Recomendaciones para la recuperación posquirúrgica optimizada en columna (REPOC) / Recommendations for enhanced post-surgical recovery in the spine (REPOC)

Introducción y objetivos: La recuperación posquirúrgica optimizada en columna (REPOC) constituye un enfoque multimodal, basado en la evidencia científica disponible, que consigue una mejora eficaz de la funcionalidad fisiológica del paciente, reduce el dolor e incluso disminuye los costes hospitalarios. El objetivo de este trabajo es proponer unos estándares para la aplicación de la REPOC a la cirugía de fusión lumbar. Métodos: Se constituyó ad hoc un grupo multidisciplinario de expertos que revisaron la evidencia disponible y plantearon recomendaciones consensuadas para la artrodesis lumbar, utilizando el sistema Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Resultados: Se seleccionaron 23 recomendaciones en las fases preoperatoria, intraoperatoria y postoperatoria de la intervención quirúrgica. También se elaboró una lista de 29 ítems para la aplicación de la REPOC en cirugía de columna. Conclusiones: Este listado de recomendaciones facilitará la implementación del enfoque REPOC como herramienta segura y eficaz para la reducción de los eventos adversos en nuestro entorno.(AU)

Introduction/objectives: Enhanced recovery after surgery (ERAS) constitutes a multimodal approach, based on available scientific evidence, that achieves better patient's functionality, reduces pain, and even lowers financial costs. The present consensus statement proposes the standards for the implementation of ERAS programs to lumbar fusion surgery, a meant benchmark we call REPOC. Methodology: A multidisciplinary group of experts was set up ad hoc to review consensus recommendations for lumbar arthrodesis, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Results: As a result, 23 recommendations were selected throughout the preoperative, intraoperative, and postoperative phases of the surgical procedure. A 29-item checklist was also drawn up to implement REPOC protocols in spinal surgeries. Conclusions: This list of recommendations will facilitate the implementation of this multimodal approach as a safe and effective tool for reducing adverse events in our environment.(AU)

[Translated article] Recommendations for enhanced post-surgical recovery in the spine (REPOC) / Recomendaciones para la recuperación posquirúrgica optimizada en columna (REPOC)

Introducción y objetivos: La recuperación posquirúrgica optimizada en columna (REPOC) constituye un enfoque multimodal, basado en la evidencia científica disponible, que consigue una mejora eficaz de la funcionalidad fisiológica del paciente, reduce el dolor e incluso disminuye los costes hospitalarios. El objetivo de este trabajo es proponer unos estándares para la aplicación de la REPOC a la cirugía de fusión lumbar. Métodos: Se constituyó ad hoc un grupo multidisciplinario de expertos que revisaron la evidencia disponible y plantearon recomendaciones consensuadas para la artrodesis lumbar, utilizando el sistema Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Resultados: Se seleccionaron 23 recomendaciones en las fases preoperatoria, intraoperatoria y postoperatoria de la intervención quirúrgica. También se elaboró una lista de 29 ítems para la aplicación de la REPOC en cirugía de columna. Conclusiones: Este listado de recomendaciones facilitará la implementación del enfoque REPOC como herramienta segura y eficaz para la reducción de los eventos adversos en nuestro entorno.(AU)

Introduction/objectives: Enhanced recovery after surgery (ERAS) constitutes a multimodal approach, based on available scientific evidence, that achieves better patient's functionality, reduces pain, and even lowers financial costs. The present consensus statement proposes the standards for the implementation of ERAS programs to lumbar fusion surgery, a meant benchmark we call REPOC. Methodology: A multidisciplinary group of experts was set up ad hoc to review consensus recommendations for lumbar arthrodesis, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. Results: As a result, 23 recommendations were selected throughout the preoperative, intraoperative, and postoperative phases of the surgical procedure. A 29-item checklist was also drawn up to implement REPOC protocols in spinal surgeries. Conclusions: This list of recommendations will facilitate the implementation of this multimodal approach as a safe and effective tool for reducing adverse events in our environment.(AU)

A proof-of-concept of cross-luminescent metascintillators: testing results on a BGO:BaF2metapixel.

