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Robatjazi M, Moayed M, Baghani HR, Molazadeh M, Shomoossi N. Evaluation of organ dose using size-specific dose estimation (SSDE) and related cancer risk due to chest CT scan during the COVID-19 pandemic. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2024; 63:27-37. [PMID: 38185693 DOI: 10.1007/s00411-023-01056-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 12/08/2023] [Indexed: 01/09/2024]
Abstract
This study aimed to estimate lung and breast doses for individual patients using the size-specific dose estimate (SSDE) method, as well as calculating effective doses, in patients who underwent chest CT scans during the COVID-19 pandemic. Cancer risk incidence was estimated using excess relative risk (ERR), excess absolute risk (EAR), and lifetime attributable risk (LAR) models from the Biological Effects of Ionizing Radiation Report VII (BEIR-VII). Data from about 570 patients who underwent CT scans for COVID-19 screening were utilized for this study. Using the header of the CT images in a Python script, SSDE and effective dose were calculated for each patient. The SSDE obtained by water equivalent effective diameter (wSSDE) was considered as lung and breast dose, and applied in organ-specific cancer risk estimation. The mean wSSDE value for females (13.3 mGy) was slightly higher than that for males (13.1 mGy), but the difference was not statistically significant (P value = 0.41). No significant differences were observed between males and females in terms of calculated EAR and ERR for lung cancer at 5 and 30 years after exposure (P value = 0.47, 0.46, respectively). Similarly, there was no significant difference in lung cancer LAR values between females and males (P value = 0.48). The results also indicated a decrease in LAR values for both lung and breast cancers with increasing exposure age. In accordance with the ALARA (as low as reasonably achievable) principle, it is important for medical staff and the general public to consider the benefits of CT imaging in detecting such infections. Additionally, imaging medical physicists and CT scan experts should optimize imaging protocols and strike a balance between image quality for detecting abnormalities and radiation dose, all while adhering to the ALARA principle.
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Affiliation(s)
- Mostafa Robatjazi
- Department of Medical Physics and Radiological Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran
- Non-Communicable Disease Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Mahdis Moayed
- Department of Medical Physics and Radiological Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | | | - Mikaeil Molazadeh
- Department of Medical Physics, Tabriz University of Medical Sciences, Tabriz, Iran
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Alrehily F, Alshamrani AF. Estimation of radiation dose associated with bone SPECT/CT and establishing local diagnostic reference levels using size-specific dose estimate. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2023. [DOI: 10.1016/j.jrras.2023.100527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Establishment of national diagnostic dose reference levels (DRLs) for routine computed tomography examinations in Jordan. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2023. [DOI: 10.2478/pjmpe-2023-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Abstract
Background: Dose reference levels (DRLs) are used as indicators as well as guidance for dose optimization and to ensure justification of appropriate dose for a given clinical indication. The main aims of this study were to establish local DRLs for each CT imaging protocol as a reference point to evaluate the radiation dose indices and to compare our DRLs with those established in other countries and against the internationally reported guidelines.
Materials and methods: 2000 CT dose reports of different adult imaging protocols from January 2021 until April 2022 were collected retrospectively at different hospitals in Jordan. Data were collected from CT scans that were performed using different types and models of CT scanners and included four adult non-enhanced, helical CT imaging protocols; Head, Chest, Abdomen-Pelvis, and Chest-Abdomen-Pelvis.
Results: The average doses of CTDIvol, DLP, and effective dose were (65.11 mGy, 1232.71 mGy·cm, 2.83 mSv) for the head scan, (16.6 mGy, 586.6 mGy·cm, 8.21 mSv) for the chest scan, (17.91 mGy, 929.9 mGy·cm, 13.9 mSv) for the abdomen-pelvis scan, and (19.3 mGy, 1152 mGy·cm, 17.25 mSv) for the chest-abdomen-pelvis scan. In comparison with results from different international studies, DLP values measured in the present study were lower for the chest-abdomen-pelvis and abdomen-pelvis CT scans, and higher for the head CT and chest CT scans.
Conclusions: It is very important that each country establishes its own DRLs and compares them with those reported by other countries, especially the developed ones. It is also important that these levels are regularly updated.
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Anim-Sampong S, Ohene-Botwe B, Adom EB, Tagoe SNA. Dose optimization of adult head computed tomography examination in an academic hospital in Ghana. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Fukunaga M, Matsubara K, Yamaguchi Y. [Organ and Effective Doses Using Automation Organ Dose Estimation Software for Lung Cancer Screening Using Low-dose Computed Tomography]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2022; 78:1176-1186. [PMID: 36058849 DOI: 10.6009/jjrt.2022-1205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
PURPOSE The purpose of this study was to evaluate the differences in the organ doses and the effective doses using three types of automated organ dose estimation software for low-dose computed tomography (CT) screening for lung cancer and to evaluate the correlations between each dose and size-specific dose estimates (SSDEs). METHODS Seventy-two adults who underwent low-dose CT screening for lung cancer were included, and the organ doses and the effective doses were calculated using each of automated organ dose estimation software. We evaluated differences between software for the organ doses and the effective doses and the correlations between each dose and SSDEs. RESULTS Differences in organ doses and effective doses were observed among the software. The organ doses showed a strong correlation (r=0.833-0.995) with SSDEs for organs within the scan range. The effective doses showed a strong correlation (r=0.830-0.970) with SSDEs, although there were significant differences among the software. CONCLUSION Although the organ doses and the effective doses differed between software, it may be possible to estimate them from SSDEs by using linear regression equations.
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Affiliation(s)
- Masaaki Fukunaga
- Department of Radiological Technology, Kurashiki Central Hospital
| | - Kosuke Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
| | - Yuki Yamaguchi
- Department of Radiological Technology, Kurashiki Central Hospital
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Abdulkadir MK, Shuaib IL, Achuthan A, Nasirudin RA, Samsudin AHZ, Osman ND. ESTIMATION OF PEDIATRIC DOSE DESCRIPTORS ADAPTED TO INDIVIDUAL SPECIFIC SIZE FROM CT EXAMINATIONS. RADIATION PROTECTION DOSIMETRY 2022; 198:1292-1302. [PMID: 35896148 DOI: 10.1093/rpd/ncac163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 06/15/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Clinical challenges in pediatrics dose estimation by the displayed computed tomography (CT) dose indices may lead to inaccuracy, and thus size-specific dose estimate (SSDE) is introduced for better-personalized dose estimation. This study aims to estimate pediatric dose adapted to specific size. This retrospective study involved pediatric population aged 0-12 y. SSDE was derived from scanner reported volume CT dose index (CTDIvol), based on individual effective diameter (Deff) with corresponding size correction factors. The correlations of Deff with other associated factors such as age, exposure setting, CTDIvol and SSDE were also studied. The average Deff of Malaysian pediatric was smaller than reference phantom size (confidence interval, CI = 0.28, mean = 14.79) and (CI = 0.51, mean = 16.33) for head and abdomen, respectively. These have led to underestimation of pediatric dose as SSDE was higher than displayed CTDIvol. The percentage differences were statistically significant (p < .001) ranged from 0 to 17% and 37 to 60% for head and abdominal CT, respectively. In conclusion, the clinical implementation of SSDE in pediatric CT imaging is highly relevant to reduce radiation risk.
