Effective dose estimation for pediatric upper gastrointestinal examinations using an anthropomorphic phantom set and metal oxide semiconductor field-effect transistor (MOSFET) technology

Age-specific Dose Catalog for Diagnostic Fluoroscopy and Fluoroscopically Guided Interventional Procedures from a Pediatric Hospital

Background Fluoroscopy is an imaging modality associated with a wide range of dose levels, characterized using a variety of dose metrics, including effective dose. However, for clinical procedures, effective dose is a seldom-used and unregulated metric in the United States, and thus, it is not extensively studied in radiology despite potentially large clinical implications for patients, especially children and infants. Purpose To formulate and report a dose catalog across all diagnostic and interventional radiology (IR) fluoroscopy examination or procedure types at a specialized tertiary care pediatric hospital. Materials and Methods In this retrospective study, dose metrics taken from radiation dose structured reports of fluoroscopy between October 2014 and March 2023 were analyzed. The reports included fluoroscopy across 18 diagnostic examination types and 24 IR procedure types. The National Cancer Institute dosimetry system for Radiography and Fluoroscopy Monte Carlo software was used to estimate age-specific effective dose from dose-area product (DAP). The DAP-to-effective dose conversion factors were estimated per IR procedure type and diagnostic fluoroscopy examination type based on age. Results A total of 11 536 individual diagnostic fluoroscopy examinations (18 types) and 8017 individual IR procedures (24 types) were analyzed. Median effective dose values per diagnostic fluoroscopy examination type ranged from 0.0010 to 0.44 mSv (mean, 0.0808 mSv ± 0.0998 [SD]). Calculated DAP-to-effective dose conversion factors ranged from 0.04 to 2.48 mSv/Gy · cm2 (mean, 0.758 mSv/Gy · cm2 ± 0.614) across all diagnostic fluoroscopy examination types. Median effective dose values per IR procedure type ranged from 0.0007 to 3.90 mSv (mean, 0.6757 mSv ± 0.8989). Calculated DAP-to-effective dose conversion factors ranged from 0.001 to 0.87 mSv/Gy · cm2 (mean, 0.210 mSv/Gy · cm2 ± 0.235) across all IR procedure types. Conclusion A pediatric fluoroscopy dose catalog was created, including age-specific effective dose, using a repeatable robust method based on accurate clinical data. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Borrego and Balter in this issue.

Can the Third Part of Duodenum Behind SMA Be Detected With Confidence on CT as a Proposed Mechanism for Imaging Suspected Malrotation in Children? A Preliminary Proof of Concept Study

AIM

The aims of this study were to determine frequency and reliability of computed tomography (CT) detection of anatomic landmarks for imaging suspected midgut malrotation in infants and children, and to calculate an estimated effective dose of an upper abdominal CT scan in our patient population.

MATERIALS AND METHODS

Fifty consecutive pediatric patients who underwent a CT scan that included their upper abdomen between August 2016 and February 2018 were included. Four pediatric radiology consultants independently reviewed CT scans for detection of the third part of the duodenum and defined their confidence level of this through identification of continuity with the pyloric antrum, D1, D2, and D4 components of the duodenum, as well as the duodenojejunal flexure.Interobserver variability was assessed using Fleiss κ for agreement. A dose estimate, per scan, was calculated using the scanner dose-length product and published conversion factors by Deak.

RESULTS

Thirty patients were boys. The average age was 7.5 ± 5.4 years (6 days to 16 years). The D3 segment was definitely identified in 70% of scans, with 68% to 73%, moderate agreement between the readers and a Fleiss κ of 0.47 to 0.52. The DJ flexure was definitely identified in only 30.5% cases, with 35%, poor agreement between readers (Fleiss κ of 0.03). The average estimated dose for a targeted CT scan of the abdomen was 0.9 mSv (0.04-2.4 mSv).

