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Abstract
PURPOSE Cataract (opacification of the ocular lens) is a typical tissue reaction (deterministic effect) following ionizing radiation exposure, for which prevention dose limits have been recommended in the radiation protection system. Manifestations of radiation cataracts can vary among individuals, but such potential individual responses remain uncharacterized. Here we review relevant literature and discuss implications for radiation protection. This review assesses evidence for significant modification of radiation-induced cataractogenesis by age at exposure, sex and genetic factors based on current scientific literature. CONCLUSIONS In addition to obvious physical factors (e.g. dose, dose rate, radiation quality, irradiation volume), potential factors modifying individual responses for radiation cataracts include sex, age and genetics, with comorbidity and coexposures also having important roles. There are indications and preliminary data identifying such potential modifiers of radiation cataract incidence or risk, although no firm conclusions can yet be drawn. Further studies and a consensus on the evidence are needed to gain deeper insights into factors determining individual responses regarding radiation cataracts and the implications for radiation protection.
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Affiliation(s)
- Stephen G R Barnard
- UK Health Security Agency (UKHSA), Radiation, Chemical and Environmental Hazards Division (RCEHD), Didcot, UK
| | - Nobuyuki Hamada
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Tokyo, Japan
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Bingyang B, Gang W, Zhiqing S, Li N, Zhou B, Xu S, Li D. A Preliminary Study of Personalized Head CT Scan in Pediatric Patients. Dose Response 2021; 19:1559325820985660. [PMID: 33746652 PMCID: PMC7940743 DOI: 10.1177/1559325820985660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 11/30/2020] [Accepted: 12/13/2020] [Indexed: 01/02/2023] Open
Abstract
Objectives: In the present study, we introduced a practical approach to quantify organ-specific radiation doses and investigated whether low-dose head circumference (HC)-based protocols for non-enhanced head computed tomography (CT) could reduce organs-specific radiation dose in pediatric patients while maintaining high image quality. Methods: A total of 83 pediatric patients were prospectively recruited. Without limits to the HC, 15 patients were selected as a convention group (CON group) and underwent non-enhanced head CT scan with standard-dose protocols (tube current-time products of 250mAs). Low-dose group (LD group), including remaining 68 pediatrics were divided into 3 subgroups based on the HC: 54.1-57.0 cm for LD200mAs group (HC-based protocols of 200mAs), 51.1-54.0 cm for LD150mAs group (HC-based protocols of 150mAs), 48.1-51.0 cm for LD100mAs group (HC-based protocols of 100mAs). Subjective and objective image quality was evaluated and measured by 2 experienced radiologists. Radimetrics was used to calculate organs-specific radiation dose, including the brain, eye lenses, and salivary glands. Results: In CON250mAs group, radiation doses in the brain and salivary glands were conversely correlated with HC, and pediatric patients with smaller HC received higher organs-specific radiation dose. Reducing tube current-time product from 250 to 100mAs could significantly reduce the organ-specific radiation dose. The subjective image quality score ≥ 3.0 is acceptable for diagnosis purposes. The signal to noise ratio (SNR) and the contrast to noise ratio (CNR) of bilateral thalamus and centrum semiovale in 3 LD subgroups were not statistically different compared with the CON group. Conclusion: Our research indicated that low-dose HC-based protocols of non-enhanced head CT scan can evidently reduce the organ-specific radiation doses, while maintaining high image quality. HC can serve as a vital tool to guide personalized low-dose head CT scan for pediatric patients.
