Changes In Radiation Exposure Research Articles

Assessing Patient Radiation Exposure in Endoscopic Retrograde Cholangiopancreatography: A Multicenter Retrospective Analysis of Procedural Complexity and Clinical Factors.

Endoscopic retrograde cholangiopancreatography (ERCP) procedures can result in significant patient radiation exposure. This retrospective multicenter study aimed to assess the influence of procedural complexity and other clinical factors on radiation exposure in ERCP. Data on kerma-area product (KAP), air-kerma at the reference point (Ka,r), fluoroscopy time, and the number of exposures, and relevant patient, procedure, and operator factors were collected from 2641 ERCP procedures performed at four university hospitals. The influence of procedural complexity, assessed using the American Society for Gastrointestinal Endoscopy (ASGE) and HOUSE complexity grading scales, on radiation exposure quantities was analyzed within each center. The procedures were categorized into two groups based on ERCP indications: primary sclerosing cholangitis (PSC) and other ERCPs. Both the ASGE and HOUSE complexity grading scales had a significant impact on radiation exposure quantities. Remarkably, there was up to a 50-fold difference in dose quantities observed across the participating centers. For non-PSC ERCP procedures, the median KAP ranged from 0.9 to 64.4 Gy·cm2 among the centers. The individual endoscopist also had a substantial influence on radiation dose. Procedural complexity grading in ERCP significantly affects radiation exposure. Higher procedural complexity is typically associated with increased patient radiation dose. The ASGE complexity grading scale demonstrated greater sensitivity to changes in radiation exposure compared to the HOUSE grading scale. Additionally, significant variations in dose indices, fluoroscopy times, and number of exposures were observed across the participating centers.

Radiation Exposure Characteristics among Healthcare Workers: Before and After Japan's Ordinance Revision.

Radioactive materials and ionizing radiation have both medical value and disease risks, necessitating radiation dose measurement and risk reduction strategies. The International Commission on Radiological Protection (ICRP) lowered the lens of the eye exposure limit, leading to Japan's revised "Ionizing Radiation Ordinance." However, the effects on radiation exposure in medical settings and compliance feasibility remain unclear. To examine the impact of the revision to the "Ionizing Radiation Ordinance" and use it for measures to reduce exposure to radiation, a comprehensive analysis was conducted on data collected from Nagasaki University Hospital, Hiroshima University Hospital, and Fukushima Medical University Hospital in 2018, 2020, and April to September 2021. This included information on age, sex, occupation, department, and monthly radiation doses of workers, aiming to assess the impact of the revision to the "Ionizing Radiation Ordinance" on radiation exposure before and after its enforcement. Out of 9,076 cases studied, 7,963 (87.7%) had radiation doses below the measurable limit throughout the year. Only 292 cases (3.2%) exceeded 1 mSv y -1 , with 9 doctors and 2 radiological technologists surpassing 5 mSv y -1 . Radiological technologists showed significantly higher doses compared to doctors, dentists, and nurses (p < 0.01), while male subjects had significantly higher exposure doses than females (p < 0.01). No significant changes in radiation exposure were observed before and after the revision of the Ionizing Radiation Ordinance; however, variations in radiation exposure control were noted, particularly among nurses and radiological technologists, suggesting the impact of the revision and the need for tailored countermeasures to reduce radiation dose in each group.

Utilization of three-dimensional fusion images with high-resolution computed tomography angiography for preoperative evaluation of microvascular decompression: patient series.

High-resolution computed tomography (CT), outfitted with a 0.25-mm detector, has superior capability for identifying microscopic anatomical structures compared to conventional CT. This study describes the use of high-resolution computed tomography angiography (CTA) for preoperative microvascular decompression (MVD) assessment and explores the potential effectiveness of three-dimensional (3D) image fusion with magnetic resonance imaging (MRI) by comparing it with traditional imaging methods. Four patients who had undergone preoperative high-resolution CTA and MRI for MVD at Osaka University Hospital between December 2020 and March 2022 were included in this study. The 3D-reconstructed images and intraoperative findings were compared. One patient underwent conventional CTA, thus allowing for a comparison between high-resolution and conventional CTA in terms of radiation exposure and vascular delineation. Preoperative simulations reflected the intraoperative findings for all cases; small vessel compression of the nerve was identified preoperatively in two cases. Compared with conventional CTA, high-resolution CTA showed superior vascular delineation with no significant change in radiation exposure. The use of high-resolution CTA with reconstructed 3D fusion images can help to simulate prior MVD. Knowing the location of the nerves and blood vessels can perioperatively guide neurosurgeons.