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Affiliation(s)
- Muhammad Kabir Abdulkadir
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, 13200 Penang, Malaysia
- Department of Medical Radiography, Faculty of Basic Clinical Sciences, University of Ilorin, 240213 Ilorin, Nigeria
| | - Ibrahim Lutfi Shuaib
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, 13200 Penang, Malaysia
| | - Anusha Achuthan
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, 13200 Penang, Malaysia
- School of Computer Science, Universiti Sains Malaysia, Minden, 11800 Penang, Malaysia
| | - Radin A Nasirudin
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, 13200 Penang, Malaysia
| | - Ahmad Hadif Zaidin Samsudin
- Department of Radiology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Noor Diyana Osman
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, 13200 Penang, Malaysia
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Patient dose estimation in CT examination using dose conversion coefficient method and CT -expo software. HEALTH AND TECHNOLOGY 2022. [DOI: 10.1007/s12553-022-00683-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Poor practice and governance in Lebanese national diagnostic reference levels of adult head and body computed tomography: A nationwide study. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Tabari A, Li X, Yang K, Liu B, Gee MS, Westra SJ. Patient-level dose monitoring in computed tomography: tracking cumulative dose from multiple multi-sequence exams with tube current modulation in children. Pediatr Radiol 2021; 51:2498-2506. [PMID: 34532817 DOI: 10.1007/s00247-021-05160-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 06/08/2021] [Accepted: 07/23/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND In children exposed to multiple computed tomography (CT) exams, performed with varying z-axis coverage and often with tube current modulation, it is inaccurate to add volume CT dose index (CTDIvol) and size-specific dose estimate (SSDE) to obtain cumulative dose values. OBJECTIVE To introduce the patient-size-specific z-axis dose profile and its dose line integral (DLI) as new dose metrics, and to use them to compare cumulative dose calculations against conventional measures. MATERIALS AND METHODS In all children with 2 or more abdominal-pelvic CT scans performed from 2013 through 2019, we retrospectively recorded all series kV, z-axis tube current profile, CTDIvol, dose-length product (DLP) and calculated SSDE. We constructed dose profiles as a function of z-axis location for each series. One author identified the z-axis location of the superior mesenteric artery origin on each series obtained to align the dose profiles for construction of each patient's cumulative profile. We performed pair-wise comparisons between the peak dose of the cumulative patient dose profile and ΣSSDE, and between ΣDLI and ΣDLP. RESULTS We recorded dose data in 143 series obtained in 48 children, ages 0-2 years (n=15) and 8-16 years (n=33): ΣSSDE 12.7±6.7 and peak dose 15.1±8.1 mGy, ΣDLP 278±194 and ΣDLI 550±292 mGy·cm. Peak dose exceeded ΣSSDE by 20.6% (interquartile range [IQR]: 9.9-26.4%, P<0.001), and ΣDLI exceeded ΣDLP by 114% (IQR: 86.5-147.0%, P<0.001). CONCLUSION Our methodology represents a novel approach for evaluating radiation exposure in recurring pediatric abdominal CT examinations, both at the individual and population levels. Under a wide range of patient variables and acquisition conditions, graphic depiction of the cumulative z-axis dose profile across and beyond scan ranges, including the peak dose of the profile, provides a better tool for cumulative dose documentation than simple summations of SSDE. ΣDLI is advantageous in characterizing overall energy absorption over ΣDLP, which significantly underestimated this in all children.
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Affiliation(s)
- Azadeh Tabari
- Department of Radiology, Massachusetts General Hospital, 34 Fruit St., Boston, MA, 02114, USA
| | - Xinhua Li
- Department of Radiology, Massachusetts General Hospital, 34 Fruit St., Boston, MA, 02114, USA
| | - Kai Yang
- Department of Radiology, Massachusetts General Hospital, 34 Fruit St., Boston, MA, 02114, USA
| | - Bob Liu
- Department of Radiology, Massachusetts General Hospital, 34 Fruit St., Boston, MA, 02114, USA
| | - Michael S Gee
- Department of Radiology, Massachusetts General Hospital, 34 Fruit St., Boston, MA, 02114, USA
| | - Sjirk J Westra
- Department of Radiology, Massachusetts General Hospital, 34 Fruit St., Boston, MA, 02114, USA.
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Wills DJ, Neville-Towle J, Podadera J, Johnson KA. Computed Tomographic Evaluation of the Accuracy of Minimally Invasive Sacroiliac Screw Fixation in Cats. Vet Comp Orthop Traumatol 2021; 35:119-127. [PMID: 34847579 DOI: 10.1055/s-0041-1736648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVES The aim of this study was to report the use of computed tomography (CT) for postoperative evaluation of the accuracy of sacroiliac reduction and minimally invasive screw fixation in a series of five cats. MATERIALS AND METHODS Medical records between January 2016 and March 2017 of cats presenting to the author's institution were reviewed. Included were cats that had undergone minimally invasive sacroiliac screw fixation with a complete medical record and pre- and postoperative radiographs. Screw size was obtained from the medical records. CT images were acquired prospectively and evaluated to assess joint reduction, relative screw size and screw positioning. RESULTS Six sacroiliac luxations and 6 screws were available. Fixation was achieved with either a 2.4 (n = 1) or 2.7 mm (n = 5), 316L stainless steel, cortical bone screw. Mean screw size as a proportion of sacral diameter was 47.7%. Sacroiliac reduction >90% in the craniocaudal plane and sacral screw purchase >60% of the sacral width were achieved in 3/5 cases. Mean dorsoventral screw angulation was 1.6 degrees (range: -9.7 to 11.7 degrees) and craniocaudal angulation was -4.5 degrees (range: -16.6 to 6.6 degrees). Complications included screw loosening in the one case of bilateral repair and penetration of the neural canal in one case which was not detected with postoperative radiographic evaluation. CLINICAL SIGNIFICANCE CT evaluation provides a useful method for the assessment of sacroiliac reduction and the accuracy of screw placement.
