The European EPI-CT study aims to quantify cancer risks from CT examinations of children and young adults. Here, we assess the risk of brain cancer.
We pooled data from nine European countries for ...this cohort study. Eligible participants had at least one CT examination before age 22 years documented between 1977 and 2014, had no previous diagnosis of cancer or benign brain tumour, and were alive and cancer-free at least 5 years after the first CT. Participants were identified through the Radiology Information System in 276 hospitals. Participants were linked with national or regional registries of cancer and vital status, and eligible cases were patients with brain cancers according to WHO International Classification of Diseases for Oncology. Gliomas were analysed separately to all brain cancers. Organ doses were reconstructed using historical machine settings and a large sample of CT images. Excess relative risks (ERRs) of brain cancer per 100 mGy of cumulative brain dose were calculated with linear dose-response modelling. The outcome was the first reported diagnosis of brain cancer after an exclusion period of 5 years after the first electronically recorded CT examination.
We identified 948 174 individuals, of whom 658 752 (69%) were eligible for our study. 368 721 (56%) of 658 752 participants were male and 290 031 (44%) were female. During a median follow-up of 5·6 years (IQR 2·4–10·1), 165 brain cancers occurred, including 121 (73%) gliomas. Mean cumulative brain dose, lagged by 5 years, was 47·4 mGy (SD 60·9) among all individuals and 76·0 mGy (100·1) among people with brain cancer. A significant linear dose-response relationship was observed for all brain cancers (ERR per 100 mGy 1·27 95% CI 0·51–2·69) and for gliomas separately (ERR per 100 mGy 1·11 0·36–2·59). Results were robust when the start of follow-up was delayed beyond 5 years and when participants with possibly previously unreported cancers were excluded.
The observed significant dose-response relationship between CT-related radiation exposure and brain cancer in this large, multicentre study with individual dose evaluation emphasises careful justification of paediatric CTs and use of doses as low as reasonably possible.
EU FP7; Belgian Cancer Registry; La Ligue contre le Cancer, L'Institut National du Cancer, France; Ministry of Health, Labour and Welfare of Japan; German Federal Ministry of Education and Research; Worldwide Cancer Research; Dutch Cancer Society; Research Council of Norway; Consejo de Seguridad Nuclear, Generalitat de Catalunya, Spain; US National Cancer Institute; UK National Institute for Health Research; Public Health England.
Abstract Background Interventional cardiologists (ICs) are exposed to X-rays and may be at risk to develop cataract earlier than common senile cataract. Excess risk of posterior subcapsular cataract, ...known as radiation-induced, was previously observed in samples of ICs from Malaysia, and Latin America. The O'CLOC study (Occupational Cataracts and Lens Opacities in interventional Cardiology) was performed to quantify the risk at the scale of France. Methods This cross-sectional multicenter study included an exposed group of ICs from different French centers and an unexposed control group of non-medical workers. Individual information was collected about cataract risk factors and past and present workload in catheterization laboratory. All participants had a clinical eye examination to classify the lens opacities (nuclear, cortical, or posterior subcapsular) with the international standard classification LOCS III. Results The study included 106 ICs (mean age = 51 ± 7 years) and 99 unexposed control subjects (mean age = 50 ± 7 years). The groups did not differ significantly in the prevalence of either nuclear or cortical lens opacities (61% vs. 69% and 23% vs. 29%, respectively). However, posterior subcapsular lens opacities, were significantly more frequent among ICs (17% vs. 5%, p = 0.006), for an OR = 3.9 1.3–11.4. The risk increased with duration of activity but no clear relationship with workload was observed. However, the risk appeared lower for regular users of protective lead glasses (OR = 2.2 0.4–12.8). Conclusions ICs, in France as elsewhere, are at high risk of posterior subcapsular cataracts. Use of protective equipment against X-rays, in particular lead glasses, is strongly recommended to limit this risk.
