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Lee C, Moroz B, Thome C, Gaudreau K, Emami P, Little MP. Reconstruction of organ doses for patients undergoing computed tomography examinations in Canada 1992-2019. RADIATION PROTECTION DOSIMETRY 2024; 200:379-386. [PMID: 38186237 PMCID: PMC10954068 DOI: 10.1093/rpd/ncad315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 10/31/2023] [Accepted: 11/30/2023] [Indexed: 01/09/2024]
Abstract
We derived the first comprehensive organ dose library for Canadian pediatric and adult patients who underwent computed tomography (CT) scans between 1992 and 2019 to support epidemiological analysis of radiation risk. We calculated organ absorbed doses for Canadian CT patients in two steps. First, we modeled Computed Tomography Dose Index (CTDI) values by patient age, scan body part, and scan year for the scan period between 1992 and 2019 using national survey data conducted in Canada and partially the United Kingdom survey data as surrogates. Second, we converted CTDI values to organ absorbed doses using a library of organ dose conversion coefficients built in an organ dose calculation program, the National Cancer Institute dosimetry system for CT. In result, we created a library of doses delivered to 33 organs and tissues by different patient ages and genders, scan body parts and scan years. In the scan period before 2000, the organs receiving the greatest dose in the head, chest and abdomen-pelvis scans were the active marrow (3.7-15.2 mGy), lungs (54.7-62.8 mGy) and colon (54.9-68.5 mGy), respectively. We observed organ doses reduced by 24% (pediatric head and torso scans, and adult head scans) and 55% (adult torso scans) after 2000. The organ dose library will be used to analyse the risk of radiation exposure from CT scans in the Canadian CT patient cohort.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, United States
| | - Brian Moroz
- Computing and Software Solutions for Science, LLC, Bethany Beach, DE, 19930, United States
| | - Christopher Thome
- Medical Sciences Division, NOSM University, Sudbury, ON, P3E 2C6, Canada
- School of Natural Sciences, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Katherine Gaudreau
- Medical Sciences Division, NOSM University, Sudbury, ON, P3E 2C6, Canada
| | - Pirouz Emami
- Department of Physics & Astronomy, McMaster University, Hamilton, ON, ON L8S 4L8, Canada
| | - Mark P Little
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, United States
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2
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Caramenti L, Gradowska PL, Moriña D, Byrnes G, Cardis E, Hauptmann M. Finite-Sample Bias of the Linear Excess Relative Risk in Cohort Studies of Computed Tomography-Related Radiation Exposure and Cancer. Radiat Res 2024; 201:206-214. [PMID: 38323646 DOI: 10.1667/rade-23-00187.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 01/22/2024] [Indexed: 02/08/2024]
Abstract
The linear excess relative risk (ERR) is the most commonly reported measure of association in radiation epidemiological studies, when individual dose estimates are available. While the asymptotic properties of the ERR estimator are well understood, there is evidence of small sample bias in case-control studies of treatment-related radiation exposure and second cancer risk. Cohort studies of cancer risk after exposure to low doses of radiation from diagnostic procedures, e.g., computed tomography (CT) examinations, typically have small numbers of cases and risks are small. Therefore, understanding the properties of the estimated ERR is essential for interpretation and analysis of such studies. We present results of a simulation study that evaluates the finite-sample bias of the ERR estimated by time-to-event analyses and its confidence interval using simulated data, resembling a retrospective cohort study of radiation-related leukemia risk after CT examinations in childhood and adolescence. Furthermore, we evaluate how the Firth-corrected estimator reduces the finite-sample bias of the classical estimator. We show that the ERR is overestimated by about 30% for a cohort of about 150,000 individuals, with 42 leukemia cases observed on average. The bias is reduced for higher baseline incidence rates and for higher values of the true ERR. As the number of cases increases, the ERR is approximately unbiased. The Firth correction reduces the bias for all cohort sizes to generally around or under 5%. Epidemiological studies showing an association between radiation exposure from pediatric CT and cancer risk, unless very large, may overestimate the magnitude of the relationship, while there is no evidence of an increased chance for false-positive results. Conducting large studies, perhaps by pooling individual studies to increase the number of cases, should be a priority. If this is not possible, Firth correction should be applied to reduce small-sample bias.
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Affiliation(s)
- L Caramenti
- Institute of Biostatistics and Registry Research, Brandenburg Medical School Theodor Fontane; Neuruppin, Germany
| | - P L Gradowska
- Erasmus MC Cancer Institute; Rotterdam, The Netherlands
| | - D Moriña
- Department of Econometrics, Statistics and Applied Economics, Riskcenter-IREA, Universitat de Barcelona (UB); Barcelona, Spain
| | - G Byrnes
- International Agency for Research in Cancer (IARC); Lyon, France
| | - E Cardis
- Institute for Global Health, ISGlobal; Barcelona, Spain
- Universitat Pompeu Fabra (UPF); Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP); Madrid, Spain
| | - M Hauptmann
- Institute of Biostatistics and Registry Research, Brandenburg Medical School Theodor Fontane; Neuruppin, Germany
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3
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Canet M, Harbron R, Thierry-Chef I, Cardis E. Cancer Effects of Low to Moderate Doses of Ionizing Radiation in Young People with Cancer-Predisposing Conditions: A Systematic Review. Cancer Epidemiol Biomarkers Prev 2022; 31:1871-1889. [PMID: 35861626 PMCID: PMC9530642 DOI: 10.1158/1055-9965.epi-22-0393] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/10/2022] [Accepted: 07/18/2022] [Indexed: 01/07/2023] Open
Abstract
Moderate to high doses of ionizing radiation (IR) are known to increase the risk of cancer, particularly following childhood exposure. Concerns remain regarding risks from lower doses and the role of cancer-predisposing factors (CPF; genetic disorders, immunodeficiency, mutations/variants in DNA damage detection or repair genes) on radiation-induced cancer (RIC) risk. We conducted a systematic review of evidence that CPFs modify RIC risk in young people. Searches were performed in PubMed, Scopus, Web of Science, and EMBASE for epidemiologic studies of cancer risk in humans (<25 years) with a CPF, exposed to low-moderate IR. Risk of bias was considered. Fifteen articles focusing on leukemia, lymphoma, breast, brain, and thyroid cancers were included. We found inadequate evidence that CPFs modify the risk of radiation-induced leukemia, lymphoma, brain/central nervous system, and thyroid cancers and limited evidence that BRCA mutations modify radiation-induced breast cancer risk. Heterogeneity was observed across studies regarding exposure measures, and the numbers of subjects with CPFs other than BRCA mutations were very small. Further studies with more appropriate study designs are needed to elucidate the impact of CPFs on RIC. They should focus either on populations of carriers of specific gene mutations or on common susceptible variants using polygenic risk scores.
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Affiliation(s)
- Maelle Canet
- Barcelona Institute of Global Health (ISGlobal), Barcelona, Spain.,University Pompeu Fabra, Barcelona, Spain.,CIBER Epidemiologia y Salud Pública, Madrid, Spain
| | - Richard Harbron
- Barcelona Institute of Global Health (ISGlobal), Barcelona, Spain.,University Pompeu Fabra, Barcelona, Spain.,CIBER Epidemiologia y Salud Pública, Madrid, Spain
| | - Isabelle Thierry-Chef
- Barcelona Institute of Global Health (ISGlobal), Barcelona, Spain.,University Pompeu Fabra, Barcelona, Spain.,CIBER Epidemiologia y Salud Pública, Madrid, Spain
| | - Elisabeth Cardis
- Barcelona Institute of Global Health (ISGlobal), Barcelona, Spain.,University Pompeu Fabra, Barcelona, Spain.,CIBER Epidemiologia y Salud Pública, Madrid, Spain.,Corresponding Author: Elisabeth Cardis, Institut de Salut Global de Barcelona - Campus MAR, Parc de Recerca Biomèdica de Barcelona (PRBB), Doctor Aiguader, 88, 08003 Barcelona, Spain. Phone: 349-3214-7312; E-mail:
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4
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Little MP, Patel A, Lee C, Hauptmann M, Berrington de Gonzalez A, Albert P. Impact of Reverse Causation on Estimates of Cancer Risk Associated With Radiation Exposure From Computerized Tomography: A Simulation Study Modeled on Brain Cancer. Am J Epidemiol 2022; 191:173-181. [PMID: 34642734 DOI: 10.1093/aje/kwab247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 08/27/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
Use of computed tomography (CT) scanning has increased substantially since its introduction in the 1990s. Several authors have reported increased risk of leukemia and brain tumors associated with radiation exposure from CT scans. However, reverse causation is a concern, particularly for brain cancer; in other words, the CT scan may have been taken because of preexisting cancer and therefore not have been a cause. We assessed the possibility of reverse causation via a simulation study focused on brain tumors, using a simplified version of the data structure for recent CT studies. Five-year-lagged and unlagged analyses implied an observed excess risk per scan up to 70% lower than the true excess risk per scan, particularly when more than 10% of persons with latent cancer had increased numbers of scans or the extra scanning rate after development of latent cancer was greater than 2 scans/year; less extreme values of these parameters imply little risk attenuation. Without a lag and when more than 20% of persons with latent cancer had increased scans-an arguably implausible scenario-the excess risk per scan was increased over the true excess risk per scan by up to 35%-40%. This study suggests that with a realistic lag, reverse causation results in downwardly biased risk, a result of induced classical measurement error, and is therefore unlikely to produce a spurious positive association between cancer and radiation dose from CT scans.
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Berrington de Gonzalez A, Pasqual E, Veiga L. Epidemiological studies of CT scans and cancer risk: the state of the science. Br J Radiol 2021; 94:20210471. [PMID: 34545766 DOI: 10.1259/bjr.20210471] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
20 years ago, 3 manuscripts describing doses and potential cancer risks from CT scans in children raised awareness of a growing public health problem. We reviewed the epidemiological studies that were initiated in response to these concerns that assessed cancer risks from CT scans using medical record linkage. We evaluated the study methodology and findings and provide recommendations for optimal study design for new efforts. We identified 17 eligible studies; 13 with published risk estimates, and 4 in progress. There was wide variability in the study methodology, however, which made comparison of findings challenging. Key differences included whether the study focused on childhood or adulthood exposure, radiosensitive outcomes (e.g. leukemia, brain tumors) or all cancers, the exposure metrics (e.g. organ doses, effective dose or number of CTs) and control for biases (e.g. latency and exclusion periods and confounding by indication). We were able to compare results for the subset of studies that evaluated leukemia or brain tumors. There were eight studies of leukemia risk in relation to red bone marrow (RBM) dose, effective dose or number of CTs; seven reported a positive dose-response, which was statistically significant (p < 0.05) in four studies. Six of the seven studies of brain tumors also found a positive dose-response and in five, this was statistically significant. Mean RBM dose ranged from 6 to 12 mGy and mean brain dose from 18 to 43 mGy. In a meta-analysis of the studies of childhood exposure the summary ERR/100 mGy was 1.78 (95%CI: 0.01-3.53) for leukemia/myelodisplastic syndrome (n = 5 studies) and 0.80 (95%CI: 0.48-1.12) for brain tumors (n = 4 studies) (p-heterogeneity >0.4). Confounding by cancer pre-disposing conditions was unlikely in these five studies of leukemia. The summary risk estimate for brain tumors could be over estimated, however, due to reverse causation. In conclusion, there is growing evidence from epidemiological data that CT scans can cause cancer. The absolute risks to individual patients are, however, likely to be small. Ongoing large multicenter cohorts and future pooling efforts will provide more precise risk quantification.
