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Artículos de revistas sobre el tema "XSpectra"

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Publicado: 25 de mayo de 2024

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1

Quercia, J., F. Mele, D. Macera, B. Arcaini, B. Garavelli y G. Bertuccio. "Experimental characterization of a fast X-ray spectroscopic imager module using the ALTAIR P3 ASIC for real-time contaminants detection". Journal of Instrumentation 18, n.º 01 (1 de enero de 2023): C01064. http://dx.doi.org/10.1088/1748-0221/18/01/c01064.

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Abstract X-ray imagers with spectroscopic capabilities and high photon count rates are finding promising applications in industrial real-time inspection systems. In this context, XSpectra® combines a CdTe-based linear energy-resolved photon counting (ERPC) pixel sensor with real-time image processing techniques to detect low and high density contaminants. The detection unit makes use of a new analog read-out ASIC that has been designed by Politecnico di Milano to meet strict application requirements both in energy resolution and achievable photon count rate. A room-temperature low-rate spectroscopic characterization of the system at a peaking time of 60 ns showed an average equivalent noise charge of 259 electrons r.m.s. (2.72 keV FWHM in CdTe) and an average FWHM of the 59.5 keV 241Am line of 3.6 keV, with a 3σ dispersion in noise performance of ±10% over 256 channels. The detection unit was tested in high incoming photon flux conditions by means of an X-ray tube. Minimal spectral distortion due to pile-up events is obtained up to an Incoming Count Rate of 2.5 Mcps/channel, while the maximum counting capability of energy-resolved events is 2.2 Mcps/channel.
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2

Buniatyan, Armen. "Measurement of Feynman-xspectra of photons and neutrons in the very forward direction in deep-inelastic scattering at HERA". EPJ Web of Conferences 99 (2015): 13002. http://dx.doi.org/10.1051/epjconf/20159913002.

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Beck, Michael Thomas, Gregor Rugel, Julia Reinfelder, Torsten Kuwert, Philipp Ritt, Sebastian Kreissel y Tilo Schlittenbauer. "Quantitative Analysis of Multimodal Skeletal SPECT/CT Reconstructions in Diagnosing Medication-related Osteonecrosis of the Jaw". Nuklearmedizin - NuclearMedicine 60, n.º 06 (11 de agosto de 2021): 403–10. http://dx.doi.org/10.1055/a-1525-7621.

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Abstract Aim Our goal was to assess visual and quantitative aspects of multimodal skeletal SPECT/CT reconstructions (recon) in differentiating necrotic and healthy bone of patients with suspected MRONJ. Methods Prior to surgery, 20 patients with suspected MRONJ underwent SPECT/CT of the jaw 3–4 hours after injection of Tc-99m-DPD (622±112.4 MBq). SPECT/CT data were reconstructed using the multimodal xSPECT Bone and xSPECT Quant algorithms as well as the OSEM-algorithm FLASH 3D. For analysis, we divided the jaw into 12 separate regions. Both xSPECT Bone and FLASH 3D datasets were scored on a four-point scale (VIS xSPECT; VIS F3D), based on the intensity of localized tracer uptake. In F3D and xSPECT Quant datasets, local tracer uptake of each region was recorded as semi-quantitative uptake ratio (SQR F3D) or SUVs, respectively. ROC analysis was performed. Postoperative histologic results served as gold standard. Results VIS F3D, VIS xSPECT and SQR F3D did not differ significantly in diagnostic accuracy (VIS xSPECT sensitivity=0.64; specificity=0.89). Of the quantitative parameters, SUVpeak yielded the best interobserver reproducibility. SUVpeak was 9.9±7.1 (95%CI: 7.84–11.95) in MRONJ regions, as opposed 3.6±1.8 (95% CI:3.36–3.88) elsewhere, with a cutpoint of 4.5 (sensitivity=0.83; specificity=0.80). Absolute quantitation significantly surpassed VIS and SQR (p<0.05) in accuracy and interobserver agreement (SUVpeak: κ=0.92; VIS xSPECT: κ=0.61; SQR F3D κ=0.66). Conclusion Absolute quantitation proved significantly more accurate than visual and semi-quantitative assessment in diagnosing MRONJ, with higher interobserver agreement.
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Ignacchiti Lacerda, Marcela, Bruna Costa Rodrigues, Guilherme Ramires de Jesús, Flávia Cunha Dos Santos, Nilson Ramires de Jesús, Roger A. Levy y Evandro Mendes Klumb. "The association between active proliferative lupus nephritis during pregnancy and small for gestational age newborns". Clinical and Experimental Rheumatology 39, n.º 5 (31 de agosto de 2021): 1043–48. http://dx.doi.org/10.55563/clinexprheumatol/xspect.

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Ungania, Sara, Marco D’Arienzo, Sandro Nocentini, Marco D’Andrea, Vicente Bruzzaniti, Raffaella Marconi, Emilio Mezzenga et al. "Optimization of 99mTc-MAA SPECT/CT Imaging for 90Y Radioembolization Using a 3D-Printed Phantom". Applied Sciences 12, n.º 19 (6 de octubre de 2022): 10022. http://dx.doi.org/10.3390/app121910022.

