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Huang ZH, Liu YY, Wu WJ, Huang KW. Design and Validation of a Deep Learning Model for Renal Stone Detection and Segmentation on Kidney-Ureter-Bladder Images. Bioengineering (Basel) 2023; 10:970. [PMID: 37627855 PMCID: PMC10452034 DOI: 10.3390/bioengineering10080970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
Kidney-ureter-bladder (KUB) imaging is used as a frontline investigation for patients with suspected renal stones. In this study, we designed a computer-aided diagnostic system for KUB imaging to assist clinicians in accurately diagnosing urinary tract stones. The image dataset used for training and testing the model comprised 485 images provided by Kaohsiung Chang Gung Memorial Hospital. The proposed system was divided into two subsystems, 1 and 2. Subsystem 1 used Inception-ResNetV2 to train a deep learning model on preprocessed KUB images to verify the improvement in diagnostic accuracy with image preprocessing. Subsystem 2 trained an image segmentation model using the ResNet hybrid, U-net, to accurately identify the contours of renal stones. The performance was evaluated using a confusion matrix for the classification model. We conclude that the model can assist clinicians in accurately diagnosing renal stones via KUB imaging. Therefore, the proposed system can assist doctors in diagnosis, reduce patients' waiting time for CT scans, and minimize the radiation dose absorbed by the body.
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Affiliation(s)
- Zih-Hao Huang
- Department of Electrical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 807618, Taiwan; (Z.-H.H.); (Y.-Y.L.); (W.-J.W.)
| | - Yi-Yang Liu
- Department of Electrical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 807618, Taiwan; (Z.-H.H.); (Y.-Y.L.); (W.-J.W.)
- Department of Urology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung City 83301, Taiwan
| | - Wei-Juei Wu
- Department of Electrical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 807618, Taiwan; (Z.-H.H.); (Y.-Y.L.); (W.-J.W.)
| | - Ko-Wei Huang
- Department of Electrical Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 807618, Taiwan; (Z.-H.H.); (Y.-Y.L.); (W.-J.W.)
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Choi TW, Chung JW, Kwon Y. Modified design of x-ray protective clothing to enhance radiation protection for interventional radiologists. Med Phys 2023. [PMID: 36794321 DOI: 10.1002/mp.16309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 02/01/2023] [Accepted: 02/01/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND In interventional radiology procedures, the operator typically stands on the right side of the patient's right thigh to manipulate devices through the femoral sheath. Because the standard x-ray protective clothing is designed as sleeveless and scatter radiations from the patient are mainly incident from the left-anterior direction to the operator, the arm hole of the clothing may be a significant unprotected area, contributing to an increase in the operator's organ doses and effective dose. PURPOSE This study aimed to compare the organ doses and effective dose received by the interventional radiologist when wearing the standard x-ray protective clothing and when wearing the modified clothing with an additional shoulder guard. METHODS The experimental setup aimed to simulate actual clinical practice in interventional radiology. The patient phantom was located at the beam center to generate scatter radiation. An adult female anthropomorphic phantom loaded with 126 nanoDots (Landauer Inc., Glenwood, IL) was used to measure organ and effective doses to the operator. The standard wrap-around type x-ray protective clothing offered 0.25-mm lead-equivalent protection, and the frontal overlap area offered 0.50-mm lead-equivalent protection. The shoulder guard was custom-made with a material providing x-ray protection equivalent to lead of 0.50 mm thickness. The organ and effective doses were compared between the operator wearing the standard protective clothing and the one wearing the modified clothing with a shoulder guard. RESULTS After adding the shoulder guard, doses to the lungs, bone marrow, and esophagus decreased by 81.9%, 58.6%, and 58.7%, respectively, and the effective dose to the operator decreased by 47.7%. CONCLUSIONS Widespread use of modified x-ray protective clothing with shoulder guards can significantly decrease the overall occupational radiation risk in interventional radiology.
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Affiliation(s)
- Tae Won Choi
- Department of Radiology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Jin Wook Chung
- Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.,Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Yohan Kwon
- Department of Radiology, Ajou University School of Medicine, Suwon, Republic of Korea
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Deep Learning Model for Computer-Aided Diagnosis of Urolithiasis Detection from Kidney-Ureter-Bladder Images. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 9:bioengineering9120811. [PMID: 36551017 PMCID: PMC9774756 DOI: 10.3390/bioengineering9120811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Kidney-ureter-bladder (KUB) imaging is a radiological examination with a low cost, low radiation, and convenience. Although emergency room clinicians can arrange KUB images easily as a first-line examination for patients with suspicious urolithiasis, interpreting the KUB images correctly is difficult for inexperienced clinicians. Obtaining a formal radiology report immediately after a KUB imaging examination can also be challenging. Recently, artificial-intelligence-based computer-aided diagnosis (CAD) systems have been developed to help clinicians who are not experts make correct diagnoses for further treatment more effectively. Therefore, in this study, we proposed a CAD system for KUB imaging based on a deep learning model designed to help first-line emergency room clinicians diagnose urolithiasis accurately. A total of 355 KUB images were retrospectively collected from 104 patients who were diagnosed with urolithiasis at Kaohsiung Chang Gung Memorial Hospital. Then, we trained a deep learning model with a ResNet architecture to classify KUB images in terms of the presence or absence of kidney stones with this dataset of pre-processed images. Finally, we tuned the parameters and tested the model experimentally. The results show that the accuracy, sensitivity, specificity, and F1-measure of the model were 0.977, 0.953, 1, and 0.976 on the validation set and 0.982, 0.964, 1, and 0.982 on the testing set, respectively. Moreover, the results demonstrate that the proposed model performed well compared to the existing CNN-based methods and was able to detect urolithiasis in KUB images successfully. We expect the proposed approach to help emergency room clinicians make accurate diagnoses and reduce unnecessary radiation exposure from computed tomography (CT) scans, along with the associated medical costs.
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Reference phantom selection in pediatric computed tomography using data from a large, multicenter registry. Pediatr Radiol 2022; 52:445-452. [PMID: 34866159 PMCID: PMC8857172 DOI: 10.1007/s00247-021-05227-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/09/2021] [Accepted: 10/12/2021] [Indexed: 10/25/2022]
Abstract
BACKGROUND Radiation dose metrics vary by the calibration reference phantom used to report doses. By convention, 16-cm diameter cylindrical polymethyl-methacyrlate phantoms are used for head imaging and 32-cm diameter phantoms are used for body imaging in adults. Actual usage patterns in children remain under-documented. OBJECTIVE This study uses the University of California San Francisco International CT Dose Registry to describe phantom selection in children by patient age, body region and scanner manufacturer, and the consequent impact on radiation doses. MATERIALS AND METHODS For 106,837 pediatric computed tomography (CT) exams collected between Jan. 1, 2015, and Nov. 2, 2020, in children up to 17 years of age from 118 hospitals and imaging facilities, we describe reference phantom use patterns by body region, age and manufacturer, and median and 75th-percentile dose-length product (DLP) and volume CT dose index (CTDIvol) doses when using 16-cm vs. 32-cm phantoms. RESULTS There was relatively consistent phantom selection by body region. Overall, 98.0% of brain and skull examinations referenced 16-cm phantoms, and 95.7% of chest, 94.4% of abdomen and 100% of cervical-spine examinations referenced 32-cm phantoms. Only GE deviated from this practice, reporting chest and abdomen scans using 16-cm phantoms with some frequency in children up to 10 years of age. DLP and CTDIvol values from 16-cm phantom-referenced scans were 2-3 times higher than 32-cm phantom-referenced scans. CONCLUSION REFERENCE PHANTOM SELECTION IS HIGHLY CONSISTENT, WITH A SMALL BUT SIGNIFICANT NUMBER OF ABDOMEN AND CHEST SCANS (~5%) USING 16-CM PHANTOMS IN YOUNGER CHILDREN, WHICH PRODUCES DLP VALUES APPROXIMATELY TWICE AS HIGH AS EXAMS REFERENCED TO 32-CM PHANTOMS.
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Bagherzadeh S, Jabbari N, Khalkhali HR. Radiation dose and cancer risks from radiation exposure during abdominopelvic computed tomography (CT) scans: comparison of diagnostic and radiotherapy treatment planning CT scans. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:579-589. [PMID: 34542682 DOI: 10.1007/s00411-021-00942-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/04/2021] [Indexed: 06/13/2023]
Abstract
In the present study, radiation doses and cancer risks resulting from abdominopelvic radiotherapy planning computed tomography (RP-CT) and abdominopelvic diagnostic CT (DG-CT) examinations are compared. Two groups of patients who underwent abdominopelvic CT scans with RP-CT (n = 50) and DG-CT (n = 50) voluntarily participated in this study. The two groups of patients had approximately similar demographic features including mass, height, body mass index, sex, and age. Radiation dose parameters included CTDIvol, dose-length product, scan length, effective tube current, and pitch factor, all taken from the CT scanner console. The ImPACT software was used to calculate the patient-specific radiation doses. The risks of cancer incidence and mortality were estimated based on the BEIR VII report of the US National Research Council. In the RP-CT group, the mean ± standard deviation of cancer incidence risk for all cancers, leukemia, and all solid cancers was 621.58 ± 214.76, 101.59 ± 27.15, and 516.60 ± 189.01 cancers per 100,000 individuals, respectively, for male patients. For female patients, the corresponding risks were 742.71 ± 292.35, 74.26 ± 20.26, and 667.03 ± 275.67 cancers per 100,000 individuals, respectively. In contrast, for DG-CT cancer incidence risks were 470.22 ± 170.07, 78.23 ± 18.22, and 390.25 ± 152.82 cancers per 100,000 individuals for male patients, while they were 638.65 ± 232.93, 62.14 ± 13.74, and 575.73 ± 221.21 cancers per 100,000 individuals for female patients. Cancer incidence and mortality risks were greater for RP-CT than for DG-CT scans. It is concluded that the various protocols of abdominopelvic CT scans, especially the RP-CT scans, should be optimized with respect to the radiation doses associated with these scans.
