Median Cumulative Effective Dose Research Articles

Radiation Exposure among Patients with Inflammatory Bowel Disease: A Single-Medical-Center Retrospective Analysis in Taiwan.

Inflammatory bowel disease (IBD) is a chronic and relapsing disease that can be complicated by abscesses, fistulas, or strictures of the damaged bowel. Endoscopy or imaging studies are required to diagnose and monitor the treatment response or complications of the disease. Due to the low incidence of the disease in Taiwan, the pattern of radiation exposure from medical imaging has not been well studied previously. This retrospective study aimed to evaluate the pattern of radiation exposure in 134 Taiwanese IBD patients (45 CD and 89 UC) diagnosed and followed at Changhua Christian Hospital from January 2010 to December 2020. We reviewed the patient demographic data and radiation-containing image studies performed during the follow-up. The cumulative effective dose (CED) was calculated for each patient. During a median follow-up of 4 years, the median CED was higher for patients with CD (median CED 21.2, IQR 12.1–32.8) compared to patients with UC (median CED 2.1, IQR 0–5.6) (p < 0.001). In addition, the CD patients had a trend of a higher rate of cumulative ≥50 mSv compared with the UC patients (6.7% vs. 1.1%, p = 0.110). In conclusion, our study found a higher radiation exposure among CD patients compared to patients with UC, representing the complicated nature of the disease. Therefore, increasing the use of radiation-free medical imaging such as intestinal ultrasound or magnetic resonance imaging should be advocated in daily practice to decrease the risk of excessive radiation exposure in these patients.

Characteristics of Cumulative Annual Radiation Exposure in Young Intensive Care Unit Survivors.

Patients admitted to the intensive care unit (ICU) are at high risk for hazardous medical radiation exposure. However, the cumulative annual radiation exposure in ICU survivors remains unknown. This was a single-center retrospective study of all critically ill adult patients admitted to the 64-bed adult medical ICU at a quaternary medical center. The study included patients aged 18 to 39 years admitted through the year 2013 (January 1, 2013-December 31, 2013) who survived their respective ICU admission. A total of 353 patients were included in the study. The median cumulative effective dose (CED) for the calendar year was 9.14 mSv (interquartile range, 1.74-27 mSv). In 11.6% of the patients (n = 41), CED was more than 50 mSv, while 5.1% of the patients (n = 18) exceeded annual CED of 100 mSv. Overall, radiation exposure from ICU-related imaging studies was lower than those from other medical settings (mean difference, -9.2 ± 83.6; P &lt; 0.05). However, there was no statistically significant difference in exposure (ICU versus non-ICU) when restricting the analysis to patients with a CED of greater than 50 and greater than 100 mSv. Eighty-seven percent of the original cohort was alive at the end of the year. Young ICU survivors are at risk for high annual radiation exposure from both ICU and non-ICU sources. A subset is exposed to hazardous annual radiation exposure in excess of 100 mSv.

Burden of Ionizing Radiation in the Diagnosis and Management of Necrotizing Pancreatitis.

INTRODUCTION:A step-up endoscopic or percutaneous approach improves outcomes in necrotizing pancreatitis (NP). However, these require multiple radiographic studies and fluoroscopic procedures, which use low-dose ionizing radiation. The cumulative radiation exposure for treatment of NP has not been well defined.METHODS:We conducted a retrospective study of consecutive patients with NP admitted to University of California San Francisco Medical Center from January 2011 to June 2019. We calculated effective doses for fluoroscopic procedures using the dose area product and used the National Cancer Institute tool for computed tomography studies. The primary outcome was the cumulative effective dose (CED). Multivariable logistic regression was used to evaluate risk factors of high exposure (CED > 500 mSv).RESULTS:One hundred seventy-one patients with NP (mean follow-up 40 ± 18 months) underwent a median of 7 (interquartile range [IQR] 5–11) computed tomography scans and 7 (IQR 5–12) fluoroscopic procedures. The median CED was 274 mSv (IQR 177–245) and 30% (51) of patients received high exposure. Risk factors of high exposure include multiorgan failure (aOR 3.47, 95%-CI: 1.53–9.88, P = 0.003), infected necrosis (adjusted odds ratio [aOR] 3.89 95%-CI:1.53–9.88, P = 0.005), and step-up endoscopic approach (aOR 1.86, 95%-CI: 1.41–1.84, P = 0.001) when compared with step-up percutaneous approach.DISCUSSION:Patients with NP were exposed to a substantial amount of ionizing radiation (257 mSv) as a part of their treatment, and 30% received more than 500 mSv, which corresponds with a 5% increase in lifetime cancer risk. Severity of NP and a step-up endoscopic approach were associated with CED > 500 mSv. Further studies are needed to help develop low-radiation treatment protocols for NP, particularly in patients receiving endoscopic therapy.