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Radioembolization (RE) with 90Y-microspheres has gained widespread acceptance as a safe and effective technique for treating liver malignancies. Accurate quantification in RE is a key step in treatment planning optimization and is becoming a pressing issue in light of the Directive 2013/59/EURATOM. The aim of this study was to develop a SPECT/CT imaging protocol for quantitative imaging optimization in RE based on cutting edge imaging technology (Symbia IntevoTM system provided with the innovative xSPECT software) and a novel anthropomorphic 3D-printed phantom. In the present study, 99mTc-labeled macroaggregated albumin was used as a surrogate radiopharmaceutical for treatment planning. Gamma camera calibration factors and recovery coefficients were determined performing preliminary SPECT/CT acquisitions of a point source, a cylindrical homogeneous phantom and the NEMA/IEC phantom. Data reconstruction was performed using the built-in xSPECT package, using both the Ordered Subset Expectation–Maximization (OSEM) and the Ordered Subset Conjugated Gradient (OSCG) algorithm. Specific regions of interest (ROIs) were drawn on the MIM 6.1.7 system according to the physical volume. The quantification procedure was validated using the anthropomorphic phantom provided with a fillable liver section and spheres of different diameters (20 mm, 40 mm and a 40 mm spherical shell). The measured activity concentration in all geometries is consistent within 4%, demonstrating that the xSPECT software permit an absolute quantification in anthropomorphic geometry largely within the 10% recommended from the manufacturer. Caution is advised in the presence of spherical objects with a necrotic core, as underestimations in the order of 20% were obtained.
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Christopher, Hoog, Verrecchia-Ramos Emilie, Dejust Sebastien, Lalire Paul, Sezin Ghali, Moubtakir Abdenasser, El Farsaoui Khadija et al. "Implementation of xSPECT, xSPECT bone and Broadquant from literature, clinical survey and innovative phantom study with task-based image quality assessment". Physica Medica 112 (agosto de 2023): 102611. http://dx.doi.org/10.1016/j.ejmp.2023.102611.

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Schnopper, Herbert W. "XSPECT: A Telescope/Spectrometer System on SPECTRUM RÖNTGEN GAMMA". International Astronomical Union Colloquium 115 (1990): 307–17. http://dx.doi.org/10.1017/s0252921100012513.

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AbstractThe SPECTRUM RÖNTGEN-GAMMA mission is being developed by the Babakin Center (BC) together with the Space Research Institute (IKI) of the Academy of Sciences, USSR and is scheduled for launch in 1993. Mission objectives include broad and narrow band imaging spectroscopy over a wide range of energies from the EUV through gamma rays with particular emphasis on the study of extragalactic objects. The Danish Space Research Institute (DSRI) BC and IKI share the responsibility for the preparation of the XSPECT system. Two thin foil telescopes which are conical shell approximations to Wolter 1 geometry, each with an aperture of 60 cm and a focal length of 8 m, are designed to have a half-power width of less than 2 arcmin and will have collecting areas of 1700 and 1200 cm at 2 and 8 keV, respectively. Images and spectra will be recorded with position sensitive proportional counters with good spectral resolution. An objective Bragg crystal panel, placed in front of one of the telescopes, will make high resolution spectroscopic studies (E/ΔE ~103) of point- and extended sources. Other instruments are under consideration.
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Tran-Gia, Johannes y Michael Lassmann. "Characterization of Noise and Resolution for Quantitative 177Lu SPECT/CT with xSPECT Quant". Journal of Nuclear Medicine 60, n.º 1 (5 de julio de 2018): 50–59. http://dx.doi.org/10.2967/jnumed.118.211094.

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Armstrong, Ian S. y Sandra A. Hoffmann. "Activity concentration measurements using a conjugate gradient (Siemens xSPECT) reconstruction algorithm in SPECT/CT". Nuclear Medicine Communications 37, n.º 11 (noviembre de 2016): 1212–17. http://dx.doi.org/10.1097/mnm.0000000000000586.

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Chen, Ew-Jun, Teik Hin Tan y Ming Tsuey Chew. "Superscan: Superiority of xSPECT/CT over OSEM SPECT/CT in bone scans of prostate cancer patients." Radiation Physics and Chemistry 178 (enero de 2021): 108998. http://dx.doi.org/10.1016/j.radphyschem.2020.108998.

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Tristram, M., J. F. Macias-Perez, C. Renault y D. Santos. "XSPECT, estimation of the angular power spectrum by computing cross-power spectra with analytical error bars". Monthly Notices of the Royal Astronomical Society 358, n.º 3 (11 de abril de 2005): 833–42. http://dx.doi.org/10.1111/j.1365-2966.2005.08760.x.

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12

Freije, Rebeca Feixas, Lucia Gracia Martínez-Caro, Raquel Arroyo de la Cruz, Óscar Cordero Ramos, Jose Ceballos Prat, Victoria Carrasco Rubio, Sergio Rodríguez Sancho, Rocio Ramos Membrive y Edgar Fernando Guillén Valderrama. "CO034 - VALORACIÓN CUANTITATIVA DE LA AMILOIDOSIS CARDIACA CON 99MTC-DPD USANDO EL ALGORITMO DE RECONSTRUCCIÓN XSPECT". Revista Española de Medicina Nuclear e Imagen Molecular 42 (mayo de 2023): S176. http://dx.doi.org/10.1016/s2253-654x(23)00300-1.

