Time of flight measurements based on FPGA using a breast dedicated PET

In this work the implementation of a Time-to-Digital Converter (TDC) using a Nutt delay line FPGA-based and applied on a Positron Emission Tomography (PET) device is going to be presented in order to check the system’s suitability for Time of Flight (TOF) measurements. In recent years, FPGAs have shown great advantages for precise time measurements in PET. The architecture employed for these measurements is described in detail. The system developed was tested on a dedicated breast PET prototype, composed of LYSO crystals and Positive Sensitive Photomultipliers (PSPMTs). Two distinct experiments were carried out for this purpose. In the first test, system linearity was evaluated in order to calibrate the time measurements, providing a linearity error of less than 2% and an average time resolution of 1.4 ns FWHM. The second set of measurements tested system resolution, resulting in a FWHM as good as 1.35 ns. The results suggest that the coincidence window for the current PET can be reduced in order to minimize the random events and thus, achieve better image qualityAguilar, A.; García Olcina, R.; Martos, J.; Soret, J.; Torres-Pais, J.; Benlloch Baviera, JM.; González Martínez, AJ.... (2014). Time of flight measurements based on FPGA using a breast dedicated PET. Journal of Instrumentation. 9:0-8. doi:10.1088/1748-0221/9/05/C05012S08

Colegio internado de lzarra Vitoria – España

This new pavilion completes the female boarding school and an attempt has been made to integrate the entire unit into the surrounding landscape. For greater economy and shorter construction time, systems have been selected for the greatest possible use of prefabricated elements as well as modular building units. Different prefabrication systems have been used for the common zones, auditoriums, bedrooms and dining room and the building has been covered with prefabricated timber trusses, compressed wood pulp boards and cement tiles. The College is equipped with heating, fire extinction appliances and ventilation in the bedrooms. Within the framework of modern technology the results fulfill the aims set up by the proprietors.Con este nuevo pabellón exento se completa el internado masculino existente, cuidando de integrar el conjunto edificado en el paisaje circundante. En beneficio de las máximas economía y rapidez de construcción, se han elegido sistemas que permitan la mayor utilización de elementos prefabricados, procurando acudir a una modulación rígida donde ha sido posible. Se emplean diferentes sistemas de prefabricación para las zonas comunes, aulas y comedor y dormitorios, cubriendo el edificio con cerchas prefabricadas de madera, tableros aglomerados y tejas de cemento. El Colegio está dotado de calefacción, protección contra incendios y ventilación forzada en dormitorios y aseos. El resultado satisface las aspiraciones expuestas por la propiedad, dentro de la tecnología moderna

A Fast 0.5 T Prepolarizer Module for Preclinical Magnetic Resonance Imaging

We present a magnet and high power electronics for Prepolarized Magnetic Resonance Imaging (PMRI) in a home-made, special-purpose preclinical system designed for simultaneous visualization of hard and soft biological tissues. The sensitivity of MRI systems grows with field strength, but so do their costs. PMRI can boost the signal-to-noise ratio (SNR) in affordable low-field scanners by means of a long and strong magnetic pulse. However, this must be rapidly switched off prior to the imaging pulse sequence, in timescales shorter than the spin relaxation (or T1) time of the sample. We have operated our prepolarizer at up to 0.5 T and demonstrated enhanced magnetization, image SNR and tissue contrast with PMRI of tap water, an ex vivo mouse brain and food samples. These have T1 times ranging from hundreds of milli-seconds to single seconds, while the preliminary high-power electronics setup employed in this work can switch off the prepolarization field in tens of milli-seconds. In order to make this system suitable for solid-state matter and hard tissues, which feature T1 times as short as 10 ms, we are developing new electronics which can cut switching times to ~ 300 μs. This does not require changes in the prepolarizer module, opening the door to the first experimental demonstration of PMRI on hard biological tissues

Programmable integrated front-end for SiPM/PMT PET detectors with continuous scintillating crystal

