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Author Studen, A.; Brzezinski, K.; Chesi, E.; Cindro, V.; Clinthorne, N.H.; Cochran, E.; Grosicar, B.; Grkovski, M.; Honscheid, K.; Kagan, H.; Lacasta, C.; Llosa, G.; Mikuz, M.; Stankova, V.; Weilhammer, P.; Zontar, D.
Title Silicon detectors for combined MR-PET and MR-SPECT imaging Type Journal Article
Year 2013 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 702 Issue Pages 88-90
Keywords PET; Silicon detectors; SPECT
Abstract Silicon based devices can extend PET-MR and SPECT-MR imaging to applications, where their advantages in performance outweigh benefits of high statistical counts. Silicon is in many ways an excellent detector material with numerous advantages, among others: excellent energy and spatial resolution, mature processing technology, large signal to noise ratio, relatively low price, availability, versatility and malleability. The signal in silicon is also immune to effects of magnetic field at the level normally used in MR devices. Tests in fields up to 7 T were performed in a study to determine effects of magnetic field on positron range in a silicon PET device. The curvature of positron tracks in direction perpendicular to the field's orientation shortens the distance between emission and annihilation point of the positron. The effect can be fully appreciated for a rotation of the sample for a fixed field direction, compressing range in all dimensions. A popular Ga-68 source was used showing a factor of 2 improvement in image noise compared to zero field operation. There was also a little increase in noise as the reconstructed resolution varied between 2.5 and 1.5 mm. A speculative applications can be recognized in both emission modalities, SPECT and PET. Compton camera is a subspecies of SPECT, where a silicon based scatter as a MR compatible part could inserted into the MR bore and the secondary detector could operate in less constrained environment away from the magnet. Introducing a Compton camera also relaxes requirements of the radiotracers used, extending the range of conceivable photon energies beyond 140.5 keV of the Tc-99m. In PET, one could exploit the compressed sub-millimeter range of positrons in the magnetic field. To exploit the advantage, detectors with spatial resolution commensurate to the effect must be used with silicon being an excellent candidate. Measurements performed outside of the MR achieving spatial resolution below 1 mm are reported.
Address [Studen, A.; Cindro, V.; Grosicar, B.; Grkovski, M.; Mikuz, M.; Zontar, D.] Jozef Stefan Inst, Ljubljana, Slovenia, Email: andrej.studen@ijs.si
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue (up) Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000314682300026 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1331
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Author Grkovski, M.; Brzezinski, K.; Cindro, V.; Clinthorne, N.H.; Kagan, H.; Lacasta, C.; Mikuz, M.; Solaz, C.; Studen, A.; Weilhammer, P.; Zontar, D.
Title Evaluation of a high resolution silicon PET insert module Type Journal Article
Year 2015 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 788 Issue Pages 86-94
Keywords Positron emission tomography; Silicon detectors; PET insert; Image reconstruction
Abstract Conventional PET systems can be augmented with additional detectors placed in close proximity of the region of interest. We developed a high resolution PET insert module to evaluate the added benefit of such a combination. The insert module consists of two back-to-back 1 mm thick silicon sensors, each segmented into 1040 1 mm(2) pads arranged in a 40 by 26 array. A set of 16 VATAGP7.1 ASICs and a custom assembled data acquisition board were used to read out the signal from the insert module. Data were acquired in slice (20) geometry with a Jaszczak phantom (rod diameters of 12-4.8 mm) Filled with F-18-FDG and the images were reconstructed with ML-EM method. Both data with full and limited angular coverage from the insert module were considered and three types of coincidence events were combined. The ratio of high-resolution data that substantially improves quality of the reconstructed image for the region near the surface of the insert module was estimated to be about 4%. Results from our previous studies suggest that such ratio could be achieved at a moderate technological expense by using an equivalent of two insert modules (an effective sensor thickness of 4 mm).
