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Despite the use of surgical resection and chemotherapy in the clinical treatment of oral squamous cell carcinoma (OSCC), the 5-year survival rates of advanced patients are low. Therefore, more efficient strategies are urgently needed. Herein, a chemo/ferroptosis synergistic therapeutic system-DMEFe nanoparticles (NPs) is established for the treatment of OSCC. To create this system, the chemotherapeutic agent doxorubicin (DOX) was loaded into mesoporous silica nanoparticles and further coated with a pH-sensitive metal polyphenol (iron ion and epigallocatechin gallate). These nanoparticles displayed excellent pH-sensitive drug-control release properties, and the release ratio of DOX at pH 5.5 was twice as high than that at pH 7.4. Additionally, DMEF NPs were effectively taken up by the OSCC cell line SSC-25, which greatly impeded the proliferation of these cells. Notably, these nanoparticles increased the intracellular level of reactive oxygen species and effectively exhibited cytotoxity effects. The mechanistic results proved that DMEFe NPs regulated the expression of ferroptosis-related genes to induce ferroptosis of SSC-25 cells. Eventually, this chemo/ferroptosis therapeutic system exhibited remarkable antitumor effects and provided a novel strategy for the treatment of OSCC.
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INTRODUCTION: This study aimed to evaluate the clinical value of iodine-131 combined with levothyroxine sodium in the treatment of patients with differentiated thyroid cancer (DTC) after surgery. METHODS: Prospective randomized controlled studies were conducted. A total of 374 DTC patients who underwent total or near-total thyroidectomy in the Department of Thyroid Surgery, Tianjin Union Medical Center and Tianjin Medical University General Hospital, from January 2019 to February 2022 were selected and divided into control group (187 cases) and observation group (187 cases) according to random number table method. The control group was treated with levothyroxine sodium after surgery, and the observation group was treated with iodine-131 on the basis of the control group. Gender, age, course of disease, tumor diameter, pathological type, TNM classification, treatment effect, thyroglobulin (Tg) levels before and after treatment, SF-36 health status questionnaires (SF-36), occurrence of adverse reactions after treatment, and recurrence rate of 1-year follow-up were compared and analyzed between the two groups. RESULTS: There was no significant difference in baseline data between the two groups. After treatment, the effective rate of the observation group increased by 11.23% compared to the control group, with a statistically significant difference (91.98% vs. 80.75%, p < 0.05). There was no significant difference in Tg level and scores of SF-36 evaluation including physical functioning, physical problems, vitality, pain, mental health, emotional problems, social functioning, and general health perception between the two groups before surgery (p > 0.05), Tg levels and scores of SF-36 evaluation in all dimensions were significantly improved in both groups after treatment (p < 0.05), and the levels of Tg and scores of SF-36 in all dimensions in observation group were significantly better than those in control group after treatment (p < 0.001). There was no significant difference in the incidence of adverse reactions between the two groups (p > 0.05). The recurrence rate in the observation group was 5.89% lower than that in the control group 1 year after treatment, with a statistically significant difference (2.67% vs. 8.56%, p < 0.05). CONCLUSIONS: The combination of iodine-131 and levothyroxine sodium in the postoperative treatment of DTC can improve the therapeutic effect and reduce the postoperative recurrence rate without increasing adverse reactions, which is worthy of clinical reference and promotion.
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Survival of the immobile embryo in response to rising temperature is important to determine a species' vulnerability to climate change. However, the collective effects of 2 key thermal characteristics associated with climate change (i.e., rising average temperature and acute heat events) on embryonic survival remain largely unexplored. We used empirical measurements and niche modeling to investigate how chronic and acute heat stress independently and collectively influence the embryonic survival of lizards across latitudes. We collected and bred lizards from 5 latitudes and incubated their eggs across a range of temperatures to quantify population-specific responses to chronic and acute heat stress. Using an embryonic development model parameterized with measured embryonic heat tolerances, we further identified a collective impact of embryonic chronic and acute heat tolerances on embryonic survival. We also incorporated embryonic chronic and acute heat tolerance in hybrid species distribution models to determine species' range shifts under climate change. Embryos' tolerance of chronic heat (T-chronic) remained consistent across latitudes, whereas their tolerance of acute heat (T-acute) was higher at high latitudes than at low latitudes. Tolerance of acute heat exerted a more pronounced influence than tolerance of chronic heat. In species distribution models, climate change led to the most significant habitat loss for each population and species in its low-latitude distribution. Consequently, habitat for populations across all latitudes will shift toward high latitudes. Our study also highlights the importance of considering embryonic survival under chronic and acute heat stresses to predict species' vulnerability to climate change.
