Mean Cumulative Effective Dose Research Articles

Increased cancer incidence in children after cardiac catheterization within the first 8 years of life, a single center experience between 1999 and 2013

Abstract 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

Cervical and lumbar spine imaging after traffic and occupational accidents: Evaluation of the use of imaging techniques, cumulative radiation dose and associated lifetime cancer risk

PurposeTo study number and type of imaging techniques, cumulative radiation exposure and radiation-induced risk from repeated imaging of cervical and lumbar spine attained after traffic or occupational accident. MethodThe study cohort comprised of 500 patients after traffic or occupational accident. Amount of radiography, CT and MRI procedures and injury severity were tallied for each patient. Cumulative effective dose (CED), expressed in millisieverts (mSv), was estimated by summing up typical effective dose values. Total lifetime cancer risks and associated risk category were estimated by using risk coefficients, specified according to sex, age at exposure and exposed region. ResultsA total of 2,107 imaging procedures were performed of which 30% were radiographs (n = 631), 21% were CT (n = 438) and 49% were MRI (n = 1,038). Abbreviated Injury Scale was low (1–2) in all cases (except one). The cohort included 352 patients after traffic accident and 148 after occupational accident. Mean CED of these two groups were 4.4 mSv and 9.4 mSv, respectively. No patient had a CED higher than 100 mSv. Nineteen patients fell into the ‘moderate risk’ group, meaning that the additional risk of fatal cancer from accumulated radiation exposure lies between 1 in 1,000 and 1 in 100. ConclusionsMRI was the most used imaging technique. No CED from repeated imaging procedures after minor or moderate traffic or occupational accident exceeded 100 mSv. However, nineteen patients fell into the ‘moderate risk’ group of developing radiation-induced cancer. Tracking radiation exposure can be beneficial in identifying those with high CED, although education on its proper use is necessary.

A comparison of Low Dose with Standard Dose Chest CT Scan in Diagnosis of COVID-19

Aim: Comparison of safety profile of low dose CT scan chest with standard dose CT scan in Covid 19. Study design: Prospective study Place and duration of study: Department of Radiology, Benazir Bhutto Hospital, Rawalpindi from -01-09-2020 to 31-03-2021. Methods After approval from ERB, 45 COVID-19 positive patients diagnosed by PCR, aged 55 years and above were selected. In the prospective study, these patients with normal CXR were advised for same day chest CT scan. Initially, a standard dose of chest CT scan of 150mAs was applied. After assessing the chest signs of Covid on scan, a low-dose CT of 30mAs was performed instantly. A comparison was made to check the diagnostic accuracy of standard-dose and low-dose CT for the identification of features of typical COVID19 pneumonia. Results: The mean age of patients was 58.27±7.23. An admirable intra-reader agreement was found between low- and standard-dose CT in identifying typical findings of COVID pneumonia (intraclass correlation coefficient [ICC] = 0.98–0.99 with A p value of less than 0.001 of all readers). Mean effective dose values of low and standard dose groups were 1.69±0.38 mSv and 7.21±1.23, correspondingly. Values of absolute cancer risk per mean cumulative effective dose of low & standard dose chest CT examinations were 0.68 × 10−4 and 2.41×10−4 respectively. Conclusions: The low dose CT chest protocol is better than standard dose for the identification of typical COVID-19 pneumonia features in routine practice with substantial decrease in dose of radiation as well as estimated cancer risk. Keywords: SARS CoV 2, Diagnosis, CT scan, Safety profile

Cumulative Effective Dose from Medical Imaging in Inflammatory Bowel Disease.

Inflammatory bowel diseases (IBD) are chronic and relapsing disorders usually requiring numerous medical imaging. IBD patients might be exposed to a large dose of radiation. As a cumulative effective dose (CED) ≥ 50 mSv is considered significant for stochastic risks of cancer, it is important to monitor the radiation exposure of IBD patients. In the present work, we aimed to quantify the mean CED in IBD patients and identify factors associated with exposure to high doses of diagnostic radiation. A retrospective chart view of patients with IBD hospitalized between 2015 and 2019 was performed. A total of 65 patients with Crohn’s disease (CD) and 98 patients with ulcerative colitis (UC) were selected. Of all imaging studies performed, 73% were with doses of ionizing radiation. Mean CED (SD) amounted to 19.20 (15.64) millisieverts (mSv) and 6.66 (12.39) mSv, respectively, in patients with CD and UC (p < 0.00001). Only 1.84% of the patients received CED ≥ 50 mSv. We identified three factors associated with CED in the IBD patients: number of surgical procedures, and number and length of hospitalization. CD patients with strictures or penetrating disease and UC patients with extensive colitis were more likely to receive higher radiation doses.

