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Publications (10 of 15) Show all publications
Turco, A., Valastyán, I. & Colarieti-Tosti, M. (2012). Modular miniPET: A comparison between 10 and 12 detector modules. In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC): . Paper presented at 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012 (pp. 2598-2602). IEEE
Open this publication in new window or tab >>Modular miniPET: A comparison between 10 and 12 detector modules
2012 (English)In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), IEEE , 2012, p. 2598-2602Conference paper, Published paper (Refereed)
Abstract [en]

By means of computer simulations, scatter fraction, spatial resolution and sensitivity of two 10-detector-module small-animal PET (r77-miniPET and r106-miniPET), are analyzed and compared to the performance of the 12-detector-module PET scanner miniPET II [1]. All simulations have been performed with the well validated Geant4 Application for Emission Tomography (GATE) [2]. Sensitivity and scatter fraction speak in favor of the 10-module scanner: a clear improvement in count rate and scatter fraction was found. Moreover, steeper slopes of noise equivalent count rate curves at low levels of activity was found. Spatial resolution instead was found to be better in the 12-module scanner.

Place, publisher, year, edition, pages
IEEE, 2012
Series
IEEE Nuclear Science Symposium Conference Record, ISSN 1095-7863
Keywords
Detector module, Emission tomography, Noise equivalent count rates, PET scanner, Scatter fractions, Small animal PET, Spatial resolution, Steeper slopes
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-129790 (URN)10.1109/NSSMIC.2012.6551594 (DOI)000326814202154 ()2-s2.0-84881601821 (Scopus ID)978-146732030-6 (ISBN)
Conference
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012
Note

QC 20131008

Available from: 2013-10-08 Created: 2013-10-04 Last updated: 2013-12-18Bibliographically approved
Valastyán, I., Colarieti-Tostia, M., Rena, W., Turcoa, A. & Kereka, A. (2012). Monte Carlo simulation of a dental Positron Emission Tomograph and image reconstruction of scatter and true coincidence events. In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC): . Paper presented at 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012 (pp. 3484-3487). IEEE
Open this publication in new window or tab >>Monte Carlo simulation of a dental Positron Emission Tomograph and image reconstruction of scatter and true coincidence events
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2012 (English)In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), IEEE , 2012, p. 3484-3487Conference paper, Published paper (Refereed)
Abstract [en]

Detection of inflammation with nuclear medical imaging techniques [1], especially using PET, has an important role because the location of the disease helps the doctor in the choice of the treatment. In dental applications, the proper treatment of the inflammation might save a tooth.

Place, publisher, year, edition, pages
IEEE, 2012
Series
IEEE Nuclear Science Symposium Conference Record, ISSN 1095-7863
Keywords
Dental applications, Nuclear medical imaging, Positron emission tomograph, Image reconstruction, Monte Carlo methods, Nuclear physics, Pathology, Tomography, Medical imaging
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-129807 (URN)10.1109/NSSMIC.2012.6551795 (DOI)000326814203132 ()2-s2.0-84881567453 (Scopus ID)9781467320306 (ISBN)
Conference
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012
Note

QC 20131008

Available from: 2013-10-08 Created: 2013-10-04 Last updated: 2018-12-03Bibliographically approved
Valastyán, I., Gal, J., Hegyesi, G., Kalinka, G., Nagy, F., Kiraly, B., . . . Balkay, L. (2012). Novel time over threshold based readout method for MRI compatible small animal PET detector. In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC): . Paper presented at 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012 (pp. 1295-1299). IEEE
Open this publication in new window or tab >>Novel time over threshold based readout method for MRI compatible small animal PET detector
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2012 (English)In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), IEEE , 2012, p. 1295-1299Conference paper, Published paper (Refereed)
Abstract [en]

Combined PET-MRI scanners start a new era in medical imaging. However the development of MRI compatible PET detector module is a challenging task. SiPM sensors are insensitive to magnetic field and constitute a promising solution. A drawback is the high dark current. A readout concept for SiPM based small animal PET detector module is presented in this paper. The results show that the readout of the SiPM is possible using only four ADC channels and the position map is comparable to the ideal solution. The detector modules based on the method are feasible solution for MRI compatible PET scanners.