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Affiliation(s)
- Amy Berrington de Gonzalez
- Radiation Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, Bethesda, MD, USA
| | - Elisa Pasqual
- Radiation Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, Bethesda, MD, USA
| | - Lene Veiga
- Radiation Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, Bethesda, MD, USA
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6
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Thierry-Chef I, Ferro G, Le Cornet L, Dabin J, Istad TS, Jahnen A, Lee C, Maccia C, Malchair F, Olerud HM, Harbron RW, Figuerola J, Hermen J, Moissonnier M, Bernier MO, Bosch de Basea MB, Byrnes G, Cardis E, Hauptmann M, Journy N, Kesminiene A, Meulepas JM, Pokora R, Simon SL. Dose Estimation for the European Epidemiological Study on Pediatric Computed Tomography (EPI-CT). Radiat Res 2021; 196:74-99. [PMID: 33914893 DOI: 10.1667/rade-20-00231.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 03/26/2021] [Indexed: 11/03/2022]
Abstract
Within the European Epidemiological Study to Quantify Risks for Paediatric Computerized Tomography (EPI-CT study), a cohort was assembled comprising nearly one million children, adolescents and young adults who received over 1.4 million computed tomography (CT) examinations before 22 years of age in nine European countries from the late 1970s to 2014. Here we describe the methods used for, and the results of, organ dose estimations from CT scanning for the EPI-CT cohort members. Data on CT machine settings were obtained from national surveys, questionnaire data, and the Digital Imaging and Communications in Medicine (DICOM) headers of 437,249 individual CT scans. Exposure characteristics were reconstructed for patients within specific age groups who received scans of the same body region, based on categories of machines with common technology used over the time period in each of the 276 participating hospitals. A carefully designed method for assessing uncertainty combined with the National Cancer Institute Dosimetry System for CT (NCICT, a CT organ dose calculator), was employed to estimate absorbed dose to individual organs for each CT scan received. The two-dimensional Monte Carlo sampling method, which maintains a separation of shared and unshared error, allowed us to characterize uncertainty both on individual doses as well as for the entire cohort dose distribution. Provided here are summaries of estimated doses from CT imaging per scan and per examination, as well as the overall distribution of estimated doses in the cohort. Doses are provided for five selected tissues (active bone marrow, brain, eye lens, thyroid and female breasts), by body region (i.e., head, chest, abdomen/pelvis), patient age, and time period (1977-1990, 1991-2000, 2001-2014). Relatively high doses were received by the brain from head CTs in the early 1990s, with individual mean doses (mean of 200 simulated values) of up to 66 mGy per scan. Optimization strategies implemented since the late 1990s have resulted in an overall decrease in doses over time, especially at young ages. In chest CTs, active bone marrow doses dropped from over 15 mGy prior to 1991 to approximately 5 mGy per scan after 2001. Our findings illustrate patterns of age-specific doses and their temporal changes, and provide suitable dose estimates for radiation-induced risk estimation in epidemiological studies.
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Affiliation(s)
- Isabelle Thierry-Chef
- International Agency for Research on Cancer, Lyon, France
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Gilles Ferro
- International Agency for Research on Cancer, Lyon, France
| | - Lucian Le Cornet
- Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Mainz, Germany
- German Cancer Research Center, Heidelberg, Germany
| | - Jérémie Dabin
- Belgian Nuclear Research Centre, SCK CEN, Mol, Belgium
| | - Tore S Istad
- Norwegian Radiation and Nuclear Safety Authority, NO-0213 Oslo, Norway
| | - Andreas Jahnen
- Luxembourg Institute of Science and Technology, Esch-sur-Alzette, Luxembourg
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland
| | | | | | - Hilde M Olerud
- University of South-Eastern Norway, Faculty of Health and Social Sciences, Kongsberg, Norway
| | - Richard W Harbron
- Institute of Health and Society, Newcastle University (UNEW), Newcastle upon Tyne, United Kingdom
- NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, United Kingdom
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Jordi Figuerola
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Johannes Hermen
- Luxembourg Institute of Science and Technology, Esch-sur-Alzette, Luxembourg
| | | | - Marie-Odile Bernier
- Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire d'épidémiologie des Rayonnements Ionisants, Fontenay-aux-Roses, France
| | - Magda Bosch Bosch de Basea
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Graham Byrnes
- International Agency for Research on Cancer, Lyon, France
| | - Elisabeth Cardis
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Ciber Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Michael Hauptmann
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
- Institute of BiostatisTics and Registry Research, Medical University Brandenburg Theodor Fontane, Neuruppin, Germany
| | - Neige Journy
- Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire d'épidémiologie des Rayonnements Ionisants, Fontenay-aux-Roses, France
- French National Institute of Health and Medical Research (Inserm) Unit 1018, Centre for Research in Epidemiology and Population Health (CESP), Cancer and Radiations Group, Gustave Roussy, Villejuif, France
| | | | - Johanna M Meulepas
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Roman Pokora
- Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Mainz, Germany
| | - Steven L Simon
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland
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7
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Lee KH, Lee S, Park JH, Lee SS, Kim HY, Lee WJ, Cha ES, Kim KP, Lee W, Lee JY, Lee KH. Risk of Hematologic Malignant Neoplasms From Abdominopelvic Computed Tomographic Radiation in Patients Who Underwent Appendectomy. JAMA Surg 2021; 156:343-351. [PMID: 33471110 DOI: 10.1001/jamasurg.2020.6357] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Importance Whether computed tomography (CT) radiation is truly carcinogenic remains controversial. Large epidemiological studies that purportedly showed an association between CT radiation and carcinogenesis were limited by confounding by indication and reverse causation, because the reasons for CT examination were unknown. Objective To measure the risk of hematologic malignant neoplasms associated with perioperative abdominopelvic CT radiation among patients who underwent appendectomy for acute appendicitis. Design, Setting, and Participants This nationwide population-based cohort study used the National Health Insurance Service claims database in South Korea to assess 825 820 patients who underwent appendectomy for appendicitis from January 1, 2005, to December 31, 2015, and had no underlying risk factors for cancer. Patients were divided into CT-exposed (n = 306 727) or CT-unexposed (n = 519 093) groups. The study was terminated on December 31, 2017, and data were analyzed from October 30, 2018, to September 27, 2020. Exposures Perioperative abdominopelvic CT examination from 7 days before to 7 days after appendectomy. Main Outcomes and Measures The primary outcome was the incidence rate ratio (IRR) of hematologic malignant neoplasms for both groups. The secondary outcomes were IRR of abdominopelvic organ cancers and IRR of all cancers. The lag period was 2 years for the primary outcome and 5 years for secondary outcomes. The IRRs were calculated using Poisson regression models with adjustment for age and sex. Results Among the study population of 825 820 patients (52.9% male; median age, 28 [interquartile range, 15-41] years), hematologic malignant neoplasms developed in 323 patients in the CT-exposed group during 1 486 518 person-years and 500 patients in the CT-unexposed group during 3 422 059 person-years. For all hematologic malignant neoplasms, the IRR for the CT-exposed vs CT-unexposed group was 1.26 (95% CI, 1.09-1.45; P = .002). In terms of individual categories of hematologic malignant neoplasms, the CT-exposed group had an elevated risk only for leukemia (IRR, 1.40 [98.75% CI, 1.04-1.87, adjusted by Bonferroni correction]; P = .005). There was no between-group difference in incidence rate of abdominopelvic organ cancers (IRR, 1.07 [95% CI, 1.00-1.15]; P = .06) and that of all cancers (IRR, 1.04 [95% CI, 0.99-1.09]; P = .14). Conclusions and Relevance This study controlled for reverse causation bias by defining the reasons for CT scan, and findings suggest that abdominopelvic CT radiation is associated with a higher incidence of hematologic malignant neoplasms. Efforts should be continued for judicious use of CT examinations.
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Affiliation(s)
- Kyung Hee Lee
- Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.,Department of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Korea
| | - Seungjae Lee
- Department of Applied Bioengineering, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea
| | - Ji Hoon Park
- Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.,Department of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Korea.,Department of Applied Bioengineering, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea
| | - Sung Soo Lee
- Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea
| | - Hae Young Kim
- Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea
| | - Won Jin Lee
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Eun Shil Cha
- Department of Preventive Medicine, Korea University College of Medicine, Seoul, Korea
| | - Kwang Pyo Kim
- Department of Nuclear Engineering, Kyung Hee University, Gyeonggi-do, Korea
| | - Woojoo Lee
- Department of Public Health Science, Seoul National University Graduate School of Public Health, Seoul, Korea
| | - Ji Yun Lee
- Division of Hematology-Oncology, Department of Medicine, Seoul National University Bundang Hospital, Gyeonggi-do, Korea
| | - Kyoung Ho Lee
- Department of Radiology, Seoul National University Bundang Hospital, Gyeonggi-do, Korea.,Department of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Korea.,Department of Applied Bioengineering, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Korea.,Interdisciplinary Program in Bioengineering, Seoul National University, Seoul, Korea
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8
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Cumulative Radiation Dose From Medical Imaging in Children With Noncancerous Disease. J Am Coll Radiol 2020; 17:1547-1548. [DOI: 10.1016/j.jacr.2020.05.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 11/24/2022]
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9
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Brady Z, Forsythe A, McBain-Miller J, Scurrah KJ, Smoll N, Lin Y, Lee C, Berrington de Gonzalez A, Roberts LJ, Mathews JD. Ct Dosimetry for The Australian Cohort Data Linkage Study. RADIATION PROTECTION DOSIMETRY 2020; 191:ncaa175. [PMID: 33200204 DOI: 10.1093/rpd/ncaa175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/14/2020] [Accepted: 10/03/2020] [Indexed: 06/11/2023]
Abstract
Children undergoing computed tomography (CT) scans have an increased risk of cancer in subsequent years, but it is unclear how much of the excess risk is due to reverse causation bias or confounding, rather than to causal effects of ionising radiation. An examination of the relationship between excess cancer risk and organ dose can help to resolve these uncertainties. Accordingly, we have estimated doses to 33 different organs arising from over 900 000 CT scans between 1985 and 2005 in our previously described cohort of almost 12 million Australians aged 0-19 years. We used a multi-tiered approach, starting with Medicare billing details for government-funded scans. We reconstructed technical parameters from national surveys, clinical protocols, regulator databases and peer-reviewed literature to estimate almost 28 000 000 individual organ doses. Doses were age-dependent and tended to decrease over time due to technological improvements and optimisation.
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Affiliation(s)
- Zoe Brady
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
- Department of Radiology and Nuclear Medicine, Alfred Health, Melbourne, Victoria, Australia
| | - Anna Forsythe
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Jasmine McBain-Miller
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Katrina J Scurrah
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Nicolas Smoll
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Yaqi Lin
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Amy Berrington de Gonzalez
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Leo J Roberts
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - John D Mathews
- Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
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10
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Garzón WJ, Aldana DFA, Cassola VF. PATIENT-SPECIFIC ORGAN DOSES FROM PEDIATRIC HEAD CT EXAMINATIONS. RADIATION PROTECTION DOSIMETRY 2020; 191:1-8. [PMID: 32984906 DOI: 10.1093/rpd/ncaa126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/06/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
The aim of this work was to estimate patient's organ absorbed doses from pediatric helical head computed tomography (CT) examinations using the Size-Specific Dose Estimate (SSDE) methodology and to determine organ dose to SSDE conversion coefficients for clinical routine. Patient-specific organ and tissue absorbed doses from 139 Head CT scans performed in pediatric patients from 0 to 15 years old in a Public Hospital in Tunja, Colombia were estimated. The calculations were made through Monte Carlo simulations, based on patient-specific information, dosimetric CT quantities (CTDIvol, DLP) and age-specific computational human phantoms matched to patients on the basis of gender and size. SSDE showed to be a good quantity for estimate patient-specific organ doses from pediatric head CT examinations when appropriate phantom's attenuation-based size metrics are chosen to match for any patient size. Strong correlations between absorbed dose and SSDE were found for skin (R2 = 0.99), brain (R2 = 0.98) and eyes (R2 = 0.97), respectively. Besides, a good correlation between SSDE and absorbed dose to the red bone marrow (tissue extended outside the scan coverage) was observed (R2 = 0.94). SSDE-to-organ-dose conversion coefficients obtained in this study provide a practical way to estimate patient-specific organ head CT doses.
