Exposure to low-dose ionizing radiation from medical imaging procedures.

PurposeAdolescent idiopoathic scoliosis (AIS) is a progressive spinal deformity, most often observed in female patients of pubescent age. The deformity’s severity, its progression through time, its treatment and subsequent follow-up are assessed with routine radiological evaluation of the patient’s full spine. This study aimed to determine the cumulative radiation exposure in average patients with AIS treated by brace or surgery throughout their treatment.MethodsThe average number of imaging procedures and corresponding radiation doses were retrospectively obtained from the medical charts of AIS patients treated conservatively and/or surgically at our institution. The median radiation exposure of all imaging modalities was stated in effective dose (mSv). The estimated cumulative effective radiation dose of the each treatment group was determined by multiplication of the average number of imaging conducted, and the median effective radiation dose per imaging modality.ResultsIn total, 73 AIS patients were included (28 brace, 45 surgically). Patients treated with a brace were subjected to an average of 9.03 full spine radiographs, resulting in an estimated effective cumulative dose of 0.505 mSv over a median treatment period of 3.23 years. Patients treated surgically received an average of 14.29 full spine radiographs over a median treatment period of 2.76 years. The estimated effective cumulative dose amounted from 0.951 to 1.841 mSv, depending on the surgical technique.ConclusionThe cumulative effective radiation doses rendered to AIS patients as part of their treatment and follow-up were relatively low. However, every exposure to ionising radiation for medical imaging purposes should be minimised.

This study was undertaken to quantify the cumulative effective dose (CED) of radiation and the dose to relevant organs in endovascular aortic repair (EVAR) patients, to assess radiation risks and to evaluate the clinical usefulness of multi-detector computed tomography (MDCT) follow-up. The radiation exposures were obtained from 71 consecutive EVAR patients with a follow-up duration ≥1year. Dose calculations were performed on an individual basis and expressed as effective doses and organ doses. Radiation risk was expressed as risk of exposure-induced death (%), using the biological effects of ionising radiation model. Two radiologists independently assessed the images for abdominal aortic aneurysm expansion without endoleaks, thrombotic occlusion, endoleaks and device migration. They first reviewed arterial imaging alone and subsequently added non-contrast and delayed phases to determine the overall performance. The median total CED and annual CED were 224 and 104mSv per patient-year. The median cumulative organ doses were 191, 205, 230, 269 and 271mSv for lung, bone marrow, liver, colon and stomach, respectively. The average risk of exposure-induced death was 0.8% (i.e., odds 1 in 130). All the findings related to EVAR outcome and leading to a change in patient management were visible during the arterial phase of the MDCT angiography. Omission of the unenhanced scan and the venous phase of the MDCT angiography would have led to a significant reduction of about 60% of the associated MDCT radiation exposure in a single patient. EVAR patients received high radiation doses and the excess cancer risk attributable to radiation exposure is not negligible. The unenhanced scan and the venous phase of the MDCT angiography could have been omitted without compromising the utility of the examination and with a significant reduction of doses and associated risks.