Cumulative radiation dose incurred during the management of complex pleural space infection

BackgroundComplex pleural space infections are commonly managed with antibiotics, pleural drainage, intrapleural fibrinolytic therapy, and surgery. These strategies often utilize radiographic imaging during management, however little data is available on cumulative radiation exposure received during inpatient management. We aimed to identify the type and quantity of radiographic studies along with the resultant radiation exposure during the management of complex pleural space infections.MethodsRetrospective review of community network healthcare system from January 2015 to July 2018. Patients were identified through billing databases as receiving intrapleural fibrinolytic therapy and/or surgical intervention. Patient demographics, clinical outcomes, and inpatient radiographic imaging was collected to calculate cumulative effective dose.ResultsA total of 566 patients were identified with 7275 total radiographic studies performed and a median cumulative effective dose of 16.9 (IQR 9.9–26.3) mSv. Multivariable linear regression analysis revealed computed tomography use was associated with increased cumulative dose, whereas increased age was associated with lower cumulative dose. Over 74% of patients received more than 10 mSv, with 7.4% receiving more than 40 mSv.ConclusionsThe number of radiographic studies and overall cumulative effective dose in patients hospitalized for complex pleural space infection was high with the median cumulative effective dose > 5 times normal yearly exposure. Ionizing radiation and modern radiology techniques have revolutionized medical care, but are likely not without risk. Additional study is warranted to identify the frequency and imaging type needed during complex pleural space infection management, attempting to keep ionizing radiation exposure as low as reasonably possible.

A retrospective audit of cumulative ionising radiation levels in hospitalised pregnant patients.

Among hospitalised patients, diagnostic radiation is possibly used least on pregnant patients due to the fear of ionising radiation on the fetus; however, what levels are currently being prescribed. To assess the cumulative levels of ionising radiation received by pregnant patients during a single admission to a tertiary hospital. A retrospective audit of pregnant patients admitted to Flinders Medical Centre, South Australia, Australia, between 2013 and 2017 inclusive was performed. All procedures utilising ionising radiation were collected including conventional radiology, computed tomography, fluoroscopy and nuclear medicine. Individual and cumulative effective doses for mother and fetus were calculated using patient dose reports and published conversion factors. From 547 patients, the median cumulative effective dose was 0.02 mSv and only five patients received more than 10 mSv, with 19.07 mSv the highest dose received. The median fetal cumulative effective dose was 0.01 mSv but only three fetuses received more than 10 mSv, likely due to fetal exclusion in some procedural fields of view. Stays longer than tendays were associated with significantly higher cumulative effective dose, as did those with maternal cardiovascular related admission, for both maternal and fetal exposures. These results suggest that pregnant patients are exposed to low doses of ionising radiation, in both individual procedures and cumulative doses. The detrimental risks associated with these levels of ionising radiation are not overt and so clinicians should question which risk is higher, the ionising radiation from the radiological procedures received or the lack of diagnostic information if avoided?

Cohort study of occupational cosmic radiation dose and cancer mortality in German aircrew, 1960–2014

ObjectivesTo determine cancer mortality compared with the general population and to examine dose-response relationships between cumulative occupational radiation dose and specific cancer outcomes in the German aircrew cohort.MethodsFor a cohort...

