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Sanchez F.,Polytechnic University of Valencia | Orero A.,Polytechnic University of Valencia | Soriano A.,Polytechnic University of Valencia | Correcher C.,Oncovision | And 9 more authors.
Medical Physics | Year: 2013

Purpose: The authors have developed a trimodal PETSPECTCT 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 99mTc 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 cpsMBq (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 PETSPECTCT 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. © 2013 American Association of Physicists in Medicine.


Moliner L.,Polytechnic University of Valencia | Alamo J.,Oncovision | Hellingman D.,Oncovision | Peris J.L.,Polytechnic University of Valencia | And 6 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2016

In this work we present the MAMMOCARE prototype, a biopsy guided system based on PET. The system is composed by an examination table where the patient is situated in prone position, a PET detector and a biopsy device. The PET detector is composed by two rings. These rings can be separated mechanically in order to allow the needle insertion. The first acquisition is performed with the closed ring configuration in order to obtain a high quality image to locate the lesion. Then, the software calculates the optimum path for the biopsy and moves the biopsy and PET systems to the desired position. At this point, two compression pallets are used to hold the breast. Then, the PET system opens and the biopsy procedure starts. The images are obtained at several steps to ensure the correct location of the needle during the procedure. The performance of the system is evaluated measuring the spatial resolution and sensitivity according the NEMA standard. The uniformity of the reconstructed images is also estimated. The radial resolution is 1.62mm in the center of the FOV and 3.45mm at 50mm off the center in the radial direction using the closed configuration. In the open configuration the resolution reaches 1.85mm at center and 3.65mm at 50mm. The sensitivity using an energy window of 250keV-750keV is 3.6% for the closed configuration and 2.5% for the open configuration. The uniformity measured in the center of the FOV is 14% and 18% for the closed and open configurations respectively. © 2016 SPIE.


Sanchez F.,CIEMAT | Moliner L.,CIEMAT | Moliner L.,University of Valencia | Correcher C.,Oncovision | And 8 more authors.
Medical Physics | Year: 2012

Purpose: The authors have developed a small animal Positron emission tomography (PET) scanner based on monolithic LYSO crystals coupled to multi-anode photomultiplier tubes (MA-PMTs). In this study, the authors report on the design, calibration procedure, and performance evaluation of a PET system that the authors have developed using this innovative nonpixelated detector design. Methods: The scanner is made up of eight compact modules forming an octagon with an axial field of view (FOV) of 40 mm and a transaxial FOV of 80 mm diameter. In order to fully determine its performance, a recently issued National Electrical Manufacturers Association (NEMA) NU-4 protocol, specifically developed for small animal PET scanners, has been followed. By measuring the width of light distribution collected in the MA-PMT the authors are able to determine depth of interaction (DOI), thus making the proper identification of lines of response (LORs) with large incidence angles possible. PET performances are compared with those obtained with currently commercially available small animal PET scanners. Results: At axial center when the point-like source is located at 5 mm from the radial center, the spatial resolution measured was 1.65, 1.80, and 1.86 mm full width at half maximum (FWHM) for radial, tangential, and axial image profiles, respectively. A system scatter fraction of 7.5 (mouse-like phantom) and 13 (rat-like phantom) was obtained, while the maximum noise equivalent count rate (NECR) was 16.9 kcps at 12.7 MBq (0.37 MBq/ml) for mouse-like phantom and 12.8 kcps at 12.4 MBq (0.042 MBq/ml) for rat-like phantom The peak absolute sensitivity in the center of the FOV is 2 for a 30 peak energy window. Several animal images are also presented. Conclusions: The overall performance of our small animal PET is comparable to that obtained with much more complex crystal pixelated PET systems. Moreover, the new proposed PET produces high-quality images suitable for studies with small animals. © 2012 American Association of Physicists in Medicine.


Moliner L.,Polytechnic University of Valencia | Gonzalez A.J.,Polytechnic University of Valencia | Correcher C.,Oncovision | Benlloch J.M.,Polytechnic University of Valencia
Journal of Instrumentation | Year: 2016

In this work, we present the online implementation of attenuation, scatter and random corrections using the LMEM algorithm for the dedicated breast PET named MAMMI. The attenuation correction is based on image segmentation, the random correction is derived from the rate estimation of single photon events and the scatter correction is determined by the dual energy window method. These three corrections are estimated and implemented in the reconstruction process without almost increasing the reconstruction time. The image quality is evaluated in terms of image uniformity and contrast using the reconstructed images of two custom-designed phantoms. When we apply the three corrections, the measured uniformity in the whole field of view is (10±1)% compared to (17±1)% without corrections. The adapted recovery contrast coefficients (normalized to 1) are approximately (0.80±0.02) in hot areas, improving the value of (0.66±0.07) obtained without corrections. The reconstruction processing time is also studied, finding an increment of around 7% when the three corrections are simultaneously included. Finally, 25 breast image datasets are also analyzed. The average acquisition time per patient is around 1200 seconds and the reconstruction times with corrections vary from 100 to 400 seconds using (1×1×1) mm3 voxel size and from 300 to 1800 seconds using (0.5×0.5×0.5) mm3 voxel size. These reconstructions are performed with a virtual pixel size of (1.6×1.6) mm2 and twelve iterations. © 2016 IOP Publishing Ltd and Sissa Medialab srl.


