Resolution properties of a prototype continuous miniature crystal element (cMiCE) scanner

Miyaoka, Robert S.; Li, Xiaoli; Pierce, Larry A.; McDougald, Wendy; Kinahan, Paul E.; Lewellen, T.K.

doi:10.1109/nssmic.2010.5874311

Cited by 6 publications

(3 citation statements)

References 36 publications

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“…The ML-based position reconstruction method requires a calibration procedure to estimate the forward model describing the expected response of the camera. Traditionally, this estimation was carried out through simulations [14] or complex scanning setups [15], which can be expensive and time consuming. For INSERT detection modules, the forward model used to determine the x,y coordinates of absorbed gamma rays assumes 2D Gaussian Light Response Functions (LRFs) [16].…”

Section: Doi Estimation Algorithm a Algorithm Overviewmentioning

confidence: 99%

A Statistical DOI Estimation Algorithm for a SiPM-Based Clinical SPECT Insert

DrAdda

Morahan

Carminati

et al. 2022

IEEE Trans. Radiat. Plasma Med. Sci.

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A prototype clinical brain SPECT insert has been designed for use in simultaneous SPECT/MRI. The system utilises novel slit-slat collimators which, like pinhole collimators, suffers from parallax errors due to the large incident angle of photons. A statistical algorithm has been developed to determine the depthof-interaction (DOI) with a view to improving image performance. The importance of DOI correction was demonstrated using Monte Carlo simulation. This simulation also indicated that 4 DOI layers (3×1.5 mm+3.5 mm) may be sufficient. The improvement in event localisation was demonstrated on a single detector before implementing the algorithm on the full clinical prototype where some limitations in event localisation in layers close to the readout plane were observed. Nevertheless DOI enabled the rejection of poorly localised events with improved resolution in reconstructed line sources.

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Section: Doi Estimation Algorithm a Algorithm Overviewmentioning

confidence: 99%

A Statistical DOI Estimation Algorithm for a SiPM-Based Clinical SPECT Insert

DrAdda

Morahan

Carminati

et al. 2022

IEEE Trans. Radiat. Plasma Med. Sci.

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“…The light sharing in an array of photodetectors allows the three-dimensional reconstruction of the scintillation event, with a high spatial resolution and depth of interaction positioning. By using monolithic crystals coupled to position sensitive photomultiplier tubes [ 16 ], to avalanche photodiodes [ 17 ] or to silicon photomultipliers (SiPM) [ 18 – 20 ], a spatial resolution close to the millimeter can be reached, and the depth of interaction can be reconstructed. Monolithic crystals coupled to a SiPM array can also reach the time resolution needed for time of flight applications [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Depth of interaction determination in monolithic scintillator with double side SiPM readout

et al. 2017

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BackgroundMonolithic scintillators read out by arrays of photodetectors represent a promising solution to obtain high spatial resolution and the depth of interaction (DOI) of the annihilation photon. We have recently investigated a detector geometry composed of a monolithic scintillator readout on two sides by silicon photomultiplier (SiPM) arrays, and we have proposed two parameters for the DOI determination: the difference in the number of triggered SiPMs on the two sides of the detector and the difference in the maximum collected signal on a single SiPM on each side. This work is focused on the DOI calibration and on the determination of the capability of our detector. For the DOI calibration, we studied a method which can be implemented also in detectors mounted in a full PET scanner. We used a PET detector module composed of a monolithic 20 × 20 × 10 mm3 LYSO scintillator crystal coupled on two opposite faces to two arrays of SiPMs. On each side, the scintillator was coupled to 6 × 6 SiPMs. In this paper, the two parameters previously proposed for the DOI determination were calibrated with two different methods. The first used a lateral scan of the detector with a collimated 511 keV pencil beam at steps of 0.5 mm to study the detector DOI capability, while the second used the background radiation of the 176Lu in the scintillator. The DOI determination capability was tested on different regions of the detector using each parameter and the combination of the two.ResultsWith both parameters for the DOI determination, in the lateral scan, the bias between the mean reconstructed DOI and the real beam position was lower than 0.3 mm, and the DOI distribution had a standard deviation of about 1.5 mm. When using the calibration with the radioactivity of the LYSO, the mean bias increased of about 0.2 mm but with no degradation of the standard deviation of the DOI distribution.ConclusionsThe two parameters allow to achieve a DOI resolution comparable with the state of the art, giving a continuous information about the three-dimensional interaction position of the scintillation. These results were obtained by using simple estimators and a detector scalable to a whole PET system. The DOI calibration obtained using lutetium natural radioactivity gives results comparable to the other standard method but appears more readily applicable to detectors mounted in a full PET scanner.