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Affiliation(s)
- Saeed Bagherzadeh
- Department of Medical Physics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Nasrollah Jabbari
- Solid Tumor Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran.
| | - Hamid Reza Khalkhali
- Patient Safety Research Center, Department of Biostatistics and Epidemiology, Urmia University of Medical Sciences, Urmia, Iran
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Fujii K, Nomura K, Muramatsu Y, Goto T, Obara S, Ota H, Tsukagoshi S. Correlation analysis of organ doses determined by Monte Carlo simulation with dose metrics for patients undergoing chest-abdomen-pelvis CT examinations. Phys Med 2020; 77:1-9. [DOI: 10.1016/j.ejmp.2020.07.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 07/04/2020] [Accepted: 07/12/2020] [Indexed: 01/09/2023] Open
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Radiation dose of chaperones during common pediatric computed tomography examinations. Pediatr Radiol 2020; 50:1078-1082. [PMID: 32415324 PMCID: PMC7329757 DOI: 10.1007/s00247-020-04681-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 03/02/2020] [Accepted: 04/15/2020] [Indexed: 10/27/2022]
Abstract
BACKGROUND One main challenge in pediatric imaging is to reduce motion artifacts by calming young patients. To that end, the Radiological Society of North America (RSNA) as early as 1997 stated the necessity of adults accompanying their child during the child's examination. Nonetheless, current research lacks data regarding radiation dose to these chaperones. OBJECTIVE The aim of this study was to measure the radiation dose of accompanying adults during state-of-the-art pediatric CT protocols. MATERIALS AND METHODS In addition to a 100-kV non-contrast-enhanced chest CT (Protocol 1), we performed a 70-kV contrast-enhanced chest protocol (Protocol 2) using a third-generation dual-source CT. We acquired data on the radiation dose around the scanner using digital dosimetry placed right at the gantry, 1 m away, as well as beside the gantry. We acquired the CT-surrounding radiation dose during scanning of a pediatric phantom as well as 12 pediatric patients. RESULTS After conducting 10 consecutive phantom scans using Protocol 1, we found the location with the highest cumulative dose acquired was right next to the gantry opening, at 3 μSv. Protocol 2 showed highest cumulative dose of 2 μSv at the same location. For Protocol 1, the location with the highest radiation doses during pediatric scans was right next to the gantry opening, with doses of 0.75±0.70 μSv. For Protocol 2, the highest radiation was measured 1 m away at 0.50±0.60 μSv. No radiation dose was measured at any time beside the gantry. CONCLUSION Our results provide proof that chaperones receive low radiation doses during state-of-the-art CT examinations. Given knowledge of these values as well as the optimal spots with the lowest radiation doses, parents as well as patients might be more relaxed during the examination.
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Kostou T, Papadimitroulas P, Papaconstadopoulos P, Devic S, Seuntjens J, Kagadis GC. Size-specific dose estimations for pediatric chest, abdomen/pelvis and head CT scans with the use of GATE. Phys Med 2019; 65:181-190. [PMID: 31494372 DOI: 10.1016/j.ejmp.2019.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/24/2019] [Accepted: 08/29/2019] [Indexed: 01/17/2023] Open
Abstract
PURPOSE The purpose of this study is to create an organ dose database for pediatric individuals undergoing chest, abdomen/pelvis, and head computed tomography (CT) examinations, and to report the differences in absorbed organ doses, when anatomical differences exist for pediatric patients. METHODS The GATE Monte Carlo (MC) toolkit was used to model the GE BrightSpeed Elite CT model. The simulated scanner model was validated with the standard Computed Tomography Dose Index (CTDI) head phantom. Twelve computational models (2.1-14 years old) were used. First, contributions to effective dose and absorbed doses per CTDIvol and per 100 mAs were estimated for all organs. Then, doses per CTDIvol were correlated with patient model weight for the organs inside the scan range for chest and abdomen/pelvis protocols. Finally, effective doses per dose-length product (DLP) were estimated and compared with the conventional conversion k-factors. RESULTS The system was validated against experimental CTDIw measurements. The doses per CTDIvol and per 100 mAs for selected organs were estimated. The magnitude of the dependency between the dose and the anatomical characteristics was calculated with the coefficient of determination at 0.5-0.7 for the internal scan organs for chest and abdomen/pelvis protocols. Finally, effective doses per DLP were compared with already published data, showing discrepancies between 13 and 29% and were correlated strongly with the total weight (R2 > 0.8) for the chest and abdomen protocols. CONCLUSIONS Big differences in absorbed doses are reported even for patients of similar age or same gender, when anatomical differences exist on internal organs of the body.
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Affiliation(s)
- Theodora Kostou
- University of Patras, Department of Medical Physics, Patras, Greece
| | | | | | - Slobodan Devic
- McGill University, Department of Medical Physics, Montreal, Canada
| | - Jan Seuntjens
- McGill University, Department of Medical Physics, Montreal, Canada
| | - George C Kagadis
- University of Patras, Department of Medical Physics, Patras, Greece.
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Fujii K, Nomura K, Muramatsu Y, Obara S, Goto T, Akahane K, Ota H, Tsukagoshi S, Kusumoto M. VALIDATION OF MONTE CARLO DOSE CALCULATION FOR PAEDIATRIC CT EXAMINATIONS USING TUBE CURRENT MODULATION BASED ON IN-PHANTOM DOSIMETRY. RADIATION PROTECTION DOSIMETRY 2018; 182:508-517. [PMID: 30032259 DOI: 10.1093/rpd/ncy109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
The aim of this study is to estimate tube current modulation (TCM) profiles in paediatric computed tomography (CT) examinations with a TCM scheme (Volume-EC) and evaluate the estimation accuracy of TCM profiles. Another aim is to validate organ doses calculated using Monte Carlo-based CT dosimetry software and estimated TCM profiles by comparing them with those measured using 5-year-old and 10-year-old anthropomorphic phantoms and radio-photoluminescence glass dosemeters. Dose calculations were performed by inputting detailed descriptions of a CT scanner, scan parameters and CT images of the phantoms into the software. Organ doses were evaluated from the calculated dose distribution images. Average relative differences (RDs) between the estimated and actual TCM profiles ranged from -3.6 to 5.6%. RDs between the calculated and measured organ doses ranged from -4.2 to 13.0% and -18.1 to 4.9% for 5-year-old and 10-year-old phantoms, respectively. These results validate dose calculations for paediatric CT scans using TCM.
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Affiliation(s)
- K Fujii
- Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Japan
- Department of Radiological Technology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
- Department of Radiation Measurement and Dose Assessment, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - K Nomura
- Department of Radiological Technology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - Y Muramatsu
- Department of Radiological Technology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - S Obara
- Department of Radiation Measurement and Dose Assessment, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - T Goto
- Canon Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi, Japan
| | - K Akahane
- Department of Radiation Measurement and Dose Assessment, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - H Ota
- Department of Radiological Technology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - S Tsukagoshi
- Canon Medical Systems Corporation, 1385 Shimoishigami, Otawara, Tochigi, Japan
| | - M Kusumoto
- Department of Diagnostic Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
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Bagherzadeh S, Jabbari N, Khalkhali HR. Estimation of lifetime attributable risks (LARs) of cancer associated with abdominopelvic radiotherapy treatment planning computed tomography (CT) simulations. Int J Radiat Biol 2018. [PMID: 29528791 DOI: 10.1080/09553002.2018.1450536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE The present study attempts to calculate organ-absorbed and effective doses for cancer patients to estimate the possible cancer induction and cancer mortality risks resulting from 64-slice abdominopelvic computed tomography (CT) simulations for radiotherapy treatment planning (RTTP). MATERIAL AND METHODS A group of 70 patients, who underwent 64-slice abdominopelvic CT scan for RTTP, voluntarily participated in the present study. To calculate organ and effective doses in a standard phantom of 70 kg, the collected dosimetric parameters were used with the ImPACT CT Patient Dosimetry Calculator. Patient-specific organ dose and effective dose were calculated by applying related correction factors. For the estimation of lifetime attributable risks (LARs) of cancer incidence and cancer-related mortality, doses in radiosensitive organs were converted to risks based on the data published in Biological Effects of Ionizing Radiation VII (BEIR VII). RESULTS The mean ± standard deviation (SD) of the effective dose for males and females were 13.87 ± 2.37 mSv (range: 9.25-18.82 mSv) and 13.04 ± 3.42 mSv (range: 6.99-18.37 mSv), respectively. The mean ± SD of LAR of cancer incidence was 35.34 ± 13.82 cases in males and 34.49 ± 9.63 cases in females per 100,000 persons. The LAR of cancer mortality had the mean ± SD value of 15.38 ± 4.25 and 16.72 ± 3.87 cases per 100,000 persons in males and females respectively. CONCLUSION Increase in the LAR of cancer occurrence and mortality due to abdominopelvic treatment planning CT simulation is noticeable and should be considered.