Objective: Time-of-flight positron emission tomography (PET) is the next frontier in improving the effective sensitivity. To achieve superior timing for time-of-flight PET, combined with high detection efficiency and cost-effectiveness, we have studied the applicability of BaF2 in metascintillators driven by the timing of cross-luminescence photon production.Approach: Based on previous simulation studies of energy sharing and analytic multi-exponential scintillation pulse, as well as sensitivity characteristics, we have experimentally tested a pixel of 3 × 3 × 15 mm3 based on 300µm BGO and 300µm BaF2 layers. To harness the deep ultraviolet cross-luminescent light component, which carries improved timing, we use the FBK VUV SiPM. Metascintillator energy sharing is addressed through a double integration approach.Main results: We reach an energy resolution of 22%, comparable to an 18% resolution of simple BGO pixels using the same readout, through the optimized use of the integrals of the metascintillator pulse in energy sharing calculation. We measure the energy sharing extent of each pulse with a resolution of 25% and demonstrate that experimental and simulation results agree well. Based on the energy sharing, a timewalk correction is applied, exhibiting significant improvements for both the coincidence time resolution (CTR) and the shape of the timing histogram. We reach 242 ps CTR for the entire photopeak, while for a subset of 13% of the most shared events, the CTR value improves to 108 ps, comparable to the 3 × 3 × 5 mm3 LYSO:Ce:Ca reference crystal.Significance: While we are considering different ways to improve further these results, this proof-of-concept demonstrates the applicability of cross-luminescence for metascintillator designs through the application of VUV compatible SiPM coupling, and easily implementable digital algorithms. This is the first test of BaF2-based metascintillators of sufficient stoppng power to be included in a PET scanner, demonstrating the industrial applicability of such cross-luminescent metascintillators.

Recommendations for enhanced post-surgical recovery in the spine (REPOC). / Recomendaciones para la recuperación posquirúrgica optimizada en columna (REPOC).

INTRODUCTION/OBJECTIVES: Enhanced recovery after surgery (ERAS) constitutes a multimodal approach, based on available scientific evidence, that achieves better patient's functionality, reduces pain, and even lowers financial costs. The present consensus statement proposes the standards for the implementation of ERAS programs to lumbar fusion surgery, a meant benchmark we call REPOC. METHODOLOGY: A multidisciplinary group of experts was set up ad hoc to review consensus recommendations for lumbar arthrodesis, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. RESULTS: As a result, 23 recommendations were selected throughout the preoperative, intraoperative, and postoperative phases of the surgical procedure. A 29-item checklist was also drawn up to implement REPOC protocols in spinal surgeries. CONCLUSIONS: This list of recommendations will facilitate the implementation of this multimodal approach as a safe and effective tool for reducing adverse events in our environment.

[Translated article] Recommendations for enhanced post-surgical recovery in the spine (REPOC).

INTRODUCTION/OBJECTIVES: Enhanced recovery after surgery (ERAS) constitutes a multimodal approach, based on available scientific evidence, that achieves better patient's functionality, reduces pain, and even lowers financial costs. The present consensus statement proposes the standards for the implementation of ERAS programmes to lumbar fusion surgery, a meant benchmark we call REPOC. METHODOLOGY: A multidisciplinary group of experts was set up ad hoc to review consensus recommendations for lumbar arthrodesis, using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system. RESULTS: As a result, 23 recommendations were selected throughout the preoperative, intraoperative, and postoperative phases of the surgical procedure. A 29-item checklist was also drawn up to implement REPOC protocols in spinal surgeries. CONCLUSIONS: This list of recommendations will facilitate the implementation of this multimodal approach as a safe and effective tool for reducing adverse events in our environment.

Position estimation using neural networks in semi-monolithic PET detectors.

