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Papadakis AE, Giannakaki V, Stratakis J, Myronakis M, Zaidi H, Damilakis J. Digital phantom versus patient-specific radiation dosimetry in adult routine thorax CT examinations. J Appl Clin Med Phys 2024; 25:e14389. [PMID: 38778565 PMCID: PMC11244670 DOI: 10.1002/acm2.14389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 04/09/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
PURPOSE The aim of this study was to compare the organ doses assessed through a digital phantom-based and a patient specific-based dosimetric tool in adult routine thorax computed tomography (CT) examinations with reference to physical dose measurements performed in anthropomorphic phantoms. METHODS Two Monte Carlo based dose calculation tools were used to assess organ doses in routine adult thorax CT examinations. These were a digital phantom-based dosimetry tool (NCICT, National Cancer Institute, USA) and a patient-specific individualized dosimetry tool (ImpactMC, CT Imaging GmbH, Germany). Digital phantoms and patients were classified in four groups according to their water equivalent diameter (Dw). Normalized to volume computed tomography dose index (CTDIvol), organ dose was assessed for lungs, esophagus, heart, breast, active bone marrow, and skin. Organ doses were compared to measurements performed using thermoluminescent detectors (TLDs) in two physical anthropomorphic phantoms that simulate the average adult individual as a male (Alderson Research Labs, USA) and as a female (ATOM Phantoms, USA). RESULTS The average percent difference of NCICT to TLD and ImpactMC to TLD dose measurements across all organs in both sexes was 13% and 6%, respectively. The average ± 1 standard deviation in dose values across all organs with NCICT, ImpactMC, and TLDs was ± 0.06 (mGy/mGy), ± 0.19 (mGy/mGy), and ± 0.13 (mGy/mGy), respectively. Organ doses decreased with increasing Dw in both NCICT and ImpactMC. CONCLUSION Organ doses estimated with ImpactMC were in closer agreement to TLDs compared to NCICT. This may be attributed to the inherent property of ImpactMC methodology to generate phantoms that resemble the realistic anatomy of the examined patient as opposed to NCICT methodology that incorporates an anatomical discrepancy between phantoms and patients.
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Affiliation(s)
- Antonios E. Papadakis
- University Hospital of HeraklionMedical Physics DepartmentStavrakia, HeraklionCreteGreece
| | - Vassiliki Giannakaki
- University Hospital of HeraklionMedical Physics DepartmentStavrakia, HeraklionCreteGreece
| | - John Stratakis
- University Hospital of HeraklionMedical Physics DepartmentStavrakia, HeraklionCreteGreece
| | - Marios Myronakis
- University Hospital of HeraklionMedical Physics DepartmentStavrakia, HeraklionCreteGreece
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular ImagingGeneva University HospitalGenevaSwitzerland
- Department of Nuclear Medicine and Molecular ImagingUniversity of GroningenUniversity Medical Center GroningenGroningenNetherlands
- Department of Nuclear MedicineUniversity of Southern DenmarkOdenseDenmark
- University Research and Innovation CenterObuda UniversityBudapestHungary
| | - John Damilakis
- University of Crete, Medical SchoolMedical Physics DepartmentStavrakia, HeraklionCreteGreece
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Lee C, Moroz B, Thome C, Gaudreau K, Emami P, Little MP. Reconstruction of organ doses for patients undergoing computed tomography examinations in Canada 1992-2019. RADIATION PROTECTION DOSIMETRY 2024; 200:379-386. [PMID: 38186237 PMCID: PMC10954068 DOI: 10.1093/rpd/ncad315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 10/31/2023] [Accepted: 11/30/2023] [Indexed: 01/09/2024]
Abstract
