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Lawson M, Berk K, Badawy M, Qi Y, Kuganesan A, Metcalfe P. Comparison of organ and effective dose estimations from different Monte Carlo simulation-based software methods in infant CT and comparison with direct phantom measurements. J Appl Clin Med Phys 2022; 23:e13625. [PMID: 35522240 PMCID: PMC9194989 DOI: 10.1002/acm2.13625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 03/09/2022] [Accepted: 04/11/2022] [Indexed: 11/30/2022] Open
Abstract
Purpose Computational dosimetry software is routinely used to evaluate the organ and effective doses from computed tomography (CT) examinations. Studies have shown a significant variation in dose estimates between software in adult cohorts, and few studies have evaluated software for pediatric dose estimates. This study aims to compare the primary organ and effective doses estimated by four commercially available CT dosimetry software to thermoluminescent dosimeter (TLD) measurements in a 1‐year‐old phantom. Methods One hundred fifteen calibrated LiF (Mg, Cu, P)‐TLD 100‐H chips were embedded within an anthropomorphic phantom representing a 1‐year‐old child at positions that matched the approximate location of organs within an infant. The phantom was scanned under three protocols, each with whole‐body coverage. The mean absorbed doses from 25 radiosensitive organs and skeletal tissues were determined from the TLD readings. Effective doses for each of the protocols were subsequently calculated using ICRP 103 formalism. Dose estimates by the four Monte Carlo–based dose calculation systems were determined and compared to the directly measured doses. Results Most organ doses determined by computation dosimetry software aligned to phantom measurements within 20%. Additionally, comparisons between effective doses are calculated using computational and direct measurement methods aligned within 20% across the three protocols. Significant variances were found in bone surface dose estimations among dosimetry methods, likely caused by differences in bone tissue modeling. Conclusion All four‐dosimetry software evaluated in this study provide adequate primary organ and effective dose estimations. Users should be aware, however, of the possible estimated uncertainty associated with each of the programs.
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Affiliation(s)
- Michael Lawson
- Monash Health Imaging, Monash Health, Clayton, Victoria, Australia.,Centre for Medical Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Kemal Berk
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Mohamed Badawy
- Monash Health Imaging, Monash Health, Clayton, Victoria, Australia.,Department of Medical Imaging and Radiation Sciences, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Yujin Qi
- Centre for Medical Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Ahilan Kuganesan
- Monash Health Imaging, Monash Health, Clayton, Victoria, Australia
| | - Peter Metcalfe
- Centre for Medical Radiation Physics, School of Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong, New South Wales, Australia
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Garzón WJ, Aldana DFA, Cassola VF. PATIENT-SPECIFIC ORGAN DOSES FROM PEDIATRIC HEAD CT EXAMINATIONS. RADIATION PROTECTION DOSIMETRY 2020; 191:1-8. [PMID: 32984906 DOI: 10.1093/rpd/ncaa126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/06/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
The aim of this work was to estimate patient's organ absorbed doses from pediatric helical head computed tomography (CT) examinations using the Size-Specific Dose Estimate (SSDE) methodology and to determine organ dose to SSDE conversion coefficients for clinical routine. Patient-specific organ and tissue absorbed doses from 139 Head CT scans performed in pediatric patients from 0 to 15 years old in a Public Hospital in Tunja, Colombia were estimated. The calculations were made through Monte Carlo simulations, based on patient-specific information, dosimetric CT quantities (CTDIvol, DLP) and age-specific computational human phantoms matched to patients on the basis of gender and size. SSDE showed to be a good quantity for estimate patient-specific organ doses from pediatric head CT examinations when appropriate phantom's attenuation-based size metrics are chosen to match for any patient size. Strong correlations between absorbed dose and SSDE were found for skin (R2 = 0.99), brain (R2 = 0.98) and eyes (R2 = 0.97), respectively. Besides, a good correlation between SSDE and absorbed dose to the red bone marrow (tissue extended outside the scan coverage) was observed (R2 = 0.94). SSDE-to-organ-dose conversion coefficients obtained in this study provide a practical way to estimate patient-specific organ head CT doses.
