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Assessing the Impact of Regulations on Radiation Safety Culture and Practices in Radiology Departments
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作者 Saad Alqahtani Khaled Soliman +8 位作者 Khaled Altuwayjiri Mohammed Al Shehri Yahya Jubran Alwaleed Al Hussein Nawaf Alanazi Nawaf Alanazi Fahad Alqarni Hela Alqahtani Ahmed Jowana 《Journal of Applied Mathematics and Physics》 2024年第8期3006-3016,共11页
Background: The need to establish a strong culture around radiation safety is derived from the assertion that medical practitioners, patients, and third parties should not be exposed to unnecessary radiation. Authorit... Background: The need to establish a strong culture around radiation safety is derived from the assertion that medical practitioners, patients, and third parties should not be exposed to unnecessary radiation. Authorities have endeavored to enact policies to protect all employers and patients in radiology departments. Objectives: To assess the impact of radiation safety practices and regulations on the ongoing improvements in radiation safety culture and practices in radiology departments. This will be achieved through a subjective assessment of national and international rules and regulations by healthcare professionals. Materials and Methods: We conducted a questionnaire survey in the radiology departments of three JCI-accredited hospitals in the Riyadh region to identify and assess the impact of national radiation regulations and the accompanying processes on the improvement of radiation safety culture and practices in radiology departments. Results: There were statistically significant differences in the grading system results among various groups of respondents, based on their educational level. Also, there are statistically significant differences between the assessments of safety level results in the answers provided by various groups of respondents according to education level in favor of the master’s degree. Conclusion: The study concludes that technicians with a diploma degree require stricter regulation. Furthermore, the results of this study suggest that an exposure tracking system and a regulatory action supporting it may be useful in the ongoing task of improving patients’ radiation safety. 展开更多
关键词 Impact Radiation Safety Culture REGULATIONS ACCREDITATION Practice Radiology Departments
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Erratum to “Novel Wavelet-Based Segmentation of Prostate CBCT Images with Implanted Calypso Transponders” [International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 6 (2017) 336-343]
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作者 Yingxia Liu Ziad Saleh +5 位作者 Yulin Song Maria Chan Xiang Li Chengyu Shi Xin Qian Xiaoli Tang 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2017年第4期376-376,共1页
The original online version of this article (Liu, Y.X., Saleh, Z., Song, Y.L., Chan, M., Li, X., Shi, C.Y., Qian, X. and Tang, X.L (2017) Novel Wavelet-Based Segmentation of Prostate CBCT Images with Implanted Calypso... The original online version of this article (Liu, Y.X., Saleh, Z., Song, Y.L., Chan, M., Li, X., Shi, C.Y., Qian, X. and Tang, X.L (2017) Novel Wavelet-Based Segmentation of Prostate CBCT Images with Implanted Calypso Transponders. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 6, 336-343. doi: 10.4236/ijmpcero.2017.63030) was published without acknowledging our support. The authors wish to add the acknowledgments. 展开更多
关键词 Erratum
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Life Time Attributable Cancer Risk Estimated Using Scanner Reported Dose Length Product during Chest Computed Tomography Imaging in Young Children
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作者 Mousa Bakkari Khaled Soliman +3 位作者 Abdullah Alrushoud Marwan Fahad Alosaimi Hanaa Alsheikh Abdelwahed Alhejaili 《Open Journal of Radiology》 2024年第2期74-82,共9页
This study aims to estimate the lifetime attributable cancer risk (LAR) for pediatric chest computed tomography (CT) examinations in five age groups using recently published age and region-specific conversion coeffici... This study aims to estimate the lifetime attributable cancer risk (LAR) for pediatric chest computed tomography (CT) examinations in five age groups using recently published age and region-specific conversion coefficients multiplying the widely available scanner registered dose length products (DLP) displayed on the CT console and hence calculating the Effective Dose (ED). The ED is then multiplied by the International Commission on Radiological Protection (ICRP) published risk factor for LAR. The obtained LAR values are compared with the international literature. Factors that may affect the LAR value are reported and discussed. The study included one hundred twenty five chest CT examinations for both males and females aged from less than one year to fifteen years. The patients reported data are from one single medical institution and using two CT scanners from June 2022 to December 2023. The results of this study may serve as benchmark for institutional radiation dose reference levels and risk estimation. 展开更多