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Affiliation(s)
- Daniel J Wills
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Sydney, Australia
| | - Jack Neville-Towle
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Sydney, Australia
| | - Juan Podadera
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Sydney, Australia
| | - Kenneth A Johnson
- Faculty of Science, Sydney School of Veterinary Science, University of Sydney, Sydney, Australia
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Hrdy M, Mahesh M, Miller M, Klein B, Stewart D, Ryan LM. An Analysis of Computed Tomography-Related Radiation Exposure in Pediatric Trauma Patients. Pediatr Emerg Care 2021; 37:296-302. [PMID: 34038924 DOI: 10.1097/pec.0000000000002085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To compare radiation doses used for pediatric computed tomography (CT) scans at community-based referring facilities (RF) to those at a designated pediatric trauma center (PTC) to assess the consistency of radiation exposure. METHODS In this retrospective study, patients 0 to 18 years of age with CT imaging performed either at a RF or at a PTC from January 1, 2015, to January 5, 2016, were identified. Data about patients, CT radiation dose, and characteristics of the RFs were compared. RESULTS We identified 502 patients (156 RF, 346 PTC) with 281 head CTs (79 RF, 202 PTC) and 86 abdominal/pelvis CTs (28 RF, 58 PTC). The radiation dose (measured in mean dose-length product [DLP] ± 1 standard deviation) was significantly higher for RF scans compared with PTC scans (head, RF DLP = 545 ± 334 vs PTC DLP = 438 ± 186 (P < 0.001); abdomen/pelvis, RF DLP = 279 ± 160 vs PTC DLP = 181 ± 201 [P = 0.027]). There was a nonsignificant trend toward lower head CT radiation dosages at RFs with a dedicated pediatric emergency department compared with RFs without a pediatric emergency department. CONCLUSIONS Our data suggest that CT scans performed at RFs expose pediatric patients to significantly higher doses of radiation when compared with a PTC. These data support further study to identify factors associated with increased radiation and educational outreach to RFs.
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Affiliation(s)
| | | | | | | | - Dylan Stewart
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
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Fu W, Ria F, Segars WP, Choudhury KR, Wilson JM, Kapadia AJ, Samei E. Patient-Informed Organ Dose Estimation in Clinical CT: Implementation and Effective Dose Assessment in 1048 Clinical Patients. AJR Am J Roentgenol 2021; 216:824-834. [PMID: 33474986 PMCID: PMC8018383 DOI: 10.2214/ajr.19.22482] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE. The purpose of this study is to comprehensively implement a patient-informed organ dose monitoring framework for clinical CT and compare the effective dose (ED) according to the patient-informed organ dose with ED according to the dose-length product (DLP) in 1048 patients. MATERIALS AND METHODS. Organ doses for a given examination are computed by matching the topogram to a computational phantom from a library of anthropomorphic phantoms and scaling the fixed tube current dose coefficients by the examination volume CT dose index (CTDIvol) and the tube-current modulation using a previously validated convolution-based technique. In this study, the library was expanded to 58 adult, 56 pediatric, five pregnant, and 12 International Commission on Radiological Protection (ICRP) reference models, and the technique was extended to include multiple protocols, a bias correction, and uncertainty estimates. The method was implemented in a clinical monitoring system to estimate organ dose and organ dose-based ED for 647 abdomen-pelvis and 401 chest examinations, which were compared with DLP-based ED using a t test. RESULTS. For the majority of the organs, the maximum errors in organ dose estimation were 18% and 8%, averaged across all protocols, without and with bias correction, respectively. For the patient examinations, DLP-based ED was significantly different from organ dose-based ED by as much as 190.9% and 234.7% for chest and abdomen-pelvis scans, respectively (mean, 9.0% and 24.3%). The differences were statistically significant (p < .001) and exhibited overestimation for larger-sized patients and underestimation for smaller-sized patients. CONCLUSION. A patient-informed organ dose estimation framework was comprehensively implemented applicable to clinical imaging of adult, pediatric, and pregnant patients. Compared with organ dose-based ED, DLP-based ED may overestimate effective dose for larger-sized patients and underestimate it for smaller-sized patients.
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Affiliation(s)
- Wanyi Fu
- Department of Radiology, Duke University, 2424 Erwin Rd, Ste 302, Durham, NC 27705
- Department of Electrical and Computer Engineering, Duke University, Durham, NC
- Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, NC
| | - Francesco Ria
- Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, NC
- Clinical Imaging Physics Group, Duke University Health System, Durham, NC
| | - William Paul Segars
- Department of Radiology, Duke University, 2424 Erwin Rd, Ste 302, Durham, NC 27705
- Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, NC
- Medical Physics Graduate Program, Duke University, Durham, NC
- Department of Biomedical Engineering, Duke University, Durham, NC
| | | | - Joshua M Wilson
- Clinical Imaging Physics Group, Duke University Health System, Durham, NC
- Medical Physics Graduate Program, Duke University, Durham, NC
| | - Anuj J Kapadia
- Department of Radiology, Duke University, 2424 Erwin Rd, Ste 302, Durham, NC 27705
- Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, NC
- Medical Physics Graduate Program, Duke University, Durham, NC
- Department of Physics, Duke University, Durham, NC
| | - Ehsan Samei
- Department of Radiology, Duke University, 2424 Erwin Rd, Ste 302, Durham, NC 27705
- Department of Electrical and Computer Engineering, Duke University, Durham, NC
- Carl E. Ravin Advanced Imaging Laboratories, Duke University, Durham, NC
- Clinical Imaging Physics Group, Duke University Health System, Durham, NC
- Medical Physics Graduate Program, Duke University, Durham, NC
- Department of Biomedical Engineering, Duke University, Durham, NC
- Department of Physics, Duke University, Durham, NC
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McLeavy CM, Chunara MH, Gravell RJ, Rauf A, Cushnie A, Staley Talbot C, Hawkins RM. The future of CT: deep learning reconstruction. Clin Radiol 2021; 76:407-415. [PMID: 33637310 DOI: 10.1016/j.crad.2021.01.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/14/2021] [Indexed: 12/23/2022]
Abstract
There have been substantial advances in computed tomography (CT) technology since its introduction in the 1970s. More recently, these advances have focused on image reconstruction. Deep learning reconstruction (DLR) is the latest complex reconstruction algorithm to be introduced, which harnesses advances in artificial intelligence (AI) and affordable supercomputer technology to achieve the previously elusive triad of high image quality, low radiation dose, and fast reconstruction speeds. The dose reductions achieved with DLR are redefining ultra-low-dose into the realm of plain radiographs whilst maintaining image quality. This review aims to demonstrate the advantages of DLR over other reconstruction methods in terms of dose reduction and image quality in addition to being able to tailor protocols to specific clinical situations. DLR is the future of CT technology and should be considered when procuring new scanners.