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Affiliation(s)
- W J Garzón
- Physics Department, Pedagogical and Technological University of Colombia, Avenida Central del Norte 39-115, 150003 Tunja, Colombia
| | - D F A Aldana
- Physics Department, Pedagogical and Technological University of Colombia, Avenida Central del Norte 39-115, 150003 Tunja, Colombia
| | - V F Cassola
- Department of Nuclear Energy, Federal University of Pernambuco, Avenida Professor Luiz Freire 1000 CEP 50740-540, Recife, Pernambuco, Brazil
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Perini AP, Santos WS, Neves LP, Belinato W, Caldas LV. Estimation of conversion coefficients for absorbed and effective doses for pediatric CT examinations in two different PET/CT scanners. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2018.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Belinato W, Silva RM, Perini AP, Neves LP, Santos CJ, Souza DN, Santos WS. Monte Carlo dosimetric evaluation in PET exams for patients with different BMI and heights. Radiat Phys Chem Oxf Engl 1993 2018. [DOI: 10.1016/j.radphyschem.2018.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pi Y, Liu T, Xu XG. DEVELOPMENT OF A SET OF MESH-BASED AND AGE-DEPENDENT CHINESE PHANTOMS AND APPLICATION FOR CT DOSE CALCULATIONS. RADIATION PROTECTION DOSIMETRY 2018; 179:370-382. [PMID: 29340629 DOI: 10.1093/rpd/ncx296] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 12/14/2017] [Indexed: 06/07/2023]
Abstract
Phantoms for organ dose calculations are essential in radiation protection dosimetry. This article describes the development of a set of mesh-based and age-dependent phantoms for Chinese populations using reference data recommended by the Chinese government and by the International Atomic Energy Agency (IAEA). Existing mesh-based RPI adult male (RPI-AM) and RPI adult female (RPI-AF) phantoms were deformed to form new phantoms according to anatomical data for the height and weight of Chinese individuals of 5 years old male, 5 years old female, 10 years old male, 10 years old female,15 years old male, 15 years old female, adult male and adult female-named USTC-5 M, USTC-5F, USTC-10M, USTC-10F, USTC-15M, USTC-15F, USTC-AM and USTC-AF, respectively. Following procedures to ensure the accuracy, more than 120 organs/tissues in each model were adjusted to match the Chinese reference parameters and the mass errors were within 0.5%. To demonstrate the usefulness, these new set of phantoms were combined with a fully validated model of the GE LightSpeed Pro 16 multi-detector computed tomography (MDCT) scanner and the GPU-based ARCHER Monte Carlo code to compute organ doses from CT examinations. Organ doses for adult models were then compared with the data of RPI-AM and RPI-AF under the same conditions. The absorbed doses and the effective doses of RPI phantoms are found to be lower than these of the USTC adult phantoms whose body sizes are smaller. Comparisons for the doses among different ages and genders were also made. It was found that teenagers receive more radiation doses than adults do. Such Chinese-specific phantoms are clearly better suited in organ dose studies for the Chinese individuals than phantoms designed for western populations. As already demonstrated, data derived from age-specific Chinese phantoms can help CT operators and designers to optimize image quality and doses.
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Affiliation(s)
- Yifei Pi
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui Province 230026, PR China
| | - Tianyu Liu
- Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - X George Xu
- School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui Province 230026, PR China
- Nuclear Engineering Program, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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Belinato W, Santos WS, Perini AP, Neves LP, Caldas LV, Souza DN. Estimate of S-values for children due to six positron emitting radionuclides used in PET examinations. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.02.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Jansen JTM, Shrimpton PC. Development of Monte Carlo simulations to provide scanner-specific organ dose coefficients for contemporary CT. Phys Med Biol 2016; 61:5356-77. [DOI: 10.1088/0031-9155/61/14/5356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Liorni I, Parazzini M, Varsier N, Hadjem A, Ravazzani P, Wiart J. Exposure assessment of one-year-old child to 3G tablet in uplink mode and to 3G femtocell in downlink mode using polynomial chaos decomposition. Phys Med Biol 2016; 61:3237-57. [PMID: 27027265 DOI: 10.1088/0031-9155/61/8/3237] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
So far, the assessment of the exposure of children, in the ages 0-2 years old, to relatively new radio-frequency (RF) technologies, such as tablets and femtocells, remains an open issue. This study aims to analyse the exposure of a one year-old child to these two sources, tablets and femtocells, operating in uplink (tablet) and downlink (femtocell) modes, respectively. In detail, a realistic model of an infant has been used to model separately the exposures due to (i) a 3G tablet emitting at the frequency of 1940 MHz (uplink mode) placed close to the body and (ii) a 3G femtocell emitting at 2100 MHz (downlink mode) placed at a distance of at least 1 m from the infant body. For both RF sources, the input power was set to 250 mW. The variability of the exposure due to the variation of the position of the RF sources with respect to the infant body has been studied by stochastic dosimetry, based on polynomial chaos to build surrogate models of both whole-body and tissue specific absorption rate (SAR), which makes it easy and quick to investigate the exposure in a full range of possible positions of the sources. The major outcomes of the study are: (1) the maximum values of the whole-body SAR (WB SAR) have been found to be 9.5 mW kg(-1) in uplink mode and 65 μW kg(-1) in downlink mode, i.e. within the limits of the ICNIRP 1998 Guidelines; (2) in both uplink and downlink mode the highest SAR values were approximately found in the same tissues, i.e. in the skin, eye and penis for the whole-tissue SAR and in the bone, skin and muscle for the peak SAR; (3) the change in the position of both the 3G tablet and the 3G femtocell significantly influences the infant exposure.
