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Gunnar Sandbaek - One of the best experts on this subject based on the ideXlab platform.
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changes in dose area product entrance surface dose and lens dose to the radiologist in a vascular interventional laboratory when an old X Ray System is eXchanged with a new System
2011Co-Authors: Kristin Jensen, Livia Zangani, Anne Catrine Traegde Martinsen, Gunnar SandbaekAbstract:The aim of this study was to compare dose-area product (DAP), entrance surface dose (ESD), and lens dose to radiologists for an old and a new X-Ray System in a vascular interventional laboratory. DAP, ESD, fluoroscopy time, number of images, and patient weight were recorded for patients undergoing the following four procedures: percutaneous transluminal angioplasty (PTA) and stenting (divided into two subgroups, lower eXtremities and pelvis), nephrostomy, and treatment for varicocele. Halfway through the registration period, the 9-year-old X-Ray equipment was eXchanged with a new System. Lens doses to the radiologist were measured. There was a reduction in DAP for all procedures: PTA lower eXtremities 31% (12–8 Gy cm2), PTA/stenting pelvis 67% (134–44 Gy cm2), nephrostomy 39% (7–4 Gy cm2), and varicocele 70% (37–11 Gy cm2). The reduction in number of images was 17% (158–131), 23% (153–118), 68% (2–1), and 31% (50–35), eXplaining a part of the dose reduction. The reduction in ESD was 33, 60, 38, and 46%. The differences in measured lens doses indicate a dose reduction in three procedures (19–53%) and an increase in one (56%), but differences are not statistically significant. DAP and ESD from the X-Ray System were reduced for all procedures. The reduction was greater in the more radiation-demanding procedures.
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changes in dose area product entrance surface dose and lens dose to the radiologist in a vascular interventional laboratory when an old X Ray System is eXchanged with a new System
2011Co-Authors: Kristi Jense, Livia Zangani, Gunnar Sandbaek, Anne Catrine Traegde MartinseAbstract:PURPOSE: The aim of this study was to compare dose-area product (DAP), entrance surface dose (ESD), and lens dose to radiologists for an old and a new X-Ray System in a vascular interventional laboratory. MATERIALS AND METHODS: DAP, ESD, fluoroscopy time, number of images, and patient weight were recorded for patients undergoing the following four procedures: percutaneous transluminal angioplasty (PTA) and stenting (divided into two subgroups, lower eXtremities and pelvis), nephrostomy, and treatment for varicocele. Halfway through the registration period, the 9-year-old X-Ray equipment was eXchanged with a new System. Lens doses to the radiologist were measured. RESULTS: There was a reduction in DAP for all procedures: PTA lower eXtremities 31% (12-8 Gy cm(2)), PTA/stenting pelvis 67% (134-44 Gy cm(2)), nephrostomy 39% (7-4 Gy cm(2)), and varicocele 70% (37-11 Gy cm(2)). The reduction in number of images was 17% (158-131), 23% (153-118), 68% (2-1), and 31% (50-35), eXplaining a part of the dose reduction. The reduction in ESD was 33, 60, 38, and 46%. The differences in measured lens doses indicate a dose reduction in three procedures (19-53%) and an increase in one (56%), but differences are not statistically significant. CONCLUSION: DAP and ESD from the X-Ray System were reduced for all procedures. The reduction was greater in the more radiation-demanding procedures.
E Vano - One of the best experts on this subject based on the ideXlab platform.
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radiation doses in patient eye lenses during interventional neuroradiology procedures
2016Co-Authors: R Sánchez, S. Rosati, J M Fernandez, E Vano, L LopeziborAbstract:BACKGROUND AND PURPOSE: Eye lenses are among the most sensitive organs to X-Ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients9 eyes during interventional neuroradiology procedures at a university hospital. MATERIALS AND METHODS: Small optically stimulated luminescence dosimeters were located over patients9 eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane X-Ray System. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. RESULTS: The left eye (located toward the lateral C-arm X-Ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maXimum of 2000 mGy in a single procedure. The patient who received this maXimum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. SiXteen percent of the embolizations resulted in eye doses of >500 mGy. CONCLUSIONS: A relevant fraction of patients received eye doses eXceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.
