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Study on joint de-noising method of ECG signals with improved CEEMDAN-wavelet thresholding and singular spectrum analysis

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JOURNAL OF INSTRUMENTATION 2025年第1期20卷

作者： Ge, Liang Ma, Yuhong Xiao, Xiaoting Cheng, Jixiang Li, Zhidan Qin, Wang Southwest Petr Univ Sch Mech & Elect Engn Chengdu 610500 Peoples R China Southwest Petr Univ Sch Elect Engn & Informat Chengdu 610500 Peoples R China

The electrocardiogram (ECG) signal is often contaminated by various noises during acquisition and transmission, and the denoising effect directly affects the diagnosis of heart diseases. To improve the denoising effect, this paper proposes an improved Complete Ensemble Empirical Mode Decomposition (CEEMDAN)-wavelet thresholding and singular spectrum analysis (SSA) denoising method. First, the noise-dominated high-frequency intrinsic mode function (IMF) identified using CEEMDAN;second, it is denoised to reduce high-frequency noise by the improved wavelet thresholding technique;and then, SSA is used to remove baseline wander (BW);finally, to verify the effectiveness of this denoising method, the root mean square error (RMSE) and signal-to-noise ratio (SNR) are used as the evaluation criteria for the denoising effect and the standard MIT-BIH ECG noise database signals are used for verification. The validation results show that compared the existing ECG denoising methods, the denoising method improves the SNR by 39% 55% reduces the RMSE by 18% 42%. The method can be used as an effective tool for ECG signal denoising and provide a better basis for diagnosis in computerized automated medical systems.

关键词： Data processing methods medical-image reconstruction methods and algorithms, computer-aided diagnosis Bioinstrumentation

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Picosecond timing performances of the FERS time unit

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JOURNAL OF INSTRUMENTATION 2025年第1期20卷

作者： Giordano, F. Colombini, L. Doroud, K. Maggio, C. Mati, A. Ninci, D. Picchi, A. Tintori, C. Venturini, Y. Williams, C. Williams, T. CAEN Spa Via Vetraia 11 Viareggio LU Italy Picotech SAS 90 Rue Henri Fabre St Genis Pouilly France

Next-generation high-energy physics experiments will employ high-granularity detectors with thousands of readout channels, necessitating the use of low-power, compact ASICs. The CAEN FrontEnd Readout System (FERS) 5200 integrates these ASICs within small, synchronizable, and distributable systems featuring both Front and Back Ends. The A5203 FERS module incorporates the recently released CERN picoTDC ASIC, enabling high-resolution timing measurements for Time of Arrival (ToA) and Time over Threshold (ToT). In this work, we analyze the performance of the A5203 unit, which has a 3.125 ps least significant bit (LSB), delivering ToA measurements with an RMS resolution of approximately 7 ps for signals of fixed amplitude, and approximately 20 ps RMS for input signals with variable amplitude over a 50 dB dynamic range over a single board. The amplitude-dependent walk effect is corrected using ToT, which, in addition to walk correction, is also utilised for signal amplitude reconstruction and background reduction. The A5203 has been successfully applied across various experimental and industrial contexts. In the concluding section of this paper, we will discuss its application within the ProVision project: a PET scanner specialised in imaging aggressive prostate cancer at an early-stage.

关键词： Front-end electronics for detector readout Modular electronics medical-image reconstruction methods and algorithms, computer-aided diagnosis

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Synthesising two-dimensional mammographic images using compressed sensing-reconstructed digital breast tomosynthesis images

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JOURNAL OF INSTRUMENTATION 2024年第8期19卷 P08012页

作者： Han, Seohee Yang, Hyesun Xu, Wenting Seo, Changwoo Cho, Hyosung Cha, Bo Kyung Yonsei Univ Dept Radiat Convergence Engn Wonju South Korea Korea Electrotechnol Res Inst Precis Med Device Res Ctr Ansan South Korea

