Image Reconstruction Software Research Articles

Single-molecule localization microscopy at 2.4-fold resolution improvement with optical lattice pattern illumination

Traditional camera-based single-molecule localization microscopy (SMLM), with its high imaging resolution and localization throughput, has made significant advancements in biological and chemical researches. However, due to the limitation of the fluorescence signal-to-noise ratio (SNR) of a single molecule, its resolution is difficult to reach to 5 nm. Optical lattice produces a nondiffracting beam pattern that holds the potential to enhance microscope performance through its high contrast and penetration depth. Here, we propose a new method named LatticeFLUX which utilizes the wide-field optical lattice pattern illumination for individual molecule excitation and localization. We calculated the Cramér-Rao lower bound of LatticeFLUX resolution and proved that our method can improve the single molecule localization precision by 2.4 times compared with the traditional SMLM. We propose a scheme using 9-frame localization, which solves the problem of uneven lattice light illumination. Based on the experimental single-molecule fluorescence SNR, we coded the image reconstruction software to further verify the resolution enhancement capability of LatticeFLUX on simulated punctate DNA origami, line pairs, and cytoskeleton. LatticeFLUX confirms the feasibility of using 2D structured light illumination to obtain high single-molecule localization precision under high localization throughput. It paves the way for further implementation of ultra-high resolution full 3D structured-light-illuminated SMLM.

Field camera input to virtual phantom (ViP) scanner acquisitions for quality assurance of derived MRI quantities: first implementation and proof-of-principle.

Quality assurance (QA) of measurements derived from MRI can require complicated test phantoms. This work introduces a new QA concept using gradient and transmit RF recordings by a limited field camera (FC) to govern the previous Virtual Phantom (ViP) method. The purpose is to describe the first technical implementation of combined FC+ViP, and illustrate its performance in examples, including quantitative first-pass myocardial perfusion. The new QA concept starts with a synthetic test object (STO) representing some arbitrary test input. Using recordings of the unmodified standard sequence by a gradient and RF waveform camera (FC), ViP calculates by Bloch simulation the continuous RF signal emitted by the STO during this sequence (hence FC+ViP). During nominally identical repetition of the sequence acquisition, ViP transmits the RF signal for scanner reception, reconstruction and any further parametric derivations by the unmodified standard scanner image reconstruction and analysis software. The scanner outputs were compared against the input STOs. First proof-of-principle was discussed and supported by correlation between scanner outputs and the input STO. The work makes no claim that its examples are valid QA methods. It concludes by proposing a new industrial standard for QA without the FC.

ACR Accreditation of a Novel Linac-Based kV-CBCT System on a High-Speed Ring-Gantry

An advanced kV-CBCT imaging system mounted on a high-speed ring-gantry Linac has recently been introduced, offering improved imaging hardware and reconstruction software to produce high quality CBCT images usable for treatment planning. Imaging performance of the system was assessed using the American College of Radiology (ACR) accreditation designed for diagnostic CT systems, additionally comparing its results to pre-existing diagnostic CT and Linac-based CBCT systems. All imaging protocols on the novel imaging system were scanned with the ACR head phantom and evaluated using ACR recommended testing and passing criteria. ACR image quality parameters include contrast-to-noise ratio (CNR), spatial resolution, HU accuracy, image scaling, and HU uniformity. CNR ≥1.0 for adult head and body, ≥0.7 for pediatric head, and ≥0.4 for pediatric body imaging protocols pass ACR criteria. Spatial resolution ≥6 line-pairs/cm for head and ≥5 line-pairs/cm for body protocols pass ACR criteria. HU accuracy passing criteria includes acrylic (110 to 135 HU), air (-1005 to -970 HU), bone (850 to 970 HU), polyethylene (-107 to -84 HU), and water (-7 to 7 HU). Image scaling measurements with errors ≤5% and HU uniformity maximum differences ≤5 HU pass ACR criteria. For machine cross-comparisons, adult Head and Pelvis imaging protocols were acquired on an existing diagnostic CT and 2 Linac-based CBCT systems (1 traditional C-arm and 1 ring-gantry) and analyzed with the same ACR methodology and passing criteria, with passing rates compared. On the novel imaging system, all standard patient size imaging protocols using 125 kVp (Head, H&N, Thorax, Thorax Slow, Breast, Abdomen, Pelvis, Pediatric Head, and Pediatric Abdomen) passed all ACR criteria; while 2 larger patient focused imaging protocols using 140 kVp (Abdomen Large and Pelvis Large) produced minor deviations on HU uniformity (maximum differences of 5 - 7 HU) but passed all other ACR criteria. The novel system matched passing rates of a diagnostic CT simulator, and outperformed pre-existing Linac based CBCT imaging systems. This newly developed advanced imaging system produces high quality images, meeting diagnostic CT ACR recommendations and far surpassing the CBCT image quality currently available on pre-existing Linacs.