关键词 Cancer Risk LAR Chest CT Pediatric Radiology Radiation Dose DLP
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Planning Target Volume Margin in Linac-Based Stereotactic Radiosurgery for Brain Metastases
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作者 Hany S. Attallah Radwa M. Hamed +5 位作者 Khaled M. EL-Shahat Aliaa Mahmoud Mahmoud Abdallah Ibraheem Haggag Emad Moustafa Adel Yassin 《Journal of Cancer Therapy》 2024年第7期265-272,共8页
Background: The treatment of brain metastases with radiotherapy has shifted to the use of Stereotactic Radio-surgery (SRS). The technical issue of expanding the treatment volume around the Gross Tumor Volume (GTV) is ... Background: The treatment of brain metastases with radiotherapy has shifted to the use of Stereotactic Radio-surgery (SRS). The technical issue of expanding the treatment volume around the Gross Tumor Volume (GTV) is a current debate. Radiotherapy centers use variable GTV-PTV margins, ranging from one to 2 mm. Material and Methods: We performed a dosimetric comparison in plans of twenty patients using three margins: PTV zero, PTV1, and PTV2. We also developed imaginary Peel volumes. These volumes are described as follows: Peel1 = PTV1 − GTV, Peel2 = PTV2 − GTV. Results: Our results showed that the mean PTV volume differed significantly across the different margins (p = 0.000). The V12 of the brain significantly varied as a function of PTV margin (p = 0.000). The target coverage and plan quality indices were not significantly different. The Peel volume dosimetric analysis showed that the mean dose was significantly higher in the nearby normal brain tissue: Peel1 (p = 0.022) and Peel 2 (p = 0.013). Conclusion: According to our dosimetric analysis, expanding the GTV into a PTV by 1 mm margin is more convenient than 2 mm. 展开更多
关键词 SRS Brain Metastases PTV
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Variability in Fluoroscopic Time during Interventional Non-Cardiac Procedures Performed Outside of the Radiology Department
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作者 Murdhi A. Al Harbi Abdullah H. Al Malki +1 位作者 Saeed A. Al Ahmari Khaled Soliman 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2018年第4期464-471,共8页
Purpose: Increasing physician awareness of patient exposure to radiation is an important step towards the reduction of potentially harmful effects of radiation. Published studies demonstrated that providing physicians... Purpose: Increasing physician awareness of patient exposure to radiation is an important step towards the reduction of potentially harmful effects of radiation. Published studies demonstrated that providing physicians with feedback regarding their fluoroscopy time leads to a reduction in average fluoroscopy times. The aim of this work was to analyze and publish our medical center data observed during the past year;fluoroscopy time (FT), Dose Area Product (DAP) and cumulative dose (CD) were monitored for radiation protection purposes. Methods: Fluoroscopy time is one of multiple radiation dose indices used in radiation safety auditing. Such auditing is nowadays turning into requirement of patient care safety and quality improvement;as indicated by accreditation bodies both nationally and internationally. All non-cardiac procedures performed outside radiology department by surgeons and interventionists are viewed. FT, DAP and CD are extracted for analysis. Results: a total of 846 cases were studied (643 orthopedic, 99 others, 73 urology, 17 chest, 7 vascular and 4 ERCP cases). Mean FT was 1.3 minutes, mean CD to the patient was 12.98 mGy and the mean DAP was 4.53 Gy/cm2. The longest FT noted was 55 min. The maximum CD was 904 mGy and the maximum DAP was 689 Gy/cm2. Using spearman’s correlation test we found out that there is a significant correlation between FT and DAP (correlation coefficient = 0.615, p. value 0.001). There is a significant correlation between FT and CD (correlation coefficient = 0.628, p. value 0.001). Conclusion: Information about FT that used in each procedure can be used as a tool for patient dose optimization. As we found a significant correlation between DAP as well as CD. Reducing fluoroscopic time (FT) is a radiation protection goal, since it serves the purpose of protection for both the patient and the workers. 展开更多
关键词 FLUOROSCOPY TIME INTERVENTIONAL RADIOLOGY Cumulative DOSE DOSE Area Product
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Review of deep learning and artificial intelligence models in fetal brain magnetic resonance imaging 被引量:1
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作者 Farzan Vahedifard Jubril O Adepoju +5 位作者 Mark Supanich Hua Asher Ai Xuchu Liu Mehmet Kocak Kranthi K Marathu Sharon E Byrd 《World Journal of Clinical Cases》 SCIE 2023年第16期3725-3735,共11页