This study presents a method synthesizing a two-dimensional (2D) mammographic image of reasonable quality directly from a 3D digital breast tomosynthesis (DBT) image, reconstructed using an advanced compressed sensing (CS)-based algorithm. This approach aims to reduce the radiation dose required for complementary imaging technologies of digital mammography (DM) and DBT, eliminating the need for additional DM examinations. The method involves three main steps: projection data acquisition from a DBT system, CS-based DBT reconstruction, and synthesis of a 2D mammographic image from the reconstructed DBT image. To verify the efficacy of the proposed method, we conducted both a simulation and an experiment on a numerical breast and commercially available BR3D phantoms, respectively, prior to practical implementation in real-world DBT systems. Our simulation and experimental results indicated that the CS-based algorithm yielded markedly improved DBT reconstruction quality, preserving superior image homogeneity, better edge contour and sharpening, and fewer image artifacts. The measured contrast-to-noise ratio and structural similarity values of the CS-reconstructed DBT images were 10.31 and 0.78, respectively, which were approximately 2.2 and 3.1 times larger, respectively, than those of the filtered-backprojectionreconstructed DBT images in the simulation. The quality of the synthetic mammographic images using the CS-reconstructed DBT images was similar to that of conventional mammographic images obtained using a full dose, indicating the efficacy of the proposed method. Consequently, we successfully reconstructed DBT images of substantially high quality using the CS-based algorithm and synthesised 2D mammographic images of reasonable quality, potentially reducing the radiation dose to patients in the complementary imaging technologies of DM and DBT.

关键词： Data processing methods medical-image reconstruction methods and algorithms, computer-aided diagnosis X-ray mammography and scinto- and MRI-mammography

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A comparative study of crystal geometry, material, and reconstruction algorithms on MicroPET scanner performance

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JOURNAL OF INSTRUMENTATION 2024年第8期19卷 P08028页

作者： Sadremomtaz, Alireza Taherparvar, Payvand Saber, Mohaddeseh Univ Guilan Fac Sci Dept Phys Namjoo AvePostal Code ***POB Rasht 416351914 Guilan Iran

Small-animal PET, also known as microPET, has been developed to enhance image quality by improving spatial resolution and sensitivity due to its smaller ring and crystal size. However, the reduction of crystal size and the presence of gaps between cuboidal crystals could reduce sensitivity. MicroPET with tapered arrays has been developed to simultaneously improve sensitivity and spatial resolution. This study compared the performance of 14 x 14 and 28 x 28 array microPETs using LSO and CZT crystal materials. The impact of crystal design and reconstruction algorithms on image quality and performance parameters was investigated, using GATE Monte Carlo simulation toolkit. The findings showed that sensitivity increased with crystal thickness, particularly in LSO. The 14 x 14 arrays consistently exhibited higher sensitivity, while the 28 x 28 arrays had superior spatial resolution. NECR values increased with crystal thickness, with LSO outperforming CZT. Scatter and random fractions were low. Different reconstruction algorithms had negligible effects on FWHM and CNR but influenced SNR, with the COSEM algorithm achieving significantly reduced noise. The small size of crystals and tapered arrays contributed to improved sensitivity and spatial resolution. However, there was a trade-off between sensitivity and spatial resolution. LSO crystals showed better performance, but the choice between array sizes depended on specific imaging requirements. This study provides insights into optimizing microPET design for enhanced imaging capabilities.

关键词： Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided diagnosis Models and simulations

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MAIR-Net: a sparse-view CT reconstruction network based on a combination of mixed attention and iterative optimization learning

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JOURNAL OF INSTRUMENTATION 2024年第8期19卷 P08029页

作者： Guo, Tong Liu, Yi Zhang, Pengcheng Liu, Yu Gui, Zhiguo North Univ China Sch Informat & Commun Engn Taiyuan Peoples R China

Sparse-view computed tomography (CT) is one of the main means to reduce radiation risk. When the projection data is highly undersampled, the reconstructed CT image may suffer from serious stripe artifacts and structural information loss. In this paper, we propose a sparse-view CT reconstruction network architecture combining mixed attention (MA) and an iterative reconstruction strategy, called MAIR-Net. Firstly, the approach expands the proximal gradient descent into the neural network and uses an initial value enhancement module between the gradient descent module and the proximal mapping module. The aim is to enhance the flow of detailed information between different layers, fully retain image details, and improve the network convergence speed. Secondly, the mixed attention module (MAM) is introduced into the reconstruction process as a regularization term. It adaptively fuses local and non-local features of the image, which are used to reduce the over-smoothing of the reconstructed image and fully retain the details of the reconstructed image, respectively. Experimental results showed that the proposed method can better retain the details of the reconstructed image and improve the quality of the reconstructed image while inhibiting the sparse angle artifacts of the CT reconstructed image.