Magnetic resonance imaging in granular flows: An overview of recent advances

In this review we explore the recent developments in the use of Magnetic Resonance Imaging (MRI) for studying granular flows. While MRI has been a valuable tool in this field for the past 40 years, recent advances in imaging hardware, reconstruction software and particles synthesis have significantly enhanced its capabilities. This article provides an overview of the current challenges of MRI and progress in the field of granular media, and gives a perspective of the possible future developments in the field.

Optimization of Revision Hip Arthroplasty Workflow by Means of Detailed Pre-Surgical Planning Using Computed Tomography Data, Open-Source Software and Three-Dimensional-Printed Models.

In revision hip arthroplasty (RHA), establishing the center of rotation (COR) can be technically challenging due to the acetabular bone destruction that is usually present, particularly in severe cases such as Paprosky type II and III defects. The aim of this study was to demonstrate the use of open-source medical image reconstruction software and low-cost 3D anatomical models in pre-surgical planning of RHA. A total of 10 patients, underwent RHA and were included in the study. Computed tomography (CT) scans were performed for all cases, before surgery and approximately 1 week after the procedure. The reconstruction of CT data, 3D virtual planning of the COR and positioning of acetabular cups, including their inclination and anteversion angles, was carried out using the free open source software platform 3D Slicer. In addition, anatomical models of the pelvis were built on a desktop 3D printer from polylactic acid (PLA). Preoperative and postoperative reconstructed imaging data were compared for each patient, and the position of the acetabular cups as well as the COR were evaluated for each case. Analysis of the pre- and post-op center of rotation position data indicated statistically insignificant differences for the location of the COR on the X-axis (1.5 mm, t = 0.5741, p = 0.5868) with a fairly strong correlation of the results (r = -0.672, p = 0.0982), whilst for the location of the COR in the Y and Z-axes, there was statistical dependence (Y axis, 4.7 mm, t = 3.168 and p = 0.0194; Z axis, 1.9 mm, t = 1.887 and p = 0.1081). A strong correlation for both axes was also observed (Y and Z) (Y-axis, r = 0.9438 and p = 0.0014; Z-axis, r = 0.8829 and p = 0.0084). Analysis of inclination angle values showed a statistically insignificant difference between mean values (3.9 degrees, t = 1.111, p = 0.3092) and a moderate correlation was found between mean values (r = -0.4042, p = 0.3685). Analysis of the anteversion angle showed a statistically insignificant difference between mean values (1.9 degrees, t = 0.8671, p = 0.4192), while a moderate correlation between mean values was found (r = -0.4782, p = 0.2777). Three-dimensional reconstruction software, together with low-cost anatomical models, are very effective tools for pre-surgical planning, which have great potential use in orthopedic surgery, particularly RHA. In up and in- and up and out-type defects, it is essential to establish a new COR and to identify three support points within the revision acetabulum in order to correctly position acetabular cups.

Computational fluid dynamics validated by micro particle image velocimetry to estimate the risk of hemolysis in arteries with atherosclerotic lesions

We aimed to verify the relationship between blood vessel shape and hemolysis risk by using a blood rheological model that reflects the physiological processes related to blood flow. Blood rheology depends on many factors including the red blood cell concentration and local shear stress, which affect the hemolysis process. We introduced a rheology model suitable for modeling hemolysis flows observed in arteries with atherosclerotic lesions in vivo based on the population balance. The model predicts the concentration of single red blood cells and the concentration and size of red blood cell agglomerates, which affect blood rheology and hemolysis. Atherosclerotic lesion geometries were obtained based on image reconstructions from tomographic projections. Computational fluid dynamics (CFD) simulation results were compared with particle image velocimetry measurements of the geometries printed with a 3D printer. Based on the CFD simulation data, a correlation function was established by combining the essential parameters of vessel shape and flow rate with the maximum shear stress, which governs the hemolysis. The chemical engineering methodology was successfully applied to the analysis of biological systems. In future, the model can be implemented in image reconstruction software using tomographic projections to quickly analyze hemolysis risk in medical practice.