Objective. The goal of this work is to experimentally compare the 3D spatial and energy resolution of a semi-monolithic detector suitable for total-body positron emission tomography (TB-PET) scanners using different surface crystal treatments and silicon photomultiplier (SiPM) models.Approach. An array of 1 × 8 lutetium yttrium oxyorthosilicate (LYSO) slabs of 25.8 × 3.1 × 20 mm3separated with Enhanced Specular Reflector (ESR) was coupled to an array of 8 × 8 SiPMs. Three different treatments for the crystal were evaluated: ESR + RR + B,with lateral faces black (B) painted and a retroreflector (RR) layer added to the top face; ESR +RR, with lateral faces covered with ESR and a RR layer on the top face and; All ESR, with lateral and top sides with ESR. Additionally, two SiPM array models from Hamamatsu Photonics belonging to the series S13361-3050AE-08 (S13) and S14161-3050AS-08 (S14) have been compared. Coincidence data was experimentally acquired using a22Na point source, a pinhole collimator, a reference detector and moving the detector under study in 1 mm steps in thex- andDOI- directions. The spatial performance was evaluated by implementing a neural network (NN) technique for the impact position estimation in thex- (monolithic) andDOIdirections.Results. Energy resolution values of 16 ± 1%, 11 ± 1%, 16 ± 1%, 15 ± 1%, and 13 ± 1% were obtained for theS13-ESR + B + RR,S13-AllESR,S14-ESR + B + RR,S14-ESR + RR,andS14-AllESR, respectively. Regarding positioning accuracy, mean average error of 1.1 ± 0.5, 1.3 ± 0.5 and 1.3 ± 0.5 were estimated for thex- direction and 1.7 ± 0.8, 2.0 ± 0.9 and 2.2 ± 1.0 for theDOI- direction, for the ESR + B + RR, ESR + RR and All ESR cases, respectively, regardless of the SiPM model.Significance. Overall, the obtained results show that the proposed semi-monolithic detectors are good candidates for building TB-PET scanners.

Beamforming for large-area scan and improved SNR in array-based photoacoustic microscopy.

Beamforming enhances the performance of array-based photoacoustic microscopy (PAM) systems for large-area scan. In this study, we quantify the imaging performance of a large field-of-view optical-resolution photoacoustic-microscopy system using an phased-array detector. The system combines a low-cost pulsed-laser diode with a 128-element linear ultrasound probe. Signal-to-noise ratio (SNR) and generalized contrast-to-noise ratio (gCNR) are quantified using the phased-array detector and applying three beamforming strategies: a no-beamforming method equivalent to a single-element flat transducer, a fixed focus beamforming method that mimics a single-element focused transducer, and a dynamic focus beamforming using a delay-and-sum (DAS) algorithm. The imaging capabilities of the system are demonstrated generating high-resolution images of tissue-mimicking phantoms containing sub-millimetre ink tubes and an ex vivo rabbit's ear. The results show that dynamic focus DAS beamforming increases and homogenizes SNR along 1-cm2 images, reaching values up to 15 dB compared to an unfocused detector and up to 30 dB compared to out-of-focus regions of the fixed focus configuration. Moreover, the obtained values of gCNR using the DAS beamformer indicate an excellent target visibility, both on phantoms and ex vivo. This strategy makes it possible to scan larger surfaces compared to standard configurations using single-element detectors, paving the way for advanced array-based PAM systems.

PADC nuclear track detector for ion spectroscopy in laser-plasma acceleration.

The transparent polymer polyallyl-diglycol-carbonate (PADC), also known as CR-39, is widely used as detector for heavy charged particles at low fluence. It allows for detection of single protons and ions via formation of microscopic tracks after etching in NaOH or KOH solutions. PADC combines a high sensitivity and high specificity with inertness towards electromagnetic noise. Present fields of application include laser-ion acceleration, inertial confinement fusion, radiobiological studies with cell cultures, and dosimetry of nuclear fragments in particle therapy. These require precise knowledge of the energy-dependent response of PADC to different ion species. We present calibration data for a new type of detector material, Radosys RS39, to protons (0.2-3 MeV) and carbon ions (0.6-12 MeV). RS39 is less sensitive to protons than other types of PADC. Its response to carbon ions, however, is similar to other materials. Our data indicate that RS39 allows for measuring carbon ion energies up to 10 MeV only from the track diameters. In addition, it can be used for discrimination between protons and carbon ions in a single etching process.