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Avalon, Juan Carlo, Jacob Fuqua, Seth Deskins, Tyler Miller, Daniel Martin, Gary Marano, James Mills, Christopher Bianco y Yasmin Hamirani. "UTILIZING XSPECT/CT DERIVED STANDARDIZED UPTAKE VALUES TO BETTER QUANTIFY DISEASE BURDEN IN PATIENTS WITH TRANSTHYRETIN-RELATED AMYLOIDOSIS". Journal of the American College of Cardiology 77, n.º 18 (mayo de 2021): 1403. http://dx.doi.org/10.1016/s0735-1097(21)02761-3.

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Armstrong, Ian S. "Spatial dependence of activity concentration recovery for a conjugate gradient (Siemens xSPECT) algorithm using manufacturer-defined reconstruction presets". Nuclear Medicine Communications 40, n.º 3 (marzo de 2019): 287–93. http://dx.doi.org/10.1097/mnm.0000000000000960.

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15

De Laroche, R., P. Robin, J. P. Malhaire, P. Y. Le Roux, S. Querellou, D. Bourhis, P. Y. Salaun y R. Abgral. "Faisabilité d’utilisation de xSPECT-QUANT® en TEMP/TDM osseuse pour l’évaluation thérapeutique des cancers prostatiques métastatiques osseux". Médecine Nucléaire 39, n.º 3 (mayo de 2015): 254. http://dx.doi.org/10.1016/j.mednuc.2015.03.168.

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De Laroche, R., E. Simon, N. Suignard, M. P. Henry, T. Williams, P. Robin, R. Abgral, P. Y. Salaun, F. Dubrana y S. Querellou. "Intérêt de l’analyse quantitative en TEMP/TDM osseuse par xSPECT Quant ® (Siemens) en bilan préchirurgical de gonarthrose". Médecine Nucléaire 41, n.º 3 (mayo de 2017): 168. http://dx.doi.org/10.1016/j.mednuc.2017.02.079.

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17

Ichikawa, Hajime, Noriaki Miyaji, Masahisa Onoguchi, Takayuki Shibutani, Akio Nagaki, Toyohiro Kato y Hideki Shimada. "Feasibility of ultra-high-speed acquisition in xSPECT bone algorithm: a phantom study with advanced bone SPECT-specific phantom". Annals of Nuclear Medicine 36, n.º 2 (3 de noviembre de 2021): 183–90. http://dx.doi.org/10.1007/s12149-021-01689-2.

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18

Delcroix, O., P. Robin, M. Gouillou, A. Le Duc Pennec, P. Y. Le Roux, P. Y. Salaün, R. Abgral, D. Bourhis y S. Querellou. "The new SPECT/CT reconstruction algorithm xSPECT Bone ® : Reliability and accuracy in daily practice for non-oncologic bone diseases". Médecine Nucléaire 41, n.º 3 (mayo de 2017): 158. http://dx.doi.org/10.1016/j.mednuc.2017.02.055.

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19

Vilhu, O. y A. Collier Cameron. "X-ray Spectral Diagnostics for Coronal Loops in the Active K Dwarf AB Doradus". International Astronomical Union Colloquium 115 (1990): 132–35. http://dx.doi.org/10.1017/s0252921100012239.

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AbstractWe discuss theoretical X-ray spectra for coronal loop models in the rapidly rotating young K dwarf AB Doradus (HD 36705), as a typical representative of active X-ray bright stars. The loop models are based on EXOSAT and IUE observations, and further motivated by a possible connection between the observed X-ray flares and co-rotating clouds of neutral hydrogen (a few/day). The resulting synthetic spectra between 0.5 – 7 keV can be approximated by a linear combination of three distinct temperature components. Two components are sufficient between 0.5 – 2.5 keV. Below 0.1 keV the loop spectra deviate significantly from the few component fits. To test some basic assumptions (dynamic vs. static, constant vs. variable cross-sectional area), useful constraints on the DEM(T)-distribution could be obtained with the grating-spectrometer of XMM with 103 – 104sec exposure times. The ratio of the He-type (O VII) forbidden and intercombination lines at 0.56 keV will provide sufficient density diagnostics, to distinguish e.g.between compact and large loops. The crystal-spectrometers of XMM and XSPECT could achieve the same but with longer (105 sec) observing time. The strong Ly α line of O VIII at 0.65 keV can be observed with the crystals in 104 sec, and used even for rotational modulation and flare studies, and giving additional information about flows in flaring loops. At the Iron 6.7 keV lines, where the gratings do not work, the crystals should be used together with low resolution devices, to set constraints on the hottest gas at loop summits. Our discussion applies also to several brighter cool stars but with shorter observing time (like Capella and HR 1099, which are over 3 times X-ray brighter than AB Dor).
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20

Lima, Thiago V. M., Ujwal Bhure, Maria de Sol Pérez Lago, Yannick Thali, Savo Matijasevic, Justus Roos y Klaus Strobel. "Impact of metal implants on xSPECT/CT Bone reconstruction: the “shining metal artefact”". European Journal of Hybrid Imaging 4, n.º 1 (1 de octubre de 2020). http://dx.doi.org/10.1186/s41824-020-00087-7.