Efectos colectivos del aumento de las temperaturas promedio y los eventos de calor en embriones ovíparos Resumen La supervivencia de los embriones inmóviles en respuesta al incremento de temperatura es importante para determinar la vulnerabilidad de las especies al cambio climático. Sin embargo, los efectos colectivos de dos características térmicas claves asociadas con el cambio climático (i. e., aumento de temperatura promedio y eventos de calor agudo) sobre la supervivencia embrionaria permanecen en gran parte inexplorados. Utilizamos mediciones empíricas y modelos de nicho para investigar cómo el estrés térmico crónico y agudo influye de forma independiente y colectiva en la supervivencia embrionaria de los lagartos en todas las latitudes. Recolectamos y criamos lagartos de cinco latitudes e incubamos sus huevos en un rango de temperaturas para cuantificar las respuestas específicas de la población al estrés por calor crónico y agudo. Posteriormente, mediante un modelo de desarrollo embrionario parametrizado con mediciones de tolerancia embrionaria al calor, identificamos un impacto colectivo de las tolerancias embrionarias al calor agudo y crónico en la supervivencia embrionaria. También incorporamos la tolerancia embrionaria crónica y aguda al calor en modelos de distribución de especies híbridas para determinar los cambios de distribución de las especies bajo el cambio climático. La tolerancia embrionaria al calor crónico (Tcrónico) permaneció constante, mientras que la tolerancia al calor agudo (Tagudo) fue mayor en latitudes altas que en latitudes bajas. La tolerancia al calor agudo ejerció una influencia más pronunciada que la tolerancia al calor crónico. En los modelos de distribución de especies, el cambio climático provocó la pérdida de hábitat más significativa para cada población y especie en su distribución de latitudes bajas. En consecuencia, el hábitat para poblaciones en todas las latitudes se desplazará a latitudes altas. Nuestro estudio también resalta la importancia de considerar la supervivencia embrionaria bajo estrés térmico crónico y agudo para predecir la vulnerabilidad de las especies al cambio climático.
Subject(s)
Climate Change , Embryo, Nonmammalian , Hot Temperature , Lizards , Animals , Lizards/physiology , Lizards/embryology , Embryo, Nonmammalian/physiology , Oviparity , Female , Models, Biological , Embryonic Development , ThermotoleranceABSTRACT
BACKGROUND: The curriculum system is a central component in achieving the goals and specifications of talent training schemes. However, problems and difficulties exist in curriculum provision due to a lack of curriculum system design logic. This study aimed to investigate the correlation between the university curriculum system and graduate quality and to reveal the design logic of the curriculum system. METHODS: A total of 699 stomatology graduates from a university in Zhejiang were selected as research subjects from 2015 to 2022. The students' curriculum system and graduate quality data were collected and classified. The graduate quality information contained (1) the National Board Dental Examination (NBDE) pass rate and score, (2) the postgraduate entrance rate and destination, and (3) the employment rate and work institution. Regression analysis was also conducted to assess the correlation between the curriculum system and graduate quality. RESULTS: Regression analysis revealed significant associations between general education, specialization, and stomatology X courses and NBDE score, postgraduate entrance rate and destination, and work institution. All courses except public elective courses had significant impacts on NBDE score. General basic, medical English, and employment guidance courses significantly influenced the postgraduate entrance rate and destination. Restricted elective and public elective courses had significant effects on employment rate and work institution. CONCLUSIONS: Increasing the quality of specialized and stomatology X courses in the curriculum system is beneficial for deepening graduates' expertise and enhancing their education. Moreover, English courses are suggested to be offered in the early stage to lay a better language foundation.