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Affiliation(s)
| | - Wang Gang
- Third Hospital of Jilin University, Changchun, China
| | - Shao Zhiqing
- Jilin University First Hospital, Changchun, China
| | - Nan Li
- Jilin University First Hospital, Changchun, China
| | - BoXu Zhou
- Jilin University First Hospital, Changchun, China
| | - ShuJia Xu
- Jilin University First Hospital, Changchun, China
| | - Dan Li
- Jilin University First Hospital, Changchun, China
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Zeller AN, Neuhaus MT, Gessler N, Skade S, Korn P, Jehn P, Gellrich NC, Zimmerer RM. Self-centering second-generation patient-specific functionalized implants for deep orbital reconstruction. JOURNAL OF STOMATOLOGY, ORAL AND MAXILLOFACIAL SURGERY 2020; 122:372-380. [PMID: 33385579 DOI: 10.1016/j.jormas.2020.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 11/24/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
Deep and complete reconstruction of the orbital cavity has been shown to be essential for preventing enophthalmos and hypoglobus in patients with orbital defects or deformities. Additively manufactured patient-specific titanium implants provide unlimited options in design. However, implant malpositioning can still occur, even when intraoperative imaging and navigation are used. In this study, we investigated novel orbital implants containing features facilitating self-centering. Accuracy of implant placement and reconstruction of the orbital dimensions were compared retrospectively between self-centering second-generation patient-specific functionalized orbital implants (study group) and CAD-based individualized implants (control group). Design features of implants in the study group included functionalization with navigation tracks, a preventive design, and flanges - so called stabilizers - towards opposite orbital walls. Implant position was evaluated by fusion of preoperative virtual plans and the post-therapeutic imaging. Aberrances were quantified by 3D heatmap analysis. 31 patients were assigned to the study group and 50 to the control group, respectively. In the study group, most implants were designed with either one (n = 18, 58.06%) or two (n = 10, 32.26%) stabilizers. Twice (6.45%), one stabilizer had to be shortened intraoperatively. Implant fit analysis revealed a significantly more precise (p < 0.001) positioning in the study group (n = 22/31) than in the control group (n = 42/50). Self-centering second-generation patient-specific functionalized orbital implants showed significantly more accurate implant positioning, facilitating the transformation of virtual plans into patient's anatomy. The presented design provides an additional instrument for intraoperative quality control besides intraoperative imaging and navigation.
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Affiliation(s)
| | - Michael Tobias Neuhaus
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Nora Gessler
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Sandra Skade
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Philippe Korn
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Philipp Jehn
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Nils-Claudius Gellrich
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Rüdiger M Zimmerer
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany.
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Gaudreau K, Thome C, Weaver B, Boreham DR. Cataract Formation and Low-Dose Radiation Exposure from Head Computed Tomography (CT) Scans in Ontario, Canada, 1994–2015. Radiat Res 2020; 193:322-330. [DOI: 10.1667/rr15504.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Katherine Gaudreau
- Northern Ontario School of Medicine, Sudbury, Canada, P3E 2C6 and Thunder Bay, Canada, P7B 5E1
| | - Christopher Thome
- Northern Ontario School of Medicine, Sudbury, Canada, P3E 2C6 and Thunder Bay, Canada, P7B 5E1
| | - Bruce Weaver
- Northern Ontario School of Medicine, Sudbury, Canada, P3E 2C6 and Thunder Bay, Canada, P7B 5E1
| | - Douglas R. Boreham
- Northern Ontario School of Medicine, Sudbury, Canada, P3E 2C6 and Thunder Bay, Canada, P7B 5E1
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Harbron RW, Ainsbury EA, Barnard SGR, Lee C, McHugh K, Berrington de González A, Edyvean S, Pearce MS. Radiation dose to the lens from CT of the head in young people. Clin Radiol 2019; 74:816.e9-816.e17. [PMID: 31375261 DOI: 10.1016/j.crad.2019.06.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 06/28/2019] [Indexed: 11/28/2022]
Abstract
AIM To determine cumulative scan frequencies and estimate lens dose for paediatric computed tomography (CT) head examinations in the context of potential cataract risk. MATERIALS AND METHODS The cumulative number of head-region CT examinations among a cohort of 410,997 children and young adults who underwent CT in the UK between 1985 and 2014 was calculated. Images from a sample of these head examinations (n=668) were reviewed to determine the level of eye inclusion. Lens dose per scan was estimated using the computer program, NCICT V1.0, for different levels of eye inclusion and exposure settings typical of past and present clinical practice. RESULTS In total 284,878 patients underwent 448,108 head-region CT examinations. The majority of patients (72%) had a single recorded head-region examination. A small subset (∼1%, n=2,494) underwent ≥10 examinations, while 0.1% (n=387) underwent ≥20. The lens was included within the imaged region for 57% of reviewed routine head examinations. In many cases, this appeared to be intentional, i.e. protocol driven. In others, there appeared to have been an attempt to exclude the eyes through gantry angulation. Estimated lens doses were 20-75 mGy (mean: 47 mGy) where the eye was fully included within the examination range and 2-7 mGy (mean: 3.1 mGy) where the lens was fully excluded. Potential cumulative lens doses ranged from ∼3 mGy to ∼4,700 mGy, with 2,335 patients potentially receiving >500 mGy. CONCLUSION The majority of young people will receive cumulative lens doses well below 500 mGy, meaning the risk of cataract induction is likely to be very small.