We derived the first comprehensive organ dose library for Canadian pediatric and adult patients who underwent computed tomography (CT) scans between 1992 and 2019 to support epidemiological analysis of radiation risk. We calculated organ absorbed doses for Canadian CT patients in two steps. First, we modeled Computed Tomography Dose Index (CTDI) values by patient age, scan body part, and scan year for the scan period between 1992 and 2019 using national survey data conducted in Canada and partially the United Kingdom survey data as surrogates. Second, we converted CTDI values to organ absorbed doses using a library of organ dose conversion coefficients built in an organ dose calculation program, the National Cancer Institute dosimetry system for CT. In result, we created a library of doses delivered to 33 organs and tissues by different patient ages and genders, scan body parts and scan years. In the scan period before 2000, the organs receiving the greatest dose in the head, chest and abdomen-pelvis scans were the active marrow (3.7-15.2 mGy), lungs (54.7-62.8 mGy) and colon (54.9-68.5 mGy), respectively. We observed organ doses reduced by 24% (pediatric head and torso scans, and adult head scans) and 55% (adult torso scans) after 2000. The organ dose library will be used to analyse the risk of radiation exposure from CT scans in the Canadian CT patient cohort.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, United States
| | - Brian Moroz
- Computing and Software Solutions for Science, LLC, Bethany Beach, DE, 19930, United States
| | - Christopher Thome
- Medical Sciences Division, NOSM University, Sudbury, ON, P3E 2C6, Canada
- School of Natural Sciences, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Katherine Gaudreau
- Medical Sciences Division, NOSM University, Sudbury, ON, P3E 2C6, Canada
| | - Pirouz Emami
- Department of Physics & Astronomy, McMaster University, Hamilton, ON, ON L8S 4L8, Canada
| | - Mark P Little
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, 20850, United States
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Aboyewa OB, Laternser C, Popescu A, Murphy N, Shah D, Monge MC, Rigsby CK, Golestanirad L, Webster G, Kim D. Cumulative radiation dose from medical imaging in paediatric congenital heart disease patients with epicardial cardiac implantable electronic devices. EUROPEAN HEART JOURNAL. IMAGING METHODS AND PRACTICE 2024; 2:qyae060. [PMID: 39045197 PMCID: PMC11251694 DOI: 10.1093/ehjimp/qyae060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/23/2024] [Indexed: 07/25/2024]
Abstract
Aims To determine whether paediatric congenital heart disease (CHD) patients with epicardial cardiac implantable electronic devices (CIEDs) receive high cumulative effective doses (CEDs) of ionizing radiation from medical imaging tests. Methods and results We compared 28 paediatric CHD patients with epicardial CIEDs (cases) against 40 patients with no CIED matched by age at operation, sex, surgical era, and CHD diagnosis (controls). We performed a retrospective review of radiation exposure from medical imaging exams between 2006 and 2022. Radiation dose from computed tomography (CT) and X-ray radiography was calculated using the National Cancer Institute Radiation Dosimetry Tool. We performed univariate analysis to compare the CED between the two groups. In the case subgroup, we convened experts' review to adjudicate the prevalence of CT exams that should have been performed with magnetic resonance imaging (MRI) in the absence of a CIED. Children (median age 2.5 years at implant) with CIEDs received significantly higher median CED compared with matched controls (6.90 vs. 1.72 mSv, P = 0.0018). In cases, expert adjudication showed that 80% of the CT exams would have been performed with MRI in the absence of a CIED. This resulted, on average, a five-fold increase in the effective dose (ED) from post-lead implant CTs. Conclusion Paediatric CHD patients with CIED received four times higher CED than matched controls. Improved access to medical imaging tests without ionizing radiation, such as MRI, could potentially reduce the ED in CIED patients by up to five times.