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Affiliation(s)
- I Liorni
- Istituto di Elettronica e di Ingegneria dell'Informazione e delle Telecomunicazioni IEIIT, Consiglio Nazionale delle Ricerche, Milano, Italy
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Dahdouh S, Varsier N, Nunez Ochoa MA, Wiart J, Peyman A, Bloch I. Infants and young children modeling method for numerical dosimetry studies: application to plane wave exposure. Phys Med Biol 2016; 61:1500-14. [PMID: 26815765 DOI: 10.1088/0031-9155/61/4/1500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Numerical dosimetry studies require the development of accurate numerical 3D models of the human body. This paper proposes a novel method for building 3D heterogeneous young children models combining results obtained from a semi-automatic multi-organ segmentation algorithm and an anatomy deformation method. The data consist of 3D magnetic resonance images, which are first segmented to obtain a set of initial tissues. A deformation procedure guided by the segmentation results is then developed in order to obtain five young children models ranging from the age of 5 to 37 months. By constraining the deformation of an older child model toward a younger one using segmentation results, we assure the anatomical realism of the models. Using the proposed framework, five models, containing thirteen tissues, are built. Three of these models are used in a prospective dosimetry study to analyze young child exposure to radiofrequency electromagnetic fields. The results lean to show the existence of a relationship between age and whole body exposure. The results also highlight the necessity to specifically study and develop measurements of child tissues dielectric properties.
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Affiliation(s)
- S Dahdouh
- LTCI, CNRS, Télécom ParisTech, Université Paris Saclay, Paris, France. Whist Lab, Paris, France
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Li C, Chen Z, Yang L, Lv B, Liu J, Varsier N, Hadjem A, Wiart J, Xie Y, Ma L, Wu T. Generation of infant anatomical models for evaluating electromagnetic field exposures. Bioelectromagnetics 2014; 36:10-26. [PMID: 25328088 DOI: 10.1002/bem.21868] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 07/06/2014] [Indexed: 11/06/2022]
Abstract
Realistic anatomical modeling is essential in analyzing human exposure to electromagnetic fields. Infants have significant physical and anatomical differences compared with other age groups. However, few realistic infant models are available. In this work, we developed one 12-month-old male whole body model and one 17-month-old male head model from magnetic resonance images. The whole body and head models contained 28 and 30 tissues, respectively, at spatial resolution of 1 mm × 1 mm × 1 mm. Fewer identified tissues in the whole body model were a result of the low original image quality induced by the fast imaging sequence. The anatomical and physical parameters of the models were validated against findings in published literature (e.g., a maximum deviation as 18% in tissue mass was observed compared with the data from International Commission on Radiological Protection). Several typical exposure scenarios were realized for numerical simulation. Dosimetric comparison with various adult and child anatomical models was conducted. Significant differences in the physical and anatomical features between adult and child models demonstrated the importance of creating realistic infant models. Current safety guidelines for infant exposure to radiofrequency electromagnetic fields may not be conservative.
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Affiliation(s)
- Congsheng Li
- China Academy of Telecommunication Research of Ministry of Industry and Information Technology, Beijing, China; College of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing, China
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