Barbera J.,Oncovision | Gonzalez A.J.,CIEMAT | Carrilero V.,Oncovision | Correcher C.,Oncovision | And 4 more authors.
2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014 | Year: 2014

SiPMs-based gamma ray detectors have shown a significant development impulse in recent years due to a number of advantages, namely: good time response, small size, magnetic field immunity and low cost. We have designed a special SiPM array formed by 12×12 SiPMs of 3×3 mm2 active area (FB-30035, SensL) that covers a total photosensor area of 5×5 cm2 for gamma ray detection in PET scanners. When thick crystals are considered, pile-up events increase with the scintillation material volume leading to a loss of events and spatial distortions in the image. © 2014 IEEE.


Moliner L.,IFIC Institute Fsica Corpuscular | Benlloch J.M.,IFIC Institute Fsica Corpuscular | Carles M.,IFIC Institute Fsica Corpuscular | Correcher C.,Oncovision | And 4 more authors.
IEEE Nuclear Science Symposium Conference Record | Year: 2010

The system MAMMI (acronym for MAMmography with Molecular Imaging) is a PET prototype device specifically designed for the detection of breast cancer. It is based on continuous LYSO crystals coupled to Position Sensitive Photomultiplier Tubes (PSPMTs). The scanner consists of twelve compact modules assembled on a ring configuration with an aperture of 186 mm. The scanner transaxial Field of View (FoV) is as large as 170 mm in diameter whereas the axial FoV can cover up to 170 mm recording several frames which are software overlapped. Most of the performance characteristic tests according to the National Electrical Manofacturers Association (NEMA) NU 2-2007 are specially designed to whole body PET scanners and, thus, present a dimensional limitation on a dedicated breast PET. Also, NEMA NU 4-2008 standards cannot be either conducted because are performed for small animal PETs. In this paper, we propose certain changes based on both standards, as are the dimensions of the phantoms and sources. The results showed a spatial resolution at the centre of the transaxial and axial FoVs of 1.90 1.82 and 1.63 mm in the radial, tangential and axial profiles, respectively. The system sensitivity was measured to be, on average and using different line sources and metallic sleeves, 0.77%. When using a 22Na point source, a value of up to 1% was observed. For a specific breast phantom, the scatter fraction was determined to be 6.7% and the peak noise equivalent count rate, 25 kcps at 176 MBq/ml. Note that these measures were carried out wiyh a 50% peak energy window and and a coincidence timing window of 5 ns. © 2010 IEEE.


An apparatus to detect gamma rays, comprising a scintillator, a position sensitive photo sensor and a scintillation-light-incidence-angle-constraining, SLIAC, element, the scintillator has faces and the position sensitive photo sensor detects scintillation photons exiting a scintillation photons transparent face of the scintillator, and a portion of a scintillator face is covered with an absorbing layer, which absorbs scintillation photons created by scintillation events due to the interaction of incoming gamma rays with the scintillator, and the SLIAC element is optically coupled between a scintillation photons transparent face of the scintillator and the position sensitive photo sensor and the SLIAC element guides the scintillation photons exiting the scintillator towards the position sensitive photo sensor, and the SLIAC element restricts the maximum allowed half light acceptance angle for the scintillation light hitting the position sensitive photo sensor to less than 45.


Patent
Oncovision and West Virginia University | Date: 2016-05-11

This disclosure describes an imaging radiation detection module with novel configuration of the scintillator sensor allowing for simultaneous optimization of the two key parameters: detection efficiency and spatial resolution, that typically cannot be achieved. The disclosed device is also improving response uniformity across the whole detector module, and especially in the edge regions. This is achieved by constructing the scintillation modules as hybrid structures with continuous (also referred to as monolithic) scintillator plate(s) and pixellated scintillator array(s) that are optically coupled to each other and to the photodetector. There are two basic embodiments of the novel hybrid structure: (1) the monolithic scintillator plate is at the entrance for the incoming radiation, preferably gamma rays, and the pixellated array placed behind the plate, all in optical contact with the photodetector, (2) the order of the scintillator components is reversed with the pixellated scintillation plate placed in front of the monolithic plate.


The invention refers to an apparatus to detect gamma rays, comprising:a scintillator, a position sensitive photo sensor and at least one scintillation-light-incidence-angle-constraining, SLIAC, element, whereinthe scintillator has a plurality of faces; and wherein the position sensitive photo sensor is arranged to detect scintillation photons exiting a scintillation photons transparent face of the scintillator, and wherein at least a portion or the whole of at least one scintillator face is covered with an absorbing layer, which is arranged to absorb scintillation photons created by scintillation events due to the interaction of incoming gamma rays with the scintillator, and wherein the scintillation-light-incidence-angle-constraining, SLIAC, element is optically coupled between a scintillation photons transparent face of the scintillator and the position sensitive photo sensor and the scintillation-light-incidence-angle-constraining, SLIAC,element is configured to guide the scintillation photons exiting the scintillator towards the position sensitive photo sensor, and wherein the scintillation-light-incidence-angle-constraining, SLIAC, element restricts the maximum allowed half light acceptance angle for the scintillation light hitting the position sensitive photo sensor to less than 45.


News Article | November 22, 2016
Site: www.prnewswire.com

BILLERICA, Mass., Nov. 22, 2016 /PRNewswire/ -- Bruker today announced that it has completed the acquisition of the preclinical PET imaging business of Oncovision, a leading provider of innovative medical imaging devices. Bruker had previously announced an agreement to acquire this...

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