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Affiliation(s)
- C M McLeavy
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - M H Chunara
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - R J Gravell
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - A Rauf
- Department of Urology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - A Cushnie
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - C Staley Talbot
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK
| | - R M Hawkins
- Department of Radiology, Leighton Hospital, Middlewich Road, Crewe, CW1 4QJ, UK.
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Azadbakht J, Khoramian D, Lajevardi ZS, Elikaii F, Aflatoonian AH, Farhood B, Najafi M, Bagheri H. A review on chest CT scanning parameters implemented in COVID-19 patients: bringing low-dose CT protocols into play. THE EGYPTIAN JOURNAL OF RADIOLOGY AND NUCLEAR MEDICINE 2021. [PMCID: PMC7784224 DOI: 10.1186/s43055-020-00400-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Abstract
Background
This study aims to review chest computed tomography (CT) scanning parameters which are utilized to evaluate patients for COVID-19-induced pneumonia. Also, some of radiation dose reduction techniques in CT would be mentioned, because using these techniques or low-dose protocol can decrease the radiation burden on the population.
Main body
Chest CT scan can play a key diagnostic role in COVID-19 patients. Additionally, it can be useful to monitor imaging changes during treatment. However, CT scan overuse during the COVID-19 pandemic raises concerns about radiation-induced adverse effects, both in patients and healthcare workers.
Conclusion
By evaluating the CT scanning parameters used in several studies, one can find the necessity for optimizing these parameters. It has been found that chest CT scan taken using low-dose CT protocol is a reliable diagnostic tool to detect COVID-19 pneumonia in daily practice. Moreover, the low-dose chest CT protocol results in a remarkable reduction (up to 89%) in the radiation dose compared to the standard-dose protocol, not lowering diagnostic accuracy of COVID-19-induced pneumonia in CT images. Therefore, its employment in the era of the COVID-19 pandemic is highly recommended.
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Inoue Y, Nagahara K, Kudo H, Itoh H. EFFECTS OF THE SCAN RANGE ON RADIATION DOSE IN THE COMPUTED TOMOGRAPHY COMPONENT OF ONCOLOGY POSITRON EMISSION TOMOGRAPHY/COMPUTED TOMOGRAPHY. RADIATION PROTECTION DOSIMETRY 2019; 185:1-6. [PMID: 30508127 DOI: 10.1093/rpd/ncy210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 10/06/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
We performed phantom experiments to investigate radiation dose in the computed tomography component of oncology positron emission tomography/computed tomography in relation to the scan range. Computed tomography images of an anthropomorphic whole-body phantom were obtained from the head top to the feet, from the head top to the proximal thigh or from the skull base to the proximal thigh. Automatic exposure control using the posteroanterior and lateral scout images offered reasonable tube current modulation corresponding to the body thickness. However, when the posteroanterior scout alone was used, unexpectedly high current was applied in the head and upper chest. When effective dose was calculated on a region-by-region basis, it did not differ greatly irrespective of the scan range. In contrary, when effective dose was estimated simply by multiplying the scanner-derived dose-length product by a single conversion factor, estimates increased definitely with the scan range, indicating severe overestimation in whole-body imaging.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Kitasato, Minami-ku, Sagamihara, Kanagawa, Japan
| | - Kazunori Nagahara
- Department of Radiology, Kitasato University Hospital, Kitasato, Minami-ku, Sagamihara, Kanagawa, Japan
| | - Hiroko Kudo
- Department of Radiology, Kitasato University Hospital, Kitasato, Minami-ku, Sagamihara, Kanagawa, Japan
| | - Hiroyasu Itoh
- Department of Radiology, Kitasato University Hospital, Kitasato, Minami-ku, Sagamihara, Kanagawa, Japan
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Rosendahl S, Büermann L, Borowski M, Kortesniemi M, Sundell VM, Kosunen A, Siiskonen T. CT beam dosimetric characterization procedure for personalized dosimetry. Phys Med Biol 2019; 64:075009. [PMID: 30856614 DOI: 10.1088/1361-6560/ab0e97] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Personalized dosimetry in computed tomography (CT) can be realized by a full Monte Carlo (MC) simulation of the scan procedure. Essential input data needed for the simulation are appropriate CT x-ray source models and a model of the patient's body which is based on the CT image. The purpose of this work is to develop comprehensive procedures for the determination of CT x-ray source models and their verification by comparison of calculated and measured dose distributions in physical phantoms. Mobile equipment together with customized software was developed and used for non-invasive determination of equivalent source models of CT scanners under clinical conditions. Standard and physical anthropomorphic CT dose phantoms equipped with real-time CT dose probes at five representative positions were scanned. The accumulated dose was measured during the scan at the five positions. ImpactMC, an MC-based CT dose software program, was used to simulate the scan. The necessary inputs were obtained from the scan parameters, from the equivalent source models and from the material-segmented CT images of the phantoms. 3D dose distributions in the phantoms were simulated and the dose values calculated at the five positions inside the phantom were compared to measured dose values. Initial results were obtained by means of a General Electric Optima CT 660 and a Toshiba (Canon) Aquilion ONE. In general, the measured and calculated dose values were within relative uncertainties that had been estimated to be less than 10%. The procedures developed were found to be viable and rapid. The procedures are applicable to any scanner type under clinical conditions without making use of the service mode with stationary x-ray tube position. Results show that the procedures are well suited for determining and verifying the equivalent source models needed for personalized CT dosimetry based on post-scan MC calculations.