关键词： computerized Tomography (CT) and Computed Radiography (CR) image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided diagnosis

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MLEM-based image reconstruction algorithm for fast neutron scattering imaging

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JOURNAL OF INSTRUMENTATION 2024年第12期19卷

作者： Shin, Jimin Sim, Hayoung Shin, Sunlee Seo, Hee Kim, Soo Mee Jeonbuk Natl Univ Dept Appl Plasma & Quantum Beam Engn 567 Baekje Daero Jeonju Si Jeollabuk Do South Korea Jeonbuk Natl Univ Dept Quantum Syst Engn 567 Baekje Daero Jeonju Si Jeollabuk Do South Korea Korea Inst Ocean Sci & Technol Maritime ICT & Mobil Res Dept 385 Haeyang Ro Busan South Korea

Fast neutrons preserve the initial source information (e.g., position, energy, and time) due to their relatively low probability of interaction with surrounding materials and their straight path. When measuring fast neutrons using scattering reactions, there is no need to slow them down to thermal neutrons. This allows for the obtainment of more accurate information. A neutron scattering imager usually consists of two pixelated scatter detectors. The energy and scattering angle of the neutrons can be determined from the energy of the protons produced by the scattering reaction in the first detector, the time of flight between the two detectors, and the distance between the interaction positions. From these measured quantities, conical surfaces can be drawn, and the source location can be determined roughly from the overlapping of all such surfaces drawn. Maximum Likelihood Expectation Maximization (MLEM) is an iterative statistical algorithm to reconstruct the source distribution from the measured events in the neutron scattering imager. In this study, we developed an MLEM algorithm for fast neutron (<= 20 MeV) scattering image reconstruction using a system matrix with consideration of the scattering cross-section and angular resolution. Then, we compared the resolution of the MLEM images with that of simple back-projection (SBP) images.

关键词： image reconstruction in medical imaging Inspection with neutrons medical-image reconstruction methods and algorithms, computer-aided diagnosis

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Detective quantum efficiency of a double-layered detector for dual-energy x-ray imaging

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JOURNAL OF INSTRUMENTATION 2023年第11期18卷 C11005页

作者： Shin, Hubeom Yoo, Seungjun Oh, Seokwon Lee, Junho Kyung, Ho Pusan Natl Univ Sch Mech Engn Busandaehak Ro 63beon Gil Busan 46241 South Korea Pusan Natl Univ Ctr Adv Med Engn Res Busandaehak Ro 63beon Gil Busan 46241 South Korea

A sandwich-like double-layered detector can perform dual-energy imaging (DEI) using a single x-ray exposure without object motion artifacts. The energy separation between measurements obtained from the front and rear-detector layers can be tuned by introducing an x-ray beam-attenuating material between them. However, the design of the interdetector filter significantly influences dose efficiency by altering the number of x-ray photons reaching the rear-detector layer within the sandwich detector. Since the sandwich detector typically incorporates phosphors of differing thicknesses for its two detector layers, it exhibits a unique spatial resolution characteristic in the reconstructed dual energy (DE) images. To comprehensively assess detector performance in terms of design (filter) and operation (reconstruction), we established a framework that describes the dual-energy detective quantum efficiency (DE-DQE) using linear-systems theory. The developed DE-DQE model was validated through comparison with measurements. The agreement between the modulation-transfer functions was reasonable, and the correspondence between noise-power spectra was excellent. This proposed DE-DQE concept is universally applicable to any linearly operating DE system and holds a significant value in enhancing the performance of sandwich detectors or ensuring their optimal operation.

关键词： medical-image reconstruction methods and algorithms, computer-aided diagnosis Inspection with x-rays X-ray radiography and digital radiography (DR)

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Quantitative comparison of planar coded aperture imaging reconstruction methods

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JOURNAL OF INSTRUMENTATION 2023年第1期18卷 P01006页

作者： MeiBner, T. Rozhkov, V. Hesser, J. Nahm, W. Loew, N. Heidelberg Univ Inst Intelligent Syst Med MIISM Med Fac Mannheim Mannheim Germany Karlsruhe Inst Technol KIT Biomed Engn IBT Karlsruhe Germany Intergovt Org Joint Inst Nucl Res Dubna Russia Heidelberg Univ Ctr Sci Comp IWR Heidelberg Germany Heidelberg Univ Centeral Inst Comp Engn ZITI Heidelberg Germany Heidelberg Univ CZS Heidelberg Ctr Model Based Mannheim Germany

