We present performance results for a PET detector prototype in simultaneous operation within a 7 T MR system. The detectors are based on ClearPEM technology, a dedicated PET scanner for high-resolution breast imaging, and suitable for... more
We present performance results for a PET detector prototype in simultaneous operation within a 7 T MR system. The detectors are based on ClearPEM technology, a dedicated PET scanner for high-resolution breast imaging, and suitable for integration into combined PET/MR systems at ultra-high magnetic fields. To demonstrate simultaneous PET/MR detection with minimal electromagnetic interference between the two systems, the PET detectors and front-end electronics were carefully shielded and a new dedicated RF volume coil was constructed to mitigate electromagnetic coupling with the shielded electronics. Noise measurements at the level of the PET front-end electronics and the MR RF receiver have shown the mutual interference of RF power and digital noise, and demonstrated the excellent shielding effectiveness achieved. Simultaneous data acquisitions with a Ge-68 source and a saline phantom have shown no distortions or artifacts on MR images caused by the detector modules, and no degradati...
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The Clear-PEM prototype under development aims to improve early stage breast cancer diagnostics. The proposed device is based on cerium doped lutetium crystal matrices developed by the Crystal Clear Collaboration, as well as on modern... more
The Clear-PEM prototype under development aims to improve early stage breast cancer diagnostics. The proposed device is based on cerium doped lutetium crystal matrices developed by the Crystal Clear Collaboration, as well as on modern data acquisition techniques. A series of Monte Carlo studies were performed to evaluate detection sensitivity, background rate and intrinsic spatial resolution in order to optimize
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The ClearPEM scanner is a dedicated system to perform breast imaging with the ability of measuring DOI, allowing an image spatial resolution close to 1.5 mm. The DOI is measured by calculating the amplitude asymmetry between the signals... more
The ClearPEM scanner is a dedicated system to perform breast imaging with the ability of measuring DOI, allowing an image spatial resolution close to 1.5 mm. The DOI is measured by calculating the amplitude asymmetry between the signals produced by two APD, one in the top and other in the bottom of the crystal. The DOI resolution measured in laboratory
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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... more
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
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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... more
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
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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)... more
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
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The ClearPEM detector is a dual planar Positron Emission Mammography (PEM) scanner that was developed within the framework of the international Crystal Clear Collaboration at CERN. The scanner is being used for preclinical studies and the... more
The ClearPEM detector is a dual planar Positron Emission Mammography (PEM) scanner that was developed within the framework of the international Crystal Clear Collaboration at CERN. The scanner is being used for preclinical studies and the new phase of the clinical trials will start on the second half of November. A second prototype was build and installed (ClearPEM-Sonic). The main
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ABSTRACT
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ABSTRACT ClearPEM is a rotating, dual planar detector PET system dedicated to breast and axilla imaging that needs data corrections in order to improve quantification and lesion detectability. Since the scanner does not have CT nor... more
ABSTRACT ClearPEM is a rotating, dual planar detector PET system dedicated to breast and axilla imaging that needs data corrections in order to improve quantification and lesion detectability. Since the scanner does not have CT nor transmission sources, we are implementing data corrections that use emission-only data. Also, since in this work we are using an iterative list-mode reconstruction algorithm that projects the data directly through a 3D grid of points, all the corrections are applied in image space. We describe the current implementation and validation of image-based corrections for normalization, scatter, attenuation and randoms. Normalization correction uses sensitivity images generated by backprojecting data from a planar source. Energy-based scatter correction is applied using the Estimation of Trues Method because this method does not require information about attenuating media and takes into account the activity outside the FOV. Attenuation correction is calculated from the segmentation of the breast in the emission images. Randoms correction is performed by subtraction of a smoothed image obtained from the backprojection of the delayed coincidences. The implementation of other corrections is also being pursued in order to obtain fully quantitative images in breast imaging.
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Research Interests: Algorithms, Biomedical Engineering, Monte Carlo Simulation, Monte Carlo, Nuclear medicine, and 15 moreQuality Control, Humans, Computer Simulation, Maximum Likelihood, Breast, High Resolution, Shift Invariant, Image Enhancement, Single Photon Emission Computed Tomography, Discrete random variable, Estimation Method, Likelihood Functions, Monte Carlo Method, Elementary Particles, and Scatter correction
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During the last decade there was a growing interest on the application of Positron Emission Tomography, PET, techniques to Breast Imaging. More recently, preliminary results suggested the use of dedicated devices to Breast Imaging using... more
During the last decade there was a growing interest on the application of Positron Emission Tomography, PET, techniques to Breast Imaging. More recently, preliminary results suggested the use of dedicated devices to Breast Imaging using the same technique, the so-called Positron Emission Mammography cameras, PEM. In this article we review the arguments leading to a dedicated instrument. Based on these
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Research Interests: Biomedical Engineering, Monte Carlo Simulation, Positron Emission Tomography, Biomedical Imaging, Image Reconstruction, and 11 moreData acquisition, Nuclear science, Low Noise, Spatial resolution, Experimental Validation, System performance, Gamma Ray, High Efficiency, Simulation Software, Depth of interaction, and imaging system
... provides the basic services and infrastructure required for the development of flexible simulation frameworks and applications, which ave found generalized use in high energy physics, nuclear physics, astrophysics, and medical ... R.... more
... provides the basic services and infrastructure required for the development of flexible simulation frameworks and applications, which ave found generalized use in high energy physics, nuclear physics, astrophysics, and medical ... R. Moura, C. Ortigão, and J. Varela are with the ...