Increasing radiation exposure from computed tomography in liver transplant recipients over time.

To evaluate changes in radiation exposure from computed tomography (CT) among patients undergoing liver transplantation in our unit over a 10-year period. We evaluated 134 elective patients, without hepatocellular carcinoma or cholangiocarcinoma who underwent transplantation in 2007-2008 and 2017-2018. CT scans performed in our hospital up to 2years pre transplant and 1year post transplant were evaluated. There was an increase in mean estimated effective radiation dose per patient in 2017-2018 compared to 2007-2008 (77.8mSv ± 6.2 vs 56.7mSv ± 5.9, p < 0.05). This change was mainly due to an increased number of pre-transplant CT scans per patient (2.9 ± 0.3 vs 1.4 ± 0.14, p = 0.0001). High radiation dose scan protocols were more frequently used in 2017-2018, with 4-phase liver CT accounting for a larger proportion of scans both pre-transplant (61% vs 43%, p = 0.004) and post-transplant (29% vs 13%, p = 0.002). A greater proportion of patients were exposed to > 100mSv of ionising radiation in the 2017-2018 patients (29% vs 11%, p < 0.01). These figures are likely to be a significant under-estimate as they exclude other imaging modalities and CT scans performed at other institutions. Radiation exposure from diagnostic imaging has increased among liver transplant recipients at our institution over the last decade. This appears to be due to an increase in the number of CT scans performed, and a shift towards higher dose scan protocols.

How to identify high radiation burden from computed tomography: an example in obese children

BackgroundRadiation burden from the use of computed tomography (CT) imaging may not be evenly distributed. We tested whether overweight and obese children receive higher radiation burden from CT imaging. MethodsAn automated software tool (DoseWizard) assessed patient-level radiation dose from CT and merged results with clinical data from the electronic health record. CT scans of the head, chest, and abdomen/pelvis (A/P) performed at our institution from January 2013 to August 2015 on patients aged <16 y were processed using this software. Patients were categorized as overweight/obese if they had a body mass index (BMI) greater than the 85th percentile for age. Radiation exposures were compared between groups. Higher dose CT scans were identified as having a radiation dose in the top decile. Multivariate analysis identified factors associated with high-dose CT scans. ResultsAbout 7212 CT scans were included. Overweight/obese patients received similar radiation dose for head CT as compared with normal weight patients (1.51 versus 1.49 mSv, P = 0.04) but higher radiation dose for chest (1.14 versus 0.81 mSv, P < 0.001) and A/P (1.97 versus 1.43 mSv, P < 0.001). In multivariable regression models, being overweight/obese increased the odds of a higher dose chest CT (odds ratio 2.24, P < 0.001) and A/P CT (odds ratio 7.24, P < 0.001). ConclusionsOverweight and obese children receive higher radiation burden from CT imaging and are one group that deserves consideration of dose monitoring. This software tool can be used to measure changes in radiation exposure and run clinical decision support in future studies targeting high radiation exposure to children.

Image Noise, CNR, and Detectability of Low-Contrast, Low-Attenuation Liver Lesions in a Phantom: Effects of Radiation Exposure, Phantom Size, Integrated Circuit Detector, and Iterative Reconstruction

