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Vogiatzi T, Menz R, Verna C, Bornstein MM, Dagassan-Berndt D. Effect of field of view (FOV) positioning and shielding on radiation dose in paediatric CBCT. Dentomaxillofac Radiol 2022; 51:20210316. [PMID: 35762346 PMCID: PMC10043625 DOI: 10.1259/dmfr.20210316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 05/31/2022] [Accepted: 05/31/2022] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To investigate the effect of two different large field of view (FOV) positions in the vertical dimension and shielding (thyroid collar and eyeglasses) on the effective dose and the local doses of various sites of the craniofacial complex. METHODS Organ doses and effective doses were calculated based on the measured doses using 27 pairs of thermoluminescent dosemeters in a paediatric tissue-equivalent of a 10-year-old anthropomorphic phantom. The large FOV of the 3D Accuitomo F170 CBCT scanner was used to image parts of the craniofacial complex. Six protocols were performed: (A) cranial position without shielding; (B) cranial position with shielding; (C) caudal position without shielding; (D) caudal position with shielding, (E) similar to C with 3600 rotation and (F) similar to D with 360° rotation. Measurements were obtained in duplicate, and the relative δ value (%) was applied to compare the average doses between the protocols. RESULTS Changing the FOV position from cranial to caudal without using shielding resulted in an increase of the effective dose of 18.8%. Use of shielding in the caudal position reduced the dose by 31.6%. Local absorbed dose of the thyroid had the most relevant impact on calculation of the effective dose, followed by oesophagus, bone marrow and bone surfaces, especially when comparing the different protocols. CONCLUSIONS Application of shielding devices for thyroid in combination with a most caudal positioning of FOV led to the lowest local absorbed doses as well as the effective dose in a child phantom model.
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Affiliation(s)
- Theodosia Vogiatzi
- Department of Oral Health and Medicine, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Roman Menz
- Division of Radiological Physics, Department of Radiology, University of Basel, Basel, Switzerland
| | - Carlalberta Verna
- Department of Paediatric Oral Health and Orthodontics, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Michael M. Bornstein
- Department of Oral Health and Medicine, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Dorothea Dagassan-Berndt
- Center for Dental Imaging, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
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Fleury AS, Durand RE, Cahill AM, Zhu X, Meyers KE, Otero HJ. Validation of computed tomography angiography as a complementary test in the assessment of renal artery stenosis: a comparison with digital subtraction angiography. Pediatr Radiol 2021; 51:2507-2520. [PMID: 34374838 DOI: 10.1007/s00247-021-05145-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 05/27/2021] [Accepted: 06/28/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND Renal artery stenosis is an important cause of hypertension in children, accounting for 5-10% of cases. When suspected, noninvasive imaging options include ultrasound (US), computed tomography (CT) angiography and magnetic resonance (MR) angiography. However, digital subtraction angiography (DSA) remains the gold standard. OBJECTIVE To investigate the accuracy and inter-reader reliability of CT angiography in children with suspected renal artery stenosis. MATERIALS AND METHODS This is a retrospective study of patients suspected of having renal artery stenosis evaluated by both CT angiography and DSA between 2008 and 2019 at a tertiary pediatric hospital. Only children who underwent CT angiography within 6 months before DSA were included. CT angiography studies were individually reviewed by two pediatric radiologists, blinded to clinical data, other studies and each other's evaluation, to determine the presence of stenosis at the main renal artery and 2nd- and 3rd-order branches. The sensitivity, specificity and accuracy were calculated using DSA as the reference. The effective radiation dose for CT angiography and DSA was also calculated. Kappa statistics were used to assess inter-reader agreement. RESULTS Seventy-four renal units were evaluated (18 girls, 19 boys). The patients' median age was 8 years (range: 1-21 years). Overall, CT angiography was effective in detecting renal artery stenosis with a sensitivity of 85.7%, specificity of 91.5% and accuracy of 88.9%. There was moderate inter-reader agreement at the main renal artery level (k=0.73) and almost perfect inter-reader agreement at the 2nd/3rd order (k=0.98). However, the sensitivity at the 2nd- and 3rd-order level was lower (14.3%). CT angiography provided excellent negative predictive value for evaluating renal artery stenosis at the main renal artery level (90.1%) and at the 2nd- or 3rd-order branches (82.7%). The median effective dose of CT angiography studies was 2.2 mSv (range: 0.6-6.3) while the effective dose of DSA was 13.7 mSv. CONCLUSION CT angiography has high sensitivity and specificity at the main renal artery level with a lower radiation dose than previously assumed. Therefore, it can be used as a diagnostic tool in patients with low to medium risk of renal artery stenosis, and as a screening and treatment planning tool in patients at high risk.
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Affiliation(s)
- Anilawan S Fleury
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Rachelle E Durand
- Department of Radiology and Biomedical Imaging, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Anne Marie Cahill
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Xiaowei Zhu
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA
| | - Kevin E Meyers
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Hansel J Otero
- Department of Radiology, Children's Hospital of Philadelphia, 3401 Civic Center Blvd., Philadelphia, PA, 19104, USA.
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Palas A, Raval J, Aiyer RG, Arunlal B. Pediatric E.N.T. emergencies during COVID-19 pandemic: our experience. Indian J Otolaryngol Head Neck Surg 2021; 74:2809-2813. [PMID: 33425696 PMCID: PMC7781556 DOI: 10.1007/s12070-020-02357-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/23/2020] [Indexed: 01/06/2023] Open
Abstract
Our aim is to analyze effect of covid-19 pandemic in management of pediatric emergencies in E.N.T. and to provide recommendations for management of pediatric emergencies in E.N.T. during pandemic. In this retrospective study we included emergency pediatric cases required early intervention during covid-19 pandemic. Pre operative radiological investigation x-ray was done in all aero digestive foreign body patients. Pre operative HRCT neck and chest with virtual bronchoscopy in foreign body inhalation & compromised airway patients was done only in cases where patient’s clinical condition was stable. Similarly RT PCR for covid-19 screening done only in cases where patient’s clinical condition was stable. Adequate personal protective equipment was used during all the procedures. Total 29 Pediatric patients age ranging from 1 day to 13 years underwent procedures due to history of foreign body inhalation; ingestion, insertion and compromised airway in form of immediate endotracheal intubation were included. Comprehensively we recommend intervention only in emergency procedures during pandemic, use of personal protective equipment during all procedures, preoperative investigations for diagnosis and modifications in operation theatre, anesthesia and surgical techniques to reduce aerosols generation will minimize risk of infection transmission to health care workers.
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Affiliation(s)
- Anand Palas
- Department of E.N.T. and Head-Neck Surgery, Baroda Medical College and S.S.G. Hospital, Vadodara, Gujarat India
| | - Jayman Raval
- Department of E.N.T. and Head-Neck Surgery, Baroda Medical College and S.S.G. Hospital, Vadodara, Gujarat India
| | - R. G. Aiyer
- Department of E.N.T. and Head-Neck Surgery, Baroda Medical College and S.S.G. Hospital, Vadodara, Gujarat India
| | - Bhagyalakshmi Arunlal
- Department of E.N.T. and Head-Neck Surgery, Baroda Medical College and S.S.G. Hospital, Vadodara, Gujarat India
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C A, K A, H S, Z A, W S B, T F, G D. Noise Reduction in CT Images Using a Selective Mean Filter. JOURNAL OF BIOMEDICAL PHYSICS AND ENGINEERING 2020; 10:623-634. [PMID: 33134222 PMCID: PMC7557470 DOI: 10.31661/jbpe.v0i0.2002-1072] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/07/2020] [Indexed: 11/16/2022]
Abstract
Background Noise reduction is a method for reducing CT dose; however, it can reduce image quality. Objective This study aims to propose a selective mean filter (SMF) and evaluate its effectiveness for noise suppression in CT images. Material and Methods This experimental study proposed and implemented the new noise reduction algorithm. The proposed algorithm is based on a mean filter (MF), but the calculation of the mean pixel value using the neighboring pixels in a kernel selectively applied a threshold value based on the noise of the image. The SMF method was evaluated using images of phantoms. The dose reduction was estimated by comparing the image noise acquired with a lower dose after implementing the SMF method and the noise in the original image acquired with a higher dose. For comparison, the images were also filtered with an adaptive mean filter (AMF) and a bilateral filter (BF). Results The spatial resolution of the image filtered with the SMF was similar to the original images and the images filtered with the BF. While using the AMF, spatial resolution was significantly corrupted. The noise reduction achieved using the SMF was up to 75%, while it was up to 50% using the BF. Conclusion SMF significantly reduces the noise and preserves the spatial resolution of the image. The noise reduction was more pronounced with BF, and less pronounced with AMF.
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Affiliation(s)
- Anam C
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Jl. Prof. Soedarto SH, Tembalang, Semarang 50275, Central Java, Indonesia
| | - Adi K
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Jl. Prof. Soedarto SH, Tembalang, Semarang 50275, Central Java, Indonesia
| | - Sutanto H
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Jl. Prof. Soedarto SH, Tembalang, Semarang 50275, Central Java, Indonesia
| | - Arifin Z
- MSc, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Jl. Prof. Soedarto SH, Tembalang, Semarang 50275, Central Java, Indonesia
| | - Budi W S
- PhD, Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Jl. Prof. Soedarto SH, Tembalang, Semarang 50275, Central Java, Indonesia
| | - Fujibuchi T
- PhD, Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Dougherty G
- PhD, Department of Applied Physics and Medical Imaging, California State University Channel Islands, Camarillo, CA 93012, USA
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Abstract
OBJECTIVE. Pediatric CT angiography (CTA) presents unique challenges compared with adult CTA. Because of the ionizing radiation exposure, CTA should be used judiciously in children. The pearls offered here are observations gleaned from the authors' experience in the use of pediatric CTA. We also present some potential follies to be avoided. CONCLUSION. Understanding the underlying principles and paying meticulous attention to detail can substantially optimize dose and improve the diagnostic quality of pediatric CTA.