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Affiliation(s)
- R W Harbron
- Institute of Health and Society, Newcastle University, Royal Victoria Infirmary, Queen Victoria Road, Newcastle-upon-Tyne NE1 4LP, UK; NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, UK.
| | - E A Ainsbury
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, UK
| | - S G R Barnard
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, UK
| | - C Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - K McHugh
- Radiology Department, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - A Berrington de González
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - S Edyvean
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, UK
| | - M S Pearce
- Institute of Health and Society, Newcastle University, Royal Victoria Infirmary, Queen Victoria Road, Newcastle-upon-Tyne NE1 4LP, UK; NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, UK
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Sun W, Zhang L, Wang L, Ren Y, She Y, Su H, Jiang G, Chen C. Three-Dimensionally Printed Template for Percutaneous Localization of Multiple Lung Nodules. Ann Thorac Surg 2019; 108:883-888. [PMID: 31009631 DOI: 10.1016/j.athoracsur.2019.03.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/21/2019] [Accepted: 03/18/2019] [Indexed: 11/17/2022]
Abstract
BACKGROUND When multiple target lung nodules exist, the computed tomography (CT)-guided percutaneous localization procedure becomes complicated. In this study, a three-dimensional (3D)-printed template was designed that could guide hook wire localization of multiple lung nodules. The pilot study aimed for preliminary validation of the feasibility of template-guided localization for multiple lesions. METHODS Patients with multiple lung nodules (<2 cm) and who were scheduled for surgical resection were recruited for participation in this study. After securing their preadmission CT images, the study investigators reconstructed a 3D thorax model from which they designed a digital model as a navigational template. A physical template was then printed for guiding the percutaneous localization of lung nodules. The localization accuracy was evaluated on the basis of the deviation between the localizer and the nodule. RESULTS From April 2018 to November 2018, the study enrolled 16 patients with 34 lung nodules. All nodules were successfully localized under template guidance, with a median procedural time of 10.0minutes (interquartile range [IQR], 8.5-12.6 minutes) and a median radiation exposure of 235 mGy • cm (IQR, 195-254 mGy • cm). The median deviation from the hook wires and nodule centers was 9.0 mm (IQR, 6.2-11.8 mm). Except for 2 cases of pneumothorax without need for further intervention, no complications occurred. CONCLUSIONS Navigational templates built using 3D printing may serve as an effective approach for facilitating localization of multiple lung nodules.
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Affiliation(s)
- Weiyan Sun
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lei Zhang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Long Wang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yijiu Ren
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yunlang She
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hang Su
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Gening Jiang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Chang Chen
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.
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Akhlaghi P, Ebrahimi-Khankook A, Vejdani-Noghreiyan A. The effects of simulating a realistic eye model on the eye dose of an adult male undergoing head computed tomography. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2017; 56:177-186. [PMID: 28283750 DOI: 10.1007/s00411-017-0686-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 02/22/2017] [Indexed: 06/06/2023]
Abstract
In head computed tomography, radiation upon the eye lens (as an organ with high radiosensitivity) may cause lenticular opacity and cataracts. Therefore, quantitative dose assessment due to exposure of the eye lens and surrounding tissue is a matter of concern. For this purpose, an accurate eye model with realistic geometry and shape, in which different eye substructures are considered, is needed. To calculate the absorbed radiation dose of visual organs during head computed tomography scans, in this study, an existing sophisticated eye model was inserted at the related location in the head of the reference adult male phantom recommended by the International Commission on Radiological Protection (ICRP). Then absorbed doses and distributions of energy deposition in different parts of this eye model were calculated and compared with those based on a previous simple eye model. All calculations were done using the Monte Carlo code MCNP4C for tube voltages of 80, 100, 120 and 140 kVp. In spite of the similarity of total dose to the eye lens for both eye models, the dose delivered to the sensitive zone, which plays an important role in the induction of cataracts, was on average 3% higher for the sophisticated model as compared to the simple model. By increasing the tube voltage, differences between the total dose to the eye lens between the two phantoms decrease to 1%. Due to this level of agreement, use of the sophisticated eye model for patient dosimetry is not necessary. However, it still helps for an estimation of doses received by different eye substructures separately.