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Affiliation(s)
- S Rosendahl
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
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Somasundaram E, Artz NS, Brady SL. Development and validation of an open source Monte Carlo dosimetry model for wide-beam CT scanners using Fluka. J Appl Clin Med Phys 2019; 20:132-147. [PMID: 30851155 PMCID: PMC6448170 DOI: 10.1002/acm2.12559] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 01/14/2019] [Accepted: 02/13/2019] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Development and validation of an open source Fluka-based Monte Carlo source model for diagnostic patient dose calculations. METHODS A framework to simulate a computed tomography (CT) scanner using Fluka Monte Carlo particle transport code was developed. The General Electric (GE) Revolution scanner with the large body filter and 120 kV tube potential was characterized using measurements. The model was validated on benchmark CT test problems and on dose measurements in computed tomography dose index (CTDI) and anthropomorphic phantoms. Axial and helical operation modes with provision for tube current modulation (TCM) were implemented. The particle simulations in Fluka were accelerated by executing them on a high-performance computing cluster. RESULTS The simulation results agreed to better than an average of 4% of the reference simulation results from the AAPM Report 195 test scenarios, namely: better than 2% for both test problems in case 4 using the PMMA phantom, and better than 5% of the reference result for 14 of 17 organs in case 5, and within 10% for the three remaining organs. The Fluka simulation results agreed to better than 2% of the air kerma measured in-air at isocenter of the GE Revolution scanner. The simulated air kerma in the center of the CTDI phantom overestimated the measurement by 7.5% and a correction factor was introduced to account for this. The simulated mean absorbed doses for a chest scan of the pediatric anthropomorphic phantom was completed in ~9 min and agreed to within the 95% CI for bone, soft tissue, and lung measurements made using MOSFET detectors for fixed current axial and helical scans as well as helical scan with TCM. CONCLUSION A Fluka-based Monte Carlo simulation model of axial and helical acquisition techniques using a wide-beam collimation CT scanner demonstrated good agreement between measured and simulated results for both fixed current and TCM in complex and simple geometries. Code and dataset will be made available at https://github.com/chezhia/FLUKA_CT.
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Affiliation(s)
- Elanchezhian Somasundaram
- Department of Diagnostic Imaging, St Jude Children's Research Hospital, Memphis, TN, USA.,Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Nathan S Artz
- Department of Diagnostic Imaging, St Jude Children's Research Hospital, Memphis, TN, USA
| | - Samuel L Brady
- Department of Diagnostic Imaging, St Jude Children's Research Hospital, Memphis, TN, USA.,Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Radiology, University of Cincinnati, Cincinnati, OH, USA
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Riccardi L, De Monte F, Cretti F, Pini S, Zucca S, Quattrocchi MG, Origgi D, del Vecchio A, Giordano C, Marini P, Lisciandro F, Trevisiol E, Zefiro D, Cutaia C, D’Ercole L, Gabusi M, Scaggion A, Paiusco M. Use of radiation dose index monitoring software in a multicenter environment for CT dose optimization. Radiol Med 2018; 123:944-951. [DOI: 10.1007/s11547-018-0925-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 07/25/2018] [Indexed: 11/29/2022]
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19
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Dual-source computed tomography for quantitative assessment of tracheobronchial anomaly from type IIA pulmonary artery sling in pediatric patients. Eur J Radiol 2018; 102:30-35. [DOI: 10.1016/j.ejrad.2018.02.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 02/22/2018] [Accepted: 02/26/2018] [Indexed: 11/23/2022]
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20
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Ultralow-Dose CT (REDUCTION Protocol) for Extremity Fracture Evaluation Is as Safe and Effective as Conventional CT: An Evaluation of Quality Outcomes. J Orthop Trauma 2018; 32:216-222. [PMID: 29401094 DOI: 10.1097/bot.0000000000001137] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES To assess clinical and hospital quality outcomes of patients receiving the previously reported Reduced Effective Dose Using Computed Tomography In Orthopaedic Injury (REDUCTION) imaging protocol. DESIGN Retrospective Chart review. SETTING Level I Trauma Center and affiliated Tertiary Care Hospital Center. PATIENTS/PARTICIPANTS Fifty patients who received this protocol for acute traumatic fracture evaluation and met the inclusion criteria were compared with a cohort of 50 patients matched for age and fracture type who previously received conventional CT scanning for acute traumatic fracture evaluation. INTERVENTION Reduced Effective Dose Using Computed Tomography In Orthopaedic Injury (REDUCTION) protocol for diagnostic fracture evaluation. MAIN OUTCOME MEASURES Estimated effective radiation doses were calculated and compared using Digital Imaging and Communications in Medicine (DICOM) information from all included studies. Patient outcomes between groups were compared with time to fracture union as the primary outcome. Secondary outcome measures included the presence of complication defined as infection, malunion, nonunion, failure of nonoperative treatment, painful implants, and implant failure. Other secondary quality outcomes that were recorded included readmission within 30 days and hospital length of stay. Functional quality measures included joint range of motion. Statistical analyses were conducted to identify significant differences between cohorts (significance designated as P < 0.05). RESULTS Patient characteristics between cohorts were not significantly different with respect to age, sex, body mass index, comorbidities, injury mechanism, or injury location. Fractures of the elbow, hip, knee, and foot/ankle were evaluated. Mean clinical follow-up was 9.5 ± 4.9 months for the REDUCTION cohort and 12.4 ± 5.3 months for the conventional CT cohort. Mean estimated effective dose for all REDUCTION scans was 0.15 milliSieverts (mSv) as compared to 1.50 mSv for the conventional CT cohort (P = 0.037). Preoperative diagnosis was confirmed intraoperatively in 49/50 cases in the REDUCTION cohort compared with 48/50 cases in the conventional CT cohort (P = 0.79). Outcomes including time to union, range of motion, complications, readmission, treatment failure, reoperation, and length of stay were not significantly different between groups. CONCLUSIONS The REDUCTION protocol represents ultralow-dose CT developed for minimizing radiation exposure to patients presenting with traumatic fractures. This protocol resulted in a 10-fold reduction in radiation exposure. No difference in clinical or hospital quality outcomes was detected between patients who received this protocol as compared to those receiving automated dose CT. The REDUCTION protocol is a safe and effective method of performing CT for extremity fractures with significantly reduced radiation risk. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
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21
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Elmahdi A, Abuzaid MM, Babikir E, Sulieman A. Radiation Dose Associated with Multi-Detector 64-Slice Computed Tomography Brain Examinations in Khartoum State, Sudan. Pol J Radiol 2017; 82:603-606. [PMID: 29662592 PMCID: PMC5894015 DOI: 10.12659/pjr.902502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/14/2016] [Indexed: 12/18/2022] Open
Abstract
Background Radiation exposure due to computed tomography (CT) has become an important issue, as the number of CT examinations has been increasing worldwide. Radiation doses associated with CT are higher in comparison to other imaging procedures. CT-related radiation doses should be monitored and controlled in order to ensure reduction of radiation exposure and optimization of image quality. The aim of this study was to evaluate radiation doses in adult patient who underwent routine CT brain examinations, and to assess how CT scanning protocols affect patient doses in practice. Material/Methods A total of 118 patients underwent brain CT at two radiology departments equipped with 64-slice CT scanners, Khartoum, Sudan. Patient doses regarding weighted CT dose index (CTDIw) and dose length product (DLP) values were recorded. Quality control tests were performed for both scanners. Results The mean CTDIw values ranged from 62.9 to 65.8 mGy, DLP values ranged from 1003.7 to 1192.5 mGy, and the effective dose varied from 2.4 to 3.7 mSv. Conclusions Patient doses in this study was higher compared to previous research, suggesting that patients exposed to unnecessary radiation. Therefore, optimization of radiation doses with the use of specified imaging protocols, well-documented indications for CT, training of technicians, and quality control programs will reduce the necessary radiation doses. Establishment of the diagnostic reference level is recommended for further dose reduction.
