scholarly journals Design and system evaluation of a dual-panel portable PET (DP-PET)

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tianyi Zeng ◽  
Jiaxu Zheng ◽  
Xinyuan Xia ◽  
Xin Chen ◽  
Beien Wang ◽  
...  
Keyword(s):  
Image Quality ◽  
High Sensitivity ◽  
Whole Body ◽  
Clinical Settings ◽  
Reconstruction Method ◽  
Digital Readout ◽  
Battery Power ◽  
Measurement Results ◽  
Pet Reconstruction ◽  
Initial Results

Abstract Background Integrated whole-body PET/MR technology continues to mature and is now extensively used in clinical settings. However, due to the special design architecture, integrated whole-body PET/MR comes with a few inherent limitations. Firstly, whole-body PET/MR lacks sensitivity and resolution for focused organs. Secondly, broader clinical access of integrated PET/MR has been significantly restricted due to its prohibitively high cost. The MR-compatible PET insert is an independent and removable PET scanner which can be placed within an MRI bore. However, the mobility and configurability of all existing MR-compatible PET insert prototypes remain limited. Methods An MR-compatible portable PET insert prototype, dual-panel portable PET (DP-PET), has been developed for simultaneous PET/MR imaging. Using SiPM, digital readout electronics, novel carbon fiber shielding, phase-change cooling, and MRI compatible battery power, DP-PET was designed to achieve high-sensitivity and high-resolution with compatibility with a clinical 3-T MRI scanner. A GPU-based reconstruction method with resolution modeling (RM) has been developed for the DP-PET reconstruction. We evaluated the system performance on PET resolution, sensitivity, image quality, and the PET/MR interference. Results The initial results reveal that the DP-PET prototype worked as expected in the MRI bore and caused minimal compromise to the MRI image quality. The PET performance was measured to show a spatial resolution ≤ 2.5 mm (parallel to the detector panels), maximum sensitivity = 3.6% at the center of FOV, and energy resolution = 12.43%. MR pulsing introduces less than 2% variation to the PET performance measurement results. Conclusions We developed a MR-compatible PET insert prototype and performed several studies to begin to characterize the performance of the proposed DP-PET. The results showed that the proposed DP-PET performed well in the MRI bore and would cause little influence on the MRI images. The Derenzo phantom test showed that the proposed reconstruction method could obtain high-quality images using DP-PET.

scholarly journals Design and System Evaluation of a Dual-Panel Portable PET (DP-PET)

2021 ◽  
Author(s):  
Tianyi Zeng ◽  
Jiaxu Zheng ◽  
Xinyuan Xia ◽  
Xin Chen ◽  
Beien Wang ◽  
...  
Keyword(s):  
Image Quality ◽  
Low Cost ◽  
High Sensitivity ◽  
Whole Body ◽  
Reconstruction Method ◽  
Digital Readout ◽  
Battery Power ◽  
Measurement Results ◽  
Pet Reconstruction ◽  
Initial Results

Abstract Background: Integrated whole-body PET/MR technology continues to mature and is now extensively used in clinical setting. However, due to the special design architecture, integrated whole-body PET/MR comes with a few inherent limitations. Firstly, whole-body PET/MR lacks sensitivity and resolution for focused organs. Secondly, boarder clinical access of integrated PET/MR has been significantly restricted due to its prohibitively high cost. The MR-compatible PET insert is a low cost and flexible PET scanner which can be placed within an MRI bore. However, mobility and configurability of all existing MR-compatible PET insert prototypes remain limited. Methods: An MR-compatible portable PET insert prototype, Dual-panel Portable PET (DP-PET), has been developed for simultaneous PET/MR imaging. Using SiPM, digital readout electronics, novel carbon fiber shielding, phase-change cooling and MRI compatible battery power, DP-PET was designed to achieve high-sensitivity and high-resolution with compatibility with a clinical 3T MRI scanner. A GPU-based reconstruction method with Resolution Modelling (RM) has been developed for the DP-PET reconstruction. We evaluated the system performance on PET resolution, sensitivity, image quality and the PET/MR interference. Results: Initial results reveal that the DP-PET prototype worked as expected in the MRI bore and caused minimal compromise to the MRI image quality. The PET performance was measured to show a spatial resolution <= 2mm (parallel to the detector panels), maximum sensitivity =3.6% at the center of FOV and energy resolution = 12.43%. MRI pulsing introduces less than 1% variation to the PET performance measurement results. Conclusions: We developed a MR-compatible PET insert prototype and performed several studies to begin to characterize the performance of the proposed DP-PET.The results showed that the proposed DP-PET performed well in the MRI bore and would cause little influence on the MRI images. The Derenzo phantom test showed that the proposed reconstruction method could obtained high quality images using DP-PET.