Subject(s)
Curriculum , Humans , China , Multivariate Analysis , Educational Measurement , Oral Medicine/education , Female , MaleABSTRACT
Thyroid cancer is a highly differentiated and poorly malignant tumor. Interfering with glycolysis has become an effective means of controlling cancer progression and autophagy is negatively correlated with glycolysis. Aldo-keto reductase family 1 member C3 (AKR1C3) has been demonstrated to be highly expressed in thyroid cancer tissue and the higher AKR1C3 expression predicted the worse prognosis. We aimed to explore whether AKR1C3 could affect thyroid cancer progression by regulating autophagy-dependent glycolysis. AKR1C3 expression in thyroid cancer cells was detected by western blot. Then, AKR1C3 was knocked down by transfection with short hairpin RNA specific to AKR1C3 in the absence or presence of 3-methyladenine (3-MA) or PMA treatment. Cell cycle and apoptosis was detected by flow cytometry. Immunofluorescence staining was used to analyze LC3B expression. Extracellular acidification, glucose uptake and lactic acid secretion were detected. To evaluate the tumorigenicity of AKR1C3 insufficiency on thyroid cancer in vivo, TPC-1 cells with AKR1C3 knockdown were injected subcutaneously into nude mice. Then, cyclinD1 and Ki67 expression in tumorous tissues was measured by immunohistochemical analysis. Apoptosis was assessed by terminal-deoxynucleoitidyl transferase mediated nick end labeling staining. Additionally, the expression of proteins related to cell cycle, apoptosis, glycolysis, autophagy, and extracellular signal-regulated kinase (ERK) signaling in cells and tumor tissues was assessed by western blot. Highly expressed AKR1C3 was observed in thyroid cancer cells. AKR1C3 knockdown induced cell cycle arrest and apoptosis of TPC-1 cells. Besides, autophagy was activated and glycolysis was inhibited following AKR1C3 silencing, and 3-MA treatment restored the impacts of AKR1C3 silencing on glycolysis. The further experiments revealed that AKR1C3 insufficiency inhibited ERK signaling and PMA application reversed AKR1C3 silencing-induced autophagy in TPC-1 cells. The in vivo results suggested that AKR1C3 knockdown inhibited the development of subcutaneous TPC-1 tumors in nude mice and inactivated the ERK signaling. Collectively, AKR1C3 silencing inhibited autophagy-dependent glycolysis in thyroid cancer by inactivating ERK signaling.
Subject(s)
Extracellular Signal-Regulated MAP Kinases , Thyroid Neoplasms , Animals , Mice , Aldo-Keto Reductase Family 1 Member C3 , Autophagy , Glycolysis , Mice, Nude , Thyroid Neoplasms/genetics , HumansABSTRACT
As one of the three major outdoor components of the railroad signal system, the track circuit plays an important role in ensuring the safety and efficiency of train operation. Therefore, when a fault occurs, the cause of the fault needs to be found quickly and accurately and dealt with in a timely manner to avoid affecting the efficiency of train operation and the occurrence of safety accidents. This article proposes a fault diagnosis method based on multi-scale attention network, which uses Gramian Angular Field (GAF) to transform one-dimensional time series into two-dimensional images, making full use of the advantages of convolutional networks in processing image data. A new feature fusion training structure is designed to effectively train the model, fully extract features at different scales, and fusing spatial feature information through spatial attention mechanisms. Finally, experiments are conducted using real track circuit fault datasets, and the accuracy of fault diagnosis reaches 99.36%, and our model demonstrates better performance compared to classical and state-of-the-art models. And the ablation experiments verified that each module in the designed model plays a key role.
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In this study, the diversity and regularity of two new feline calicivirus (FCV) isolates, QD-7 and QD-164, were investigated. The genomes of these new strains were compared with 39 strains from the NCBI database including isolates from China, United States, Germany, South Korea, the United Kingdom and Japan. The nucleotide sequence identities ranged from 75-88%, indicating a high degree of variability. These variations were not related to distributions of the virus by time of isolation and geographical location. Cats that were experimentally infected with the new isolate QD-164 showed typical clinical symptoms of sneezing, fever and conjunctivitis and all recovered within 30 days. In contrast, QD-7 infections were asymptomatic and the virus was cleared within 16 days. These results indicate that QD-7 and QD-164 were naturally attenuated strains. NNS mutations characteristic of highly virulent strains at positions 441-443 were absent in QD-7 while QD-164 possessed an N at position 442. This indicated that mutations in regions 441-443 may be linked to disease severity.