Place, publisher, year, edition, pages
IEEE, 2012
Series
IEEE Nuclear Science Symposium Conference Record, ISSN 1095-7863
Keywords
Detector module, Feasible solution, Ideal solutions, MRI compatible, PET detectors, PET scanner, Small animal PET, Time over thresholds, Medical imaging, Nuclear physics, Scanning, Positron emission tomography
National Category
Medical Engineering
Identifiers
urn:nbn:se:kth:diva-128990 (URN)10.1109/NSSMIC.2012.6551317 (DOI)000326814201088 ()2-s2.0-84881591046 (Scopus ID)9781467320306 (ISBN)
Conference
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012
Note

QC 20130919

Available from: 2013-09-19 Created: 2013-09-17 Last updated: 2020-03-03Bibliographically approved
Ren, W., Valastyán, I. & Colarieti-Tosti, M. (2012). Stationary SPECT with multi-layer multiple-pinhole-arrays. In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC): . Paper presented at 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012 (pp. 2594-2597). IEEE
Open this publication in new window or tab >>Stationary SPECT with multi-layer multiple-pinhole-arrays
2012 (English)In: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), IEEE , 2012, p. 2594-2597Conference paper, Published paper (Refereed)
Abstract [en]

The potential of Multiple Pinhole Arrays (MPA) collimators for developing a Single Photon Emission Computer Tomography (SPECT) system without rotating or moving elements is investigated. A four layer arrangement is proposed and the system performance is evaluated using the simulation toolkit GATE [1]. For a camera with a field of view (FOV) of the order of a human brain (a sphere of radius 100 mm), a sensitivity of 86, 0 cps/MBq and an overall resolution of 5 mm have been estimated, indicating that performances comparable to traditional parallel-hole-collimator cameras can be achieved.

Place, publisher, year, edition, pages
IEEE, 2012
Series
IEEE Nuclear Science Symposium Conference Record, ISSN 1095-7863
Keywords
Field of views, Human brain, Layer arrangement, Multiple pinholes, Simulation toolkits, Single photon emission computer tomographies, Stationary spect, Cameras, Medical imaging, Nuclear physics, Single photon emission computed tomography
National Category
Other Medical Sciences not elsewhere specified
Identifiers
urn:nbn:se:kth:diva-128994 (URN)10.1109/NSSMIC.2012.6551593 (DOI)000326814202153 ()2-s2.0-84881570776 (Scopus ID)978-146732030-6 (ISBN)
Conference
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012; Anaheim, CA; United States; 29 October 2012 through 3 November 2012
Note

QC 20130919

Available from: 2013-09-19 Created: 2013-09-17 Last updated: 2013-12-18Bibliographically approved
Valastyán, I., Kerek, A., Imrek, J., Hegyesi, G., Kalinka, G., Molnar, J. & Novak, D. (2011). LSO based dual slice helical CT and PET demonstrators. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 633, S300-S302
Open this publication in new window or tab >>LSO based dual slice helical CT and PET demonstrators
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2011 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 633, p. S300-S302Article in journal (Refereed) Published
Abstract [en]

Two demonstrators, a spiralCT and a miniPET, have been designed and constructed for educational purposes. Computed tomographs (CTs) and positron emission tomographs (PETs) are some of the most commonly used structural and functional imaging devices in medicine, respectively. There is a need for transparent demonstrators where the principles of the different modalities and their functions are presented. The aim of the developments of these systems was to present the major building blocks of CT and PET for undergraduate students. Photon detection in both systems is based on small pixelised scintillation crystals with position sensitive PMT readout. Similar analogue and digital data processing based on FPGA technique is applied for the demonstrators and common image reconstruction and presentation software components are used.

