Reducing Pediatric Intraoral Radiography Radiation Dose Using Reduced-Power Dental X-Ray Units: A Randomized Trial.

Purpose: To assess the diagnostic confidence of intraoral radiographic image quality while reducing the pediatric patient's radiation exposure using a longer position indicating device (PID), additional X-ray beam filtration and rectangular collimation while using modern, lower-power intraoral dental X-ray units.
Methods: A randomized prospective study scored bitewing intraoral dental images based on relevant clinical features. Observer studies with pediatric dentists and dental residents were conducted to verify whether diagnostic confidence remained unchanged after dose reduction modifications. The study involved a two-phase investigation to determine: (1) the best thickness of aluminum (Al) 2024-T3 alloy filter and (2) required increased exposure time to maintain intraoral radiographic image quality. A 30 cm PID with a rectangular collimator was used to further manage patient dose. For each phase, images from 125 patients were collected from February 2017 to September 2018 and analyzed.
Results: The results from the observer study using a 30 cm PID, 1.02 mm thick Al alloy filter, and a rectangular collimator resulted in a patient dose reduction between 64 percent (exposure time of 400 msec) to 77 percent (250 msec), without any statis- tically significant effect to the diagnostic confidence of the observers in evaluating the reduced radiation images.
Conclusion: Long recognized dose reduction methods, when implemented on a modern, low-power intraoral dental X-ray unit, do not impact confidence in bite- wing diagnostic images, but substantially reduce patient dose and should be adopted to increase patient safety, especially for children.

Radiation Dose for Pediatric CT: Comparison of Pediatric versus Adult Imaging Facilities.

Background The American College of Radiology Dose Index Registry for CT enables evaluation of radiation dose as a function of patient characteristics and examination type. The hypothesis of this study was that academic pediatric CT facilities have optimized CT protocols that may result in a lower and less variable radiation dose in children. Materials and Methods A retrospective study of doses (mean patient age, 12 years; age range, 0-21 years) was performed by using data from the National Radiology Data Registry (year range, 2016-2017) (n = 239 622). Three examination types were evaluated: brain without contrast enhancement, chest without contrast enhancement, and abdomen-pelvis with intravenous contrast enhancement. Three dose indexes-volume CT dose index (CTDIvol), size-specific dose estimate (SSDE), and dose-length product (DLP)-were analyzed by using six different size groups. The unequal variance t test and the F test were used to compare mean dose and variances, respectively, at academic pediatric facilities with those at other facility types for each size category. The Bonferroni-Holm correction factor was applied to account for the multiple comparisons. Results Pediatric radiation dose in academic pediatric facilities was significantly lower, with smaller variance for all brain, 42 of 54 (78%) chest, and 48 of 54 (89%) abdomen-pelvis examinations across all six size groups, three dose descriptors, and when compared with that at the other three facilities. For example, abdomen-pelvis SSDE for the 14.5-18-cm size group was 3.6, 5.4, 5.5, and 8.3 mGy, respectively, for academic pediatric, nonacademic pediatric, academic adult, and nonacademic adult facilities (SSDE mean and variance P < .001). Mean SSDE for the smallest patients in nonacademic adult facilities was 51% (6.1 vs 11.9 mGy) of the facility's adult dose. Conclusion Academic pediatric facilities use lower CT radiation dose with less variation than do nonacademic pediatric or adult facilities for all brain examinations and for the majority of chest and abdomen-pelvis examinations. © RSNA, 2019 See also the editorial by Strouse in this issue.

Validation of Adult Relative Radiation Levels Using the ACR Dose Index Registry: Report of the ACR Appropriateness Criteria Radiation Exposure Subcommittee.

The ACR Dose Index Registry (DIR) provides a new source of clinical radiation exposure data that has not been used previously to establish or update the relative radiation level (RRL) values in the ACR Appropriateness Criteria (AC). The results of a recent review of DIR data for 10 common CT examinations were compared with current ACR AC RRL values for the same procedures. The AC RRL values were previously determined by consensus of members of the AC Radiation Exposure Subcommittee based on reference radiation dose values from the literature (when available) and anecdotal information from individual members' clinical practices and experiences. For 7 of the 10 examination types reviewed, DIR data agreed with existing RRL values. For 3 of 10 examination types, DIR data reflected lower dose values than currently rated in the AC. The Radiation Exposure Subcommittee will revise these RRL assignments in a forthcoming update to the AC (in October 2018) and will continue to monitor the DIR and associated reviews and analyses to refine RRL assignments for additional examination types. Given recent attention and efforts to reduce radiation exposure in CT and other imaging modalities, it is likely that other examination types will require revision of RRL assignments once information from the DIR database is considered.

Using the American College of Radiology Dose Index Registry to Evaluate Practice Patterns and Radiation Dose Estimates of Pediatric Body CT.