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Zirpoli S, Munari AM, Primolevo A, Scarabello M, Costanzo S, Farolfi A, Lista G, Zoia E, Zuccotti GV, Riccipetitoni G, Righini A. Agreement between magnetic resonance imaging and computed tomography in the postnatal evaluation of congenital lung malformations: a pilot study. Eur Radiol 2019; 29:4544-4554. [PMID: 30796572 DOI: 10.1007/s00330-019-06042-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/20/2018] [Accepted: 01/24/2019] [Indexed: 02/07/2023]
Abstract
OBJECTIVES To compare postnatal magnetic resonance imaging (MRI) with the reference standard computed tomography (CT) in the identification of the key features for diagnosing different types of congenital lung malformation (CLM). METHODS Respiratory-triggered T2-weighted single-shot turbo spin echo (ss-TSE), respiratory-triggered T1-weighted turbo field echo (TFE), balanced fast field echo (BFFE), and T2-weighted MultiVane sequences were performed at 1.5 T on 20 patients prospectively enrolled. Two independent radiologists examined the postnatal CT and MRI evaluating the presence of cysts, hyperinflation, solid component, abnormal arteries and/or venous drainage, and bronchocele. Diagnostic performance of MRI was calculated and the agreement between the findings was assessed using the McNemar-Bowker test. Interobserver agreement was measured with the kappa coefficient. RESULTS CT reported five congenital pulmonary airway malformations (CPAMs), eight segmental bronchial atresias, five bronchopulmonary sequestrations (BPS), one congenital lobar overinflation, one bronchogenic cyst, and three hybrid lesions. MRI reported the correct diagnosis in 19/20 (95%) patients and the malformation was correctly classified in 22/23 cases (96%). MRI correctly identified all the key findings described on the CT except for the abnormal vascularization (85.7% sensitivity, 100% specificity, 100% PPV, 94.1% NPV, 95% accuracy for arterial vessels; 57.1% sensitivity, 100% specificity, 100% PPV, 84.2% NPV, 87% accuracy for venous drainage). CONCLUSIONS MRI can represent an effective alternative to CT in the postnatal assessment of CLM. In order to further narrow the gap with CT, the use of contrast material and improvements in sequence design are needed to obtain detailed information on vascularization, which is essential for surgical planning. KEY POINTS • Congenital lung malformations (CLMs) can be effectively studied by MRI avoiding radiation exposure. • Crucial features of CLM have similar appearance when comparing CT with MRI. • MRI performs very well in CLM except for aberrant vessel detection and characterization.
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Affiliation(s)
- Salvatore Zirpoli
- Pediatric Radiology and Neuroradiology, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy.
| | - Alice Marianna Munari
- Pediatric Radiology and Neuroradiology, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | | | - Marco Scarabello
- Postgraduate School in Radiodiagnostics, Università degli Studi di Milano, Via Festa del Perdono 7, 20122, Milan, Italy
| | - Sara Costanzo
- Department of Pediatric Surgery, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | - Andrea Farolfi
- Department of Pediatrics, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | - Gianluca Lista
- Neonatal Intensive Care Unit, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | - Elena Zoia
- Pediatric Intensive Care Unit, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | - Gian Vincenzo Zuccotti
- Department of Pediatrics, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | - Giovanna Riccipetitoni
- Department of Pediatric Surgery, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
| | - Andrea Righini
- Pediatric Radiology and Neuroradiology, ASST Fatebenefratelli-Sacco Milano, Children's Hospital V. Buzzi, Via Castelvetro 32, 20154, Milan, Italy
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Li L, Li H, Shu J, Pan J, Chen X, Ying M, Xu Y, Wang D, Pang P. Influences of scan-position on clinical ultra-high-resolution CT scanning: a preliminary study. Sci Rep 2019; 9:1134. [PMID: 30718553 PMCID: PMC6362237 DOI: 10.1038/s41598-018-37514-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/04/2018] [Indexed: 11/15/2022] Open
Abstract
The aim of this study is to access influences of scan-position on clinical ultra-high-resolution CT scanning. We proposed a breath-hold assisted ultra-high-resolution scanning technology (scan scheme G) and compared with scan scheme A (regular CT plain scan) and scheme B (1024 ultra-high-resolution scan with patients stay in supine position). A total of 30 patients with fGGO were included in this study. Three highly experienced chest imaging doctors were employed to score the image and to select regions of interest (ROIs) for CT value and signal-to-noise ratio (SNR) calculation. In comparison with scan A and B, this new scan scheme G shows more clear CT images and higher SNRs at overall lung field (the p-values of A versus G and B versus G are 0.041 and 0.065, respectively). These findings suggest that scan-G provides a better image quality and contributes significantly to clinical detection accuracy of fGGO.
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Affiliation(s)
- Lu Li
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China
| | - HuiMin Li
- Department of Radiology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, 200092, China
| | - JinEr Shu
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China.
| | - JiangFeng Pan
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China
| | - XiaoRong Chen
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China
| | - MingLiang Ying
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China
| | - YiBin Xu
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China
| | - Dingjun Wang
- Department of Radiology, Jinhua Central Hospital of Zhejiang University, Jinhua, 321000, China
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Ge G, Zhang J, Winkler M, Lumby C, Cong W, Wang G. Clinical validation of CT image reconstruction with interior tomography. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2018; 26:303-309. [PMID: 29562569 DOI: 10.3233/xst-17329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Active x-ray collimation is well adopted in radiography and fluoroscopy for radiation dose reduction and image quality improvement. The application of this concept in computed tomography (CT) is significantly limited due to the truncation of projection data. Generally, an internal field of view (FOV) inside an imaging object cannot be exactly reconstructed only from the truncated projection data. Recent research shows that given some prior information of the FOV image, interior tomography can provide a unique and stable solution for image reconstruction of an internal FOV. The objective of this study is to evaluate the performance of interior reconstruction based on patient datasets obtained from a clinical CT scanner with dual x-ray tubes, which simultaneously gives full projections and truncated projections. Image reconstructions are performed from full and truncated projection data for the comparison of image quality, respectively. The reconstructed CT images were reviewed by a radiologist and a resident. The evaluation results of two observers showed that CT images reconstructed with truncated projections met clinically diagnostic requirements and were comparable to clinical images. This study demonstrates that with the development of interior tomography, active x-ray collimation in the imaging plane can be readily employed in CT imaging to further reduce patient radiation and improve image quality.
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Affiliation(s)
- Gary Ge
- Department of Radiation Medicine, University of Kentucky, Lexington, KY, USA
| | - Jie Zhang
- Department of Radiology, University of Kentucky, Lexington, KY, USA
| | - Michael Winkler
- Department of Radiology, University of Kentucky, Lexington, KY, USA
| | - Cynthia Lumby
- Department of Radiology, University of Kentucky, Lexington, KY, USA
| | - Wenxiang Cong
- Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Ge Wang
- Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, NY, USA
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Cooper JN, Lodwick DL, Adler B, Lee C, Minneci PC, Deans KJ. Patient characteristics associated with differences in radiation exposure from pediatric abdomen-pelvis CT scans: a quantile regression analysis. Comput Biol Med 2017; 85:7-12. [DOI: 10.1016/j.compbiomed.2017.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/27/2017] [Accepted: 04/11/2017] [Indexed: 10/19/2022]
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Carver DE, Kost SD, Fraser ND, Segars WP, Pickens DR, Price RR, Stabin MG. Realistic phantoms to characterize dosimetry in pediatric CT. Pediatr Radiol 2017; 47:691-700. [PMID: 28283725 PMCID: PMC5420344 DOI: 10.1007/s00247-017-3805-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 12/07/2016] [Accepted: 02/10/2017] [Indexed: 10/24/2022]
Abstract
BACKGROUND The estimation of organ doses and effective doses for children receiving CT examinations is of high interest. Newer, more realistic anthropomorphic body models can provide information on individual organ doses and improved estimates of effective dose. MATERIALS AND METHODS Previously developed body models representing 50th-percentile individuals at reference ages (newborn, 1, 5, 10 and 15 years) were modified to represent 10th, 25th, 75th and 90th height percentiles for both genders and an expanded range of ages (3, 8 and 13 years). We calculated doses for 80 pediatric reference phantoms from simulated chest-abdomen-pelvis exams on a model of a Philips Brilliance 64 CT scanner. Individual organ and effective doses were normalized to dose-length product (DLP) and fit as a function of body diameter. RESULTS We calculated organ and effective doses for 80 reference phantoms and plotted them against body diameter. The data were well fit with an exponential function. We found DLP-normalized organ dose to correlate strongly with body diameter (R2>0.95 for most organs). Similarly, we found a very strong correlation with body diameter for DLP-normalized effective dose (R2>0.99). Our results were compared to other studies and we found average agreement of approximately 10%. CONCLUSION We provide organ and effective doses for a total of 80 reference phantoms representing normal-stature children ranging in age and body size. This information will be valuable in replacing the types of vendor-reported doses available. These data will also permit the recording and tracking of individual patient doses. Moreover, this comprehensive dose database will facilitate patient matching and the ability to predict patient-individualized dose prior to examination.
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Affiliation(s)
- Diana E Carver
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA.
| | - Susan D Kost
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Nicholas D Fraser
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - W Paul Segars
- Carl E. Ravin Advanced Imaging Laboratories, Duke University, Hock Plaza Suite 302, 2424 Erwin Road, Durham, NC, 27705, USA
| | - David R Pickens
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Ronald R Price
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
| | - Michael G Stabin
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1161 21st Avenue South, Nashville, TN, 37232, USA
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Park JE, Choi YH, Cheon JE, Kim WS, Kim IO, Cho HS, Ryu YJ, Kim YJ. Image quality and radiation dose of brain computed tomography in children: effects of decreasing tube voltage from 120 kVp to 80 kVp. Pediatr Radiol 2017; 47:710-717. [PMID: 28293707 DOI: 10.1007/s00247-017-3799-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 01/01/2017] [Accepted: 02/10/2017] [Indexed: 11/27/2022]
Abstract
BACKGROUND Computed tomography (CT) has generated public concern associated with radiation exposure, especially for children. Lowering the tube voltage is one strategy to reduce radiation dose. OBJECTIVE To assess the image quality and radiation dose of non-enhanced brain CT scans acquired at 80 kilo-voltage peak (kVp) compared to those at 120 kVp in children. MATERIALS AND METHODS Thirty children who had undergone both 80- and 120-kVp non-enhanced brain CT were enrolled. For quantitative analysis, the mean attenuation of white and gray matter, attenuation difference, noise, signal-to-noise ratio, contrast-to-noise ratio and posterior fossa artifact index were measured. For qualitative analysis, noise, gray-white matter differentiation, artifact and overall image quality were scored. Radiation doses were evaluated by CT dose index, dose-length product and effective dose. RESULTS The mean attenuations of gray and white matter and contrast-to-noise ratio were significantly increased at 80 kVp, while parameters related to image noise, i.e. noise, signal-to-noise ratio and posterior fossa artifact index were higher at 80 kVp than at 120 kVp. In qualitative analysis, 80-kVp images showed improved gray-white differentiation but more artifacts compared to 120-kVp images. Subjective image noise and overall image quality scores were similar between the two scans. Radiation dose parameters were significantly lower at 80 kVp than at 120 kVp. CONCLUSION In pediatric non-enhanced brain CT scans, a decrease in tube voltage from 120 kVp to 80 kVp resulted in improved gray-white matter contrast, comparable image quality and decreased radiation dose.