scholarly journals Initial results from a prototype whole-body photon-counting computed tomography system

2015 ◽  
Author(s):  
Z. Yu ◽  
S. Leng ◽  
S. M. Jorgensen ◽  
Z. Li ◽  
R. Gutjahr ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Photon Counting ◽  
Whole Body ◽  
Tomography System ◽  
Initial Results

scholarly journals Significant artefactual noise in 90Y TOF-PET imaging of low specific activity phantoms arises despite increased acquisition time

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Michel Hesse ◽  
Stephan Walrand
Keyword(s):  
Pet Imaging ◽  
Specific Activity ◽  
Whole Body ◽  
Acquisition Time ◽  
Random Coincidence ◽  
Natural Crystal ◽  
Phantom Studies ◽  
Pet Reconstruction ◽  
Very High ◽  
Tof Pet

AbstractVolumes of usual PET phantoms are about four to sixfold that of a human liver. In order to avoid count rate saturation and handling of very high 90Y activity, reported TOF-PET phantom studies are performed using specific activities lower than those observed in liver radioembolization.However, due to the constant random coincidence rate induced by the natural crystal radioactivity, reduction of 90Y specific activity in TOF-PET imaging cannot be counterbalanced by increasing the acquisition time. As a result, most 90Y phantom studies reported images noisier than those obtained in whole-body 18F-FDG, and thus advised to use dedicated noise control in TOF-PET imaging post 90Y liver radioembolization.We performed acquisitions of the Jaszczak Deluxe phantom in which the hot rod insert was only partially filled with 2.6 GBq of 90Y. Standard reconstruction parameters recommended by the manufacturer for whole-body 18F-FDG PET were used.Low specific activity setups, although exactly compensated by increasing the acquisition time in order to get the same number of detected true coincidences per millilitre, were impacted by significant noise. On the other hand, specific activity and acquisition time setup similar to that used in post 90Y liver radioembolization provided image quality very close to that of whole-body 18F-FDG.This result clearly discards the use of low specific activity phantoms intended to TOF-PET reconstruction parameter optimization. Volume reduction of large phantoms can be achieved by vertically setting the phantoms or by adding Styrofoam inserts.

scholarly journals Threshold-dependent iodine imaging and spectral separation in a whole-body photon-counting CT system

2021 ◽  
Author(s):  
S. Sawall ◽  
L. Klein ◽  
E. Wehrse ◽  
L. T. Rotkopf ◽  
C. Amato ◽  
...  
Keyword(s):  
Image Quality ◽  
Photon Counting ◽  
Dual Energy ◽  
Whole Body ◽  
Dual Energy Ct ◽  
Post Mortem ◽  
Tube Voltage ◽  
Spectral Separation ◽  
Dual Source ◽  
Noise Ratio

Abstract Objective To evaluate the dual-energy (DE) performance and spectral separation with respect to iodine imaging in a photon-counting CT (PCCT) and compare it to dual-source CT (DSCT) DE imaging. Methods A semi-anthropomorphic phantom extendable with fat rings equipped with iodine vials is measured in an experimental PCCT. The system comprises a PC detector with two energy bins (20 keV, T) and (T, eU) with threshold T and tube voltage U. Measurements using the PCCT are performed at all available tube voltages (80 to 140 kV) and threshold settings (50–90 keV). Further measurements are performed using a conventional energy-integrating DSCT. Spectral separation is quantified as the relative contrast media ratio R between the energy bins and low/high images. Image noise and dose-normalized contrast-to-noise ratio (CNRD) are evaluated in resulting iodine images. All results are validated in a post-mortem angiography study. Results R of the PC detector varies between 1.2 and 2.6 and increases with higher thresholds and higher tube voltage. Reference R of the EI DSCT is found as 2.20 on average overall phantoms. Maximum CNRD in iodine images is found for T = 60/65/70/70 keV for 80/100/120/140 kV. The highest CNRD of the PCCT is obtained using 140 kV and is decreasing with decreasing tube voltage. All results could be confirmed in the post-mortem angiography study. Conclusion Intrinsically acquired DE data are able to provide iodine images similar to conventional DSCT. However, PCCT thresholds should be chosen with respect to tube voltage to maximize image quality in retrospectively derived image sets. Key Points • Photon-counting CT allows for the computation of iodine images with similar quality compared to conventional dual-source dual-energy CT. • Thresholds should be chosen as a function of the tube voltage to maximize iodine contrast-to-noise ratio in derived image sets. • Image quality of retrospectively computed image sets can be maximized using optimized threshold settings.