Subject(s)
Caliciviridae Infections , Calicivirus, Feline , Cat Diseases , Cats , Animals , Calicivirus, Feline/genetics , Virulence/genetics , Caliciviridae Infections/veterinary , Base Sequence , ChinaABSTRACT
Background: Efferocytosis of apoptotic neurons by macrophages is essential for the resolution of inflammation and for neuronal protection from secondary damage. It is known that alteration of the Sigma-1 receptor (Sig-1R) is involved in the pathological development of some neurological diseases, including ischemic stroke. The present study aimed to investigate whether and how Sig-1R regulates the phagocytic activity of macrophages/microglia and its significance in neuroprotection and neurological function in stroke. Methods: The roles of Sig-1R in the efferocytosis activity of microglia/macrophages using bone marrow-derived macrophages (BMDMs) or using Sig-1R knockout mice subjected to transient middle artery occlusion (tMCAO)-induced stroke were investigated. The molecular mechanism of Sig-1R in the regulation of efferocytosis was also explored. Adoptive transfer of Sig-1R intact macrophages to recipient Sig-1R knockout mice with tMCAO was developed to observe its effect on apoptotic neuron clearance and stroke outcomes. Results: Depletion of Sig-1R greatly impaired the phagocytic activity of macrophages/microglia, accordingly with worsened brain damage and neurological defects in Sig-1R knockout mice subjected to tMCAO. Adoptive transfer of Sig-1R intact bone marrow-derived macrophages (BMDMs) to Sig-1R knockout mice restored the clearance activity of dead/dying neurons, reduced infarct area and neuroinflammation, and improved long-term functional recovery after cerebral ischemia. Mechanistically, Sig-1R-mediated efferocytosis was dependent on Rac1 activation in macrophages, and a few key sites of Rac1 in its binding pocket responsible for the interaction with Sig-1R were identified. Conclusion: Our data provide the first evidence of the pivotal role of Sig-1R in macrophage/microglia-mediated efferocytosis and elucidate a novel mechanism for the neuroprotection of Sig-1R in ischemic stroke.
Subject(s)
Apoptosis , Ischemic Stroke , Neuroprotection , Animals , Mice , Ischemic Stroke/pathology , Macrophages/metabolism , Mice, Inbred C57BL , Mice, Knockout , Microglia/metabolism , Neurons/pathology , Sigma-1 ReceptorABSTRACT
Tensor fields are useful for modeling the structure of biological tissues. The challenge to measure tensor fields involves acquiring sufficient data of scalar measurements that are physically achievable and reconstructing tensors from as few projections as possible for efficient applications in medical imaging. In this paper, we present a filtered back-projection algorithm for the reconstruction of a symmetric second-rank tensor field from directional X-ray projections about three axes. The tensor field is decomposed into a solenoidal and irrotational component, each of three unknowns. Using the Fourier projection theorem, a filtered back-projection algorithm is derived to reconstruct the solenoidal and irrotational components from projections acquired around three axes. A simple illustrative phantom consisting of two spherical shells and a 3D digital cardiac diffusion image obtained from diffusion tensor MRI of an excised human heart are used to simulate directional X-ray projections. The simulations validate the mathematical derivations and demonstrate reasonable noise properties of the algorithm. The decomposition of the tensor field into solenoidal and irrotational components provides insight into the development of algorithms for reconstructing tensor fields with sufficient samples in terms of the type of directional projections and the necessary orbits for the acquisition of the projections of the tensor field.