The increasing number and complexity of these procedures have led to a higher number of patients at risk for tissue reactions like skin injuries. Monitoring of their dose indicators is essential in ...recognizing these patients. The aim of this work was to determine local diagnostic reference levels (DRLs) for recanalization of chronic total occlusion (CTO) and other occlusions procedures. All data from patients who underwent cardiac procedures were reviewed and classified according to their complexity. Dose indicators such as fluoroscopy time (FT), dose area product (DAP), and air kerma at patient entrance reference point (AKr ) were recorded. Correlations with patient's body mass index, operators, procedure strategy, and complexity were studied. For CTO, the mean DAP, AKr , and FT were 252 ± 234 Gycm2 , 3,985 ± 3,579 mGy, and 47 ± 36 minutes, respectively. To better reflect the non-Gaussian distribution of data, the median and the 75th percentile values were also reported: median DAP, 172 Gycm2 ; 75th percentile DAP, 350 Gycm2 ; median AKr , 2,714 mGy; and 75th percentile AKr, 5,921 mGy. A tentative new set of values were suggested to take into account the complexity difference in recanalization of total occlusions according to their antegrade or retrograde approach. These approach-specific DRLs for total occlusions were mean DAP (120 ± 114 Gycm2 ), mean AKr (1,789 ± 1,933 mGy), and mean FT (22 ± 18 minutes) for antegrade approach and mean DAP (459 ± 304 Gycm2 ), mean AKr (6,881 ± 4,243 mGy), and mean FT (82 ± 40 minutes) for retrograde approach. The other significant values were median DAP (84 Gycm2 ), 75th percentile DAP (147 Gycm2 ), median AKr (1,160 mGy), and 75th percentile AKr (2,176 mGy) for antegrade approach and median DAP (422 Gycm2 ), 75th percentile DAP (552 Gycm2 ), median AKr (6,295 mGy), and 75th percentile AKr (8,064 mGy) for retrograde approach. In conclusion, a set of local DRL values from a large center were assessed. DRLs were provided for antegrade and retrograde approaches, reflecting the difference in difficulty from these 2 kinds of CTOs. The wide dose estimator values variations were explained through procedure complexity. The values obtained for the other more classic percutaneous coronary interventions were comparable with those found in the literature.
To determine the radiation exposure associated with CT scans in a population of patients with cystic fibrosis (CF).
We reviewed the medical charts of patients with typical CF who received regular ...medical management in a reference center from birth to March 31, 2004.
Among 80 patients with a total follow-up time of 1,231 person-years, 79 patients received a total of 269 CT scans, including 249 thoracic CT scans. The full parameters of the examination were available for 185 thoracic CT scans, allowing the effective dose (ED) and organ doses to be calculated. The ED was determined by the number of slices and the type of CT scans. The ED per thoracic CT scan was asymmetrically distributed (mean ED, 6.5 mSv; range 1.5 to 29.3 mSv). The mean doses delivered to the four most strongly exposed organs (lungs, breasts, bone marrow, and thyroid gland) were 18.6, 16.9, 5.2, and 3.5 mGy, respectively. The mean lifetime number of CT scans per patient was 3.2 (range, 0 to 13 scans), and the average lifetime ED was 19.5 mSv per patient (range, 2.2 to 75.8 mSv). Age at the first CT scan fell over the years, from 20 years for patients born before 1980 to 1.9 years for patients born after 1997.
The mean ED per CT scan in CF patients is about 6.5 mSv. Age at the first CT scan is lower in the most recent generation of patients. The lifetime ED of radiation received by CF patients, especially in the most recent generation, warrants long-term follow-up.
The benefits of cardiac imaging are immense, and modern medicine requires the extensive and versatile use of a variety of cardiac imaging techniques. Cardiologists are responsible for a large part of ...the radiation exposures every person gets per year from all medical sources. Therefore, they have a particular responsibility to avoid unjustified and non-optimized use of radiation, but sometimes are imperfectly aware of the radiological dose of the examination they prescribe or practice. This position paper aims to summarize the current knowledge on radiation effective doses (and risks) related to cardiac imaging procedures. We have reviewed the literature on radiation doses, which can range from the equivalent of 1-60 milliSievert (mSv) around a reference dose average of 15 mSv (corresponding to 750 chest X-rays) for a percutaneous coronary intervention, a cardiac radiofrequency ablation, a multidetector coronary angiography, or a myocardial perfusion imaging scintigraphy. We provide a European perspective on the best way to play an active role in implementing into clinical practice the key principle of radiation protection that: 'each patient should get the right imaging exam, at the right time, with the right radiation dose'.