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Affiliation(s)
- Saeed Bagherzadeh
- a Department of Medical Physics, School of Medicine , Urmia University of Medical Sciences , Urmia , Iran
| | - Nasrollah Jabbari
- b Solid Tumor Research Center , Urmia University of Medical Sciences , Urmia , Iran
| | - Hamid Reza Khalkhali
- c Patient Safety Research Center, Department of Biostatistics and Epidemiology , Urmia University of Medical Sciences , Urmia , Iran
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Fujii K, Nomura K, Muramatsu Y, Obara S, Akahane K, Kusumoto M. Organ Dose Evaluations Based on Monte Carlo Simulation for CT Examinations Using Tube Current Modulation. RADIATION PROTECTION DOSIMETRY 2017; 174:387-394. [PMID: 27342451 DOI: 10.1093/rpd/ncw144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 05/25/2016] [Indexed: 06/06/2023]
Abstract
The aims of this study were to estimate tube current values for each X-ray projection angle used in adult chest computed tomography (CT) and abdomen-pelvis CT examinations with tube current modulation (TCM) and to validate organ doses determined using Monte Carlo (MC) simulations through comparisons with the doses measured using in-phantom dosimetry. For dose simulations, dose distribution images were obtained by inputting the geometry of a CT scanner, scan parameters including estimated TCM curves and CT images of an adult anthropomorphic phantom into MC simulation software. Organ doses were then determined from the dose distribution images. For dose measurements, organ doses were evaluated using radio-photoluminescence glass dosemeters located at various organ positions within the phantom. Relative differences between the simulated and measured organ doses were -2.5 to 11.0% and -1.5 to 10.5% for organs in chest and abdomen-pelvis CT scan ranges, respectively. Thus, the simulated and measured doses agreed well.
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Affiliation(s)
- K Fujii
- Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Japan
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - K Nomura
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - Y Muramatsu
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - S Obara
- Department of Radiation Measurement and Dose Assessment, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - K Akahane
- Department of Radiation Measurement and Dose Assessment, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - M Kusumoto
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
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Gao Y, Quinn B, Mahmood U, Long D, Erdi Y, St. Germain J, Pandit-Taskar N, Xu XG, Bolch WE, Dauer LT. A comparison of pediatric and adult CT organ dose estimation methods. BMC Med Imaging 2017; 17:28. [PMID: 28446130 PMCID: PMC5406971 DOI: 10.1186/s12880-017-0199-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 04/11/2017] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Computed Tomography (CT) contributes up to 50% of the medical exposure to the United States population. Children are considered to be at higher risk of developing radiation-induced tumors due to the young age of exposure and increased tissue radiosensitivity. Organ dose estimation is essential for pediatric and adult patient cancer risk assessment. The objective of this study is to validate the VirtualDose software in comparison to currently available software and methods for pediatric and adult CT organ dose estimation. METHODS Five age groups of pediatric patients and adult patients were simulated by three organ dose estimators. Head, chest, abdomen-pelvis, and chest-abdomen-pelvis CT scans were simulated, and doses to organs both inside and outside the scan range were compared. For adults, VirtualDose was compared against ImPACT and CT-Expo. For pediatric patients, VirtualDose was compared to CT-Expo and compared to size-based methods from literature. Pediatric to adult effective dose ratios were also calculated with VirtualDose, and were compared with the ranges of effective dose ratios provided in ImPACT. RESULTS In-field organs see less than 60% difference in dose between dose estimators. For organs outside scan range or distributed organs, a five times' difference can occur. VirtualDose agrees with the size-based methods within 20% difference for the organs investigated. Between VirtualDose and ImPACT, the pediatric to adult ratios for effective dose are compared, and less than 21% difference is observed for chest scan while more than 40% difference is observed for head-neck scan and abdomen-pelvis scan. For pediatric patients, 2 cm scan range change can lead to a five times dose difference in partially scanned organs. CONCLUSIONS VirtualDose is validated against CT-Expo and ImPACT with relatively small discrepancies in dose for organs inside scan range, while large discrepancies in dose are observed for organs outside scan range. Patient-specific organ dose estimation is possible using the size-based methods, and VirtualDose agrees with size-based method for the organs investigated. Careful range selection for CT protocols is necessary for organ dose optimization for pediatric and adult patients.
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Affiliation(s)
- Yiming Gao
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
| | - Brian Quinn
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
| | - Usman Mahmood
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
| | - Daniel Long
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
| | - Yusuf Erdi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
| | - Jean St. Germain
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
| | - Neeta Pandit-Taskar
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 USA
| | - X. George Xu
- Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 USA
| | - Wesley E. Bolch
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611 USA
| | - Lawrence T. Dauer
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 84, New York, NY 10065 USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 USA
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Yamauchi-Kawaura C, Fujii K, Akahane K, Yamauchi M, Obara S, Narai K, Katsu T, Imai K, Ikeda M. DEVELOPMENT OF AGE-SPECIFIC JAPANESE PHYSICAL PHANTOMS FOR DOSE EVALUATION IN INFANT CT EXAMINATIONS. RADIATION PROTECTION DOSIMETRY 2016; 171:483-502. [PMID: 26420904 DOI: 10.1093/rpd/ncv420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 09/03/2015] [Accepted: 09/04/2015] [Indexed: 06/05/2023]
Abstract
Secondary to the previous development of age-specific Japanese head phantoms, the authors designed Japanese torso phantoms for dose assessment in infant computed tomography (CT) examinations and completed a Japanese 3-y-old head-torso phantom. For design of age-specific torso phantoms (0, 0.5, 1 and 3 y old), anatomical structures were measured from CT images of Japanese infant patients. From the CT morphometry, it was found that rib cages of Japanese infants were smaller than those in Europeans and Americans. Radiophotoluminescence glass dosemeters were used for dose measurement of a 3-y-old head-torso phantom. To examine the validity of the developed phantom, organ and effective doses by the in-phantom dosimetry system were compared with simulation values in a web-based CT dose calculation system (WAZA-ARI). The differences in doses between the two systems were <20 % at the doses of organs within scan regions and effective doses in head, chest and abdominopelvic CT examinations.
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Affiliation(s)
- C Yamauchi-Kawaura
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - K Fujii
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - K Akahane
- Medical Exposure Research Promotion Section, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - M Yamauchi
- Division of Radiology, Aichi Medical University Hospital, Nagakute, Aichi 480-1195, Japan
| | - S Obara
- Medical Exposure Research Promotion Section, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - K Narai
- Techno-Rad, Inc., 50-8, Higashi Arami, Tai, Miyama-cho, Kuze-gun, Kyoto 613-0036, Japan
| | - T Katsu
- Division of Radiology, Nagoya University Hospital, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan
| | - K Imai
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - M Ikeda
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
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14
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Nakao M, Obara S, Nabatame K, Akahane K, Sanada S, Shirai T. Estimation of organ doses and effective doses in image-guided respiration-gated radiotherapy. RADIATION PROTECTION DOSIMETRY 2016; 168:83-91. [PMID: 25848094 DOI: 10.1093/rpd/ncv015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 02/05/2015] [Indexed: 06/04/2023]
Abstract
Dose conformity in thoracic and abdominal ion-beam radiotherapy is degraded by respiratory motion. To improve conformity, an image-guided respiration-gated system can be used in the treatment room. The purpose of this study was to estimate the organ doses and effective doses to patients from an image-guided respiration-gated system. Glass dosemeters were inserted into an adult anthropomorphic phantom and were attached to the surface on the phantom. The phantom was placed on the treatment couch, and the imaging dose from fluoroscopy was evaluated. In addition to the organ doses, the effective doses were also estimated according to the ICRP Publication 103. The irradiation time is over 3-5 min per beam angle. When image acquisition conditions were assumed for thoracic treatment, the effective doses and maximal skin doses were 0.48-0.79 mSv and 5.9-9.9 mGy, respectively. The estimated doses can be the base data for considering radiological protection in the radiotherapy.
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Affiliation(s)
- Minoru Nakao
- National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
| | - Satoshi Obara
- National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Kuniaki Nabatame
- National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Keiichi Akahane
- National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Shigeru Sanada
- Kanazawa University, 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
| | - Toshiyuki Shirai
- National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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15
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Suliman II, Khamis HM, Ombada TH, Alzimami K, Alkhorayef M, Sulieman A. Radiation exposure during paediatric CT in Sudan: CT dose, organ and effective doses. RADIATION PROTECTION DOSIMETRY 2015; 167:513-518. [PMID: 25377750 DOI: 10.1093/rpd/ncu321] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 09/24/2014] [Indexed: 06/04/2023]
Abstract
The purpose of this study was to assess the magnitude of radiation exposure during paediatric CT in Sudanese hospitals. Doses were determined from CT acquisition parameters using CT-Expo 2.1 dosimetry software. Doses were evaluated for three patient ages (0-1, 1-5 and 5-10 y) and two common procedures (head and abdomen). For children aged 0-1 y, volume CT air kerma index (Cvol), air Kerma-length product and effective dose (E) values were 19.1 mGy, 265 mGy.cm and 3.1 mSv, respectively, at head CT and those at abdominal CT were 8.8 mGy, 242 mGy.cm and 7.7 mSv, respectively. Those for children aged 1-5 y were 22.5 mGy, 305 mGy.cm and 1.1 mSv, respectively, at head CT and 12.6 mGy, 317 mGy.cm, and 5.1 mSv, respectively, at abdominal CT. Dose values and variations were comparable with those reported in the literature. Organ equivalent doses vary from 7.5 to 11.6 mSv for testes, from 9.0 to 10.0 mSv for ovaries and from 11.1 to 14.3 mSv for uterus in abdominal CT. The results are useful for dose optimisation and derivation of national diagnostic reference levels.
