M. Ferreira

Publications (15)5.94 Total impact

• Conference Proceeding: Automatic Configuration of a Medical Imaging System to Unknown Delays in Synchronous Input Data Channels

  C. Leong, J.P. Teixeira, I.C. Teixeira, R. Bugalho, M. Ferreira, P. Rodrigues, J.C. Silva, P. Lousã, J. Varela
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  ABSTRACT: The purpose of this paper is to present a new method and structure for the automatic configuration of a digital system to unknown delays in synchronous input data channels. The method makes possible to restore synchronism in node-to-node communication. Synchronism may be lost due to different delays introduced by the various communication channels. The proposed method allows differences in the channel delays larger than one clock cycle. The method targets distributed digital systems with high number of node-to-node communication channels that must transmit high data volume at high data rates and maintain data time coherence. The method is used in a medical imaging system, namely in the Data Acquisition (DAQ) module of the Data Acquisition Electronics (DAE) component of a PEM (Positron Emission Mammography) system. The system is implemented in a multiple FPGA platform (9 Xilinx™ xc2v4000-4bf957 FPGA). The method and its architectural solution have been validated in a hardware prototype. Test results are presented.
  Circuits and Systems (ISCAS), Proceedings of 2010 IEEE International Symposium on; 07/2010
• Conference Proceeding: Characterization of the Clear-PEM breast imaging scanner performance

  E. Albuquerque, F.G. Almeida, P. Almeida, E. Auffray, J. Barbosa, A.L. Bastos, V. Bexiga, R. Bugalho, C. Cardoso, S. Carmona, [......], A.I. Santos, J. Santos, M.M. Silva, S. Tavernier, I.C. Teixeira, J.P. Teixeira, J.C. Silva, R. Silva, A. Trindade, J. Varela
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  ABSTRACT: We present results on the characterization of the Clear-PEM breast imaging scanner. Clear-PEM is a dual-head Positron Emission Mammography scanner using APD-based detector modules that are capable of measuring depth-of-interaction (DOI) with a resolution of 2 mm in LYSO:Ce crystals. The full system comprises 192 detector modules in a total of 6144 LYSO:Ce crystals and 384 32-pixel APD arrays readout by ASICs with 192 input channels, which represents an unprecedented level of integration in APD-based PET systems. The system includes Frontend and Data Acquisition electronics and a robotic gantry for detector placement and rotation. The software implements calibration (energy, time and DOI), normalization and image reconstruction algorithms. In this work, the scanner main technical characteristics, calibration strategies and the spectrometric performance in a clinical environment are presented. Images obtained with point sources and extended uniform sources are also presented. The first commissioning results show 99.7% active channels. After calibration, the dispersion of the channels absolute gain is 15.3%, which demonstrate that despite the large number of channels the system is rather uniform. The mean energy resolution at 511 keV is 15.9% for all channels, and the mean DOI constant is 5.9%/mm, which is consistent with a 2 mm DOI resolution, or better. The coincidence time resolution at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM. The image resolution measured with point sources was found to be of the order of 1.3 mm FWHM. The DOI capability was found to have a strong impact on the image sharpness. Images of extended uniform ⁶⁸Ge sources, corrected for sensitivity and for the artifacts due detector dead spaces, have good uniformity. First clinical breast images are presented.
  Nuclear Science Symposium Conference Record (NSS/MIC), 2009 IEEE; 12/2009
• Source

  Available from: Catarina Ortigão

  Article: Experimental characterization of the Clear-PEM scanner spectrometric performance

