Potential applications of electron emission membranes in medicine

Bilevych, Y.; Brünner, Stefan; Chan, Hong; Charbon, Edoardo; Graaf, H. van der; Hagen, C. W.; Nützel, Gert; Pinto, Sergio D.; Prodanović, V.; Rotman, Daan; Santagata, F.; Sarro, Lina; Schaart, Dennis R.; Sinsheimer, John; Smedley, J.; Tao, Shuxia; Theulings, A. M. M. G.

doi:10.1016/j.nima.2015.10.084

Cited by 8 publications

(12 citation statements)

References 18 publications

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“…that the development of photosensors with extremely good SPTR as well as PDE might facilitate the realization of TOF-PET detectors based on pure Cherenkov radiators in future (Bilevych et al 2016). As another potential solution, Brunner et al proposed to combine event timing based on Cherenkov emission with energy discrimination based on scintillation in a hybrid scintillator/Cherenkov radiator , Brunner 2014.…”

Section: Cherenkov Effect For Tof-petmentioning

confidence: 99%

BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET

2017

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Due to detector developments in the last decade, the time-of-flight (TOF) method is now commonly used to improve the quality of positron emission tomography (PET) images. Clinical TOF-PET systems based on L(Y)SO:Ce crystals and silicon photomultipliers (SiPMs) with coincidence resolving times (CRT) between 325 ps and 400 ps FWHM have recently been developed. Before the introduction of L(Y)SO:Ce, BGO was used in many PET systems. In addition to a lower price, BGO offers a superior attenuation coefficient and a higher photoelectric fraction than L(Y)SO:Ce. However, BGO is generally considered an inferior TOF-PET scintillator. In recent years, TOF-PET detectors based on the Cherenkov effect have been proposed. However, the low Cherenkov photon yield in the order of ∼10 photons per event complicates energy discrimination-a severe disadvantage in clinical PET. The optical characteristics of BGO, in particular its high transparency down to 310 nm and its high refractive index of ∼2.15, are expected to make it a good Cherenkov radiator. Here, we study the feasibility of combining event timing based on Cherenkov emission with energy discrimination based on scintillation in BGO, as a potential approach towards a cost-effective TOF-PET detector. Rise time measurements were performed using a timecorrelated single photon counting (TCSPC) setup implemented on a digital photon counter (DPC) array, revealing a prompt luminescent component likely to be due to Cherenkov emission. Coincidence timing measurements were performed using BGO crystals with a cross-section of 3 mm × 3 mm and five different lengths between 3 mm and 20 mm, coupled to DPC arrays. NonGaussian coincidence spectra with a FWHM of 200 ps were obtained with the 27 mm 3 BGO cubes, while FWHM values as good as 330 ps were achieved Institute of Physics and Engineering in MedicineOriginal content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. with the 20 mm long crystals. The FWHM value was found to improve with decreasing temperature, while the FWTM value showed the opposite trend.

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Section: Cherenkov Effect For Tof-petmentioning

confidence: 99%

BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET

2017

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“…Meanwhile, the advantages of smaller, less costly systems have provided opportunities for researchers to develop versatile MEMS devices. One of these MEMS based devices is a novel photon detector with a goal of ps temporal resolution proposed by H. van der Graaf [6] at NIKHEF, Amsterdam. The photon detector (called Tipsy) being developed has the potential to revolutionize photon detection with its superb temporal resolution.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, there are few systematic studies on the electron energy loss mechanism in silicon nitride. Within the research group of H. van der Graaf [6], recent efforts have been made in this matter by using a Monte Carlo code based on the Geant4 platform of CERN [12], which is developed by Bosch and Kieft [13]. This code is one of few with a good description of low-energy (<50 eV) interactions of electrons with matter.…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of Silicon-Rich Silicon Nitride (SixNyHz) from First Principles

et al. 2015

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Abstract:The real and imaginary parts of the complex refractive index of SixNyHz have been calculated from first principles. Optical spectra for reflectivity, absorption coefficient, energy-loss function (ELF), and refractive index were obtained. The results for Si3N4 are in agreement with the available theoretical and experimental results. To understand the electron energy loss mechanism in Si-rich silicon nitride, the influence of the Si/N ratio, the positions of the access Si atoms, and H in and on the surface of the ELF have been investigated. It has been found that all defects, such as dangling bonds in the bulk and surfaces, increase the intensity of the ELF in the low energy range (below 10 eV). H in the bulk and on the surface has a healing effect, which can reduce the intensity of the loss peaks by saturating the dangling bonds. Electronic structure analysis has confirmed the origin of the changes in the ELF. It has demonstrated that the changes in ELF are not only affected by the composition but also by the microstructures of the materials. The results can be used to tailor the optical properties, in this case the ELF of Si-rich Si3N4, which is essential for secondary electron emission applications.

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“…Finally, these new planar detectors can be light, thin and flat, permitting, for instance, the hermetic readout of all six sides of a scintillating cube. The core innovation, namely the stacked curved dynodes on top of a pixel chip, forming a light, compact and planar device, is also relevant for solid state, atomic and molecular physics experiments, for medical imaging (Cherenkov-PET [5]), and may have commercial applications such as prompt 3D optical imaging (machine viewing, driverless driving). The Tynode.…”

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confidence: 99%

The Tynode: A new vacuum electron multiplier

Graaf

Akhtar

Budko

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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By placing, in vacuum, a stack of transmission dynodes (tynodes) on top of a CMOS pixel chip, a single free electron detector could be made with outstanding performance in terms of spatial and time resolution. The essential object is the tynode: an ultra thin membrane, which emits, at the impact of an energetic electron on one side, a multiple of electrons at the other side. The electron yields of tynodes have been calculated by means of GEANT-4 Monte Carlo simulations, applying special lowenergy extensions. The results are in line with another simulation based on a continuous charge-diffusion model. By means of Micro Electro Mechanical System (MEMS) technology, tynodes and test samples have been realised. The secondary electron yield of several samples has been measured in three different setups. Finally, several possibilities to improve the yield are presented.

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Potential applications of electron emission membranes in medicine

Cited by 8 publications

References 18 publications

BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET

BGO as a hybrid scintillator / Cherenkov radiator for cost-effective time-of-flight PET

Optical Properties of Silicon-Rich Silicon Nitride (SixNyHz) from First Principles

The Tynode: A new vacuum electron multiplier

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