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Affiliation(s)
- Oluyemi B Aboyewa
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, E310, Evanston, IL 60208, USA
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Avenue Suite 1600, Chicago, IL 60611, USA
| | - Christina Laternser
- Division of Cardiology, Department of Pediatrics, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Andrada Popescu
- Department of Medical Imaging, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Nicole Murphy
- Department of Medical Imaging, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Dhaivat Shah
- Division of Cardiology, Department of Pediatrics, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Michael C Monge
- Division of Cardiovascular Surgery, Department of Surgery, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Cynthia K Rigsby
- Department of Medical Imaging, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Laleh Golestanirad
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, E310, Evanston, IL 60208, USA
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Avenue Suite 1600, Chicago, IL 60611, USA
| | - Gregory Webster
- Division of Cardiology, Department of Pediatrics, Ann & Robert H. Lurie Children’s Hospital, 225 E Chicago Avenue, Chicago, IL 60611, USA
| | - Daniel Kim
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, E310, Evanston, IL 60208, USA
- Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N. Michigan Avenue Suite 1600, Chicago, IL 60611, USA
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Akyea-Larbi KO, Hasford F, Inkoom S, Tetteh MA, Gyekye PK. Evaluation of organ and effective doses using anthropomorphic phantom: A comparison between experimental measurement and a commercial dose calculator. Radiography (Lond) 2024; 30:1-5. [PMID: 37864985 DOI: 10.1016/j.radi.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/23/2023]
Abstract
INTRODUCTION The aim of this study was to experimentally measure organ doses for computed tomography (CT) procedures using thermoluminescence dosimeters (TLDs) on a RANDO anthropomorphic phantom and verify the measured doses using CT-Expo software. METHODS The phantom was irradiated using clinical CT scan protocols routinely used for specific procedures in the radiology department. Fifty TLD chips were used in this study. The scanning parameters (kVp, mA, s) used to scan the phantom were used as input parameters for CT-Expo dose estimations. RESULTS The TLD measured organ doses varied between 3.97 mGy for the esophagus and 56.22 mGy for the brain. High doses were recorded in the brain (37.80-56.22 mGy) and the eye lens (29.94-36.16 mGy). Comparing the organ dose measurements between TLD and CT-Expo, the maximum organ dose difference was obtained for the eye lens. A comparison between the two methods for the other organs were all less than 32 %. The effective doses from the TLD measurements for the head, chest, and abdominopelvic CT examinations were 2.78, 6.67, and 17 mSv, respectively and CT-Expo were 2.20, 10.30, and 16.70 mSv, respectively. CONCLUSION The experimental and computational results are comparable, and the reliability of the TLD measurements and CT-Expo dose calculator has been proven. IMPLICATIONS FOR STUDY A reason for the difference in dose measurements between the two methods has been attributed to the dissimilarity in the organ position in the Rando anthropomorphic phantom and the standard mathematical phantom used by CT-Expo. The experimental and computational results have been found to be comparable.
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Affiliation(s)
- K O Akyea-Larbi
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana; Radiation Protection Institute, Ghana Atomic Energy Commission, Accra, Ghana.
| | - F Hasford
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana; Radiological and Medical Sciences Research Institute, Ghana Atomic Energy Commission Accra, Ghana
| | - S Inkoom
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana; Radiation Protection Institute, Ghana Atomic Energy Commission, Accra, Ghana
| | - M A Tetteh
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana; Radiology Department, Akershus University Hospital, Oslo, Norway
| | - P K Gyekye
- Department of Medical Physics, School of Nuclear and Allied Sciences, University of Ghana, Accra, Ghana; Radiological and Non-Ionizing Directorate, Nuclear Regulatory Authority, Accra, Ghana
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Pace M, Bonanno E, Borzì GR, Cavalli N, D'Anna A, Gueli AM, Stella G, Zirone L, Marino C. Organ dose in CT: Comparison between measurements and computational methods. Phys Med 2023; 112:102627. [PMID: 37348452 DOI: 10.1016/j.ejmp.2023.102627] [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: 04/29/2022] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023] Open
Abstract
PURPOSE This study aims to compare two methods for the organ dose evaluation in computed tomography (CT) in the head- and thorax regions: an experimental method, using radiochromic films, and a computational one, using a commercial software. METHODS Gafchromic® XR-QA2 and EBT-3 were characterized in terms of energetic, angular, and irradiation configurations dependence. Two free-in-air irradiation calibration configurations were employed using a CT scanner: with the sensitive surface of the film orthogonal (OC) and parallel (PC) to the beam axis. Different dose-response curves were obtained by varying the irradiation configurations and the beam quality (BQ). Subsequently, films were irradiated within an anthropomorphic phantom using CT-thorax and -head protocols, and the organ dose values obtained were compared with those provided by the commercial software. RESULTS At different configurations, an unchanged dose response was achieved with EBT-3, while a dose response of 15% was obtained with XR-QA2. By varying BQ, XR-QA2 showed a different response below 10%, while EBT-3 showed a variation below 5% for dose values >20 mGy. For films irradiation angle equal to 90°, the normalized to 0° relative response was 41% for the XR-QA2 model and 83% for the EBT-3 one. Organ dose values obtained with EBT-3 for both configurations and with XR-QA2 for OC were in agreement with the DW values, showing percentage discrepancies of less than 25%. CONCLUSIONS The obtained results showed the potential of EBT-3 in CT patient dosimetry since the lower angular dependence, compared to XR-QA2, compensates for low sensitivity in the diagnostic dose range.