Keywords
PET, CT, nuclear imaging, Education
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-12068 (URN)10.1016/j.nima.2010.06.195 (DOI)000292782400089 ()2-s2.0-79959859585 (Scopus ID)
Note
QC 20100721. Updated from accepted to published. 11th International Workshop on Radiation Imaging Detectors.Available from: 2010-03-01 Created: 2010-03-01 Last updated: 2017-12-12Bibliographically approved
Valastyán, I. (2010). Software Solutions for Nuclear Imaging Systems in Cardiology, Small Animal Research and Education. (Doctoral dissertation). Stockholm: KTH
Open this publication in new window or tab >>Software Solutions for Nuclear Imaging Systems in Cardiology, Small Animal Research and Education
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The sensitivity for observing physiological processes makes nuclear imaging an important tool in medical diagnostics. Different types of nuclear imaging modalities, with emphasis on the software components and image reconstructions, are presented in this thesis:  the Cardiotom for myocardial heart studies at the Karolinska University Hospital, the small animal Positron Emission Tomograph (PET) scanners for research and the SPECT, PET, spiral CT and Cardiotom demonstrators for the Royal Institute of Technology medical imaging laboratory.

A modular and unified software platform has been developed for data representation, acquisition, visualization, reconstruction and presentation of the programs of the imaging devices mentioned above. The high performance 3D ML-EM and OS-EM iterative image reconstruction methods are implemented both on Cardiotom and miniPET scanners.

As a result, the in-slice resolution of the first two prototypes of the Cardiotom today is the same as the formerly used filtered back-projection, however the in-depth resolution is considerably increased. Another improvement due to the new software is the shorter time that is required for data acquisition and image reconstruction. The new electronics with the newly developed software ensure images for medical diagnosis within 10 minutes from the start ofthe examination. The first system from the standardized production of the Cardiotom cameras is in the test phase.

The performance parameters (sensitivity, spatial and energy resolution, coincidence time resolution) of the full ring mini PET camera are comparable to other small animal PETsystems.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. p. 75
Series
Trita-STH : report, ISSN 1653-3836 ; 2010:1
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-12069 (URN)
Public defence
2010-03-19, KTH-Flemingsberg, Sal 3-221, Alfred Nobels Allé 10, Stockholm, 09:15 (English)
Opponent
Supervisors
Note
QC20100721Available from: 2010-03-02 Created: 2010-03-01 Last updated: 2010-07-21Bibliographically approved
Valastyán, I., Imrek, J., Hegyesi, G., Kalinka, G., Molnar, J., Novak, D., . . . Kerek, A. (2009). Experimental scanner setup from miniPET II detector module. In: 2008 IEEE Nuclear Science SYmposium Conference Record (pp. 3121-3124).
Open this publication in new window or tab >>Experimental scanner setup from miniPET II detector module
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2009 (English)In: 2008 IEEE Nuclear Science SYmposium Conference Record, 2009, p. 3121-3124Chapter in book (Other academic)
Abstract [en]

The PET technique is widely used in human clinical studies and recent developments of image resolution has made it suitable for small animal research. The second generation of our PET scanner consists of 12 detector modules and has a field of view large enough to image mice and rats. Parameters of the incoming data are extracted by Digital Signal Processing in the detector modules and a System-on-Module is used to transmit the data through an Ethernet network for storage and reconstruction. The experimental scanner setup described in this paper was constructed in order to investigate the applicability of the developed detector modules in a full ring small animal PET camera. The preliminary results of the system are also presented.

Series
IEEE NUCL SCI CONF REC, ISSN 1082-3654
Identifiers
urn:nbn:se:kth:diva-12066 (URN)000268656001250 ()978-1-4244-2714-7 (ISBN)
Note
QC20100710Available from: 2010-03-01 Created: 2010-03-01 Last updated: 2010-07-20Bibliographically approved
Valastyán, I., Imrek, J., Hegyesi, G., Molnar, J., Novak, D., Bone, D. & Kerek, A. (2007). Data acquisition and image reconstruction systems from the MiniPET scanners to the CARDIOTOM camera. In: Granja, C; Leroy, C; Stekl, I (Ed.), Nuclear Physics Methods And Accelerators In Biology And Medicine (pp. 282-283). American Institute of Physics (AIP), 958
Open this publication in new window or tab >>Data acquisition and image reconstruction systems from the MiniPET scanners to the CARDIOTOM camera
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2007 (English)In: Nuclear Physics Methods And Accelerators In Biology And Medicine / [ed] Granja, C; Leroy, C; Stekl, I, American Institute of Physics (AIP), 2007, Vol. 958, p. 282-283Chapter in book (Refereed)
Abstract [en]

Nuclear imaging devices play an important role in medical diagnosis as well as drug research. The first and second generation data acquisition systems and the image reconstruction library developed provide a unified hardware and software platform for the miniPET-I, miniPET-II small animal PET scanners and for the CARDIOTOM(TM).