A Color-Doppler Shear-Wave-Imaging Phase-reconstruction Method Using Four Color Flow Images

2016 ◽  
Vol 39 (3) ◽  
pp. 172-188
Author(s):  
Naoki Sunaguchi ◽  
Yoshiki Yamakoshi ◽  
Takahito Nakajima
Keyword(s):  
Image Quality ◽  
Shear Wave ◽  
Initial Phase ◽  
Color Doppler ◽  
Reconstruction Method ◽  
Phase Reconstruction ◽  
Color Flow ◽  
Shear Wave Imaging ◽  
Wave Imaging ◽  
Phase Map

This study investigates shear wave phase map reconstruction using a limited number of color flow images (CFIs) acquired with a color Doppler ultrasound imaging instrument. We propose an efficient reconstruction method to considerably reduce the number of CFIs required for reconstruction and compare this method with Fourier analysis-based color Doppler shear wave imaging. The proposed method uses a two-step phase reconstruction process, including an initial phase map derived from four CFIs using an advanced iterative algorithm of optical interferometry. The second step reduces phase artifacts in the initial phase map using an iterative correction procedure that cycles between the Fourier and inverse Fourier domains while imposing directional filtering and total variation regularization. We demonstrate the efficacy of this method using synthetic and experimental data of a breast phantom and human breast tissue. Our results show that the proposed method maintains image quality and reduces the number of CFIs required to four; previous methods have required at least 32 CFIs to achieve equivalent image quality. The proposed method is applicable to real-time shear wave elastography using a continuous shear wave produced by a mechanical vibrator.

scholarly journals Simulated Radiation Dose Reduction in Whole-Body CT on a 3rd Generation Dual-Source Scanner: An Intraindividual Comparison

Diagnostics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 118
Author(s):  
Andreas S. Brendlin ◽  
Moritz T. Winkelmann ◽  
Phuong Linh Do ◽  
Vincent Schwarze ◽  
Felix Peisen ◽  
...  
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Whole Body ◽  
Reference Standard ◽  
Diagnostic Confidence ◽  
Effective Radiation Dose ◽  
Intraindividual Comparison ◽  
Dual Source ◽  
Effective Radiation

To evaluate the effect of radiation dose reduction on image quality and diagnostic confidence in contrast-enhanced whole-body computed tomography (WBCT) staging. We randomly selected March 2016 for retrospective inclusion of 18 consecutive patients (14 female, 60 ± 15 years) with clinically indicated WBCT staging on the same 3rd generation dual-source CT. Using low-dose simulations, we created data sets with 100, 80, 60, 40, and 20% of the original radiation dose. Each set was reconstructed using filtered back projection (FBP) and Advanced Modeled Iterative Reconstruction (ADMIRE®, Siemens Healthineers, Forchheim, Germany) strength 1–5, resulting in 540 datasets total. ADMIRE 2 was the reference standard for intraindividual comparison. The effective radiation dose was calculated using commercially available software. For comparison of objective image quality, noise assessments of subcutaneous adipose tissue regions were performed automatically using the software. Three radiologists blinded to the study evaluated image quality and diagnostic confidence independently on an equidistant 5-point Likert scale (1 = poor to 5 = excellent). At 100%, the effective radiation dose in our population was 13.3 ± 9.1 mSv. At 20% radiation dose, it was possible to obtain comparably low noise levels when using ADMIRE 5 (p = 1.000, r = 0.29). We identified ADMIRE 3 at 40% radiation dose (5.3 ± 3.6 mSv) as the lowest achievable radiation dose with image quality and diagnostic confidence equal to our reference standard (p = 1.000, r > 0.4). The inter-rater agreement for this result was almost perfect (ICC ≥ 0.958, 95% CI 0.909–0.983). On a 3rd generation scanner, it is feasible to maintain good subjective image quality, diagnostic confidence, and image noise in single-energy WBCT staging at dose levels as low as 40% of the original dose (5.3 ± 3.6 mSv), when using ADMIRE 3.

scholarly journals Photogrammetric Digital Surface Model Reconstruction in Extreme Low-Light Environments

2021 ◽  
Vol 13 (7) ◽  
pp. 1261
Author(s):  
Riccardo Roncella ◽  
Nazarena Bruno ◽  
Fabrizio Diotri ◽  
Klaus Thoeni ◽  
Anna Giacomini
Keyword(s):  
Image Quality ◽  
Image Quality Assessment ◽  
High Sensitivity ◽  
Sensor Technology ◽  
Surface Model ◽  
Night Time ◽  
Low Light ◽  
Reduction Techniques ◽  
Geometrical Information ◽  
Imaging Sensors