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Affiliation(s)
- Ji Eun Park
- Department of Radiology, Graduate School, Kyung Hee University Hospital, Seoul, South Korea
| | - Young Hun Choi
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea.
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea.
| | - Jung-Eun Cheon
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea
| | - Woo Sun Kim
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea
| | - In-One Kim
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
- Department of Radiology, Seoul National University College of Medicine, Seoul, South Korea
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea
| | - Hyun Suk Cho
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
| | - Young Jin Ryu
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
| | - Yu Jin Kim
- Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 110-744, South Korea
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Seifeldein GS, Omar NN, Faddan NHA, Elraheem OA. Low dose multidetector computed tomography in localizing the transition zone of Hirschsprung’s Disease: A novel study. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2016. [DOI: 10.1016/j.ejrnm.2016.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Irodi A, Leena RV, Prabhu SM, Gibikote S. Role of Computed Tomography in Pediatric Chest Conditions. Indian J Pediatr 2016; 83:675-90. [PMID: 26916888 DOI: 10.1007/s12098-015-1955-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 11/04/2015] [Indexed: 12/15/2022]
Abstract
CT is the preferred cross-sectional imaging modality for detailed evaluation of anatomy and pathology of the lung and tracheobronchial tree, and plays a complimentary role in the evaluation of certain chest wall, mediastinal, and cardiac abnormalities. The article provides an overview of indications and different types of CT chest, findings in common clinical conditions, and briefly touches upon the role of each team member in optimizing and thus reducing radiation dose.
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Affiliation(s)
- Aparna Irodi
- Department of Radiology, Christian Medical College, Vellore, 632004, Tamil Nadu, India
| | - R V Leena
- Department of Radiology, Christian Medical College, Vellore, 632004, Tamil Nadu, India
| | - Shailesh M Prabhu
- Department of Radiology, SSM Superspeciality Hospital, Hassan, Karnataka, India
| | - Sridhar Gibikote
- Department of Radiology, Christian Medical College, Vellore, 632004, Tamil Nadu, India.
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14
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Akhlaghi P, Hoseinian-Azghadi E, Miri-Hakimabad H, Rafat-Motavalli L. A Monte Carlo study on quantifying the amount of dose reduction by shielding the superficial organs of an Iranian 11-year-old boy. J Med Phys 2016; 41:246-253. [PMID: 28144117 PMCID: PMC5228048 DOI: 10.4103/0971-6203.195189] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
A method for minimizing organ dose during computed tomography examinations is the use of shielding to protect superficial organs. There are some scientific reports that usage of shielding technique reduces the surface dose to patients with no appreciable loss in diagnostic quality. Therefore, in this Monte Carlo study based on the phantom of a 11-year-old Iranian boy, the effect of using an optimized shield on dose reduction to body organs was quantified. Based on the impact of shield on image quality, lead shields with thicknesses of 0.2 and 0.4 mm were considered for organs exposed directly and indirectly in the scan range, respectively. The results showed that there is 50%–62% reduction in amounts of dose for organs located fully or partly in the scan range at different tube voltages and modeling the true location of all organs in human anatomy, especially the ones located at the border of the scan, range affects the results up to 49%.
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Affiliation(s)
- Parisa Akhlaghi
- Department of Medical Physics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Elie Hoseinian-Azghadi
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hashem Miri-Hakimabad
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Laleh Rafat-Motavalli
- Department of Physics, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran
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15
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Kulkarni A, Hsu HH, Ou P, Kutty S. Computed Tomography in Congenital Heart Disease: Clinical Applications and Technical Considerations. Echocardiography 2015; 33:629-40. [DOI: 10.1111/echo.13147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Aparna Kulkarni
- Division of Pediatric Cardiology; Albert Einstein College of Medicine; Bronx New York
| | - Hao Hua Hsu
- University of Nebraska/Creighton University Joint Division of Pediatric Cardiology; Children's Hospital and Medical Center; Omaha Nebraska
| | - Phalla Ou
- Department of Radiology; Hospital Bichat; University Paris Diderot; APHP; Paris France
| | - Shelby Kutty
- University of Nebraska/Creighton University Joint Division of Pediatric Cardiology; Children's Hospital and Medical Center; Omaha Nebraska
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16
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Kost SD, Fraser ND, Carver DE, Pickens DR, Price RR, Hernanz-Schulman M, Stabin MG. Patient-specific dose calculations for pediatric CT of the chest, abdomen and pelvis. Pediatr Radiol 2015; 45:1771-80. [PMID: 26142256 PMCID: PMC4623993 DOI: 10.1007/s00247-015-3400-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/15/2015] [Accepted: 06/01/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND Organ dose is essential for accurate estimates of patient dose from CT. OBJECTIVE To determine organ doses from a broad range of pediatric patients undergoing diagnostic chest-abdomen-pelvis CT and investigate how these relate to patient size. MATERIALS AND METHODS We used a previously validated Monte Carlo simulation model of a Philips Brilliance 64 multi-detector CT scanner (Philips Healthcare, Best, The Netherlands) to calculate organ doses for 40 pediatric patients (M:F = 21:19; range 0.6-17 years). Organ volumes and positions were determined from the images using standard segmentation techniques. Non-linear regression was performed to determine the relationship between volume CT dose index (CTDIvol)-normalized organ doses and abdominopelvic diameter. We then compared results with values obtained from independent studies. RESULTS We found that CTDIvol-normalized organ dose correlated strongly with exponentially decreasing abdominopelvic diameter (R(2) > 0.8 for most organs). A similar relationship was determined for effective dose when normalized by dose-length product (R(2) = 0.95). Our results agreed with previous studies within 12% using similar scan parameters (e.g., bowtie filter size, beam collimation); however results varied up to 25% when compared to studies using different bowtie filters. CONCLUSION Our study determined that organ doses can be estimated from measurements of patient size, namely body diameter, and CTDIvol prior to CT examination. This information provides an improved method for patient dose estimation.
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Affiliation(s)
- Susan D Kost
- Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA.
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Nicholas D Fraser
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Diana E Carver
- Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - David R Pickens
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ronald R Price
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Marta Hernanz-Schulman
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael G Stabin
- Physics & Astronomy Department, Vanderbilt University, 6301 Stevenson Center, Nashville, TN, 37235, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
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17
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Fowkes LA, Koh DM, Collins DJ, Jerome NP, MacVicar D, Chua SC, Pearson ADJ. Childhood extracranial neoplasms: the role of imaging in drug development and clinical trials. Pediatr Radiol 2015; 45:1600-15. [PMID: 26045035 DOI: 10.1007/s00247-015-3342-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 02/16/2015] [Accepted: 03/16/2015] [Indexed: 12/25/2022]
Abstract
Cancer is the leading cause of death in children older than 1 year of age and new drugs are necessary to improve outcomes. Imaging is crucial to the drug development process and assessment of therapeutic response. In adults, tumours are often assessed with CT using size criteria. Unfortunately, techniques established in adults are not necessarily applicable in children due to differing pathophysiology, ability to cooperate and increased susceptibility to ionising radiation. MRI, in particular quantitative MRI, has to date not been fully utilised in children with extracranial neoplasms. The specific challenges of imaging in children, the potential for functional imaging techniques to inform upon and their inclusion in clinical trials are discussed.
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Affiliation(s)
- Lucy A Fowkes
- Department of Radiology, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK.
| | - Dow-Mu Koh
- Department of Radiology, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
| | - David J Collins
- Cancer Research UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, 15 Cotswold Road, Sutton, SM2 5NG, Surrey, UK
| | - Neil P Jerome
- Cancer Research UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, 15 Cotswold Road, Sutton, SM2 5NG, Surrey, UK
| | - David MacVicar
- Department of Radiology, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
| | - Sue C Chua
- Nuclear Medicine & PET Department, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
| | - Andrew D J Pearson
- Paediatric Drug Development Unit, Children and Young People's Unit, Royal Marsden NHS Foundation Trust, Downs Road, Sutton, SM2 5PT, Surrey, UK
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18
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Sulieman A, Tammam N, Alzimami K, Elnour AM, Babikir E, Alfuraih A. Dose reduction in chest CT examination. RADIATION PROTECTION DOSIMETRY 2015; 165:185-189. [PMID: 25836698 DOI: 10.1093/rpd/ncv123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Computed tomography (CT) examinations involve relatively high doses to patients. The objectives of this study were to optimise the radiation dose for patient during CT chest scan and to estimate the lifetime cancer risk. A total of 50 patients were studied: control group (A) (38 patients) and optimisation group (B) (12 patients). The optimisation protocol was based on CT pitch increment and lowering tube current. The mean volume CT dose index (CTDI vol) was 21.17 mGy and dose length product (DLP) was 839.0 mGy cm for Group A, and CTDI vol was 8.3 mGy and DLP was 339.7 for Group B. The overall cancer risk was estimated to be 8.0 and 3.0 cancer incidence per million for Groups A and B, respectively. The patient dose optimisation during CT chest was investigated. Lowering tube current and pitch increment achieved a radiation dose reduction of up to 60 % without compromising the diagnostic findings.