Assessment of patients’ cumulative doses in one year and collective dose to population through CT examinations

PurposeTo estimate percentage of patients undergoing multiple CT exams leading to cumulative effective dose (CED) of more than 25, 50, 75 and 100 mSv in one year and assess per capita and the collective effective dose. MethodsData from a regional hospital network was collected retrospectively using radiation dose monitoring system at 6 facilities with 8 CT scanners. The data was analyzed to find number of patients in different dose groups, their age, gender, number of CT exams and exams needed to reach 100 mSv based on age groups. ResultsIn one year 43,010 patients underwent 75,252 CT examinations. The number of exams per 1000 population was 153. Further 27% of the patients were younger than 55- years and 15.9% of them were younger than 45-year-old. A total of 0.67% of patients received a CED > 100 mSv; 3.5% had CED > 50 mSv, 11.9% with CED > 25 mSv and the maximum CED was 529 mSv. The minimum time to reach 100 mSv was a single CT exam. Seven patients received > 100 mSv in a single CT exam. 0.36% of patients had 10 or more CT exams in one year and 3.8% had 5 or more CT exams. The mean CED was 12.3 mSv, the average individual effective dose was 1.1 mSv and the collective effective dose was 521.3 person-Sv. ConclusionsThe alarming high CED received by large number of patients and with high collective dose to population requires urgent actions by all stake holders in the best interest of patient radiation safety.

Repeated Pelvic Radiographs in Infants, After Harness Treatment for Developmental Dysplasia of the Hip, Carry Very Low Radiation Risk

ObjectiveThere are no data on the effect of X-Ray irradiation to the vulnerable pelvic organs of babies during DDH follow-up. This study aims to calculate, for the first time, the radiation exposure to infants during follow-up for DDH harness treatment, and thus quantify the lifetime risk of malignancy.MethodsPatients who had completed 5 years’ follow-up following successful Pavlik harness treatment were identified from the hospital DDH database. The radiation dose was extracted from the Computerised Radiology Information System database for every radiograph of every patient. The effective dose (ED) was calculated using conversion coefficients for age, sex and body region irradiated. Cumulative ED was compared to Health Protection Agency standards to calculate lifetime risk of malignancy from the radiographs.ResultsAll radiographs of 40 infants, successfully treated in Pavlik harness for DDH, were assessed. The mean number of AP pelvis radiographs was 7.00 (range: 6–9, mode: 7). The mean cumulative ED was 0.25 mSv (Range: 0.11–0.46, SD: 0.07). This is far lower than the annual ‘safe’ limit for healthcare workers of 20 mSv and is categorised as “Very Low Risk”.ConclusionClinicians involved in the treatment DDH can be re-assured that the cumulative radiation exposure from pelvic radiographs following Pavlik harness treatment is “Very Low Risk”. Whilst being mindful of any radiation exposure in children, this study provides a scientific answer that help addresses parental concerns.

Factors influencing cumulative radiation dose from percutaneous intra-abdominal abscess drainage in the setting of inflammatory bowel disease.

Patients with inflammatory bowel disease (IBD) are at risk for intra-abdominal abscesses requiring CT-guided drainage. These patients are at baseline risk of high cumulative radiation exposure from imaging, which may be exacerbated by CT-guided drainage. This study aimed to determine the radiation dose associated with percutaneous drainage in the setting of IBD and identify risk factors associated with high exposure. An IRB-approved single-center retrospective study was performed to identify patients with IBD who underwent percutaneous abscess drainage over a 5-year period. An episode of drainage was defined from drain placement to removal, with all intervening procedures and diagnostic CT scans included in the cumulative radiation dose. The mean cumulative effective dose for a drainage episode was 47.50mSv. The mean duration of a drainage episode was 68.7days. Patients with a cumulative dose greater than 50mSv required higher number of follow-up visits compared to patients with less than 50mSv (6.9 vs. 3.5, p = 0.003*). Patients with higher cumulative dose were also more likely to require drain upsize (54% vs. 13%, p = 0.01*) or additional drain placement (63% vs 24%, p = 0.03*) compared to patients with lower dose. Intra-abdominal abscess drainage may be associated with significant cumulative radiation exposure. Requirement of drain upsizing or additional drain placement were associated with higher cumulative radiation dose, which may be related to more severe underlying inflammatory bowel disease.