[EN] AMIC architecture has been introduced in previous works in order to provide a generic and expandable solution for implementing large number of outputs SiPM array/PMT detectors. The underlying idea in AMIC architecture is to calculate the moments of the detected light distribution in an analog fashion. These moments provide information about energy, x/y position, etc. of the light distribution of the detected event. Moreover this means that a small set of signals contains most of the information of the event, thus reducing the number of channels to be acquired. This paper introduces a new front-end device AMIC2GR which implements the AMIC architecture improving the features of the former integrated devices. Higher bandwidth and filtering coefficient precision along with a lower noise allow to apply some detector enhancements. Inhomogeneity among detector elements throughout the array can be reduced. Depth of interaction measurements can be obtained from the light distribution analysis. Also a common trigger signal can be obtained for the whole detector array. Finally AMIC2GR preamplifier stage close to SiPM output signals optimizes signal to noise ratio, which allows to reduce SiPM gain by using lower operating voltages thus reducing dark noiseThis work was supported by Universitat Politecnica de Val ` encia ` through research program PAID06-10-2212.Herrero Bosch, V.; Monzó Ferrer, JM.; Ros García, A.; Aliaga Varea, RJ.; González Martínez, AJ.; Montoliu, C.; Colom Palero, RJ.... (2012). Programmable integrated front-end for SiPM/PMT PET detectors with continuous scintillating crystal. Journal of Instrumentation. 7. https://doi.org/10.1088/1748-0221/7/12/C12021S7Llosa, G., Barrio, J., Cabello, J., Lacasta, C., Oliver, J. F., Rafecas, M., … Piemonte, C. (2011). Development of a PET prototype with continuous LYSO crystals and monolithic SiPM matrices. 2011 IEEE Nuclear Science Symposium Conference Record. doi:10.1109/nssmic.2011.6153684Herrero-Bosch, V., Lerche, C. W., Spaggiari, M., Aliaga-Varea, R., Ferrando-Jodar, N., & Colom-Palero, R. (2011). AMIC: An Expandable Front-End for Gamma-Ray Detectors With Light Distribution Analysis Capabilities. IEEE Transactions on Nuclear Science, 58(4), 1641-1646. doi:10.1109/tns.2011.2152855Lerche, C. W., Benlloch, J. M., Sanchez, F., Pavon, N., Escat, B., Gimenez, E. N., … Martinez, J. (2005). Depth of /spl gamma/-ray interaction within continuous crystals from the width of its scintillation light-distribution. IEEE Transactions on Nuclear Science, 52(3), 560-572. doi:10.1109/tns.2005.851424Lerche, C. W., Herrero-Bosch, V., Spaggiari, M., Mateo-Jimenez, F., Monz-Ferrer, J. M., Colom-Palero, R. J., & Mora-Mas, F. (2010). Fast circuit topology for spatial signal distribution analysis. 2010 17th IEEE-NPSS Real Time Conference. doi:10.1109/rtc.2010.5750391Bult, K., & Geelen, G. J. G. M. (1992). An inherently linear and compact MOST-only current division technique. IEEE Journal of Solid-State Circuits, 27(12), 1730-1735. doi:10.1109/4.17309

Portable magnetic resonance imaging of patients indoors, outdoors and at home

Mobile medical imaging devices are invaluable for clinical diagnostic purposes both in and outside healthcare institutions. Among the various imaging modalities, only a few are readily portable. Magnetic resonance imaging (MRI), the gold standard for numerous healthcare conditions, does not traditionally belong to this group. Recently, low-field MRI start-up companies have demonstrated the first decisive steps towards portability within medical facilities, but these are so far incompatible with more demanding use cases such as in remote and developing regions, sports facilities and events, medical and military camps, or home healthcare. Here we present in vivo images taken with a light, home-made, low-field extremity MRI scanner outside the controlled environment provided by medical facilities. To demonstrate the true portability of the system and benchmark its performance in various relevant scenarios, we have acquired images of a volunteer's knee in: i) an MRI physics laboratory; ii) an office room; iii) outside a campus building, connected to a nearby power outlet; iv) in open air, powered from a small fuel-based generator; and v) at the volunteer's home. All images have been acquired within clinically viable times, and signal-to-noise ratios (SNR) and tissue contrast suffice for 2D and 3D reconstructions with diagnostic value, with comparable overall image quality across all five situations. Furthermore, the volunteer carries a fixation metallic implant screwed to the femur, which leads to strong artifacts in standard clinical systems but appears sharp in our low-field acquisitions. Altogether, this work opens a path towards highly accessible MRI under circumstances previously unrealistic.Comment: 17 pages, 4 figures, comments welcom

Calibration and performance tests of detectors for laser-accelerated protons

We present the calibration and performance tests carried out with two detectors for intense proton pulses accelerated by lasers. Most of the procedures were realized with proton beams of 0.46-5.60 MeV from a tandem accelerator. One approach made use of radiochromic films, for which we calibrated the relation between optical density and energy deposition over more than three orders of magnitude. The validity of these results and of our analysis algorithms has been confirmed by controlled irradiation of film stacks and reconstruction of the total beam charge for strongly non-uniform beam profiles. For the spectral analysis of protons from repeated laser shots, we have designed an online monitor based on a plastic scintillator. The resulting signal from a photomultiplier directly measured on a fast oscilloscope is especially useful for time-of-flight applications. Variable optical filters allow for suppression of saturation and an extension of the dynamic range. With pulsed proton beams we have tested the detector response to a wide range of beam intensities from single particles to 3 ×105 protons per 100 ns time interval.Project funded by the Spanish Ministry of Economy and Competitiveness and co-funded with FEDER's funds within the INNPACTO 2011 program under Grant No. IPT-2011-0862-900000. This work was supported by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I+D+i) under Grant No. TEC 2013-48036-C3-1-R and the Valencian Local Government under Grants PROMETEOII/2013/010 and ISIC 2011/013. The work of A. J. Gonzalez is financed by CSIC with a JAE-Doc contract under Junta de Ampliacion de Estudios program, cofinanced by the European Social Fund.Peer Reviewe