CONCLUSIONS

The third part of the duodenum, which is integral in excluding malrotation on cross-sectional studies, was "definitely" identified in 70% of CT scans of children in our study, with 68% to 73% agreement between the readers and a Fleiss κ of 0.47 to 0.52.These preliminary proof of concept results demonstrating a combination of a comparable CT dose in relation to upper gastrointestinal contrast studies and an acceptable number of cases delineating the third part of the duodenum with moderate agreement are a first step in suggesting low-dose CT for an imaging diagnosis of malrotation. Malrotation can be excluded in cases where D3 is well demonstrated in the normal position, which negates the need to automatically refer children with bilious emesis to specialist centers for upper gastrointestinal contrast studies.

Harmonisation of imaging protocols, radiation doses and image quality in gastrointestinal fluoroscopy examinations - multicentre study

BACKGROUND

Paediatric gastrointestinal fluoroscopy examinations can impart varying amounts of radiation for the same patient size and exam type.

OBJECTIVE

To investigate the variability of imaging protocol, radiation dose and image quality in paediatric fluoroscopy examinations in order to provide recommendations for the harmonisation and optimisation of local practices.

MATERIALS AND METHODS

Five paediatric radiology departments performing fluoroscopically-guided contrast enema, micturating cystourethrography and upper gastrointestinal tract examinations participated in this study. Information on imaging protocols and radiation doses was retrospectively collected for more than 2,400 examinations. Image quality was analysed on clinical and phantom images.

RESULTS

Patient doses showed great variability among centers with up to a factor of 5 for similar fluoroscopy times. The five departments had imaging protocols with major differences in fluoroscopy dose regulation curves and additional filtration. Image quality analysis on phantoms and patients images showed no major improvement in contrast, spatial resolution or noise when increasing the radiation dose. Age-based diagnostic reference levels using both dose area product and fluoroscopy time were proposed per procedure type.

CONCLUSION

Disparities between centers and no correlation of radiation dose with image quality criteria create margins for optimisation. These results highlight the need for guidelines on fluoroscopy image quality and dose reference levels in paediatric gastrointestinal examinations to harmonise practices and optimise patient dose.

Mesenteric Vessel Abnormalities Detected With Sonography: A Possible Gateway to the Early Diagnosis of Various Gastrointestinal Anomalies

Background:

In pediatric sonography, mesenteric vessel abnormalities can be used as a sign of malrotation or volvulus. This study was aimed at evaluating the diseases associated with mesenteric vessel abnormalities in children, except for rotational anomalies.

Methods:

From 2017 to 2020, pediatric patients with abdominal complaints were referred for a full abdominal sonogram and were evaluated for mesenteric vascular abnormalities. During this period, 62 children (aged <12 years), with mesenteric vessel abnormalities, were discovered with sonography. They were also examined for associated anomalies and were followed until a final diagnosis was determined.

Results:

Mesenteric vessel displacement was reported in 37 patients (60%); in 24 cases, the vein was located to the left of superior mesenteric artery (SMA), and in others (13 cases), in the anterior position. Abnormal pathways in mesenteric vessels were reported in 33 patients (53%); 18 cases showing a right side turn and 15 cases showing a left side turn. The whirlpool sign was seen in 16 patients (27%). These three patterns of vessel abnormality were associated with disorders such as diaphragmatic hernia, bowel obstruction, and space occupying lesions (masses). The location of the mesenteric abnormality was in the proximal part of mesenteric vessels in 45 cases (72.5%) and in its distal part in 17 cases (27.5%). Malrotation (eight cases), obstruction, and volvulus were the most common causes of a distal abnormality.

Conclusions:

Mesenteric vessel abnormalities, noted with sonography, may not be exclusive to the diagnosis of malrotation and midgut volvulus. In this cohort, bowel obstruction, diaphragmatic hernia, and space occupying lesions were the other most common anomalies associated with mesenteric vessel abnormalities. In reviewing one-third of mesenteric vessels, abnormalities were only seen in the distal part of vessels; therefore, a thorough examination is warranted.

Upper gastrointestinal series in children: what surgeons need to know

Background

Upper gastrointestinal (UGI) series is the standard imaging tool for diagnosis of structural and functional abnormalities affecting the esophagus, stomach, and proximal small bowel. The aim of this study was to delineate the clinical indications for UGI series in children that are associated with the presence of significant radiological abnormalities aiming for more standardized care for those patients.