Central nervous system abnormalities in fetuses are fairly common,happening in 0.1%to 0.2%of live births and in 3%to 6%of stillbirths.So initial detection and categorization of fetal Brain abnormalities are critical.M... Central nervous system abnormalities in fetuses are fairly common,happening in 0.1%to 0.2%of live births and in 3%to 6%of stillbirths.So initial detection and categorization of fetal Brain abnormalities are critical.Manually detecting and segmenting fetal brain magnetic resonance imaging(MRI)could be timeconsuming,and susceptible to interpreter experience.Artificial intelligence(AI)algorithms and machine learning approaches have a high potential for assisting in the early detection of these problems,improving the diagnosis process and follow-up procedures.The use of AI and machine learning techniques in fetal brain MRI was the subject of this narrative review paper.Using AI,anatomic fetal brain MRI processing has investigated models to predict specific landmarks and segmentation automatically.All gestation age weeks(17-38 wk)and different AI models(mainly Convolutional Neural Network and U-Net)have been used.Some models'accuracy achieved 95%and more.AI could help preprocess and postprocess fetal images and reconstruct images.Also,AI can be used for gestational age prediction(with one-week accuracy),fetal brain extraction,fetal brain segmentation,and placenta detection.Some fetal brain linear measurements,such as Cerebral and Bone Biparietal Diameter,have been suggested.Classification of brain pathology was studied using diagonal quadratic discriminates analysis,Knearest neighbor,random forest,naive Bayes,and radial basis function neural network classifiers.Deep learning methods will become more powerful as more large-scale,labeled datasets become available.Having shared fetal brain MRI datasets is crucial because there aren not many fetal brain pictures available.Also,physicians should be aware of AI's function in fetal brain MRI,particularly neuroradiologists,general radiologists,and perinatologists. 展开更多
关键词 Artificial intelligence Fetal brain Magnetic resonance imaging NEUROIMAGING
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Analysis of Local Diagnostic Reference Levels for Pediatric Patients Undergoing 18F-FDG PET/CT Imaging for Oncology
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作者 Saad Alqahtani Khaled Soliman +5 位作者 Saad Alotaibi Khaled Alnofaie Abdullah Alahmari Fahad Alyahya Abdullah Albdullah Rashed Alharbi 《Journal of Applied Mathematics and Physics》 2023年第7期2144-2155,共12页
Background: The PET/CT imaging studies have two doses components the dose from the PET radiopharmaceutical and the other from the low dose CT used for PET images attenuation correction. We have one PET/CT scanner at o... Background: The PET/CT imaging studies have two doses components the dose from the PET radiopharmaceutical and the other from the low dose CT used for PET images attenuation correction. We have one PET/CT scanner at our institution a Philips Time of Flight scanner. Our local patient’s radiation protection rules requires continuous assessment of radiation doses delivered to our patients. Purposes: The objectives of this study are to develop a weight- based facility DRLs for paediatric F-18-FDG PET-CT imaging for oncology in a large tertiary hospital and to determine whether the calculated DRLs compares with internationally published DRLs. Materials & Methods: Radiation dose data and patient demographics of two-hundreds and sixteen paediatric PET-CT oncology patients imaging procedures from one large tertiary hospital were selected and analysed in order to establish a facility paediatric DRLs. Statistical analysis was performed. Results: The PET dose reference levels ranged between [62 - 525] MBq of injected activity for a range of pediatric age groups. The CTDI<sub>vol</sub> values were between 3.5 and 16.5 mGy for all age groups. Comparison with current EANM and SNMMI recommendations of patient’s dose are discussed. Conclusion: Our pediatric PET/CT reference levels are higher than the ones reported internationally with notable variations. . 展开更多
关键词 Diagnostic Reference Levels PET/CT 18-F-FDG Pediatric Radiation Dose CTDIvol ONCOLOGY
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Radiation Dose Survey of Pediatric Chest Computed Tomography Examinations: A Local Diagnostic Reference Levels Approach to Patient Safety
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作者 Turki Alruwaili Bani Alsubaie +1 位作者 Salman Altimyat Khaled Soliman 《Journal of Applied Mathematics and Physics》 2023年第7期2137-2143,共7页
Objectives: The aim of this work was to initially establish both age and weight driven pediatric diagnostic reference levels (DRLs) for chest computed tomography (CT) examinations performed at tertiary care medical in... Objectives: The aim of this work was to initially establish both age and weight driven pediatric diagnostic reference levels (DRLs) for chest computed tomography (CT) examinations performed at tertiary care medical institution. Another aim was to compare the presented data with internationally published ones. This initial data shall serve as basis for establishing a national DRLs values for pediatric diagnostic CT examinations. Methods: Dosimetric indexes were collected for the chest examination for 93 patients during the past 2 years in a tertiary care medical city. Results: The results are within and below the international reported levels for chest CT in several countries. Conclusion: Continuous monitoring of the radiation doses received by the patients in computed tomography is continuous and ongoing process in order to ensure compliance and to optimize clinical imaging protocols. More extensive data acquisition and analysis are required to allow better understanding of the contributing factors leading to less patient radiation dose while preserving the clinical image quality. . 展开更多