The sacral chordoma margin.

OBJECTIVE: Aim of the manuscript is to discuss how to improve margins in sacral chordoma. BACKGROUND: Chordoma is a rare neoplasm, arising in half cases from the sacrum, with reported local failure in >50% after surgery. METHODS: A multidisciplinary meeting of the "Chordoma Global Consensus Group" was held in Milan in 2017, focusing on challenges in defining and achieving optimal margins in chordoma with respect to surgery, definitive particle radiation therapy (RT) and medical therapies. This review aims to report on the outcome of the consensus meeting and to provide a summary of the most recent evidence in this field. Possible new ways forward, including on-going international clinical studies, are discussed. RESULTS: En-bloc tumor-sacrum resection is the cornerstone of treatment of primary sacral chordoma, aiming to achieve negative microscopic margins. Radical definitive particle therapy seems to offer a similar outcome compared to surgery, although confirmation in comparative trials is lacking; besides there is still a certain degree of technical variability across institutions, corresponding to different fields of treatment and different tumor coverage. To address some of these questions, a prospective, randomized international study comparing surgery versus definitive high-dose RT is ongoing. Available data do not support the routine use of any medical therapy as (neo)adjuvant/cytoreductive treatment. CONCLUSION: Given the significant influence of margins status on local control in patients with primary localized sacral chordoma, the clear definition of adequate margins and a standard local approach across institutions for both surgery and particle RT is vital for improving the management of these patients.

Simulation Study for Designing a Dedicated Cardiac TOF-PET System.

The development of dedicated positron emission tomography scanners is an active area of research, especially aiming at the improvement of lesion detection and in support of cancer treatment and management. Recently, dedicated Positron Emission Tomography (PET) systems with different configurations for specific organs have been developed for improving detection effectiveness. Open geometries are always subject to distortion and artifacts in the reconstructed images. Therefore, the aim of this work is to determine the optimal geometry for a novel cardiac PET system that will be developed by our team, and determine the time resolution needed to achieve reasonable image quality for the chosen geometry. The proposed geometries consist of 36 modules. These modules are arranged in two sets of two plates, each one with different configurations. We performed Monte Carlo simulations with different TOF resolutions, in order to test the image quality improvement in each case. Our results show, as expected, that increasing TOF resolution reduces distortion and artifact effects. We can conclude that a TOF resolution of the order of 200 ps is needed to reduce the artifacts, to acceptable levels, generated in the simulated cardiac-PET open geometries.

Prevention of meconium obstruction in very low birth weight preterm infants. / Prevención de la obstrucción meconial en recién nacidos prematuros de muy bajo peso.

INTRODUCTION: Delayed meconium expulsion is a cause of bowel obstruction in the extremely premature newborn (<28 WGE) weighing less than 1500g at birth. OBJECTIVE: To evaluate the efficacy of conservative treatment in the prevention of meconium obstruction in very-low-birt- weight preterm infants. METHOD: Descriptive and retrospective study performed at the Neonatal Intensive Care Unit of a tertiary level hospital. All very-low-birth-weight preterm infants who were born during the study period, from August 2016 to January 2017, and who had meconium obstruction were included. RESULTS: A sample of 42 newborn infants was obtained. Regarding the expulsion of meconium, 57.1% of the sample spontaneously ejected meconium, while 42.9% received different treatments. Of these, 72.2% were treated with saline enemas, 16% with acetylcysteine enemas, 16% with Gastrografin® and none required surgical treatment. CONCLUSION: Conservative treatment seems to be an effective therapeutic measure for the prevention of meconium obstruction in very-low-birth-weight preterm infants since it achieved the expulsion of meconium without having to apply surgical treatment.

Spectral characterization of laser-accelerated protons with CR-39 nuclear track detector.