Address [Grkovski, Milan; Cindro, Vladimir; Mikuz, Marko; Studen, Andrej; Zontar, Dejan] Jozef Stefan Inst, Ljubljana, Slovenia, Email: milan.grkovski@ijs.si
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue (up) Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000354870700016 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2232
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Author Hiti, B.; Cindro, V.; Gorisek, A.; Franks, M.; Marco-Hernandez, R.; Kramberger, G.; Mandic, I.; Mikuz, M.; Powell, S.; Steininger, H.; Vilella, E.; Zavrtanik, M.; Zhang, C.
Title Characterisation of analogue front end and time walk in CMOS active pixel sensor Type Journal Article
Year 2021 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.
Volume 16 Issue 12 Pages P12020 - 12pp
Keywords Charge induction; Radiation-hard detectors; Solid state detectors
Abstract In this work we investigated a method to determine time walk in an active silicon pixel sensor prototype using Edge-TCT with infrared laser charge injection. Samples were investigated before and after neutron irradiation to 5 . 10(14) n(eq)/cm(2). Threshold, noise and calibration of the analogue front end were determined with external charge injection. A spatially sensitive measurement of collected charge and time walk was carried out with Edge-TCT, showing a uniform charge collection and output delay in pixel centre. On pixel edges charge sharing was observed due to finite beam width resulting in smaller signals and larger output delay. Time walk below 25 ns was observed for charge above 2000 e(-) at a threshold above the noise level. Time walk measurement with external charge injection yielded identical results.
Address [Hiti, B.; Cindro, V.; Gorisek, A.; Kramberger, G.; Mandic, I.; Mikuz, M.; Zavrtanik, M.] Jozef Stefan Inst, Jamova Cesta 39, Ljubljana, Slovenia, Email: bojan.hiti@ijs.si
Corporate Author Thesis
Publisher IOP Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue (up) Edition
ISSN 1748-0221 ISBN Medium
Area Expedition Conference
Notes WOS:000758055400055 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5138
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Author Mandic, I.; Cindro, V.; Debevc, J.; Gorisek, A.; Hiti, B.; Kramberger, G.; Skomina, P.; Zavrtanik, M.; Mikuz, M.; Vilella, E.; Zhang, C.; Powell, S.; Franks, M.; Marco-Hernandez, R.; Steininger, H.
Title Study of neutron irradiation effects in Depleted CMOS detector structures Type Journal Article
Year 2022 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.
Volume 17 Issue 3 Pages P03030 - 13pp
Keywords Particle tracking detectors (Solid-state detectors); Si microstrip and pad detectors; Solid state detectors
Abstract In this paper the results of Edge-TCT and I-V measurements with passive test structures made in LFoundry 150 nm HV-CMOS process on p-type substrates with different initial resistivities ranging from 0.5 to 3 k Omega cm are presented. Samples were irradiated with reactor neutrons up to a fluence of 2.10(15) n(eq)/cm(2). The depletion depth was measured with Edge-TCT. The effective space charge concentration N-eff was estimated from the dependence of the depletion depth on bias voltage and studied as a function of neutron fluence. The dependence of N-eff on fluence changes with initial acceptor concentration in agreement with other measurements with p-type silicon. A long term accelerated annealing study of N-eff and detector current up to 1280 minutes at 60 degrees C was made. It was found that N-eff and current in reverse biased detector behave as expected for irradiated silicon.
Address [Mandic, I; Cindro, V; Debevc, J.; Gorisek, A.; Hiti, B.; Kramberger, G.; Skomina, P.; Zavrtanik, M.; Mikuz, M.] Jozef Stefan Inst, Jamova 39, Ljubljana, Slovenia, Email: igor.mandic@ijs.si
Corporate Author Thesis
Publisher IOP Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue (up) Edition
ISSN 1748-0221 ISBN Medium
Area Expedition Conference
Notes WOS:000784713600004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5208
Permanent link to this record