Investigation and optimization of PET-guided SPECT reconstructions for improved radionuclide therapy dosimetry estimates

AimsTo investigate and optimize the SPECTRE (Single Photon Emission Computed Theranostic REconstruction) reconstruction approach, using the hybrid kernelized expectation maximization (HKEM) algorithm implemented in the software for tomographic image reconstruction (STIR) software library, and to demonstrate the feasibility of performing algorithm exploration and optimization in 2D. Optimal SPECTRE parameters were investigated for the purpose of improving SPECT-based radionuclide therapy (RNT) dosimetry estimates.MethodsUsing the NEMA IEC body phantom as the test object, SPECT data were simulated to model an early and late imaging time point following a typical therapeutic dose of 8 GBq of 177Lu. A theranostic 68Ga PET-prior was simulated for the SPECTRE reconstructions. The HKEM algorithm parameter space was investigated for SPECT-unique and PET-SPECT mutual features to characterize optimal SPECTRE parameters for the simulated data. Mean and maximum bias, coefficient of variation (COV %), recovery, SNR and root-mean-square error (RMSE) were used to facilitate comparisons between SPECTRE reconstructions and OSEM reconstructions with resolution modelling (OSEM_RM). 2D reconstructions were compared to those performed in 3D in order to evaluate the utility of accelerated algorithm optimization in 2D. Segmentation accuracy was evaluated using a 42% fixed threshold (FT) on the 3D reconstructed data.ResultsSPECTRE parameters that demonstrated improved image quality and quantitative accuracy were determined through investigation of the HKEM algorithm parameter space. OSEM_RM and SPECTRE reconstructions performed in 2D & 3D were qualitatively and quantitatively similar, with SPECTRE showing an average reduction in background COV % by a factor of 2.7 and 3.3 for the 2D case and 3D case respectively. The 42% FT analysis produced an average % volume difference from ground truth of 158% and 26%, for the OSEM_RM and SPECTRE reconstructions, respectively.ConclusionsThe SPECTRE reconstruction approach demonstrates significant potential for improved SPECT image quality, leading to more accurate RNT dosimetry estimates when conventional segmentation methods are used. Exploration and optimization of SPECTRE benefited from both fast reconstruction times afforded by first considering the 2D case. This is the first in-depth exploration of the SPECTRE reconstruction approach, and as such, it reveals several insights for reconstructing SPECT data using PET side-information.

Advances in Optical/Infrared Interferometry

After decades of fast-paced technical advances, optical/infrared (O/IR) interferometry has seen a revolution in recent years: ▪ The GRAVITY instrument at the Very Large Telescope Interferometer (VLTI) with four 8-m telescopes reaches thousand-times-fainter objects than possible with earlier interferometers, and the Center for High Angular Resolution Astronomy array (CHARA) routinely offers up to 330-m baselines and aperture synthesis with six 1-m telescopes. ▪ The observed objects are fainter than 19 mag, the images have submilliarcsecond resolution, and the astrometry reaches microarcsecond precision. ▪ This led to breakthrough results on the Galactic Center, exoplanets, active galactic nuclei, young stellar objects, and stellar physics. Following a primer in interferometry, we summarize the advances that led to the performance boost of modern interferometers: ▪ Single-mode beam combiners now combine up to six telescopes, and image reconstruction software has advanced over earlier developments for radio interferometry. ▪ With a combination of large telescopes, adaptive optics (AO), fringe tracking, and especially dual-beam interferometry, GRAVITY has boosted the sensitivity by many orders of magnitude. Another order-of-magnitude improvement will come from laser guide star AO. In combination with large separation fringe tracking, O/IR interferometry will then provide complete sky coverage for observations in the Galactic plane and substantial coverage for extragalactic targets.

Calibration and Evaluation of a Motion Measurement System for PET Imaging Studies

Positron Emission Tomography (PET) enables functional imaging of deep brain structures, but the bulk and weight of current systems preclude their use during many natural human activities, such as locomotion. The proposed long-term solution is to construct a robotic system that can support an imaging system surrounding the subject’s head, and then move the system to accommodate natural motion. This requires a system to measure the motion of the head with respect to the imaging ring, for use by both the robotic system and the image reconstruction software. We report here the design, calibration, and experimental evaluation of a parallel string encoder mechanism for sensing this motion. Our results indicate that with kinematic calibration, the measurement system can achieve accuracy within 0.5[Formula: see text]mm, especially for small motions.