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Affiliation(s)
- I I Suliman
- Department of Radiology and Molecular Imaging, Medical Physics Section, College of Medicine and Health Sciences, Sultan Qaboos University, PO Box 35, 123 Al-Khod, Oman Sudan Atomic Energy Commission, Radiation Safety Institute, PO Box 3001, Khartoum, Sudan
| | - H M Khamis
- Sudan Atomic Energy Commission, Radiation Safety Institute, PO Box 3001, Khartoum, Sudan
| | - T H Ombada
- Faculty of Science and Technology, Department of Medical Physics, Al-Neelain University, PO Box 12702, Khartoum, Sudan
| | - K Alzimami
- Department of Radiological Sciences, Applied Medical Sciences College, King Saud University, PO Box 10219, Riyadh 11433, Saudi Arabia
| | - M Alkhorayef
- Department of Radiological Sciences, Applied Medical Sciences College, King Saud University, PO Box 10219, Riyadh 11433, Saudi Arabia
| | - A Sulieman
- Radiology and Medical Imaging Department, College of Applied Medical Sciences, Salman Bin Abdulaziz University, PO Box 422, Alkharj 11943, Saudi Arabia
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16
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Inkoom S, Raissaki M, Perisinakis K, Maris TG, Damilakis J. Location of radiosensitive organs inside pediatric anthropomorphic phantoms: Data required for dosimetry. Phys Med 2015; 31:882-888. [DOI: 10.1016/j.ejmp.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 06/04/2015] [Accepted: 06/05/2015] [Indexed: 11/29/2022] Open
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Fujii K, Nomura K, Muramatsu Y, Takahashi K, Obara S, Akahane K, Satake M. Evaluation of organ doses in adult and paediatric CT examinations based on Monte Carlo simulations and in-phantom dosimetry. RADIATION PROTECTION DOSIMETRY 2015; 165:166-171. [PMID: 25848103 DOI: 10.1093/rpd/ncv074] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of this study was to validate the computed tomography dose index (CTDI) and organ doses evaluated by Monte Carlo simulations through comparisons with doses evaluated by in-phantom dosimetry. Organ doses were measured with radio-photoluminescence glass dosemeter (RGD) set at various organ positions within adult and 1-y-old anthropomorphic phantoms. For the dose simulations, the X-ray spectrum and bow-tie filter shape of a CT scanner were estimated and 3D voxelised data of the CTDI and anthropomorphic phantoms from the acquired CT images were derived. Organ dose simulations and measurements were performed with chest and abdomen-pelvis CT examination scan parameters. Relative differences between the simulated and measured doses were within 5 % for the volume CTDI and 13 % for organ doses for organs within the scan range in adult and paediatric CT examinations. The simulation results were considered to be in good agreement with the measured doses.
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Affiliation(s)
- K Fujii
- Department of Radiological Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Japan Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - K Nomura
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - Y Muramatsu
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - K Takahashi
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
| | - S Obara
- National Institute of Radiological Sciences, Medical Exposure Research Promotion Section, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - K Akahane
- National Institute of Radiological Sciences, Medical Exposure Research Promotion Section, 4-9-1 Anagawa, Inage-ku, Chiba, Japan
| | - M Satake
- Department of Radiology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Japan
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18
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Yamauchi-Kawaura C, Fujii K, Akahane K, Yamauchi M, Narai K, Aoyama T, Katsu T, Obara S, Imai K, Ikeda M. Development of age-specific Japanese head phantoms for dose evaluation in paediatric head CT examinations. RADIATION PROTECTION DOSIMETRY 2015; 163:188-201. [PMID: 24821932 DOI: 10.1093/rpd/ncu155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this study, the authors developed age-specific physical head phantoms simulating the physique of Japanese children for dose evaluation in paediatric head computed tomography (CT) examinations. Anatomical structures at 99 places in 0-, 0.5-, 1- and 3-y-old Japanese patients were measured using DICOM viewer software from CT images, and the head phantom of each age was designed. For trial manufacture, a 3-y-old head phantom consisting of acrylic resin and gypsum was produced by machine processing. Radiation doses for the head phantom were measured with radiophotoluminescence glass dosemeters and Si-pin photodiode dosemeters. To investigate whether the phantom shape was suitable for dose evaluation, organ doses in the same scan protocol were compared between the 3-y-old head and commercially available anthropomorphic phantoms having approximately the same head size. The doses of organs in both phantoms were equivalent. The authors' designed paediatric head phantom will be useful for dose evaluation in paediatric head CT examinations.
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Affiliation(s)
- C Yamauchi-Kawaura
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - K Fujii
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - K Akahane
- Radiological Protection Section, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - M Yamauchi
- Division of Radiology, Aichi Medical University Hospital, Nagakute, Aichi 480-1195, Japan
| | - K Narai
- Techno-Rad, Inc., 50-8, Higashi Arami, Tai, Miyama-cho, Kuze-gun, Kyoto 613-0036, Japan
| | - T Aoyama
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - T Katsu
- Division of Radiology, Nagoya University Hospital, Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan
| | - S Obara
- Radiological Protection Section, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - K Imai
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
| | - M Ikeda
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
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19
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Hwang EH, Ju JK, Cho MJ, Lee JW, Lee HD. Giant coronary aneurysm caused by Kawasaki disease: consistency between catheter angiography and electrocardiogram gated dual-source computed tomography angiography. KOREAN JOURNAL OF PEDIATRICS 2015; 58:501-4. [PMID: 26770226 PMCID: PMC4705331 DOI: 10.3345/kjp.2015.58.12.501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 11/15/2013] [Accepted: 11/18/2013] [Indexed: 11/30/2022]
Abstract
We present the case of a 5-year-old child with coronary complications due to Kawasaki disease; this patient unintentionally underwent both dual-source computed tomography (DSCT) coronary angiography and invasive coronary angiographic examination in 2 months. This case highlights the strong consistency of the results between DSCT coronary angiography and invasive coronary angiography. Compared to conventional invasive coronary angiography, DSCT coronary angiography offered additional advantages such as minimal invasiveness and less radiation exposure.
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Affiliation(s)
- Eun-Ha Hwang
- Department of Pediatrics, Pusan National University Hospital, Busan, Korea
| | - Jung-Ki Ju
- Department of Pediatrics, Good Gang-An Hospital, Busan, Korea
| | - Min-Jung Cho
- Department of Pediatrics, Pusan National University Hospital, Busan, Korea
| | - Ji-Won Lee
- Department of Radiology, Pusan National University Hospital, Busan, Korea
| | - Hyoung-Doo Lee
- Department of Pediatrics, Pusan National University Children's Hospital, Yangsan, Korea
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20
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Yonekura Y, Tsujii H, Hopewell JW, López PO, Cosset JM, Paganetti H, Montelius A, Schardt D, Jones B, Nakamura T. ICRP Publication 127: Radiological Protection in Ion Beam Radiotherapy. Ann ICRP 2014; 43:5-113. [PMID: 25915952 DOI: 10.1177/0146645314559144] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The goal of external-beam radiotherapy is to provide precise dose localisation in the treatment volume of the target with minimal damage to the surrounding normal tissue. Ion beams, such as protons and carbon ions, provide excellent dose distributions due primarily to their finite range, allowing a significant reduction of undesired exposure of normal tissue. Careful treatment planning is required for the given type and localisation of the tumour to be treated in order to maximise treatment efficiency and minimise the dose to normal tissue. Radiation exposure in out-of-field volumes arises from secondary neutrons and photons, particle fragments, and photons from activated materials. These unavoidable doses should be considered from the standpoint of radiological protection of the patient. Radiological protection of medical staff at ion beam radiotherapy facilities requires special attention. Appropriate management and control are required for the therapeutic equipment and the air in the treatment room that can be activated by the particle beam and its secondaries. Radiological protection and safety management should always conform with regulatory requirements. The current regulations for occupational exposures in photon radiotherapy are applicable to ion beam radiotherapy with protons or carbon ions. However, ion beam radiotherapy requires a more complex treatment system than conventional radiotherapy, and appropriate training of staff and suitable quality assurance programmes are recommended to avoid possible accidental exposure of patients, to minimise unnecessary doses to normal tissue, and to minimise radiation exposure of staff.
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21
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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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22
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Kashcheev VV, Pryakhin EA, Menyaylo AN, Chekin SY, Ivanov VK. Comparing risk estimates following diagnostic CT radiation exposures employing different methodological approaches. HEALTH PHYSICS 2014; 106:806-811. [PMID: 24776915 DOI: 10.1097/hp.0000000000000096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The current study has two aims: the first is to quantify the difference between radiation risks estimated with the use of organ or effective doses, particularly when planning pediatric and adult computed tomography (CT) examinations. The second aim is to determine the method of calculating organ doses and cancer risk using dose-length product (DLP) for typical routine CT examinations. In both cases, the radiation-induced cancer risks from medical CT examinations were evaluated as a function of gender and age. Lifetime attributable risk values from CT scanning were estimated with the use of ICRP (Publication 103) risk models and Russian national medical statistics data. For populations under the age of 50 y, the risk estimates based on organ doses usually are 30% higher than estimates based on effective doses. In older populations, the difference can be up to a factor of 2.5. The typical distributions of organ doses were defined for Chest Routine, Abdominal Routine, and Head Routine examinations. The distributions of organ doses were dependent on the anatomical region of scanning. The most exposed organs/tissues were thyroid, breast, esophagus, and lungs in cases of Chest Routine examination; liver, stomach, colon, ovaries, and bladder in cases of Abdominal Routine examination; and brain for Head Routine examinations. The conversion factors for calculation of typical organ doses or tissues at risk using DLP were determined. Lifetime attributable risk of cancer estimated with organ doses calculated from DLP was compared with the risk estimated on the basis of organ doses measured with the use of silicon photodiode dosimeters. The estimated difference in LAR is less than 29%.