Subject(s)
Algorithms , Tomography, X-Ray Computed , Humans , Tomography, X-Ray Computed/methods , Tomography , Phantoms, Imaging , Imaging, Three-Dimensional/methods , Image Processing, Computer-Assisted/methodsABSTRACT
PURPOSE: The time-of-flight (TOF) information improves signal-to-noise ratio (SNR) for positron emission tomography (PET) imaging. Existing analytical algorithms for TOF PET usually follow a filtered back-projection process on reconstructing images from the sinogram data. This work aims to develop a back-projection-and-filtering-like (BPF-like) algorithm that reconstructs the TOF PET image directly from listmode data rapidly. METHODS: We extended the 2D conventional non-TOF PET projection model to a TOF case, where projection data are represented as line integrals weighted by the one-dimensional TOF kernel along the projection direction. After deriving the central slice theorem and the TOF back-projection of listmode data, we designed a deep learning network with a modified U-net architecture to perform the spatial filtration (reconstruction filter). The proposed BP-Net method was validated via Monte Carlo simulations of TOF PET listmode data with three different time resolutions for two types of activity phantoms. The network was only trained on the simulated full-dose XCAT dataset and then evaluated on XCAT and Jaszczak data with different time resolutions and dose levels. RESULTS: Reconstructed images show that when compared with the conventional BPF algorithm and the MLEM algorithm proposed for TOF PET, the proposed BP-Net method obtains better image quality in terms of peak signal-to-noise ratio, relative mean square error, and structure similarity index; besides, the reconstruction speed of the BP-Net is 1.75 times faster than BPF and 29.05 times faster than MLEM using 15 iterations. The results also indicate that the performance of the BP-Net degrades with worse time resolutions and lower tracer doses, but degrades less than BPF or MLEM reconstructions. CONCLUSION: In this work, we developed an analytical-like reconstruction in the form of BPF with the reconstruction filtering operation performed via a deep network. The method runs even faster than the conventional BPF algorithm and provides accurate reconstructions from listmode data in TOF-PET, free of rebinning data to a sinogram.
Subject(s)
Deep Learning , Image Processing, Computer-Assisted , Algorithms , Image Processing, Computer-Assisted/methods , Phantoms, Imaging , Positron-Emission Tomography/methods , Signal-To-Noise RatioABSTRACT
PURPOSE: Single photon emission computed tomography (SPECT) scanners using cadmium zinc telluride (CZT) offer compact, lightweight, and improved imaging capability over conventional NaI(Tl)-based SPECT scanners. The main purpose in this study is to propose a full-ring SPECT system design with eight large-area CZT detectors that can be used for a broad spectrum of SPECT radiopharmaceuticals and demonstrate the performance of our system in comparison to the reference conventional NaI(Tl)-based two-head Anger cameras. METHODS: A newly designed full-ring SPECT system is composed of eight large-area CZT cameras (128 mm × 179.2 mm effective area) that can be independently swiveled around their own axes of rotation independently and can have radial motion for varying aperture sizes that can be adapted to different sizes of imaging volume. Extended projection data were generated by conjoining projections of two adjacent detectors to overcome the limited field-of-view (FOV) by each CZT camera. Using Monte Carlo simulations, we evaluated this new system design with digital phantoms including a Derenzo hot rod phantom and a Zubal brain phantom. Comparison of performance metrics such as spatial resolution, sensitivity, contrast-to-noise ratio (CNR), and contrast-recovery ratio was made between our design and conventional SPECT scanners having different pixel sizes and radii of rotation (one clinically well-known type and two arbitrary types matched to our proposed CZT-SPECT geometries). RESULTS: The proposed scanner could result in up to about three times faster in acquisition time over conventional scan time at same acquisition time per step. The spatial resolution improvement, or deterioration, of our proposed scanner compared to the clinical-type scanner was dependent upon the location of the point source. However, there were overall performance improvements over the three different setups of the conventional scanner particularly in volume sensitivity (approximately up to 1.7 times). Overall, we successfully reconstructed the phantom image for both 99m Tc-based perfusion and 123 I-based dopamine transporter (DaT) brain studies simulated for our new design. In particular, the striatal/background contrast-recovery ratio in 3-to-1 reference ratio was over 0.8 for the 123 I-based DaT study. CONCLUSIONS: We proposed a variable-aperture full-ring SPECT system using combined pixelated CZT and energy-optimized parallel-hole collimator modules and evaluated the performance of this scanner using relevant digital phantoms and MC simulations. Our studies demonstrated the potential of our new full-ring CZT-SPECT design, showing reduced acquisition time and improved sensitivity with acceptable CNR and spatial resolution.