Background The eye is well known to be sensitive to clearly high doses (>2 Gy) of ionizing radiation. In recent years, however, cataracts have been observed in populations exposed to lower doses. ...Interventional cardiologists are repeatedly and acutely exposed to scattered ionizing radiation (X-rays) during the diagnostic and therapeutic procedures they perform. These "low" exposures may cause damage to the lens of the eye and induce early cataracts, known as radiation-induced cataracts. The O'CLOC study (Occupational Cataracts and Lens Opacities in interventional Cardiology) was designed to test the hypothesis that interventional cardiologists, compared with an unexposed reference group of non-interventional cardiologists, have an increased risk of cataracts. Method/Design The O'CLOC study is a cross-sectional study that will include a total of 300 cardiologists aged at least 40 years: one group of exposed interventional cardiologists and another of non-interventional cardiologists. The groups will be matched for age and sex. Individual information, including risk factors for cataracts (age, diabetes, myopia, etc.), will be collected during a telephone interview. A specific section of the questionnaire for the exposed group focuses on occupational history, including a description of the procedures (type, frequency, radiation protection tool) used. These data will be used to classify subjects into "exposure level" groups according to cumulative dose estimates. Eye examinations for all participants will be performed to detect cataracts, even in the early stages (lens opacities, according to LOCS III, the international standard classification). The analysis will provide an estimation of the cataract risk in interventional cardiology compared with the unexposed reference group, while taking other risk factors into account. An analysis comparing the risks according to level of exposure is also planned. Discussion This epidemiological study will provide further evidence about the potential risk of radiation-induced cataracts at low doses and contribute to cardiologists' awareness of the importance of radiation protection. Trial Registration NCT01061463
Over one million European children undergo computed tomography (CT) scans annually. Although moderate- to high-dose ionizing radiation exposure is an established risk factor for hematological ...malignancies, risks at CT examination dose levels remain uncertain. Here we followed up a multinational cohort (EPI-CT) of 948,174 individuals who underwent CT examinations before age 22 years in nine European countries. Radiation doses to the active bone marrow were estimated on the basis of body part scanned, patient characteristics, time period and inferred CT technical parameters. We found an association between cumulative dose and risk of all hematological malignancies, with an excess relative risk of 1.96 (95% confidence interval 1.10 to 3.12) per 100 mGy (790 cases). Similar estimates were obtained for lymphoid and myeloid malignancies. Results suggest that for every 10,000 children examined today (mean dose 8 mGy), 1-2 persons are expected to develop a hematological malignancy attributable to radiation exposure in the subsequent 12 years. Our results strengthen the body of evidence of increased cancer risk at low radiation doses and highlight the need for continued justification of pediatric CT examinations and optimization of doses.
•Critical analysis of available Skin Dose Calculation (SDC) software tools.•Patient radiation protection in relation to skin dose in interventional cardiology.•Review of SDC capabilities to display ...dose distribution.
In interventional cardiology, patients may be exposed to high doses to the skin resulting in skin burns following single or multiple procedures. Reviewing and analysing available software (online or offline) may help medical physicists assessing the maximum skin dose to the patient together with the dose distribution during (or after) these procedures.
Capabilities and accuracy of available software were analysed through an extensive bibliography search and contacts with both vendor and authors. Their markedly differed among developers.
In total, 22 software were identified and reviewed according to their algorithms and their capabilities. Special attention was dedicated to their main features and limitations of interest for the intended clinical use.
While the accuracy of the 12 software products validated with measurements on phantoms was acceptable (within ± 25%), the agreement was poor for the two products validated on patients (within ± 43% and ± 76%, respectively). In addition, no software has been validated on angiographic units from all manufacturers, though several software developers claimed vendor-independent transportability. Only one software allows for multiple procedures dose calculation.
Large differences among vendors made it clear that work remains to be done before an accurate and reliable skin dose mapping is available for all patients.
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.
Radiation dose to the eye lens is a crucial issue for interventional cardiologists (ICs) who are exposed during the procedures they perform. This paper presents a retrospective assessment of the ...cumulative eye lens doses of ICs enrolled in the O'CLOC study for Occupational Cataracts and Lens Opacities in interventional Cardiology. Information on the workload in the catheterisation laboratory, radiation protection equipment, eye lens dose per procedure and dose reduction factors associated with eye-protective equipment were considered. For the 129 ICs at an average age of 51 who had worked for an average period of 22 years, the estimated cumulative eye lens dose ranged from 25 mSv to more than 1600 mSv; the mean ± SD was 423 ± 359 mSv. After several years of practice, without eye protection, ICs may exceed the new ICRP lifetime eye dose threshold of 500 mSv and be at high risk of developing early radiation-induced cataracts. Radiation protection equipment can reduce these doses and should be used routinely.
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