Patients undergoing recurrent CT scans: assessing the magnitude.

To assess percent of patients undergoing multiple CT exams that leads to cumulative effective dose (CED) of ≥ 100 mSv and determine their age distribution. Data was retrieved retrospectively from established radiation dose monitoring systems by setting the threshold value of 100 mSv at four institutions covering 324 hospitals. The number of patients with CED ≥ 100 mSv only from recurrent CT exams during a feasible time period between 1 and 5 years was identified. Age and gender distribution of these patients were assessed to identify the magnitude of patients in the relatively lower age group of ≤ 50 years. Of the 2.5 million (2,504,585) patients who underwent 4.8 million (4,819,661) CT exams during the period of between 1 and 5 years, a total of 33,407 (1.33%) patients received a CED of ≥ 100 mSv with an overall median CED of 130.3 mSv and maximum of 1185 mSv. Although the vast majority (72-86%) of patients are > 50 years of age, nearly 20% (13.4 to 28%) are ≤ 50 years. The minimum time to accrue 100 mSv was a single day at all four institutions, an unreported finding to date. We are in an unprecedented era, where patients undergoing multiple CT exams and receiving CED ≥ 100 mSv are not uncommon. While underscoring the need for imaging appropriateness, the consideration of the number and percent of patients with high exposures and related clinical necessities creates an urgent need for the industry to develop CT scanners and protocols with sub-mSv radiation dose, a goal that has been lingering. • We are in an era where patients undergoing multiple CT exams during a short span of 1 to 5 years are not uncommon and a sizable fraction among them are below 50 years of age. • This leads to cumulative radiation dose to individual patients at which radiation effects are of real concern. • There is an urgent need for the industry to develop CT scanners with sub-mSv radiation dose, a goal that has been lingering.