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Affiliation(s)
- Ali Elmahdi
- Radiation Safety Institute, Sudan Atomic Energy Commission, Khartoum, Sudan
| | - Mohamed M Abuzaid
- Department of Medical Diagnostic Imaging, University of Sharjah, Sharjah, United Arab Emirates
| | - Esameldeen Babikir
- Department of Radiological Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Abdelmoneim Sulieman
- Department of Radiology and Medical Imaging, Prince Sattam bin Abdulaziz University, Alkharj, Saudi Arabia
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22
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Yang MX, Yang ZG, Zhang Y, Shi K, Xu HY, Diao KY, Guo YK. Dual-source Computed Tomography for Evaluating Pulmonary Artery and Aorta in Pediatric Patients with Single Ventricle. Sci Rep 2017; 7:13398. [PMID: 29042577 PMCID: PMC5645343 DOI: 10.1038/s41598-017-11809-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/29/2017] [Indexed: 02/05/2023] Open
Abstract
To explore the accuracy of main pulmonary artery (MPA) and ascending aorta (AAO) image evaluation in pediatric patients with single ventricle (SV) by comparing dual-source computed tomography (DSCT) with echocardiography. Thirty-one children with SV were retrospectively enrolled. The stenosis, dilation, and location of MPA and AAO were independently evaluated by DSCT and echocardiography. The accompanying arterial malformations were also assessed by DSCT. For 17 patients undergoing cardiac catheterization, the DSCT-based diameters of MPA and AAO were correlated with their pressures as measured by catheterization. Referring to the surgical and catheterization findings, DSCT had better diagnostic performance in detecting the stenosis, dilation, and location of MPA and AAO with higher sensitivity than echocardiography (sensitivity, MPA: 88.0% vs. 80.0%, AAO: 100% vs. 66.7%, great arteries location: 95.7% vs. 95.2%). The correlations between diameters of MPA and AAO with their pressures were 0.399 (p = 0.04) and 0.611 (p = 0.01), respectively. In addition, DSCT detected 23 cases with patent ductus arteriosus, 26 systemic-to-pulmonary collaterals, 9 branch pulmonary distortions, and 4 coronary artery anomalies. DSCT is reliable for assessing the anatomic features of pulmonary artery and aorta in SV children, and provides comprehensive information for surgical strategy-making.
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Affiliation(s)
- Meng-Xi Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Radiology, West China Hospital, Sichuan University, Chengdu, China.,Department of Radiology, Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Zhi-Gang Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China. .,Department of Radiology, West China Hospital, Sichuan University, Chengdu, China.
| | - Yi Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China.,Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Ke Shi
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Hua-Yan Xu
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Kai-Yue Diao
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Ying-Kun Guo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China. .,Department of Radiology, Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, China.
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Fahey FH, Goodkind A, MacDougall RD, Oberg L, Ziniel SI, Cappock R, Callahan MJ, Kwatra N, Treves ST, Voss SD. Operational and Dosimetric Aspects of Pediatric PET/CT. J Nucl Med 2017; 58:1360-1366. [PMID: 28687601 DOI: 10.2967/jnumed.116.182899] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/05/2017] [Indexed: 01/04/2023] Open
Abstract
No consistent guidelines exist for the acquisition of a CT scan as part of pediatric PET/CT. Given that children may be more vulnerable to the effects of ionizing radiation, it is necessary to develop methods that provide diagnostic-quality imaging when needed, in the shortest time and with the lowest patient radiation exposure. This article describes the basics of CT dosimetry and PET/CT acquisition in children. We describe the variability in pediatric PET/CT techniques, based on a survey of 19 PET/CT pediatric institutions in North America. The results of the survey demonstrated that, although most institutions used automatic tube current modulation, there remained a large variation of practice, on the order of a factor of 2-3, across sites, pointing to the need for guidelines. We introduce the approach developed at our institution for using a multiseries PET/CT acquisition technique that combines diagnostic-quality CT in the essential portion of the field of view and a low-dose technique to image the remainder of the body. This approach leads to a reduction in radiation dose to the patient while combining the PET and the diagnostic CT into a single acquisition. The standardization of pediatric PET/CT provides an opportunity for a reduction in the radiation dose to these patients while maintaining an appropriate level of diagnostic image quality.
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Affiliation(s)
- Frederic H Fahey
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts .,Department of Radiology, Harvard Medical School, Boston, Massachusetts
| | - Alison Goodkind
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts
| | - Robert D MacDougall
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts
| | - Leah Oberg
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts
| | - Sonja I Ziniel
- Section of Pediatric Hospital Medicine, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado; and
| | - Richard Cappock
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts
| | - Michael J Callahan
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.,Department of Radiology, Harvard Medical School, Boston, Massachusetts
| | - Neha Kwatra
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.,Department of Radiology, Harvard Medical School, Boston, Massachusetts
| | - S Ted Treves
- Department of Radiology, Harvard Medical School, Boston, Massachusetts.,Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Stephan D Voss
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.,Department of Radiology, Harvard Medical School, Boston, Massachusetts
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Hui PKT, Goo HW, Du J, Ip JJK, Kanzaki S, Kim YJ, Kritsaneepaiboon S, Lilyasari O, Siripornpitak S. Asian consortium on radiation dose of pediatric cardiac CT (ASCI-REDCARD). Pediatr Radiol 2017; 47:899-910. [PMID: 28435986 DOI: 10.1007/s00247-017-3847-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 01/17/2017] [Accepted: 03/22/2017] [Indexed: 12/22/2022]
Abstract
BACKGROUND With incremental utilization of pediatric cardiac CT in congenital heart disease, it is imperative to define its current radiation dose levels in clinical practice in order to help imagers optimize CT protocols, particularly in Asia and other developing countries where CT physicists are not readily available. OBJECTIVE To evaluate current radiation dose levels and influencing factors in cardiac CT in children with congenital heart disease in Asia by conducting a retrospective multi-center, multi-vendor study. MATERIALS AND METHODS We included 1,043 pediatric cardiac CT examinations performed in 8 centers between January 2014 and December 2014 to evaluate congenital heart disease. In five weight groups, we calculated radiation dose metrics including volume CT dose index, size-specific dose estimate, dose-length product and effective dose. Age at CT exam, gender, tube voltage, scan mode, CT indication and image reconstruction algorithm were analyzed to learn whether they influenced CT radiation dose. RESULTS Volume CT dose index, size-specific dose estimate, dose-length product and effective dose of pediatric cardiac CT showed variations in the range of 4.3-23.8 mGy, 4.9-17.6 mGy, 55.8-501.3 mGy∙cm and 1.5-3.2 mSv, respectively, within five weight groups. Gender, tube voltage, scan mode and cardiac function assessment significantly influenced CT radiation dose. CONCLUSION This multi-center, multi-vendor study demonstrated variations in radiation dose metrics of pediatric cardiac CT reflecting current practice in Asia. Gender, tube voltage, scan mode and cardiac function assessment should be considered as essential radiation dose-influencing factors in developing optimal pediatric cardiac CT protocols.