Subject(s)
Cadmium , Tellurium , Brain/diagnostic imaging , Phantoms, Imaging , Tomography, Emission-Computed, Single-Photon , ZincABSTRACT
PURPOSE: In this work, we present tomographic simulations of a new hardware concept for X-ray phase-contrast interferometry wherein the phase gratings are replaced with an array of Fresnel biprisms, and Moiré fringe analysis is used instead of "phase stepping" popular with grating-based setups. METHODS: Projections of a phantom consisting of four layers of parallel carbon microfibers is simulated using wave optics representation of X-ray electromagnetic waves. Simulated projections of a phantom with preferential scatter perpendicular to the direction of the fibers are performed to analyze the extraction of small-angle scatter from dark-field projections for the following: (1) biprism interferometry using Moiré fringe analysis; (2) grating interferometry using phase stepping with eight grating steps; and (3) grating interferometry using Moiré fringe analysis. Dark-field projections are modeled as projections of voxel intensities represented by a fixed finite vector basis set of scattering directions. An iterative MLEM algorithm is used to reconstruct, from simulated projection data, the coefficients of a fixed set of seven basis vectors at each voxel representing the small-angle scatter distribution. RESULTS: Results of reconstructed vector coefficients are shown comparing the three simulated imaging configurations. The single-exposure Moiré fringe analysis shows not only an increase in noise because of one-eighth the number of projection samples but also is obtained with less dose and faster acquisition times. Furthermore, replacing grating interferometry with biprism interferometry provides better contrast-to-noise. CONCLUSION: The simulations demonstrate the feasibility of the reconstruction of dark-field data acquired with a biprism interferometry system. With the potential of higher fringe visibility, biprism interferometry with Moiré fringe analysis might provide equal or better image quality to that of phase stepping methods with less imaging time and lower dose.
Subject(s)
Interferometry , Tomography, X-Ray Computed , Computer Simulation , Radiography , X-RaysABSTRACT
A practical wearable brain PET scanner capable of dynamic neuroimaging during free bodily movement will enable potential breakthrough basic neuroscience studies and help develop imaging-based neurological diagnoses and treatments. Weight, brain coverage, and sensitivity are three fundamental technical obstacles in the development of Fully Wearable High-Performance (FWHP) brain PET scanners. The purpose of this study is to investigate the feasibility of building a FWHP brain PET using a limited volume of lutetium-yttrium oxyorthosilicate (LYSO) scintillator crystals. Six scanners, consisted of the same volume (2.66 kg) of LYSO scintillators with combinations of 2 different crystal pitches (3 mm and 1.5 mm) and 3 different crystal lengths (20 mm, 10 mm, and 5 mm), were simulated. The performances of the six scanners were assessed and compared with Siemen's HRRT brain PET and mCT whole-body PET, in terms of aperture, axial field of views (AFOV), sensitivity, spatial resolution, count rates, and image noise property. The time-of-flight (TOF) information was included in the image reconstruction to improve the effective sensitivity. The effects of the TOF was assessed by scanning a Jaszczak phantom and reconstructing images with the maximum likelihood expectation maximization (MLEM) algorithm with different timing settings (non-TOF, 500 ps, 200 ps, 100 ps and 50 ps Coincidence Time Resolution, CTR). The signal-noise ratio (SNR) of the images were assessed and compared with those of the HRRT scanner and mCT scanner. The results show that it is possible to construct a FWHP brain PET with better spatial resolution than the dedicated HRRT brain PET, comparable effective sensitivity (with 50 â¼ 100 ps CTR), and whole-brain coverage (23.7 cm inner diameter and 13.4 cm axial field of view) using 2.66 kg of LYSO.