  R Bugalho, B Carriço, C S Ferreira, M Frade, M Ferreira, R Moura, C Ortigão, J F Pinheiro, P Rodrigues, I Rolo, J C Silva, A Trindade, J Varela
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  ABSTRACT: In the framework of the Clear-PEM project for the construction of a high-resolution and high-specificity scanner for breast cancer imaging, a Positron Emission Mammography tomograph has been developed and installed at the Instituto Português de Oncologia do Porto hospital. The Clear-PEM scanner is mainly composed by two planar detector heads attached to a robotic arm, trigger/data acquisition electronics system and computing servers. The detector heads hold crystal matrices built from 2 × 2 × 20 mm3 LYSO:Ce crystals readout by Hamamatsu S8550 APD arrays. The APDs are optically coupled to both ends of the 6144 crystals in order to extract the DOI information for each detected event. Each one of 12288 APD's pixels is read and controlled by Application Specific Integrated Circuits water-cooled by an external cooling unit. The Clear-PEM frontend boards innovative design results in a unprecedented integration of the crystal matrices, APDs and ASICs, making Clear-PEM the PET scanner with the highest number of APD pixels ever integrated so far. In this paper, the scanner's main technical characteristics, calibration strategies and the first spectrometric performance evaluation in a clinical environment are presented. The first commissioning results show 99.7% active channels, which, after calibration, have inter-pixel and absolute gain distributions with dispersions of, respectively, 12.2% and 15.3%, demonstrating that despite the large number of channels, the system is uniform. The mean energy resolution at 511 keV is of 15.9%, with a 8.8% dispersion, and the mean CDOI−1 is 5.9%/mm, with a 7.8% dispersion. The coincidence time resolution, at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM.
  Journal of Instrumentation 10/2009; 4(10):P10011. · 1.87 Impact Factor
• Article: Characterization of avalanche photodiode arrays for the ClearPEM and ClearPEM-Sonic scanners

  R Bugalho, B Carriço, C S Ferreira, M Frade, M Ferreira, R Moura, J Neves, C Ortigão, J F Pinheiro, P Rodrigues, I Rolo, J C Silva, R Silva, A Trindade, J Varela
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  ABSTRACT: The ClearPEM scanner is a high-resolution Positron Emission Mammography prototype, developed by the Portuguese PET Consortium in the framework of the Crystal Clear Collaboration at the European Organization for Nuclear Research (CERN). The scanner is based on a novel readout scheme which uses fine-pitch scintillator crystals, avalanche photodiodes, low-noise high-gain integrated electronics and a fast reconfigurable digital data acquisition system. The scanner uses two planar detector heads each composed of 96 detector modules. The detector module is composed of a matrix of 32 identical 2 × 2 × 20 mm3 LYSO:Ce scintillator crystals, coupled at both ends to Hamamatsu S8550 APD arrays for Depth-of-Interaction (DOI) measurements. More recently, a new scanner named ClearPEM-Sonic which combines the ClearPEM technology with an Ultrasound apparatus, is being produced. A set of 984 APD arrays used in both scanner assemblies followed a quality control protocol and a characterization procedure. This paper describes the methods used in these measurements and the results obtained with the full APD production batch.
  Journal of Instrumentation 09/2009; 4(09):P09009. · 1.87 Impact Factor
• Conference Proceeding: High-speed Data Acquisition Electronics for a PEM scanner

  P. Lousa, F.G. Almeida, P. Almeida, A.L. Bastos, V. Bexiga, R. Bugalho, S. Carmona, B. Carrico, C.S. Ferreira, N.C. Ferreira, [......], J. Sampaio, A.I. Santos, S. Tavernier, I.C. Teixeira, J.P. Teixeira, N. Pimenta, M.C. Martins, J.C. Silva, A. Trindade, J. Varela
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  ABSTRACT: Positron Emission based mammography systems are expected to constitute a significant breakthrough in the early diagnosis of breast cancer. This may lead to a significant enlargement in the horizon of women life, since breast cancer is considered to be among the most deadly types. With this purpose, a consortium has been built to develop a mammography PET system in the framework of the Clear-PEM Collaboration. The Clear-PEM scanner is a unique Positron Emission Mammography (PEM) scanner using APD-based detectors. It is capable of measuring Depth-of-Interaction (DoI) with a resolution of 2 mm in LYSO:Ce crystals, enabling a spatial resolution of 1.2 mm. An important part of the PEM scanner is a high-speed DAE (Data Acquisition Electronics) system. DAE has been developed to process and acquire data coming from the 12,288 front-end (FE) photo-detector channels. In this paper, an overview of this scanner (system and board-level electronics, mechanical design, service and image reconstruction software) is presented, focusing on the specification and implementation of the DAE which is responsible for real-time retrieving, analyzing, filtering and formatting the data coming from the front-end. The objective is to identify relevant data and after conditioning, according to pre-defined protocols, send the data to an acquisition PC for image reconstruction. Communication between DAE and PC is carried out using the S-Link (proprietary of CERN) protocol. Experimental results of validation and test of the DAE system are presented.
  Real Time Conference, 2009. RT '09. 16th IEEE-NPSS; 06/2009
• Conference Proceeding: An overview of the Clear-PEM breast imaging scanner