RADIATION DOSE TRENDS AND CANCER RISK ACCRUED FROM RADIATION EXPOSURE IN THE MEDICAL ICU: A 5-YEAR PERSPECTIVE

SESSION TITLE: Tuesday Electronic Posters 2 SESSION TYPE: Original Inv Poster Discussion PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM PURPOSE: Patients admitted to Medical Intensive care unit (MICU) are subjected to multiple radiological studies.Some endure radiation dose exposure [Cumulative Effective dose (CED) ] in excess of annual federal occupational health standard limits (CED≥50 mSv) and those statistically linked with cancer induction (CED≥100 mSv). We evaluated the cancer risk( life time attributable risk) from the CED accrued during a single admission and radiation dose trends over a 5 year period METHODS: This is a retrospective observational study conducted in an academic medical center involving all adult admissions (N=21,108) admitted to the MICU between January 2013 and December 2017. Clinical and radiologic data were obtained from the electronic medical records and the picture archiving & communication system. Radiation doses from ionizing radiological studies were calculated from reference values to determine CED. RESULTS: Four percent of the patients (n=562) accrued CED ≥50%, 1 % (n=195) accrued CED ≥100 mSv. The median CED was 0.72 mSv (IQR, 0.02-4.08 mSv)over a five year period with a range of 0.00 mSv to 1607 mSv . The mean MICU length of stay(LOS ) was 4.7(+/-6.7 )days and APACHE score was 65.8(+/-29.6) over a 5 year period . Higher APACHE 3 scores (p< 0.001), hepatic failure (p=0.03 ), and gastrointestinal disorders (0.0001) predicted higher CED in a multivariable linear regression model. Odds ratio of accruing CED≥ 50mSv was noted at 8.9 (CI 6.84-11.59, P< 0.0001) in gastrointestinal bleeding, 2.6 (CI 2.17-4.04, p < 0.0001) in gastrointestinal disorders ,3.58 (CI 2.69-4.78 P<0.001) in hematological disorders and 1.38 (CI 0.99-1.92 p<0.001) in Cirrhosis. CT scan and interventional radiology accounted for 59% and 29% of the total CED, respectively. The median increase in cancer risk from CED accrued was 0.36(IQR, 0.23-0.58).The Median CED remained constant across 5 years without an uptrend. CONCLUSIONS: MICU patients are exposed to radiation doses that can be substantial, exceeding federal annual occupational limits and in a select subset, exceeds >100 mSv resulting in an increased cancer risk from baseline among ICU survivors. Median CED remained constant across the study period without an uptrend. Efforts to justify, restrict & optimize the use of radiological resources when feasible, are warranted. CLINICAL IMPLICATIONS: Younger MICU survivors could be at substantial cancer risk from CED accrued in the MICU within a relatively short span of time. Those discharged could be subjected to even more medical radiation as a part of ongoing medical care, adding to the annual CED and increasing the radiogenic risk further. Attempts to mitigate radiation burden by optimizing the utilization of fluoroscopically guided interventional procedures and computerized tomography merits further discussion and research. DISCLOSURES: No relevant relationships by Sinan Abdul-Wahab, source=Web Response No relevant relationships by Anirban Bhattacharyya, source=Web Response No relevant relationships by Abhijit Duggal, source=Web Response No relevant relationships by Sravanthi Ennala, source=Web Response No relevant relationships by Nagamani Guduguntla, source=Web Response no disclosure on file for Jorge Guzman; No relevant relationships by Xiaozhen Han, source=Web Response No relevant relationships by Tarik Hanane, source=Web Response no disclosure on file for Ali Khwaja; No relevant relationships by Sudhir Krishnan, source=Web Response Advisory Committee Member relationship with Boston Scientific Corp. Please note: $1001 - $5000 Added 03/14/2019 by CHARLES MARTIN, source=Web Response, value=Consulting fee Consultant relationship with Terumo Interventional Corp. Please note: $1001 - $5000 Added 03/14/2019 by CHARLES MARTIN, source=Web Response, value=Consulting fee Advisory Committee Member relationship with BTG Inc. Please note: $1001 - $5000 Added 03/14/2019 by CHARLES MARTIN, source=Web Response, value=Consulting fee No relevant relationships by Xiaofeng Wang, source=Web Response

Patient Safety Analysis in Radiation Burden of Head Computed Tomography Imaging in 1185 Neurosurgical Inpatients

We performed a retrospective analysis in a cohort of 1185 patients at our institution who were identified as undergoing ≥1 head computed tomography (CT) examinations during their inpatient stay on the neurosurgery service, to quantify the number, type, and associated radiation burden of head CT procedures performed by the neurosurgery service. CT procedure records and radiology reports were obtained via database search and directly validated against records retrieved from manual chart review. Next, dosimetry data from the head CT procedures were extracted via automated text mining of electronic radiology reports. Among 4510 identified adult head CT procedures, 88% were standard head CT examinations. A total of 3.65 ± 3.60 head CT scans were performed during an average adult admission. The most common primary diagnoses were neoplasms, trauma, and other hemorrhage. The median cumulative effective dose per admission was 5.66 mSv (range, 1.06-84.5 mSv; mean, 8.56 ± 8.95 mSv). The median cumulative effective dose per patient was 6.4 mSv (range, 1.1-127 mSv; mean, 9.26 ± 10.0 mSv). The median cumulative radiation burden from head CT imaging in our cohort equates approximately to a single chest CT scan, well within accepted limits for safe CT imaging in adults. Refined methods are needed to characterize the safety profile of the few pediatric patients identified in our study.

Exposure to low dose computed tomography for lung cancer screening and risk of cancer: secondary analysis of trial data and risk-benefit analysis

Objective To estimate the cumulative radiation exposure and lifetime attributable risk of cancer incidence associated with lung cancer screening using annual low dose computed tomography (CT).Design Secondary analysis of data...