Central Pericystectomy for Hydatid Cyst Treatment

BackgroundCompared to open resection for hepatic hydatid cysts, a laparoscopic approach may combine the benefit of reduced morbidity with complete cyst removal. Nonetheless, intraoperative cyst rupture during a laparoscopic approach due to reduced tactile feedback is a valid concern.1-3 Today, the laparoscopic experience remains limited even in high incidence regions.4 Here, a structured approach to laparoscopic pericystectomy is demonstrated. PatientA 37-year-old male from Uruguay presents with worsening abdominal pain, nausea, and vomiting. A 4-phase liver CT shows a large complex liver cyst (8.8 × 8.2 × 11.3 cm), encompassing the left hepatic lobe while abutting right hepatic vein (RHV), anterior fissure vein (AFV) and inferior vena cava (IVC). Further, the cyst causes mass effect on the hepatic vein vasculature. CT appearance is consistent with a large hydatid cyst with distorted hepatic anatomy resulting in compensatory hypertrophy of segments II, VI and VII. Appropriate institutional review board (IRB) and inform consent was obtained. TechniqueFollowing neoadjuvant albendazole for 4 weeks to minimize any effects in case of inadvertent cyst spillage, the patient tested negative for echinococcal antibody. For surgical planning, the patient’s anatomy was modeled to optimize the understanding of the complex spatial relationship between cyst, portal pedicle and hepatic veins. Further, port sites were preoperatively modelled to optimize port placement in the context of the altered anatomy from compensatory hepatic hypertrophy. During surgery, with the patient in a modified French position, the liver was completely mobilized. Then, a parenchymal transection plane was developed guided by RHV, AFV and IVC, while biliary radicals entering directly into the cyst were controlled individually. The complex transection plane resulted in preservation of the unaffected liver segments I, II, VI and VII. ConclusionThe multimodal approach demonstrated here included pretreatment with albendazole followed by safe laparoscopic pericystectomy. In the preoperative setting, albendazole can reduce the risk of recurrence if spillage occurs during surgery. In inoperable patients, it has been previously shown to be an effective monotherapy for small (< 5 cm) CE1 and CE3a cysts.5 For preoperative planning, an automated image reconstruction software (Fujifilm Synapse 3D) is used. The software creates a 3D model of the liver segmentation and vessels from contrast-enhanced CT and MR images. In addition to modelling the liver, port placement in relation to the liver is being simulated prior to surgery to optimize port placement at the time of surgery. During the case, the parenchymal transection is guided by RHV, AFV and IVC. The common postoperative complication of persistent biliary leakage was avoided by controlling each biliary radicals entering the cyst from the liver parenchyma. Biliary leaks are a common complication and have been positively correlated with the cyst diameter (~ 79% of cysts with diameter of 7.5 cm or greater have cysto-biliary fistula).6 In this context, indocyanine green may help to identify relevant biliary radicals entering the cyst or aid in recognizing bile leaks. If the stepwise approach described here is followed, minimally invasive pericystectomy represents a safe alternative to open surgery, harnessing the advantages of minimal risk of recurrence due to complete cyst removal and low morbidity.

Technological advancements in cancer diagnostics: Improvements and limitations.

Cancer is characterized by the rampant proliferation, growth, and infiltration of malignantly transformed cancer cells past their normal boundaries into adjacent tissues. It is the leading cause of death worldwide, responsible for approximately 19.3 million new diagnoses and 10 million deaths globally in 2020. In the United States alone, the estimated number of new diagnoses and deaths is 1.9 million and 609 360, respectively. Implementation of currently existing cancer diagnostic techniques such as positron emission tomography (PET), X-ray computed tomography (CT), and magnetic resonance spectroscopy (MRS), and molecular diagnostic techniques, have enabled early detection rates and are instrumental not only for the therapeutic management of cancer patients, but also for early detection of the cancer itself. The effectiveness of these cancer screening programs are heavily dependent on the rate of accurate precursor lesion identification; an increased rate of identification allows for earlier onset treatment, thus decreasing the incidence of invasive cancer in the long-term, and improving the overall prognosis. Although these diagnostic techniques are advantageous due to lack of invasiveness and easier accessibility within the clinical setting, several limitations such as optimal target definition, high signal to background ratio and associated artifacts hinder the accurate diagnosis of specific types of deep-seated tumors, besides associated high cost. In this review we discuss various imaging, molecular, and low-cost diagnostic tools and related technological advancements, to provide a better understanding of cancer diagnostics, unraveling new opportunities for effective management of cancer, particularly in low- and middle-income countries (LMICs). Herein we discuss various technological advancements that are being utilized to construct an assortment of new diagnostic techniques that incorporate hardware, image reconstruction software, imaging devices, biomarkers, and even artificial intelligence algorithms, thereby providing a reliable diagnosis and analysis of the tumor. Also, we provide a brief account of alternative low cost-effective cancer therapy devices (CryoPop®, LumaGEM®, MarginProbe®) and picture archiving and communication systems (PACS), emphasizing the need for multi-disciplinary collaboration among radiologists, pathologists, and other involved specialties for improving cancer diagnostics. Revolutionary technological advancements in cancer imaging and molecular biology techniques are indispensable for the accurate diagnosis and prognosis of cancer.