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Affiliation(s)
- Valery V Kashcheev
- *Federal State Institution Medical Radiological Research Center of the Russian Ministry of Health, 4 Korolyov str., Obninsk, Kaluga Region, 249036, Russia
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23
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Shuryak I, Lubin JH, Brenner DJ. Potential for adult-based epidemiological studies to characterize overall cancer risks associated with a lifetime of CT scans. Radiat Res 2014; 181:584-91. [PMID: 24828111 DOI: 10.1667/rr13622.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Recent epidemiological studies have suggested that radiation exposure from pediatric CT scanning is associated with small excess cancer risks. However, the majority of CT scans are performed on adults, and most radiation-induced cancers appear during middle or old age, in the same age range as background cancers. Consequently, a logical next step is to investigate the effects of CT scanning in adulthood on lifetime cancer risks by conducting adult-based, appropriately designed epidemiological studies. Here we estimate the sample size required for such studies to detect CT-associated risks. This was achieved by incorporating different age-, sex-, time- and cancer type-dependent models of radiation carcinogenesis into an in silico simulation of a population-based cohort study. This approach simulated individual histories of chest and abdominal CT exposures, deaths and cancer diagnoses. The resultant sample sizes suggest that epidemiological studies of realistically sized cohorts can detect excess lifetime cancer risks from adult CT exposures. For example, retrospective analysis of CT exposure and cancer incidence data from a population-based cohort of 0.4 to 1.3 million (depending on the carcinogenic model) CT-exposed UK adults, aged 25-65 in 1980 and followed until 2015, provides 80% power for detecting cancer risks from chest and abdominal CT scans.
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Affiliation(s)
- Igor Shuryak
- a Center for Radiological Research, Columbia University Medical Center, New York, New York; and
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Yamauchi-Kawaura C, Yamauchi M, Imai K, Ikeda M, Aoyama T. Image quality and age-specific dose estimation in head and chest CT examinations with organ-based tube-current modulation. RADIATION PROTECTION DOSIMETRY 2013; 157:193-205. [PMID: 23734058 DOI: 10.1093/rpd/nct137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The purpose of this study was to investigate the effects of an organ-based tube-current modulation (OBTCM) system on image quality and age-specific dose in head and chest CT examinations. Image noise, contrast-to-noise ratio (CNR) and image entropy were assessed using statistical and entropy analyses. Radiation doses for newborn, 6-y-old child and adult phantoms were measured with in-phantom dosimetry systems. The quality of CT images obtained with OBTCM was not different from that obtained without OBTCM. In head CT scans, the eye lens dose decreased by 20-33 % using OBTCM. In chest CT scans, breast dose decreased by 5-32 % using OBTCM. Posterior skin dose, however, increased by 11-20 % using OBTCM in head and chest CT scans. The reduction of effective dose using OBTCM was negligibly small. Detailed image quality and dose information provided in this study can be effectively used for OBTCM application.
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Affiliation(s)
- C Yamauchi-Kawaura
- Department of Radiological Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daikominami, Higashi-ku, Nagoya 461-8673, Japan
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25
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Kim MC, Han DK, Kim YM, Lim CH, Yeon KJ, Yoon J. Radiation exposure in multidetector CT: dose comparison between late 1990s and early 2010s in Korea. RADIATION PROTECTION DOSIMETRY 2013; 156:429-435. [PMID: 23567199 DOI: 10.1093/rpd/nct088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The effective dose under ordinary clinical computed tomography (CT) protocols using three kinds of 64-channel and a 40-channel CT ranged from 0.6 to 15.5 mSv in early 2010s. And the organ dose ranged from 1.6 to 130.4 mGy: orbital and brain doses for brain stroke CT were the highest. For the comparison of the effective dose between late 1990s and early 2010s, multidetector CT (MDCT) for high-resolution lung CT was 2.4 times higher than that of single-detector CT (SDCT) and the ratio was the highest. However, the effective dose at MDCT was 20 % lower than that of SDCT in chest CT due to applying dose-saving techniques. In organ dose comparisons, high-resolution lung CT at MDCT was 3.5-4.5 times higher than that of SDCT, and showed 1.1-1.5 times higher than that of SDCT in the head and chest CT. For the abdomen CT, the primary organ dose at MDCT was ∼30 % lower than that of SDCT.
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Affiliation(s)
- Moon Chan Kim
- Department of Radiologic Science, Eulji University, Kyungki, Korea
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26
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Matsuzaki Y, Fujii K, Kumagai M, Tsuruoka I, Mori S. Effective and organ doses using helical 4DCT for thoracic and abdominal therapies. JOURNAL OF RADIATION RESEARCH 2013; 54:962-970. [PMID: 23603303 PMCID: PMC3766296 DOI: 10.1093/jrr/rrt024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 02/23/2013] [Accepted: 02/28/2013] [Indexed: 06/02/2023]
Abstract
The capacity of 4DCT to quantify organ motion is beyond conventional 3DCT capability. Local control could be improved. However we are unaware of any reports of organ dose measurements for helical 4DCT imaging. We therefore quantified the radiation doses for helical 4DCT imaging. Organ and tissue dose was measured for thoracic and abdominal 4DCT in helical mode using an adult anthropomorphic phantom. Radiation doses were measured with thermoluminescence dosimeter chips inserted at various anatomical sites on the phantom. For the helical thoracic 4DCT, organ doses were 57.2 mGy for the lung, 76.7 mGy for the thyroids, 48.1 mGy for the breasts, and 10.86 mGy for the colon. The effective doses for male and female phantoms were very similar, with a mean value of 33.1 mSv. For abdominal 4DCT imaging, organ doses were 14.4 mGy for the lung, 0.78 mGy for the thyroids, 9.83 mGy for breasts, and 58.2 mGy for the colon (all obtained by using ICRP 103). We quantified the radiation exposure for thoracic and abdominal helical 4DCT. The doses for helical 4DCT were approximately 1.5 times higher than those for cine 4DCT, however the stepwise image artifact was reduced. 4DCT imaging should be performed with care in order to minimize radiation exposure, but the advantages of 4DCT imaging mandates its incorporation into routine treatment protocols.
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MESH Headings
- Abdominal Neoplasms/diagnostic imaging
- Abdominal Neoplasms/radiotherapy
- Humans
- Imaging, Three-Dimensional/instrumentation
- Imaging, Three-Dimensional/methods
- Phantoms, Imaging
- Radiation Dosage
- Radiography, Abdominal/instrumentation
- Radiography, Abdominal/methods
- Radiography, Thoracic/instrumentation
- Radiography, Thoracic/methods
- Radiotherapy, Image-Guided/methods
- Relative Biological Effectiveness
- Reproducibility of Results
- Respiratory-Gated Imaging Techniques/methods
- Sensitivity and Specificity
- Thoracic Neoplasms/diagnostic imaging
- Thoracic Neoplasms/radiotherapy
- Tomography, X-Ray Computed/instrumentation
- Tomography, X-Ray Computed/methods
- Viscera/diagnostic imaging
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Affiliation(s)
| | | | | | | | - Shinichiro Mori
- Corresponding author. Tel: +81-43-251-2111; Fax: +81-43-284-0198;
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Entrance skin dosimetry and size-specific dose estimate from pediatric chest CTA. J Cardiovasc Comput Tomogr 2013; 8:97-107. [PMID: 24211194 DOI: 10.1016/j.jcct.2013.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 03/27/2013] [Accepted: 08/16/2013] [Indexed: 02/08/2023]
Abstract
BACKGROUND Size-specific dose estimate (SSDE), which corrects CT dose index (CTDI) for body diameter and is a better measure of organ dose than is CTDI, has not yet been validated in vivo. OBJECTIVE The purpose was to determine the correlation between SSDE and measured breast entrance skin dose (ESD) for pediatric chest CT angiography across a variety of techniques, scanner models, and patient sizes. METHODS During 42 examinations done on 4 different scanners over 7 years, we measured mid-sternal ESD as an approximation of breast dose with skin dosimeters. We recorded age, weight, effective tube current, kilovoltage potential, console CTDI, and dose-length product, from which we calculated effective dose. We measured effective chest diameter to convert CTDI to SSDE, and we correlated SSDE with measured ESD, using linear regression. We evaluated image quality to answer the clinical question. RESULTS Patient mean (±SD) age was 8.4 ± 6.1 years (median, 7.9 years; range, 0.02-19.5 years); mean weight was 35 ± 27 kg (median, 26 kg; range, 3.5-115 kg); effective chest diameter was 20 ± 7 cm (median, 19 cm; range, 10-35 cm). Mean effective dose was 2.9 ± 2.8 mSv (median, 2.2 mSv; range, 0.1-14.4 mSv). We observed a linear correlation (R(2) = 0.98, P < .005) between SSDE (mean, 11 ± 11mGy; median, 7 mGy; range, 0.5-40 mGy) and breast ESD (mean, 12 ± 11 mGy; median, 7 mGy; range, 0.3-44 mGy). Our doses, which compared favorably with those previously reported, decreased significantly (P < .05) during the course of our study, because of the introduction of automatic exposure control, low kilovoltage, and high pitch techniques. All studies were of diagnostic quality. CONCLUSION SSDE is a valid dose measure in children undergoing chest CT angiography over a wide range of scanner platforms, techniques, and patient sizes, and it may be used to model breast dose and to document the results of dose reduction strategies.
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Ivanov VK, Kashcheev VV, Chekin SY, Menyaylo AN, Pryakhin EA, Tsyb AF, Mettler FA. Estimation of risk from medical radiation exposure based on effective and organ dose: how much difference is there? RADIATION PROTECTION DOSIMETRY 2013; 155:317-328. [PMID: 23390145 DOI: 10.1093/rpd/nct008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The authors compare radiation risks of potential cancer following diagnostic radiation exposure evaluated with the use of organ and effective doses. Lifetime attributable risk values of CT scanning are estimated with the use of ICRP (Publication 103) risk models and Russian national medical statistics data. For populations under the age of 50, the risk evaluated using organ doses usually differs from that using effective doses by <30 %. In older populations, the difference can be up to a factor of 3. Calculated values of lifetime attributable cancer risk for particular organs are presented as well.
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Affiliation(s)
- V K Ivanov
- Federal State Institution Medical Radiological Research Center of the Russian Ministry of Health and Social Development, 4 Korolyov Str., Obninsk, Kaluga Region 249036, Russia.