Correlation of Cumulative Diagnostic Radiation Exposure With Increasing Lemann Index: The Need for Increased Provider Vigilance in Certain Crohnʼs Disease Sub-groups

Introduction: Recurrent exposure to diagnostic ionizing radiation and the resultant increase in lifetime risk of cancer is a well-known concern in Crohn's disease (CD) patients. Lemann Index (LI) is a new metric that quantifies bowel damage mediated by CD. Stratification of CD patients based on change in LI over time is a novel approach to defining patient subgroups. We aimed to evaluate ionizing radiation exposure secondary to diagnostic testing, across different CD trajectories in a cohort stratified by change in LI. Methods: CD patients with 5 year(y) follow-up from a registry maintained at a tertiary center were included. LI was calculated using a computerized model from first (LI1) and last (LI2) clinical encounters. Patients were stratified based on change in index (LI2-LI1) or the delta LI (DLI) as showing improvement, no change or deterioration. Subgroups were created by dichotomizing mean improvement, mean deterioration and no change and used for association analysis with the cumulative effective dose (CED) of radiation received during 5y. Results: A total of 363 CD patients with 5y complete follow-up formed the study cohort [median age 43y (IQR: 33.3-55); 57% female; median disease duration 12y (IQR: 3-19), overall surgical exposure 69.7%]. Median (IQR) LI1, LI2 and DLI were 8 (0-54), 9 (0-75) and 0 (-22 - 47) respectively. Patients were stratified based on DLI into subgroups (A: DLI < -2.98; B: DLI -2.98 - 0; C: DLI 0, D: DLI 0 - 7.75; E: DLI >7.75). The study cohort underwent a total of 1414 diagnostic tests associated with radiation exposure (including abdominal radiographs, computed tomography [CT] scans and barium studies) with a median CED of 20mSv/person and median yearly radiation exposure of 4mSv/person/y. Use of CT scans accounted for 93.5% of CED. There was a significant difference in the number of tests and CED across the subgroups (p < 0.001), with highest and least median CED noted in groups E and C respectively [Table 1]. CED showed significant correlation with DLI (r = 0.35; p < 0.001).Table 1: Differences in cumulative effective dose of radiation received amongst Delta Lémann Index based five year trajectories of Crohn's diseaseConclusion: Identifiable subsets of patients with Crohn's disease are at risk of exposure to significant amounts of diagnostic radiation. When compared with natural background radiation exposure (3.1mSv/y), patients with rapidly worsening LI are exposed to 4 times higher dose of ionizing radiation each year. Clinicians must remain vigilant of the risk of cumulative radiation, particularly in patients with aggressive disease.

Ionizing radiation exposure as a result of diagnostic imaging in patients with lymphoma

Survival rates among patients with lymphoma continue to improve. Strategies aimed at reducing potential treatment-related toxicity are increasingly prioritized. While radiological procedures play an important role, ionizing radiation exposure has been linked to an increased risk of malignancy, particularly among individuals whose cumulative radiation exposure exceeds a specific threshold (75 millisieverts). Within this retrospective study, the cumulative radiation exposure dose was quantified for 486 consecutive patients with lymphoma. The median estimated total cumulative effective dose (CED) of ionizing radiation per subject was 69 mSv (42-118). However, younger patients (under 40 years) had a median CED of 89 mSv (55-124). This study highlights the considerable radiation exposure occurring among patients with lymphoma as a result of diagnostic imaging. To limit the risk of secondary carcinogenesis, consideration should be given to monitoring cumulative radiation exposure in individual patients as well as considering imaging modalities, which do not impart an ionizing radiation dose.