CR-39 nuclear track material is frequently used for the detection of protons accelerated in laser-plasma interactions. The measurement of track densities allows for determination of particle angular distributions, and information on the kinetic energy can be obtained by the use of passive absorbers. We present a precise method of measuring spectral distributions of laser-accelerated protons in a single etching and analysis process. We make use of a one-to-one relation between proton energy and track size and present a precise calibration based on monoenergetic particle beams. While this relation is limited to proton energies below 1 MeV, we show that the range of spectral measurements can be significantly extended by simultaneous use of absorbers of suitable thicknesses. Examples from laser-plasma interactions are presented, and quantitative results on proton energies and particle numbers are compared to those obtained from a time-of-flight detector. The spectrum end points of continuous energy distributions have been determined with both detector types and coincide within 50-100 keV.

Surgery for metastatic spine tumors in the elderly. Advanced age is not a contraindication to surgery!

BACKGROUND: With recent advances in oncologic treatments, there has been an increase in patient survival rates and concurrently an increase in the number of incidence of symptomatic spinal metastases. Because elderly patients are a substantial part of the oncology population, their types of treatment as well as the possible impact their treatment will have on healthcare resources need to be further examined. PURPOSE: We studied whether age has a significant influence on quality of life and survival in surgical interventions for spinal metastases. STUDY DESIGN: We used data from a multicenter prospective study by the Global Spine Tumor Study Group (GSTSG). This GSTSG study involved 1,266 patients who were admitted for surgical treatments of symptomatic spinal metastases at 22 spinal centers from different countries and followed up for 2 years after surgery. PATIENT SAMPLE: There were 1,266 patients recruited between March 2001 and October 2014. OUTCOME MEASURES: Patient demographics were collected along with outcome measures, including European Quality of Life-5 Dimensions (EQ-5D), neurologic functions, complications, and survival rates. METHODS: We realized a multicenter prospective study of 1,266 patients admitted for surgical treatment of symptomatic spinal metastases. They were divided and studied into three different age groups: <70, 70-80, and >80 years. RESULTS: Despite a lack of statistical difference in American Society of Anesthesiologists (ASA) score, Frankel neurologic score, or Karnofsky functional score at presentation, patients >80 years were more likely to undergo emergency surgery and palliative procedures compared with younger patients. Postoperative complications were more common in the oldest age group (33.3% in the >80, 23.9% in the 70-80, and 17.9% for patients <70 years, p=.004). EQ-5D improved in all groups, but survival expectancy was significantly longer in patients <70 years old (p=.02). Furthermore, neurologic recovery after surgery was lower in patients >80 years old. CONCLUSIONS: Surgeons should not be biased against operating elderly patients. Although survival rates and neurologic improvements in the elderly patients are lower than for younger patients, operating the elderly is compounded by the fact that they undergo more emergency and palliative procedures, despite good ASA scores and functional status. Age in itself should not be a determinant of whether to operate or not, and operations should not be avoided in the elderly when indicated.

Seguridad a largo plazo en el donante vivo para trasplante renal pediátrico. Estudio prospectivo, unicéntrico / Long-term safety in living kidney donors for paediatric transplantation. Single-centre prospective study

Introducción: Existe evidencia suficiente sobre la seguridad a corto plazo en el donante vivo tras el trasplante renal. Sin embargo, las complicaciones a largo plazo continúan siendo un área de estudio en la actualidad, de especial interés en el donante joven. Previamente se han realizado análisis en donantes de edad más avanzada para enfermos renales adultos. Presentamos un estudio de complicaciones a largo plazo en donantes renales para nuestra población pediátrica. Métodos: Estudiamos a largo plazo a los donantes de los 54 trasplantes renales de donante vivo realizados en nuestro servicio desde 1979 hasta junio del 2014. Hemos monitorizado el filtrado glomerular (FG) mediante aclaramiento de creatinina en orina de 24 h, proteinuria en orina de 24 h y el desarrollo de hipertensión arterial (HTA) en los 48 donantes que han presentado un seguimiento mayor de un año. En el análisis de resultados se han incluido tan solo a los 39 pacientes que han sido exclusivamente controlados en nuestro servicio. Resultados: El FG mediante aclaramiento de creatinina fue estable tras su descenso inicial. No se observó proteinuria en ninguno de los casos. Se observó enfermedad renal crónica (ERC) avanzada en un paciente, lo cual supuso una incidencia acumulada del 2%, no describiéndose FG menor de 60mL/min/1,73m2 en ningún otro paciente. La HTA fue diagnosticada en el 25% de los donantes, con tratamiento hipotensor en el 90% de ellos. Conclusiones: El riesgo de ERC y de HTA en donantes renales vivos para receptor pediátrico cuidadosamente monitorizados en su evolución es similar al de la población general por lo que parece tratarse de una técnica segura a corto y largo plazo (AU)