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2007
Series
AIP Conference Proceedings, ISSN 0094-243X ; 958
Keywords
medical imaging, image reconstruction, data acquisition, small animal PET, gamma camera
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-12063 (URN)10.1063/1.2825817 (DOI)000252138700073 ()2-s2.0-71749121389 (Scopus ID)978-0-7354-0472-4 (ISBN)
Note

QC 20120906

Available from: 2010-03-01 Created: 2010-03-01 Last updated: 2020-03-05Bibliographically approved
Valastyán, I., Imrek, J., Molnár, J., Novák, D., Balkay, L., Emri, M., . . . Kerek, A. (2007). Full 3-D cluster-based iterative image reconstruction tool for a small animal PET camera. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 571(1-2), 219-222
Open this publication in new window or tab >>Full 3-D cluster-based iterative image reconstruction tool for a small animal PET camera
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2007 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 571, no 1-2, p. 219-222Article in journal (Refereed) Published
Abstract [en]

Iterative reconstruction methods are commonly used to obtain images with high resolution and good signal-to-noise ratio in nuclear imaging. The aim of this work was to develop a scalable, fast, cluster based, fully 3-D iterative image reconstruction package for our small animal PET camera, the miniPET. The reconstruction package is developed to determine the 3-D radioactivity distribution from list mode type of data sets and it can also simulate noise-free projections of digital phantoms. We separated the system matrix generation and the fully 3-D iterative reconstruction process. As the detector geometry is fixed for a given camera, the system matrix describing this geometry is calculated only once and used for every image reconstruction, making the process much faster. The Poisson and the random noise sensitivity of the ML-EM iterative algorithm were studied for our small animal PET system with the help of the simulation and reconstruction tool. The reconstruction tool has also been tested with data collected by the miniPET from a line and a cylinder shaped phantom and also a rat.

Keywords
Medical imaging, Image reconstruction, Small animal PET
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:kth:diva-6427 (URN)10.1016/j.nima.2006.10.067 (DOI)000244599100052 ()2-s2.0-33846356997 (Scopus ID)
Note
Accepted 2006 Published 2007 QC20100720Available from: 2006-11-27 Created: 2006-11-27 Last updated: 2017-12-14Bibliographically approved
Valastyán, I., Brodin, L.-Å., Elmqvist, H., Kerek, A., Molnar, J., Novak, D. & Ribbe, T. (2007). Gated tomographic imaging in ectomography using a dynamic heart phantom. In: Nuclear Science Symposium Conference Record, 2007. NSS '07. IEEE. Paper presented at IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC; Honolulu, HI; 27 October 2007 through 3 November 2007 (pp. 3414-3417). IEEE
Open this publication in new window or tab >>Gated tomographic imaging in ectomography using a dynamic heart phantom
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2007 (English)In: Nuclear Science Symposium Conference Record, 2007. NSS '07. IEEE, IEEE , 2007, p. 3414-3417Conference paper, Published paper (Refereed)
Abstract [en]

A new computer controlled dynamic heart phantom and the connection of an ECG unit to a tomographic gamma camera system, developed for ectomographic imaging, is presented. The phantom is used for validation of the camera. Measurements were performed to test the phantom as well as to study the feasibility of gated imaging in ectomography. The camera is intended for early diagnosis of myocardial and cerebral infarctions.

Place, publisher, year, edition, pages
IEEE, 2007
Series
IEEE Nuclear Science Symposium Conference Record, ISSN 1082-3654 ; 5
Keywords
Radiology, Nuclear Medicine & Medical Imaging
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-12060 (URN)10.1109/NSSMIC.2007.4436863 (DOI)000257380402177 ()2-s2.0-48349132721 (Scopus ID)978-1-4244-0922-8 (ISBN)
Conference
IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS-MIC; Honolulu, HI; 27 October 2007 through 3 November 2007
Note

QC 20120906

Available from: 2010-03-01 Created: 2010-03-01 Last updated: 2012-09-06Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5919-3554

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