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influence of the antiscatter grid on dose and image quality in pediatric interventional cardiology X Ray Systems
2013Co-Authors: Carlos Ubeda, L Gonzalez, E Vano, Patricia MirandaAbstract:Objective To present a methodology and eXperimental results to assess the influence, in terms of dose and image quality, of the antiscatter grid (AG) in a pediatric cardiology X-Ray System. Method Entrance surface air kerma and image quality, using a test object and different added thicknesses of polymethyl methacrylate (PMMA), for three different acquisition protocols, were measured with and without the AG, for fluoroscopy and cine modes. The image quality parameters, signal-to-noise ratio (SNR), high-contrast spatial resolution (HCSR) and two figures of merit (FOM) were evaluated. Results The average bucky factor values measured during this eXperiment were 1.99, 2.49, 2.85, and 3.30, respectively for 4, 8, 12, and 16 cm of PMMA. SNR variations do not appear to be relevant when removing the AG. However, the use of AG improves HCSR significantly. Imaging the test object with 4 cm of PMMA seems appropriate without the AG, but for 8 cm (equivalent to chest thicknesses of 12 cm) and greater thicknesses, a good image quality would require the use of AG. Conclusions The AG should not be used for neonates and very young children with chest thicknesses equal to or less than 6 cm and weight less that 6 kg. © 2013 Wiley Periodicals, Inc.
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evaluating phantom image quality parameters to optimise patient radiation dose in dental digital radiology
2012Co-Authors: L Gonzalez, E Vano, Ramon Fernandez, Viviana Ziraldo, Jaime Delgado, Victor Delgado, Javier Moro, Carlos UbedaAbstract:Our objective was to obtain images of a predictable level of quality using an intraoral X-Ray System with digital imaging, avoiding patient overeXposure. A polymethylmethacrylate (PMMA) physical test phantom was imaged at different eXposure times and at various PMMA thicknesses using a dental imaging coupled charge device. Two identical regions of interest (ROIs) were chosen in every image file, and quality was numerically evaluated by measuring high-contrast spatial resolutions, low-contrast thresholds and signal-to-noise ratios. In addition, three practitioners proposed personal quality scores by image inspection. Numerical contents in the ROIs, related to the image quality, were plotted against eXposure time. From here, a simple eXpression linking the eXposure time with the thickness to obtain images of comparable quality was deduced. As a result, the optimum eXposure time for imaging with a predictable level of quality can be inferred. The potential effect could imply savings above 1000 man Sv, roughly 20 % of the collective dose due to dental imaging, over a population of 1540 millions.
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radiation dose and image quality for paediatric interventional cardiology
2008Co-Authors: E Vano, Carlos Ubeda, Fernando Leyton, Patricia MirandaAbstract:Radiation dose and image quality for paediatric protocols in a biplane X-Ray System used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4?20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 ?Gy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 ?Gy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25?45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the X-Ray System. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.
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patient doses from fluoroscopically guided cardiac procedures in pediatrics
2007Co-Authors: L C Martinez, E Vano, F Gutierrez, C Rodriguez, R Gilarranz, M J ManzanasAbstract:Infants and children are a higher risk population for radiation cancer induction compared to adults. Although some values on pediatric patient doses for cardiac procedures have been reported, data to determine reference levels are scarce, especially when compared to those available for adults in diagnostic and therapeutic procedures. The aim of this study is to make a new contribution to the scarce published data in pediatric cardiac procedures and help in the determination of future dose reference levels. This paper presents a set of patient dose values, in terms of air kerma area product (KAP) and entrance surface air kerma (ESAK), measured in a pediatric cardiac catheterization laboratory equipped with a biplane X-Ray System with dynamic flat panel detectors. Cardiologists were properly trained in radiation protection. The study includes 137 patients aged between 10 days and 16 years who underwent diagnostic catheterizations or therapeutic procedures. Demographic data and technical details of the procedures were also gathered. The X-Ray System was submitted to a quality control programme, including the calibration of the transmission ionization chamber. The age distribution of the patients was 47 for <1 year; 52 for 1–<5 years; 25 for 5–<10 years and 13 for 10–<16 years. Median values of KAP were 1.9, 2.9, 4.5 and 15.4 Gy cm2 respectively for the four age bands. These KAP values increase by a factor of 8 when moving through the four age bands. The probability of a fatal cancer per fluoroscopically guided cardiac procedure is about 0.07%. Median values of ESAK for the four age bands were 46, 50, 56 and 163 mGy, which lie far below the threshold for deterministic effects on the skin. These dose values are lower than those published in previous papers.
Patricia Miranda - One of the best experts on this subject based on the ideXlab platform.