Imaging distributions of radioactive sources plays a substantial role in nuclear medicine as well as in monitoring nuclear waste and its deposit. Coded Aperture Imaging (CAI) has been proposed as an alternative to parallel or pinhole collimators, but requires image reconstruction as an extra step. Multiple reconstruction methods with varying run time and computational complexity have been proposed. Yet, no quantitative comparison between the different reconstruction methods has been carried out so far. This paper focuses on a comparison based on three sets of hot-rod phantom images captured with an experimental gamma-camera consisting of a Tungsten-based MURA mask with a 2 mm thick 256 x 256 pixelated CdTe semiconductor detector coupled to a Timepix((c)) readout circuit. Analytical reconstruction methods, MURA Decoding, Wiener Filter and a convolutional Maximum Likelihood Expectation Maximization (MLEM) algorithm were compared to data-driven Convolutional Encoder-Decoder (CED) approaches. The comparison is based on the contrast-to-noise ratio as it has been previously used to assess reconstruction quality. For the given set-up, MURA Decoding, the most commonly used CAI reconstruction method, provides robust reconstructions despite the assumption of a linear model. For single image reconstruction, however, MLEM performed best of all analytical reconstruction methods, but took on average 45 times longer than MURA Decoding. The fastest reconstruction method is the Wiener Filter with a run time 4.3 times faster compared to MURA Decoding and a mediocre quality. The CED with a specifically tailored training set was able to succeed the most commonly used MURA decoding on average by a factor between 1.37 and 2.60 and an equal run time.

关键词： image reconstruction in medical imaging Search for radioactive and fissile materials Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) medical-image reconstruction methods and algorithms, computer-aided diagnosis

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A study on energy window-based scatter correction methods in 99mTc and 123I imaging

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JOURNAL OF INSTRUMENTATION 2023年第10期18卷 P10009页

作者： Can, M. Karadeniz, O. Kaya, G. Capa Ertay, T. Dokuz Eylul Univ Vocat Sch Hlth Serv Program Nucl Med Tech Izmir Turkiye Dokuz Eylul Univ Inst Hlth Sci Dept Med Phys Izmir Turkiye Dokuz Eylul Univ Fac Sci Dept Phys Izmir Turkiye Dokuz Eylul Univ Fac Med Dept Nucl Med Izmir Turkiye

Tc-99m and I-123 are radionuclides commonly used for diagnostic examination in nuclear medicine. Detection of the scattered photons by the Compton interactions in the photopeak energy window is a factor affecting the image quality. DEW and TEW scatter correction methods are used to improve the image quality degrade by Compton scattered photons. In the study, planar and SPECT images of sphere, rod and cardiac phantom containing different activities were acquired with a gamma camera system. DEW/TEW corrected and uncorrected images for Tc-99m/I-123 were evaluated qualitatively and quantitatively. Both for planar and SPECT images, the DEW and TEW scatter correction methods were found to improve the image quality at varying rates.

关键词： Compton imaging Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA) image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided diagnosis

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The MERLINO project: characterization of LaBr3:Ce detectors for stopping power monitoring in proton therapy

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JOURNAL OF INSTRUMENTATION 2022年第11期17卷 C11013页

作者： Ferrero, V Werner, J. Aglietta, M. Cerello, P. Fiorina, E. Gorgi, A. Vignati, A. Rafecas, M. Pennazio, F. Ist Nazl Fis Nucl Sez Torino Via P Giuria 1 Turin Italy Univ Lubeck Inst Med Engn Ratzeburger Allee 160 Lubeck Germany Ist Nazl Astrofis Osservatorio Astrofis Torino Via Osservatorio 20 Pino Torinese Italy Univ Torino Dipartimento Fis Via P Giuria 1 Turin Italy

The MERLINO project is developing a multi-detector setupwith the goal of evaluating the beam stopping power from Prompt-Gamma-Timing measurements in proton therapy. The detectors are based on the cerium-doped lanthanum bromide crystal, LaBr3:Ce, coupled to photomultiplier tubes. The systemcharacterization is ongoing and the first calibrationmeasurementswith two detectors showed 124 ps sigma and sigma E/E = 3% for the timing and energy resolution, respectively. The measured experimental parameters were then used to carry out a preliminary estimation of the stopping power. Results from the simulation of a 189 MeV proton beam impinging on an homogeneous phantom are presented for the optimisation of the MERLINO detector setup.

关键词： image reconstruction in medical imaging medical-image reconstruction methods and algorithms, computer-aided diagnosis Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc) Models and simulations

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