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Affiliation(s)
- A Sulieman
- Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Alkharj, Kingdom of Saudi Arabia College of Medical Radiologic Science, Sudan University of Science and Technology, Khartoum, Sudan
| | - N Tammam
- College of Medical Radiologic Science, Sudan University of Science and Technology, Khartoum, Sudan
| | - K Alzimami
- Radiological Sciences Department, College of Applied Sciences, King Saud University, Riyadh, Saudi Arabia
| | - A M Elnour
- College of Medical Radiologic Science, Sudan University of Science and Technology, Khartoum, Sudan
| | - E Babikir
- Radiological Sciences Department, College of Applied Sciences, King Saud University, Riyadh, Saudi Arabia
| | - A Alfuraih
- Radiological Sciences Department, College of Applied Sciences, King Saud University, Riyadh, Saudi Arabia
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19
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Ernst CW, Hulstaert TL, Belsack D, Buls N, Van Gompel G, Nieboer KH, Buyl R, Verhelle F, De Maeseneer M, de Mey J. Dedicated sub 0.1 mSv 3DCT using MBIR in children with suspected craniosynostosis: quality assessment. Eur Radiol 2015; 26:892-9. [PMID: 26123408 PMCID: PMC4747997 DOI: 10.1007/s00330-015-3870-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 04/17/2015] [Accepted: 06/01/2015] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To retrospectively compare image quality of a lowered dose CT protocol to a standard CT protocol in children with suspicion of craniosynostosis. METHODS Forty-eight patients (age 0- 35 months), who presented with a cranial deformity underwent cranial 3D CT to assess sutural patency: between 2009 - 2010, 24 patients were imaged with a standard protocol (CTDIvol 32.18 mGy), from 2011-2012, 24 underwent a low dose protocol (0.94 mGy) combined with iterative reconstruction. Image quality was evaluated by both expert reading and objective analysis. Differences were assessed by independent t-test and Mann-Whitney U test, interreader agreement by Cohen's Kappa test. RESULTS Effective dose of the low dose protocol was 0.08 mSv, corresponding to a reduction of 97 %. Image quality was similar in both groups in terms of overall diagnostic acceptability, objective noise measurements, subjective cranial bone edge sharpness and presence of artefacts. For objective sharpness of cranial bone-brain interface and subjective perception of noise, the images of the low dose protocol were superior. For all evaluated structures, interreader agreement was moderate to almost perfect. CONCLUSION In the diagnosis of craniosynostosis in children with cranial deformities, a dedicated sub 0.1 mSv cranial 3DCT protocol can be used without loss in image quality. KEY POINTS 3DCT is used for the diagnosis of craniosynostosis. Imaging protocols should be optimized to minimize radiation exposure to children. Combining 80 kVp with iterative reconstruction can help to reduce dose. A sub 0.1 mSv cranial 3DCT protocol can be used without loss of diagnostic quality.
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Affiliation(s)
- Caroline W Ernst
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium.
| | - Tine L Hulstaert
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Dries Belsack
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Nico Buls
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Gert Van Gompel
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Koenraad H Nieboer
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Ronald Buyl
- Department of Biomedical Statistics and Informatics, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Filip Verhelle
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Michel De Maeseneer
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
| | - Johan de Mey
- Department of Radiology, Universitair Ziekenhuis Brussel, Laarbeeklaan 101, 1090, Brussels, Belgium
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20
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Al Mahrooqi KMS, Ng CKC, Sun Z. Pediatric Computed Tomography Dose Optimization Strategies: A Literature Review. J Med Imaging Radiat Sci 2015; 46:241-249. [PMID: 31052099 DOI: 10.1016/j.jmir.2015.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 02/20/2015] [Accepted: 03/23/2015] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Computed tomography (CT) dose optimization is an important issue in radiography because CT is the largest contributor to medical radiation dose and its use is increasing. However, CT dose optimization for pediatric patients could be more challenging than their adult counterparts. The purpose of this literature review was to identify and discuss the current pediatric CT dose saving techniques. Optimized pediatric protocols were also proposed. METHODS A comprehensive literature search was conducted using the Medline, ProQuest Health and Medical Complete, PubMed, ScienceDirect, Scopus, Springer Link, and Web of Science databases and the keywords CT, pediatric, optimization, protocol, and radiation dose to identify articles focusing on pediatric CT dose optimization strategies published between 2004 and 2014. RESULTS AND SUMMARY Seventy-seven articles were identified in the literature search. Strategies for optimizing a range of scan parameters and technical considerations including tube voltage and current, iterative reconstruction, diagnostic reference levels, bowtie filters, scout view, pitch, scan collimation and time, overscanning, and overbeaming for pediatric patients with different ages and body sizes and compositions were discussed. An example of optimized pediatric protocols specific to age and body size for the 64-slice CT scanners was devised. It is expected that this example could provide medical radiation technologists, radiologists, and medical physicists with ideas to optimize their pediatric protocols.
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Affiliation(s)
| | - Curtise Kin Cheung Ng
- Department of Medical Radiation Sciences, Curtin University, Perth, Western Australia, Australia.
| | - Zhonghua Sun
- Department of Medical Radiation Sciences, Curtin University, Perth, Western Australia, Australia
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21
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Yoon H, Kim MJ, Yoon CS, Choi J, Shin HJ, Kim HG, Lee MJ. Radiation dose and image quality in pediatric chest CT: effects of iterative reconstruction in normal weight and overweight children. Pediatr Radiol 2015; 45:337-44. [PMID: 25256153 DOI: 10.1007/s00247-014-3176-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 07/24/2014] [Accepted: 08/22/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND New CT reconstruction techniques may help reduce the burden of ionizing radiation. OBJECTIVE To quantify radiation dose reduction when performing pediatric chest CT using a low-dose protocol and 50% adaptive statistical iterative reconstruction (ASIR) compared with age/gender-matched chest CT using a conventional dose protocol and reconstructed with filtered back projection (control group) and to determine its effect on image quality in normal weight and overweight children. MATERIALS AND METHODS We retrospectively reviewed 40 pediatric chest CT (M:F = 21:19; range: 0.1-17 years) in both groups. Radiation dose was compared between the two groups using paired Student's t-test. Image quality including noise, sharpness, artifacts and diagnostic acceptability was subjectively assessed by three pediatric radiologists using a four-point scale (superior, average, suboptimal, unacceptable). RESULTS Eight children in the ASIR group and seven in the control group were overweight. All radiation dose parameters were significantly lower in the ASIR group (P < 0.01) with a greater than 57% dose reduction in overweight children. Image noise was higher in the ASIR group in both normal weight and overweight children. Only one scan in the ASIR group (1/40, 2.5%) was rated as diagnostically suboptimal and there was no unacceptable study. CONCLUSION In both normal weight and overweight children, the ASIR technique is associated with a greater than 57% mean dose reduction, without significantly impacting diagnostic image quality in pediatric chest CT examinations. However, CT scans in overweight children may have a greater noise level, even when using the ASIR technique.
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Affiliation(s)
- Haesung Yoon
- Department of Radiology and Research Institute of Radiological Science, Severance Children's Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, Republic of Korea
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22
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Akhlaghi P, Miri-Hakimabad H, Rafat-Motavalli L. Effects of shielding the radiosensitive superficial organs of ORNL pediatric phantoms on dose reduction in computed tomography. J Med Phys 2014; 39:238-46. [PMID: 25525312 PMCID: PMC4258732 DOI: 10.4103/0971-6203.144490] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 11/04/2022] Open
Abstract
In computed tomography (CT), some superficial organs which have increased sensitivity to radiation, receive doses that are significant enough to be matter of concern. Therefore, in this study, the effects of using shields on the amount of dose reduction and image quality was investigated for pediatric imaging. Absorbed doses of breasts, eyes, thyroid and testes of a series of pediatric phantoms without and with different thickness of bismuth and lead were calculated by Monte Carlo simulation. Appropriate thicknesses of shields were chosen based on their weights, X-ray spectrum, and the amount of dose reduction. In addition, the effect of lead shield on image quality of a simple phantom was assessed quantitatively using region of interest (ROI) measurements. Considering the maximum reduction in absorbed doses and X-ray spectrum, using a lead shield with a maximum thickness of 0.4 mm would be appropriate for testes and thyroid and two other organs (which are exposed directly) should be protected with thinner shields. Moreover, the image quality assessment showed that lead was associated with significant increases in both noise and CT attenuation values, especially in the anterior of the phantom. Overall, the results suggested that shielding is a useful optimization tool in CT.
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Affiliation(s)
- Parisa Akhlaghi
- Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Hashem Miri-Hakimabad
- Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Laleh Rafat-Motavalli
- Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran
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Kritsaneepaiboon S, Siriwanarangsun P, Tanaanantarak P, Krisanachinda A. Can a revised paediatric radiation dose reduction CT protocol be applied and still maintain anatomical delineation, diagnostic confidence and overall imaging quality? Br J Radiol 2014; 87:20140032. [PMID: 24959737 DOI: 10.1259/bjr.20140032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To compare multidetector CT (MDCT) radiation doses between default settings and a revised dose reduction protocol and to determine whether the diagnostic confidence can be maintained with imaging quality made under the revised protocol in paediatric head, chest and abdominal CT studies. METHODS The study retrospectively reviewed head, chest, abdominal and thoracoabdominal MDCT studies, comparing 231 CT studies taken before (Phase 1) and 195 CT studies taken after (Phase 2) the implemented revised protocol. Image quality was assessed using a five-point grading scale based on anatomical criteria, diagnostic confidence and overall quality. Image noise and dose-length product (DLP) were collected and compared. RESULTS The relative dose reductions between Phase 1 and Phase 2 were statistically significant in 35%, 51% and 54% (p < 0.001) of head, chest and abdominal CT studies, respectively. There were no statistically significant differences in overall image quality score comparisons in the head (p = 0.3), chest (p = 0.7), abdominal (p = 0.7) and contiguous thoracic (p = 0.1) and abdominal (p = 0.2) CT studies, with the exception of anatomical quality in definition of bronchial walls and delineation of intrahepatic portal branches in thoracoabdominal CTs, and diagnostic confidence in mass lesion in head CTs, liver lesion (>1 cm), splanchnic venous thrombosis, pancreatitis in abdominal CTs, and emphysema and aortic dissection in thoracoabdominal CTs. CONCLUSION Paediatric CT radiation doses can be significantly reduced from manufacturer's default protocol while still maintaining anatomical delineation, diagnostic confidence and overall imaging quality. ADVANCES IN KNOWLEDGE Revised paediatric CT protocol can provide a half DLP reduction while preserving overall imaging quality.