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Affiliation(s)
- W J Garzón
- Physics Department, Pedagogical and Technological University of Colombia, Avenida Central del Norte 39-115, 150003 Tunja, Colombia
| | - D F A Aldana
- Physics Department, Pedagogical and Technological University of Colombia, Avenida Central del Norte 39-115, 150003 Tunja, Colombia
| | - V F Cassola
- Department of Nuclear Energy, Federal University of Pernambuco, Avenida Professor Luiz Freire 1000 CEP 50740-540, Recife, Pernambuco, Brazil
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11
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Pasqual E, Turner MC, Gracia-Lavedan E, Casabonne D, Benavente Y, Chef IT, Maynadié M, Cocco P, Staines A, Foretova L, Nieters A, Boffetta P, Brennan P, Cardis E, de Sanjose S. Association of ionizing radiation dose from common medical diagnostic procedures and lymphoma risk in the Epilymph case-control study. PLoS One 2020; 15:e0235658. [PMID: 32649712 PMCID: PMC7351167 DOI: 10.1371/journal.pone.0235658] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/21/2020] [Indexed: 11/19/2022] Open
Abstract
Medical diagnostic X-rays are an important source of ionizing radiation (IR) exposure in the general population; however, it is unclear if the resulting low patient doses increase lymphoma risk. We examined the association between lifetime medical diagnostic X-ray dose and lymphoma risk, taking into account potential confounding factors, including medical history. The international Epilymph study (conducted in the Czech-Republic, France, Germany, Ireland, Italy, and Spain) collected self-reported information on common diagnostic X-ray procedures from 2,362 lymphoma cases and 2,465 frequency-matched (age, sex, country) controls. Individual lifetime cumulative bone marrow (BM) dose was estimated using time period-based dose estimates for different procedures and body parts. The association between categories of BM dose and lymphoma risk was examined using unconditional logistic regression models adjusting for matching factors, socioeconomic variables, and the presence of underlying medical conditions (atopic, autoimmune, infectious diseases, osteoarthritis, having had a sick childhood, and family history of lymphoma) as potential confounders of the association. Cumulative BM dose was low (median 2.25 mGy) and was not positively associated with lymphoma risk. Odds ratios (ORs) were consistently less than 1.0 in all dose categories compared to the reference category (less than 1 mGy). Results were similar after adjustment for potential confounding factors, when using different exposure scenarios, and in analyses by lymphoma subtype and by type of control (hospital-, population-based). Overall no increased risk of lymphoma was observed. The reduced ORs may be related to unmeasured confounding or other sources of systematic bias.We found little evidence that chronic medical conditions confound lymphoma risk and medical radiation associations.
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Affiliation(s)
- Elisa Pasqual
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Michelle C. Turner
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada
| | - Esther Gracia-Lavedan
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Delphine Casabonne
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Unit of Infections and Cancer, Cancer Epidemiology Research Programme, IDIBELL, Catalan Institute of Oncology, Barcelona, Spain
| | - Yolanda Benavente
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Unit of Infections and Cancer, Cancer Epidemiology Research Programme, IDIBELL, Catalan Institute of Oncology, Barcelona, Spain
| | - Isabelle Thierry Chef
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Marc Maynadié
- Registre des Hémopathies Malignes de Côte d’Or INSERM U 1231, Université de Bourgogne Franche-Comté et CHU Dijon-Bourgogne, Dijon, France
| | - Pierluigi Cocco
- Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Cagliari, Italy
| | - Anthony Staines
- School of Nursing and Human Science, Dublin City University, Glasnevin, Dublin, Ireland
| | - Lenka Foretova
- Cancer Epidemiology and Genetics, Masaryk Memorial Cancer Institute and MF MU, Brno, Czech Republic
| | - Alexandra Nieters
- Centre of Chronic Immunodeficiency, Molecular Epidemiology, University Medical Center Freiburg, Freiburg, Germany
| | - Paolo Boffetta
- Tisch Cancer Institute and Institute for Translational Epidemiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Paul Brennan
- IARC, International Agency for Research on Cancer, Lyon, France
| | - Elisabeth Cardis
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Silvia de Sanjose
- CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Unit of Infections and Cancer, Cancer Epidemiology Research Programme, IDIBELL, Catalan Institute of Oncology, Barcelona, Spain
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12
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Daniels RD, Kendall GM, Thierry-Chef I, Linet MS, Cullings HM. Strengths and Weaknesses of Dosimetry Used in Studies of Low-Dose Radiation Exposure and Cancer. J Natl Cancer Inst Monogr 2020; 2020:114-132. [PMID: 32657346 PMCID: PMC7667397 DOI: 10.1093/jncimonographs/lgaa001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND A monograph systematically evaluating recent evidence on the dose-response relationship between low-dose ionizing radiation exposure and cancer risk required a critical appraisal of dosimetry methods in 26 potentially informative studies. METHODS The relevant literature included studies published in 2006-2017. Studies comprised case-control and cohort designs examining populations predominantly exposed to sparsely ionizing radiation, mostly from external sources, resulting in average doses of no more than 100 mGy. At least two dosimetrists reviewed each study and appraised the strengths and weaknesses of the dosimetry systems used, including assessment of sources and effects of dose estimation error. An overarching concern was whether dose error might cause the spurious appearance of a dose-response where none was present. RESULTS The review included 8 environmental, 4 medical, and 14 occupational studies that varied in properties relative to evaluation criteria. Treatment of dose estimation error also varied among studies, although few conducted a comprehensive evaluation. Six studies appeared to have known or suspected biases in dose estimates. The potential for these biases to cause a spurious dose-response association was constrained to three case-control studies that relied extensively on information gathered in interviews conducted after case ascertainment. CONCLUSIONS The potential for spurious dose-response associations from dose information appeared limited to case-control studies vulnerable to recall errors that may be differential by case status. Otherwise, risk estimates appeared reasonably free of a substantial bias from dose estimation error. Future studies would benefit from a comprehensive evaluation of dose estimation errors, including methods accounting for their potential effects on dose-response associations.
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Affiliation(s)
- Robert D Daniels
- Division of Science Integration, National Institute for Occupational Safety and Health, Cincinnati, OH
| | - Gerald M Kendall
- Cancer Epidemiology Unit, NDPH, University of Oxford, Oxford, UK
| | - Isabelle Thierry-Chef
- Barcelona Institute for Global Health, Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
- CIBER Epidemiología y Salud Pública, Madrid, Spain
| | - Martha S Linet
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Harry M Cullings
- Department of Statistics, Radiation Effects Research Foundation, Hiroshima, Japan
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13
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Lee C, Kuzmin GA, Bae J, Yao J, Mosher E, Folio LR. Automatic Mapping of CT Scan Locations on Computational Human Phantoms for Organ Dose Estimation. J Digit Imaging 2020; 32:175-182. [PMID: 30187315 DOI: 10.1007/s10278-018-0119-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
To develop an algorithm to automatically map CT scan locations of patients onto computational human phantoms to provide with patient-specific organ doses. We developed an algorithm that compares a two-dimensional skeletal mask generated from patient CTs with that of a whole body computational human phantom. The algorithm selected the scan locations showing the highest Dice Similarity Coefficient (DSC) calculated between the skeletal masks of a patient and a phantom. To test the performance of the algorithm, we randomly selected five sets of neck, chest, and abdominal CT images from the National Institutes of Health Clinical Center. We first automatically mapped scan locations of the CT images on a computational human phantom using our algorithm. We had several radiologists to manually map the same CT images on the phantom and compared the results with the automated mapping. Finally, organ doses for automated and manual mapping locations were calculated by an in-house CT dose calculator and compared to each other. The visual comparison showed excellent agreement between manual and automatic mapping locations for neck, chest, and abdomen-pelvis CTs. The difference in mapping locations averaged over the start and end in the five patients was less than 1 cm for all neck, chest, and AP scans: 0.9, 0.7, and 0.9 cm for neck, chest, and AP scans, respectively. Five cases out of ten in the neck scans show zero difference between the average manual and automatic mappings. Average of absolute dose differences between manual and automatic mappings was 2.3, 2.7, and 4.0% for neck, chest, and AP scans, respectively. The automatic mapping algorithm provided accurate scan locations and organ doses compared to manual mapping. The algorithm will be useful in cases requiring patient-specific organ dose for a large number of patients such as patient dose monitoring, clinical trials, and epidemiologic studies.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. .,Radiation Epidemiology Branch/DCEG/NCI/NIH, 9609 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Gleb A Kuzmin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jinyong Bae
- Kansas City University of Medicine and Bioscience, Kansas City, KS, USA
| | - Jianhua Yao
- Radiology and Imaging Sciences Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Elizabeth Mosher
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Les R Folio
- Radiology and Imaging Sciences Clinical Center, National Institutes of Health, Bethesda, MD, USA
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14
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Meulepas JM, Ronckers CM, Smets AMJB, Nievelstein RAJ, Gradowska P, Lee C, Jahnen A, van Straten M, de Wit MCY, Zonnenberg B, Klein WM, Merks JH, Visser O, van Leeuwen FE, Hauptmann M. Radiation Exposure From Pediatric CT Scans and Subsequent Cancer Risk in the Netherlands. J Natl Cancer Inst 2020; 111:256-263. [PMID: 30020493 DOI: 10.1093/jnci/djy104] [Citation(s) in RCA: 188] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/10/2018] [Accepted: 05/04/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Computed tomography (CT), a strong diagnostic tool, delivers higher radiation doses than most imaging modalities. As CT use has increased rapidly, radiation protection is important, particularly among children. We evaluate leukemia and brain tumor risk following exposure to low-dose ionizing radiation from CT scans in childhood. METHODS For a nationwide retrospective cohort of 168 394 children who received one or more CT scans in a Dutch hospital between 1979 and 2012 who were younger than age 18 years, we obtained cancer incidence, vital status, and confounder information by record linkage with external registries. Standardized incidence ratios were calculated using cancer incidence rates from the general Dutch population. Excess relative risks (ERRs) per 100 mGy organ dose were calculated with Poisson regression. All statistical tests were two-sided. RESULTS Standardized incidence ratios were elevated for all cancer sites. Mean cumulative bone marrow doses were 9.5 mGy at the end of follow-up, and leukemia risk (excluding myelodysplastic syndrome) was not associated with cumulative bone marrow dose (44 cases). Cumulative brain dose was on average 38.5 mGy and was statistically significantly associated with risk for malignant and nonmalignant brain tumors combined (ERR/100 mGy: 0.86, 95% confidence interval = 0.20 to 2.22, P = .002, 84 cases). Excluding tuberous sclerosis complex patients did not substantially change the risk. CONCLUSIONS We found evidence that CT-related radiation exposure increases brain tumor risk. No association was observed for leukemia. Compared with the general population, incidence of brain tumors was higher in the cohort of children with CT scans, requiring cautious interpretation of the findings.
