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Spina bifida and myelomeningocele in a 1-day-old newborn. Presurgical CT images were acquired at 80 kVp (CTDI vol , 0.5 mGy) and reconstructed with SAFIRE. (a) Volume-rendered image clearly shows the abnormality of the spine. (b) Coronal CT image clearly shows the myelomeningocele.
Source publication
Given the growing awareness of and concern for potential carcinogenic effects of exposure of children to ionizing radiation at CT, optimizing acquisition parameters is crucial to achieve diagnostically acceptable image quality at the lowest possible radiation dose. Among currently available dose reduction techniques, recent technical innovations ha...
Citations
... There were 58 males and 11 females in the paragonimiasis group, with a median age of 9 (7-13) years, and there were 51 males and 30 females in the tuberculosis group, with a median age of 12 (9)(10)(11)(12)(13) years. The proportion of male patients in the paragonimiasis group (84.1%) was significantly higher than in the tuberculosis group (63.0%), and the median age was significantly lower than in the tuberculosis group (χ 2 = 8.348, P = 0.004; Z = 2.534, P = 0.011). ...
... With the advancement of medical imaging technology and equipment, the radiation dose of CT equipment has gradually decreased, and CT scans are now commonly used to examine children for chest diseases. However, considering that CT is the largest medical source of radiation exposure [12], and results from large-scale epidemiologic studies predicted an increased risk of cancer associated with exposure to CT radiation among radiosensitive children and adolescents [13]. Low-dose CT protocol has been confirmed by a large number of studies, which can significantly reduce ionizing radiation on the premise of ensuring image quality [12,14]. ...
... However, considering that CT is the largest medical source of radiation exposure [12], and results from large-scale epidemiologic studies predicted an increased risk of cancer associated with exposure to CT radiation among radiosensitive children and adolescents [13]. Low-dose CT protocol has been confirmed by a large number of studies, which can significantly reduce ionizing radiation on the premise of ensuring image quality [12,14]. For most cases in our study, lowdose CT protocol was used to evaluated the lesions to perform radioprotection in children. ...
Objective
In this study, we examined the value of chest CT signs combined with peripheral blood eosinophil percentage in differentiating between pulmonary paragonimiasis and tuberculous pleurisy in children.
Methods
Patients with pulmonary paragonimiasis and tuberculous pleurisy were retrospectively enrolled from January 2019 to April 2023 at the Kunming Third People’s Hospital and Lincang People’s Hospital. There were 69 patients with pulmonary paragonimiasis (paragonimiasis group) and 89 patients with tuberculous pleurisy (tuberculosis group). Clinical symptoms, chest CT imaging findings, and laboratory test results were analyzed. Using binary logistic regression, an imaging model of CT signs and a combined model of CT signs and eosinophils were developed to calculate and compare the differential diagnostic performance of the two models.
Results
CT signs were used to establish the imaging model, and the receiver operating characteristic (ROC) curve was plotted. The area under the curve (AUC) was 0.856 (95% CI: 0.799–0.913), the sensitivity was 66.7%, and the specificity was 88.9%. The combined model was established using the CT signs and eosinophil percentage, and the ROC was plotted. The AUC curve was 0.950 (95% CI: 0.919–0.980), the sensitivity was 89.9%, and the specificity was 90.1%. The differential diagnostic efficiency of the combined model was higher than that of the imaging model, and the difference in AUC was statistically significant.
Conclusion
The combined model has a higher differential diagnosis efficiency than the imaging model in the differentiation of pulmonary paragonimiasis and tuberculous pleurisy in children. The presence of a tunnel sign on chest CT, the absence of pulmonary nodules, and an elevated percentage of peripheral blood eosinophils are indicative of pulmonary paragonimiasis in children.
... The high voltage gives a higher dose value in smaller-size patients (Boone, 2007;McCollough et al., 2011). Therefore, we recommend using a lower tube voltage for pediatric patients and a higher one for larger and obese patients (Nagayama et al., 2018). Hence, medical personnel must consider appropriate settings so that the CT number yielded remains feasible for diagnosis with the lowest possible dose. ...