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Affiliation(s)
- S Kritsaneepaiboon
- 1 Department of Radiology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand
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24
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Adams JE, Engelke K, Zemel BS, Ward KA. Quantitative computer tomography in children and adolescents: the 2013 ISCD Pediatric Official Positions. J Clin Densitom 2014; 17:258-74. [PMID: 24792821 DOI: 10.1016/j.jocd.2014.01.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 01/14/2014] [Indexed: 12/24/2022]
Abstract
In 2007, International Society of Clinical Densitometry Pediatric Positions Task Forces reviewed the evidence for the clinical application of peripheral quantitative computed tomography (pQCT) in children and adolescents. At that time, numerous limitations regarding the clinical application of pQCT were identified, although its use as a research modality for investigation of bone strength was highlighted. The present report provides an updated review of evidence for the clinical application of pQCT, as well as additional reviews of whole body QCT scans of the central and peripheral skeletons, and high-resolution pQCT in children. Although these techniques remain in the domain of research, this report summarizes the recent literature and evidence of the clinical applicability and offers general recommendations regarding the use of these modalities in pediatric bone health assessment.
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Affiliation(s)
- Judith E Adams
- Department of Clinical Radiology, The Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Oxford Road, Manchester, England, UK.
| | - Klaus Engelke
- Institute of Medical Physics, University of Erlangen, Erlangen, Germany and Synarc A/S, Germany
| | - Babette S Zemel
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, The Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Kate A Ward
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK
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25
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Abstract
The purpose of this study is to define an Exposure Index for CT (EI(CT)) and to estimate the magnitude of the EI(CT) for common clinical CT examinations. For a single-axial rotation of a CT X-ray tube that includes only rays that pass through the patient, the CT Exposure Index (EI(CT)) is defined as the average Air Kerma that would be incident on an extended 360° detector array completely surrounding the patient. For an axial scan of a uniform cylindrical phantom, EI(CT) can be approximated as T × [(CTDI(air))/4] × [β°/360°] where T is the fractional transmission through the cylinder, CTDI(air) is the CT Dosimetry Index-determined 'free in air' at isocentre, and β/2 is the fan beam angle that will completely irradiate a cylindrical phantom at isocentre. The value of CTDI(air) can be estimated from the weighted CTDI (CTDI(w)) for a given CT examination, and the angle β depends on the irradiation geometry that can be obtained from the cylinder diameter (r) and the focus to isocentre distance (R). At a voltage of 120 kV, transmission through an adult head was ∼2.6%, through an adult abdomen∼0.4% and through a 5-y-old paediatric abdomen ∼3%. Average ratios of CTDI(air)/CTDI(w) were 1.42 ± 0.12 in 16-cm dosimetry phantom and 2.82 ± 0.37 in 32-cm phantom. Values of β ranged from 30.1° (R = 61 cm and r=8 cm) to 85.3° (R = 55 cm and r=20 cm). For an adult head CT examination, EI(CT) was estimated to be∼70 µGy at a CTDI(vol) of 75 mGy (16 cm), and for an adult abdominal CT examination, EI(CT) was estimated to be∼11 µGy at a CTDI(vol) of 25 mGy (32 cm). For an abdomen CT examination in a 5-y-old child, EI(CT) was estimated to be ∼21 µGy at a CTDI(vol) of 20 mGy (16 cm). The EI(CT) is introduced that provides a quantitative measure of the amount of the radiation used to generate images in any CT examination and is analogous to the average image receptor Exposure Index recently proposed for use in projection imaging. The EI(CT) metric provides operators with an objective index of the amount of the radiation used to create CT images and can be used to control quantum mottle in CT.
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Affiliation(s)
- Walter Huda
- Department of Radiology and Radiological Science, 96 Jonathan Lucas Street, MSC 323, Charleston, SC 29425-3230, USA
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26
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Oliai C, Yang LX. Radioprotectants to reduce the risk of radiation-induced carcinogenesis. Int J Radiat Biol 2013; 90:203-13. [PMID: 24164532 DOI: 10.3109/09553002.2014.859762] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Development of radioprotective agents has focused primarily on cytoprotection from relatively high doses of therapeutic radiation and nuclear disasters. Epidemiological studies and radiobiological models report the potential for stochastic effects from relatively low-dose radiation exposure. Diagnostic studies like computed tomography (CT) expose the patient to a small but significant amount of radiation, which has been reported to increase the risk for carcinogenesis. Young patients expected to undergo multiple CT studies may benefit from a protective agent given prior to CT. This review includes published data of agents that have been shown to protect against radiation-induced carcinogenesis. A discussion follows regarding the data that describes the extent of radiation exposure during CT, as well as technical modifications, which also reduce radiation exposure. RESULTS/CONCLUSIONS Most experiments have used in vivo animal models or in vitro cell lines. Ethical barriers prevent large-scale human studies, although, there are two prospective human studies from the Chernobyl nuclear accident. Collectively, all of these studies provide evidence of statistically significant reductions in radiation-induced carcinogenesis. Protection is achieved by several mechanisms, which include free radical scavenging, caloric restriction, non-steroidal anti-inflammatory agents, humoral factors, and an oxidative agent. Enhanced efficacy is achieved when targeting multiple mechanisms. The data presented provides the scientific foundation for future development of a radioprotectant that may reduce the risk of carcinogenesis from low-dose exposure when certain at-risk populations undergo diagnostic studies like CT.
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Affiliation(s)
- Caspian Oliai
- Department of Radiation Oncology, California Pacific Medical Center , San Francisco, CA , USA
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Abstract
The use of computed tomography (CT) in pediatric diagnostic imaging is demanding generally, but when coupled with an awareness to limit the radiation dose associated with this imaging modality, the procedure becomes challenging. Although new techniques have been developed in line with the introduction of faster multidetector computed tomography (MDCT) scanners to aid radiation reduction, it still remains the responsibility of the clinical practitioner to ensure each examination request is justified and the scanning protocol and parameters selected are optimized to the individual patient's requirement. It is the purpose of this article to outline the basic principle of CT radiation dose optimization based on modification of scanning parameters and application of different imaging techniques.
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Affiliation(s)
- Carolyn Young
- Cardio-respiratory Unit, UCL Institute of Child Health,
London, UK
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Thia LP, Calder A, Stocks J, Bush A, Owens CM, Wallis C, Young C, Sullivan Y, Wade A, McEwan A, Brody AS. Is chest CT useful in newborn screened infants with cystic fibrosis at 1 year of age? Thorax 2013; 69:320-7. [PMID: 24132911 PMCID: PMC3963531 DOI: 10.1136/thoraxjnl-2013-204176] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Rationale Sensitive outcome measures applicable in different centres to quantify and track early pulmonary abnormalities in infants with cystic fibrosis (CF) are needed both for clinical care and interventional trials. Chest CT has been advocated as such a measure yet there is no validated scoring system in infants. Objectives The objectives of this study were to standardise CT data collection across multiple sites; ascertain the incidence of bronchial dilatation and air trapping in newborn screened (NBS) infants with CF at 1 year; and assess the reproducibility of Brody-II, the most widely used scoring system in children with CF, during infancy. Methods A multicentre observational study of early pulmonary lung disease in NBS infants with CF at age 1 year using volume-controlled chest CT performed under general anaesthetic. Main results 65 infants with NBS-diagnosed CF had chest CT in three centres. Small insignificant variations in lung recruitment manoeuvres but significant centre differences in radiation exposures were found. Despite experienced scorers and prior training, with the exception of air trapping, inter- and intraobserver agreement on Brody-II score was poor to fair (eg, interobserver total score mean (95% CI) κ coefficient: 0.34 (0.20 to 0.49)). Only 7 (11%) infants had a total CT score ≥12 (ie, ≥5% maximum possible) by either scorer. Conclusions In NBS infants with CF, CT changes were very mild at 1 year, and assessment of air trapping was the only reproducible outcome. CT is thus of questionable value in infants of this age, unless an improved scoring system for use in mild CF disease can be developed.
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Affiliation(s)
- Lena P Thia
- Portex Unit: Respiratory Physiology and Medicine, UCL Institute of Child Health, , London, UK
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Gay F, Pavia Y, Pierrat N, Lasalle S, Neuenschwander S, Brisse HJ. Dose reduction with adaptive statistical iterative reconstruction for paediatric CT: phantom study and clinical experience on chest and abdomen CT. Eur Radiol 2013; 24:102-11. [DOI: 10.1007/s00330-013-2982-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 07/03/2013] [Accepted: 07/17/2013] [Indexed: 01/21/2023]
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Kataria B, Smedby Ö. Patient dose and image quality in low-dose abdominal CT: a comparison between iterative reconstruction and filtered back projection. Acta Radiol 2013; 54:540-8. [PMID: 23474768 DOI: 10.1177/0284185113476019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND In computed tomography (CT), there is increasing concern for potential CT radiation hazards. Several raw-data-based iterative reconstruction techniques attempt to facilitate low-dose imaging without compromising image quality, which raises the question whether these techniques may allow further dose reduction. PURPOSE To compare image quality of iterative reconstruction and filtered back projection in low-dose abdominal CT and study the potential for further dose reduction. MATERIAL AND METHODS Forty-five patients underwent CT of the abdomen twice: with standard low-dose technique and with 30% reduced dose, using both iterative reconstruction and filtered back projection. Four radiologists made pair-wise image quality assessment using five visual criteria. Visual grading regression (VGR) and weighted kappa (κ w) were used to analyze the data. RESULTS There were significant effects of log(mAs) (P <0.001) and reconstruction algorithm (P <0.01) on all image quality criteria with an estimated potential dose reduction of 5-9%. Inter-observer agreement ranged from 70% to 91% and κ w from -0.01 to 0.57. CONCLUSION An iterative reconstruction algorithm improved image quality in abdominal CT, but the estimated dose reduction was rather small. The full potential of the algorithm remains unclear.