Results

UGI series of 118 patients was analyzed with calculation of clinical score. Vomiting was the most frequent primary complaint (63.6%), followed by dysphagia and recurrent chest infection. Forty-nine patients had positive upper GI findings (42%). The most detected abnormality was related to the stomach and duodenum (21.4%). Variable degrees of idiopathic gastroesophageal reflux were detected in 16 patients (13.6%). Patients with clinical score 2 or more had significantly more prevalence of abnormal findings (p = .001). Vomiting (especially when bilious), underweight, aspiration, and recurrent chest infection were strong predictors of abnormal findings on upper GI series (p = 0.007, 0.001, 0.009, and 0.001, respectively) and increased the diagnostic yield of upper GI series for detection of abnormalities by 3.48, 9.6, 4, and 4.12 times, respectively.

Conclusion

Diagnostic yield of UGI series was relatively higher in patients having two or more symptoms (clinical score 2 or more) and in children with bilious vomiting, aspiration and underweight, or repeated chest infection.

A Scalable Database of Organ Doses for Common Diagnostic Fluoroscopy Procedures of Children: Procedures of Historical Practice for Use in Radiation Epidemiology Studies

Assessment of health effects from low-dose radiation exposures in patients undergoing diagnostic imaging is an active area of research. High-quality dosimetry information pertaining to these medical exposures is generally not readily available to clinicians or epidemiologists studying radiation-related health risks. The purpose of this study was to provide methods for organ dose estimation in pediatric patients undergoing four common diagnostic fluoroscopy procedures: the upper gastrointestinal (UGI) series, the lower gastrointestinal (LGI) series, the voiding cystourethrogram (VCUG) and the modified barium swallow (MBS). Abstracted X-ray film data and physician interviews were combined to generate procedure outlines detailing X-ray beam projections, imaged anatomy, length of X-ray exposure, and presence and amount of contrast within imaged anatomy. Monte Carlo radiation transport simulations were completed for each of the four diagnostic fluoroscopy procedures across the 162-member (87 males and 75 females) University of Florida/National Cancer Institute pediatric phantom library, which covers variations in both subject height and weight. Absorbed doses to 28 organs, including the active marrow and bone endosteum, were assigned for all 162 phantoms by procedure. Additionally, we provide dose coefficients (DCs) in a series of supplementary tables. The DCs give organ doses normalized to procedure-specific dose metrics, including: air kerma-area product (µGy/mGy · cm2), air kerma at the reference point (µGy/µGy), number of spot films (SF) (µGy/number of SFs) and total fluoroscopy time (µGy/s). Organs accumulating the highest absorbed doses per procedure were as follows: kidneys between 0.9-25.4 mGy, 1.1-16.6 mGy and 1.1-9.7 mGy for the UGI, LGI and VCUG procedures, respectively, and salivary glands between 0.2-3.7 mGy for the MBS procedure. Average values of detriment-weighted dose, a phantom-specific surrogate for the effective dose based on ICRP Publication 103 tissue-weighting factors, were 0.98 mSv, 1.16 mSv, 0.83 mSv and 0.15 mSv for the UGI, LGI, VCUG and MBS procedures, respectively. Scalable database of organ dose coefficients by patient sex, height and weight, and by procedure exposure time, reference point air kerma, kerma-area product or number of spot films, allows clinicians and researchers to compute organ absorbed doses based on their institution-specific and patient-specific dose metrics. In addition to informing on patient dosimetry, this work has the potential to facilitate exposure assessments in epidemiological studies designed to investigate radiation-related risks.