Purpose To assess image noise, contrast-to-noise ratio (CNR) and detectability of low-contrast, low-attenuation liver lesions in a semianthropomorphic phantom by using either a discrete circuit (DC) detector and filtered back projection (FBP) or an integrated circuit (IC) detector and iterative reconstruction (IR) with changes in radiation exposure and phantom size. Materials and Methods An anthropomorphic phantom without or with a 5-cm-thick fat-mimicking ring (widths, 30 and 40 cm) containing liver inserts with four spherical lesions was scanned with five exposure settings on each of two computed tomography scanners, one equipped with a DC detector and the other with an IC detector. Images from the DC and IC detector scanners were reconstructed with FBP and IR, respectively. Image noise and lesion CNR were measured. Four radiologists evaluated lesion presence on a five-point diagnostic confidence scale. Data analyses included receiver operating characteristic (ROC) curve analysis and noninferiority analysis. Results The combination of IC and IR significantly reduced image noise (P < .001) (with the greatest reduction in the 40-cm phantom and at lower exposures) and improved lesion CNR (P < .001). There was no significant difference in area under the ROC curve between detector-reconstruction combinations at fixed exposure for either phantom. Reader accuracy with IC-IR was noninferior at 50% (100 mAs [effective]) and 25% (300 mAs [effective]) exposure reduction for the 30- and 40-cm phantoms, respectively (adjusted P < .001 and .04 respectively). IC-IR improved readers' confidence in the presence of a lesion (P = .029) independent of phantom size or exposure level. Conclusion IC-IR improved objective image quality and lesion detection confidence but did not result in superior diagnostic accuracy when compared with DC-FBP. Moderate exposure reductions maintained comparable diagnostic accuracy for both detector-reconstruction combinations. Lesion detection in the 40-cm phantom was inferior at smaller exposure reduction than in the 30-cm phantom. (©) RSNA, 2016 Online supplemental material is available for this article.

Anti-TNF Therapy Is Associated with Decreased Imaging and Radiation Exposure in Patients with Crohnʼs Disease

Diagnostic imaging is frequently used in Crohn's disease (CD) for diagnosis, evaluation of complications, and determination of response to treatment. Patients with CD are at risk for high radiation exposure in their lifetime. The aim of our study was to compare the effective dose of radiation in CD patients the year prior to and the year after initiation of anti-tumor necrosis factor (anti-TNF) agents or corticosteroids. We conducted a retrospective review of 99 CD patients initiated on anti-TNF therapy or corticosteroids between 2004 and 2009 in a tertiary care center. Sixty-five patients were initiated on anti-TNF agents and 34 were initiated on corticosteroids. The anti-TNF cohort was significantly younger at diagnosis and at the time of initiation of anti-TNF or steroid therapy. The anti-TNF group had significantly more stricturing, penetrating, and perianal disease than the corticosteroid group. The anti-TNF cohort had a significant reduction in number of radiologic exams (5.5 vs. 3.7, P < 0.01) as well as a significant reduction in the cumulative radiation dose (28.1 vs. 15.0 mSv, P < 0.01) the year after initiation of therapy. This reduction was largely attributable to decreased use of computed tomography (CT) scans. In contrast, there was no significant change in radiation exposure in the corticosteroid cohort. Logistic regression analysis showed a strong trend toward higher exposure in patients with complicated disease behavior (stricturing or penetrating phenotype) (odds ratio [OR] 2.87, 95% confidence interval [CI] 0.98-8.38). Initiation of anti-TNF therapy for treatment of CD is associated with a significant reduction in diagnostic radiation exposure. Conversely, steroid treatment does not reduce diagnostic radiation exposure.

Increasing thyroid cancer incidence in Canada, 1970–1996: time trends and age-period-cohort effects

We examined time trends in thyroid cancer incidence in Canada by age, time period and birth cohort between 1970 and 1996. Age-specific incidence rates by time period and birth cohort were calculated and age-period-cohort modelling used to estimate effects underlying the observed trends. Overall age-adjusted incidence rates of thyroid cancer doubled, from 3.3 and 1.1 per 100 000 in 1970–72 to 6.8 and 2.2 per 100 000 in 1994–96, among females and males respectively. Almost all the increase between 1970–72 and 1994–96 was due to papillary carcinoma of the thyroid. Age, birth cohort and period effects significantly improved the fit of the model for females, while age and birth cohort effects were significant determinants of the incidence among males. There were significant differences in the patterns/curvature for age, period and birth cohort effects between women and men. Our results suggest that the increases in thyroid cancer incidence in Canada may be associated with more intensive diagnostic activities and change in radiation exposure in childhood and adolescence. Temporal changes in reproductive factors among young women may explain some of the gender differences observed. © 2001 Cancer Research Campaign