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Affiliation(s)
- Bharti Kataria
- Vrinnevi Hostpital, Norrköping
- Department of Medicine and Health (IMH), Linköping University, Linköping
| | - Örjan Smedby
- Department of Medicine and Health (IMH), Linköping University, Linköping
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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Lee EY, Zucker EJ, Restrepo R, Daltro P, Boiselle PM. Advanced large airway CT imaging in children: evolution from axial to 4-D assessment. Pediatr Radiol 2013; 43:285-97. [PMID: 23417254 DOI: 10.1007/s00247-012-2470-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/09/2012] [Indexed: 12/13/2022]
Abstract
Continuing advances in multidetector computed tomography (MDCT) technology are revolutionizing the non-invasive evaluation of congenital and acquired large airway disorders in children. For example, the faster scanning time and increased anatomical coverage that are afforded by MDCT are especially beneficial to children. MDCT also provides high-quality multiplanar 2-dimensional (2-D), internal and external volume-rendering 3-dimensional (3-D), and dynamic 4-dimensional (4-D) imaging. These advances have enabled CT to become the primary non-invasive imaging modality of choice for the diagnosis, treatment planning, and follow-up evaluation of various large airway disorders in infants and children. It is thus essential for radiologists to be familiar with safe and effective techniques for performing MDCT and to be able to recognize the characteristic imaging appearances of large airway disorders affecting children.
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Affiliation(s)
- Edward Y Lee
- Departments of Radiology and Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Kalra MK, Quick P, Singh S, Sandborg M, Persson A. Whole spine CT for evaluation of scoliosis in children: feasibility of sub-milliSievert scanning protocol. Acta Radiol 2013; 54:226-30. [PMID: 23138023 DOI: 10.1258/ar.2012.110625] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Optimization of CT radiation dose is important for children due to their higher risk of radiation-induced adverse effects. Anatomical structures with high inherent contrast, such as bones can be imaged at very low radiation doses by optimizing scan parameters. PURPOSE To assess feasibility of sub-milliSievert whole spine CT scanning protocol for evaluation of scoliosis in children. MATERIAL AND METHODS With approval of the ethical board, we performed whole spine CT for evaluation of scoliosis in 22 children (age range, 3-18 years; mean age, 13 years; 13 girls, 9 boys) on a 128-slice dual source multidetector-row CT scanner. Lowest possible quality reference mAs value (image quality factor for xy-z automatic exposure control or xyz-AEC, CARE Dose 4D) was selected on a per patient basis. Remaining parameters were held constant at 3.0:1 pitch, 128 × 0.6 mm detector collimation, 115.2 mm table feed per gantry rotation, 100 kVp, and 1 and 3 mm reconstructed sections. Average mAs, projected estimated dose savings with AEC, computed tomography dose index volume (CTDI vol), and dose length product (DLP) were recorded. Artifacts were graded on a four-point scale (1, no artifacts; 4, severe artifacts). Ability to identify vertebral and pedicular contours, and measure pedicular width and degree of vertebral rotation was graded on a three-point scale (1, unacceptable; 3, excellent). RESULTS All CT examinations were deemed as reliable for identifying vertebral and pedicular contours as well as for measuring pedicular width (5.9 ± 1.6 mm) and degree of vertebral rotation (28.7 ± 23.4°). Mean objective image noise and signal to noise ratio (SNR) were 57.5 ± 21.5 and 4.7 ± 2.3, respectively. With a mean quality reference mAs of 13, the scanner employed an average actual effective mAs of 10 ± 3.8 (range, 6-18 mAs) with an estimated radiation dose saving of 43.5 ± 16.3% with xyz-AEC compared with fixed mAs. The mean CTDI, DLP, and estimated effective doses were 0.4 ± 0.1 mGy (0.2-0.7 mGy), 21 ± 10 mGy.cm (8-41 mGy.cm), and 0.3 ± 0.1 mSv (0.12-0.64 mSv), respectively. CONCLUSION Radiation dose for whole spine CT for evaluation of scoliosis in children can be minimized to less than one-third of a milliSievert while maintaining diagnostic image quality.
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Affiliation(s)
- Mannudeep K Kalra
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
- Massachusetts General Hospital Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Petter Quick
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
| | - Sarabjeet Singh
- Massachusetts General Hospital Imaging, Massachusetts General Hospital, Boston, MA, USA
| | - Michael Sandborg
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
- Department of Radiophysics, Linkoping University Hospital, Linkoping, Sweden
| | - Anders Persson
- Center for Medical Image Science and Visualization (CMIV), Linkoping University, Linkoping University Hospital, Linkoping, Sweden
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Dobeli KL, Lewis SJ, Meikle SR, Thiele DL, Brennan PC. Noise-reducing algorithms do not necessarily provide superior dose optimisation for hepatic lesion detection with multidetector CT. Br J Radiol 2013; 86:20120500. [PMID: 23392194 DOI: 10.1259/bjr.20120500] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE To compare the dose-optimisation potential of a smoothing filtered backprojection (FBP) and a hybrid FBP/iterative algorithm to that of a standard FBP algorithm at three slice thicknesses for hepatic lesion detection with multidetector CT. METHODS A liver phantom containing a 9.5-mm opacity with a density of 10 HU below background was scanned at 125, 100, 75, 50 and 25 mAs. Data were reconstructed with standard FBP (B), smoothing FBP (A) and hybrid FBP/iterative (iDose(4)) algorithms at 5-, 3- and 1-mm collimation. 10 observers marked opacities using a four-point confidence scale. Jackknife alternative free-response receiver operating characteristic figure of merit (FOM), sensitivity and noise were calculated. RESULTS Compared with the 125-mAs/5-mm setting for each algorithm, significant reductions in FOM (p<0.05) and sensitivity (p<0.05) were found for all three algorithms for all exposures at 1-mm thickness and for all slice thicknesses at 25 mAs, with the exception of the 25-mAs/5-mm setting for the B algorithm. Sensitivity was also significantly reduced for all exposures at 3-mm thickness for the A algorithm (p<0.05). Noise for the A and iDose(4) algorithms was approximately 13% and 21% lower, respectively, than for the B algorithm. CONCLUSION Superior performance for hepatic lesion detection was not shown with either a smoothing FBP algorithm or a hybrid FBP/iterative algorithm compared with a standard FBP technique, even though noise reduction with thinner slices was demonstrated with the alternative approaches. ADVANCES IN KNOWLEDGE Reductions in image noise with non-standard CT algorithms do not necessarily translate to an improvement in low-contrast object detection.
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Affiliation(s)
- K L Dobeli
- Medical Image Optimisation and Perception Group (MIOPeG), Medical Imaging & Radiation Sciences Faculty Research Group, Faculty of Health Sciences, University of Sydney, Sydney, Australia.
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Rodrigues SI, Abrantes AF, Ribeiro LP, Almeida RPP. Estudo da dose nos exames de tomografia computadorizada abdominal em um equipamento de 6 cortes. Radiol Bras 2012. [DOI: 10.1590/s0100-39842012000600008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Determinar a dose efetiva recebida nos exames de tomografia computadorizada abdominal e estudar a influência das características dos pacientes na dose recebida. MATERIAIS E MÉTODOS: Foram realizadas medições dos valores de dose com uma câmara de ionização em objetos simuladores, de forma a verificar se os valores obtidos estavam de acordo com os valores apresentados pelo equipamento de tomografia computadorizada e se estes não ultrapassavam os níveis de referência de dose recomendados. Posteriormente, foram medidos os valores de dose recebida pelos pacientes, com autonomia física, nos exames de tomografia computadorizada abdominal (n = 100) e a relação existente com as suas características antropométricas. Por último, foi simulada a dose nos órgãos por meio do método de Monte Carlo utilizando o software de simulação CT-Expo V 1.5, e estudado o efeito do controle automático de exposição nestes exames. RESULTADOS: As principiais características com influência direta na dose são a massa corporal, o perímetro abdominal e o índice de massa corporal do paciente, cuja relação é linear e positiva. CONCLUSÃO: A dose de radiação recebida nos exames abdominais depende de algumas características dos pacientes, sendo importante ajustar os parâmetros de aquisição às suas dimensões.
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Brady SL, Yee BS, Kaufman RA. Characterization of adaptive statistical iterative reconstruction algorithm for dose reduction in CT: A pediatric oncology perspective. Med Phys 2012; 39:5520-31. [PMID: 22957619 DOI: 10.1118/1.4745563] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PURPOSE This study demonstrates a means of implementing an adaptive statistical iterative reconstruction (ASiR™) technique for dose reduction in computed tomography (CT) while maintaining similar noise levels in the reconstructed image. The effects of image quality and noise texture were assessed at all implementation levels of ASiR™. Empirically derived dose reduction limits were established for ASiR™ for imaging of the trunk for a pediatric oncology population ranging from 1 yr old through adolescence∕adulthood. METHODS Image quality was assessed using metrics established by the American College of Radiology (ACR) CT accreditation program. Each image quality metric was tested using the ACR CT phantom with 0%-100% ASiR™ blended with filtered back projection (FBP) reconstructed images. Additionally, the noise power spectrum (NPS) was calculated for three common reconstruction filters of the trunk. The empirically derived limitations on ASiR™ implementation for dose reduction were assessed using (1, 5, 10) yr old and adolescent∕adult anthropomorphic phantoms. To assess dose reduction limits, the phantoms were scanned in increments of increased noise index (decrementing mA using automatic tube current modulation) balanced with ASiR™ reconstruction to maintain noise equivalence of the 0% ASiR™ image. RESULTS The ASiR™ algorithm did not produce any unfavorable effects on image quality as assessed by ACR criteria. Conversely, low-contrast resolution was found to improve due to the reduction of noise in the reconstructed images. NPS calculations demonstrated that images with lower frequency noise had lower noise variance and coarser graininess at progressively higher percentages of ASiR™ reconstruction; and in spite of the similar magnitudes of noise, the image reconstructed with 50% or more ASiR™ presented a more smoothed appearance than the pre-ASiR™ 100% FBP image. Finally, relative to non-ASiR™ images with 100% of standard dose across the pediatric phantom age spectrum, similar noise levels were obtained in the images at a dose reduction of 48% with 40% ASIR™ and a dose reduction of 82% with 100% ASIR™. CONCLUSIONS The authors' work was conducted to identify the dose reduction limits of ASiR™ for a pediatric oncology population using automatic tube current modulation. Improvements in noise levels from ASiR™ reconstruction were adapted to provide lower radiation exposure (i.e., lower mA) instead of improved image quality. We have demonstrated for the image quality standards required at our institution, a maximum dose reduction of 82% can be achieved using 100% ASiR™; however, to negate changes in the appearance of reconstructed images using ASiR™ with a medium to low frequency noise preserving reconstruction filter (i.e., standard), 40% ASiR™ was implemented in our clinic for 42%-48% dose reduction at all pediatric ages without a visually perceptible change in image quality or image noise.