Purpose: Diagnostic imaging is used frequently in patients with Crohn's disease (CD); therefore, CD patients may be exposed to high amounts of radiation from diagnostic imaging in their lifetime. Frequent exposure to radiation increases the incidence of malignancy. The aim of this study was to identify demographic and disease-specific characteristics that are associated with higher diagnostic radiation exposure in patients with CD. Methods: 106 patients with CD who were initiated on anti-TNF or immunomodulator therapy with at least one year of follow-up between 2004 and 2008 were included. All radiologic studies done 1 year before and 1 year after initiation of immunomodulators or anti-TNF therapy were recorded. The cumulative effective dose of radiation over the 2 years was calculated using standardized effective doses. Demographics, disease phenotype, disease duration, and presence of extraintestinal manifestations of disease (EIM) were extracted from a preexisting clinical database. The cohort was divided into quartiles by effective dose of radiation. Logistic regression analysis was performed to identify associations between demographic and disease-specific variables and cumulative effective dose of diagnostic radiation ≥55 mSv (top quartile effective dose of radiation). Results: 86% of the patients were <40 years old at diagnosis. 68% were female. 79% were Caucasian. 32%, 54%, and 14% had ileal, ileocolonic, and colonic disease, respectively. 27%, 34%, and 39% had inflammatory, stricturing, and penetrating disease, respectively. 29% had perianal disease and 29% had EIM. 64% were treated with anti-TNF agents and 38% with immunomodulators. 55% of patients were diagnosed with CD for less than 10 years prior to the study. Exposure to diagnostic radiation did not differ by age, sex, race, age at diagnosis or duration of disease, smoking status, presence of upper tract or perianal disease, presence of EIM or type of medical therapy initiated. Obstructing or penetrating disease was associated with higher exposure to diagnostic radiation (OR 4.84, 95% CI 1.07 to 21.98). There was also a trend to higher radiation exposure in patients with ileal or ileocolonic compared to patients with colonic disease (OR 5.2, 95% CI 0.59 to 45.87). Conclusion: Obstructing and penetrating CD is associated with higher diagnostic radiation exposure compared to patients with inflammatory disease behavior. Ileal and ileocolonic disease location compared to colonic disease location is also likely associated with higher radiation exposure. The use of ionizing radiation in the diagnostic evaluation of CD, especially in patients with complicated disease behavior and small bowel disease, should be minimized in an effort to reduce their lifetime exposure to radiation.

Children with malignant lymphoma undergo many diagnostic procedures that involveexposure to ionising radiation. In addition, many, but by no means all, undergo furtherexposure to ionising radiation during radiotherapy. While therapeutic radiation exposuresare prescribed, the extent of radiation exposure arising from diagnostic procedures utilisedin such children is largely unknown. We completed an audit of the radiation doses arisingfrom diagnostic imaging procedures performed in a cohort of children with malignantlymphoma.The cumulative effective radiation dose associated with radiographic and radioisotopicprocedures was derived for 81 children and adolescents with malignant lymphoma duringtheir diagnosis, treatment and follow-up. Thirty-eight of the 42 patients (90%) withHodgkin lymphoma were alive at study termination, with follow-up periods ranging from1.9 to 11.7 years (median 5.3). Thirty-three of the 39 patients (85%) with non-Hodgkinlymphoma were alive at study termination with follow-up periods ranging from 2.4 to 12.3years (median 7.5). The median effective dose was 518 mSv for patients with Hodgkinlymphoma and 309 mSv for those with non-Hodgkin lymphoma. The maximumeffective dose was 1.7 Sv. The principal contributors to the effective dose werecomputed tomography (CT) and nuclear medicine imaging procedures using 67Ga. Protocols for the management of children and adolescents with malignant lymphomashould be reviewed in order to reduce the radiation detriment without loss of essentialdiagnostic information.

IntroductionPatients with Crohn’s Disease [CD] are often exposed to ionising radiation for the diagnosis and evaluation of disease with inherent risks from protracted exposure. Meanwhile, bolder definitions of disease control...

Background Children with congenital heart disease are exposed to ionising radiation early in their lives when tissue sensitivity for radiation is highest. This might provoke DNA fractures and cancer development. Our first study with an observation period from 1980–1998 showed a 4.4-fold increased cancer risk for children who had at least one cardiac catheterization in the first year of life. Objectives This study aimed to reassess the risk of cancer for children who underwent at least one cardiac catheterization between 1999 and 2013 with a follow-up of seven years. Methods This retrospective, single-center study included 2765 children who underwent at least one cardiac catheterization before eight years of age between January 1999 and December 2013. 1688 received their first cardiac catheterization in the first year of life, 1074 between first and eighth year of life. Catheterization and patient data were obtained from our database, and cancer diagnoses up to age 15 were matched with German Childhood Cancer Registry. For each tumor patient and for each of the 60 randomly selected control patients cumulative effective radiation doses were calculated. Results 37667.16 person-years were evaluated. A total of ten patients developed a malignant tumor, while 5.82 were expected (SIR 1.72; CI 0.82–3.16; p=0.0722). Eight of these ten tumors developed in patients who received their first cardiac catheterization in the first year of life, while 3.99 were expected (SIR 2.0; CI 0.71–3.62; p=0.1095). The cancer group performed an average of 3.7 cardiac catheterizations per patient, with a mean cumulative effective dose of 24,79mSv. In the control group consisting of 60 patients, 2.1 cardiac catheterizations were performed per patient with an average cumulative effective dose of 21.04mSv. Three of the ten tumor patients have chromosomal abnormalities. The cancers observed are two leukemia, two lymphoma, two CNS tumors, one osteosarcoma, two nephroblastoma and one hepatoblastoma. Conclusion There is still an increased risk of cancer development for children with congenital heart disease exposed to ionizing radiation early in life. However, due to technical development and increased sensitivity to this fact, we observed a decrease in cancer disease compared to our previous study with catherization between 1980 and 1998. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Stiftung Kinderherz