PTH-070 Patients receiving anti-tnf agents for inflammatory bowel disease: exposure to diagnostic ionising radiation and trends in imaging modalities

Introduction Concern has been raised as to the risk of malignancy in patients with inflammatory bowel disease related to their exposure to ionising radiation from diagnostic tests. A meta-analysis has reported that 8.8% of patients with inflammatory bowel disease were exposed to potentially harmful levels of diagnostic medical radiation (DMR) (defined as greater than 50 milli-sieverts (mSv)). 1 Patients requiring anti-TNF treatment for management of their disease may be at greatest risk of exposure to diagnostic medical radiation by virtue of their disease activity. AIM To determine the prevalence of exposure to a potentially harmful dose of DMR in patients receiving anti-TNF treatment and to determine predictors of high exposure. Method A retrospective review of patients receiving anti-TNF agents for IBD in a tertiary referral centre between 2005 and 2012 was undertaken. Logistic regression was used to identify predictors of exposure to a potentially harmful cumulative effective dose (CED) of >50 mSv in patients with Crohn’s disease. Variables considered as potential predictors of a harmful CED included elements of the Montreal classification of disease (site and behaviour of disease and presence of perianal disease), age and sex. Results A cohort of 149 patients was identified. The median age was 36 (range 18 to 72 years). 135 patients had Crohn’s disease. 1137 diagnostic procedures associated with exposure to ionising radiation were performed. The median CED was 10.72mSv (Range 0 to 146). 12% of all IBD patients received a potentially harmful CED of >50 mSv. In patients with Crohn’s disease, 9.6% received a CED of > 50mSv. Logistic regression failed to demonstrate a significant association between a CED of > 50mSv and the variables assessed. Abdominal CT scans accounted for 69% of the CED. During the study period the ratio of abdominal MR scans to abdominal CT scans was 1:24 and 2:3 in the first and last quartile of the study period, respectively. Conclusion 12% of IBD patients receiving anti-TNF agents for IBD in a tertiary setting received a potentially harmful dose of ionising radiation from diagnostic imaging. This was largely related to abdominal CT scans. The temporal trend towards a greater use of non-ionising radiation for diagnostic imaging in this group is therefore reassuring. Disclosure of interest None Declared. Reference Chatu et al . Aliment Pharmacol Ther. 2012;35:529

Retrospective study of cumulative diagnostic radiation exposure during childhood in patients with spina bifida

BackgroundThe Biological Effects of Ionizing Radiation Committee of the National Academy of Sciences in 2005 and other expert panels have warned that risk of cancer increases with higher doses of radiation. Children with spina bifida and hydrocephalus have far greater exposure to radiation than the average person, starting almost directly after birth and continuing throughout their lifetimes. ObjectiveThe purpose of this study was to estimate the amount of ionizing radiation that patients with spina bifida and hydrocephalus are exposed to during childhood from diagnostic imaging. MethodsThirty patients, ages 18 years or older, with spina bifida and hydrocephalus were randomly selected from a spina bifida clinic and their radiology records were reviewed. Descriptive analyses were conducted. The total radiation exposure was then calculated for the study group, and the mean effective dose per patient was determined. ResultsIn the study group, during their first 18 years, each patient had a mean of 55.1 studies and a median of 45 radiologic studies, a mean of 9.6 brain CT scans, and a mean cumulative effective dose of 81.9 mSv (2.6 mSv/patient/year over 18 years) and a median cumulative effective dose of 77.2 mSV of accumulated radiation exposure (4.5 mSv/patient/year over 18 years). ConclusionsClinicians should recognize that increased radiation exposure puts patients with spina bifida and hydrocephalus at higher risk for cancer. The population of children and adults with spina bifida and hydrocephalus should be surveyed for incidence of cancer.

Radiation exposure from diagnostic imaging in young patients with testicular cancer.