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Affiliation(s)
- Martina Pace
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Elisa Bonanno
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Giuseppina Rita Borzì
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Nina Cavalli
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
| | - Alessia D'Anna
- Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy
| | - Anna Maria Gueli
- Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy
| | - Giuseppe Stella
- Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy.
| | - Lucia Zirone
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy; Department of Physics and Astronomy E. Majorana, University of Catania, Catania, Italy
| | - Camelo Marino
- Medical Physics Department, Humanitas Istituto Clinico Catanese, Misterbianco, CT, Italy
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Casiraghi M, Piliero MA, Bellesi L, Dufour M, Chatterjea A, Scarone P, Presilla S. Image quality and radiation dose in spinal surgery: a comparison of three imaging systems in phantom. J Med Imaging (Bellingham) 2023; 10:035001. [PMID: 37304527 PMCID: PMC10251430 DOI: 10.1117/1.jmi.10.3.035001] [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: 07/12/2022] [Revised: 05/02/2023] [Accepted: 05/19/2023] [Indexed: 06/13/2023] Open
Abstract
Purpose Using optimal settings for x-ray scans is crucial for obtaining three-dimensional images of high quality while keeping the patient dose low. Our work compares dose and image quality (IQ) of three intraoperative imaging systems [O-arm cone-beam computed tomography (CBCT), ClarifEye C-arm CBCT, and Airo computed tomography] used for spinal surgery. Approach Patients of 70, 90, and 110 kg were simulated with an anthropomorphic phantom by adding tissue-equivalent material. Titanium inserts were placed in the phantom spine for reproducing metal artifacts in the images. Organ dose was measured with thermo-luminescent dosimeters for effective dose (E ) calculation. Subjective IQ was assessed by ranking the images acquired with the manufacturer-defined imaging protocols. Objective IQ was assessed with a customized Catphan phantom. Results The ClarifEye protocols resulted in the lowest E ranging from 1.4 to 5.1 mSv according to phantom size and protocol. The highest E was measured for the high-definition protocol of O-arm (E 2.2 to 9 mSv) providing the best subjective IQ for imaging of the spine without titanium inserts. For the images with metal, the best IQ was obtained with ClarifEye. Airo (E 5.5 to 8.4 mSv) was ranked with the lowest IQ for images without metal while the rank improved for images with metal. Airo images had better uniformity, noise, and contrast sensitivity compared with CBCTs but worse high-contrast resolution. The values of these parameters were comparable between the CBCT systems. Conclusions Both CBCT systems provided better IQ compared with Airo for navigation of lumbar spinal surgery for the original phantom. Metal artifacts particularly affect O-arm images decreasing the subjective IQ. The high spatial resolution of CBCT systems resulted in a relevant parameter for the visibility of anatomical features important for spine navigation. Low dose protocols were enough to obtain a clinically acceptable contrast-to-noise ratio in the bones.
