 21 br/min. He appeared cachexic, with dry oral mucosa, palpable lymphadenopathy, and bilateral knee tenderness. Laboratories were remarkable for WBC 22.3 th/mm3, hemoglobin 11.1 gm/dL, platelet 513 th/mm3, sedimentation rate 120 mm/h, CRP 23 mg/dL, lactic acid 0.89 mmol/L, ferritin level 28,595.9 ng/mL, and LDH 603 IU/L. Peripheral smear revealed reactive neutrophilic leukocytosis. Infectious etiology, including SARS Covid-19PCR, HIV, blood cultures, lumbar puncture with CSF analysis, and QuantiFERON gold were negative. Autoimmune workup was unrevealing. CT Chest/Abdomen demonstrated moderate pleural effusions and reactive bilateral hilar, mediastinal, and retroperitoneal lymphadenopathy, and hepatomegaly. CT-guided biopsy of the left inguinal lymph node showed benign follicles with mixed B and T cells. Flow cytometry showed increased granulocytes and eosinophils without immunophenotypic abnormalities to suggest hematologic malignancy. After excluding infectious and malignant causes, rheumatology was consulted. Based on symptomatology, laboratory, and radiographic findings, a diagnosis of AOSD was entertained. Yamaguchi\u27s criteria supported the diagnosis with four major and four minor criteria met (2). The patient was started on prednisone 1 mg/kg with excellent response. Conclusion: AOSD is a diagnosis of exclusion, and the appropriate clinical scenario should warrant further investigation. AOSD should be in the differential after careful workup and excluding infectious etiology, malignancy, and other connective tissue diseases