Radiation Exposure in Patients with Isolated Limb Trauma: Acceptable or Are We Imaging Too Much?

The aim of our study was to investigate the cumulative effective dose of radiation resulting from medical imaging in orthopaedic patients with isolated extremity trauma. Deidentified radiology records of consecutive patients without age restriction with isolated extremity trauma requiring operative treatment at a regional hospital were reviewed retrospectively over a 1-year period, and the effective dose per patient for each study type of plain film X-ray, computed tomography, and operative fluoroscopy was used to calculate cumulative effective dose. Values were summarised as mean, ± standard deviation, maximum, and proportion with overdose (>20 mSv). The study cohort included 428 patients (193 male and 235 female) with an average age of 44 years (±28). There were 447 procedures performed, i.e., all involved operative fluoroscopy, 116 involved computed tomography, and 397 involved X-ray. The mean cumulative effective dose per patient was 1.96 mSv (±4.98, 45.12). The mean cumulative effective dose for operative fluoroscopy was 0.32 mSv (±0.73, 5.91), for X-ray was 1.12 mSv (±3.6, 39.23) and for computed tomography was 2.22 mSv (±4.13, 20.14). The mean cumulative effective dose of 1.96 mSv falls below the recommended maximum annual exposure of 20 mSv. This study can serve as a guide for informing clinicians and patients of the acceptable radiation risk in the context of isolated extremity trauma.

A low-dose chest CT protocol for the diagnosis of COVID-19 pneumonia: a prospective study

PurposeThe increasing trend of chest CT utilization during the COVID-19 pandemic necessitates novel protocols with reduced dose and maintained diagnostic accuracy. We aimed to investigate the diagnostic accuracy of 30-mAs chest CT protocol in comparison with a 150-mAs standard-dose routine protocol for imaging of COVID-19 pneumonia.MethodsUpon IRB approval, consecutive laboratory-confirmed positive COVID-19 patients aged 50 years or older who were referred for chest CT scan and had same-day normal CXR were invited to participate in this prospective study. First, a standard-dose chest CT scan (150 mAs) was performed. Only if typical COVID-19 pneumonia features were identified, then a low-dose CT (30 mAs) was done immediately. Diagnostic accuracy of low-dose and standard-dose CT in the detection of typical COVID-19 pneumonia features were compared.ResultsTwenty patients with a mean age of 64.20 ± 13.8 were enrolled in the study. There was excellent intrareader agreement in detecting typical findings of COVID-19 pneumonia between low-dose and standard-dose (intraclass correlation coefficient [ICC] = 0.98–0.99, P values < 0.001 all readers). The mean effective dose values in standard- and low-dose groups were 6.60 ± 1.47 and 1.80 ± 0.42 mSv, respectively. Also, absolute cancer risk per mean cumulative effective dose values obtained from the standard- and low-dose CT examinations were 2.71 × 10−4 and 0.74 × 10−4, respectively.ConclusionsAccording to our study, it was found that proposed low-dose CT chest protocol is reliable in detecting COVID-19 pneumonia in daily practice with significant reduction in radiation dose and estimated cancer risk.

Differences in the clinical management of women and men after detection of a solitary pulmonary nodule in clinical practice.