关键词 Computed Tomography Chest CT Diagnostic Reference Levels Monitoring Optimization
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Relationship between Whole Body Iodine-131 Effective Half-Life and Estimated Glomerular Filtration Rate for Papillary Thyroid Cancer Patients Undergoing Radioactive Iodine Therapy
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作者 Asim Abualnaja Hanaa Alsheikh +2 位作者 Khaled Soliman Meshal Alnefaie Abdulraheem Alsheri 《Journal of Applied Mathematics and Physics》 2023年第8期2472-2479,共8页
Background: The aim of this work was to examine the relationship between the estimated glomerular filtration rate (eGFR) as indicator of renal efficiency potentially related to the ability to release radioactive iodin... Background: The aim of this work was to examine the relationship between the estimated glomerular filtration rate (eGFR) as indicator of renal efficiency potentially related to the ability to release radioactive iodine from the patients bodies and the radioactive iodine whole body effective half-life (WBEHL) defined as the time taken for the administered activity to decay to half of its value for papillary thyroid cancer (PTC) patients undergoing radioactive iodine therapy (RAIT) in a tertiary care medical Centre. Methods: This retrospective observational study included seventy nine patients, sixty females and nineteen males. The patients were divided in two subgroups, those who have WBEHL of less than 11 hours (n = 51) and those with more than 11 (n = 28) hrs based on k-means clustering technique. Results: Analysis of variance (ANOVA) was used to find out if there is a statistically significant difference between the two subgroups Conclusion: There was not a statistically significant difference between the short and the longer WBEHL patients’ groups analyzed in this study. . 展开更多
关键词 GFR Thyroid Cancer Radioactive Iodine Therapy Renal Function
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Quality Assuring a Ring Vortex Flow Phantom in Real-Time
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作者 Alana S. Matthews Kelvin Simatwo +3 位作者 Andrew Narracott Simone Ambrogio Adrian Walker John W. Fenner 《Open Journal of Medical Imaging》 2023年第1期11-29,共19页
Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstra... Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities. 展开更多
关键词 Flow Phantom Ring Vortex Quality Assurance IMAGING
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Wireless capsule endoscopy in the investigation of patients with chronic renal failure and obscure gastrointestinal bleeding (preliminary data) 被引量:8
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作者 Stephanos Karagiannis Spyros Goulas +5 位作者 Georgios Kosmadakis Petros Galanis Dimitrios Arvanitis John Boletis Evangelos Georgiou Christos Mavrogiannis 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第32期5182-5185,共4页
AIM: To investigate the role of wireless capsule endoscopy (WCE) in detection of small bowel (SB) pathology in patients with chronic renal failure (CRF) and obscure bleeding. METHODS: Consecutive CRF patients ... AIM: To investigate the role of wireless capsule endoscopy (WCE) in detection of small bowel (SB) pathology in patients with chronic renal failure (CRF) and obscure bleeding. METHODS: Consecutive CRF patients with obscure bleeding were prospectively studied. Patients with normal renal function and obscure bleeding, investigated during the same period with WCE, were used for the interpretation of results. RESULTS: Seventeen CRF patients (11 overt, 6 occult bleeding) and 51 patients (33 overt, 18 occult bleeding) with normal renal function were enrolled in this study. Positive SB findings were detected in 70.6% of CRF patients and in 41.2% of non-CRF patients (P〈0.05). SB angiodysplasia was identified in 47% of CRF patients and in 17.6% of non-CRF patients. Univariate logistic regression revealed CRF as a significant predictive factor for angiodysplasia (P〈0.05). Therapeutic measures were undertaken in 66% of the patients with the positive findings. CONCLUSION: According to our preliminary results, SB angiodysplasia was found in an increased prevalence among CRF patients with obscure bleeding. WCE is useful in diagnosis of gastrointestinal pathologies and in planning appropriate therapeutic intervention and, therefore, should be included in the work-up of this group of patients. 展开更多
关键词 Chronic renal failure Obscure gastrointestinalbleeding Wireless capsule endoscopy ANGIODYSPLASIA