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Affiliation(s)
- Johanna M Meulepas
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Cécile M Ronckers
- Department of Paediatric Oncology, Emma Children's Hospital, University Medical Center Utrecht, the Netherlands
| | - Anne M J B Smets
- Department of Radiology, University Medical Center Utrecht, the Netherlands
| | | | - Patrycja Gradowska
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Rockville, MD
| | - Andreas Jahnen
- Luxembourg Institute of Science and Technology (LIST), Esch-sur-Alzette, Luxembourg, the Netherlands
| | - Marcel van Straten
- Department of Radiology and Nuclear Medicine, Erasmus MC Rotterdam, the Netherlands
| | - Marie-Claire Y de Wit
- Department of Neurology and Paediatric Neurology, Erasmus MC, Sophia Children's Hospital, Rotterdam, the Netherlands
| | - Bernard Zonnenberg
- Department of Internal Medicine, University Medical Center Utrecht, the Netherlands
| | - Willemijn M Klein
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Johannes H Merks
- Department of Paediatric Oncology, Emma Children's Hospital, University Medical Center Utrecht, the Netherlands.,Academic Medical Center Amsterdam, Amsterdam, the Netherlands; Dutch Childhood Oncology Group, the Hague, the Netherlands, University Medical Center Utrecht, the Netherlands
| | - Otto Visser
- Department of Registration, Netherlands Comprehensive Cancer Organisation, Utrecht, the Netherlands
| | - Flora E van Leeuwen
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Michael Hauptmann
- Department of Epidemiology and Biostatistics, Netherlands Cancer Institute, Amsterdam, the Netherlands
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15
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Sutanto H, Irdawati Y, Anam C, Fujibuchi T, Dougherty G, Hidayanto E, Arifin Z, Soedarsono JW, Bahrudin. An artifact-free thyroid shield in CT examination: a phantom study. Biomed Phys Eng Express 2020; 6:015029. [DOI: 10.1088/2057-1976/ab6ed1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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16
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Muhammad N, Karim M, Hassan H, Kamarudin M, Wong J, Ibahim M. Estimation of effective dose and organ cancer risk from paediatric computed tomography thorax – Abdomen - Pelvis examinations. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.108438] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Lee C, Journy N, Moroz BE, Little M, Harbron R, McHugh K, Pearce M, Berrington de Gonzalez A. ORGAN DOSE ESTIMATION ACCOUNTING FOR UNCERTAINTY FOR PEDIATRIC AND YOUNG ADULT CT SCANS IN THE UNITED KINGDOM. RADIATION PROTECTION DOSIMETRY 2019; 184:44-53. [PMID: 30371899 PMCID: PMC6657815 DOI: 10.1093/rpd/ncy184] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/26/2018] [Accepted: 10/18/2018] [Indexed: 05/13/2023]
Abstract
Since our previous publication of organ dose for the pediatric CT cohort in the UK, there have been questions about the magnitude of uncertainty in our dose estimates. We therefore quantified shared and unshared uncertainties in empirical CT parameters extracted from 1073 CT films (1978-2008) from 36 hospitals in the study and propagated these uncertainties into organ doses using Monte Carlo random sampling and NCICT organ dose calculator. The average of 500 median brain and marrow doses for the full cohort was 35 (95% confidence interval: 30-40) mGy and 6 (5-7) mGy, respectively. We estimated that shared uncertainty contributed ~99% of coefficient of variation of median brain doses in brain scans compared to unshared uncertainty (1% contribution). We found that the previous brain doses were slightly underestimated for <1990 and overestimated for >1990 compared to the results in the current study due to the revised CTDI models based on CT films.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
- Corresponding author:
| | - Neige Journy
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
| | - Brian E Moroz
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
| | - Mark Little
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
| | - Richard Harbron
- Institute of Health & Society, Newcastle University, Newcastle upon Tyne, UK
| | - Kieran McHugh
- Radiology Department, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - Mark Pearce
- Institute of Health & Society, Newcastle University, Newcastle upon Tyne, UK
| | - Amy Berrington de Gonzalez
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
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18
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Behmanesh B, Keil F, Dubinski D, Won SY, Quick-Weller J, Seifert V, Gessler F. The Value of Computed Tomography Imaging of the Head After Ventriculoperitoneal Shunt Surgery in Adults. World Neurosurg 2019; 121:e159-e164. [DOI: 10.1016/j.wneu.2018.09.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
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19
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Nikkilä A, Raitanen J, Lohi O, Auvinen A. Radiation exposure from computerized tomography and risk of childhood leukemia: Finnish register-based case-control study of childhood leukemia (FRECCLE). Haematologica 2018; 103:1873-1880. [PMID: 29976736 PMCID: PMC6278981 DOI: 10.3324/haematol.2018.187716] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 06/26/2018] [Indexed: 12/31/2022] Open
Abstract
The only well-established risk factors for childhood leukemia are high-dose ionizing radiation and Down syndrome. Computerized tomography is a common source of low-dose radiation. In this study, we examined the magnitude of the risk of childhood leukemia after pediatric computed tomography examinations. We evaluated the association of computed tomography scans with risk of childhood leukemia in a nationwide register-based case-control study. Cases (n=1,093) were identified from the population-based Finnish Cancer Registry and three controls, matched by gender and age, were randomly selected for each case from the Population Registry. Information was also obtained on birth weight, maternal smoking, parental socioeconomic status and background gamma radiation. Data on computed tomography scans were collected from the ten largest hospitals in Finland, covering approximately 87% of all pediatric computed tomography scans. Red bone marrow doses were estimated with NCICT dose calculation software. The data were analyzed using exact conditional logistic regression analysis. A total of 15 cases (1.4%) and ten controls (0.3%) had undergone one or more computed tomography scans, excluding a 2-year latency period. For one or more computed tomography scans, we observed an odds ratio of 2.82 (95% confidence interval: 1.05 – 7.56). Cumulative red bone marrow dose from computed tomography scans showed an excess odds ratio of 0.13 (95% confidence interval: 0.02 – 0.26) per mGy. Our results are consistent with the notion that even low doses of ionizing radiation observably increase the risk of childhood leukemia. However, the observed risk estimates are somewhat higher than those in earlier studies, probably due to random error, although unknown predisposing factors cannot be ruled out.
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Affiliation(s)
- Atte Nikkilä
- Faculty of Medicine and Biosciences, University of Tampere
| | - Jani Raitanen
- Faculty of Social Sciences, University of Tampere.,UKK Institute for Health Promotion Research, Tampere
| | - Olli Lohi
- Faculty of Medicine and Biosciences, University of Tampere.,Tampere Center for Child Health Research, University of Tampere and Tampere University Hospital
| | - Anssi Auvinen
- Faculty of Social Sciences, University of Tampere.,UKK Institute for Health Promotion Research, Tampere.,STUK - Radiation and Nuclear Safety Authority, Helsinki, Finland
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20
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Harbron RW, Chapple CL, O'Sullivan JJ, Lee C, McHugh K, Higueras M, Pearce MS. Cancer incidence among children and young adults who have undergone x-ray guided cardiac catheterization procedures. Eur J Epidemiol 2018; 33:393-401. [PMID: 29349586 PMCID: PMC5945801 DOI: 10.1007/s10654-018-0357-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/12/2018] [Indexed: 12/11/2022]
Abstract
Children and young adults with heart disease appear to be at increased risk of developing cancer, although the reasons for this are unclear. A cohort of 11,270 individuals, who underwent cardiac catheterizations while aged ≤ 22 years in the UK, was established from hospital records. Radiation doses from cardiac catheterizations and CT scans were estimated. The cohort was matched with the NHS Central Register and NHS Transplant Registry to determine cancer incidence and transplantation status. Standardized incidence ratios (SIR) with associated confidence intervals (CI) were calculated. The excess relative risk (ERR) of lymphohaematopoietic neoplasia was also calculated using Poisson regression. The SIR was raised for all malignancies (2.32, 95% CI 1.65, 3.17), lymphoma (8.34, 95% CI 5.22, 12.61) and leukaemia (2.11, 95% CI 0.82, 4.42). After censoring transplant recipients, post-transplant, the SIR was reduced to 0.90 (95% CI 0.49, 1.49) for all malignancies. All lymphomas developed post-transplant. The SIR for all malignancies developing 5 years from the first cardiac catheterization (2 years for leukaemia/lymphoma) remained raised (3.01, 95% CI 2.09, 4.19) but was again reduced after censoring transplant recipients (0.98, 95% CI 0.48, 1.77). The ERR per mGy bone marrow dose for lymphohaematopoietic neoplasia was reduced from 0.541 (95% CI 0.104, 1.807) to 0.018 (95% CI − 0.002, 0.096) where transplantation status was accounted for as a time-dependent background risk factor. In conclusion, transplantation appears to be a large contributor to elevated cancer rates in this patient group. This is likely to be mainly due to associated immunosuppression, however, radiation exposure may also be a contributing factor.
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Affiliation(s)
- Richard W Harbron
- Institute of Health and Society, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle University, Newcastle upon Tyne, NE1 4LP, UK. .,NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, Newcastle upon Tyne, NE2 4AA, UK.
| | - Claire-Louise Chapple
- Regional Medical Physics Department, Freeman Hospital, Newcastle-upon-Tyne Hospitals NHS Trust, Newcastle upon Tyne, NE7 7DN, UK
| | - John J O'Sullivan
- Paediatric Cardiology, Freeman Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE7 7DN, UK
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kieran McHugh
- Radiology Department, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - Manuel Higueras
- Institute of Health and Society, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle University, Newcastle upon Tyne, NE1 4LP, UK.,NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, Newcastle upon Tyne, NE2 4AA, UK.,Basque Center for Applied Mathematics, Alameda de Mazarredo, 14, 48009, Bilbao, Basque Country, Spain
| | - Mark S Pearce
- Institute of Health and Society, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle University, Newcastle upon Tyne, NE1 4LP, UK.,NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards, Newcastle University, Newcastle upon Tyne, NE2 4AA, UK
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21
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Lee C, Morton LM, de Gonzalez AB. A NOVEL METHOD TO ESTIMATE LYMPHOCYTE DOSE AND APPLICATION TO PEDIATRIC AND YOUNG ADULT CT PATIENTS IN THE UNITED KINGDOM. RADIATION PROTECTION DOSIMETRY 2018; 178:116-121. [PMID: 28981878 PMCID: PMC5927330 DOI: 10.1093/rpd/ncx084] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/09/2017] [Accepted: 07/07/2017] [Indexed: 05/28/2023]
Abstract
Despite decades of epidemiological research, it remains uncertain whether ionizing radiation can cause lymphomas. Most epidemiological studies of lymphoma risk following non-uniform exposure used dose to red bone marrow (RBM), constituting a small fraction of the lymphocytes, as a surrogate of dose to the lymphocytes. We developed a method to estimate dose to the lymphocytes using the reference distribution of lymphocytes throughout the body and Monte Carlo simulations of computational human phantoms. We applied our method to estimating lymphocyte doses for a pediatric CT patient cohort in the United Kingdom. Estimated dose to the RBM was greater than lymphocyte dose for most scan types (up to 2.6-fold higher, a 5-year-old brain scan) except abdomen scan (RBM dose was about half the lymphocyte dose, a 5-year-old abdomen scan). The lymphocyte dose in the UK cohort showed that T-spine and whole body scans delivered the highest lymphocyte doses (up to 22.4 mGy).
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, USA
| | - Lindsay M Morton
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, USA
| | - Amy Berrington de Gonzalez
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, USA
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22
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Gould R, McFadden SL, Hughes CM. Radiation dose in paediatric cardiac catheterisation: A systematic literature review. Radiography (Lond) 2017; 23:358-364. [PMID: 28965901 DOI: 10.1016/j.radi.2017.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 02/01/2017] [Accepted: 02/03/2017] [Indexed: 12/23/2022]
Abstract
OBJECTIVES It is believed that children are more sensitive to ionising radiation than adults. This work reviewed the reported radiation dose estimates for paediatric cardiac catheterisation. A systematic literature review was performed by searching healthcare databases for studies reporting radiation dose using predetermined key words relating to children having cardiac catheterisation. The quality of publications was assessed using relevant Critical Appraisal Skills Programme questions and their reported radiation exposures were evaluated. KEY FINDINGS It is only in recent years that larger cohort observations have been undertaken. Although radiation dose from paediatric cardiac catheterisation has decreased in recent years, the literature indicated that it remains varied and potentially substantial. CONCLUSION Standardisation of weight categories and procedure types such as those recommended by the PiDRL project could help compare current and future radiation dose estimates.