A scalable database of organ doses for common diagnostic fluoroscopy examinations of children: procedures of current practice at the University of Florida

Of all the medical imaging modalities that utilize ionizing radiation, fluoroscopy proves to be the most difficult to assess values of patient organ dose owing to the dynamic and patient-specific nature of the irradiation geometry and its associated x-ray beam characteristics. With the introduction of the radiation dose structured report (RDSR) in the mid-2000s, however, computational tools have been developed to extract patient and procedure-specific data for each irradiation event of the study, and when coupled to a computational phantom of the patient, values of skin and internal organ dose may be assessed. Unfortunately, many legacy and even current diagnostic fluoroscopy units do not have RDSR reporting capabilities, thus limiting these dosimetry reporting advances. Nevertheless, knowledge of patient organ doses for patient care, as well as for radiation epidemiology studies, remains a research and regulatory priority. In this study, we created procedural outlines which document all radiation exposure information required for organ dose assessment, akin to a reference RDSR, for six common diagnostic fluoroscopy procedures performed at the University of Florida (UF) Shands Pediatric Hospital. These procedures include the voiding cystourethrogram, the gastrostomy-tube placement, the lower gastrointestinal study, the rehabilitation swallow, the upper gastrointestinal study, and the upper gastrointestinal study with follow through. These procedural outlines were used to develop an extensive database of organ doses for the 162-member UF/NCI (National Cancer Institute) library of pediatric hybrid phantoms, with each member varying combinations of sex, height, and weight. The organ dose assessment accounts for the varying x-ray fields, fluoroscopy time, relative concentration of x-ray contrast in the organs, and changes in the fluoroscope output due to patient size. Furthermore, we are also reporting organ doses normalized to total fluoroscopy time, reference point air kerma, and kerma-area product, effectively providing procedure dose coefficients. The extensive organ dose library produced in this study may be used prospectively for patient organ dose reporting or retrospectively in epidemiological studies of radiation-associated health risks.

Esophageal transit scintigraphy in children: a user's guide and pictorial review

Technical and clinical aspects of esophageal transit scintigraphy in pediatric patients are reviewed via several illustrative cases that highlight its utility in evaluating primary and secondary esophageal motility disorders.

Protecting sensitive patient groups from imaging using ionizing radiation: effects during pregnancy, in fetal life and childhood

The frequency of imaging examinations requiring radiation exposure in children (especially CT) is rapidly increasing. This paper reviews the current evidence in radiation protection in pediatric imaging, focusing on the recent knowledge of the biological risk related to low doses exposure. Even if there are no strictly defined limits for patient radiation exposure, it is recommended to try to keep doses as low as reasonably achievable (the ALARA principle). To achieve ALARA, several techniques to reduce the radiation dose in radiation-sensitive patients groups are reviewed. The most recent recommendations that provide guidance regarding imaging of pregnant women are also summarized, and the risk depending on dose and phase of pregnancy is reported. Finally, the risk-benefit analysis of each examination, and careful communication of this risk to the patient, is emphasized.

Identification of clinical parameters to increase the diagnostic yield of the non-emergent upper gastrointestinal series in pediatric outpatients

BACKGROUND

Outpatient, non-emergent upper gastrointestinal (GI) series are frequently requested in children with no surgical history who have nonspecific symptoms such as abdominal pain, failure to thrive and vomiting. The positive yield of an upper GI series in these patients, and, thus, its utility, has not been studied.

OBJECTIVES

We evaluated the incidence of positive upper GI findings in children without a history of GI pathology or abdominal surgery in order to identify clinical indications associated with a greater diagnostic yield.

MATERIALS AND METHODS

Findings of upper GI series performed between October 2015 and October 2017 in three institutions in children younger than 18 years of age were retrospectively reviewed. The upper GI series protocol for each institution was also reviewed. Children with a medical or surgical GI history, children with insufficient history in the chart and those with an incomplete upper GI series were excluded from the study. Exam indications, patient demographics and clinical history were obtained from the electronic medical records.

RESULTS

Of 1,267 children who underwent outpatient upper GI series, 720 (median age: 2 years) had no GI history and were included in the study. The most common indications were non-bilious vomiting (62%), reflux symptoms (28%) and abdominal pain (20%). Upper GI series were normal in 605/720 cases (84%), including 25/26 children with reported bilious emesis. Of the 115 positive studies, 78 (68%) showed only gastroesophageal reflux (GER) (median age: 11 months). Of the remaining 37 studies, 19 demonstrated esophageal findings. One case of malrotation without midgut volvulus was identified in a patient who presented with dysphagia and reflux symptoms. Using a multinomial logistic regression model and adjusting for other variables, reflux symptoms and younger patient age were independent predictors of GER on upper GI series (relative risk ratios of 2.2 and 0.9, respectively). Dysphagia and/or foreign body sensation and older patient age were independent predictors of the presence of esophageal findings (relative risk ratios of 3.3 and 1.1, respectively).