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Clinical decision support systems for brain tumor characterization using advanced magnetic resonance imaging techniques 被引量:2
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作者 Evangelia Tsolaki Evanthia Kousi +4 位作者 Patricia Svolos Efthychia Kapsalaki Kyriaki Theodorou Constastine Kappas Ioannis Tsougos 《World Journal of Radiology》 CAS 2014年第4期72-81,共10页
In recent years, advanced magnetic resonance imaging(MRI) techniques, such as magnetic resonance spec-troscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in ord... In recent years, advanced magnetic resonance imaging(MRI) techniques, such as magnetic resonance spec-troscopy, diffusion weighted imaging, diffusion tensor imaging and perfusion weighted imaging have been used in order to resolve demanding diagnostic prob-lems such as brain tumor characterization and grading, as these techniques offer a more detailed and non-invasive evaluation of the area under study. In the last decade a great effort has been made to import and utilize intelligent systems in the so-called clinical deci-sion support systems(CDSS) for automatic processing, classification, evaluation and representation of MRI data in order for advanced MRI techniques to become a part of the clinical routine, since the amount of data from the aforementioned techniques has gradually inticle is two-fold. The first is to review and evaluate the progress that has been made towards the utilization of CDSS based on data from advanced MRI techniques. The second is to analyze and propose the future work that has to be done, based on the existing problems and challenges, especially taking into account the new imaging techniques and parameters that can be intro-duced into intelligent systems to significantly improve their diagnostic specificity and clinical application. 展开更多
关键词 Decision support systems MAGNETIC reso-nance IMAGING MAGNETIC resonance spectroscopy DIFFUSION WEIGHTED IMAGING DIFFUSION tensor IMAGING PERFUSION WEIGHTED IMAGING Pattern recognition
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Mutifactorial analysis of risk factors for reduced bone mineral density in patients with Crohn’s disease 被引量:2
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作者 Sarah A Bartram Robert T Peaston +3 位作者 David J Rawlings David Walshaw Roger M Francis Nick P Thompson 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第35期5680-5686,共7页
AIM: To determine the prevalence of osteoporosis in a cohort of patients with Crohn’s disease (CD) and to identify the relative significance of risk factors for osteoporosis. METHODS: Two hundred and fifty-eight unse... AIM: To determine the prevalence of osteoporosis in a cohort of patients with Crohn’s disease (CD) and to identify the relative significance of risk factors for osteoporosis. METHODS: Two hundred and fifty-eight unselected patients (92 M, 166 F) with CD were studied. Bone mineral density (BMD) was measured at the lumbar spine and hip by dual X-ray absorptiometry. Bone formation was assessed by measuring bone specific alkaline phosphatase (BSAP) and bone resorption by measuring urinary excretion of deoxypyridinoline (DPD) and N-telopeptide (NTX). RESULTS: Between 11.6%-13.6% patients were osteoporotic (T score < -2.5) at the lumbar spine and/or hip. NTX levels were significantly higher in the patients with osteoporosis (P < 0.05) but BSAP and DPD levels were not significantly different. Independent risk factors for osteoporosis at either the lumbar spine or hip were a low body mass index (P < 0.001), increasing corticosteroid use (P < 0.005), and male sex (P < 0.01). These factors combined accounted for 23% and 37% of the reduction in BMD at the lumbar spine and hip respectively. CONCLUSION: Our results confirm that osteoporosis is common in patients with CD and suggest that increased bone resorption is the mechanism responsible for thebone loss. However, less than half of the reduction in BMD can be attributed to risk factors such as corticosteroid use and low BMI and therefore remains unexplained. 展开更多
关键词 Crohn's disease OSTEOPOROSIS OSTEOPENIA Bone mineral density
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The Heat Shock Protein Story—From Taking mTORC1,2 and Heat Shock Protein Inhibitors as Therapeutic Measures for Treating Cancers to Development of Cancer Vaccines 被引量:3
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作者 Peter Chin Wan Fung Regina Kit Chee Kong 《Journal of Cancer Therapy》 2017年第11期962-1029,共68页