Digital surface models (DSM) have become one of the main sources of geometrical information for a broad range of applications. Image-based systems typically rely on passive sensors which can represent a strong limitation in several survey activities (e.g., night-time monitoring, underground survey and night surveillance). However, recent progresses in sensor technology allow very high sensitivity which drastically improves low-light image quality by applying innovative noise reduction techniques. This work focuses on the performances of night-time photogrammetric systems devoted to the monitoring of rock slopes. The study investigates the application of different camera settings and their reliability to produce accurate DSM. A total of 672 stereo-pairs acquired with high-sensitivity cameras (Nikon D800 and D810) at three different testing sites were considered. The dataset includes different camera configurations (ISO speed, shutter speed, aperture and image under-/over-exposure). The use of image quality assessment (IQA) methods to evaluate the quality of the images prior to the 3D reconstruction is investigated. The results show that modern high-sensitivity cameras allow the reconstruction of accurate DSM in an extreme low-light environment and, exploiting the correct camera setup, achieving comparable results to daylight acquisitions. This makes imaging sensors extremely versatile for monitoring applications at generally low costs.

scholarly journals Source reconstruction for bioluminescence tomography via L1∕2 regularization

2018 ◽  
Vol 11 (02) ◽  
pp. 1750014 ◽  
Author(s):  
Jingjing Yu ◽  
Qiyue Li ◽  
Haiyu Wang
Keyword(s):  
Image Quality ◽  
Matching Pursuit ◽  
Imaging Modality ◽  
Reconstruction Algorithm ◽  
Reconstruction Method ◽  
Reconstruction Algorithms ◽  
Preclinical Research ◽  
Bioluminescence Tomography ◽  
Comparison Results ◽  
Stable Reconstruction

Bioluminescence tomography (BLT) is an important noninvasive optical molecular imaging modality in preclinical research. To improve the image quality, reconstruction algorithms have to deal with the inherent ill-posedness of BLT inverse problem. The sparse characteristic of bioluminescent sources in spatial distribution has been widely explored in BLT and many L1-regularized methods have been investigated due to the sparsity-inducing properties of L1 norm. In this paper, we present a reconstruction method based on L[Formula: see text] regularization to enhance sparsity of BLT solution and solve the nonconvex L[Formula: see text] norm problem by converting it to a series of weighted L1 homotopy minimization problems with iteratively updated weights. To assess the performance of the proposed reconstruction algorithm, simulations on a heterogeneous mouse model are designed to compare it with three representative sparse reconstruction algorithms, including the weighted interior-point, L1 homotopy, and the Stagewise Orthogonal Matching Pursuit algorithm. Simulation results show that the proposed method yield stable reconstruction results under different noise levels. Quantitative comparison results demonstrate that the proposed algorithm outperforms the competitor algorithms in location accuracy, multiple-source resolving and image quality.

scholarly journals Prototype Sistem Deteksi Partial Discharge Pada Isolasi Kabel Menggunakan Sensor Microphone (Prototype Of Partial Discharge Detection System In Cable Isolation Using Microphone Sensor)

2019 ◽  
Vol 3 (2) ◽  
pp. 206
Author(s):  
Mochamad Zaeynuri Setiawan ◽  
Fachrudin Hunaini ◽  
Mohamad Mukhsim
Keyword(s):  
Detection System ◽  
Partial Discharge ◽  
Measurement Data ◽  
Negative Ions ◽  
High Sensitivity ◽  
Sound Waves ◽  
Cable Insulation ◽  
Insulation Failure ◽  
Measurement Results ◽  
Discharge Detection

The phenomenon that often arises in a substation is the problem of partial discharge in outgoing cable insulation. Partial discharge is a jump of positive and negative ions that are not supposed to meet so that it can cause a spark jump. If a partial discharge is left too long it can cause insulation failure, the sound of snakes like hissing and the most can cause a flashover on the outgoing cable. Then a partial discharge detection prototype was made in the cable insulation in order to anticipate the isolation interference in the outgoing cable. Can simplify the work of substation operators to check the reliability of insulation on the outgoing side of each cubicle. So it was compiled as a method for measuring sound waves caused by partial discharge in the process of measuring using a microphone sensor, the Arduino Mega 2560 module as a microcontroller, the LCD TFT as a monitoring and the MicroSD card module as its storage. The microphone sensor is a sensor that has a high sensitivity to sound, has 2 analog and digital readings, and is easily designed with a microcontroller. Basically the unit of measure measured at partial discharge is Decibels. The results of the prototype can be applied to the cubicle and the way it works is to match the prototype to the outgoing cubicle cable then measure from the cable boots connector to the bottom of the outgoing cable with a distance of 1 meter. Then the measurement results will be monitored on the TFT LCD screen in the form of measurement results, graphs and categories on partial discharge. In this design the measurement data made by the microphone can be stored with microSD so that it can make an evaluation of partial discharge handling in outgoing cable insulation.

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