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Affiliation(s)
- Parisa Akhlaghi
- Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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Hu P, Kong Y, Chen B, Liu Q, Zhuo W, Liu H. Shielding Effect of Lead Glasses on Radiologists' Eye Lens Exposure in Interventional Procedures. RADIATION PROTECTION DOSIMETRY 2017; 174:136-140. [PMID: 27150520 DOI: 10.1093/rpd/ncw098] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/09/2016] [Indexed: 06/05/2023]
Abstract
To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm2-sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm2 per glass) lens are recommended.
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Affiliation(s)
- Panpan Hu
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
- Fudan University Shanghai Cancer Center, Shanghai 200032, China
| | - Yan Kong
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
- Wuxi No. 4 People's Hospital, Jiangnan University, Wuxi, Jiangsu 214062, China
| | - Bo Chen
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Qianqian Liu
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Weihai Zhuo
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Haikuan Liu
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
- Nuclear Engineering and Engineering Physics Program, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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Shore RE. Radiation and cataract risk: Impact of recent epidemiologic studies on ICRP judgments. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 770:231-237. [DOI: 10.1016/j.mrrev.2016.06.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 02/04/2023]
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Evaluation of a Net Dose-Reducing Organ-Based Tube Current Modulation Technique: Comparison With Standard Dose and Bismuth-Shielded Acquisitions. AJR Am J Roentgenol 2016; 206:1233-40. [DOI: 10.2214/ajr.15.15778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Langner S. Optimized imaging of the midface and orbits. GMS CURRENT TOPICS IN OTORHINOLARYNGOLOGY, HEAD AND NECK SURGERY 2016; 14:Doc05. [PMID: 26770279 PMCID: PMC4702054 DOI: 10.3205/cto000120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A variety of imaging techniques are available for imaging the midface and orbits. This review article describes the different imaging techniques based on the recent literature and discusses their impact on clinical routine imaging. Imaging protocols are presented for different diseases and the different imaging modalities.
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Affiliation(s)
- Sönke Langner
- Institute for Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, Germany
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Heusch P, Kröpil P, Buchbender C, Aissa J, Lanzman RS, Heusner TA, Ewen K, Antoch G, Fürst G. Radiation exposure of the radiologist's eye lens during CT-guided interventions. Acta Radiol 2014; 55:86-90. [PMID: 23884839 DOI: 10.1177/0284185113493222] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND In the past decade the number of computed tomography (CT)-guided procedures performed by interventional radiologists have increased, leading to a significantly higher radiation exposure of the interventionalist's eye lens. Because of growing concern that there is a stochastic effect for the development of lens opacification, eye lens dose reduction for operators and patients should be of maximal interest. PURPOSE To determine the interventionalist's equivalent eye lens dose during CT-guided interventions and to relate the results to the maximum of the recommended equivalent dose limit. MATERIAL AND METHODS During 89 CT-guided interventions (e.g. biopsies, drainage procedures, etc.) measurements of eye lens' radiation doses were obtained from a dedicated dosimeter system for scattered radiation. The sensor of the personal dosimeter system was clipped onto the side of the lead glasses which was located nearest to the CT gantry. After the procedure, radiation dose (µSv), dose rate (µSv/min) and the total exposure time (s) were recorded. RESULTS For all 89 interventions, the median total exposure lens dose was 3.3 µSv (range, 0.03-218.9 µSv) for a median exposure time of 26.2 s (range, 1.1-94.0 s). The median dose rate was 13.9 µSv/min (range, 1.1-335.5 µSv/min). CONCLUSION Estimating 50-200 CT-guided interventions per year performed by one interventionalist, the median dose of the eye lens of the interventional radiologist does not exceed the maximum of the ICRP-recommended equivalent eye lens dose limit of 20 mSv per year.