Heat shock proteins (HSPs) serve to correct proteins’ conformation, send the damaged proteins for degradation (quality control function). Heat shock factors (HSFs) are their transcription factors. The protein complex... Heat shock proteins (HSPs) serve to correct proteins’ conformation, send the damaged proteins for degradation (quality control function). Heat shock factors (HSFs) are their transcription factors. The protein complexes mTOR1 and 2 (with the same core mTOR), the phosphoinositide-dependent protein kinase-1 (PDK1), the seine/threonine-specific protein kinase (Akt), HSF1, plus their associated proteins form a network participating in protein synthesis, bio-energy generation, signaling for apoptosis with the help of HSPs. A cancer cell synthesizes proteins at fast rate and needs more HSPs to work on quality control. Shutting down this network would lead to cell death. Thus inhibitors of mTOR (mTORI) and inhibitors of HSPs (HSPI) could drive cancer cell to apoptosis—a “passive approach”. On the other hand, HSPs form complexes with polypeptides characteristic of the cancer cells;on excretion from the cell, they becomes antigens for the immunity cells, eventually leading to maturation of the cytotoxic T cells, forming the basic principle of preparing cancer-specific, person-specific vaccine. Recent finding shows that HSP70 can penetrate cancer cell and expel its analog to extracellular region, giving the hope to prepare a non-person-specific vaccine covering a variety of cancers. Activation of anti-cancer immunity is the “active approach”. On the other hand, mild hyperthermia, with increase of intracellular HSPs, has been found to activate the immunity response, and demonstrate anti-cancer effects. There are certain “mysteries” behind the mechanisms of the active and passive approaches. We analyze the mechanisms involved and provide explanations to some mysteries. We also suggest future research to improve our understanding of these two approaches, in which HSPs play many roles. 展开更多
关键词 HEAT Shock Proteins and HEAT Shock Factors mTORC1 2 Complexes Mild Hyperthermia ANTI-CANCER Drugs and HSP-Based ANTI-CANCER Vaccine Immunity Cells Trafficking through High Endothelial VENULES of Cancer Site Intrinsic Extrinsic FOXO Translocation and the PERK-CHOP Apoptotic Pathways TYROSINE Kinase Receptors
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Leakage-Penumbra effect in intensity modulated radiation therapy step-and-shoot dose delivery 被引量:1
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作者 Grigor N Grigorov James CL Chow 《World Journal of Radiology》 CAS 2016年第1期73-81,共9页
AIM: To study the leakage-penumbra(LP) effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS: Leakage-penumbra dose profiles from 10 randomly selected pros... AIM: To study the leakage-penumbra(LP) effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS: Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied. The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC). For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated. For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV). The overshoot effect(OSE) and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V) radiographic films. Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16). The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations. RESULTS: A non-uniformly distributed leaf LP dose ranging from 3% to 5% of the beam dose was measured in clinical IMRT beams. An overdose at the gap between neighboring segments,represented as dose peaks of up to 10% of the total BP,was measured. The LP effect increased the dose to the PTV and surrounding critical tissues. In addition,the effectdepends on the number of beams and segments for each beam. Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans. The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection. As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams. CONCLUSION: We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected. 展开更多
关键词 Multileaf COLLIMATOR LEAKAGE OVERSHOOT EFFECT Beam PENUMBRA PROSTATE intensity modulated radiation therapy planning
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Phase-sensitive fat suppression steady-state free procession sequence with phase correction 被引量:1
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作者 俎中良 周堃 +2 位作者 张仕刚 高篙 包尚联 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第1期328-334,共7页
Robust and fast fat suppression is a challenge in balanced steady-state free precession (SSFP) magnetic resonance imaging. Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short ... Robust and fast fat suppression is a challenge in balanced steady-state free precession (SSFP) magnetic resonance imaging. Although single-acquisition phase-sensitive SSFP can provide fat-suppressed images in short scan time, phase errors, especially spatially-dependent phase shift, caused by a variety of factors may result in misplacement of fat and water voxels. In this paper, a novel phase correction algorithm was used to calibrate those phase errors during image reconstruction. This algorithm corrects phase by region growing, employing both the magnitude and the phase information of image pixels. Phantom and in vivo imagings were performed to validate the technique. As a result, excellent fat-suppressed images were acquired by using single-acquisition phase-sensitive SSFP with phase correction. 展开更多
关键词 steady-state free precession fat suppression phase-sensitive phase correction
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The Integrative Five-Fluid Circulation System in the Human Body 被引量:7
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作者 Peter Chin Wan Fung Regina Kit Chee Kong 《Open Journal of Molecular and Integrative Physiology》 2016年第4期45-97,共53页