ObjectiveTo evaluate the appropriateness of imaging tests associated with radiation in the field of otolaryngology according to the available recommendations, and to estimate the effective radiation dose associated.MethodCross-sectional epidemiological study of the totality of the imaging test requests carried out by two Spanish hospitals (n = 1931). We collected the following information: patient demographic data, type of imaging test, imaging tests referred in the previous 12 months, referrer department and diagnostic suspicion. In accordance with the available guidelines, we considered the requests: (a) Appropriate; (b) Inappropriate; (c) Not adequately justified; (d) Not included in the guidelines. We calculated the prevalence of each category and their variation according to the different variables. Collective and per capita effective dose were calculated for each category.ResultsOf the 538 requests, 42% were considered appropriate, 34.4% inappropriate, 11.9% not adequately justified and 11.7% not included in the guidelines. Imaging tests requested by general partitioners (aOR: 0.18; 95% CI: 0.06–0.50) and clinical departments (aOR: 0.27; 95% CI: 0.11–0.60) were less likely to be considered appropriate than those requested by the Otolaryngology department. Patients with a diagnosis suspicion of tumour pathology were more likely to have a requested imaging test classified as appropriate (aOR: 7.12; 95% CI: 3.25–15.61). The cumulative effective dose was 877.8 mSv, of which 40% corresponded to tests classified as inappropriate.ConclusionsA high percentage of imaging tests are considered as inappropriate in the field of otolaryngology, with a relevant frequency of associated effective radiation dose. Type of department, the diagnostic suspicion and the type of imaging tests were variables associated to the inappropriateness of the test.

Impact of Obesity on Overall Radiation Exposure for Patients Who Underwent Radiofrequency Ablation of Atrial Fibrillation

Background/AimsRecently, several studies have revealed that diagnostic imaging can result in exposure to harmful levels of ionizing radiation in inflammatory bowel disease patients. However, the extent of radiation exposure in intestinal Behcet disease (BD) patients has not been documented. The aim of this study was to estimate the radiation exposure from abdominal imaging studies in intestinal BD patients.MethodsPatients with a diagnosis of intestinal BD established between January 1990 and March 2012 were investigated at a single tertiary academic medical center. The cumulative effective dose (CED) was calculated retrospectively from standard tables and by counting the number of abdominal imaging studies performed. High exposure was defined as CED >50 mSv.ResultsIn total, 270 patients were included in the study. The mean CED was 41.3 mSv, and 28.1% of patients were exposed to high levels of radiation. Computed tomography (CT) accounted for 81.7% of the total effective dose. In multivariate analyses, predictors of high radiation exposure were azathioprine/6-mercaptopurine use, surgery, and hospitalization.ConclusionsApproximately a quarter of intestinal BD patients were exposed to harmful levels of diagnostic radiation, mainly from CT examination. Clinicians should reduce the number of unnecessary CT examinations and consider low-dose CT profiles or alternative modalities such as magnetic resonance enterography.