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Abstract Background Novel reconstruction algorithms, such as xSPECT Bone, are gaining more and more importance in Nuclear Medicine. With xSPECT Bone, the reconstructed emission image is enhanced by the information obtained in the corresponding CT image. The CT defines tissue classes according to the Hounsfield units. In the iterative reconstruction, each tissue class is handled separately in the forward projection step, and all together in the back projection step. As a consequence, xSPECT Bone reconstruction generates images with improved boundary delineation and better anatomic representation of tracer activity. Applying this technique, however, showed that artefacts may occur, when no uptake regions, like metal implants, exhibit fictitious uniform tracer uptake. Due to limitations in spatial resolution in gamma cameras, the xSPECT Bone reconstructed image resulted in spill-out activity from surrounding high uptake region being uniformly distributed over the metal implants. This new technology of xSPECT Bone reconstruction in general enhances the image quality of SPECT/CT; however, the potential introduction of specific artefacts which inadvertently come along with this new technology and their frequency have not yet been addressed in the literature. Therefore, the purpose of this work was to identify and characterize these specific metal artefacts (the so-called shining metal artefact) in order to reduce false positives and avoid potentially misdiagnosing loosened or infected implants. Case presentation In this work, we report five cases imaged with bone SPECT/CT of 5 anatomical regions (foot, elbow, spine, shoulder, ribs and knee). All cases demonstrated “shining metal artefacts” in xSPECT Bone reconstruction. Conclusion While xSPECT Bone reconstruction algorithm significantly improves image quality for the diagnosis of bone and joint disorders with SPECT/CT, specific “shining metal artefacts” caused by the xSPECT Bone have to be recognized in order to avoid image misinterpretation suggesting metallic implant loosening or possible infection. The simultaneous analysis of conventionally reconstructed SPECT images (for Siemens the Flash3D reconstruction) helps to avoid misinterpretation of potential artefacts introduced by xSPECT Bone reconstruction.
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Nguyễn, Tuấn Long, Thành Công Phạm y Xuân Ngọc Lê. "NGHIÊN CỨU ỨNG DỤNG CÔNG NGHỆ XỬ LÝ ẢNH XSPECT TRONG GHI HÌNH PHÓNG XẠ SPECT/CT". Tạp chí Y học Việt Nam 526, n.º 2 (1 de junio de 2023). http://dx.doi.org/10.51298/vmj.v526i2.5512.

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Mục tiêu của nghiên cứu: Ứng dụng công nghệ xử lý ảnh xSPECT trong ghi hình phóng xạ SPECT/CT. Đối tượng và phương pháp nghiên cứu: Máy SPECT/CT của hãng Siemens, Đức. Phàn mềm xSPECT; Phan-tom nước; Ghi hình SPECT/CT với thuốc phóng xạ 99mTc-MDP trên bệnh nhân ung thư biểu mô tuyến tiền liệt. Kết quả nghiên cứu: Kết quả dụng bốn phương pháp tái tạo: xSPECT Quant (xQ); xSPECT Xương™ (xB); Flash 3D (F3D); OSEM, cho thấy lập mô hình ma trận hệ thống chính xác hơn là lược đồ cập nhật. Kết quả định lượng của nền và 6 hình cầu bằng cách sử dụng xE, xQ và xB với lấy mẫu góc 3 độ và 6 độ sau nhiều lần cập nhật, tất cả các phương pháp đều đưa ra ước tính rất chính xác (gần 100%) về nền và kết quả ổn định với các bản cập nhật. Kết quả xạ hình xương ở 40 bệnh nhân ung thư tiền liệt tuyến bằng SPECT/CT với 99mTc-MDP đã phát hiện được 50 tổn thương, trong đó: SPECT có 60% (30/50) được cho là không rõ ràng, khi sử dụng XSPECT với SPECT/CT đã làm rõ chẩn đoán ở 52% các tổn thương nghi ngờ chỉ còn 8% (4/50) vẫn không rõ ràng.
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Braun, Martin, Michal Cachovan, Felix Kaul, Federico Caobelli, Markus Bäumer, A. Hans Vija, Geert Pagenstert, Damian Wild y Martin Kretzschmar. "Accuracy comparison of various quantitative [99mTc]Tc-DPD SPECT/CT reconstruction techniques in patients with symptomatic hip and knee joint prostheses". EJNMMI Research 11, n.º 1 (14 de junio de 2021). http://dx.doi.org/10.1186/s13550-021-00794-7.