To explore differences in the clinical management of men and women in the 5years after detecting a solitary pulmonary nodule (SPN) by chest radiograph or CT in routine clinical practice. We followed up 545 men and 347 women with an SPN detected by chest radiograph or CT in a retrospective cohort of 25,422 individuals undergoing routine thoracic imaging in 2010-2011. We compared the frequency of each management strategy (no further test, immediate intervention or follow up) according to sex by means of chi-squared. We estimated the relative risk of women versus men of having been followed up instead of an immediate intervention using multivariate logistic regression. We compared by sex the time between detection of the nodule and lung cancer diagnosis, the time between diagnosis and death by means of Mann-Whitney U test and the cumulative effective dose of radiation in each management strategy by means of t test. Women were more likely than men to have follow-up rather than immediate intervention (aRR = 1.8, CI 1.3-2.7, p = 0.002), particularly in those who underwent CT (aRR = 4.2, CI 1.9-9.3, p < 0.001). The median time between SPN detection and lung cancer diagnosis was higher in women (4.2months, interquartile range (IQR) 5.1) than in men (1.5months, IQR 16.2). The mean cumulative effective dose was 21.3mSv, 19.4mSv in men and 23.9mv in women (p = 0.023). Our results could reflect decisions based on a greater suspicion of lung cancer in men. The incidental detection of SPNs is increasing, and it is necessary to establish clear strategies aimed to reduce variability in their management according to patient's sex. • After incidental finding of SPN, women were less likely to receive an immediate intervention. • Accumulative radiation was higher in women than in men. • Our results could reflect decisions based on a greater suspicion of lung cancer in men.

Abstract No. 576 Factors influencing cumulative radiation dose for percutaneous intra-abdominal abscess drainage in patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are at risk for penetrating disease complications and intra-abdominal abscesses requiring CT-guided drainage. These patients are at baseline risk of high cumulative radiation exposure from diagnostic imaging, which may be exacerbated by CT-guided drainage. This study aimed to determine the radiation dose associated with percutaneous drainage and follow-up in the setting of IBD and identify risk factors associated with high exposure. An IRB-approved single-center retrospective study was performed to identify patients with IBD who underwent abscess drainage over a five-year period (2013-2018). An episode of drainage was defined from drain placement to removal, with all procedures and diagnostic CT scans included in the cumulative radiation dose. Radiation dose was reported by a monitoring database, Radimetrics (Whippany, NJ). Patients were divided into cohorts based on a cumulative effective dose of 50 mSv. Statistical analysis was performed with GraphPad Prism 8 (La Jolla, CA). Patient demographics (n = 40) are reported in Table 1. The mean cumulative effective dose for the percutaneous drainage episodes was 47.50 mSv. The mean total duration of drainage episodes was 68.7 days, with an average of 4.48 CT scans or repeat interventions during that period. Patients with a total dose greater than 50 mSv (group A) required higher number of follow-up visits compared to patients with less than 50 mSv (group B) (6.9 vs. 3.5, P = 0.003). Group A patients were more likely to require drain upsize (54% vs. 13%, P = 0.01) or repeat drain placement (63% vs. 24%, P = 0.03) after initial drainage compared to group B patients. Group B patients had significantly higher number of drains placed at initial drainage compared to group A (1.8 vs. 1.2, P = 0.002). Intra-abdominal abscess drainage may be associated with significant cumulative radiation exposure. Drain upsizing, fewer initial drains, and repeat drain placement were associated with higher dose, which demonstrates the importance of catheter caliber selection and catheter positioning at the time of initial drainage to potentially reduce overall radiation exposure.Table 1Male:female ratio20:20Average age (years, mean ± SD)42.83 ± 16.65Crohn’s disease:ulcerative colitis33:7Drainage of postoperative complication24/40 (53%) Open table in a new tab

Which patients are prone to undergo disproportionate recurrent CT imaging and should we worry?

PurposeTo identify the spectrum of patients who undergo disproportionate recurrent computed tomography (CT) imaging, and to explore the cumulative effects of radiation exposure and intravenously injected contrast agents in these patients. MethodsThis retrospective study investigated all patients who had undergone 40 or more CT scans at a tertiary care center between 2007–2017. ResultsFifty-six patients who had undergone a median of 47 (range: 40–92) CT scans were included. The main reason for CT scanning in all patients was oncological, and 55 patients (98.2 %) had metastatic disease. Twenty-six patients (45.6) had received chemotherapy, 35 (62.5 %) radiation therapy, 38 (67.9 %) targeted therapy, 12 (21.4 %) liver tumor microwave ablation, 44 (78.6 %) major surgery, and 34 (60.7 %) had participated in a therapeutic trial. Mean cumulative effective dose was 187.4 mSv (range: 120.7–278.4 mSv). Median estimated radiation-induced lifetime attributable risk (LAR) of cancer incidence was 1.0 % (range: 0.20–2.36 %). Mean estimated radiation-induced LAR of cancer mortality was 0.68 % (range: 0.18–1.37 %). Mean cumulative volume of intravenously injected iomeprol was 2339 mL (range: 540−3605 mL). Three patients (5.4 %) had developed severely decreased kidney function (estimated glomerular filtration rate between 15 and 29 mL/min per 1.73 m² for at least 3 months). ConclusionPatients with metastatic disease who experience a relatively long survival may be prone to undergo disproportionate recurrent CT imaging. The non-negligible CT radiation-induced cancer risk and mortality should be taken into account in these patients, while the effect of cumulatively administered CT contrast agents on kidney function requires further investigation.