  E. Albuquerque, F. G. Almeida, P. Almeida, E. Auffray, J. Barbosa, A. L. Bastos, V. Bexiga, R. Bugalho, S. Carmona, B. Carrico, [......], A. I. Santos, J. Santos, M. M. Silva, S. Tavernier, I. C. Teixeira, J. P. Teixeira, R. Silva, J. C. Silva, A. Trindade, J. Varela
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  ABSTRACT: We present an overview of the Clear-PEM breast imaging scanner. Clear-PEM is a unique dual-head Positron Emission Mammography scanner using APD-based detector modules that are capable of measuring depth-of-interaction (DOI) with a resolution of 2 mm in 20 mm long LYSO:Ce crystals. Such capability leads to an image spatial resolution of 1.2 mm and a high efficiency, foreseeing the detection of 3 mm breast lesions in less than 7 minutes exams. The full system comprises 192 detector modules in a total of 6144 LYSO:Ce crystals and 384 32-pixel APD arrays readout by ASICs with 192 input channels that represents an unprecedented level of integration in PET systems. Throughout the project and besides the detector module, we had developed dedicated Frontend and Data Acquisition electronics, the mechanical design and construction of the detector heads and the robotic gantry, as well as all the software that include calibration (energy, time and DOI), normalization and image reconstruction algorithms. In this work we will discuss the developments and present the commissioning results of the detector before the beginning of the clinical trials program, scheduled for the end of the present year.
  Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE; 11/2008
• Article: Clear-PEM: A PET imaging system dedicated to breast cancer diagnostics

  M. C. Abreu, D. Aguiar, E. Albuquerque, F. G. Almeida, P. Almeida, P. Amaral, E. Auffray, P. Bento, P. Bruyndonckx, R. Bugalho, [......], P. Rodrigues, A. I. Santos, J. C. Silva, M. M. Silva, S. Tavernier, I. C. Teixeira, J. P. Teixeira, A. Trindade, J. Trurnmer, J. Varela
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  ABSTRACT: The Clear-PEM scanner for positron emission mammography under development is described. The detector is based on pixelized LYSO crystals optically coupled to avalanche photodiodes and readout by a fast low-noise electronic system. A dedicated digital trigger (TGR) and data acquisition (DAQ) system is used for on-line selection of coincidence events with high efficiency, large bandwidth and small dead-time. A specialized gantry allows to perform exams of the breast and of the axilla. In this paper we present results of the measurement of detector modules that integrate the system under construction as well as the imaging performance estimated from Monte Carlo simulated data. (c) 2006 Elsevier B.V. All rights reserved.
  Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 01/2007; 571(1-2):81-84.
• Source

  Available from: Pedro Lousã

  Article: Design and evaluation of the clear-PEM scanner for positron emission mammography