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Abstract Background There is a need for better diagnostic tools that identify loose total hip and knee arthroplasties. Here, we present the accuracy of different 99mTc-dicarboxypropandiphosphate ([99mTc]Tc-DPD) SPECT/CT quantification tools for the detection of loose prostheses in patients with painful hip and knee arthroplasties. Methods Quantitative reconstruction of mineral phase SPECT data was performed using Siemens xSPECT-Quant and xSPECT-Bone, with and without metal artefact reduction (iMAR) of CT-data. Quantitative data (SUVmax values) were compared to intraoperative diagnosis or clinical outcome after at least 1 year as standard of comparison. Cut-off values and accuracies were calculated using receiver operator characteristics. Accuracy of uptake quantification was compared to the accuracy of visual SPECT/CT readings, blinded for the quantitative data and clinical outcome. Results In this prospective study, 30 consecutive patients with 33 symptomatic hip and knee prostheses underwent [99mTc]Tc-DPD SPECT/CT. Ten arthroplasties were diagnosed loose and 23 stable. Mean-SUVmax was significantly higher around loose prostheses compared to stable prostheses, regardless of the quantification method (P = 0.0025–0.0001). Quantification with xSPECT-Bone-iMAR showed the highest accuracy (93.9% [95% CI 79.6–100%]) which was significantly higher compared to xSPECT-Quant-iMAR (81.8% [67.5–96.1%], P = 0.04) and xSPECT-Quant without iMAR (77.4% [62.4–92.4%], P = 0.02). Accuracies of clinical reading were non-significantly lower compared to quantitative measures (84.8% [70.6–99.1%] (senior) and 81.5% [67.5–96.1%] (trainee)). Conclusion Quantification with [99mTc]Tc-DPD xSPECT-Bone-iMAR discriminates best between loose and stable prostheses of all evaluated methods. The overall high accuracy of different quantitative measures underlines the potential of [99mTc]Tc-DPD-quantification as a biomarker and demands further prospective evaluation in a larger number of prosthesis.
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Kugler, Amelie, Torsten Kuwert, Philipp Ritt y Andreas Grings. "Influence of CT metal artifact reduction on SPECT/CT quantification of bone scintigraphy – Retrospective study for selected types of metal implants". Nuklearmedizin - NuclearMedicine, 9 de agosto de 2022. http://dx.doi.org/10.1055/a-1883-9281.

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Abstract Aim Implanted metal prostheses can cause severe artifacts in reconstructed computed tomography (CT) images. To reduce the diagnostic impact of these artifacts and improve attenuation correction in single photon emission computed tomography (SPECT), an algorithm of iterative metal artifact reduction (iMAR) for SPECT/CT systems was developed. The aims of this study were (a) to assess the difference in visual image quality by comparing CT and SPECT images reconstructed with and without iMAR and (b) to determine the influence of iMAR on quantitative 99mTc-uptake in SPECT/CT. Methods This retrospective study includes 21 patients with implanted metal prostheses who underwent SPECT/CT bone scintigraphy. CT data were reconstructed with iMAR and without (noMAR) and were used for attenuation correction of SPECT data for xSPECT Quant and xSPECT Bone reconstruction. The effect of iMAR on image quality was evaluated by visual analysis and the effect on quantitative SPECT/CT was assessed by measuring HU values and absolute uptake values (kBq/mL) in volumes of interest (VOIs). Results There was a significant reduction of visible metal artifacts with iMAR (p<0.01) in the CT images, but visual differences in the SPECT images were minor. The values of quantitative tracer uptake in VOIs near metal implants were lower for iMAR vs. noMAR xSPECT Quant (p<0.01). Only VOIs near metal showed significant differences in HU values, which were 14.6% lower for iMAR CT (p<0.01). Conclusion The use of iMAR reduces metal artifacts in CT and improves the perceived image quality. Although in some cases a significant difference in the quantitative evaluation of SPECT/CT was observed, the influence of iMAR can be considered small in relation to other factors in the clinical setting.
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Miyaji, Noriaki, Kenta Miwa, Ayaka Tokiwa, Hajime Ichikawa, Takashi Terauchi, Mitsuru Koizumi y Masahisa Onoguchi. "Phantom and clinical evaluation of bone SPECT/CT image reconstruction with xSPECT algorithm". EJNMMI Research 10, n.º 1 (29 de junio de 2020). http://dx.doi.org/10.1186/s13550-020-00659-5.

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Nakajima, Kenichi, Takayuki Shibutani, Francesc Massanes, Takeshi Shimizu, Shohei Yoshida, Masahisa Onoguchi, Seigo Kinuya y A. Hans Vija. "Myocardial perfusion imaging with retrospective gating and integrated correction of attenuation, scatter, respiration, motion, and arrhythmia". Journal of Nuclear Cardiology, 27 de septiembre de 2023. http://dx.doi.org/10.1007/s12350-023-03374-5.

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Abstract Background Absolute quantitative myocardial perfusion SPECT requires addressing of aleatory and epistemic uncertainties in conjunction with providing image quality sufficient for lesion detection and characterization. Iterative reconstruction methods enable the mitigation of the root causes of image degradation. This study aimed to determine the feasibility of a new SPECT/CT method with integrated corrections attempting to enable absolute quantitative cardiac imaging (xSPECT Cardiac; xSC). Methods We compared images of prototype xSC and conventional SPECT (Flash3DTM) acquired at rest from 56 patients aged 71 ± 12 y with suspected coronary heart disease. The xSC prototype comprised list-mode acquisitions with continuous rotation and subsequent iterative reconstructions with retrospective electrocardiography (ECG) gating. Besides accurate image formation modeling, patient-specific CT-based attenuation and energy window-based scatter correction, additionally we applied mitigation for patient and organ motion between views (inter-view), and within views (intra-view) for both the gated and ungated reconstruction. We then assessed image quality, semiquantitative regional values, and left ventricular function in the images. Results The quality of all xSC images was acceptable for clinical purposes. A polar map showed more uniform distribution for xSC compared with Flash3D, while lower apical count and higher defect contrast of myocardial infarction (p = 0.0004) were observed on xSC images. Wall motion, 16-gate volume curve, and ejection fraction were at least acceptable, with indication of improvements. The clinical prospectively gated method rejected beats ≥20% in 6 patients, whereas retrospective gating used an average of 98% beats, excluding 2% of beats. We used the list-mode data to create a product equivalent prospectively gated dataset. The dataset showed that the xSC method generated 18% higher count data and images with less noise, with comparable functional variables of volume and LVEF (p = ns). Conclusions Quantitative myocardial perfusion imaging with the list-mode-based prototype xSPECT Cardiac is feasible, resulting in images of at least acceptable image quality.
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Jreige, Mario, Nicolas Hall, Fabio Becce, Bérengère Aubry-Rozier, Elena Gonzalez Rodriguez, Niklaus Schaefer, John O. Prior y Marie Nicod Lalonde. "A novel approach for fibrous dysplasia assessment using combined planar and quantitative SPECT/CT analysis of Tc-99m-diphosphonate bone scan in correlation with biological bone turnover markers of disease activity". Frontiers in Medicine 9 (25 de noviembre de 2022). http://dx.doi.org/10.3389/fmed.2022.1050854.