Cumulative effective dose caused by diagnostic imaging and its associated risk for cancer development in trauma patients referred to the emergency department

Background: The current study aimed to determine the cumulative effective dose caused by diagnostic imaging and its associated risk for cancer development in trauma patients referred to an emergency department. Methods: This study was carried out retrospectively in an emergency department (Kashan, Iran) from April 2015 to October 2015. Then, the types of diagnostic radiologic studies performed on adult trauma patients in their first 24 h upon presentation were recorded. Finally, the cumulative effective dose of trauma patients and its associated risk for cancer development were obtained. Results: In total, the patients received 3323 radiologic examinations including 2169 radiographs and 1154 computed tomography (CT)-scans. The most common type of plain radiographic and CT-scan examinations included anterior posterior and posterior anterior chest as well as head, respectively. The mean cumulative effective dose received by trauma patients referred to the emergency department was 2.47 ± 4.29 mSv. Most of the effective dose was from CT-scan examinations (90.65% of total cumulative effective dose; 2181.91 mSv). The majority of patients (83.40%) received between 0.00 and 5.00 mSv cumulative effective dose. Moreover, the cancer risk per average cumulative effective dose received by trauma patients was 1.01 × 10−4. Conclusions: In current study, the mean cumulative effective dose per each trauma patient (2.47 mSv) was relatively less than that of the other evaluated studies. It was also found that although the number of CT-scans was relatively few compared to plain radiographs, most of the cumulative effective dose of patients resulted from CT-scans; hence, using unnecessary CT-scan examinations should be avoided.

CT is the main component of the global exposure to ionizing radiation for patients benefiting from a trans-femoral TAVR

X-rays are widely used for the TAVR realization, for the pre-TAVR assessment (coronary angiography ± PCI and computed tomography), and sometimes in the aftermath of the intervention (electrophysiology study, pacemaker implantation). TAVR currently becomes an alternative to surgical valve replacement for patients at intermediate risk, a population that is likely to experience an increase of the radiation-induced cancer risk following TAVR. The main objective of our study was therefore to evaluate the overall exposure to ionizing radiation for patients benefiting from a trans-femoral TAVR. All patients who underwent trans-femoral TAVR for a symptomatic aortic stenosis in our centre over a 26 months period were included. Dosimetric indicators (i.e. dose area product or dose length product) of pre-procedural coronary angiography and computed tomography, TAVR procedure, and any post-procedural interventions (electrophysiology study and/or pacemaker implantation) were collected and converted into an effective dose. The primary endpoint was the cumulative effective dose, calculated by summing effective doses received during the TAVR procedure and during pre- and post-procedural irradiating exams. One hundred and ninteen trans-femoral TAVR procedures were included, and the mean cumulative effective dose was 37.3 mSv. When only three procedures were necessary (71% of the population), 75% of the overall effective dose was from the computed tomography, while only 11% of this dose came from the TAVR procedure itself and 14% came from the coronary angiogram ( Table 1 , Fig. 1 ). Overall exposure to ionizing radiation for patients benefiting from a trans-femoral TAVR seemed acceptable, and the majority of the overall effective dose was from the computed tomography.