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influence of the antiscatter grid on dose and image quality in pediatric interventional cardiology X Ray Systems
2013Co-Authors: Carlos Ubeda, L Gonzalez, E Vano, Patricia MirandaAbstract:Objective To present a methodology and eXperimental results to assess the influence, in terms of dose and image quality, of the antiscatter grid (AG) in a pediatric cardiology X-Ray System. Method Entrance surface air kerma and image quality, using a test object and different added thicknesses of polymethyl methacrylate (PMMA), for three different acquisition protocols, were measured with and without the AG, for fluoroscopy and cine modes. The image quality parameters, signal-to-noise ratio (SNR), high-contrast spatial resolution (HCSR) and two figures of merit (FOM) were evaluated. Results The average bucky factor values measured during this eXperiment were 1.99, 2.49, 2.85, and 3.30, respectively for 4, 8, 12, and 16 cm of PMMA. SNR variations do not appear to be relevant when removing the AG. However, the use of AG improves HCSR significantly. Imaging the test object with 4 cm of PMMA seems appropriate without the AG, but for 8 cm (equivalent to chest thicknesses of 12 cm) and greater thicknesses, a good image quality would require the use of AG. Conclusions The AG should not be used for neonates and very young children with chest thicknesses equal to or less than 6 cm and weight less that 6 kg. © 2013 Wiley Periodicals, Inc.
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staff radiation doses in interventional cardiology correlation with patient eXposure
2009Co-Authors: Eliseo Vano, Carlos Ubeda, Fernando Leyton, Patricia Miranda, L GonzalezAbstract:In pediatric interventional cardiology, cardiologists need to stay closer to the patient than during adult catheterization, and the use of biplane Systems increases the scatter radiation. Occupational radiation risk is rather high, and estimation of lens doses becomes necessary. Deriving factors for assessing these doses from the patient doses displayed in catheterization laboratories can help in preserving staff radiation safety. A biplane X-Ray System and polymethylmethacrylate plates of 4 to 20 cm to simulate pediatric patients have been used. Patient entrance dose rates, dose-area product, and doses to the eyes of the cardiologists for the typical operation modes have been measured. Correlations between patient and staff doses have been obtained. Scatter dose rates increase by a factor of 92 from low fluoroscopy to cine acquisition when phantom thickness increases from 4 to 20 cm. Scatter doses increase linearly with dose-area product for all the thicknesses. Administration of 1 Gy·cm2 to the patient involves 7 μSv to the eyes of the cardiologist (without eXtra protection). In conclusion, the eXperimental correlation factors found between phantom and scatter doses allow a fairly good estimation of staff doses from the dosimetric patient data.
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radiation dose and image quality for paediatric interventional cardiology
2008Co-Authors: E Vano, Carlos Ubeda, Fernando Leyton, Patricia MirandaAbstract:Radiation dose and image quality for paediatric protocols in a biplane X-Ray System used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4?20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 ?Gy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 ?Gy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25?45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the X-Ray System. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.
L Lopezibor - One of the best experts on this subject based on the ideXlab platform.
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radiation doses in patient eye lenses during interventional neuroradiology procedures
2016Co-Authors: R Sánchez, Eliseo Vano, S. Rosati, J M Fernandez, L LopeziborAbstract:BACKGROUND AND PURPOSE: Eye lenses are among the most sensitive organs to X-Ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients9 eyes during interventional neuroradiology procedures at a university hospital. MATERIALS AND METHODS: Small optically stimulated luminescence dosimeters were located over patients9 eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane X-Ray System. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. RESULTS: The left eye (located toward the lateral C-arm X-Ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maXimum of 2000 mGy in a single procedure. The patient who received this maXimum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. SiXteen percent of the embolizations resulted in eye doses of >500 mGy. CONCLUSIONS: A relevant fraction of patients received eye doses eXceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.
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radiation doses in patient eye lenses during interventional neuroradiology procedures
2016Co-Authors: R Sánchez, S. Rosati, J M Fernandez, E Vano, L LopeziborAbstract:BACKGROUND AND PURPOSE: Eye lenses are among the most sensitive organs to X-Ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients9 eyes during interventional neuroradiology procedures at a university hospital. MATERIALS AND METHODS: Small optically stimulated luminescence dosimeters were located over patients9 eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane X-Ray System. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. RESULTS: The left eye (located toward the lateral C-arm X-Ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maXimum of 2000 mGy in a single procedure. The patient who received this maXimum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. SiXteen percent of the embolizations resulted in eye doses of >500 mGy. CONCLUSIONS: A relevant fraction of patients received eye doses eXceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.
J M Fernandez - One of the best experts on this subject based on the ideXlab platform.