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Affiliation(s)
- S L Brady
- Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA.
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Kritsaneepaiboon S, Trinavarat P, Visrutaratna P. Survey of pediatric MDCT radiation dose from university hospitals in Thailand: a preliminary for national dose survey. Acta Radiol 2012; 53:820-6. [PMID: 22821958 DOI: 10.1258/ar.2012.110641] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Increasing pediatric CT usage worldwide needs the optimization of CT protocol examination. Although there are previous published dose reference level (DRL) values, the local DRLs should be established to guide for clinical practice and monitor the CT radiation. PURPOSE To determine the multidetector CT (MDCT) radiation dose in children in three university hospitals in Thailand in four age groups using the CT dose index (CTDI) and dose length product (DLP). MATERIAL AND METHODS A retrospective review of CT dosimetry in pediatric patients (<15 years of age) who had undergone head, chest, and abdominal MDCT in three major university hospitals in Thailand was performed. Volume CTDI (CTDI(vol)) and DLP were recorded, categorized into four age groups: <1 year, 1-< 5 years, 5-<10 years, and 10-<15 years in each scanner. Range, mean, and third quartile values were compared with the national reference dose levels for CT in pediatric patients from the UK and Switzerland according to International Commission on Radiological Protection (ICRP) recommendation. Results Per age group, the third quartile values for brain, chest, and abdominal CTs were, respectively, in terms of CTDI(vol): 25, 30, 40, and 45 mGy; 4.5, 5.7, 10, and 15.6 mGy; 8.5, 9, 14, and 17 mGy; and in terms of DLP: 400, 570, 610, and 800 mGy cm; 80, 140, 305, and 470 mGy cm; and 190, 275, 560,765 mGy cm. CONCLUSION This preliminary national dose survey for pediatric CT in Thailand found that the majority of CTDI(vol) and DLP values in brain, chest, and abdominal CTs were still below the diagnostic reference levels (DRLs) from the UK and Switzerland regarding to ICRP recommendation.
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Affiliation(s)
| | | | - Pannee Visrutaratna
- Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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IAEA survey of pediatric CT practice in 40 countries in Asia, Europe, Latin America, and Africa: Part 1, frequency and appropriateness. AJR Am J Roentgenol 2012; 198:1021-31. [PMID: 22528891 DOI: 10.2214/ajr.11.7273] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE The purpose of this study was to assess the frequency of pediatric CT in 40 less-resourced countries and to determine the level of appropriateness in CT use. MATERIALS AND METHODS Data on the increase in the number of CT examinations during 2007 and 2009 and appropriate use of CT examinations were collected, using standard forms, from 146 CT facilities at 126 hospitals. RESULTS The lowest frequency of pediatric CT examinations in 2009 was in European facilities (4.3%), and frequencies in Asia (12.2%) and Africa (7.8%) were twice as high. Head CT is the most common CT examination in children, amounting to nearly 75% of all pediatric CT examinations. Although regulations in many countries assign radiologists with the main responsibility of deciding whether a radiologic examination should be performed, in fact, radiologists alone were responsible for only 6.3% of situations. Written referral guidelines for imaging were not available in almost one half of the CT facilities. Appropriateness criteria for CT examinations in children did not always follow guidelines set by agencies, in particular, for patients with accidental head trauma, infants with congenital torticollis, children with possible ventriculoperitoneal shunt malfunction, and young children (< 5 years old) with acute sinusitis. In about one third of situations, nonavailability of previous images and records on previously received patient doses have the potential to lead to unnecessary examinations and radiation doses. CONCLUSION With increasing use of CT in children and a lack of use of appropriateness criteria, there is a strong need to implement guidelines to avoid unnecessary radiation doses to children.
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Sonoda LI, Sanghera B, Wong WL. Investigation of dose minimisation protocol for 18F-FDG PET-CT in the management of lymphoma postchemotherapy followup. ScientificWorldJournal 2012; 2012:208135. [PMID: 22545010 PMCID: PMC3324157 DOI: 10.1100/2012/208135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 11/16/2011] [Indexed: 02/05/2023] Open
Abstract
INTRODUCTION (18)F-FDG-PET-CT plays an important role in the management of lymphoma postchemotherapy followup. Some centres perform prechemotherapy baseline CT and postchemotherapy PETCT. With a concern of radiation burden, especially in young patients, this study aimed to assess if PETCT radiation dose could be reduced. METHODS Retrospective analysis of 100 lymphoma patients was performed to record sites of disease on prechemotherapy CT and postchemotherapy PETCT. The potential reduction in radiation and time achieved with PETCT limited to sites of known disease identified on prechemotherapy CT was calculated. RESULTS No FDG-uptake was seen in 72 cases. FDG uptake at known disease sites was seen in 24. Of the remaining 4, one had clinically significant pathology, a rectal adenocarcinoma. PETCT did not reveal any unexpected sites of lymphoma. Limiting PETCT to sites of known disease would have saved a mean radiation dose of 4 mSv (27.3%), with a mean time of 16 minutes. CONCLUSION Our study suggests that young patients may benefit from reduced radiation by limiting PETCT to sites of known disease with low risk of missing significant pathology. However, in older patients, with increased incidence of asymptomatic synchronous malignancies, whole-body PETCT is advisable unless prechemotherapy PETCT has been performed.
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Affiliation(s)
- L I Sonoda
- Paul Strickland Scanner Centre, Mount Vernon Hospital, Northwood, Middlesex HA6 2RN, UK.
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Paediatric multi-detector row chest CT: what you really need to know. Insights Imaging 2012; 3:229-46. [PMID: 22696085 PMCID: PMC3369117 DOI: 10.1007/s13244-012-0152-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 01/09/2012] [Accepted: 01/24/2012] [Indexed: 11/16/2022] Open
Abstract
Background The emergence of multi-detector row CT (MDCT) has established and extended the role of CT especially in paediatric chest imaging. This has altered the way in which data is acquired and is perceived as the 'gold standard' in the detection of certain chest pathologies. The range of available post-processing tools provide alternative ways in which CT images can be manipulated for review and interpretation in order to enhance diagnostic accuracy. Methodology Paediatric imaging technique/protocol together with radiation dose reduction is discussed in detail. The use of different post-processing tools to best demonstrate the wide range of important congenital anomalies and thoracic pathologies is outlined and presented pictorially. Conclusion MDCT with its isotropic resolution and fast imaging acquisition times reduces the need for invasive diagnostic investigations. However, users must be vigilant in their imaging techniques to minimise radiation burden, whilst maintaining good image quality. Main Messages • CT examinations should be clinically justified by the referring clinician and radiologist. • MDCT is invaluable for evaluating the central airway, mediastinal structures and lung parenchyma. • MDCT is more sensitive than plain radiographs in detection of structural changes within the lungs.
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Pauwels EKJ, Bourguignon MH. Radiation dose features and solid cancer induction in pediatric computed tomography. Med Princ Pract 2012; 21:508-15. [PMID: 22472997 DOI: 10.1159/000337404] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 01/24/2012] [Indexed: 12/17/2022] Open
Abstract
Over the past two decades technical advances and improvements have made computed tomography (CT) a valuable and essential tool in the array of diagnostic imaging modalities. CT uses ionizing radiation (X-rays) which may damage DNA and increase the risk of carcinogenesis. This is especially pertinent in pediatric CT as children are more radiosensitive and have a longer life expectancy than adults. The purpose of this paper is to review and elucidate the potential harmful effects of ionizing radiation in terms of solid cancer induction from pediatric CT scanning. In the light of scientific and technical developments, we will also discuss the possible strategies and ongoing efforts to reduce CT radiation exposure in pediatric patients. In this context, we will not ignore the fact that a well-justified CT scan may exceed its risk and have a favorable impact.
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Affiliation(s)
- Ernest K J Pauwels
- Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands. ernestpauwels @ gmail.com
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Sun Z, Al Ghamdi KS, Baroum IH. Multislice CT of the head and body routine scans: Are scanning protocols adjusted for paediatric patients? Biomed Imaging Interv J 2012; 8:e3. [PMID: 22970059 PMCID: PMC3432222 DOI: 10.2349/biij.8.1.e3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2011] [Revised: 11/08/2011] [Accepted: 11/08/2011] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To investigate whether the multislice CT scanning protocols of head, chest and abdomen are adjusted according to patient's age in paediatric patients. MATERIALS AND METHODS Multislice CT examination records of paediatric patients undergoing head, chest and abdomen scans from three public hospitals during a one-year period were retrospectively reviewed. Patients were categorised into the following age groups: under 4 years, 5-8 years, 9-12 years and 13-16 years, while the tube current was classified into the following ranges: < 49 mA, 50-99 mA, 100-149 mA, 150-199 mA, > 200 mA and unknown. RESULTS A total of 4998 patient records, comprising a combination of head, chest and abdomen CT scans, were assessed, with head CT scans representing nearly half of the total scans. Age-based adjusted CT protocols were observed in most of the scans with higher tube current setting being used with increasing age. However, a high tube current (150-199 mA) was still used in younger patients (0-8 years) undergoing head CT scans. In one hospital, CT protocols remained constant across all age groups, indicating potential overexposure to the patients. CONCLUSION This analysis shows that paediatric CT scans are adjusted according to the patient's age in most of the routine CT examinations. This indicates increased awareness regarding radiation risks associated with CT. However, high tube current settings are still used in younger patient groups, thus, optimisation of paediatric CT protocols and implementation of current guidelines, such as age-and weight-based scanning, should be recommended in daily practice.