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“…En la Universidad de Washington se han desarrollado prototipos para PET basados tanto en detectores segmentados (dMiCE) como en detectores monolíticos (cMiCE) [149]. En [150] se encuentran resultados obtenidos con el concepto de detectores monolíticos cMiCE. El sistema de adquisición que se detalla en [149] está siendo utilizado para desarrollar un escáner preclínico y un escáner para mama.…”

Section: Comparación Con Prototipos Similaresunclassified

Detectores monolíticos y sensores compatibles con altos campos magnéticos para tomografía por emisión de positrones

Martín¹

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This thesis is focused on the development of experimental activities used to deepen the knowledge of monolithic detector blocks as an alternative to segmented detectors for Positron Emission Tomography (PET). It includes the development, characterization, setting up, running and evaluation of PET demonstrator prototypes with monolithic detector blocks of Cerium-doped Lutetium Yttrium Orthosilicate (LYSO:Ce) using magnetically compatible sensors such as Avalanche Photodiodes (APDs) and Silicon Photomultipliers (SiPMs).The prototypes implemented with APDs were constructed to validate the viability of a high-sensitivity PET prototype that had previously been simulated, denominated BrainPET. This work describes and characterizes the integrated front-end electronics used in these prototypes, as well as the electronic readout system developed especially for them. It shows the experimental set-ups to obtain the tomographic PET images and to train neural networks algorithms used for position estimation of photons impinging on the surface of monolithic blocks.Using the BrainPET prototype, satisfactory energy resolution (13 % FWHM), spatial precision of monolithic blocks (~ 2 mm FWHM) and spatial resolution of the PET image (1.5 -1.7 mm FWHM) in the center of the Field of View (FoV) were obtained. Moreover, we proved the imaging capabilities of this demonstrator with extended sources, considering the acquisition of two simultaneous sources of 1 mm diameter placed at known distances. However, some important limitations were also detected with the BrainPET prototype. In the first place, it was confirmed that there was a lack of flexibility working with an Application Specific Integrated Circuit (ASIC) whose electronic design was not own but commercial, along with the high cost required to modify an ASIC design with such features. Furthermore, the final characterization of the BrainPET ASIC showed a timing resolution with room for improvement (~ 13 ns FWHM).Taking into consideration the limitations obtained with the BrainPET prototype, along with the technological evolution in magnetically compatible devices, the knowledge acquired with the monolithic blocks were transferred to the new technology iv available, the SiPMs. Moreover, we opted for a new strategy in the front-end electronics, the FlexToT ASIC, an own design ASIC based on a Time over Threshold (ToT) scheme. One of the most interesting features underlying a ToT architecture is the encoding of the analog input signal amplitude information into the duration of the output signals, delivering directly digital pulses. The electronic architecture helps substitute the Analog to Digital Converters (ADCs) for Time to Digital Converters (TDCs), and they are easily implemented in Field Programmable Gate Arrays (FPGA), reducing the consumption and the complexity of the design.A new prototype demonstrator based on SiPMs was implemented to validate the FlexToT ASIC for monolithic or segmented blocks. The design and characterization of the necessary front-end electronic to read-ou...

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Resolution properties of a prototype continuous miniature crystal element (cMiCE) scanner

Cited by 6 publications

References 36 publications

A Statistical DOI Estimation Algorithm for a SiPM-Based Clinical SPECT Insert

A Statistical DOI Estimation Algorithm for a SiPM-Based Clinical SPECT Insert

Depth of interaction determination in monolithic scintillator with double side SiPM readout

Detectores monolíticos y sensores compatibles con altos campos magnéticos para tomografía por emisión de positrones

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