Subject(s)
Brain/diagnostic imaging , Equipment Design , Neuroimaging/instrumentation , Positron-Emission Tomography/instrumentation , Wearable Electronic Devices , Algorithms , Image Processing, Computer-Assisted , Lutetium/chemistry , Phantoms, Imaging , Scintillation Counting , Silicates/chemistry , Yttrium/chemistryABSTRACT
This paper presents a unique preclinical positron emission tomography (PET) detector constructed with a monolithic scintillator ring (MSR) and two rings of silicon photomultipliers (SiPM). The inner diameter, outer diameter and length of the MSR were 48.5 mm, 58.5 mm, and 25.1 mm, respectively. The two SiPM rings, constructed with 46 SiPMs, were air-coupled to the two ends of the MSR detector. The center of gravity (COG) and artificial neural network (ANN) methods were adapted to decode the positions of the gamma interactions in the circumferential (θ) and axial (Z) directions, respectively. Collimating systems, consisting of a tungsten collimator and a high-precision displacement and rotating platform, were constructed to assess the decoding accuracies of the MSR detector in both θ and Z directions. The average intrinsic full-width half maximums (FWHMs) and mean absolute errors (MAEs) of the decoding accuracies were 0.94 mm and 0.33 mm in the circumferential direction, 2.45 mm and 1.08 mm in the axial direction. An energy resolution of 10.7% was measured at 511 keV. The scintillating photons generated by a pair of coincidence gamma photons overlap with each other, and cause circumferential parallax errors in the lines of response (LOR). The experimental results show that the average FWHM errors in the θ direction increased slightly from 0.94 mm to 1.14 mm when Δθ of the two single events was larger than 70°. The imaging performance of the MSR detector was also initially assessed with a Derenzo phantom filled with 18F-FDG. The rods with a diameter larger than 1.2 mm can be resolved. The energy resolutions were 12.3% at 511 keV (single events), and 11.4% at 1022 keV (coincidence events). We concluded that it is feasible to construct the high-performance preclinical PET scanners using one or multiple MSR detectors.
Subject(s)
Positron-Emission Tomography/instrumentation , Gamma Rays , Phantoms, Imaging , PhotonsABSTRACT
Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a novel approach for performing liver resection, and the number of clinical applications of this technique has rapidly increased within recent years. ALPPS is important in patients who have insufficient residual liver volume and cannot undergo radical hepatic resection. The most common postoperative complications of ALPPS include biliary fistula and infection. To date, postoperative acute kidney injury following ALPPS has not been reported. The current study reports the case of a 63-year-old patient with hepatitis B-induced cirrhosis who underwent the first stage of ALPPS without completion of the second step. The patient developed postoperative acute kidney injury following ALPPS. The present case study suggests that the use of ALPPS in patients at risk of chronic renal damage should be approached with caution in order to avoid postoperative acute kidney injury. Furthermore, improvements in surgical techniques and skills of the surgeons performing the procedure are required to reduce the surgery duration and improve patient outcomes.
ABSTRACT
RATIONALE: Gallbladder perforation is a relatively uncommon complication of alcoholic liver cirrhosis and may happen with or without gallstones. PATIENT CONCERNS: Here we report a 52-year-old male patient who was diagnosed as gallbladder perforation with chronic liver cirrhosis and asymptomatic gallstones. The patient was admitted with acute and severe abdominal pain during weight-bearing physical labor. He had a history of alcoholic liver cirrhosis but no chronic abdominal pain or gallstones. The patient presented with localized peritoneal irritation, and abdominal puncture showed non-clotting blood. A preliminary clinical diagnosis was made as hepatocellular carcinoma rupture based on imaging findings. However, this diagnosis changed to gangrenous cholecystitis with gallbladder perforation by the laparotomy examination. DIAGNOSES: He was diagnosed with gangrenous cholecystitis with gallbladder perforation. INTERVENTIONS AND OUTCOMES: The patient performed well postoperatively. LESSONS: This case suggests that gallbladder perforation should be considered as a potential cause of acute abdominal pain even without evidence of gallstones. Early examination with a laparotomy examination can help achieve a timely diagnosis.