CONCLUSION

The yield of routine upper GI series in children with nonspecific symptoms, such as abdominal pain and vomiting, and no surgical history is low. Diagnostic yield was improved in older children and in those complaining of dysphagia and/or foreign body sensation. Routine upper GI series should be avoided in clinically well children with symptoms only of uncomplicated GER and no significant GI history. In children with a history of dysphagia and/or foreign body sensation, an esophagram/barium swallow can suffice.

Mimics of malrotation on pediatric upper gastrointestinal series: a pictorial review

Intestinal malrotation is a continuum of congenital anomalies due to lack of rotation or incomplete rotation of the fetal intestine around the superior mesenteric artery axis. The abnormal bowel fixation (by mesenteric bands) or absence of fixation of portions of the bowel increases the risk of bowel obstruction, acute or chronic volvulus, and bowel necrosis. The clinical presentation of patients with malrotation without, with intermittent, or with chronic volvulus can be problematic, with an important minority presenting late or having atypical or chronic symptoms, such as intermittent vomiting, abdominal pain, duodenal obstruction, or failure to thrive. The diagnosis is heavily reliant on imaging. Upper GI series remain the gold standard with the normal position of the duodenojejunal junction lateral to the left-sided pedicles of the vertebral body, at the level of the duodenal bulb on frontal views and posterior (retroperitoneal) on lateral views. However, a variety of conditions might influence the position of the duodenojejunal junction, potentially leading to a misdiagnosis of malrotation. Such conditions include improper technique, gastric over distension, splenomegaly, renal or retroperitoneal tumors, liver transplant, small bowel obstruction, the presence of properly or malpositioned enteric tubes, and scoliosis. All of these may cause the duodenojejunal junction to be displaced. We present a series of cases highlighting conditions that mimic malrotation without volvulus to increase the practicing radiologist awareness and help minimize interpretation errors.

Identifying intestinal malrotation on magnetic resonance examinations ordered for unrelated indications

BACKGROUND

Anatomical imaging findings indicating normal bowel rotation can be identified on cross-sectional imaging, including magnetic resonance imaging (MRI) performed for non-related indications.

OBJECTIVE

The goal of our study was to assess whether non-targeted MRI can accurately assess intestinal malrotation.

MATERIALS AND METHODS

Four anatomical landmarks were assessed on MRIs of the chest, spine or abdomen performed from January 2006 to June 2014, on patients who also had upper gastrointestinal series (UGI) performed within 10 years of the MRI date: 1) retroperitoneal duodenum, 2) left upper quadrant duodenojejunal junction, 3) superior mesenteric artery to the left of the superior mesenteric vein, and 4) right lower quadrant cecum. Two attending radiologists, one pediatric and one abdominal radiologist, independently reviewed the MR images. The pediatric radiologist reviewed images from UGI (considered the gold standard) to determine the intestinal rotation for each case. Validation of the criteria was performed on new patients imaged through January 2016.

RESULTS

The original cohort included 109 MRIs (15 chest, 41 spine and 53 abdomen) done on 109 patients (42% males, mean age: 10.2 years). If each of the 4 anatomical questions were answered "yes" (4-YES), specificity was 100% for each radiologist and malrotation was appropriately excluded. Using the 4-YES criteria, the pediatric radiologist excluded malrotation in 71 patients (65%) and the abdominal radiologist excluded it in 65 (60%), with concurrence for 57 patients. Validation of the 4-YES criteria in 23 new patients appropriately proved the 4-YES rule, with neither labeling the one new malrotation case 4-YES.

CONCLUSION

If a radiologist can confidently answer "yes" to the four questions evaluated in this study, then intestinal rotation can be safely considered normal. Normal bowel rotation should be commented upon in MRI reports when these four anatomical locations are imaged, thus helping patients avoid unnecessary UGI and radiation exposure.