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Affiliation(s)
- Z Sun
- Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth, Australia
| | - KS Al Ghamdi
- Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, Perth, Australia
| | - IH Baroum
- Department of Radiology, King Abdul Aziz Hospital and Oncology Centre, Jeddah, Saudi Arabia
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42
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Abstract
Computerized tomography (CT) is an extremely powerful imaging modality, which provides extremely valuable information for the diagnosis, staging, and management of pediatric solid tumors. In recent years, the concern of potential risks associated with ionizing radiation from diagnostic imaging - especially from CT - has greatly increased. In children with cancer the radiation burden from CT studies can easily accumulate because of repeated studies for disease staging, assessment of response to therapy, and follow up. The purpose of this article is to review the role of CT and its imaging key points for diagnosis, staging and planning surgical excision of common extracranial pediatric tumors, according to protocol specific imaging guidelines. The issue of the radiation burden from CT in children with cancer, and criteria of good practice to reduce it, will also be discussed.
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Affiliation(s)
- Claudio Granata
- Department of Radiology, IRCCS Giannina Gaslini Hospital, Genoa, Italy.
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43
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Siripornpitak S, Pornkul R, Khowsathit P, Layangool T, Promphan W, Pongpanich B. Cardiac CT angiography in children with congenital heart disease. Eur J Radiol 2011; 82:1067-82. [PMID: 22196744 DOI: 10.1016/j.ejrad.2011.11.042] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cardiac imaging plays an important role in both congenital and acquired heart diseases. Cardiac computed tomography (angiography) cCT(A) is a non-invasive, increasingly popular, complementary modality to echocardiography in evaluation of congenital heart diseases (CHD) in children. Despite radiation exposure, cCT(A) is now commonly used for evaluation of the complex CHD, giving information of both intra-cardiac and extra-cardiac anatomy, coronary arteries, and vascular structures. This review article will focus on the fundamentals and essentials for performing cCT(A) in children, including radiation dose awareness, basic techniques, and strengths and weaknesses of cCT(A) compared with cardiac magnetic resonance imaging (cMRI), and applications. The limitations of this modality will also be discussed, including the CHD for which cMRI may be substituted.
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Affiliation(s)
- Suvipaporn Siripornpitak
- Division of Diagnostic Radiology, Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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44
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Cardiac computed tomography and conventional angiography in the diagnosis of congenital cardiac disease in children: recent trends and radiation doses. Cardiol Young 2011; 21:616-22. [PMID: 21733206 DOI: 10.1017/s1047951111000485] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The use of imaging that employs ionising radiation is increasing in the setting of paediatric cardiology. Children's high radiosensitivity and the lack of contemporary radiation data warrant a review of the radiation doses from the latest "state-of-the-art" angiography and computed tomography systems. OBJECTIVES In children aged less than 16 years with congenital cardiac disease, we aimed to report: recent trends in the use of diagnostic angiography and cardiac dual-source computed tomography; the characteristics, lesions, and imaging histories of patients undergoing these procedures; and the average radiation doses imparted by each modality. STUDY DESIGN Retrospective review of consecutive cases undergoing cardiac computed tomography or diagnostic angiography in a teaching hospital between January, 2008 and December, 2009. Radiation doses were converted to effective doses (millisievert) using published conversion factors. RESULTS Angiography was performed 3.7 times more often than computed tomography. Computed tomography examinations increased by 92.5%, whereas angiography decreased by 26.4% in 2009 compared with 2008. Patients undergoing computed tomography were younger and weighed less than those undergoing angiography, but lesions were similar between the 2 groups. Multiple lifetime angiography was more prevalent than multiple lifetime computed tomography (p < 0.001). The median procedural dose - range - from angiography and computed tomography was 5 (0.2-27.8) and 1.7 (0.5-9.5) millisieverts, respectively (p < 0.001). CONCLUSION Despite not being completely analogous investigations, computed tomography should be considered prior to angiography and not withheld on radiation dose concerns, given that it imparts lower and more consistent doses than conventional angiography.
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45
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Radiation dose of non-enhanced chest CT can be reduced 40% by using iterative reconstruction in image space. Clin Radiol 2011; 66:1023-9. [DOI: 10.1016/j.crad.2011.04.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 03/31/2011] [Accepted: 04/08/2011] [Indexed: 12/22/2022]
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46
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Hitter A, Hullo E, Durand C, Righini CA. Diagnostic value of various investigations in children with suspected foreign body aspiration. Eur Ann Otorhinolaryngol Head Neck Dis 2011; 128:248-52. [DOI: 10.1016/j.anorl.2010.12.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/17/2010] [Accepted: 12/27/2010] [Indexed: 11/29/2022]
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47
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Pauwels EKJ, Bourguignon M. Cancer induction caused by radiation due to computed tomography: a critical note. Acta Radiol 2011; 52:767-73. [PMID: 21742785 DOI: 10.1258/ar.2011.100496] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The considerable rise of computed tomography (CT) procedures over the past few decades has urged responsible authorities and researchers to evaluate the risk of carcinogenesis in the population in relation to the radiation dose delivered to the patient. A single patient undergoing CT may receive a radiation equivalent dose that varies between about 2 mSv (head ) to about 20 mSv (CT-based coronary angiography). Whereas the latter represents a substantial dose delivered to one patient it is, however, population-wise far below the area of the so-called low doses, i.e. 50 mSv in children and 100 mSv in adults. While at effective doses above 50 mSv the risk of cancer induction increases linearly with dose, this dose-response relation has not been demonstrated at doses below 50 mSv. Below 50 mSv no convincing epidemiological evidence for cancer risk exists. Calculations on this risk are based on scientifically questionable, if not invalid, extrapolations of data from higher doses. However, the failure to demonstrate that a risk of cancer exists does not mean that there is no risk. This paper summarizes the data mentioned in various articles from recent literature discussing cancer risks due to CT and puts the results of these studies in perspective of current scientific knowledge in the field of radiation protection. For this we follow the lead of the ICRP and UNSCEAR. Furthermore, we review the strategies and efforts of various national and international bodies and manufacturers of CT apparatus to lower the radiation dose to the patient.
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Affiliation(s)
- Ernest K J Pauwels
- Leiden University Medical Center, Department of Radiology, Leiden, The Netherlands
- Pisa University Medical School, University of Pisa, Pisa, Italy
| | - Michel Bourguignon
- Université de Versailles Saint Quentin en Yvelines, Department of Biophysics and Autorité de Sureté Nucléaire, Paris, France
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48
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Abstract
Primary malignant bone tumors are rare and account for about 6% of all new pediatric cancer cases per year in the United States. Identification of the lesion not uncommonly occurs as a result of imaging performed for trauma. Clinical and standard imaging characteristics of the various tumor types are evolving in concert with treatment advancements and clinical trial regimens. This article reviews the 3 most common pediatric bone sarcomas-osteosarcoma, Ewing sarcoma, and chondrosarcoma-and their imaging as applicable to contemporary disease staging and monitoring, and explores the roles of evolving imaging techniques.
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Affiliation(s)
- Sue C Kaste
- Department of Radiological Sciences, St. Jude Children's Research Hospital, MSN #220, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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49
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Abstract
Computed tomography (CT) is a powerful tool for the accurate and effective diagnosis and treatment of a variety of conditions because it allows high-resolution three-dimensional images to be acquired very quickly. However as the number of CT procedures performed globally have continued to increase; with growing concerns about patient protection. Currently, no system is in place to track patient doses and the lifetime cumulative dose from medical sources. The widespread use of CT even in developing countries has raised questions regarding the possible threat to public health especially in children. The best available risk estimates suggest that paediatric CT will result in significantly increased lifetime radiation risk over adult CT. Studies have shown that lower milliampere-second (mAs) settings can be used for children without significant loss of information. Although the risk-benefit balance is still strongly tilted toward benefit, there is still need for caution. Furthermore since the frequency of paediatric CT examinations is rapidly increasing, and estimates suggest that quantitative lifetime radiation risks for children are not negligible, efforts should be made toward more active reduction of CT exposure settings in paediatric patients. This article hopes to address this concerns and draw attention to the fact that children are not 'small adults ' and should therefore be treated differently.
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50
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Ahmed BA, Connolly BL, Shroff P, Chong AL, Gordon C, Grant R, Greenberg ML, Thomas KE. Cumulative effective doses from radiologic procedures for pediatric oncology patients. Pediatrics 2010; 126:e851-8. [PMID: 20876178 DOI: 10.1542/peds.2009-2675] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Our aim was to estimate the cumulative effective doses (CEDs) from radiologic procedures for a cohort of pediatric oncology patients. METHODS A retrospective cohort study of the imaging histories of 150 pediatric oncology patients (30 each in 5 subgroups, that is, leukemia, lymphomas, brain tumors, neuroblastomas, and assorted solid tumors) for 5 years after diagnosis was performed. All procedures involving ionizing radiation were recorded, including radiography, computed tomography (CT), nuclear medicine (NM) studies, fluoroscopy, and interventional procedures. CED estimates were calculated. RESULTS Individual CED estimates ranged from <1 mSv to 642 mSv, with a median of 61 mSv. CT and NM were the greatest contributors; CT constituted 30% of procedures but 52% of the total CED, and NM constituted 20% and 46%, respectively. There was considerable variability between tumor subgroups. CED estimates were highest in the neuroblastoma (median: 213 mSv [range: 36-489 mSv]) and lymphoma (median: 191 mSv [range: 10-642 mSv]) groups and lowest in the leukemia group (median: 5 mSv [range: 0.2-57 mSv]). CONCLUSIONS CEDs from diagnostic and interventional imaging for pediatric oncology patients vary considerably according to diagnoses, individual clinical courses, and imaging modalities used. Increased awareness may promote strategies to reduce the radiation burden to this population.
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Affiliation(s)
- Bilal A Ahmed
- Hospital for Sick Children, Department of Diagnostic Imaging, and Department of Medical Imaging, University of Toronto, 555 University Ave, Toronto, Ontario M5G 1X8, Canada
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