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Affiliation(s)
- R Gould
- Institute of Nursing and Health Research, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, BT37 OQB, United Kingdom.
| | - S L McFadden
- Institute of Nursing and Health Research, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, BT37 OQB, United Kingdom
| | - C M Hughes
- Institute of Nursing and Health Research, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, BT37 OQB, United Kingdom
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23
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Khattab M, Walker DM, Albertini RJ, Nicklas JA, Lundblad LK, Vacek PM, Walker VE. Frequencies of micronucleated reticulocytes, a dosimeter of DNA double-strand breaks, in infants receiving computed tomography or cardiac catheterization. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2017; 820:8-18. [DOI: 10.1016/j.mrgentox.2017.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 12/18/2022]
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Till JE, Beck HL, Grogan HA, Caffrey EA. A review of dosimetry used in epidemiological studies considered to evaluate the linear no-threshold (LNT) dose-response model for radiation protection. Int J Radiat Biol 2017; 93:1128-1144. [DOI: 10.1080/09553002.2017.1337280] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Lubin JH, Adams MJ, Shore R, Holmberg E, Schneider AB, Hawkins MM, Robison LL, Inskip PD, Lundell M, Johansson R, Kleinerman RA, de Vathaire F, Damber L, Sadetzki S, Tucker M, Sakata R, Veiga LHS. Thyroid Cancer Following Childhood Low-Dose Radiation Exposure: A Pooled Analysis of Nine Cohorts. J Clin Endocrinol Metab 2017; 102:2575-2583. [PMID: 28323979 PMCID: PMC5505197 DOI: 10.1210/jc.2016-3529] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/02/2017] [Indexed: 12/18/2022]
Abstract
CONTEXT The increased use of diagnostic and therapeutic procedures that involve radiation raises concerns about radiation effects, particularly in children and the radiosensitive thyroid gland. OBJECTIVES Evaluation of relative risk (RR) trends for thyroid radiation doses <0.2 gray (Gy); evidence of a threshold dose; and possible modifiers of the dose-response, e.g., sex, age at exposure, time since exposure. DESIGN AND SETTING Pooled data from nine cohort studies of childhood external radiation exposure and thyroid cancer with individualized dose estimates, ≥1000 irradiated subjects or ≥10 thyroid cancer cases, with data limited to individuals receiving doses <0.2 Gy. PARTICIPANTS Cohorts included the following: childhood cancer survivors (n = 2); children treated for benign diseases (n = 6); and children who survived the atomic bombings in Japan (n = 1). There were 252 cases and 2,588,559 person-years in irradiated individuals and 142 cases and 1,865,957 person-years in nonirradiated individuals. INTERVENTION There were no interventions. MAIN OUTCOME MEASURE Incident thyroid cancers. RESULTS For both <0.2 and <0.1 Gy, RRs increased with thyroid dose (P < 0.01), without significant departure from linearity (P = 0.77 and P = 0.66, respectively). Estimates of threshold dose ranged from 0.0 to 0.03 Gy, with an upper 95% confidence bound of 0.04 Gy. The increasing dose-response trend persisted >45 years after exposure, was greater at younger age at exposure and younger attained age, and was similar by sex and number of treatments. CONCLUSIONS Our analyses reaffirmed linearity of the dose response as the most plausible relationship for "as low as reasonably achievable" assessments for pediatric low-dose radiation-associated thyroid cancer risk.
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Affiliation(s)
- Jay H. Lubin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - M. Jacob Adams
- University of Rochester School of Medicine and Dentistry, Department of Public Health Sciences, Rochester, New York 14642
| | - Roy Shore
- Radiation Effects Research Foundation, Hiroshima 732-0815, Japan
| | - Erik Holmberg
- Department of Oncology and Radiation Physics and the Oncological Centre, Sahlgrenska University Hospital, S-413-45 Goteborg, Sweden
| | - Arthur B. Schneider
- University of Illinois College of Medicine, Section of Endocrinology, Diabetes, and Metabolism, Chicago, Illinois 60612
| | - Michael M. Hawkins
- Centre for Childhood Cancer Survivor Studies, Department of Public Health and Epidemiology, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Leslie L. Robison
- Department of Epidemiology and Cancer Control, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678
| | - Peter D. Inskip
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - Marie Lundell
- Department of Medical Physics, Radiumhemmet, Karolinska University Hospital and Karolinska Institute, SE-171 76 Stockholm, Sweden
| | - Robert Johansson
- Oncology, Department of Radiation Sciences, Umeå University, 901 87 Umeå, Sweden
| | - Ruth A. Kleinerman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - Florent de Vathaire
- Cancer Epidemiology Research Unit, National Institute for Health and Medical Research–Institut Gustave Roussy, 94 805 Villejuif, France
| | - Lena Damber
- Oncology, Department of Radiation Sciences, Umeå University, 901 87 Umeå, Sweden
| | - Siegal Sadetzki
- Cancer and Radiation Epidemiology Unit, Gertner Institute, Chaim Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Tel Hashomer, 52621 Israel
| | - Margaret Tucker
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892
| | - Ritsu Sakata
- Radiation Effects Research Foundation, Hiroshima 732-0815, Japan
| | - Lene H. S. Veiga
- Institute for Radiation Protection and Dosimetry, Brazilian Nuclear Energy Commission, 22783-127 Rio de Janeiro, Brazil
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Journy NMY, Lee C, Harbron RW, McHugh K, Pearce MS, Berrington de González A. Projected cancer risks potentially related to past, current, and future practices in paediatric CT in the United Kingdom, 1990-2020. Br J Cancer 2017; 116:109-116. [PMID: 27824812 PMCID: PMC5220140 DOI: 10.1038/bjc.2016.351] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/12/2016] [Accepted: 09/25/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND To project risks of developing cancer and the number of cases potentially induced by past, current, and future computed tomography (CT) scans performed in the United Kingdom in individuals aged <20 years. METHODS Organ doses were estimated from surveys of individual scan parameters and CT protocols used in the United Kingdom. Frequencies of scans were estimated from the NHS Diagnostic Imaging Dataset. Excess lifetime risks (ELRs) of radiation-related cancer were calculated as cumulative lifetime risks, accounting for survival probabilities, using the RadRAT risk assessment tool. RESULTS In 2000-2008, ELRs ranged from 0.3 to 1 per 1000 head scans and 1 to 5 per 1000 non-head scans. ELRs per scan were reduced by 50-70% in 2000-2008 compared with 1990-1995, subsequent to dose reduction over time. The 130 750 scans performed in 2015 in the United Kingdom were projected to induce 64 (90% uncertainty interval (UI): 38-113) future cancers. Current practices would lead to about 300 (90% UI: 230-680) future cancers induced by scans performed in 2016-2020. CONCLUSIONS Absolute excess risks from single exposures would be low compared with background risks, but even small increases in annual CT rates over the next years would substantially increase the number of potential subsequent cancers.
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Affiliation(s)
- Neige M Y Journy
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, MSC 9776, Bethesda, Maryland 20892, USA
| | - Choonsik Lee
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, MSC 9776, Bethesda, Maryland 20892, USA
| | - Richard W Harbron
- Institute of Health & 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, Newcastle-upon-Tyne, UK
| | - Kieran McHugh
- Great Ormond Street Hospital for Children, Great Ormond Street, London WC1N 3JH, UK
| | - Mark S Pearce
- Institute of Health & 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, Newcastle-upon-Tyne, UK
| | - Amy Berrington de González
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, MSC 9776, Bethesda, Maryland 20892, USA
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Noriega DC, Hernández-Ramajo R, Rodríguez-Monsalve Milano F, Sanchez-Lite I, Toribio B, Ardura F, Torres R, Corredera R, Kruger A. Risk-benefit analysis of navigation techniques for vertebral transpedicular instrumentation: a prospective study. Spine J 2017; 17:70-75. [PMID: 27503262 DOI: 10.1016/j.spinee.2016.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 06/30/2016] [Accepted: 08/02/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Pedicle screws in spinal surgery have allowed greater biomechanical stability and higher fusion rates. However, malposition is very common and may cause neurologic, vascular, and visceral injuries and compromise mechanical stability. PURPOSE The purpose of this study was to compare the malposition rate between intraoperative computed tomography (CT) scan assisted-navigation and free-hand fluoroscopy-guided techniques for placement of pedicle screw instrumentation. STUDY DESIGN/SETTING This is a prospective, randomized, observational study. PATIENT SAMPLE A total of 114 patients were included: 58 in the assisted surgery group and 56 in the free-hand fluoroscopy-guided surgery group. OUTCOME MEASURES Analysis of screw position was assessed using the Heary classification. Breach severity was defined according to the Gertzbein classification. Radiation doses were evaluated using thermoluminescent dosimeters, and estimates of effective and organ doses were made based on scan technical parameters. METHODS Consecutive patients with degenerative disease, who underwent surgical procedures using the free-hand, or intraoperative navigation technique for placement of transpedicular instrumentation, were included in the study. RESULTS Forty-four out of 625 implanted screws were malpositioned: 11 (3.6%) in the navigated surgery group and 33 (10.3%) in the free-hand group (p<.001). Screw position according to the Heary scale was Grade II (4 navigated surgery, 6 fluoroscopy guided), Grade III (3 navigated surgery, 11 fluoroscopy guided), Grade IV (4 navigated surgery, 16 fluoroscopy guided), and Grade V (1 fluoroscopy guided). There was only one symptomatic case in the conventional surgery group. Breach severity was seven Grade A and four Grade B in the navigated surgery group, and eight Grade A, 24 Grade B, and one Grade C in free-hand fluoroscopy-guided surgery group. Radiation received per patient was 5.8 mSv (4.8-7.3). The median dose received in the free-hand fluoroscopy group was 1 mGy (0.8-1.1). There was no detectable radiation level in the navigation-assisted surgery group, whereas the effective dose was 10 µGy in the free-hand fluoroscopy-guided surgery group. CONCLUSIONS Malposition rate, both symptomatic and asymptomatic, in spinal surgery is reduced when using CT-guided placement of transpedicular instrumentation compared with placement under fluoroscopic guidance, with radiation values within the safety limits for health. Larger studies are needed to determine risk-benefit in these patients.
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Affiliation(s)
- David C Noriega
- Unidad de Columna, Servicio Cirugía Ortopédica, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain.
| | - Rubén Hernández-Ramajo
- Unidad de Columna, Servicio Cirugía Ortopédica, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Fiona Rodríguez-Monsalve Milano
- Unidad de Columna, Servicio Cirugía Ortopédica, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Israel Sanchez-Lite
- Servicio de Radiología, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Borja Toribio
- Servicio de Radiología, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Francisco Ardura
- Unidad de Columna, Servicio Cirugía Ortopédica, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Ricardo Torres
- Servicio de Radiofísica y Protección Radiológica, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Raul Corredera
- Unidad de Columna, Servicio Cirugía Ortopédica, Hospital Clínico Universitario de Valladolid, Calle Ramón y Cajal, 47008 Valladolid, Spain
| | - Antonio Kruger
- Center for Orthopaedics and Trauma Surgery University Hospital Giessen and Marburg GmbH, Marburg, Germany
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Power SP, Moloney F, Twomey M, James K, O’Connor OJ, Maher MM. Computed tomography and patient risk: Facts, perceptions and uncertainties. World J Radiol 2016; 8:902-915. [PMID: 28070242 PMCID: PMC5183924 DOI: 10.4329/wjr.v8.i12.902] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/29/2016] [Accepted: 10/24/2016] [Indexed: 02/06/2023] Open
Abstract
Since its introduction in the 1970s, computed tomography (CT) has revolutionized diagnostic decision-making. One of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in Japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.