OBJECTIVE: Imaging registries afford opportunities to study large, heterogeneous populations. The purpose of this study was to examine the American College of Radiology CT Dose Index Registry (DIR) for dose-related demographics and metrics of common pediatric body CT examinations. MATERIALS AND METHODS: Single-phase CT examinations of the abdomen and pelvis and chest submitted to the DIR over a 5-year period (July 2011-June 2016) were evaluated (head CT frequency was also collected). CT examinations were stratified into five age groups, and examination frequency was determined across age and sex. Standard dose indexes (volume CT dose index, dose-length product, and size-specific dose estimate) were categorized by body part and age. Contributions to the DIR were also categorized by region and practice type. RESULTS: Over the study period 411,655 single-phase pediatric examinations of the abdomen and pelvis, chest, and head, constituting 5.7% of the total (adult and pediatric) examinations, were submitted to the DIR. Head CT was the most common examination across all age groups. The majority of all scan types were performed for patients in the second decade of life. Dose increased for all scan types as age increased; the dose for abdominopelvic CT was the highest in each age group. Even though the DIR was queried for single-phase examinations only, as many as 32.4% of studies contained multiple irradiation events. When these additional scans were included, the volume CT dose index for each scan type increased. Among the studies in the DIR, 99.8% came from institutions within the United States. Community practices and those that specialize in pediatrics were nearly equally represented. CONCLUSION: The DIR provides valuable information about practice patterns and dose trends for pediatric CT and may assist in establishing diagnostic reference levels in the pediatric population.

Radiation Safety in Children With Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization From the Image Gently Alliance.

There is a need for consensus recommendations for ionizing radiation dose optimization during multimodality medical imaging in children with congenital and acquired heart disease (CAHD). These children often have complex diseases and may be exposed to a relatively high cumulative burden of ionizing radiation from medical imaging procedures, including cardiac computed tomography, nuclear cardiology studies, and fluoroscopically guided diagnostic and interventional catheterization and electrophysiology procedures. Although these imaging procedures are all essential to the care of children with CAHD and have contributed to meaningfully improved outcomes in these patients, exposure to ionizing radiation is associated with potential risks, including an increased lifetime attributable risk of cancer. The goal of these recommendations is to encourage informed imaging to achieve appropriate study quality at the lowest achievable dose. Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making and programmatic approaches to ensure appropriate dose monitoring. Looking ahead, there is a need for standardization of dose metrics across imaging modalities, so as to encourage comparative effectiveness studies across the spectrum of CAHD in children.

Comparison of pediatric radiation dose and vessel visibility on angiographic systems using piglets as a surrogate: antiscatter grid removal vs. lower detector air kerma settings with a grid - a preclinical investigation.

The purpose of this study was to reduce pediatric doses while maintaining or improv-ing image quality scores without removing the grid from X-ray beam. This study was approved by the Institutional Animal Care and Use Committee. Three piglets (5, 14, and 20 kg) were imaged using six different selectable detector air kerma (Kair) per frame values (100%, 70%, 50%, 35%, 25%, 17.5%) with and without the grid. Number of distal branches visualized with diagnostic confidence relative to the injected vessel defined image quality score. Five pediatric interventional radiologists evaluated all images. Image quality score and piglet Kair were statistically compared using analysis of variance and receiver operating curve analysis to define the preferred dose setting and use of grid for a visibility of 2nd and 3rd order vessel branches. Grid removal reduced both dose to subject and imaging quality by 26%. Third order branches could only be visualized with the grid present; 100% detector Kair was required for smallest pig, while 70% detector Kair was adequate for the two larger pigs. Second order branches could be visualized with grid at 17.5% detector Kair for all three pig sizes. Without the grid, 50%, 35%, and 35% detector Kair were required for smallest to largest pig, respectively. Grid removal reduces both dose and image quality score. Image quality scores can be maintained with less dose to subject with the grid in the beam as opposed to removed. Smaller anatomy requires more dose to the detector to achieve the same image quality score.

Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190.

Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, "dose-area-product" (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term "DAP-meter" has been revised to air kerma-area product (KAP) meter. The charge of TG 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the "Accuracy and Calibration of Integrated Radiation Output Indicators" which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical "meter." To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field.

Toward Large-Scale Process Control to Enable Consistent CT Radiation Dose Optimization.

OBJECTIVE: This article reviews the concepts of CT radiation dose optimization and process control, discusses how to achieve optimization and how to verify that it is consistently accomplished, and proposes strategies to move toward large-scale application. CONCLUSION: CT dose optimization is achieved when the least amount of radiation necessary is used to achieve adequate image quality. The key to consistent optimization is minimization of unnecessary variation. This minimization is accomplished through local process control mechanisms.

Dose indices: everybody wants a number.

This paper discusses the merits and weaknesses of the standard terms that have been developed to quantify CT dose: CT dose indices (CTDI), dose length product (DLP) and effective dose. The difference between the measured CTDIvol and the CTDIvol displayed on the CT scanner illustrates a clinical dilemma. Displayed CTDIvol represents the radiation dose delivered to a plastic phantom, which is significantly different from the dose delivered to the patient, depending on the size of the patient. Although effective dose is simple to calculate for an individual patient, it was never intended for this purpose. The need for a simple, appropriate method to estimate pediatric patient doses led to the development of the size-specific dose estimate (SSDE), the newest CT dose index. Here I compare SSDE and its merits to the use of effective dose to estimate patient dose. The discussion concludes with a few sample calculations and basic clinical applications of SSDE to better quantify pediatric patient dose from CT scans.