Computed tomography (CT) plays a pivotal role in the diagnosis, severity assessment and recognition of complications in patients with acute pancreatitis (AP). Exposure to cumulative radiation dose increases the risk of malignancy. This study aims to retrospectively investigate imaging utilisation patterns in AP and quantify cumulative effective dose (CED), and identify predictors of high radiation exposure. Adults admitted with AP between 2012 and 2013 were retrospectively reviewed. All imaging over the subsequent 10 years was analysed, and CED was calculated from dose reports or estimated using diagnostic reference levels where required. High exposure was defined as CED > 100 mSv, a dose associated with an increased lifetime risk of malignancy. One hundred-thirteen patients were included with 3022 imaging studies (92 acute interstitial oedematous pancreatitis (AIOP), 21 necrotising pancreatitis (NP)), CT comprised approximately 18% of examinations but delivered > 85% of radiation. Median (IQR) CED was 19.5 mSv for AIOP and 43.3 mSv for NP (p = 0.004). CED exceeded 100 mSv in 4.3% (4/92) of AIOP and 19% (4/21) of NP patients. Overall, 7% (8/113) of the cohort exceeded a CED of 100 mSv. No significant associations were found between CED and aetiology, pseudocyst formation, or mortality. Over a decade of follow-up, 7% of patients with acute pancreatitis exceeded the 100 mSv threshold, with CT accounting for the vast majority of exposure. Necrotising pancreatitis was associated with significantly higher cumulative doses than interstitial disease. Given that up to 30% of patients develop recurrent pancreatitis, strategies to minimize radiation exposure are essential. Optimisation of CT protocols and wider use of non-ionising modalities, including magnetic resonance imaging (MRI) and endoscopic ultrasound where appropriate, may help balance diagnostic accuracy with radiation stewardship.

Evaluation of cumulative effective dose and cancer risk from repetitive full spine imaging using EOS system: Impact to adolescent patients of different populations

Spycher et al. conducted a nationwide census-based cohort study to investigate whether the incidence of childhood cancer is associated with external exposure to natural background radiation from terrestrial gamma and cosmic rays. The authors claim their results suggest an increased risk of cancer among children exposed to external dose rates of background ionizing radiation of ≥ 200 nSv/h (1.8 mSv/yr) when compared with those exposed to < 100 nSv/h (0.9 mSv/yr). Furthermore, they claim the hazard ratios for each mSv increase in cumulative dose of external radiation are 1.028 (95% confidence interval [CI]: 1.008, 1.048) for any cancer, 1.036 (95% CI: 0.997, 1.077) for leukemia, 1.007 (95% CI: 0.964, 1.052) for lymphoma, and 1.042 (95% CI: 1.008, 1.084) for central nervous system tumors. Regarding the claimed increasing hazard ratios for childhood cancer for each mSv increase in cumulative dose of external radiation, this would be expected to be the case irrespective of the cause of childhood cancer. This is because childhood cancer cumulative incidence increases with follow-up time, which is positively correlated with cumulative radiation dose from birth. Had cumulative exposure to air pollution, cumulative food intake, or cumulative water intake been used as the risk factor, a similar outcome would be expected because all are positively correlated with follow-up time. The authors used in their analyses the doubly weighted (via radiation and tissue weighting factors) hypothetical effective dose rate and effective dose related to total-body irradiation from sources outside the body. They were apparently unaware that tissue weighting factors used are based on detriment rather than solely on cancer and that all significant contributions to radiation absorbed dose need to be accounted for. The authors omitted the very important contributions to radiation dose from radionuclides inside the body and from medical procedures. For example, the internal radiation dose to active bone marrow from radon and thoron can be significant (Richardson et al. 1991). Thus, misclassification of individuals to effective dose and dose rate groups likely occurred more frequently than acknowledged by Spycher et al. In addition, when focusing on a specific type of potential outcome (e.g., leukemia) and its association with radiation exposure of a specific target tissue (e.g., active bone marrow), it is better to use the equivalent dose, which involves only the radiation weighting factor, when a mixture of different radiations are involved (National Research Council 2006). This guards against unnecessary systematic error associated with using both the subjective radiation and tissue weighting factors to get the effective dose that was used by the authors. The individual-specific radiation doses and dose rates assigned by Spycher et al. likely involved significant errors (statistical and systematic), with the dose error possibly being larger than the effective dose assigned to the individual. Part of the systematic error relates to neglected doses from other sources (e.g., internal radionuclides). Because the focus of the research was on very small radiation dose rates and small cumulative doses, it is important to address dose and dose rate errors when conducting such analyses. It is also important to address uncertainty associated with other confounding factors studied (traffic-related air pollution, electromagnetic fields from radio and TV transmitters and from high-voltage power lines, degree of urbanization of municipality, socioeconomic status, etc.) as well as errors related to the use of probabilistic record linkage between the Swiss Childhood Cancer Registry and the Swiss National Cohort. If such errors and uncertainty had been addressed in the authors’ logistic regression analyses, then it is likely that no association between background radiation and childhood leukemia would have been suggested by the research results obtained.