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Affiliation(s)
- Peter K T Hui
- Department of Radiology, Hong Kong Baptist Hospital, Hong Kong, SAR, China
| | - Hyun Woo Goo
- Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 138-736, South Korea.
| | - Jing Du
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Janice J K Ip
- Department of Radiology, Queen Mary Hospital, Hong Kong, SAR, China
| | - Suzu Kanzaki
- Department of Radiology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Young Jin Kim
- Department of Radiology, Yonsei University, Shinchon Severance Hospital, Seoul, South Korea
| | - Supika Kritsaneepaiboon
- Department of Radiology, Songklanagarind Hospital, Prince of Songkla University, Hat Yai, Thailand
| | - Oktavia Lilyasari
- Department of Cardiology, University of Indonesia, National Cardiovascular Center Harapan Kita, Jakarta, Indonesia
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25
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Murphy DJ, Keraliya A, Himes N, Aghayev A, Blankstein R, Steigner ML. Quantification of radiation dose reduction by reducing z-axis coverage in 320-detector coronary CT angiography. Br J Radiol 2017; 90:20170252. [PMID: 28613933 DOI: 10.1259/bjr.20170252] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE To quantify the radiation dose reduction achievable by minimizing z-axis coverage in 320-detector coronary CT angiography (CCTA). METHODS We retrospectively reviewed 130 CCTAs performed on 320-detector CT that offers up to 16 cm z-axis coverage (adjustable in 2-cm increments), allowing complete coverage of the heart in a single gantry rotation. For each CT, we obtained the radiation dose [CT dose index and dose-length product (DLP)], measured the z-axis field of view and measured the craniocaudal cardiac size (distance from the left main coronary artery to the cardiac apex). We calculated the radiation dose savings achievable by reducing the z-axis coverage to the minimum necessary to cover the heart using 320 × 0.5-mm (maximum 16 cm) and 256 × 0.5-mm (maximum 12.8 cm) detector collimations. RESULTS Results are expressed as mean ± standard deviation. The mean craniocaudal cardiac size was 10.5 ± 1.0 cm, with 85% (n = 112) of CCTAs performed with 16 cm of z-axis coverage. The mean DLP was 417.6 ± 182.4 mGy cm, with the mean DLP saving achievable using the minimum z-axis coverage required to completely image the heart being 96.2 ± 47.4 mGy cm, an average dose reduction of 26.9 ± 7.0%. z-axis coverage of ≤12 cm was adequate for 92% and 12.8 cm for 98% of subjects. CONCLUSION Using the minimal z-axis coverage to adequately image the heart is a simple step that can reduce the DLP in 320-detector CCTA by approximately 27%. z-axis coverage of ≤12 cm is adequate for 92%, 12.8 cm for 98% and 14 cm for 100% of patients undergoing CCTA. Advances in knowledge: Reducing z-axis coverage in 320-detector CCTA can reduce DLP by approximately 27%.
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Affiliation(s)
- David J Murphy
- Cardiovascular Imaging Program, Departments of Radiology and Medicine (Cardiovascular Division), Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Abhishek Keraliya
- Cardiovascular Imaging Program, Departments of Radiology and Medicine (Cardiovascular Division), Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Nathan Himes
- Cardiovascular Imaging Program, Departments of Radiology and Medicine (Cardiovascular Division), Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Ayaz Aghayev
- Cardiovascular Imaging Program, Departments of Radiology and Medicine (Cardiovascular Division), Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Ron Blankstein
- Cardiovascular Imaging Program, Departments of Radiology and Medicine (Cardiovascular Division), Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Michael L Steigner
- Cardiovascular Imaging Program, Departments of Radiology and Medicine (Cardiovascular Division), Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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26
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How accurate is size-specific dose estimate in pediatric body CT examinations? Pediatr Radiol 2016; 46:1234-40. [PMID: 27053280 DOI: 10.1007/s00247-016-3604-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 02/01/2016] [Accepted: 03/01/2016] [Indexed: 10/22/2022]
Abstract
BACKGROUND Size-specific dose estimate is gaining increased acceptance as the preferred index of CT dose in children. However it was developed based on non-clinical data. OBJECTIVE To compare the accuracy of size-specific dose estimate (SSDE) based on geometric and body weight measures in pediatric chest and abdomen CT scans, versus the more accurate [Formula: see text] (mean SSDE based on water-equivalent diameter). MATERIALS AND METHODS We retrospectively identified 50 consecutive children (age <18 years) who underwent chest CT examination and 50 children who underwent abdomen CT. We measured anteroposterior diameter (DAP) and lateral diameter (DLAT) at the central slice (of scan length) of each patient and calculated DAP+LAT (anteroposterior diameter plus lateral diameter) and DED (effective diameter) for each patient. We calculated the following in each child: (1) SSDEs based on DAP, DLAT, DAP+LAT, DED, and body weight, and (2) SSDE based on software calculation of mean water-equivalent diameter ([Formula: see text] adopted standard within our study). We used intraclass correlation coefficient (ICC) and Bland-Altman analysis to compare agreement between the SSDEs and [Formula: see text]. RESULTS Gender and age distribution were similar between chest and abdomen CT groups; mean body weight was 37 kg for both groups, with ranges of 6-130 kg (chest) and 8-107 kg (abdomen). SSDEs had very strong agreement (ICC>0.9) with [Formula: see text]. SSDEs based on DLAT had 95% limits of agreement of up to 43% with [Formula: see text]. SSDEs based on other parameters (body weight, DAP, DAP+LAT, DED) had 95% limits of agreement of up to 25%. CONCLUSION Differences between SSDEs calculated using various indications of patient size (geometric indices and patient weight) and the more accurate [Formula: see text] calculated using proprietary software were generally small, with the possible exception for lateral diameter, and provide acceptable dose estimates for body CT in children.