Risks associated with high cumulative effective dose (CED) from radiation are greater when imaging is performed on younger patients. Testicular cancer affects young patients and has a good prognosis. Regular imaging is standard for follow-up. This study quantifies CED from diagnostic imaging in these patients. Radiological imaging of patients aged 18-39 years, diagnosed with testicular cancer between 2001 and 2011 in two tertiary care centres was examined. Age at diagnosis, cancer type, dose-length product (DLP), imaging type, and frequency were recorded. CED was calculated from DLP using conversion factors. Statistical analysis was performed with SPSS. In total, 120 patients with a mean age of 30.7 ± 5.2 years at diagnosis had 1,410 radiological investigations. Median (IQR) surveillance was 4.37 years (2.0-5.5). Median (IQR) CED was 125.1 mSv (81.3-177.5). Computed tomography accounted for 65.3 % of imaging studies and 98.3 % of CED. We found that 77.5 % (93/120) of patients received high CED (>75 mSv). Surveillance time was associated with high CED (OR 2.1, CI 1.5-2.8). Survivors of testicular cancer frequently receive high CED from diagnostic imaging, mainly CT. Dose management software for accurate real-time monitoring of CED and low-dose CT protocols with maintained image quality should be used by specialist centres for surveillance imaging. • CT accounted for 98.3 % of CED in patients with testicular cancer. • Median CED in patients with testicular cancer was 125.1 mSv • High CED (>75 mSv) was observed in 77.5 % (93/120) of patients. • Dose tracking and development of low-dose CT protocols are recommended.

Cumulative radiation dose due to diagnostic investigations in seriously injured trauma patients admitted to critical care.

A retrospective review of case notes and radiology records was performed in order to estimate the amount and sources of ionising radiation multiply injured trauma patients are exposed to, during their initial investigations and subsequent critical care admission. Data were available for 431 radiological investigations from 36 patients. Results showed initial emergency department imaging (combined computed tomography (CT) and plain radiographs) contributed 70% of the total radiation dose. Overall, CT scans were responsible for 80% and plain radiographs 15% of the total radiation dose. Plain radiographs performed after the initial resuscitation period contributed the greatest number of investigations but accounted for only 8% of total radiation exposure. Median cumulative effective dose was estimated to be between 16 and 29 millisieverts, resulting in an estimated increased life time risk of carcinogenesis of between 1 in 614 and 1 in 1075 above baseline.

Cumulative medical radiation exposure throughout staged palliation of single ventricle congenital heart disease.

Patients with single ventricle heart disease undergoing staged palliation are exposed to ionizing radiation from multiple medical sources. We sought to quantify typical radiation burden in this population and identify risk factors for increased exposure. A retrospective review was performed of single ventricle patients surgically palliated at our institution, in which all studies utilizing ionizing radiation occurring from birth through Fontan completion were compiled. Thirty-eight patients were followed for a median of 33 months. A median of 59 radiation events occurred during follow-up, with a median cumulative effective dose of 25.7 milliSieverts (mSv). On average, cardiac catheterization accounted for 4% of radiation encounters but comprised 78% of total radiation exposure. In a multivariate model, factors associated with increased total radiation exposure included pulmonary artery (PA) stenosis requiring intervention (p = 0.005) and systemic right ventricle (p = 0.02). Risk factors for increased exposure from catheterization included heterotaxy syndrome (p = 0.007), re-coarctation (p = 0.003), and PA stenosis (p = 0.02). At our institution, many single ventricle patients are exposed to substantial radiation throughout staged palliation, most of which derives from cardiac catheterization. PA stenosis was identified as a risk factor for increased total and catheterization-based exposure. As patient survival improves, awareness of this scale of radiation exposure at a vulnerable period is imperative.

Cumulative Radiation Exposure and Cancer Risk Estimation in Children With Heart Disease