Introduction: There is enough evidence concerning the short-term safety of living donors after kidney transplantation. However, long-term complications continue to be studied, with a particular interest in young donors. Previous studies have been conducted in older donors for adult renal patients. We present a study of long-term complications in kidney donors for our paediatric population. Methods: We carried out a long-term donor study for the 54 living kidney-donor transplantations performed at our department from 1979 to June 2014. We monitored the glomerular filtration rate (GFR) on the basis of 24-hour urine creatinine clearance, 24-hour proteinuria and the development of arterial hypertension in the 48 donors who were followed up for more than one year. Only the 39 patients who were exclusively followed up by our department have been included in the results analysis. Results: GFR through creatinine clearance was stable after an initial decrease. No proteinuria was observed in any of the cases. One patient developed chronic kidney disease (CKD), which resulted in a cumulative incidence of 2%. GFR below 60mL/min/1.73 m2 was not reported in any other patients. Arterial hypertension was diagnosed in 25% of donors, 90% of which were treated with antihypertensives. Conclusions: Risk of CKD and hypertension in living kidney donors for paediatric recipients, who are carefully monitored throughout their evolution, is similar to that of the general population. Therefore, this technique appears to be safe in both the short and long term (AU)

Primary pleomorphic liposarcoma of the spine. Case report and review of the literature.

INTRODUCTION: To describe a single case, the fourth ever reported, of pleomorphic liposarcoma of the spine and to undertake a review of the literature. PRESENTATION OF CASE: A 60 year old male patient had a bilateral lumbosciatica over a 3 month period. Imaging tests revealed a tumor mass in L1-L3 and a fracture in L2. Also, he had a mural thrombus both in the inferior vena cava and the left renal vein. The biopsy revealed a well-differentiated liposarcoma. En bloc resection of the lesion and stabilization was carried out. Due to the condition of the patient (hemodynamic instability, wound dehiscence and infection, and hypoproteinemia), a decision was made not to subject the patient to either radiation therapy or chemotherapy. The patient was subsequently found to suffer from myopathic paraparesis and a surgical wound infection. At three months, liver metastases were evident, as well as a recurrence of the lesion. A venous thrombosis that extended from the lower iliac vein to the right atrium was observed. The patient died from type I hepatorenal syndrome. DISCUSSION: Pleomorphic liposarcoma of the spine is a rare occurrence. En bloc resection with wide margins is the treatment of choice. The use of radiotherapy in the spine is controversial. The role that should be played by chemotherapy is still unclear, although it has been employed in treatments. CONCLUSION: In spite of treatment, these tumors lead to a poor prognosis, with high rates of recurrence, metastasis, and mortality.

Long-term safety in living kidney donors for paediatric transplantation. Single-centre prospective study. / Seguridad a largo plazo en el donante vivo para trasplante renal pediátrico. Estudio prospectivo, unicéntrico.