Radiation exposure contribution of the scout abdomen radiograph in common pediatric fluoroscopic procedures

BACKGROUND

Contrast enema, voiding cystourethrography and upper gastrointestinal studies are the most common fluoroscopic procedures in children. Scout abdomen radiographs have been routinely obtained prior to fluoroscopy and add to the radiation exposure from these procedures. Elimination of unnecessary routine scout radiographs in select studies might significantly reduce radiation exposure to children and improve the overall benefit-to-risk ratio of these fluoroscopic procedures.

OBJECTIVE

To determine the radiation exposure contribution of the preliminary/scout abdomen radiographs with respect to the radiation exposure of the total procedure.

MATERIALS AND METHODS

We retrospectively collected demographic information and radiation exposure values of dose area product (in Gy-cm(2)) and entrance air kerma (in mGy) - initially for the scout abdomen radiographs done prior to fluoroscopy and subsequently the total procedural radiation values (the combined values of the scout radiograph and fluoroscopic radiation exposure) - in children who underwent contrast enemas, voiding cystourethrograms and upper gastrointestinal studies in a 4-month period. The radiation parameters, including fluoroscopy time, dose area product and entrance air kerma, were available in the log book maintained in the fluoroscopy suite. Fluoroscopy procedures were performed on a single fluoroscopy machine using four frames per second pulse rate and other radiation-minimizing techniques. Usage of the grid to obtain scout radiographs was also recorded. The proportion of radiation exposure from the scout radiograph relative to that of the total procedure was calculated by dividing the individual parameters of the scout to the total procedural values and multiplied by 100 to express these values as a percentage. We calculated mean, median and range and performed statistical analysis of the data.

RESULTS

A total of 151 procedures performed on 71 males and 80 females qualified for the study. The age range of the patients was 2 days to 18 years, with a mean of nearly 3.5 years (40 months) and median of 15 months. There were 63 upper gastrointestinal studies, 65 voiding cystourethrography studies and 23 contrast enema studies. The fluoroscopy time for all procedures combined ranged from 0.1 min (6 s) to 2 min, with mean and median values of 0.4 min and 0.3 min, respectively. The fractional radiation exposure contribution for the dose area product of scout abdomen radiograph to the total procedure ranged from 4% to 98%, with mean and median values of 51% and 49%, respectively. The fractional contribution of the scout radiograph to the total procedure for the entrance air kerma values ranged from 6% to 97%, with mean and median values of 29% and 26%, respectively. There was a significant negative correlation (P<0.001) between fluoroscopy radiation time and the proportion of radiation parameters of scout radiograph to total procedural values.

CONCLUSION

Scout radiographs can contribute a significant proportion (median values of approximately 50% for the dose area product and 26% for the entrance air kerma) of radiation exposure in common fluoroscopy procedures in children.

Validity of the size-specific dose estimate in adults undergoing coronary CT angiography: comparison with the volume CT dose index

Size-specific dose estimate (SSDE) takes into account the patient size but remains to be fully validated for adult coronary computed tomography angiography (CCTA). We investigated the appropriateness of SSDE for accurate estimation of patient dose by comparing the SSDE and the volume CT dose index (CTDIvol) in adult CCTA. This prospective study received institutional review board approval, and informed consent was obtained from each patient. We enrolled 37 adults who underwent CCTA with a 320-row CT. High-sensitivity metal oxide semiconductor field effect transistor dosimeters were placed on the anterior chest. CTDIvol reported by the scanner based on a 32-cm phantom was recorded. We measured chest diameter to convert CTDIvol to SSDE. Using linear regression, we then correlated SSDE with the mean measured skin dose. We also performed linear regression analyses between the skin dose/CTDIvol and the body mass index (BMI), and the skin dose/SSDE and BMI. There was a strong linear correlation (r = 0.93, P < 0.001) between SSDE (mean 37 ± 22 mGy) and mean skin dose (mean 17.7 ± 10 mGy). There was a moderate negative correlation between the skin dose/CTDIvol and BMI (r = 0.45, P < 0.01). The skin dose/SSDE was not affected by BMI (r = 0.06, P > 0.76). SSDE yields a more accurate estimation of the radiation dose without estimation errors attributable to the body size of adult patients undergoing CCTA.