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Affiliation(s)
- Philipp Heusch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Patric Kröpil
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Christian Buchbender
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Joel Aissa
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Rotem S Lanzman
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Till A Heusner
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Klaus Ewen
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
| | - Günther Fürst
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University of Dusseldorf, Dusseldorf, Germany
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Abstract
Cholesteatomas can be subclassified into genuine and acquired forms. Whilst epidermoid formations are the generally accepted cause of genuine cholesteatomas, metaplasia, immigration, proliferation and retraction pocket theories have all been proposed to explain the development of acquired cholesteatomas. Clinically, paediatric cholesteatomas exhibit more extensive and aggressive growth than those arising in adulthood. Molecular biological differences in terms of angiogenesis, cytokine expression and particularly the more marked inflammatory responses of the perimatrix could potentially explain these clinical differences. The surgical therapy of paediatric cholesteatomas should be adapted to the individual pathological findings, although where possible a canal wall up procedure is preferred during initial surgery. The "inside-out" mastoidectomy tracking-technique combines the benefits of a good surgical overview with those of a physiological postoperative auditory canal.
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The risk of cataract associated with repeated head and neck CT studies: a nationwide population-based study. AJR Am J Roentgenol 2013; 201:626-30. [PMID: 23971456 DOI: 10.2214/ajr.12.9652] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Medical radiation-induced cataracts, especially those resulting from head and neck CT studies, are an issue of concern. The current study aimed to determine the risk of cataract associated with repeated radiation exposure from head and neck CT. MATERIALS AND METHODS This study used information from a random sample of 2 million persons enrolled in the nationally representative Taiwan National Health Insurance Research Database. Exposed cases consisted of patients with head and neck tumor 10-50 years old who underwent at least one CT between 2000 and 2009. The nonexposed control group was composed of subjects who were never exposed to CT studies but who were matched by time of enrollment, age, sex, history of coronary artery disease, hypertension, and diabetes. RESULTS There were 2776 patients in the exposed group and 27,761 matched subjects in the nonexposed group. The exposed group had higher overall incidence of cataracts (0.97% vs 0.72%; adjusted hazard ratio [HR], 1.76; 95% CI, 1.18-2.63). Further stratifying the number of CT studies in the exposed group into one or two, three or four, and five or more revealed that cataract incidence increased gradually with increasing frequency of CT studies (0.79%, 0.93%, and 1.45%, respectively) (p=0.001, adjusted for trend). Radiation exposure due to repeated head and neck CT studies was independently associated with an increased risk of developing cataracts when the cumulative CT exposure frequency involved more than four studies (adjusted HR, 2.12; 95% CI, 1.09-4.14). CONCLUSION Repeated exposure to head and neck CT is significantly associated with increased risk of cataract.
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Gelesko S, Markiewicz MR, Bell RB. Responsible and Prudent Imaging in the Diagnosis and Management of Facial Fractures. Oral Maxillofac Surg Clin North Am 2013; 25:545-60. [DOI: 10.1016/j.coms.2013.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Quantitative and Qualitative Comparison of Standard-Dose and Low-Dose Pediatric Head Computed Tomography. J Comput Assist Tomogr 2013; 37:377-81. [DOI: 10.1097/rct.0b013e31828426de] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Blakely EA. Lauriston S. Taylor Lecture on radiation protection and measurements: what makes particle radiation so effective? HEALTH PHYSICS 2012; 103:508-28. [PMID: 23032880 PMCID: PMC3507469 DOI: 10.1097/hp.0b013e31826a5b85] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The scientific basis for the physical and biological effectiveness of particle radiations has emerged from many decades of meticulous basic research. A diverse array of biologically relevant consequences at the molecular, cellular, tissue, and organism level have been reported, but what are the key processes and mechanisms that make particle radiation so effective, and what competing processes define dose dependences? Recent studies have shown that individual genotypes control radiation-regulated genes and pathways in response to radiations of varying ionization density. The fact that densely ionizing radiations can affect different gene families than sparsely ionizing radiations, and that the effects are dose- and time-dependent, has opened up new areas of future research. The complex microenvironment of the stroma and the significant contributions of the immune response have added to our understanding of tissue-specific differences across the linear energy transfer (LET) spectrum. The importance of targeted versus nontargeted effects remains a thorny but elusive and important contributor to chronic low dose radiation effects of variable LET that still needs further research. The induction of cancer is also LET-dependent, suggesting different mechanisms of action across the gradient of ionization density. The focus of this 35th Lauriston S. Taylor Lecture is to chronicle the step-by-step acquisition of experimental clues that have refined our understanding of what makes particle radiation so effective, with emphasis on the example of radiation effects on the crystalline lens of the human eye.