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Xia W, Yin XR, Wu JT, Wu HT. Comparative study of DTS and CT in the skeletal trauma imaging diagnosis evaluation and radiation dose. Eur J Radiol 2013; 82:e76-80. [DOI: 10.1016/j.ejrad.2012.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 09/19/2012] [Accepted: 09/21/2012] [Indexed: 11/25/2022]
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Sugimoto N, Aoyama T, Koyama S, Yamauchi-Kawaura C, Fujii K. Comparison of radiation doses between newborns and 6-y-old children undergoing head, chest and abdominal CT examinations: a phantom study. RADIATION PROTECTION DOSIMETRY 2013; 153:85-91. [PMID: 22645383 DOI: 10.1093/rpd/ncs085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Radiation doses in paediatric computed tomography (CT) were investigated for various types of recent CT scanners with newborn and 6-y-old phantoms in which silicon-photodiode dosemeters were implanted at various organ positions. In the head, chest and abdominal CT for the newborn phantom, doses for organs within the scan region were 21-40, 3-8 and 3-12 mGy, respectively. The corresponding doses for the child phantom were 20-37, 2-11 and 4-17 mGy, respectively. In the head, chest and abdominal CT, the effective doses were respectively 2.1-3.3, 2.0-6.0 and 2.2-10.0 mSv for the newborn, and 1.0-2.0, 1.2-6.6 and 2.9-11.8 mSv for the child. Radiation doses for the newborn were at the same levels as those for the child, excepting effective doses in head CT for the newborn, which were 1.8 times higher than those for the child.
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Affiliation(s)
- Naruto Sugimoto
- Graduate school of Medicine, Nagoya University, Daikominami, Higashi-ku, Nagoya, Japan.
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31
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Tricarico F, Hlavacek AM, Schoepf UJ, Ebersberger U, Nance JW, Vliegenthart R, Cho YJ, Spears JR, Secchi F, Savino G, Marano R, Schoenberg SO, Bonomo L, Apfaltrer P. Cardiovascular CT angiography in neonates and children: Image quality and potential for radiation dose reduction with iterative image reconstruction techniques. Eur Radiol 2012. [DOI: 10.1007/s00330-012-2734-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Contribution to normal tissue dose from concomitant radiation for two common kV-CBCT systems and one MVCT system used in radiotherapy. Radiother Oncol 2012; 105:139-44. [DOI: 10.1016/j.radonc.2012.04.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 03/29/2012] [Accepted: 04/03/2012] [Indexed: 11/19/2022]
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Kawasaki T, Aoyama T, Yamauchi-Kawaura C, Fujii K, Koyama S. Organ dose and effective dose estimation in paediatric chest radiographic examinations by using pin silicon photodiode dosemeters. RADIATION PROTECTION DOSIMETRY 2012; 154:314-319. [PMID: 23019596 DOI: 10.1093/rpd/ncs251] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Organ and effective doses during paediatric chest radiographic examination were investigated for various tube voltages between 60 and 110 kV at a constant milliampere-second value and focus-to-film distance by using an in-phantom dose measuring system and a Monte Carlo (MC) simulation software (PCXMC), where the former was composed of 32 photodiode dosemeters embedded in various tissue and organ sites within a 6-y-old child anthropomorphic phantom. Lung doses obtained ranged from 0.010 to 0.066 mGy and effective doses from 0.004 to 0.025 mSv, where these doses varied by a factor of 6 with the change in the tube voltage. Effective doses obtained using the MC simulation software agreed with those obtained using the dose measuring system within 23 %, revealing the usefulness of PCXMC software for evaluating effective doses. The present study would provide helpful dose data for the selection of technical parameters in paediatric chest radiography in Japan.
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Affiliation(s)
- Toshio Kawasaki
- Department of Radiological Technology, Kanagawa Children's Medical Center, Mutsukawa 2-138-4, Minami-ku, Yokohama 232-8555, Japan.
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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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35
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Value of multidetector computed tomography for the radiologic grading of sacroiliitis in ankylosing spondylitis. Rheumatol Int 2012; 33:1005-11. [PMID: 22865054 DOI: 10.1007/s00296-012-2450-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 07/03/2012] [Indexed: 10/28/2022]
Abstract
The objective of this study is to investigate the value of multidetector computed tomography (MDCT) in the assessment of sacroiliitis in patients with established ankylosing spondylitis (AS). Paired plain radiographs and MDCT images of the 330 sacroiliac (SI) joints in 165 patients with definite or probable ankylosing spondylitis were analyzed for sacroiliitis. Sacroiliitis on plain radiographs were graded on a scale of 0-4 according to the modified New York (NY) criteria. For grading of sacroiliitis by MDCT, modified NY criteria were revised for MDCT application introducing the concept of quantification. The relationship between sacroiliitis grades by plain radiography and MDCT was analyzed by two radiologists, blinded for all clinical data. Of the 330 SI joints assessed, there was agreement between the sacroiliitis grading by plain radiography and MDCT in 73 (22.1 %) SI joints. Sacroiliitis grade by MDCT was higher in 250 (75.8 %) SI joints and lower in 7 (2.1 %) SI joints than that by plain radiography. Using the MDCT, 83.6 % of patients met the modified NY radiologic criteria for the classification of AS, compared with 58.2 % of the patients by plain radiography. Twenty-six percent of the patients, who did not meet the modified NY criteria for the classification of AS by plain radiography, met the criteria by MDCT. Disease durations in patients with grade 2 and grade 3 sacroiliitis were significantly shorter in patients evaluated by MDCT compared with plain radiography. MDCT is a useful imaging method that can be applied to the initial diagnosis of the AS, and by better visualization of SI joint changes, it can be used to predict the progress of the disease.
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McArthur C, Baxter GM. Current and potential renal applications of contrast-enhanced ultrasound. Clin Radiol 2012; 67:909-22. [PMID: 22464920 DOI: 10.1016/j.crad.2012.01.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 01/14/2012] [Accepted: 01/25/2012] [Indexed: 12/18/2022]
Abstract
The combination of microbubble technology and complementary ultrasound techniques has resulted in the development of contrast-enhanced ultrasound (CEUS) and, although initial clinical applications largely focussed on the liver, these are now becoming more diverse. With regard to the kidney, it is a safe, well-tolerated, and reproducible technique, and in selected cases, can obviate the need for computed tomography or magnetic resonance imaging. A clear advantage is the absence of nephrotoxicity. With respect to the current and potential renal applications, it is a useful technique in the evaluation of pseudotumours, acute pyelonephritis, renal tumours, cystic lesions, vascular insults, and renal transplantation. It may also be of value for monitoring the kidney following anti-angiogenic treatment or nephron-sparing interventional techniques for renal tumours. Assessment of microvascular perfusion using time-intensity curves is also likely to have further far-reaching applications in the kidney as well as other organs.
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Affiliation(s)
- C McArthur
- Department of Radiology, Western Infirmary, Glasgow, UK
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Lin MT, Wang JK, Chen YS, Lee WJ, Chiu HH, Chen CA, Chiu SN, Wu ET, Lu CW, Huang SC, Chen SJ, Chiu IS, Chang CI, Wu MH. Detection of pulmonary arterial morphology in tetralogy of Fallot with pulmonary atresia by computed tomography: 12 years of experience. Eur J Pediatr 2012; 171:579-86. [PMID: 22083156 DOI: 10.1007/s00431-011-1621-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 10/27/2011] [Indexed: 10/15/2022]
Abstract
UNLABELLED Our aim was to evaluate the feasibility of using computed tomography (CT) to define the pulmonary artery anatomy in patients with tetralogy of Fallot and pulmonary atresia (TOF-PA). We retrospectively reviewed 110 patients with TOF-PA between 1995 and 2008. Those who received cardiac catheterization and surgery within 3 months of their CT examinations were enrolled. Based on Dr. Somerville's classification, the pulmonary arterial pattern was determined, including identifiable pulmonary trunk (type I), the presence of both left and right pulmonary arteries without trunk (II), only left or right pulmonary artery present (III), and absent intrapericardial pulmonary arteries (IV). The accuracy of both imaging modalities was evaluated with operation findings as the golden standard. The effective radiation doses and adverse events were also recorded. In the 64 eligible patients (median age, 23 months), CT and catheterization demonstrated accurate pulmonary arterial morphology in 60 (60/64) and 53 (53/64) TOF-PA patients, respectively. Thirty-two of 35 type I patients were correctly identified by CT, whereas 26 were correctly identified by catheterization (p = 0.03). Of the 20 type II TOF-PA patients, 19 were diagnosed by CT, whereas 18 were diagnosed by catheterization. CT and catheterization both successfully defined six type III and three type IV patients. The median calculated radiation doses caused by CT and catheterization were 4.5 and 5.6 mSv, respectively (p > 0.05). CONCLUSIONS For patients with TOF-PA, CT could accurately delineate pulmonary arterial morphology with the same level of accuracy as cardiac catheterization. Therefore, CT can be considered a reasonable diagnostic alternative for such patients.
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Affiliation(s)
- Ming-Tai Lin
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
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Bernier MO, Rehel JL, Brisse HJ, Wu-Zhou X, Caer-Lorho S, Jacob S, Chateil JF, Aubert B, Laurier D. Radiation exposure from CT in early childhood: a French large-scale multicentre study. Br J Radiol 2012; 85:53-60. [PMID: 22190749 DOI: 10.1259/bjr/90758403] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES The increasing use of CT scans in the paediatric population raises the question of a possible health impact of ionising radiation exposure associated with CT scans. The aim of this study was to describe the pattern of CT use in early childhood. METHODS In 14 major French paediatric radiology departments, children undergoing at least 1 CT scan before age 5, between 2000 and 2006, were included. For each examination, absorbed organ doses were calculated. RESULTS 43% of the 27 362 children in the cohort were aged less than 1 year during their first exposure, with 9% being aged less than 1 month. The mean number of examinations per child was 1.6 (range 1-43). The examinations included: head in 63% of the cases, chest in 21%, abdomen and pelvis in 8% and others in 8%. Brain and eye lenses received the highest cumulative doses from head examinations, with mean organ dose values of 22 mGy (maximum 1107 mGy) and 26 mGy (maximum 1392 mGy), respectively. The mean cumulative effective dose was 3.2 mSv (range 0.1-189 mSv). CONCLUSION CT scan exposure in childhood is responsible for relatively high doses to radiosensitive organs. The rather large dose range according to the protocols used requires their optimisation. The cohort follow-up will study the risk of long-term radiation-induced cancer.