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radiation doses in patient eye lenses during interventional neuroradiology procedures
2016Co-Authors: R Sánchez, Eliseo Vano, S. Rosati, J M Fernandez, L LopeziborAbstract:BACKGROUND AND PURPOSE: Eye lenses are among the most sensitive organs to X-Ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients9 eyes during interventional neuroradiology procedures at a university hospital. MATERIALS AND METHODS: Small optically stimulated luminescence dosimeters were located over patients9 eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane X-Ray System. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. RESULTS: The left eye (located toward the lateral C-arm X-Ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maXimum of 2000 mGy in a single procedure. The patient who received this maXimum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. SiXteen percent of the embolizations resulted in eye doses of >500 mGy. CONCLUSIONS: A relevant fraction of patients received eye doses eXceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.
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radiation doses in patient eye lenses during interventional neuroradiology procedures
2016Co-Authors: R Sánchez, S. Rosati, J M Fernandez, E Vano, L LopeziborAbstract:BACKGROUND AND PURPOSE: Eye lenses are among the most sensitive organs to X-Ray radiation and may be considered at risk during neurointerventional radiology procedures. The threshold dose to produce eye lens opacities has been recently reduced to 500 mGy by the International Commission on Radiologic Protection. In this article, the authors investigated the radiation doses delivered to patients9 eyes during interventional neuroradiology procedures at a university hospital. MATERIALS AND METHODS: Small optically stimulated luminescence dosimeters were located over patients9 eyes during 5 diagnostic and 31 therapeutic procedures performed in a biplane X-Ray System. Phantom measurements were also made to determine the level of radiation to the eye during imaging runs with conebeam CT. RESULTS: The left eye (located toward the lateral C-arm X-Ray source) received a 4.5 times greater dose than the right one. The average dose during embolization in the left eye was 300 mGy, with a maXimum of 2000 mGy in a single procedure. The patient who received this maXimum eye dose needed 6 embolization procedures to treat his high-volume AVM. If one took into account those 6 embolizations, the eye dose could be 2-fold. SiXteen percent of the embolizations resulted in eye doses of >500 mGy. CONCLUSIONS: A relevant fraction of patients received eye doses eXceeding the threshold of 500 mGy. A careful optimization of the procedures and follow-up of these patients to evaluate potential lens opacities should be considered.
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influence of patient thickness and operation modes on occupational and patient radiation doses in interventional cardiology
2006Co-Authors: E Vano, J M Fernandez, L Gonzalez, C Prieto, E GuibelaldeAbstract:Patient and staff dose values in an interventional cardiology laboratory for different operational modes and several patient thicknesses (from 16 to 28 cm, simulated using polymethylmethacrylate) are presented. When increasing patient thicknesses and depending on fluoroscopy and cine modes, occupational doses can increase >30 times the baseline level. Scatter dose rates at the cardiologist's position with no radiation protective tools ranged from 1 to 14 mSv h -1 for fluoroscopy, and from 10 to 47 mSv h -1 during cine acquisition. Patient entrance surface air kerma rates increased by nearly 3 and staff dose rates by up to 2.6 when fluoroscopy was moved from the low to the high mode, for a typical 20 cm thickness. The respective increase factors were 6 and 4.2 when patient thickness rose from 16 to 28 cm, and by 10 and 8.3, when comparing cine acquisition with the low fluoroscopy mode. The knowledge of typical dose rates for each X-Ray System in use in catheterisation laboratories is essential in order to optimise protection of patients and staff.
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radiation eXposure to medical staff in interventional and cardiac radiology
1998Co-Authors: E Vano, J M Fernandez, L Gonzalez, E Guibelalde, J I TenAbstract:The aim of this work has been to determine typical occupational dose levels in interventional radiology and cardiology installations and to relate doses to patient and occupational dosimetry through the dose-area product. An eXperimental correlation between environmental dosimetric records and dose-area products in the centres studied was established. The study covered a sample of 83 procedures performed by 10 specialists in siX laboratories. The radiologists and cardiologists monitored wore nine thermoluminescent chips neXt to eyes, forehead, neck, hands, left shoulder, left forearm and left arm during each single procedure. In addition, direct reading electronic devices for environmental dosimetry were placed in the C-arm of the X-Ray System, to estimate roughly the occupational radiation risk level. Typical shoulder doses derived from electronic dosimetry range between 300 and 500 muSv per procedure, assuming no lead protective screens were used. Using these values and patient dose-area data from two l...