Exposure to Ionizing Radiation in Patients Undergoing Transfemoral Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) is currently becoming an alternative to surgical valve replacement for patients at low risk, a population that is likely to experience an increase in the radiation-induced cancer risk following TAVI. We aimed to evaluate the overall exposure to ionizing radiation in patients who underwent transfemoral TAVI, including the procedure itself as well as the procedures performed in the preintervention work-up and the post-TAVI interventions. All patients who underwent transfemoral TAVI for symptomatic aortic stenosis in our center over a 26 months period were included. Dosimetric indicators from preprocedural coronary angiography and computed tomography (CT), the TAVI procedure, and any postprocedural interventions (electrophysiology study and/or pacemaker implantation) were collected and converted into an effective dose. A total of 119 transfemoral TAVI procedures were included. The mean cumulative effective dose (ED) was 37.3 mSv. Three irradiating procedures were necessary for 84 patients (71% of the population, i.e., coronary angiography, CT scan and the TAVI procedure itself), whereas 30 patients (25%) required a fourth procedure, and 5 required a fifth (4%). The majority of the dose was from the CT, while only 11% of the dose derived from the TAVI procedure itself. In conclusion, overall exposure to ionizing radiation for patients who underwent transfemoral TAVI seems acceptable, and the majority of the overall ED comes from the CT scan.

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

Patients who underwent radiofrequency ablation of atrial fibrillation are exposed to X-rays not only during the procedure but also during the preprocedural computed tomography. No study has investigated the cumulative effective dose received by patients who underwent atrial fibrillation ablation and identified factors influencing this dose. We aimed to evaluate the overall exposure to ionizing radiation in patients who underwent radiofrequency ablation of atrial fibrillation. The secondary objective was to estimate the impact of obesity on this exposure. All patients who underwent a first attempt of radiofrequency ablation of atrial fibrillation in our center over a 21 months period were included. Dosimetric indicators from preprocedural computed tomography and the ablation procedure were collected and converted into an effective dose. A total of 144 radiofrequency ablation of atrial fibrillation were included. The mean cumulative effective dose was 11.4 mSv, and 82% of the dose was from the computed tomography. Obese patients received a dose that was 75% higher than normal-weight patients, and this increase remained significant by multivariate analysis. In conclusion, overall exposure to ionizing radiation for patients who underwent radiofrequency ablation of atrial fibrillation seems acceptable, and the majority of the overall effective dose comes from the computed tomography. Obese patients are exposed to a 75% higher dose than normal-weight patients.

Diagnostic Radiation Exposure in Patients with Inflammatory Bowel Disease.

Background Because of the chronic and relapsing nature of inflammatory bowel disease (IBD), which often requires characterization with CT scan, IBD patients might be exposed to a large amount of radiation. As a cumulative effective dose (CED) ≥ 100 mSv is considered significant for stochastic risks of cancer, it is important to monitor and control the radiation exposure of the IBD patients. In the present work, we aimed to quantify the mean CED in IBD patients to assess any harmful effects of radiation. Methods This study includes 200 IBD patients, identified retrospectively, from the outpatient clinics of the Centre Hospitalier de l'Université de Montréal between January 1, 2010, and February 15, 2017, from the gastroenterologists' patients lists. The number and type of each radiology test performed were listed for each patient during the study period and the CED was calculated using our institution's dose index when available and standardized tables. Results Among the 200 IBD patients, 157 patients had Crohn's disease (CD), 41 had ulcerative colitis (UC), and 2 had indeterminate colitis. The mean CED for IBD patients was 23.1 ± 45.2 mSv during a mean follow-up duration of 4.3 years. CED was higher among patients with CD than with UC (27.5 ± 49.5 versus 6.8 ± 14.8 mSv; p<0.01). Six patients were exposed to a high CED (>100 mSv) and all had CD. Conclusion While potentially harmful levels of radiation exposure are of concern in only a small number of patients, strategies to limit such exposure are encouraged when clinically appropriate.

Cumulative radiation dose after lung transplantation in patients with cystic fibrosis.