This study aims to develop a software for measuring the computed tomography (CT) number of multiple materials automatically and investigate the impact of tube voltage on the measured CT numbers. The software was specifically design to automatically measure CT number of multiple materials on images of an ACR 464 CT phantom (Gammex, Inc.). Automatic measurements were performed using the matching technique based on the centroids of the phantom and bone objects. The software was tested first on images of the phantom scanned using a GE Revolution EVO 128-slice with rotation variations from 1° to 10° to evaluate its accuracy against rotation. The software was then implemented on images of the phantom scanned with tube voltage variations of 80, 100, 120, and 140 kV. Results of automatic measurements were compared with manual measurements. Manual measurements were performed using a MicroDicom Viewer (MicroDicom Ltd, Sofia, Bulgaria). The results of the two methods were analysed using a paired t-test. The developed software is able to accurately measure the CT number of multiple materials from images reconstructed with variations of rotation and tube voltage. The results of automatic method are not significantly different from the results of manual measurements with a p-value of > 0.05. This study indicated that there is a dependency between the CT number values and the tube voltage. Thus, it is recommended in the quality control (QC) program to measure the CT number of multiple materials using all tube voltages available on the CT machine.
... For CT angiography, low tube voltage imaging is an established approach to increase contrast due to the photoelectric effect [10]. Notably, some studies suggest a similar advantage at low tube voltages in non-contrast examinations [11]. While the relationship between radiation dose and tube current is known to be linear, i.e., doubling the tube current results in doubling the dose, the relationship between dose and tube voltage is proportional to the square of the voltage. ...
Purpose
Unenhanced abdominal CT constitutes the diagnostic standard of care in suspected urolithiasis. Aiming to identify potential for radiation dose reduction in this frequent imaging task, this experimental study compares the effect of spectral shaping and tube voltage modulation on image quality.
Methods
Using a third-generation dual-source CT, eight cadaveric specimens were scanned with varying tube voltage settings with and without tin filter application (Sn 150, Sn 100, 120, 100, and 80 kVp) at three dose levels (3 mGy: standard; 1 mGy: low; 0.5 mGy: ultralow). Image quality was assessed quantitatively by calculation of signal-to-noise ratios (SNR) for various tissues (spleen, kidney, trabecular bone, fat) and subjectively by three independent radiologists based on a seven-point rating scale (7 = excellent; 1 = very poor).
Results
Irrespective of dose level, Sn 100 kVp resulted in the highest SNR of all tube voltage settings. In direct comparison to Sn 150 kVp, superior SNR was ascertained for spleen (p ≤ 0.004) and kidney tissue (p ≤ 0.009). In ultralow-dose scans, subjective image quality of Sn 100 kVp (median score 3; interquartile range 3–3) was higher compared with conventional imaging at 120 kVp (2; 2–2), 100 kVp (1; 1–2), and 80 kVp (1; 1–1) (all p < 0.001). Indicated by an intraclass correlation coefficient of 0.945 (95% confidence interval: 0.927–0.960), interrater reliability was excellent.
Conclusions
In abdominal CT with maximised dose reduction, tin prefiltration at 100 kVp allows for superior image quality over Sn 150 kVp and conventional imaging without spectral shaping.
... Prior to the development of multidetector computed tomography (CT), paediatric chest imaging was difficult to perform on children with congenital heart disease. With the recent developments in CT equipment, the technical performance of CT has improved dramatically over the past two decades [1][2][3]. Significant improvements in temporal resolution, including shorter rotation times [4,5], a high helical pitch [6,7], and wide detectors [8,9], have proven effective in reducing artefacts associated with high heart rates and motion. These advancements have substantially improved the diagnostic capabilities of congenital heart diseases in children [10]. ...
Background
Adaptive collimation reduces the dose deposited outside the imaged volume along the z-axis. An increase in the dose deposited outside the imaged volume (to the lens and thyroid) in the z-axis direction is a concern in paediatric computed tomography (CT).
Objective
To compare the dose deposited outside the imaged volume (to the lens and thyroid) between 40-mm and 80-mm collimation during thoracic paediatric helical CT.