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Pokora* R, Krille* L, Dreger S, Lee C, Günster C, Zeeb H, Blettner M. Computed Tomography in Germany. DEUTSCHES ARZTEBLATT INTERNATIONAL 2016; 113:721-728. [PMID: 27866569 PMCID: PMC5150210 DOI: 10.3238/arztebl.2016.0721] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 03/03/2016] [Accepted: 07/25/2016] [Indexed: 02/04/2023]
Abstract
BACKGROUND In 2001, calculations in models based on atomic bomb survivors indicated that children exposed to ionizing radiation by computed tomography (CT) would be expected to have an increased risk of cancer. This led to the issuance of new recommendations in Germany concerning CT in children. METHODS We analyzed data from the German pediatric CT cohort study together with data on children from a large general statutory health insurance provider (AOK) in order to characterize the secular trend in the use of CT in Germany. We used information from the Picture Archiving and Communication System (PACS) to estimate individual organ doses per scan and their development over time. RESULTS The number of CT scans performed on children in Germany each year declined by 29% from 2006 to 2012. Over the same period, younger children were exposed to lower organ doses during CT scanning, although some organ doses were higher in neonates than in older children. The highest organ doses were in the 7.6 to 12.5-year-old age group and affected the brain (37.12 mGy ± 19.68 mGy) and the lenses (41.24 mGy ± 20.08 mGy). In every age group, the organ doses declined from year to year. With approximately 21 000 children aged 0-13 undergoing CT each year (extrapolated from insurance data of 2008), one can expect 2.3 [-1.7; 6.3] additional new cases of leukemia and 1 [-2.3; 4.0] additional new tumor of the central nervous system to arise each year. CONCLUSION In view of the risks, children should undergo CT only for the indications listed by the German Commission on Radiological Protection (Strahlenschutzkommission). Further epidemiological studies are needed for estimation of the risk associated with the use of newer CT technology.
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Affiliation(s)
- Roman Pokora*
- *Roman Pokora and Lucian Krille are joint first authors
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), Faculty of Medicine, Johannes Gutenberg University of Mainz
| | - Lucian Krille*
- *Roman Pokora and Lucian Krille are joint first authors
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), Faculty of Medicine, Johannes Gutenberg University of Mainz
- International Agency for Research on Cancer (IARC), Lyon, France
| | - Steffen Dreger
- Leibniz Institute for Prevention Research and Epidemiology – BIPS GmbH, Bremen
| | - Choonsik Lee
- National Cancer Institute (NCI), Rockville, Maryland, USA
| | | | - Hajo Zeeb
- Leibniz Institute for Prevention Research and Epidemiology – BIPS GmbH, Bremen
- University of Bremen, Research Focus Health Sciences Bremen
| | - Maria Blettner
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), Faculty of Medicine, Johannes Gutenberg University of Mainz
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Effects of ionizing radiation on the mammalian brain. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 770:219-230. [DOI: 10.1016/j.mrrev.2016.08.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 11/21/2022]
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31
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Jansen JTM, Shrimpton PC. Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT. Phys Med Biol 2016; 61:5356-77. [DOI: 10.1088/0031-9155/61/14/5356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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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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Berger RP, Panigrahy A, Gottschalk S, Sheetz M. Effective Radiation Dose in a Skeletal Survey Performed for Suspected Child Abuse. J Pediatr 2016; 171:310-2. [PMID: 26831745 DOI: 10.1016/j.jpeds.2016.01.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 12/10/2015] [Accepted: 01/05/2016] [Indexed: 11/26/2022]
Abstract
Effective dose of a skeletal survey in infants using digital radiography was estimated to be 0.2 mSv using Monte Carlo simulation. Radiation risk from this procedure is, therefore, low. Radiation concern should not be an overriding factor when deciding whether skeletal survey is needed in cases of possible physical abuse.
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Affiliation(s)
- Rachel P Berger
- Department of Pediatrics, Children's Hospital of Pittsburgh of the University of Pittsburgh Medical Center, Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA.
| | - Ashok Panigrahy
- Department Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA
| | - Shawn Gottschalk
- Department Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA
| | - Michael Sheetz
- Department of Radiation Safety, University of Pittsburgh, Pittsburgh, PA
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Portelli JL, McNulty JP, Bezzina P, Rainford L. Frequency of paediatric medical imaging examinations performed at a European teaching hospital over a 7-year period. Eur Radiol 2016; 26:4221-4230. [DOI: 10.1007/s00330-016-4305-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 02/18/2016] [Accepted: 02/23/2016] [Indexed: 11/24/2022]
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Kitahara CM, Linet MS, Rajaraman P, Ntowe E, Berrington de González A. A New Era of Low-Dose Radiation Epidemiology. Curr Environ Health Rep 2016; 2:236-49. [PMID: 26231501 DOI: 10.1007/s40572-015-0055-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The last decade has introduced a new era of epidemiologic studies of low-dose radiation facilitated by electronic record linkage and pooling of cohorts that allow for more direct and powerful assessments of cancer and other stochastic effects at doses below 100 mGy. Such studies have provided additional evidence regarding the risks of cancer, particularly leukemia, associated with lower-dose radiation exposures from medical, environmental, and occupational radiation sources, and have questioned the previous findings with regard to possible thresholds for cardiovascular disease and cataracts. Integrated analysis of next generation genomic and epigenetic sequencing of germline and somatic tissues could soon propel our understanding further regarding disease risk thresholds, radiosensitivity of population subgroups and individuals, and the mechanisms of radiation carcinogenesis. These advances in low-dose radiation epidemiology are critical to our understanding of chronic disease risks from the burgeoning use of newer and emerging medical imaging technologies, and the continued potential threat of nuclear power plant accidents or other radiological emergencies.
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Affiliation(s)
- Cari M Kitahara
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, 9609 Medical Center Drive, Rm 7E566, Rockville, MD, 20850, USA,
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Takahashi F, Sato K, Endo A, Ono K, Ban N, Hasegawa T, Katsunuma Y, Yoshitake T, Kai M. Numerical Analysis of Organ Doses Delivered During Computed Tomography Examinations Using Japanese Adult Phantoms with the WAZA-ARI Dosimetry System. HEALTH PHYSICS 2015; 109:104-112. [PMID: 26107430 DOI: 10.1097/hp.0000000000000299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A dosimetry system for computed tomography (CT) examinations, named WAZA-ARI, is being developed to accurately assess radiation doses to patients in Japan. For dose calculations in WAZA-ARI, organ doses were numerically analyzed using average adult Japanese male (JM) and female (JF) phantoms with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the photon energy distribution of emitted photons and dose profiles on the table for some multi-detector row CT (MDCT) devices. Numerical analyses using a source model in PHITS could specifically take into account emissions of x rays from the tube to the table with attenuation of photons through a beam-shaping filter for each MDCT device based on the experiment results. The source model was validated by measuring the CT dose index (CTDI). Numerical analyses with PHITS revealed a concordance of organ doses with body sizes of the JM and JF phantoms. The organ doses in the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculations in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model (THRA1 phantom). The results imply that numerical analyses using the Japanese phantoms and specified source models can give reasonable estimates of dose for MDCT devices for typical Japanese adults.
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Affiliation(s)
- Fumiaki Takahashi
- *Japan Atomic Energy Agency, †Tokyo Healthcare University, ‡Tokai University Oiso Hospital, §Tokai University Hospital, **Shin-Beppu Hospital, ††Oita University of Nursing and Health Sciences
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Abstract
Recent record-linkage studies of cancer risk following computed tomography (CT) procedures among children and adolescents under 21 years of age must be interpreted with caution. The reasons why the examinations were performed were not known, and the dosimetric approaches did not include individual dose reconstructions or account for the possibility for missed examinations. The recent report (2013) on children by the United Nations Scientific Committee on the Effects of Atomic Radiation concluded that the associations may have resulted from confounding by indication (also called 'reverse causation'), and not radiation exposure. The reported cancer associations may very well have been related to the patients' underlying health conditions that prompted the examinations. Reverse causation has been observed in other epidemiological investigations, such as a Swedish study of thyroid cancer risk following I-131 scintillation imaging scans, and in studies of brain cancer risk following Thorotrast for cerebral angiography. Epidemiological patterns reported in the CT studies were also inconsistent with the world's literature. For example, in a UK study, teenagers had a higher risk of brain tumour than young children; in an Australian study, cancers not previously linked to radiation were significantly elevated; and in a Taiwanese study, the risk of benign tumours decreased with age at the time of CT examination. In all studies, solid tumours appeared much earlier than previously reported. Remarkably, in the Australian study, brain cancer excesses were seen regardless of whether or not the CT was to the head, i.e. a significant excess was reported for CT examinations of the abdomen and extremities, which involved no radiation exposure to the brain. In the UK study, the significance of the 'leukaemia' finding was only because myelodysplastic syndrome was added to the category, and there was no significance for leukaemia alone. Without knowledge of why CT examinations were performed, any future studies will be equally difficult to interpret. It is noteworthy that two recent studies of children in France and Germany found no significant excess cancer risk from CT scans once adjustment was made for conditions that prompted the scan, family history, or other predisposing factors known to be associated with increased cancer risk. Nonetheless, such studies have heightened awareness of these relatively high-dose diagnostic procedures, and the need to reduce unnecessary examinations and lower the dose per examination commensurate with the desired image quality.
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Affiliation(s)
- J D Boice
- Department of Medicine and Vanderbilt-Ingram Cancer Centre, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN 37232, USA
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Krille L, Dreger S, Schindel R, Albrecht T, Asmussen M, Barkhausen J, Berthold JD, Chavan A, Claussen C, Forsting M, Gianicolo EAL, Jablonka K, Jahnen A, Langer M, Laniado M, Lotz J, Mentzel HJ, Queißer-Wahrendorf A, Rompel O, Schlick I, Schneider K, Schumacher M, Seidenbusch M, Spix C, Spors B, Staatz G, Vogl T, Wagner J, Weisser G, Zeeb H, Blettner M. Risk of cancer incidence before the age of 15 years after exposure to ionising radiation from computed tomography: results from a German cohort study. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2015; 54:1-12. [PMID: 25567615 DOI: 10.1007/s00411-014-0580-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 12/12/2014] [Indexed: 06/04/2023]
Abstract
The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates.