Thoracic cavity remodeling and pulmonary function change after chest wall resection.

Chest wall resection (CWR) is an essential procedure for treating malignancies and infectious conditions of the chest wall. However, there are few studies on the pulmonary function and changes in thoracic cavity volume (TCV) related to CWR. This study aims to investigate the effects of CWR on long-term changes in TCV and pulmonary function. Data of patients who underwent CWR between 2001 and 2021 were retrospectively reviewed. Patients who underwent single rib or lung resection rather than wedge resection were excluded. TCV (liter) was defined as the sum of the right and left TCVs (RCV and LCV) and was measured using computed tomography image reconstruction software. Changes in pulmonary function and TCV 1 year postoperatively were analyzed. A total of 45 patients were included. The number of resected ribs was 2 in 16 (35.6%) and ≥3 in 29 (64.4%) patients. Thirty patients underwent reconstruction. Long-term post-CWR decreased in forced vital capacity (FVC) (-7.9%, P=0.004) and forced expiratory volume in 1 second (FEV1) (-7.0%, P=0.002) were significant. There was no significant decrease in FEV1/FVC ratio (-3.0%, P=0.06), diffusing capacity of the lung for carbon monoxide (DLCO) (-5.9%, P=0.18) and TCV (-3.1%, P=0.10). There was no correlation between changes in TCV and decreases in FVC (r=0.12, P=0.56) or FEV1 (r=0.15, P=0.45). After right-side CWR (n=27), RCV (-7.8%, P=0.01) decreased significantly, whereas LCV (+2.1%, P=0.58) did not. The left-side CWR exhibited an identical pattern. (LCV: -8.5%, P=0.004; RCV: +1.3%, P=0.85). In the ≥3 rib-resection group, FVC (-9.5%, P=0.02), FEV1 (-7.9%, P=0.02) and TCV (-6.4%, P=0.04) decreased significantly. No significant changes were noted in the 2 rib-resection group. There were no significant differences in the changes in pulmonary function nor TCV between the reconstruction and no-reconstruction groups. The long-term decrease in pulmonary function after CWR was significant, especially after ≥3-rib resection.

Kitchen-based light tomography - a DIY toolkit for advancing tomography - by and for the tomography community

We present a recipe for building a portable DIY toolkit, entitled Kitchen-Based Light Tomography (KBLT) for performing tomography using visible light with low-cost and easily accessible components. We also present different use cases to mimic different challenges in tomography, such as imaging time evolving samples. All the software for motor controls, image acquisition, image reconstruction and analysis is open-sourced and available online. The fast acquisition of KBLT datasets permits 4D scanning (3D plus time), also in combination with so-called sample environments, which can support the advancement of improved image reconstruction algorithms. We believe this ‘Do it yourself’ (DIY) toolkit will be useful to tomography users, beamline scientists and computational researchers, and the tomography community in general.

The intersegmental pulmonary vein is not always located on the intersegmental plane of the lung: Evaluation with 3-dimensional volume-rendering image reconstruction.