Water is the key medium to transport numerous constituents and to provide a platform for physiological processes to take place in the living organisms in general;it also participates actively in many of these processe... Water is the key medium to transport numerous constituents and to provide a platform for physiological processes to take place in the living organisms in general;it also participates actively in many of these processes. In humans, there are different vehicles to contain water and its constituents. Our objective is to find out whether there is an overall water-base circulation system in the human body by analyzing the updated findings of different research groups on the physiological functions of various seemingly isolated fluid systems. By 1963, there were five separate fluid systems discovered in mammalians: (i) The Primo Vasculature Fluid (PVF) with protein precursors and micro cells held in the Primo Vasculature System (PVS). (ii) Blood with its constituents held in the cardio vasculature. (iii) Extracranial interstitial fluid (ISF) whose vehicle had a very irregular structure—the interstitium all over the body. (iv) The cerebrospinal fluid had been considered to be within the brain ventricles and spinal canal. (v) The extra-cranial lymphatic system which drained ISF, and had been known to join the subclavian vein. Fluid (i) was first reported in 1963 and fluids (ii) to (v) have been known for many decades, but the failure to detect a lymphatic system inside the skull has also been a mystery for many decades. The intra-cranial ISF (which we name as BISF) has drawn little attention, apart from discussing the mechanism of the blood-brain-barrier. During the past decade, there has been direct evidence indicating that CSF and BISF are actually mixed. After that, the intracranial lymphatic system was discovered and confirmed in animal models only slightly over one year back, and we called such fluid as glymphatic-fluid. After reviewing the stated “classical” five fluid systems together with the new findings in Sections 2 - 7, we propose, for the first time, that the PVF, the blood, ISF, a mixture of CSF-BISF, and a mixture of glymphatic-fluid and lymph form an integrative circulation system in water base in the human and other mammalian bodies, as schematically represented in the last section. In this paper, we point out the positive correlation of chronic neuro degenerative diseases such as Alzheimer’s disease, Parkinson’s diseases and the insufficient brain wastes clearance by the glymphatic system. We also discuss the role played by the venous vessels as part of such clearance in upright posture. Moreover, simple non-invasive maneuver techniques are introduced here, as one example of enhancement of glymphatic fluid flow out of the skull to join the lymphatic system. A series of questions are raised in Section 8, the answers to which would help us to understand the transition from physio- to pathological states in the development of many diseases. Detailed analysis of this paper leads us to consider that research in understanding this integrative circulation system is only at the infancy stage, and fluid dynamics investigation seems to be the plausible modality of approach in the near future. 展开更多
关键词 Glymphatic System Primo Vasculature System Cerebrospinal Fluid Intra-Cranial and Extra-Cranial Interstitial Fluids Lymph Cardiovascular System Integrative Five-Fluid Circulation System Neuro Degenerative Diseases
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Dose Perturbations of Gold Fiducial Markers in the Prostate Cancer Intensity Modulated Proton Radiation Therapy (IMPT) 被引量:1
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作者 Miao Zhang Sung Kim +3 位作者 Ting Chen Xiaohu Mo Bruce G. Haffty Ning J. Yue 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2012年第1期8-13,共6页
The objective of this study is to investigate the dose perturbations introduced by the implanted gold fiducial markers in the prostate cancer intensity modulated proton therapy (IMPT) and the impacts of different plan... The objective of this study is to investigate the dose perturbations introduced by the implanted gold fiducial markers in the prostate cancer intensity modulated proton therapy (IMPT) and the impacts of different plan designs on the pertur-bations. Five proton plans: a single lateral field 3D-modulation (3D-mod) plan, 2 fields laterally opposing 3D-mod plan, 6-, 9-, and 18-field distal edge tracking (DET) plans were designed on the CT images of a prostate patient. The dose distributions were first generated for the plans free of fiducial markers with 78 Gy prescribed to 95% of the PTV. To derive the dose perturbations of the gold fiducial markers, three cylindrical shaped gold fiducial markers (3 mm long and 1 mm in diameter) were artificially inserted into the prostate, and the dose distributions were re-computed. Monte Carlo method was used for dose computation. It was found that the gold fiducial markers perturbed the dose distribu-tions, especially along the beam paths. The markers caused a shadowing effect reducing the doses in the areas beyond the markers. Overall, due to the presence of the fiducial markers, D99% of prostate were reduced by 2.96 Gy, 4.21 Gy, 0.16 Gy, 0.34 Gy, 0.15 Gy for the plans of single field 3D-mod, 2-field parallel opposed 3D-mod, 6-, 9-, and 18-field DET respectively. Our study showed these dose perturbation effects decreased with the increase of number of beam angles. Up to 6 beam angles may be required to reduce the dose perturbations from the gold fiducial markers to a clini- cally acceptable level in IMPT. 展开更多