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Sly PD, Wainwright CE. Diagnosis and early life risk factors for bronchiectasis in cystic fibrosis: a review. Expert Rev Respir Med 2016; 10:1003-10. [PMID: 27329819 DOI: 10.1080/17476348.2016.1204915] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Lung disease in cystic fibrosis begins in early life with neutrophil-dominated inflammation and infection, is progressive and results in structural lung damage characterised by bronchial dilation and bronchiectasis. Preventative strategies must be employed in early life but require a better understanding of how bronchiectasis develops. AREAS COVERED In this review we have addressed the diagnosis and early life risk factors for bronchiectasis in young children with cystic fibrosis. A systematic review was not performed and the literature reviewed was known to the authors. Expert commentary: Bronchiectasis represents a process of progressive dilatation and damage of airway walls and is traditionally considered to be irreversible. Diagnosis is primarily by detecting a bronchial:arterial ratio of >1 on chest CT scan. Lung volume has a greater influence on airway diameter than on arterial making control of lung volume during scanning critical. Early life risk factors for the onset and progression bronchiectasis include: severe cystic fibrosis genotype; neutrophilic inflammation with free neutrophil elastase activity in the lung; and pulmonary infection. Bronchiectasis develops in the majority of children before they reach school age despite the best current therapy. To prevent bronchiectasis novel therapies are going to have to be given to infants.
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Affiliation(s)
- Peter D Sly
- a Department of Respiratory and Sleep Medicine , Children's Health Queensland , Brisbane , Australia.,b Child Health Research Centre , The University of Queensland , Brisbane , Australia
| | - Claire E Wainwright
- a Department of Respiratory and Sleep Medicine , Children's Health Queensland , Brisbane , Australia.,b Child Health Research Centre , The University of Queensland , Brisbane , Australia
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Dual-source computed tomography for evaluating pulmonary artery in pediatric patients with cyanotic congenital heart disease: Comparison with transthoracic echocardiography. Eur J Radiol 2015; 85:187-192. [PMID: 26724664 DOI: 10.1016/j.ejrad.2015.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 10/08/2015] [Accepted: 11/02/2015] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate the quantitative accuracy of dual-source computed tomography (DSCT) on measurements of pulmonary artery in pediatric patients with cyanotic congenital heart diseases (CCHDs) when compared with transthoracic echocardiography (TTE). METHODS Thirty-five patients (mean age: 27.88 ± 28.27 months) with CCHDs underwent DSCT and TTE for evaluating the diameter of the main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA). Surgical measurements were obtained and served as the reference standard. The agreement was tested by linear regression analysis, Pearson's correlation coefficient, and Bland-Altman analysis. The intra- and extracardiac malformations were also observed. RESULTS There was a markedly positive correlation between DSCT and surgical measurements of the MPA, RPA, and LPA (r=0.95-0.97; all p<0.001), although the overestimation of the measurements of MPA, RPA, and LPA (bias 0.15 ± 0.95, 0.31 ± 0.63 and 0.35 ± 0.68 mm, respectively) was observed. However, there was a moderate correlation between TTE and surgical measurements of MPA, RPA, and LPA (r=0.61-0.84; all p<0.001), and the underestimation of the measurements of MPA, RPA, and LPA (bias-1.20 ± 1.69, -1.80 ± 1.77, and -1.50 ± 2.30 mm, respectively) was observed. In addition, DSCT was more efficient in finding associated malformations than TTE (40/40 vs. 33/40). CONCLUSIONS As a reliable, noninvasive and radiation-save imaging modality, DSCT can provide more accurate pulmonary artery measurements than TTE in cardiac surgical procedures.
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Brady SL, Shulkin BL. Ultralow dose computed tomography attenuation correction for pediatric PET CT using adaptive statistical iterative reconstruction. Med Phys 2015; 42:558-66. [PMID: 25652476 DOI: 10.1118/1.4905045] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop ultralow dose computed tomography (CT) attenuation correction (CTAC) acquisition protocols for pediatric positron emission tomography CT (PET CT). METHODS A GE Discovery 690 PET CT hybrid scanner was used to investigate the change to quantitative PET and CT measurements when operated at ultralow doses (10-35 mA s). CT quantitation: noise, low-contrast resolution, and CT numbers for 11 tissue substitutes were analyzed in-phantom. CT quantitation was analyzed to a reduction of 90% volume computed tomography dose index (0.39/3.64; mGy) from baseline. To minimize noise infiltration, 100% adaptive statistical iterative reconstruction (ASiR) was used for CT reconstruction. PET images were reconstructed with the lower-dose CTAC iterations and analyzed for: maximum body weight standardized uptake value (SUVbw) of various diameter targets (range 8-37 mm), background uniformity, and spatial resolution. Radiation dose and CTAC noise magnitude were compared for 140 patient examinations (76 post-ASiR implementation) to determine relative dose reduction and noise control. RESULTS CT numbers were constant to within 10% from the nondose reduced CTAC image for 90% dose reduction. No change in SUVbw, background percent uniformity, or spatial resolution for PET images reconstructed with CTAC protocols was found down to 90% dose reduction. Patient population effective dose analysis demonstrated relative CTAC dose reductions between 62% and 86% (3.2/8.3-0.9/6.2). Noise magnitude in dose-reduced patient images increased but was not statistically different from predose-reduced patient images. CONCLUSIONS Using ASiR allowed for aggressive reduction in CT dose with no change in PET reconstructed images while maintaining sufficient image quality for colocalization of hybrid CT anatomy and PET radioisotope uptake.
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Affiliation(s)
- Samuel L Brady
- Division of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Barry L Shulkin
- Nuclear Medicine and Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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JOURNAL CLUB: A Comprehensive Risk Assessment Method for Pediatric Patients Undergoing Research Examinations Using Ionizing Radiation: How We Answered the Institutional Review Board. AJR Am J Roentgenol 2015; 204:W510-8. [DOI: 10.2214/ajr.14.13892] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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