Children with heart disease are frequently exposed to imaging examinations that use ionizing radiation. Although radiation exposure is potentially carcinogenic, there are limited data on cumulative exposure and the associated cancer risk. We evaluated the cumulative effective dose of radiation from all radiation examinations to estimate the lifetime attributable risk of cancer in children with heart disease. Children ≤6 years of age who had previously undergone 1 of 7 primary surgical procedures for heart disease at a single institution between 2005 and 2010 were eligible for the study. Exposure to radiation-producing examinations was tabulated, and cumulative effective dose was calculated in millisieverts. These data were used to estimate lifetime attributable risk of cancer above baseline using the approach of the Committee on Biological Effects of Ionizing Radiation VII. The cohort included 337 children exposed to 13 932 radiation examinations. Conventional radiographs represented 92% of examinations, whereas cardiac catheterization and computed tomography accounted for 81% of cumulative exposure. Overall median cumulative effective dose was 2.7 mSv (range, 0.1-76.9 mSv), and the associated lifetime attributable risk of cancer was 0.07% (range, 0.001%-6.5%). Median lifetime attributable risk of cancer ranged widely depending on surgical complexity (0.006%-1.6% for the 7 surgical cohorts) and was twice as high in females per unit exposure (0.04% versus 0.02% per 1-mSv effective dose for females versus males, respectively; P<0.001). Overall radiation exposures in children with heart disease are relatively low; however, select cohorts receive significant exposure. Cancer risk estimation highlights the need to limit radiation dose, particularly for high-exposure modalities.

Cumulative exposure to medical sources of ionizing radiation in the first year after pediatric heart transplantation

Pediatric heart transplant recipients undergo a variety of radiologic tests with the attendant risk of exposure to ionizing radiation. We sought to quantify and describe the cumulative exposure to all forms of medical radiation during the first year after pediatric heart transplantation and identify factors associated with higher exposure. Pediatric patients who received a heart transplant between January 2009 and May 2012 with follow-up at our institution were retrospectively reviewed. Patients were included if they survived through 1 year and the first coronary angiography. All medical testing using ionizing radiation performed during follow-up was compiled, and exposures were converted to effective dose (mSv). Included were 31 patients who underwent heart transplantation at a median age of 13.6 years (range, 0.3-18.3 years). The median number of radiologic tests performed was 38 (range, 18-154), including 8 catheterizations (range, 2-12), and 28 X-ray images (range, 11-135). Median cumulative effective dose was 53.5 mSv (range, 10.6-153.5 mSv), of which 91% (range, 34%-98%) derived from catheterizations, 31% (range, 8%-89%) of the exposure occurred during the transplant admission, 59% (range, 11%-88%) during planned follow-up, and 3% (0%-56%) during unplanned follow-up. Older age at transplant was a risk factor for increased exposure (p = 0.006). When adjusted for age, a trend toward increased exposure was shown for congenital heart disease as the indication for transplant (p = 0.08), pre-sensitization (p = 0.12), and positive crossmatch (p = 0.09). Pediatric heart transplant patients are exposed to significant amounts of ionizing radiation during the first post-transplant year, most during scheduled catheterization. As survival improves, considering the long-term risks associated with these levels of exposure is important.

Radiation Exposure from Diagnostic Imaging Studies Among Patients with Inflammatory Bowel Disease in a Safety-Net Health-Care System

Radiographic imaging studies are important in the management of patients with inflammatory bowel disease (IBD), but are associated with radiation exposure. IBD patients in a safety-net health-care system may be at risk of high exposure to radiation. Our purpose was to identify associations of high-dose radiation exposure among an ethnically diverse cohort of IBD patients in a safety-net health-care system. A study was performed on patients with IBD receiving care from the Harris County Hospital District. Radiation exposure was calculated using total number of imaging studies performed between from 2000 and 2010 and estimates of radiation dose per study. Associations of high-dose radiation exposure, defined as a cumulative effective dose (CED) >50 mSv, were identified by using univariate and multivariate logistic regression. The study cohort of 278 patients with IBD was ethnically diverse, with 30 % Caucasian, 44 % African-American, and 26 % Hispanic. The median CED was 10.40 mSv (SD 20.02). Annualized radiation doses were 3.45 mSv/year among patients with Crohn's disease (CD) and 1.27 mSv/year among patients with ulcerative colitis, p < 0.02. Approximately 13 % of IBD patients received a CED >50 mSv. There were no differences in radiation exposure based on age, gender, or race/ethnicity. A small proportion of IBD patients in a safety-net health-care system received high doses of diagnostic radiation exposure. Use of diagnostic imaging studies that limit radiation exposure should be encouraged.