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Affiliation(s)
- M-O Bernier
- Epidemiology Department, Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses, France.
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Fujii K, Akahane K, Miyazaki O, Horiuchi T, Shimada A, Nagmatsu H, Yamauchi M, Yamauchi-Kawaura C, Kawasaki T. Evaluation of organ doses in CT examinations with an infant anthropomorphic phantom. RADIATION PROTECTION DOSIMETRY 2011; 147:151-155. [PMID: 21743079 DOI: 10.1093/rpd/ncr289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of this study is to evaluate organ doses in infant CT examinations with multi-detector row CT scanners. Radiation doses were measured with radiophotoluminescence glass dosemeters set in various organ positions within a 1-y-old child anthropomorphic phantom and organ doses were evaluated from the measurement values. Doses for tissues or organs within the scan range were 28-36 mGy in an infant head CT, 3-11 mGy in a chest CT, 5-11 mGy in an abdominal-pelvic CT and 2-14 mGy in a cardiac CT. The doses varied by the differences in the types of CT scanners and scan parameters used at each medical facility. Compared with those for children of various ages, the doses in an infant CT protocol were found to be similar to or slightly smaller than those in a paediatric CT for 5- or 6-y-old children.
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Affiliation(s)
- K Fujii
- Department of Radiation, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba, Japan.
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Brenner DJ, Shuryak I, Einstein AJ. Impact of reduced patient life expectancy on potential cancer risks from radiologic imaging. Radiology 2011; 261:193-8. [PMID: 21771956 DOI: 10.1148/radiol.11102452] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE To quantify the effect of reduced life expectancy on cancer risk by comparing estimated lifetime risks of lung cancer attributable to radiation from commonly used computed tomographic (CT) examinations in patients with and those without cancer or cardiac disease. MATERIALS AND METHODS With the use of clinically determined life tables, reductions in radiation-attributable lung cancer risks were estimated for coronary CT angiographic examinations in patients with multivessel coronary artery disease who underwent coronary artery bypass graft (CABG) surgery and for surveillance CT examinations in patients treated for colon cancer. Statistical uncertainties were estimated for the risk ratios in patients who underwent CABG surgery and patients with colon cancer versus the general population. RESULTS Patients with decreased life expectancy had decreased radiation-associated cancer risks. For example, for a 70-year-old patient with colon cancer, the estimated reduction in lifetime radiation-associated lung cancer risk was approximately 92% for stage IV disease, versus 8% for stage 0 or I disease. For a patient who had been treated with CABG surgery, the estimated reduction in lifetime radiation-associated lung cancer risk was approximately 57% for a 55-year-old patient, versus 12% for a 75-year-old patient. CONCLUSION The importance of radiation exposure in determining optimal imaging usage is much reduced for patients with markedly reduced life expectancies: Imaging justification and optimization criteria for patients with substantially reduced life expectancies should not necessarily be the same as for those with normal life expectancies.
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Affiliation(s)
- David J Brenner
- Center for Radiological Research and Department of Medicine and Radiology, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY 10032, USA.
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Dougeni E, Faulkner K, Panayiotakis G. A review of patient dose and optimisation methods in adult and paediatric CT scanning. Eur J Radiol 2011; 81:e665-83. [PMID: 21684099 DOI: 10.1016/j.ejrad.2011.05.025] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 12/14/2022]
Abstract
An increasing number of publications and international reports on computed tomography (CT) have addressed important issues on optimised imaging practice and patient dose. This is partially due to recent technological developments as well as to the striking rise in the number of CT scans being requested. CT imaging has extended its role to newer applications, such as cardiac CT, CT colonography, angiography and urology. The proportion of paediatric patients undergoing CT scans has also increased. The published scientific literature was reviewed to collect information regarding effective dose levels during the most common CT examinations in adults and paediatrics. Large dose variations were observed (up to 32-fold) with some individual sites exceeding the recommended dose reference levels, indicating a large potential to reduce dose. Current estimates on radiation-related cancer risks are alarming. CT doses account for about 70% of collective dose in the UK and are amongst the highest in diagnostic radiology, however the majority of physicians underestimate the risk, demonstrating a decreased level of awareness. Exposure parameters are not always adjusted appropriately to the clinical question or to patient size, especially for children. Dose reduction techniques, such as tube-current modulation, low-tube voltage protocols, prospective echocardiography-triggered coronary angiography and iterative reconstruction algorithms can substantially decrease doses. An overview of optimisation studies is provided. The justification principle is discussed along with tools that assist clinicians in the decision-making process. There is the potential to eliminate clinically non-indicated CT scans by replacing them with alternative examinations especially for children or patients receiving multiple CT scans.
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Affiliation(s)
- E Dougeni
- Imaging Physics and Radiation Safety Section, Regional Medical Physics Department, Freeman Hospital, Freeman Road, Newcastle Upon Tyne NE7 7DN, UK.
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Prospective gating with 320-MDCT angiography: effect of volume scan length on radiation dose. AJR Am J Roentgenol 2011; 196:407-11. [PMID: 21257894 DOI: 10.2214/ajr.10.4903] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the relation between radiation dose reduction and volume scan length for prospectively ECG-gated 320-MDCT angiography in the diagnosis of coronary artery disease. MATERIALS AND METHODS MDCT with prospective ECG gating was performed at one of the three volume scan lengths depending on heart length. Of 175 patients, 95 (55%; body mass index, 29 ± 5.9; mean heart rate, 59 ± 7 beats/min) underwent scanning at 160 mm; 46 (26%; body mass index, 30 ± 4.1; mean heart rate, 56 ± 5.74 beats/min) at 140 mm; and 34 (19%; body mass index, 30 ± 3.71; mean heart rate, 58 ± 3.96 beats/min) at 120 mm. RESULTS The median radiation doses were 6.5 mSv (95% CI, 6.03-7.2 mSv) for the 95 patients who underwent scanning at a volume scan length of 160 mm, 4.33 mSv (95% CI, 4.06-6.62 mSv) for the 46 patients who underwent scanning at 140 mm, and 3.47 mSv (95% CI, 3.15-3.62 mSv) for the 34 patients who underwent scanning at 120 mm. The reduction in scan length from 160 to 140 mm represented a reduction in scan length of 12.5% and the reduction to 120 mm a reduction of 25%. The median radiation dose was reduced 33% when volume scan length was changed to 140 mm and 47% when the length was changed to 120 mm. CONCLUSION Dose optimization remains an important concern in cardiac CT, and for 320-MDCT angiography, substantial dose reduction can be achieved by reducing volume scan length so that it is in concert with the patient's heart length.
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Yamauchi-Kawara C, Fujii K, Aoyama T, Yamauchi M, Koyama S. Radiation dose evaluation in multidetector-row CT imaging for acute stroke with an anthropomorphic phantom. Br J Radiol 2011; 83:1029-41. [PMID: 21088088 DOI: 10.1259/bjr/52267127] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This study evaluated radiation dose and dose reduction in CT imaging for acute stroke. Radiation doses in three types of CT imaging (i.e. non-contrast-enhanced CT, CT perfusion (CTP) and CT angiography (CTA)) were measured with an in-phantom dosimetry system for 4-, 16- and 64-detector CT scanners in 5 hospitals. To examine the relationship between image quality and radiation dose in CTA, image contrast-to-noise ratio was evaluated. Doses to the brain, lens, salivary glands and local skin obtained with scan protocols in routine use were: 42-71 mGy, 30-88 mGy, 3.9-7.3 mGy and 40-97 mGy in non-contrast-enhanced CT; 41-75 mGy, 9.9-10 mGy, 1.5-2.1 mGy and 107-143 mGy in CTP; and 8.2-55 mGy, 26-69 mGy, 2.0-73 mGy and 32-72 mGy in CTA. For the combination of these CT examinations, on average a patient would receive 236 mGy for the maximum local skin dose and 4.2 mSv for the effective dose evaluated by the International Commission on Radiological Protection (ICRP) 103. Effective doses in CTP in this study were less than those obtained with representative protocols of Western countries. Average effective doses in each CT examination were not more than 1.5 mSv. The use of reduced kV and a narrow scan range would be effective in dose reduction of CTA and CTP, and intermittent scanning would be essential in CTP. Although lens and maximum local skin doses were far less than the thresholds for deterministic effects, since radiation risks would be increased in repeated CT examinations, efforts should be devoted to dose reduction in stroke CT examinations.