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Affiliation(s)
- Eleanor A Blakely
- Lawrence Berkeley National Laboratory, One Cyclotron Road, MS 977, Berkeley, CA 94720, USA.
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CT Scans in Young People in Great Britain: Temporal and Descriptive Patterns, 1993-2002. Radiol Res Pract 2012; 2012:594278. [PMID: 22792457 PMCID: PMC3390133 DOI: 10.1155/2012/594278] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 04/24/2012] [Indexed: 11/17/2022] Open
Abstract
Background. Although using computed tomography (CT) can be greatly beneficial, the associated relatively high radiation doses have led to growing concerns in relation to potential associations with risk of future cancer. Very little has been published regarding the trends of CT use in young people. Therefore, our objective was to assess temporal and other patterns in CT usage among patients aged under 22 years in Great Britain from 1993 to 2002. Methods. Electronic data were obtained from the Radiology Information Systems of 81 hospital trusts within Great Britain. All included patients were aged under 22 years and examined using CT between 1993 and 2002, with accessible radiology records. Results. The number of CT examinations doubled over the study period. While increases in numbers of recorded examinations were seen across all age groups, the greatest increases were in the older patients, most notably those aged 15-19 years of age. Sixty percent of CT examinations were of the head, with the percentages varying with calendar year and patient age. Conclusions. In contrast to previous data from the North of England, the doubling of CT use was not accompanied by an increase in numbers of multiple examinations to the same individual.
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Vorona GA, Zuccoli G, Sutcavage T, Clayton BL, Ceschin RC, Panigrahy A. The use of adaptive statistical iterative reconstruction in pediatric head CT: a feasibility study. AJNR Am J Neuroradiol 2012; 34:205-11. [PMID: 22627796 DOI: 10.3174/ajnr.a3122] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Iterative reconstruction techniques facilitate CT dose reduction; though to our knowledge, no group has explored using iterative reconstruction with pediatric head CT. Our purpose was to perform a feasibility study to assess the use of ASIR in a small group of pediatric patients undergoing head CT. MATERIALS AND METHODS An Alderson-Rando head phantom was scanned at decreasing 10% mA intervals relative to our standard protocol, and each study was then reconstructed at 10% ASIR intervals. An intracranial region of interest was consistently placed to estimate noise. Our ventriculoperitoneal shunt CT protocol was subsequently modified, and patients were scanned at 20% ASIR with approximately 20% mA reductions. ASIR studies were anonymously compared with older non-ASIR studies from the same patients by 2 attending pediatric neuroradiologists for diagnostic utility, sharpness, noise, and artifacts. RESULTS The phantom study demonstrated similar noise at 100% mA/0% ASIR (3.9) and 80% mA/20% ASIR (3.7). Twelve pediatric patients were scanned at reduced dose at 20% ASIR. The average CTDI(vol) and DLP values of the 20% ASIR studies were 22.4 mGy and 338.4 mGy-cm, and for the non-ASIR studies, they were 28.8 mGy and 444.5 mGy-cm, representing statistically significant decreases in the CTDI(vol) (22.1%, P = .00007) and DLP (23.9%, P = .0005) values. There were no significant differences between the ASIR studies and non-ASIR studies with respect to diagnostic acceptability, sharpness, noise, or artifacts. CONCLUSIONS Our findings suggest that 20% ASIR can provide approximately 22% dose reduction in pediatric head CT without affecting image quality.
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Affiliation(s)
- G A Vorona
- Department of Radiology, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
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