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Affiliation(s)
- L Krille
- Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Obere Zahlbacher Straße 69, 55131, Mainz, Germany
- International Agency for Research on Cancer, 69372, Lyon, France
| | - S Dreger
- Leibniz - Institute for Prevention Research and Epidemiology - BIPS, Research Focus Health Sciences Bremen, University of Bremen, 28359, Bremen, Germany
| | - R Schindel
- Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Obere Zahlbacher Straße 69, 55131, Mainz, Germany
| | - T Albrecht
- Institut für Radiologie und Interventionelle Therapie, Vivantes, Klinikum Neukölln, 12351, Berlin, Germany
| | - M Asmussen
- Städtisches Klinikum Karlsruhe, Zentralinstitut für Bildgebende Diagnostik, 76133, Karlsruhe, Germany
| | - J Barkhausen
- Klinik für Radiologie und Nuklearmedizin, Campus Lübeck, Universitätsklinikum Schleswig Holstein, 23538, Lübeck, Germany
| | - J D Berthold
- Institut für Diagnostische und Interventionelle Radiologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - A Chavan
- Institut für Diagnostische & Interventionelle Radiologie, Klinikum Oldenburg GmbH, 26133, Oldenburg, Germany
| | - C Claussen
- Abt. für Diagnostische und Interventionelle Radiologie, Universitätsklinikum Tübingen, 72076, Tübingen, Germany
| | - M Forsting
- Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Universitätsklinikum Essen, 45147, Essen, Germany
| | - E A L Gianicolo
- Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Obere Zahlbacher Straße 69, 55131, Mainz, Germany
- Institute of Clinical Physiology, National Research Council, 73100, Lecce, Italy
| | - K Jablonka
- Klinik für Radiologische Diagnostik und Nuklearmedizin, Klinikum Bremen-Mitte, 28177, Bremen, Germany
| | - A Jahnen
- Centre de Recherche Public Henri Tudor, 1855, Luxembourg, Luxembourg
| | - M Langer
- Klinik für Radiologie, Universitätsklinikum Freiburg, 79106, Freiburg, Germany
| | - M Laniado
- Institut und Poliklinik für Radiologische Diagnostik, Universitätsklinikum Carl Gustav Carus Dresden, 01307, Dresden, Germany
| | - J Lotz
- Institut für Diagnostische und Interventionelle Radiologie, Universitätsmedizin Göttingen, 37075, Göttingen, Germany
| | - H J Mentzel
- Institut für Diagnostische und Interventionelle Radiologie, Sektion Kinderradiologie, Universitätsklinikum Jena, 07740, Jena, Germany
| | - A Queißer-Wahrendorf
- Zentrum für Kinder- und Jugendmedizin, Universitätsmedizin Mainz, 55131, Mainz, Germany
| | - O Rompel
- Radiologisches Institut, Universitätsklinikum Erlangen, 91054, Erlangen, Germany
| | - I Schlick
- Institut für Radiologie und Neuroradiologie, Klinikum Nürnberg Süd, 90471, Nuremberg, Germany
| | - K Schneider
- Klinikum der Universität München, Dr. von Haunersches Kinderspital, Institut für Klinische Radiologie, 80337, Munich, Germany
| | - M Schumacher
- Klinik für Neuroradiologie, Neurozentrum, Universitätsklinik Freiburg, 78106, Freiburg, Germany
| | - M Seidenbusch
- Klinikum der Universität München, Dr. von Haunersches Kinderspital, Institut für Klinische Radiologie, 80337, Munich, Germany
| | - C Spix
- German Childhood Cancer Registry, University Medical Center Mainz, 55131, Mainz, Germany
| | - B Spors
- Kinderradiologie, Standort Campus Virchow Klinikum, Charité - Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - G Staatz
- Klinik und Poliklinik für diagnostische und interventionelle Radiologie, Sektion Kinderradiologie, Universitätsmedizin Mainz, 55131, Mainz, Germany
| | - T Vogl
- Institut für Diagnostische und Interventionelle Radiologie, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt/Main, 60590, Frankfurt, Germany
| | - J Wagner
- Institut für Radiologie und Interventionelle Therapie, Vivantes, Klinikum im Friedrichshain, 10249, Berlin, Germany
| | - G Weisser
- Institut für Klinische Radiologie und Nuklearmedizin, Universitätsklinikum Mannheim, 68167, Mannheim, Germany
| | - H Zeeb
- Leibniz - Institute for Prevention Research and Epidemiology - BIPS, Research Focus Health Sciences Bremen, University of Bremen, 28359, Bremen, Germany
| | - M Blettner
- Institute of Medical Biostatistics, Epidemiology and Informatics, University Medical Center Mainz, Obere Zahlbacher Straße 69, 55131, Mainz, Germany.
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McNally JS, McLaughlin MS, Hinckley PJ, Treiman SM, Stoddard GJ, Parker DL, Treiman GS. Intraluminal thrombus, intraplaque hemorrhage, plaque thickness, and current smoking optimally predict carotid stroke. Stroke 2014; 46:84-90. [PMID: 25406146 DOI: 10.1161/strokeaha.114.006286] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND PURPOSE Intraplaque hemorrhage (IPH) is associated with acute and future stroke. IPH is also associated with lumen markers of stroke risk including stenosis, plaque thickness, and ulceration. Whether IPH adds further predictive value to these other variables is unknown. The purpose of this study was to determine whether IPH improves carotid-source stroke prediction. METHODS In this retrospective cross-sectional study, patients undergoing stroke workup were imaged with MRI and IPH detection. Seven hundred twenty-six carotid-brain image pairs were analyzed after excluding vessels with noncarotid plaque stroke sources (420) and occlusions (7) or near-occlusions (3). Carotid imaging characteristics were recorded, including percent diameter and mm stenosis, plaque thickness, ulceration, intraluminal thrombus, and IPH. Clinical confounders were recorded, and a multivariable logistic regression model was fitted. Backward elimination was used to determine essential carotid-source stroke predictors with a threshold 2-sided P<0.10. Receiver operating characteristic analysis was performed to determine discriminatory value. RESULTS Significant predictors of carotid-source stroke included intraluminal thrombus (odds ratio=103.6; P<0.001), IPH (odds ratio=25.2; P<0.001), current smoking (odds ratio=2.78; P=0.004), and thickness (odds ratio=1.24; P=0.020). The final model discriminatory value was excellent (area under the curve=0.862). This was significantly higher than the final model without IPH (area under the curve=0.814), or models using only stenosis as a continuous variable (area under the curve=0.770) or cutoffs of 50% and 70% (area under the curve=0.669), P<0.001. CONCLUSIONS After excluding patients with noncarotid plaque stroke sources, optimal discrimination of carotid-source stroke was obtained with intraluminal thrombus, IPH, plaque thickness, and smoking history but not ulceration and stenosis.
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Affiliation(s)
- J Scott McNally
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.).
| | - Michael S McLaughlin
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
| | - Peter J Hinckley
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
| | - Scott M Treiman
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
| | - Gregory J Stoddard
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
| | - Dennis L Parker
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
| | - Gerald S Treiman
- From the Utah Center for Advanced Imaging Research, Department of Radiology (J.S.M., M.S.M., P.J.H., S.M.T., D.L.P., G.S.T.), Study Design and Biostatistics Center, Department of Orthopedics (G.J.S.), and Department of Surgery (G.S.T.), University of Utah, Salt Lake City; and Department of Surgery, VA Salt Lake City Health Care System, UT (G.S.T.)
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Lee E, Lamart S, Little MP, Lee C. Database of normalised computed tomography dose index for retrospective CT dosimetry. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2014; 34:363-88. [PMID: 24727361 PMCID: PMC10775015 DOI: 10.1088/0952-4746/34/2/363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Volumetric computed tomography dose index (CTDIvol) is an important dose descriptor to reconstruct organ doses for patients combined with the organ dose calculated from computational human phantoms coupled with Monte Carlo transport techniques. CTDIvol can be derived from weighted CTDI (CTDIw) normalised to the tube current-time product (mGy/100 mAs), using knowledge of tube current-time product (mAs), tube potential (kVp), type of CTDI phantoms (head or body), and pitch. The normalised CTDIw is one of the characteristics of a CT scanner but not readily available from the literature. In the current study, we established a comprehensive database of normalised CTDIw values based on multiple data sources: the ImPACT dose survey from the United Kingdom, the CT-Expo dose calculation program, and surveys performed by the US Food and Drug Administration (FDA) and the National Lung Screening Trial (NLST). From the sources, the CTDIw values for a total of 68, 138, 30, and 13 scanner model groups were collected, respectively. The different scanner groups from the four data sources were sorted and merged into 162 scanner groups for eight manufacturers including General Electric (GE), Siemens, Philips, Toshiba, Elscint, Picker, Shimadzu, and Hitachi. To fill in missing CTDI values, a method based on exponential regression analysis was developed based on the existing data. Once the database was completed, two different analyses of data variability were performed. First, we averaged CTDI values for each scanner in the different data sources and analysed the variability of the average CTDI values across the different scanner models within a given manufacturer. Among the four major manufacturers, Toshiba and Philips showed the greatest coefficient of variation (COV) (=standard deviation/mean) for the head and body normalised CTDIw values, 39% and 54%, respectively. Second, the variation across the different data sources was analysed for CT scanners where more than two data sources were involved. The CTDI values for the scanners from Siemens showed the greatest variation across the data sources, being about four times greater than the variation of Toshiba scanners. The established CTDI database will be used for the reconstruction of CTDIvol and then the estimation of individualised organ doses for retrospective patient cohorts in epidemiologic studies.
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Affiliation(s)
- Eunah Lee
- Radiation Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD 20852, USA
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Leukemia and brain tumors among children after radiation exposure from CT scans: design and methodological opportunities of the Dutch Pediatric CT Study. Eur J Epidemiol 2014; 29:293-301. [DOI: 10.1007/s10654-014-9900-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 04/04/2014] [Indexed: 10/25/2022]
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Candela-Juan C, Montoro A, Ruiz-Martínez E, Villaescusa JI, Martí-Bonmatí L. Current knowledge on tumour induction by computed tomography should be carefully used. Eur Radiol 2013; 24:649-56. [PMID: 24281269 DOI: 10.1007/s00330-013-3047-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 09/24/2013] [Accepted: 10/01/2013] [Indexed: 10/26/2022]
Abstract
Risks associated to ionising radiation from medical imaging techniques have focused the attention of the medical society and general population. This risk is aimed to determine the probability that a tumour is induced as a result of a computed tomography (CT) examination since it makes nowadays the biggest contribution to the collective dose. Several models of cancer induction have been reported in the literature, with diametrically different implications. This article reviews those models, focusing on the ones used by the scientific community to estimate CT detriments. Current estimates of the probability that a CT examination induces cancer are reported, highlighting its low magnitude (near the background level) and large sources of uncertainty. From this objective review, it is concluded that epidemiological data with more accurate dosimetric estimates are needed. Prediction of the number of tumours that will be induced in population exposed to ionising radiation should be avoided or, if given, it should be accompanied by a realistic evaluation of its uncertainty and of the advantages of CTs. Otherwise they may have a negative impact in both the medical community and the patients. Reducing doses even more is not justified if that compromises clinical image quality in a necessary investigation. Key Points • Predictions of radiation-induced cancer should be discussed alongside benefits of imaging. • Estimates of induced cancers have noticeable uncertainties that should always be highlighted. • There is controversy about the acceptance of the linear no-threshold model. • Estimated extra risks of cancer are close to the background level. • Patients should not be alarmed by potential cancer induction by CT examinations.
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Affiliation(s)
- Cristian Candela-Juan
- Radioprotection Department, La Fe University and Polytechnic Hospital, Valencia, 46026, Spain,
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Abstract
Many assumptions are made when imaging children. In particular a judgement is made regarding how safe or unsafe each imaging modality is, using relatively arbitrary definitions and distinctions, due to the lack of robust scientific data. Here, the latest evidence is reviewed, particularly regarding the medical exposure to ionizing radiation (X-rays and CT) and MRI in childhood. The best evidence currently available suggests a small but convincing risk of cumulative low-dose ionizing radiation in children. Given our predictions for the children imaged today, it seems reasonable to pursue non-ionizing-based techniques wherever possible, although there is emerging evidence that MRI and ultrasound may have hitherto unknown effects. As our knowledge base expands, we must continually review our practice in light of the latest scientific data.