Managing radiation dose from thoracic multidetector computed tomography in pediatric patients: background, current issues, and recommendations.

This review includes an overview of the fundamental physics and dose metrics of multidetector computed tomography (MDCT), a brief summary of research concerning health effects of ionizing radiation with an emphasis on risks to children, research of dose optimization, and practical recommendations that can be implemented immediately at the radiologist's own center. It is hoped that by combining results of recent research, this review will provide valuable information for the practicing radiologist. The sections of this review were designed such that each section can be read independently or skipped depending on the level of expertise of the reader.

Prospective systematic intervention to reduce patient exposure to radiation during pediatric ureteroscopy.

PURPOSE: After prospective measurement of radiation exposure during pediatric ureteroscopy for urolithiasis, we identified targets for intervention. We sought to systematically reduce radiation exposure during pediatric ureteroscopy. MATERIALS AND METHODS: We designed and implemented a pre-fluoroscopy quality checklist for patients undergoing ureteroscopy at our institution as part of a quality improvement initiative. Preoperative patient characteristics, operative factors, fluoroscopy settings and radiation exposure were recorded. Primary outcomes were the entrance skin dose in mGy and midline dose in mGy before and after checklist implementation. RESULTS: We directly observed 32 consecutive ureteroscopy procedures using the safety checklist, of which 27 were done in pediatric patients who met study inclusion criteria. Outcomes were compared to those in 37 patients from the pre-checklist phase. Pre-checklist and postchecklist groups were similar in patient age, total operative time or patient thickness. The mean entrance skin dose and midline dose were decreased by 88% and 87%, respectively (p <0.01). Significant improvements were noted among the major radiation dose determinants, total fluoroscopy time (reduced by 67%), dose rate setting (appropriately reduced dose setting in 93% vs 51%) and excess skin-to-intensifier distance (reduced by 78%, each p <0.01). CONCLUSIONS: After systematic evaluation of our practices and implementation of a fluoroscopy quality checklist, there were dramatic decreases in radiation doses to children during ureteroscopy.

Variation in computed tomography radiation dose in community hospitals.

PURPOSE: Concerns abound regarding the radiation dose administered to children during trauma evaluations. It is important to minimize the radiation dose administered when a computed tomographic (CT) scan is performed. This study was carried out to determine the radiation dose delivered during trauma abdominal/pelvic CT scans performed in community hospitals. METHODS: Data on consecutive children transferred after abdominal/pelvic CT scan for trauma were reviewed. Dose information was retrieved directly from reports provided, or the hospital was contacted directly, and an age-standardized dose ratio was generated. RESULTS: One hundred eighty-six patients were identified, and 36 patients were excluded, leaving 150 patients from 40 different hospitals. Half received radiation doses that were less than the national 75th percentile norm, and half received radiation doses that were greater, overall ranging from 0.17 to 5.07 times. CONCLUSIONS: Radiation exposure is a concern among those who evaluate injured children. Although not performing a CT scan may be the best way to reduce the dose, when a CT scan is deemed necessary, the scanner must be adjusted to the lowest possible settings necessary to obtain the information desired. This study identified a thirty-times range of radiation dosage for CT scans performed across 40 different hospitals.

Characterization of radiation exposure and effect of a radiation monitoring policy in a large volume pediatric cardiac catheterization lab.

OBJECTIVES: This study aimed to characterize radiation dose during cardiac catheterization in congenital heart disease and to assess changes in dose after the introduction of a radiation monitoring policy. BACKGROUND: Minimizing radiation exposure is an important patient safety initiative and relatively few data are available characterizing radiation dose for the broad spectrum of congenital cardiac catheter-based interventions. METHODS: Radiation dose data were reviewed on all cases since 7/1/05 at a single large center. Procedures were classified according to 20 common case types then subdivided into five age categories. Groups with <20 cases were excluded. Radiation dose was estimated by cumulative air KERMA (mGy) and DAP (dose area product, µGym(2)) which were reported as median and interquartile range (IQR). We also examined differences in radiation dose before and after the implementation of a radiation policy. RESULTS: Between 7/1/05 and 12/10/08, 3,365 cases were identified for inclusion. Radiation dose increased with age and procedural complexity. Patients were characterized into low, medium, and high dose categories relative to each other. "Low" dose cases included isolated pulmonary or aortic valvotomy, pre-Fontan assessment, and ASD closure. "High" dose cases involved multiple procedures in pulmonary arteries or veins. After introduction of a radiation policy, there was a significant decrease in radiation dose across a variety of case types, particularly among infants and young children. CONCLUSIONS: Radiation dose in congenital cardiac catheterization varies by age and procedure type. A radiation monitoring and notification policy may have contributed to reduced radiation dose.