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Koyama S, Aoyama T, Oda N, Yamauchi-Kawaura C. Radiation dose evaluation in tomosynthesis and C-arm cone-beam CT examinations with an anthropomorphic phantom. Med Phys 2010; 37:4298-306. [PMID: 20879590 DOI: 10.1118/1.3465045] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The objective of this study was to evaluate organ dose and the effective dose to patients undergoing tomosynthesis (TS) and C-arm cone-beam computed tomography (CBCT) examinations and to compare the doses to those in multidetector CT (MDCT) scans. METHODS Patient doses were measured with small sized silicon-photodiode dosimeters, 48 in number, which were implanted at various tissue and organ positions within an anthropomorphic phantom. Output signals from photodiode dosimeters were read out on a personal computer, from which organ and effective doses were computed. The doses in head, chest, abdomen, and hip-joint TS, and in head and abdomen C-arm CBCT were evaluated for routine protocols on Shimadzu TS and C-arm CBCT systems, and the doses in MDCT with the same scan regions as in TS and CBCT were on Toshiba 64-detector-row CT scanners. RESULTS In TS examination of the head, chest, abdomen, and hip-joint, organ doses for organs within scan ranges were 1-4 mGy, and effective doses were 0.07 mSv for the head scan and around 1 mSv for other scans. In C-arm CBCT examinations of the head and abdomen, organ doses within scan range were 2-37 mGy, and effective doses were 1.2 mSv for the head scan and 4-5 mSv for abdominal scans. Effective doses in TS examinations were approximately a factor of 10 lower, while the doses in CBCT examinations were nearly the same level, compared to the doses in the corresponding MDCT examinations. CONCLUSIONS TS examinations with low doses and excellent resolutions in coronal images compared to recent MDCT would widely be used in tomographic examinations of the chest, abdomen, pelvis, skeletal-joints, and knee instead of MDCT examinations with significantly high doses. Since patient dose in C-arm CBCT was nearly the same level as that in recent MDCT, the same consideration for high radiation dose would be required for the use of CBCT.
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Affiliation(s)
- Shuji Koyama
- Department of Radiological Technology, School of Health Sciences, Nagoya University, Japan.
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Seguchi S, Aoyama T, Koyama S, Fujii K, Yamauchi-Kawaura C. Patient radiation dose in prospectively gated axial CT coronary angiography and retrospectively gated helical technique with a 320-detector row CT scanner. Med Phys 2010; 37:5579-85. [DOI: 10.1118/1.3496985] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Sinnott B, Ron E, Schneider AB. Exposing the thyroid to radiation: a review of its current extent, risks, and implications. Endocr Rev 2010; 31:756-73. [PMID: 20650861 PMCID: PMC3365850 DOI: 10.1210/er.2010-0003] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 06/04/2010] [Indexed: 12/26/2022]
Abstract
Radiation exposure of the thyroid at a young age is a recognized risk factor for the development of differentiated thyroid cancer lasting for four decades and probably for a lifetime after exposure. Medical radiation exposure, however, occurs frequently, including among the pediatric population, which is especially sensitive to the effects of radiation. In the past, the treatment of benign medical conditions with external radiation represented the most significant thyroid radiation exposures. Today, diagnostic medical radiation represents the largest source of man-made radiation exposure. Radiation exposure related to the use of computerized tomography is rising exponentially, particularly in the pediatric population. There is direct epidemiological evidence of a small but significant increased risk of cancer at radiation doses equivalent to computerized tomography doses used today. Paralleling the increasing use of medical radiation is an increase in the incidence of papillary thyroid cancer. At present, it is unclear how much of this increase is related to increased detection of subclinical disease from the increased utilization of ultrasonography and fine-needle aspiration, how much is due to a true increase in thyroid cancer, and how much, if any, can be ascribed to medical radiation exposure. Fortunately, the amount of radiation exposure from medical sources can be reduced. In this article we review the sources of thyroid radiation exposure, radiation risks to the thyroid gland, strategies for reducing radiation exposure to the thyroid, and ways that endocrinologists can participate in this effort. Finally, we provide some suggestions for future research directions.
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Affiliation(s)
- Bridget Sinnott
- Section of Endocrinology, Diabetes, and Metabolism, College of Medicine, University of Illinois at Chicago, 1819 West Polk Street (MC 640), Chicago, Illinois 60612, USA
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Hirata T, Inoue K, Shigemori S, Matsuzaki M, Inatomi K. [Estimation of exposure dose on MDCT examination--the measurement of organ dose and effective dose by anthropomorphic phantom]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2010; 66:901-10. [PMID: 20953106 DOI: 10.6009/jjrt.66.901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In order to evaluate the exposure dose in CT examinations, we measured the tissue and organ doses by test site in 4-row, 16-row, and 64-row multi detector CT by using an anthropomorphic phantom and fluorescent glass dosimeters. Furthermore, we calculated the effective dose by using the tissue weighting factor recommended by the ICRP in 2007. The effective dose in the head and neck examinations was 1.4-3.1 mSv, whereas the maximum skin dose was 278.9 mGy in head perfusion CT. The effective dose in examinations of the body trunk was 10.1-35.2 mSv. In addition, the organ dose and skin dose in the scanning range was similar to the CTDI(vol) in head and neck examinations, while it was higher than the CTDI(vol) in examinations of the body trunk. The exposure dose of patients undergoing CT is high in comparison to other radiological examinations. As a result, due to consecutive examinations, an absorbed dose of more than 100 mGy is possible. A future problem therefore remains how to lower the overall exposure dose with the introduction of new radiographic diagnostic modalities, such as phase scan or coronary CT angiography.
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Yamauchi-Kawaura C, Fujii K, Aoyama T, Koyama S, Yamauchi M. Radiation dose evaluation in head and neck MDCT examinations with a 6-year-old child anthropomorphic phantom. Pediatr Radiol 2010; 40:1206-14. [PMID: 20066408 DOI: 10.1007/s00247-009-1495-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 11/04/2009] [Accepted: 11/06/2009] [Indexed: 01/21/2023]
Abstract
BACKGROUND CT examinations of the head and neck are the most commonly performed CT studies in children, raising concern about radiation dose and their risks to children. OBJECTIVE The purpose of this study was to clarify radiation dose levels for children of 6 years of age undergoing head and neck multidetector CT (MDCT) examinations. MATERIALS AND METHODS Radiation doses were measured with small-sized silicon-photodiode dosimeters that were implanted at various tissue and organ positions within a standard 6-year-old anthropomorphic phantom. Organ and effective doses of brain CT were evaluated for 19 protocols in nine hospitals on various (2-320 detector rows) MDCT scanners. RESULTS The maximum value of mean organ dose in brain CT was 34.3 mGy for brain. Maximum values of mean doses for the radiosensitive lens and thyroid were 32.7 mGy for lens in brain CT and 17.2 mGy for thyroid in neck CT. seventy-fifth percentile of effective dose distribution in brain CT was approximately the same as the diagnostic reference level (DRL) in the 2003 UK survey. CONCLUSION The results of this study would encourage revision of MDCT protocols in pediatric head and neck CT examinations for dose reduction and protocol standardization.
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Affiliation(s)
- Chiyo Yamauchi-Kawaura
- School of Health Sciences, Nagoya University, Daikominami, Higashi-ku, Nagoya 461-8673, Japan.
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Radiation doses to ERCP patients are significantly lower with experienced endoscopists. Gastrointest Endosc 2010; 72:58-65. [PMID: 20421102 PMCID: PMC2906113 DOI: 10.1016/j.gie.2009.12.060] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 12/29/2009] [Indexed: 12/22/2022]
Abstract
BACKGROUND Patients undergoing ERCP receive nontrivial doses of radiation, which may increase their risk of developing cancer, especially young patients. Radiation doses to patients during ERCP correlate closely with fluoroscopy time. OBJECTIVE The aim of this study was to determine whether endoscopist experience is associated with fluoroscopy time. DESIGN Retrospective analysis of a prospectively collected database. SETTING Data from 69 providers from 6 countries. PATIENTS 9,052 entries of patients undergoing ERCP. MAIN OUTCOME MEASUREMENTS Percent difference in fluoroscopy time associated with endoscopist experience and fellow involvement. RESULTS For procedure types that require less fluoroscopy time, compared with endoscopists who performed > 200 ERCPs in the preceding year, endoscopists who performed <100 and 100 to 200 ERCPs had 104% (95% confidence interval [CI], 85%-124%) and 27% (95% CI, 20%-35%) increases in fluoroscopy time, respectively. Every 10 years of experience was associated with a 21% decrease in fluoroscopy time (95% CI, 19%-24%). For fluoroscopy-intense procedures, compared with endoscopists who performed >200 ERCPs in the preceding year, endoscopists who performed <100 and 100 to 200 ERCPs had 59% (95% CI, 39%-82%) and 11% (95% CI, 3%-20%) increases in fluoroscopy time, respectively. Every 10 years of experience was associated with a 20% decrease in fluoroscopy time (95% CI, 18%-24%). LIMITATIONS Database used is a voluntary reporting system, which may not be generalizable. Data is self-reported and was not verified for accuracy. CONCLUSIONS Fluoroscopy time is shorter when ERCP is performed by endoscopists with more years of performing ERCP and a greater number of ERCPs in the preceding year. These findings may have important ramifications for radiation-induced cancer risk.
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Coronary CT angiography with low radiation dose. Int J Cardiovasc Imaging 2010; 26 Suppl 1:17-25. [PMID: 20058080 DOI: 10.1007/s10554-009-9576-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 12/21/2009] [Indexed: 02/07/2023]
Abstract
With the introduction of 64-slice CT and dual-source CT technology, coronary CT angiography(CCTA) has emerged as a useful diagnostic imaging modality for the noninvasive assessment of coronary heart disease. Recently, the risks associated with ionizing radiation on CT have raised serious concerns.The main concern of exposure to ionizing radiation is the potential risk of cancer. CCTA involves much higher radiation dose with the advances in the spatial and temporal resolution of cardiac CT. Currently,various dose-saving algorithms, such as ECG (electrocardiography)-based dose modulation, reduced tube voltage, and prospective ECG gating, high-pitch helical scanning are available to lower radiation exposure during cardiac CT. Therefore, careful selection of CT scanning protocols is needed to keep the radiation exposure 'as low as reasonably achievable (ALARA)'. In this review we will discuss the radiation dose safety issues, the measurement of radiation dose and current use of dose-saving techniques in CCTA.
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