Materials and methods
We used anthropomorphic phantoms of newborns and 5-year-olds with 40-mm and 80-mm collimation during helical CT. We compared the measured dose deposited outside the imaged volume using optically stimulated luminescence dosimeters (OSLD) at the surfaces of the lens and thyroid and the image noise between the 40-mm and 80-mm collimations.
Results
There were significant differences in the dose deposited outside the imaged volume (to the lens and thyroid) between the 40-mm and 80-mm collimations for both phantoms (P < 0.01).
Conclusion
Compared with that observed for 80-mm collimation in helical CT scans of the paediatric thorax, the dose deposited outside the imaged volume (to the lens and thyroid) was significantly lower in newborns and 5-year-olds with 40-mm collimation.
... The CT parameters used were; tube voltage of 130 kV, 80 mA tube current, and 5 mm slice thickness. In children, the ALARA (As Low As Reasonably Achievable) principle was followed, aiming to minimize radiation exposure to the lowest level necessary for accurate diagnosis (tube voltage of 80 kV, 20 mA tube current) [13]. The entire SPECT/ CT acquisition took about 20-25 min. ...
Background
The best way to assess renal cortical scarring is planar scintigraphy with 99m Tc-dimercaptosuccinic acid (DMSA), while the value of single-photon emission computed tomography/computed tomography (SPECT/CT) is not well validated. The aim of the present study was to assess the value of planar, SPECT, and SPECT/CT scanning using 99m Tc-DMSA in detecting renal cortical scarring.
Methods
Patients with clinically suspected renal cortical scar were included in this prospective cohort. 99m Tc-DMSA Planar images were obtained approximately 3–4 h after intravenous injection (IV) of 185 MBq of the tracer. SPECT/CT scans were obtained immediately after the planar ones. An expert nuclear medicine doctor who was unaware of the patient's clinical history or any previous imaging results analyzed the images. Each kidney was given a score of 0 for no obvious defects, 1 for equivocal lesions, 2 for a single defect, 3 for several defects, and 4 for non-visualized/non-functioning kidney (in CT images). The results of each method were then compared to each other.
Results
One hundred eighty-six kidneys from ninety-three individuals were eligible for assessment. Planar scans detected 21 kidneys with equivocal lesions, 5 with single and 7 with multiple defects. SPECT scans detected 17 kidneys with single and 40 with multiple defects, while SPECT/CT scans revealed 5 with single and 11 with multiple defects. Only 5 of the 17 kidneys with single defects diagnosed by SPECT imaging had a scar in the SPECT/CT scans, whereas the remaining 12 had a solitary cortical cyst in the CT images. Only 11 of 40 kidneys with multiple defects on SPECT were shown to have a scar in the corresponding SPECT/CT images, whereas the rest matched to either hydro-nephrotic changes or multiple cortical cysts. Four kidneys with multiple defects on the SPECT/CT images were normal in the planar readings, were ascribed to an increase in renal background activity and a reduction in renal function.
Conclusions
In cases with suspected renal cortical scar, 99m Tc-DMSA SPECT/CT scanning outperformed both planar and SPECT imaging by reducing the number of false-positive SPECT readings and false-negative planar readings.
... While existing literature often focuses on singular aspects of these advancements to lower irradiation in pediatric populations, such as deep learning, photon counting, or specific iterative reconstruction techniques, there is a noticeable gap in comprehensively covering all these areas together [5,7,11]. This narrative review aims to bridge the gap in existing literature by providing an all-encompassing exploration of multifaceted advancements in pediatric CT imaging technologies. ...
In pediatric radiology, balancing diagnostic accuracy with reduced radiation exposure is paramount due to the heightened vulnerability of younger patients to radiation. Technological advancements in computed tomography (CT) reconstruction techniques, especially model-based iterative reconstruction and deep learning image reconstruction, have enabled significant reductions in radiation doses without compromising image quality. Deep learning image reconstruction, powered by deep learning algorithms, has demonstrated superiority over traditional techniques like filtered back projection, providing enhanced image quality, especially in pediatric head and cardiac CT scans. Photon-counting detector CT has emerged as another groundbreaking technology, allowing for high-resolution images while substantially reducing radiation doses, proving highly beneficial for pediatric patients requiring frequent imaging. Furthermore, cloud-based dose tracking software focuses on monitoring radiation exposure, ensuring adherence to safety standards. However, the deployment of these technologies presents challenges, including the need for large datasets, computational demands, and potential data privacy issues. This article provides a comprehensive exploration of these technological advancements, their clinical implications, and the ongoing efforts to enhance pediatric radiology’s safety and effectiveness.