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PurposeTo investigate the emerging role of Tc-99m-labeled diphosphonate (Tc-99m-DPD) uptake quantification by SPECT/CT in fibrous dysplasia (FD) bone lesions and its correlation with biological bone turnover markers (BTMs) of disease activity.Materials and methodsSeven patients (49 ± 16 years) with a confirmed diagnosis of FD were included in this retrospective study. Bone scans with Tc-99m-DPD and quantitative SPECT/CT (xSPECT/CT) were performed. SUVmax (maximum standard unit value) and SUVmean (mean standard unit value) were measured in all FD bone lesions. The skeletal burden score (SBS) was assessed on planar scintigraphy and multiplied by mean SUVmax and SUVmean to generate two new parameters, SBS_SUVmax and SBS_SUVmean, respectively. Planar and xSPECT/CT quantitative measures were correlated with biological BTMs of disease activity, including fibroblast growth factor 23 (FGF-23), alkaline phosphatase (ALP), procollagen 1 intact N-terminal propeptide (P1NP) and C-terminal telopeptide (CTX), as well as scoliosis angle measured on radiographs. Statistical significance was evaluated with Spearman’s correlations.ResultsA total of 76 FD bone lesions were analyzed, showing an average SUVmax and SUVmean (g/mL) of 13 ± 7.3 and 8 ± 4.5, respectively. SBS, SBS_SUVmax and SBS_SUVmean values were 30.8 ± 25.6, 358 ± 267 and 220.1 ± 164.5, respectively. Mean measured values of FGF-23 (pg/mL), ALP (U/L), P1NP (μg/L) and CTX (pg/mL) were 98.4 (22–175), 283.5 (46–735), 283.1 (31–1,161) and 494 (360–609), respectively. Mean scoliosis angle was 15.7 (7–22) degrees. We found a very strong positive correlation between planar-derived SBS and CTX (r = 0.96, p = 0.010), but no significant correlation between SUVmax or SUVmean and biological BTMs. SBS_SUVmax showed a strong to very strong positive correlation with CTX (ρ = 0.99, p = 0.002), FGF-23 (ρ = 0.91, p = 0.010), ALP (ρ = 0.82, p = 0.020), and P1NP (ρ = 0.78, p = 0.039), respectively.ConclusionThis study showed that biological BTMs are significantly correlated with diphosphonate uptake on bone scan, quantified by a new parameter combining information from both planar and quantitative SPECT/CT. Further analysis of bone scan quantitative SPECT/CT data in a larger patient population might help better characterize the skeletal disease burden in FD, and guide treatment and follow-up.
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27

Salas-Ramirez, Maikol, Julian Leube, Michael Lassmann y Johannes Tran-Gia. "Effect of kilovoltage and quality reference mAs on CT-based attenuation correction in 177Lu SPECT/CT imaging: a phantom study". EJNMMI Physics 11, n.º 1 (26 de febrero de 2024). http://dx.doi.org/10.1186/s40658-024-00622-6.

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Abstract Introduction CT-based attenuation correction (CT-AC) plays a major role in accurate activity quantification by SPECT/CT imaging. However, the effect of kilovoltage peak (kVp) and quality-reference mAs (QRM) on the attenuation coefficient image (μ-map) and volume CT dose index (CTDIvol) have not yet been systematically evaluated. Therefore, the aim of this study was to fill this gap and investigate the influence of kVp and QRM on CT-AC in 177Lu SPECT/CT imaging. Methods Seventy low-dose CT acquisitions of an Electron Density Phantom (seventeen inserts of nine tissue-equivalent materials) were acquired using various kVp and QRM combinations on a Siemens Symbia Intevo Bold SPECT/CT system. Using manufacturer reconstruction software, 177Lu μ-maps were generated for each CT image, and three low-dose CT related aspects were examined. First, the μ-map-based attenuation values (μmeasured) were compared with theoretical values (μtheoretical). Second, changes in 177Lu activity expected due to changes in the μ-map were calculated using a modified Chang method. Third, the noise in the μ-map was assessed by measuring the coefficient of variation in a volume of interest in the homogeneous section of the Electron Density Phantom. Lastly, two phantoms were designed to simulate attenuation in four tissue-equivalent materials for two different source geometries (1-mL and 10-mL syringes). 177Lu SPECT/CT imaging was performed using three different reconstruction algorithms (xSPECT Quant, Flash3D, STIR), and the SPECT-based activities were compared against the nominal activities in the sources. Results The largest relative errors between μmeasured and μtheoretical were observed in the lung inhale insert (range: 18%-36%), while it remained below 6% for all other inserts. The resulting changes in 177Lu activity quantification were -3.5% in the lung inhale insert and less than -2.3% in all other inserts. Coefficient of variation and CTDIvol ranged from 0.3% and 3.6 mGy (130 kVp, 35 mAs) to 0.4% and 0.9 mGy (80 kVp, 20 mAs), respectively. The SPECT-based activity quantification using xSPECT Quant reconstructions outperformed all other reconstruction algorithms. Conclusion This study shows that kVp and QRM values in low-dose CT imaging have a minimum effect on quantitative 177Lu SPECT/CT imaging, while the selection of low values of kVp and QRM reduce the CTDIvol.
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28