  M.C. Abreu, J.D. Aguiar, F.G. Almeida, P. Almeida, P. Bento, B. Carrico, M. Ferreira, N.C. Ferreira, F. Goncalves, C. Leong, [......], P. Rodrigues, J. Sampaio, A.I. Santos, L. Silva, J.C. Silva, P. Sousa, I.C. Teixeira, J.P. Teixeira, A. Trindade, J. Varela
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  ABSTRACT: The design and evaluation of the imaging system Clear-PEM for positron emission mammography, under development by the PEM Consortium within the framework of the Crystal Clear Collaboration at CERN, is presented. The proposed apparatus is based on fast, segmented, high atomic number radiation sensors with depth-of-interaction measurement capabilities, and state-of-the-art data acquisition techniques. The camera consists of two compact and planar detector heads with dimensions 16.5×14.5 cm² for breast and axilla imaging. Low-noise integrated electronics provide signal amplification and analog multiplexing based on a new data-driven architecture. The coincidence trigger and data acquisition architecture makes extensive use of pipeline processing structures and multi-event memories for high efficiency up to a data acquisition rate of one million events/s. Experimental validation of the detection techniques, namely the basic properties of the radiation sensors and the ability to measure the depth-of-interaction of the incoming photons, are presented. System performance in terms of detection sensitivity, count-rates and reconstructed image spatial resolution were also evaluated by means of a detailed Monte Carlo simulation and an iterative image reconstruction algorithm.
  IEEE Transactions on Nuclear Science 03/2006; · 1.45 Impact Factor
• Article: Elastic properties of natural rubber tubes produced by dip-coating

  W. F. P. Neves, C. F. D. Graeff, M. Ferreira, M. Mulato, M. S. Bernardes, J. Coutinho-Netto
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  ABSTRACT: Times Cited: 6
  Journal of Applied Polymer Science. 01/2006; 100:702-707.
• Article: Influence of fabrication process on the final properties of natural-rubber latex tubes for vascular prosthesis

  W. F. P. Neves-Junior, M. Ferreira, M. C. O. Alves, C. F. O. Graeff, M. Mulato, J. Coutinho-Netto, M. S. Bernardes
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  ABSTRACT: Times Cited: 9
  Brazilian Journal of Physics 01/2006; 36:586-591. · 0.75 Impact Factor
• Article: Design and evaluation of the Clear-PEM scanner for positron emission mammography

  M. C. Abreu, J. D. Aguiar, F. G. Almeida, P. Almeida, P. Bento, B. Carrico, M. Ferreira, N. C. Ferreira, F. Goncalves, C. Leong, [......], P. Rodrigues, J. Sampaio, A. I. Santos, L. Silva, J. C. Silva, P. Sousa, I. C. Teixeira, J. P. Teixeira, A. Trindade, J. Varela
  [show abstract] [hide abstract]
  ABSTRACT: The design and evaluation of the imaging system Clear-PEM for positron emission mammography, under development by the PEM Consortium within the framework of the Crystal Clear Collaboration at CERN, is presented. The proposed apparatus is based on fast, segmented., high atomic number radiation sensors with depth-of-interaction measurement capabilities, and state-of-the-art data acquisition techniques. The camera consists of two compact and planar detector heads with dimensions 16.5 x 14.5 cm(2) for breast and axilla imaging. Low-noise integrated electronics provide signal amplification and analog multiplexing based on a new data-driven architecture. The coincidence trigger and data acquisition architecture makes extensive use of pipeline processing structures and multi-event memories for high efficiency up to a data acquisition rate of one million events/s. Experimental validation of the detection techniques, namely the basic properties of the radiation sensors and the ability to measure the depth-of-interaction of the incoming photons, are presented. System performance in terms of detection sensitivity, count-rates and reconstructed image spatial resolution were also evaluated by means of a detailed Monte Carlo simulation and an iterative image reconstruction algorithm.
  Ieee Transactions on Nuclear Science. 01/2006; 53(1):71-77.
• Conference Proceeding: First experimental results with the Clear-PEM detector

  M.C. Abreu, J.D. Aguiar, E. Albuquerque, F.G. Almeida, P. Almeida, P. Amaral, P. Bento, R. Bugalho, B. Carrico, H. Cordeiro, [......], J. Rego, R. Ribeiro, P. Rodrigues, A.I. Santos, J.C. Silva, M.M. Silva, I.C. Teixeira, J.P. Teixeira, A. Trindade, J. Varela
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  ABSTRACT: First experimental results of the imaging system Clear-PEM for positron emission mammography, under development within the framework of the Crystal Clear Collaboration at CERN, are presented. The quality control procedures of crystal pixels, APD arrays and assembled detector modules are described. The detector module performance was characterized in detail. Results on measurements of light yield, energy resolution, depth-of-interaction and inter-channel cross-talk are discussed. The status of the development of the front-end electronics and of the data acquisition boards is reported.
  Nuclear Science Symposium Conference Record, 2005 IEEE; 11/2005
• Article: First experimental results with the clear-PEM detector