Medical imaging plays a major role in coronavirus disease-2019 (COVID-19) patient diagnosis and management. However, the radiation dose received from medical procedures by these patients has been poorly investigated. We aimed to estimate the cumulative effective dose (CED) related to medical exposure in COVID-19 patients admitted to the intensive care unit (ICU) in comparison to the usual critically ill patients. We designed a descriptive cohort study including 90 successive ICU COVID-19 patients admitted between March and May 2020 and 90 successive non-COVID-19 patients admitted between March and May 2019. In this study, the CED resulting from all radiological examinations was calculated and clinical characteristics predictive of higher exposure risk identified. The number of radiological examinations was 12.0 (5.0-26.0) [median (interquartile range) in COVID-19 vs. 4.0 (2.0-8.0) in non-COVID-19 patient (P < 0.001)]. The CED during a four-month period was 4.2 mSv (1.9-11.2) in the COVID-19 vs. 1.2 mSv (0.13-6.19) in the non-COVID-19 patients (P < 0.001). In the survivors, the CED in COVID-19 vs. non-COVID-19 patients was ≥100 mSv in 3% vs. 0%, 10-100 mSv in 23% vs. 15%, 1-10 mSv in 56% vs. 30% and <1 mSv in 18% vs. 55%. The CED (P < 0.001) and CED per ICU hospitalization day (P = 0.004) were significantly higher in COVID-19 than non-COVID-19 patients. The CED correlated significantly with the hospitalization duration (r = 0.45, P < 0.001) and the number of conventional radiological examinations (r = 0.8, P < 0.001). To conclude, more radiological examinations were performed in critically ill COVID-19 patients than non-COVID-19 patients resulting in higher CED. In COVID-19 patients, contribution of strategies to limit CED should be investigated in the future.

The growing use of imaging procedures, such as computed tomography (CT), that employ low-dose ionizing radiation has stoked concerns about risks for radiation-related cancer. A single, 10-millisievert (mSv) dose (approximately the exposure from a whole-body CT scan) produces an estimated lifetime risk for developing a solid cancer or leukemia of 1 in 1000, according to a recent National Research Council report. In addition, radiation exposure from CT scanning accounts for an estimated …

Computed tomography (CT) imaging contributes to a major part of medical radiation exposure. With regard to patients safety, frequent CT examinations (CTEs) performed on the same patient are of particular concern. Tools for tracking the individual patient radiation exposure history and cumulative dose assessment may become important. Here, the applicability of the NRPB-SR250 software was assessed in a retrospective analysis of radiation doses from CTE made consecutively in male patients. Most of the examinations focused on the abdomen or the whole body. The mean number of CTs per patient was 6.8. Significant cumulative effective doses were observed: 76 (66 %) patients received an effective dose higher than 50 mSv, while the maximum was ∼280 mSv. A more than 3-fold effective dose difference was observed between scanners, depending on the scanning protocols. The NRPB-SR250 software proved to be a robust tool for the assessment of organ doses and the effective radiation dose from CT, while challenges were encountered in finding the precise imaging data in retrospective protocols.