INTRODUCTION: There is enough evidence concerning the short-term safety of living donors after kidney transplantation. However, long-term complications continue to be studied, with a particular interest in young donors. Previous studies have been conducted in older donors for adult renal patients. We present a study of long-term complications in kidney donors for our paediatric population. METHODS: We carried out a long-term donor study for the 54 living kidney-donor transplantations performed at our department from 1979 to June 2014. We monitored the glomerular filtration rate (GFR) on the basis of 24-hour urine creatinine clearance, 24-hour proteinuria and the development of arterial hypertension in the 48 donors who were followed up for more than one year. Only the 39 patients who were exclusively followed up by our department have been included in the results analysis. RESULTS: GFR through creatinine clearance was stable after an initial decrease. No proteinuria was observed in any of the cases. One patient developed chronic kidney disease (CKD), which resulted in a cumulative incidence of 2%. GFR below 60mL/min/1.73 m2 was not reported in any other patients. Arterial hypertension was diagnosed in 25% of donors, 90% of which were treated with antihypertensives. CONCLUSIONS: Risk of CKD and hypertension in living kidney donors for paediatric recipients, who are carefully monitored throughout their evolution, is similar to that of the general population. Therefore, this technique appears to be safe in both the short and long term.

La enfermedad de Castleman: entidad poco frecuente en pediatría y de presentación variable / Castleman’s disease: a rare entity and variable presentation in children

La enfermedad de Castleman (EC) es un trastorno linfoproliferativo infrecuente. Su etiología es desconocida, pero se cree que en ella pueden estar implicados procesos autoinmunes, inflamaciones crónicas, infecciones e inmunodeficiencias. Afecta a pacientes jóvenes y se diferencian clínicamente dos formas, una localizada, que se presenta como una masa única, asintomática, de buen pronóstico, más prevalente en pediatría, y otra multicéntrica, con afectación sistémica y peor pronóstico. Histológicamente, existen dos variantes: la hialinovascular, que suele corresponder a las formas localizadas, y la de células plasmáticas, que suele ser multicéntrica. La resección es curativa en las formas localizadas; sin embargo, en las formas multicéntricas se ha ensayado multitud de tratamientos sin éxito. Presentamos el caso de un paciente de 7 años de edad con una forma localizada de EC en la región cervical, en la que la resección quirúrgica resultó ser diagnóstica y terapéutica. Tras 2 años de seguimiento, se mantiene asintomático (AU)

Castleman's disease (CD) is an uncommon lymphoproliferative disorder. The etiology is unknown, but autoimmune processes, chronic inflammations, infections and immunodeficiencies are postulated to be involved. CD usually affects young patients and is classified into two clinical groups: a localized variant, the more frequent type in children, presented as a solitary asymptomatic mass, with good prognosis; and the multicentric variant, associated with systemic symptoms and a more aggressive clinical evolution. There are two histological variants, the hyaline-vascular type, which usually appears as localized forms, and the plasma-cell type, which is often multicentric. Resection is curative in localized forms; however, several treatments have been tried in multicentric forms without success. We report the case of a 7-year-old boy with the localized form of CD in the neck, in which the excision was both diagnostic and therapeutic. He remains asymptomatic after 2 years of follow-up (AU)

ALBIRA: a small animal PET∕SPECT∕CT imaging system.