Long-term burden of care and radiation exposure in survivors of esophageal atresia

BACKGROUND

Patients with esophageal atresia with or without tracheoesophageal fistula (EA/TEF) historically have had a high risk of neonatal mortality but the majority of patients are now expected to live into adulthood. However, the long-term burden of care among recent EA/TEF survivors has not been documented.

METHODS

A single-institution retrospective review of newborns with EA/TEF treated from 2001-2005 was conducted, including initial and total hospitalization length of stay, and number of clinic visits and procedures requiring general anesthesia in the first three years of life. Exposure to and number of radiological studies involving ionizing radiation (IR) were recorded.

RESULTS

Seventy-one of 78 (91%) patients survived to discharge and 69 were included for analysis. Mean length of initial hospital stay was 51.3 (range 9-390) days. By age 3 years, patients required 4.5 (mean, range 1-23) procedures performed under general anesthesia, attended 13.5 (mean, range 3-40) outpatient visits and were exposed to 17.4 mSv (mean, range 3.0-59.9) of IR from 40 (mean, range 5-165) radiological studies.

CONCLUSION

Patients with EA/TEF need complex and frequent hospital-based care from infancy to early childhood. Opportunities to critically review clinical services and imaging needs should be explored to improve the experience of patients and their families.

Validation of a MOSFET dosemeter system for determining the absorbed and effective radiation doses in diagnostic radiology

This study aimed to validate a MOSFET dosemeter system for determining absorbed and effective doses (EDs) in the dose and energy range used in diagnostic radiology. Energy dependence, dose linearity and repeatability of the dosemeter were examined. The absorbed doses (ADs) were compared at anterior-posterior projection and the EDs were determined at posterior-anterior, anterior-posterior and lateral projections of thoracic imaging using an anthropomorphic phantom. The radiation exposures were made using digital radiography systems. This study revealed that the MOSFET system with high sensitivity bias supply set-up is sufficiently accurate for AD and ED determination. The dosemeter is recommended to be calibrated for energies <60 and >80 kVp. The entrance skin dose level should be at least 5 mGy to minimise the deviation of the individual dosemeter dose. For ED determination, dosemeters should be implanted perpendicular to the surface of the phantom to prevent the angular dependence error.

Incidence of clinically silent malrotation detected on barium swallow examination in children

INTRODUCTION

Duodenojejunal flexure (DJF) orientation is often examined routinely during contrast swallow studies, including those performed for purely oesophageal queries. We examine the radiation burden and the incidence of malrotation in patients undergoing contrast swallow, without clinical suspicion for malrotation.

METHODS

Two hundred eighteen consecutive contrast swallow studies were reviewed. Patients whose history may potentially suggest malrotation were identified (n = 90), and remaining children were grouped based on whether DJF was examined (Group 1; n = 88) or not (Group 2; n = 40). Data extracted include demographics, radiographic parameters (dosage, screening time, number of images obtained) and examination findings. Outcome measures comprised: (i) prevalence of clinically incidental malrotation; and (ii) influence of additional evaluation of DJF on patient dosage (mean ± SEM).

RESULTS

Malrotation was identified in 2 of 90 patients (2.2%) examined with clinical indications for possible malrotation, but none in Group 1 (13% already had normal DJF confirmed on previous examinations). Groups 1 and 2 were comparable with respect to age and gender (P = ns). Additional evaluation of DJF (Group 1) meant that 54% more images were acquired (48.5 ± 2.9 vs. 31.4 ± 3.4 images in group 2; P = 0.0002) and 24.9% increased screening time (130.8 ± 9.3 vs. 104.7 ± 13.0 seconds in group 2; P = 0.089), resulting in 32.6% increased patient dosage (1.36 ± 0.21 vs. 1.02 ± 0.16 microGym(2) /kg in group 2; P = 0.19).

CONCLUSIONS

This study highlights the increased radiation exposures involved with routine screening for DJF position in those patients without clinical suspicion of malrotation, and raises questions about the validity of this practice; however, further research is needed.