关键词 GOLD Fiducial MARKER Intensity Modulated PROTON Therapy PROSTATE Cancer Monte Carlo
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Scientometric Implosion that Leads to Explosion: Case Study of Armenian Journals 被引量:1
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作者 Shushanik Sargsyan Edita Gzoyan +1 位作者 Aram Mirzoyan Viktor Blaginin 《Journal of Data and Information Science》 CSCD 2020年第3期187-196,共10页
Purpose: The purpose of this study is to introduce a new concept and term into the scientometric discourse and research—scientometric implosion—and test the idea on the example of the Armenian journals. The article ... Purpose: The purpose of this study is to introduce a new concept and term into the scientometric discourse and research—scientometric implosion—and test the idea on the example of the Armenian journals. The article argues that the existence of a compressed scientific area in the country makes pressure on the journals and after some time this pressure makes one or several journals explode—break the limited national scientific area and move to the international arena. As soon as one of the local journals breaks through this compressed space and appears at an international level, further explosion happens, which makes the other journals follow the same path.Design/methodology/approach: Our research is based on three international scientific databases—WoS, Scopus, and RISC CC, from where we have retrieved information about the Armenian journals indexed there and citations received by those journals and one national database—the Armenian Science Citation Index. Armenian Journal Impact Factor(ArmJIF) was calculated for the local Armenian journals based on the general impact factor formula. Journals were classified according to Gl?nzel and Schubert(2003). Findings: Our results show that the science policy developed by the scientific authorities of Armenia and the introduction of ArmJIF have made the Armenian journals comply with international standards and resulted in some local journals to break the national scientific territory and be indexed in international scientific databases of RISC, Scopus, and WoS. Apart from complying with technical requirements, the journals start publishing articles also in foreign languages. Although nearly half of the local journals are in the fields of social sciences and humanities, only one journal from that field is indexed in international scientific databases. Research limitation: One of the limitations of the study is that it was performed on the example of only one state and the second one is that more time passage is needed to firmly evaluate the results. However, the introduction of the concept can inspire other similar case study. Practical implications: The new term and relevant model offered in the article can practically be used for the development of national journals.Originality/value: The article proposes a new term and a concept in scientometrics. 展开更多
关键词 Sceintometric implosion Armenian Journal Impact Factor(ArmJIF) National scientific databases Armenian Science Citation Index(ASCI) International scientific databases
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Applicability of Lung Equivalent Phantom Using the Cork with Absorbed Water in Radiotherapeutic Dosimetry 被引量:1
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作者 Hiraku Fuse Tatsuya Fujisaki +1 位作者 Ryutaro Ikeda Zen Hakani 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2018年第1期27-34,共8页
The radiation dosimetry in medical practice requires special phantom to simulate the organs and tissues of a human body. To achieve the same elemental composition as that of the human lung by weight percent, we constr... The radiation dosimetry in medical practice requires special phantom to simulate the organs and tissues of a human body. To achieve the same elemental composition as that of the human lung by weight percent, we constructed lung equivalent phantom (LEP) using cork with absorbed water in order for it to uniformly absorb the water. Then, we presented the physical properties and dosimetric characteristics of other commercial phantoms and the LEP. We found that the physical properties and dosimetric characteristics of the LEP were approximately the same as those of human lung tissue. LEP constitutes a new dosimetry tool because it can provide the dose distributions and point doses similar to those for the body with respiratory motion of lung. 展开更多
关键词 CORK LUNG EQUIVALENT PHANTOM Respiratory Motion DOSIMETRY
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