The purpose of this study was first to evaluate the imaging-related cumulative post-transplantation radiation dose in cystic fibrosis (CF) lung transplantation (LT) recipients and second, to identify the occurrence and type of malignancies observed after LT. A total of 52 patients with CF who underwent LT at our institution between January 2001 and December 2006 with at least 3 years of survival were retrospectively included. There were 27 men and 25 women with a mean age of 24.4±9.2 (SD) years (range: 7.6-52.9 years) at the time of LT. Calculation of cumulative effective and organ doses after LT were based on dosimetry information and acquisition parameters of each examination. Cumulative radiation doses were calculated until June 2016, but stopped at the time of de novomalignancy diagnosis, for patients developing the condition. Patients received a mean cumulative effective dose of 110.0±51.6 (SD) mSv (range: 13-261.3 mSv) over a mean follow-up of 8.1±3.6 (SD) years (range: 0.5-13.5 years), with more than 100mSv in 5 years in 19/52 patients (37%). Chest CT accounted for 73% of the cumulative effective dose. Mean doses to the lung, breast and thyroid were 152.8±61.1 (SD) mGy (range: 21.2-331.6 mGy), 106.5±43.2 (SD) mGy (range: 11.9-221.4 mGy) and 72.7±31.8 (SD) mGy (range: 9.5-165.0 mGy), respectively. Nine out of 52 patients (17%) developed a total of 10 de novo malignancies, all but one attributable to immunosuppression after a mean post-transplantation follow-up period of 11.1±3.5 (SD) years (range: 3.7-16.3 years). Six-month cumulative effective dose was not greater in patients with de novomalignancies than in those without de novomalignancies (28.9±14.5 (SD) mGy (range: 13.0-53.4) vs 25.6±15.3 (range: 5.0-69.7), respectively, P>0.05). The cumulative effective dose exceeded 100 mSv in 5 years in 37% of LT recipients, the reason why continuous efforts should be made to optimize chest CT acquisitions accounting for 73% of the radiation dose.

Technical feasibility, radiation dosimetry and clinical use of 18F-sodium fluoride (NaF) in evaluation of metastatic bone disease in pediatric population.

The role of 18F-fluoride (18F-NaF) PET-CT for the detection of bone metastases in adults is well established and is considered superior to conventional bone scintigraphy. However, data pertaining use of 18F-NaF PET-CT in pediatric oncology is relatively sparse. The aim of the present study is to retrospectively analyze and share a single-center experience of 18F-NaF PET-CT in pediatric population and to provide preliminary information regarding imaging technique, feasibility of this modality in young patients and radiation dosimetry measurements in pediatric oncology cases. Twenty-four pediatric patients (mean age 8.0 ± 3.9) were included in the study for retrospective analysis. All patients were referred for primary staging or restaging for potential osseous metastatic disease and PET-CT scan was performed by injecting 2.2MBq/kg (0.06mCi/kg) of 18F-NaF. Nine patients were imaged for primary staging and in all cases increase osteoblastic activity was seen in the primary tumor and of these, metastatic bone disease was identified in 2/9 patients. In the restaging group comprising 15/24 patients, metastatic deposits were identified in 3/15 whilst no disease was seen in the remaining 12 patients. Patients were injected a mean dose of 90.35 ± 22.9MBq with an estimated mean effective absorbed doses of 2.98 ± 0.75mSv for 18F-NaF and 3.37 ± 2.4mSv for CT alone. Mean cumulative effective dose of 18F-NaF PET-CT scan was 5.11 ± 2.7mSv. 18F-NaF PET-CT may be a feasible alternative to 99mTc MDP for radionuclide bone scintigraphy in the evaluation of pediatric bone pathology. Due to its better pharmacokinetics, there is potential that osseous staging can be achieved with relatively low doses and with a similar radiation burden as with 99mTc-MDP imaging.

Variability in Imaging Practices and Comparative Cumulative Effective Dose for Neuroblastoma and Nephroblastoma Patients at 6 Pediatric Oncology Centers.

The purpose of this study was to estimate the cumulative effective dose (CED) from diagnosis and posttherapy computed tomographic (CT) scans performed on children treated for neuroblastoma or nephroblastoma (Wilms tumor) and to examine the different imaging practices used in 6 regional pediatric oncology centers between January 2010 and December 2013. We analyzed retrospectively the CT scan acquisition data in children aged 10 years or younger at diagnosis. The use of nonionizing imaging modalities was reported. The CT examinations of 129 children, with a mean age at diagnosis of 36 months, treated for 66 neuroblastomas and 63 nephroblastomas, were analyzed. The mean follow-up period was 28 months (minimum, 8 months, maximum, 41 mo). There were 600 CT scans, with a total of 1039 acquisitions. The mean CED from CT scans was 27 mSv (minimum=18.25, maximum=45). Abdominal CT examinations contributed 85% of the total CED. A median of 4.6 CT scans, 10.3 sonograms, and 0.4 magnetic resonance imaging examinations per child were performed. Our results suggest a reduction in radiation exposure but variability in the imaging modality choice and acquisition protocols. We emphasize the need for consensus and standardization in oncologic pediatric imaging procedures. When feasible, we encourage the substitution of nonionizing examinations for CT.