Graphical Abstract
... Despite the CT imaging only contributes 11% to the total ionizing radiation exposure, the overall radiation dose exceeds two-thirds of the total dose received [7]. Therefore CT examination needs to be monitored since high-dose exposure poses a risk of inducing cancer in patients, especially in pediatric patients [8][9]. The cells in pediatric patients are actively proliferating, therefore a slight radiation exposure has the potential to disrupt cell growth in children [10]. ...
This study aims to investigate the correlation between abdominal diameter against the their ages in pediatric Computed Tomography (CT) examination. The retrospective images from 96 patients ranging from 0–16 years scanned by the Siemens Somatom Go Top 128 Multi-slice CT scanner were evaluated. In a total of 46 patients were scanned by tube current modulation (TCM) approach and the remaining 50 patients were examined whitout TCM. The effective diameter (Deff) for every patient was automatically calculated using IndoseCT. The evaluation of the size and age correlation was carried out using a regression approach from AAPM Task Group 204. In addition, size-specific dose estimate (SSDE) was also calculated using IndoseCT. The results shows that the patient’s diameters increase along the increase of ages (R2 > 0.68) with rapid growth in the ages of 0-1 years. It is also found that the increase in the patient’s diameter leds to the decrease of SSDE in the non-TCM protocol, while the trend in the TCM protocol is different. The SSDE had a tendency to increase along with the increase in patient sizes (R2 < 0.40).
... Dose optimization in pediatric CT imaging can be achieved by lowering the parameters such as tube voltage (kV) and tube current exposure time product (mAs) specific to the age and weight of the patient [6]. The major limitation of reducing the tube voltage and tube current exposure time product is a relative increase in image noise caused by reduced photon flux which is common when the images are reconstructed with conventional filtered back projection (FBP) [7][8][9][10]. This shortcoming of FBP had led to the evolution of the iterative reconstruction (IR) technique. ...
Purpose
Pediatric computed tomography (CT) head examination has also increased in recent years with the advancement in CT technology; however, children exposed to radiation at the youngest age are more vulnerable to the risks of radiation. The aim of the study is to evaluate radiation dose and image quality of low dose pediatric CT head protocol compared to standard dose pediatric CT head protocol.
Methods
This was a prospective study. Group 1 included 73 patients aged < 1 year and 70 patients in the 1–5 years age group and had undergone CT head examination using the standard dose protocol. Group 2 included 31 patients aged < 1 year and 40 patients in the 1–5 years age group and had undergone CT head examination using the low dose protocol. The radiation dose was measured and image quality was assessed quantitatively and qualitatively.
Results
There was a significant difference in radiation dose between the standard and low dose protocols (p > 0.05) with lower radiation dose for low dose group. The qualitative analysis did not show a significant difference between the standard and low dose protocols. The gray-white matter differentiation (GWMD), attenuation, contrast to noise ratio (CNR) and figure of merit (FOM) were higher in the low dose protocol compared to the standard dose with a significant difference (p > 0.05).
Conclusion
The study concludes that a low dose protocol at 80 kV tube voltage/150 mAs tube current exposure time product/iterative reconstruction-iDose⁴ (level 3) for < 1 year age group and 100 kV/200m As/iDose⁴ (level 3) for 1–5 years age group provides ultra-low effective dose with diagnostically acceptable image quality for pediatric CT head examination compared with standard dose protocol.
... The optimisation process must be performed, however in consultation with radiologists. Studies conducted in other countries have shown that patient dose can be reduced while maintaining diagnostic confidence if the CT parameters are adjusted to patient size (20)(21)(22) . Therefore, it is necessary to raise the awareness of radiographers and radiologists about the adjustment of CT parameters to achieve optimised procedures. ...