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Affiliation(s)
| | - Alvhild Alette Bj⊘rkum
- Departments of Biomedical Laboratory
Sciences and Chemical Engineering, Faculty of Engineering, Bergen University
College, Bergen, Norway
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Cohen M. Cancer risks from CT radiation: is there a dose threshold? J Am Coll Radiol 2013; 10:817-9. [PMID: 24044952 DOI: 10.1016/j.jacr.2013.03.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 03/01/2013] [Indexed: 11/16/2022]
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Mathews JD, Forsythe AV, Brady Z, Butler MW, Goergen SK, Byrnes GB, Giles GG, Wallace AB, Anderson PR, Guiver TA, McGale P, Cain TM, Dowty JG, Bickerstaffe AC, Darby SC. Cancer risk in 680,000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians. BMJ 2013; 346:f2360. [PMID: 23694687 PMCID: PMC3660619 DOI: 10.1136/bmj.f2360] [Citation(s) in RCA: 1302] [Impact Index Per Article: 118.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans. DESIGN Population based, cohort, data linkage study in Australia. COHORT MEMBERS: 10.9 million people identified from Australian Medicare records, aged 0-19 years on 1 January 1985 or born between 1 January 1985 and 31 December 2005; all exposures to CT scans funded by Medicare during 1985-2005 were identified for this cohort. Cancers diagnosed in cohort members up to 31 December 2007 were obtained through linkage to national cancer records. MAIN OUTCOME Cancer incidence rates in individuals exposed to a CT scan more than one year before any cancer diagnosis, compared with cancer incidence rates in unexposed individuals. RESULTS 60,674 cancers were recorded, including 3150 in 680,211 people exposed to a CT scan at least one year before any cancer diagnosis. The mean duration of follow-up after exposure was 9.5 years. Overall cancer incidence was 24% greater for exposed than for unexposed people, after accounting for age, sex, and year of birth (incidence rate ratio (IRR) 1.24 (95% confidence interval 1.20 to 1.29); P<0.001). We saw a dose-response relation, and the IRR increased by 0.16 (0.13 to 0.19) for each additional CT scan. The IRR was greater after exposure at younger ages (P<0.001 for trend). At 1-4, 5-9, 10-14, and 15 or more years since first exposure, IRRs were 1.35 (1.25 to 1.45), 1.25 (1.17 to 1.34), 1.14 (1.06 to 1.22), and 1.24 (1.14 to 1.34), respectively. The IRR increased significantly for many types of solid cancer (digestive organs, melanoma, soft tissue, female genital, urinary tract, brain, and thyroid); leukaemia, myelodysplasia, and some other lymphoid cancers. There was an excess of 608 cancers in people exposed to CT scans (147 brain, 356 other solid, 48 leukaemia or myelodysplasia, and 57 other lymphoid). The absolute excess incidence rate for all cancers combined was 9.38 per 100,000 person years at risk, as of 31 December 2007. The average effective radiation dose per scan was estimated as 4.5 mSv. CONCLUSIONS The increased incidence of cancer after CT scan exposure in this cohort was mostly due to irradiation. Because the cancer excess was still continuing at the end of follow-up, the eventual lifetime risk from CT scans cannot yet be determined. Radiation doses from contemporary CT scans are likely to be lower than those in 1985-2005, but some increase in cancer risk is still likely from current scans. Future CT scans should be limited to situations where there is a definite clinical indication, with every scan optimised to provide a diagnostic CT image at the lowest possible radiation dose.
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Affiliation(s)
- John D Mathews
- School of Population and Global Health, University of Melbourne, Carlton, Vic 3053, Australia
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Assessing organ doses from paediatric CT scans--a novel approach for an epidemiology study (the EPI-CT study). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:717-28. [PMID: 23429160 PMCID: PMC3635173 DOI: 10.3390/ijerph10020717] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/30/2013] [Accepted: 01/31/2013] [Indexed: 11/17/2022]
Abstract
The increasing worldwide use of paediatric computed tomography (CT) has led to increasing concerns regarding the subsequent effects of exposure to radiation. In response to this concern, the international EPI-CT project was developed to study the risk of cancer in a large multi-country cohort. In radiation epidemiology, accurate estimates of organ-specific doses are essential. In EPI-CT, data collection is split into two time periods—before and after introduction of the Picture Archiving Communication System (PACS) introduced in the 1990s. Prior to PACS, only sparse information about scanner settings is available from radiology departments. Hence, a multi-level approach was developed to retrieve information from a questionnaire, surveys, scientific publications, and expert interviews. For the years after PACS was introduced, scanner settings will be extracted from Digital Imaging and Communications in Medicine (DICOM) headers, a protocol for storing medical imaging data. Radiation fields and X-ray interactions within the body will be simulated using phantoms of various ages and Monte-Carlo-based radiation transport calculations. Individual organ doses will be estimated for each child using an accepted calculation strategy, scanner settings, and the radiation transport calculations. Comprehensive analyses of missing and uncertain dosimetry data will be conducted to provide uncertainty distributions of doses.
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Kortesniemi M, Salli E, Seuri R. Organ dose calculation in CT based on scout image data and automatic image registration. Acta Radiol 2012; 53:908-13. [PMID: 22919053 DOI: 10.1258/ar.2012.110611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Computed tomography (CT) has become the main contributor of the cumulative radiation exposure in radiology. Information on cumulative exposure history of the patient should be available for efficient management of radiation exposures and for radiological justification. PURPOSE To develop and evaluate automatic image registration for organ dose calculation in CT. MATERIAL AND METHODS Planning radiograph (scout) image data describing CT scan ranges from 15 thoracic CT examinations (9 men and 6 women) and 10 abdominal CT examinations (6 men and 4 women) were co-registered with the reference trunk CT scout image. 2-D affine transformation and normalized correlation metric was used for image registration. Longitudinal (z-axis) scan range coordinates on the reference scout image were converted into slice locations on the CT-Expo anthropomorphic male and female models, following organ and effective dose calculations. RESULTS The average deviation of z-location of studied patient images from the corresponding location in the reference scout image was 6.2 mm. The ranges of organ and effective doses with constant exposure parameters were from 0 to 28.0 mGy and from 7.3 to 14.5 mSv, respectively. The mean deviation of the doses for fully irradiated organs (inside the scan range), partially irradiated organs and non-irradiated organs (outside the scan range) was 1%, 5%, and 22%, respectively, due to image registration. CONCLUSION The automated image processing method to registrate individual chest and abdominal CT scout radiograph with the reference scout radiograph is feasible. It can be used to determine the individual scan range coordinates in z-direction to calculate the organ dose values. The presented method could be utilized in automatic organ dose calculation in CT for radiation exposure tracking of the patients.
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Affiliation(s)
- Mika Kortesniemi
- HUS Helsinki Medical Imaging Center, University of Helsinki, Finland
| | - Eero Salli
- HUS Helsinki Medical Imaging Center, University of Helsinki, Finland
| | - Raija Seuri
- HUS Helsinki Medical Imaging Center, University of Helsinki, Finland
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Pearce MS, Salotti JA, Little MP, McHugh K, Lee C, Kim KP, Howe NL, Ronckers CM, Rajaraman P, Sir Craft AW, Parker L, Berrington de González A. Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. Lancet 2012; 380:499-505. [PMID: 22681860 PMCID: PMC3418594 DOI: 10.1016/s0140-6736(12)60815-0] [Citation(s) in RCA: 2481] [Impact Index Per Article: 206.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Although CT scans are very useful clinically, potential cancer risks exist from associated ionising radiation, in particular for children who are more radiosensitive than adults. We aimed to assess the excess risk of leukaemia and brain tumours after CT scans in a cohort of children and young adults. METHODS In our retrospective cohort study, we included patients without previous cancer diagnoses who were first examined with CT in National Health Service (NHS) centres in England, Wales, or Scotland (Great Britain) between 1985 and 2002, when they were younger than 22 years of age. We obtained data for cancer incidence, mortality, and loss to follow-up from the NHS Central Registry from Jan 1, 1985, to Dec 31, 2008. We estimated absorbed brain and red bone marrow doses per CT scan in mGy and assessed excess incidence of leukaemia and brain tumours cancer with Poisson relative risk models. To avoid inclusion of CT scans related to cancer diagnosis, follow-up for leukaemia began 2 years after the first CT and for brain tumours 5 years after the first CT. FINDINGS During follow-up, 74 of 178,604 patients were diagnosed with leukaemia and 135 of 176,587 patients were diagnosed with brain tumours. We noted a positive association between radiation dose from CT scans and leukaemia (excess relative risk [ERR] per mGy 0·036, 95% CI 0·005-0·120; p=0·0097) and brain tumours (0·023, 0·010-0·049; p<0·0001). Compared with patients who received a dose of less than 5 mGy, the relative risk of leukaemia for patients who received a cumulative dose of at least 30 mGy (mean dose 51·13 mGy) was 3·18 (95% CI 1·46-6·94) and the relative risk of brain cancer for patients who received a cumulative dose of 50-74 mGy (mean dose 60·42 mGy) was 2·82 (1·33-6·03). INTERPRETATION Use of CT scans in children to deliver cumulative doses of about 50 mGy might almost triple the risk of leukaemia and doses of about 60 mGy might triple the risk of brain cancer. Because these cancers are relatively rare, the cumulative absolute risks are small: in the 10 years after the first scan for patients younger than 10 years, one excess case of leukaemia and one excess case of brain tumour per 10,000 head CT scans is estimated to occur. Nevertheless, although clinical benefits should outweigh the small absolute risks, radiation doses from CT scans ought to be kept as low as possible and alternative procedures, which do not involve ionising radiation, should be considered if appropriate. FUNDING US National Cancer Institute and UK Department of Health.
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Affiliation(s)
- Mark S Pearce
- Institute of Health and Society, Newcastle University, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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Pearce MS, Salotti JA, McHugh K, Kim KP, Craft AW, Lubin J, Ron E, Parker L. Socio-economic variation in CT scanning in Northern England, 1990-2002. BMC Health Serv Res 2012; 12:24. [PMID: 22283843 PMCID: PMC3276411 DOI: 10.1186/1472-6963-12-24] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 01/27/2012] [Indexed: 01/01/2023] Open
Abstract
Background Socio-economic status is known to influence health throughout life. In childhood, studies have shown increased injury rates in more deprived settings. Socio-economic status may therefore be related to rates of certain medical procedures, such as computed tomography (CT) scans. This study aimed to assess socio-economic variation among young people having CT scans in Northern England between 1990 and 2002 inclusive. Methods Electronic data were obtained from Radiology Information Systems of all nine National Health Service hospital Trusts in the region. CT scan data, including sex, date of scan, age at scan, number and type of scans were assessed in relation to quintiles of Townsend deprivation scores, obtained from linkage of postcodes with census data, using χ2 tests and Spearman rank correlations. Results During the study period, 39,676 scans were recorded on 21,089 patients, with 38,007 scans and 19,485 patients (11344 male and 8132 female) linkable to Townsend scores. The overall distributions of both scans and patients by quintile of Townsend deprivation scores were significantly different to the distributions of Townsend scores from the census wards included in the study (p < 0.0001). There was a significant association between type of scan and deprivation quintile (p < 0.0001), primarily due to the higher proportions of head scans in the three most deprived quintiles, and slightly higher proportions of chest scans and abdomen and pelvis scans in the least deprived groups. There was also a significant association (p < 0.0001) between the patient's age at the time of the CT scan and Townsend deprivation quintiles, with slightly increasing proportions of younger children with increasing deprivation. A similar association with age (p < 0.0001) was seen when restricting the data to include only the first scan of each patient. The number of scans per patient was also associated with Townsend deprivation quintiles (p = 0.014). Conclusions Social inequalities exist in the numbers of young people undergoing CT scans with those from deprived areas more likely to do so. This may reflect the rates of injuries in these individuals and implies that certain groups within the population may receive higher radiation doses than others due to medical procedures.
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Affiliation(s)
- Mark S Pearce
- Institute of Health and Society, Newcastle University, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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