PURPOSE: The authors have developed a trimodal PET∕SPECT∕CT scanner for small animal imaging. The gamma ray subsystems are based on monolithic crystals coupled to multianode photomultiplier tubes (MA-PMTs), while computed tomography (CT) comprises a commercially available microfocus x-ray tube and a CsI scintillator 2D pixelated flat panel x-ray detector. In this study the authors will report on the design and performance evaluation of the multimodal system. METHODS: X-ray transmission measurements are performed based on cone-beam geometry. Individual projections were acquired by rotating the x-ray tube and the 2D flat panel detector, thus making possible a transaxial field of view (FOV) of roughly 80 mm in diameter and an axial FOV of 65 mm for the CT system. The single photon emission computed tomography (SPECT) component has a dual head detector geometry mounted on a rotating gantry. The distance between the SPECT module detectors can be varied in order to optimize specific user requirements, including variable FOV. The positron emission tomography (PET) system is made up of eight compact modules forming an octagon with an axial FOV of 40 mm and a transaxial FOV of 80 mm in diameter. The main CT image quality parameters (spatial resolution and uniformity) have been determined. In the case of the SPECT, the tomographic spatial resolution and system sensitivity have been evaluated with a (99m)Tc solution using single-pinhole and multi-pinhole collimators. PET and SPECT images were reconstructed using three-dimensional (3D) maximum likelihood and ordered subset expectation maximization (MLEM and OSEM) algorithms developed by the authors, whereas the CT images were obtained using a 3D based FBP algorithm. RESULTS: CT spatial resolution was 85 µm while a uniformity of 2.7% was obtained for a water filled phantom at 45 kV. The SPECT spatial resolution was better than 0.8 mm measured with a Derenzo-like phantom for a FOV of 20 mm using a 1-mm pinhole aperture collimator. The full width at half-maximum PET radial spatial resolution at the center of the field of view was 1.55 mm. The SPECT system sensitivity for a FOV of 20 mm and 15% energy window was 700 cps∕MBq (7.8 × 10(-2)%) using a multi-pinhole equipped with five apertures 1 mm in diameter, whereas the PET absolute sensitivity was 2% for a 350-650 keV energy window and a 5 ns timing window. Several animal images are also presented. CONCLUSIONS: The new small animal PET∕SPECT∕CT proposed here exhibits high performance, producing high-quality images suitable for studies with small animals. Monolithic design for PET and SPECT scintillator crystals reduces cost and complexity without significant performance degradation.

Expectation maximization (EM) algorithms using polar symmetries for computed tomography (CT) image reconstruction.

We suggest a symmetric-polar pixellation scheme which makes possible a reduction of the computational cost for expectation maximization (EM) iterative algorithms. The proposed symmetric-polar pixellation allows us to deal with 3D images as a whole problem without dividing the 3D problem into 2D slices approach. Performance evaluation of each approach in terms of stability and image quality is presented. Exhaustive comparisons between all approaches were conducted in a 2D based image reconstruction model. From these 2D approaches, that showing the best performances were finally implemented and evaluated in a 3D based image reconstruction model. Comparison to 3D images reconstructed with FBP is also presented. Although the algorithm is presented in the context of computed tomography (CT) image reconstruction, it can be applied to any other tomographic technique as well, due to the fact that the only requirement is a scanning geometry involving measurements of an object under different projection angles. Real data have been acquired with a small animal (CT) scanner to verify the proposed mathematical description of the CT system.

Design and evaluation of the MAMMI dedicated breast PET.

PURPOSE: A breast dedicated positron emission tomography (PET) scanner has been developed based on monolithic LYSO crystals coupled to position sensitive photomultiplier tubes (PSPMTs). In this study, we describe the design of the PET system and report on its performance evaluation. METHODS: MAMMI is a breast PET scanner based on monolithic LYSO crystals. It consists of 12 compact modules with a transaxial field of view (FOV) of 170 mm in diameter and 40 mm axial FOV that translates to cover up to 170 mm. The patient lies down in a prone position that facilitates maximum breast elongation. Quantitative performance analysis of the calculated method for the attenuation correction specifically developed for MAMMI, and based on PET image segmentation, has also been conducted in this evaluation. In order to fully determine the MAMMI prototype's performance, we have adapted the measurements suggested for National Electrical Manufacturers Association (NEMA) NU 2-2007 and NU 4-2008 protocol tests, as they are defined for whole-body and small animal PET scanners, respectively. RESULTS: Spatial resolutions of 1.6, 1.8, and 1.9 mm were measured in the axial, radial, and tangential directions, respectively. A scatter fraction of 20.8% was obtained and the maximum NEC was determined to be 25 kcps at 44 MBq. The average sensitivity of the system was observed to be 1% for an energy window of (250 keV-750 keV) and a maximum absolute sensitivity of 1.8% was measured at the FOV center. CONCLUSIONS: The overall performance of the MAMMI reported on this evaluation quantifies its ability to produce high quality PET images. Spatial resolution values below 3 mm were measured in most of the FOV. Only the radial component of spatial resolution exceeds the 3 mm at radial positions larger than 60 mm. This study emphasizes the need for standardized testing methodologies for dedicated breast PET systems similar to NEMA standards for whole-body and small animal PET scanners.