To clarify whether intersegmental pulmonary veins are always located on the intersegmental plane and determine the division from which blood flows into them. We analyzed representative intersegmental veins located between the upper/lingular and superior/basal division of the lungs using preoperative chest computed tomography (CT) DICOM data from 22 patients who underwent lobectomy or segmentectomy during 2020. The location and blood flow of V3a+b andV6b+c were assessed using REVORAS (Ziosoft), a novel volume-rendering 3-dimensional (3D) image reconstruction software dedicated to lung segmentectomy. The V3a+b was in the upper division and on the intersegmental plane between the upper and lingular divisions of the left lung in 11 patients (50%) each. A main root of V3a+b was not found in the lingular division, but some peripheral flow in the V3a+b was derived from it in 14 patients (64%). The V6b+c was found in the superior division of the right lower lobe in 13 patients (59%) and the left lower lobe in 10 patients (45%), and on the intersegmental plane between the superior and basal division of the right lower lobe in 6 patients (27%) and the left lower lobe in 10 patients (45%). A main root of V6b+c was imperceptible in the basal division. Some peripheral blood flow was derived from the basal division in 6 patients (27%) with V6b+c veins located in the right lower lobe and in 8 patients (36%) with V6b+c veins located in the left lower lobe. Precise evaluation of intersegmental veins using preoperative volume-rendering 3D reconstructed CT images provides useful anatomic information for separating intersegmental pulmonary parenchyma.

Impact of transcatheter tricuspid valve replacement for tricuspid regurgitation on hepatic, cardiac, and venous structure

BackgroundPatients with long-term tricuspid regurgitation (TR) are mostly accompanied by hepatic, cardiac, and venous remodeling. Transcatheter tricuspid valve replacement (TTVR) device has emerged as a promising alternative to open-heart surgery for TR patients. No study has assessed the impact of TTVR on hepatic, cardiac, and venous remodeling. MethodsTwenty-two patients with TR enrolled in this study underwent TTVR between October 2020 and January 2021. Liver, heart, and veins were reconstructed by three-dimensional computed tomography reconstruction software at baseline and 6 months follow-up. ResultsTwenty-two patients were enrolled in this study. The mean age was 64.8 ± 8.2 years, and all patients had severe or greater TR with multiple comorbidities. The left hepatic lobe volume decreased from 518.8 ± 171.9 ml to 470.4 ± 179.6 ml at 6 months during follow-up (p = 0.049). Evidence of a decrease in three hepatic veins parameters and splenic vein parameters was noted from baseline to 6 months. And a significant decrease in right atrial volume (317.5 ml [interquartile range: 216.1 to 497.3 ml] vs. 266.7 ml [interquartile range: 178.7 to 480.7 ml]; p = 0.003) were observed in the study. ConclusionsSix-month outcomes show that TR elimination by LuX-Valve is associated with the reverse remodeling of liver, heart, and veins. Accordingly, LuX-Valve is a promising alternative for patients presenting with severe TR.

Human cortical amygdala dendrites and spines morphology under open-source three-dimensional reconstruction procedures.

Visualizing nerve cells has been fundamental for the systematic description of brain structure and function in humans and other species. Different approaches aimed to unravel the morphological features of neuron types and diversity. The inherent complexity of the human nervous tissue and the need for proper histological processing have made studying human dendrites and spines challenging in postmortem samples. In this study, we used Golgi data and open-source software for 3D image reconstruction of human neurons from the cortical amygdaloid nucleus to show different dendrites and pleomorphic spines at different angles. Procedures required minimal equipment and generated high-quality images for differently shaped cells. We used the "single-section" Golgi method adapted for the human brain to engender 3D reconstructed images of the neuronal cell body and the dendritic ramification by adopting a neuronal tracing procedure. In addition, we elaborated 3D reconstructions to visualize heterogeneous dendritic spines using a supervised machine learning-based algorithm for image segmentation. These tools provided an additional upgrade and enhanced visual display of information related to the spatial orientation of dendritic branches and for dendritic spines of varied sizes and shapes in these human subcortical neurons. This same approach can be adapted for other techniques, areas of the central or peripheral nervous system, and comparative analysis between species.

A Rapid, Low-Cost, and High-Precision Multifrequency Electrical Impedance Tomography Data Acquisition System for Plant Phenotyping