Duncan, Iain y Nicholas Ingold. "The clinical value of xSPECT/CT Bone versus SPECT/CT. A prospective comparison of 200 scans". European Journal of Hybrid Imaging 2, n.º 1 (19 de marzo de 2018). http://dx.doi.org/10.1186/s41824-017-0024-9.

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Shibutani, Takayuki, Takahiro Konishi, Hajime Ichikawa, Masahisa Onoguchi, Hiroto Yoneyama, Toshimune Ito, Koichi Okuda y Kenichi Nakajima. "Detectability of cold tumors by xSPECT bone technology compared with hot tumors: a supine phantom study". Physical and Engineering Sciences in Medicine, 20 de diciembre de 2023. http://dx.doi.org/10.1007/s13246-023-01364-y.

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30

Sézin, G., P. Lalire, C. Hoog, A. Moubtakir, S. Dejust, K. El Farsaoui, D. Morland y D. Papathanassiou. "Évaluation de la modalité de reconstruction xSPECT bone dans la détection de lésions osseuses secondaires en scintigraphie osseuse". Médecine Nucléaire, enero de 2024. http://dx.doi.org/10.1016/j.mednuc.2023.09.009.

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31

Mallaev, M., A.-F. Chirindel, G. Nicolas, M. Tamm, A. Hojski, M. Wiese, D. Stolz y D. Lardinois. "3D-quantitated lung perfusion SPECT/CT: Impact on intended management compared to lung perfusion scan in marginal candidates for lung resection surgery". British Journal of Surgery 109, Supplement_3 (31 de mayo de 2022). http://dx.doi.org/10.1093/bjs/znac185.001.

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Abstract Objective Based on previous studies, single-photon emission computed tomography/computed tomography (SPECT/CT) has been proven to be more accurate and reproducible than planar lung perfusion scintigraphy. We conducted a study to evaluate the impact of 3D-quantitated lung perfusion SPECT/CT on intended management in candidates for lung resection surgery. Methods Retrospective study including candidates for lung resection surgery with lung perfusion imaging. Patients underwent preoperative evaluation according to ERS/ESTS algorithm. The lobar contribution to the total lung perfusion was estimated using planar antero-posterior, posterior oblique and three-dimensional anatomical SPECT/CT method (CT Pulmo 3D and xSPECT- Quant, Siemens). The difference in lobar perfusion with resulting changes in the extent of lung resection were analyzed to reveal possible changes in operability. Results 120 patients (46 females) with known lung cancer or pulmonary lesion considered for resection with available lung perfusion scintigraphy and SPECT/CT were enrolled. The mean age (±SD) of patients was 68 ±9 years, the target lesions were located in upper lobe in 57.7% and in lower lobe in 33.5%. The median [IQR] FEV1 was 70.5% [52–84] and median DLCO 56.6% [47.1–67.4]. The planar posterior oblique method, compared to 3D-quantitated SPECT/CT, underestimated the perfusion of upper lobes by a median difference of 5% (right [2–9; IQR]; left [2.5–8], p= &lt; 0.0001), while it overestimated the both lower lobes (left by 4% [2–7]; right by 6% [2–9], p= &lt; 0.0001). In contrast to the planar scintigraphy based evaluation, 4(3.3%) patients with upper lobe lesions were classified as inoperable when 3D-quantitated SPECT/CT was used for calculation of predicted postoperative lung function. Conclusion In selected patients with upper lobe lesions, 3D-quantitated SPECT/CT would have changed the treatment strategy from operable to inoperable. Importantly, post-operative mortality in this particular subgroup was disproportionally high. 3D-quantitated SPECT/CT shall be further evaluated as it might improve preoperative risk stratification in marginal lung resection candidates.
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32

Tabotta, Flavian, Mario Jreige, Niklaus Schaefer, Fabio Becce, John O. Prior y Marie Nicod Lalonde. "Quantitative bone SPECT/CT: high specificity for identification of prostate cancer bone metastases". BMC Musculoskeletal Disorders 20, n.º 1 (diciembre de 2019). http://dx.doi.org/10.1186/s12891-019-3001-6.