  M. C. Abreu, J. D. Aguiar, E. Albuquerque, F. G. Almeida, P. Almeida, P. Amaral, P. Bento, R. Bugalho, B. Carrico, H. Cordeiro, [......], J. Rego, R. Ribeiro, P. Rodrigues, A. I. Santos, J. C. Silva, M. M. Silva, I. C. Teixeira, J. P. Teixeira, A. Trindade, J. Varela
  [show abstract] [hide abstract]
  ABSTRACT: First experimental results of the imaging system Clear-PEM for positron emission mammography, under development within the framework of the Crystal Clear Collaboration at CERN, are presented. The quality control procedures of crystal pixels, APD arrays and assembled detector modules are described. The detector module performance was characterized in detail. Results on measurements of light yield, energy resolution, depth-of-interaction and inter-channel cross-talk are discussed. The status of the development of the front-end electronics and of the data acquisition boards is reported.
  2005 IEEE Nuclear Science Symposium Conference Record, Vols 1-5. 01/2005;
• Conference Proceeding: Design and evaluation of the clear-PEM detector for positron emission mammography

  A.I. Santos, P. Almeida, M.V. Martins, N. Matela, N. Oliveira, N.C. Ferreira, J.D. Aguiar, F.G. Almeida, F. Lopes, J. Sampaio, [......], P. Sousa, M. Ferreira, R. Moura, C. Ortigao, L. Peralta, R. Ribeiro, P. Rodrigues, J.C. Silva, A. Trindade, J. Varela
  [show abstract] [hide abstract]
  ABSTRACT: The design and evaluation of the imaging system Clear-PEM for positron emission mammography, under development by the PEM Consortium within the framework of the Crystal Clear Collaboration at CERN, is presented. The proposed apparatus is based on fast, segmented, high atomic number radiation sensors with depth-of-interaction measurement capabilities and state-of-the-art data acquisition techniques. The camera consists of two compact and planar detector heads with adequate field-of-view dimensions for breast and axilla imaging. Low-noise integrated electronics provide signal amplification and analog multiplexing based on a new data-driven architecture. The coincidence trigger and data acquisition architecture makes extensive use of pipeline processing structures and multi-event memories for high efficiency up to a data acquisition rate of one million events/s. Experimental validation of the detection techniques, namely the basic properties of the radiation sensors and the ability to measure the depth-of-interaction of the incoming photons, are presented. System performance in terms of detection sensitivity, count-rates and reconstructed image spatial resolution were also evaluated by means of a detailed Monte Carlo simulation and an iterative image reconstruction algorithm.
  Nuclear Science Symposium Conference Record, 2004 IEEE; 11/2004
• Source

  Available from: Peter Bruyndonckx

  Article: Clear-PEM: A PET imaging system dedicated to breast cancer diagnostics

  M.C. Abreu, D. Aguiar, E. Albuquerque, F.G. Almeida, P. Almeida, P. Amaral, E. Auffray, P. Bento, P. Bruyndonckx, R. Bugalho, [......], P. Rodrigues, A.I. Santos, J.C. Silva, M.M. Silva, S. Tavernier, I.C. Teixeira, J.P. Teixeira, A. Trindade, J. Trummer, J. Varela
  [show abstract] [hide abstract]
  ABSTRACT: The Clear-PEM scanner for positron emission mammography under development is described. The detector is based on pixelized LYSO crystals optically coupled to avalanche photodiodes and readout by a fast low-noise electronic system. A dedicated digital trigger (TGR) and data acquisition (DAQ) system is used for on-line selection of coincidence events with high efficiency, large bandwidth and small dead-time. A specialized gantry allows to perform exams of the breast and of the axilla. In this paper we present results of the measurement of detector modules that integrate the system under construction as well as the imaging performance estimated from Monte Carlo simulated data.
  Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.