The aim of this study was to evaluate optimisation status during common computed tomography (CT) procedures by determining values of volume computed tomography dose index (CTDIvol) and dose-length product (DLP) per examination. Patient and exposure data were collected from the CT console during various CT procedures. The results show that variations in CTDIvol and DLP values were mainly because of differences in the techniques used. The 75th percentile values were set as the third quartile of the median CTDIvol or DLP values for all hospitals. These values of 40.9, 9.0, 9.4 and 16.2 mGy for CTDIvol were determined for head, high-resolution chest, abdomen–pelvis and lumbar spine, respectively. The corresponding DLP values for the same sequence of CT procedures were 900, 360, 487 and 721 mGy.cm, respectively. The updated results provide a basis for optimising the procedures of CT in this country.
... In general, radiation dose is proportional to the square of tube voltage; therefore, a small reduction in tube voltage would result in a significant dose reduction. Theoretically, reducing tube voltage from 120 kVp to 100 kVp or 80 kVp would reduce the radiation dose by 33% and 65%, respectively, assuming all other parameters stay the same [12]. For small-sized patients, as less energy is required for x-ray photon penetration, a relatively low tube voltage is enough to provide sufficient penetration; hence, reducing the radiation dose while preserving image quality [12] is possible. ...
... Theoretically, reducing tube voltage from 120 kVp to 100 kVp or 80 kVp would reduce the radiation dose by 33% and 65%, respectively, assuming all other parameters stay the same [12]. For small-sized patients, as less energy is required for x-ray photon penetration, a relatively low tube voltage is enough to provide sufficient penetration; hence, reducing the radiation dose while preserving image quality [12] is possible. As a result, taking patient's body size into account, an individualized scanning plan based on body mass index (BMI), lateral diameter or body circumference is useful in routine clinical practice [13,14]. ...
... As tube voltage has an exponential relationship with radiation dose, lowering tube voltage is a more effective way to achieve the purpose of dose reduction. The tube voltage is also an indicator of radiation penetration ability, so lowering the tube voltage will increase image noise [12]. Thus, when optimizing radiation dose, it is particularly critical to select the appropriate tube voltage in order to balance image noise and ensure image quality. ...
Background: CT-guided hook-wire localization is an essential step in the management of small pulmonary nodules. Few studies, however, have focused on reducing radiation exposure during the procedure. Purpose: This study aims to explore the feasibility of implementing a low-dose computed tomography (CT)-guided hook wire localization using tailored kVp based on patients’ body size. Materials and Methods: A total of 151 patients with small pulmonary nodules were prospectively enrolled for CT-guided hook wire localization using individualized low-dose CT (LDCT) vs. standard-dose CT (SDCT) protocols. Radiation dose, image quality, characteristics of target nodules and procedure-related variables were compared. All variables were analyzed using Chi-Square and Student’s t-test. Results: The mean CTDIvol was significantly reduced for LDCT (for BMI ≤ 21 kg/m2, 0.56 ± 0.00 mGy and for BMI > 21 kg/m2, 1.48 ± 0.00 mGy) when compared with SDCT (for BMI ≤ 21 kg/m2, 5.24 ± 0.95 mGy and for BMI > 21 kg/m2, 6.69 ± 1.47 mGy). Accordingly, the DLP of LDCT was significantly reduced as compared with that of SDCT (for BMI ≤ 21 kg/m2, 56.86 ± 4.73 vs. 533.58 ± 122.06 mGy.cm, and for BMI > 21 kg/m2, 167.02 ± 38.76 vs. 746.01 ± 230.91 mGy.cm). In comparison with SDCT, the effective dose (ED) of LDCT decreased by an average of 89.42% (for BMI ≤ 21 kg/m2) and 77.68% (for BMI > 21 kg/m2), respectively. Although the images acquired with the LDCT protocol yielded inferior quality to those acquired with the SDCT protocol, they were clinically acceptable for hook wire localization. Conclusions: LDCT-guided localization can provide safety and nodule detection performance comparable to SDCT-guided localization, benefiting radiation dose reduction dramatically, especially for patients with small body mass indexes.