Subject(s)
Asymptomatic Diseases , Cholecystitis/complications , Gallbladder/pathology , Gallstones/complications , Liver Cirrhosis, Alcoholic/complications , Spontaneous Perforation/etiology , Cholecystitis/surgery , Humans , Laparotomy/methods , Male , Middle Aged , Spontaneous Perforation/surgery , Tomography, X-Ray Computed , UltrasonographyABSTRACT
Increasing the image quality of positron emission tomography (PET) is an essential topic in the PET community. For instance, thin-pixelated crystals have been used to provide high spatial resolution images but at the cost of sensitivity and manufacture expense. In this paper, we proposed an approach to enhance the PET image resolution and noise property for PET scanners with large pixelated crystals. To address the problem of coarse blurred sinograms with large parallax errors associated with large crystals, we developed a data-driven, single-image super-resolution (SISR) method for sinograms, based on the novel deep residual convolutional neural network (CNN). Unlike the CNN-based SISR on natural images, periodically padded sinogram data and dedicated network architecture were used to make it more efficient for PET imaging. Moreover, we included the transfer learning scheme in the approach to process cases with poor labeling and small training data set. The approach was validated via analytically simulated data (with and without noise), Monte Carlo simulated data, and pre-clinical data. Using the proposed method, we could achieve comparable image resolution and better noise property with large crystals of bin sizes of thin crystals with a bin size from to . Our approach uses external PET data as the prior knowledge for training and does not require additional information during inference. Meanwhile, the method can be added into the normal PET imaging framework seamlessly, thus potentially finds its application in designing low-cost high-performance PET systems.
Subject(s)
Deep Learning , Image Processing, Computer-Assisted/methods , Positron-Emission Tomography/methods , Algorithms , Animals , Mice , Phantoms, ImagingABSTRACT
PURPOSE: In brain imaging, the spherical PET system achieves the highest sensitivity when the solid angle is concerned. However, it is not practical. In this work, we designed an alternative sphere-like scanner, the dodecahedral scanner, which has a high sensitivity in imaging and a high feasibility to manufacture. We simulated this system and compared the performance with a few other dedicated brain PET systems. METHODS: Monte Carlo simulations were conducted to generate data of the dedicated brain PET system with the dodecahedral geometry (11 regular pentagon detectors). The data were then reconstructed using the in-house developed software with the fully three-dimensional maximum-likelihood expectation maximization (3D-MLEM) algorithm. RESULTS: Results show that the proposed system has a high-sensitivity distribution for the whole field of view (FOV). With a depth-of-interaction (DOI) resolution around 6.67 mm, the proposed system achieves the spatial resolution of 1.98 mm. Our simulation study also shows that the proposed system improves the image contrast and reduces noise compared with a few other dedicated brain PET systems. Finally, simulations with the Hoffman phantom show the potential application of the proposed system in clinical applications. CONCLUSIONS: In conclusion, the proposed dodecahedral PET system is potential for widespread applications in high-sensitivity, high-resolution PET imaging, to lower the injected dose.
Subject(s)
Brain/diagnostic imaging , Computer Simulation , Positron-Emission Tomography/instrumentation , Algorithms , Brain/metabolism , Equipment Design , Humans , Likelihood Functions , Monte Carlo Method , Phantoms, Imaging , Radiation Dosage , Software , WaterABSTRACT
This work modified the commonly used Monte Carlo tool package GATE by developing a new 'multiPatchPET' system so that GATE users can easily simulate PET systems with irregular geometries. The motivation was to design a brain PET scanner with high sensitivity. It is known that compact PET scanners with a large solid coverage angle can achieve high sensitivity with fewer scintillation detectors, and thus have the potential to provide better image quality in brain PET imaging than conventional ring PET scanners. However, considering a straightforward example with the largest possible solid angle, a spherical PET scanner is hard to manufacture. A more practical alternative would be a sphere-like polyhedral PET scanner with flat detector patches. Moreover, when monolithic scintillators are chosen to construct these flat detector modules, detection efficiency is further improved. Thus, we plan to design a sphere-like polyhedral PET scanner made up of monolithic scintillators. Unfortunately, in our design study, we found that simulating such a scanner with the latest GATE version (8.0) was not trivial, since no predefined systems could be used. In this work we introduced a 'multiPatchPET' system to GATE, which we and other GATE users will be able to use to develop PET scanners with any irregular geometry and any shape of patch. To validate our modification, a single block detector and an mCT scanner were simulated via both the original 'ecat' system and the new 'multiPatchPET' system. The results show no difference in terms of the detecting efficiency and reconstruction image. Then we used the 'multiPatchPET' system to simulate an 86 surface polyhedral brain PET scanner. Compared with two cylindrical brain scanners, the polyhedral brain scanner shows a higher sensitivity and has fewer noisy images. Thus, it was proved that our modification, which is accessible to the nuclear imaging research community, equipped GATE with a powerful and user-friendly tool to simulate complex scanners with irregular patches easily.