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Abstract Purpose Bone scintigraphy with 99mTc-labeled diphosphonates can identify prostate cancer bone metastases with high sensitivity, but relatively low specificity, because benign conditions such as osteoarthritis can also trigger osteoblastic reactions. We aimed to investigate the diagnostic performance of 99mTc-2,3-dicarboxy propane-1,1-diphosphonate (99mTc-DPD) uptake quantification by single-photon emission computed tomography coupled with computed tomography (SPECT/CT) for distinguishing prostate cancer bone metastases from spinal and pelvic osteoarthritic lesions. Methods We retrospectively assessed 26 bone scans from 26 patients with known prostate cancer bone metastases and 13 control patients with benign spinal and pelvic osteoarthritic changes without known neoplastic disease. Quantitative SPECT/CT (xSPECT, Siemens Symbia Intevo, Erlangen, Germany) was performed and standardized uptake values (SUVs) were quantified with measurements of SUVmax and SUVmean (g/mL) in all bone metastases for the prostate cancer group and in spinal and pelvic osteoarthritic changes for the control group. We used receiver operating characteristics (ROC) curves to determine the optimum SUVmax cutoff value to distinguish between bone metastases and benign spinal and pelvic lesions. Results In total, 264 prostate cancer bone metastases were analyzed, showing a mean SUVmax and SUVmean of 34.6 ± 24.6 and 20.8 ± 14.7 g/mL, respectively. In 24 spinal and pelvic osteoarthritic lesions, mean SUVmax and SUVmean were 14.2 ± 3.8 and 8.9 ± 2.2 g/mL, respectively. SUVmax and SUVmean were both significantly different between the bone metastases and osteoarthritic groups (p ≤ 0.0001). Using a SUVmax cutoff of 19.5 g/mL for prostate cancer bone metastases in the spine and pelvis, sensitivity, specificity, positive and negative predictive values were 87, 92, 99 and 49%, respectively. Conclusion This study showed significant differences in quantitative 99mTc-DPD uptake on bone SPECT/CT between prostate cancer bone metastases and spinal and pelvic osteoarthritic changes, with higher SUVmax and SUVmean in metastases. Using a SUVmax cutoff of 19.5 g/mL, high specificity and positive predictive value for metastases identification in the spine and pelvis were found, thus increasing accuracy of bone scintigraphy.
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33

Hughes, Daniel Johnathan, Gitasha Chand, Jessica Johnson, Damion Bailey, Kathryn Adamson, Vicky Goh y Gary J. R. Cook. "Inter-rater and intra-rater agreement of [99mTc]-labelled NM-01, a single-domain programmed death-ligand 1 (PD-L1) antibody, using quantitative SPECT/CT in non-small cell lung cancer". EJNMMI Research 13, n.º 1 (31 de mayo de 2023). http://dx.doi.org/10.1186/s13550-023-01002-4.

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Abstract Background Immune checkpoint inhibitors, including those against programmed cell death protein-1 (PD-1) or its ligand (PD-L1), are routinely used to treat non-small cell lung cancer (NSCLC). PD-L1 is a validated prognostic and predictive immunohistochemical biomarker of anti-PD-1/PD-L1 therapy but displays temporospatial heterogeneity of expression. Non-invasive radiopharmaceutical techniques, including technetium-99m [99mTc]-labelled anti-PD-L1 single-domain antibody (NM-01) SPECT/CT, have the potential to improve the predictive value of PD-L1 assessment. This study aims to determine the inter- and intra-rater agreement of the quantitative measurement of [99mTc]NM-01 SPECT/CT in NSCLC. Methods Participants (n = 14) with untreated advanced NSCLC underwent [99mTc]NM-01 SPECT/CT at baseline (n = 3) or at baseline plus 9-week follow-up (n = 11). [99mTc]NM-01 uptake (of primary lung, lymph node, thoracic and distant metastases, and healthy reference tissues) was measured using SUVmax and malignant lesion-to-blood pool ratios with Siemens xSPECT Broad Quantification software by three independent raters. Intraclass correlation coefficients (ICC) were calculated and Bland–Altman plot analysis performed to determine inter- and intra-rater agreement. Results There was excellent inter-rater agreement of manual freehand SUVmax scores of primary lung tumour (T; n = 25; ICC 1.00; 95% CI 0.99–1.00), individual lymph node metastases (LN; n = 56; ICC 0.97; 95% CI 0.95–0.98), thoracic metastases (ThMet; n = 9; ICC 0.94; 95% CI 0.83–0.99) and distant metastases (DisMet; n = 21; ICC 0.91; 95% CI 0.83–0.96). The inter-rater ICCs of tumour-to-blood pool (T:BP), LN:BP, ThMet:BP and DisMet:BP measures of [99mTc]NM-01 uptake also demonstrated good or excellent agreement. Manual freehand scoring of T, LN, ThMet, DisMet and their ratios using [99mTc]NM-01 SPECT/CT following a 28-day interval was consistent for all raters with good or excellent intra-rater agreement demonstrated (ICCs range 0.86–1.00). Conclusion Quantitative assessment of [99mTc]NM-01 SPECT/CT in NSCLC, using SUVmax of malignant primary or metastatic lesions and their ratios with healthy reference tissues, demonstrated good or excellent inter- and intra-rater agreement in this study. Further validation with ongoing and future larger cohort studies is now warranted. Clinical trial registration ClinicalTrials.gov identifier no. NCT04436406 (registered 18th June 2020; available at https://clinicaltrials.gov/ct2/show/NCT04436406) and NCT04992715 (registered 5th August 2021; available at https://clinicaltrials.gov/ct2/show/NCT04992715).
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