Plant phenotyping plays an important role for the thorough assessment of plant traits such as growth, development, and physiological processes with the target of achieving higher crop yields by the proper crop management. The assessment can be done by utilizing two- and three-dimensional image reconstructions of the inhomogeneities. The quality of the reconstructed image is required to maintain a high accuracy and a good resolution, and it is desirable to reconstruct the images with the lowest possible noise. In this work, an electrical impedance tomography (EIT) data acquisition system is developed for the reconstruction and evaluation of the inhomogeneities by utilizing a non-destructive method. A high-precision EIT system is developed by designing an electrode array sensor using a cylindrical domain for the measurements in different planes. Different edible plant slices along with multiple plant roots are taken in the EIT domain to assess and calibrate the system, and their reconstructed results are evaluated by utilizing an impedance imaging technique. A non-invasive imaging is carried out in multiple frequencies by utilizing a difference method of reconstruction. The performance and accuracy of the EIT system are evaluated by measuring impedances between 1 and 100 kHz using a low-cost and rapid electrical impedance spectroscopy (EIS) tool connected to the sensor. A finite element method (FEM) modeling is utilized for image reconstruction, which is carried out using electrical impedance and diffuse optical tomography reconstruction software (EIDORS). The reconstruction is made successfully with the optimized results obtained using Gauss–Newton (GN) algorithms.

An In Situ Electrical Impedance Tomography Sensor System for Biomass Estimation of Tap Roots.

Root biomass is one of the most relevant root parameters for studies of plant response to environmental change. In this work, a dynamic and adjustable electrode array sensor system is designed for developing a cost-effective, high-speed data acquisition system based on electrical impedance tomography (EIT). The developed EIT system is found to be suitable for in situ measurements and capable of monitoring the changes in root growth and development with three-dimensional imaging by measuring impedances in multiple frequencies with the help of an EIT sensor. The designed EIT sensor system is assessed and calibrated by the inhomogeneities in both water and soil media. The impedances are measured for multiple tap roots using an electrical impedance spectroscopy (EIS) tool connected to the sensor at frequencies ranging from 1 kHz to 100 kHz. The changes in conductivity are calculated by obtaining the boundary voltages from the measured impedances for a given stimulation current. A non-invasive imaging method is utilized, and the spectral changes are observed accordingly to evaluate the growth of the roots. A further root analysis helps us estimate the root biomass non-destructively in real-time. The root size (such as, weight, length) is correlated with the measured impedances. A regression analysis is performed using the least square method, and more than 97% correlation is found for the biomass estimation of carrot roots with an RMSE of 4.516. The obtained models are later validated using a new and separate set of carrot root samples and the accuracy of the predicted models is found to be 93% or above. A complete electrode model is utilized, and the reconstruction analysis is performed and optimized by utilizing the impedance imaging technique in difference method. The tomography of the root is reconstructed with finite element method (FEM) modeling considering one-step Gauss–Newton (GN) algorithm which is carried out using an open source software known as electrical impedance and diffuse optical tomography reconstruction software (EIDORS).

Development and commissioning of a compact Cosmic Ray Muon imaging prototype

Due to the muon tomography’s capability of imaging high Z materials, some potential applications have been reported on inspecting smuggled nuclear materials in customs. A compact Cosmic Ray Muons (CRM) imaging prototype, Lanzhou University Muon Imaging System (LUMIS), is comprehensively introduced in this paper including the structure design, assembly, data acquisition and analysis, detector performance test, and material imaging commissioning etc. Cast triangular prism plastic scintillators (PS) were coupled with Si-PMs for sensitive detector components in system. LUMIS’s experimental results show that the detection efficiency of an individual detector layer is about 98%, the position resolution for vertical incident muons is 2.5 mm and the angle resolution is 8.73 mrad given a separation distance of 40.5 cm. Moreover, the image reconstruction software was developed based on the Point of Closest Approach (PoCA) to detect lead bricks as our target. The reconstructed images indicate that the profile of the lead bricks in the image is highly consistent with the target. Subsequently, the capability of LUMIS to distinguish different materials, such as Pb, Cu, Fe, and Al, was investigated as well. The lower limit of response time for rapidly alarming high-Z materials is also given and discussed. The successful development and commissioning of the LUMIS prototype have provided a new solution option in technology and craftsmanship for developing compact CRM imaging systems that can be used in many applications.

Influences on PET Quantification and Interpretation.

Various factors have been identified that influence quantitative accuracy and image interpretation in positron emission tomography (PET). Through the continuous introduction of new PET technology—both imaging hardware and reconstruction software—into clinical care, we now find ourselves in a transition period in which traditional and new technologies coexist. The effects on the clinical value of PET imaging and its interpretation in routine clinical practice require careful reevaluation. In this review, we provide a comprehensive summary of important factors influencing quantification and interpretation with a focus on recent developments in PET technology. Finally, we discuss the relationship between quantitative accuracy and subjective image interpretation.