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Affiliation(s)
- Margherita Casiraghi
- Imaging Institute of Southern Switzerland, Medical Physics Division, Bellinzona, Switzerland
| | | | - Luca Bellesi
- Imaging Institute of Southern Switzerland, Medical Physics Division, Bellinzona, Switzerland
| | - Mathieu Dufour
- Imaging Institute of Southern Switzerland, Medical Physics Division, Bellinzona, Switzerland
| | | | - Pietro Scarone
- Neurocenter of Southern Switzerland, Neurosurgical Service, Lugano, Switzerland
| | - Stefano Presilla
- Imaging Institute of Southern Switzerland, Medical Physics Division, Bellinzona, Switzerland
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Costa PR, Tomal A, de Oliveira Castro JC, Nunes IPF, Nersissian DY, Sawamura MVY, Leão Filho H, Lee C. Diagnostic reference level quantities for adult chest and abdomen-pelvis CT examinations: correlation with organ doses. Insights Imaging 2023; 14:60. [PMID: 37024637 PMCID: PMC10079797 DOI: 10.1186/s13244-023-01403-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/11/2023] [Indexed: 04/08/2023] Open
Abstract
OBJECTIVES To evaluate correlations between DRL quantities (DRLq) stratified into patient size groups for non-contrast chest and abdomen-pelvis CT examinations in adult patients and the corresponding organ doses. METHODS This study presents correlations between DRLq (CTDIvol, DLP and SSDE) stratified into patient size ranges and corresponding organ doses shared in four groups: inside, peripheral, distributed and outside. The demographic, technical and dosimetric parameters were used to identify the influence of these quantities in organ doses. A robust statistical method was implemented in order to establish these correlations and its statistical significance. RESULTS Median values of the grouped organ doses are presented according to the effective diameter ranges. Organ doses in the regions inside the imaged area are higher than the organ doses in peripheral, distributed and outside regions, excepted to the peripheral doses associated with chest examinations. Different levels of statistical significance between organ doses and the DRLq were presented. CONCLUSIONS Correlations between DRLq and target-organ doses associated with clinical practice can support guidance's to the establishment of optimization criteria. SSDE demonstrated to be significant in the evaluation of organ doses is also highlighted. The proposed model allows the design of optimization actions with specific risk-reduction results.
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Affiliation(s)
- Paulo Roberto Costa
- Institute of Physics, University of São Paulo, R. Do Matão, 1371, Butantã, São Paulo, SP, 05508-090, Brazil.
| | - Alessandra Tomal
- Institute of Physics Gleb Watagin, University of Campinas, Campinas, Brazil
| | | | | | - Denise Yanikian Nersissian
- Institute of Physics, University of São Paulo, R. Do Matão, 1371, Butantã, São Paulo, SP, 05508-090, Brazil
| | | | - Hilton Leão Filho
- Division of Radiology, Medical School, University of São Paulo, São Paulo, Brazil
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health (NIH), Bethesda, MD, USA
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Gillespie CD, Yates A, Murphy MC, Hughes M, Ewins K, NíAinle F, Bolster F, Rowan M, Foley S, MacMahon PJ. Breast Shielding Combined With an Optimized Computed Tomography Pulmonary Angiography Pregnancy Protocol: A Special Use-Case for Shielding? J Thorac Imaging 2023; 38:36-43. [PMID: 36162076 DOI: 10.1097/rti.0000000000000677] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To determine the impact of breast shields on breast dose and image quality when combined with a low-dose computed tomography pulmonary angiography (CTPA) protocol for pregnancy. METHODS A low-dose CTPA protocol, with and without breast shields, was evaluated by anthropomorphic phantom and 20 prospectively recruited pregnant participants from January to October 2019. Thermoluminescent dosimeters measured surface and absorbed breast dose in the phantom and surface breast dose in participants. The Monte-Carlo method estimated the absorbed breast dose in participants. Image quality was assessed quantitatively by regions of interest analysis and subjectively by the Likert scale. Doses and image quality for CTPA alone were compared with CTPA with breast shields. RESULTS Mean surface and absorbed breast dose for CTPA alone were 1.3±0.4 and 2.8±1.5 mGy in participants, and 1.5±0.7 and 1.6±0.6 mGy in the phantom. Shielding reduced surface breast dose to 0.5±0.3 and 0.7±0.2 mGy in the phantom (66%) and study participants (48%), respectively. Absorbed breast dose reduced to 0.9±0.5 mGy (46%) in the phantom.Noise increased with breast shields at lower kV settings (80 to 100 kV) in the phantom; however, in study participants there was no significant difference between shield and no-shield groups for main pulmonary artery noise (no-shield: 34±9.8, shield: 36.3±7.2, P =0.56), SNR (no-shield: 11.2±3.7, shield: 10.8±2.6, P =0.74) or contrast-to-noise ratio (no-shield: 10.0±3.3, shield: 9.3±2.4, P =0.6). Median subjective image quality scores were comparable (no-shield: 4.0, interquartile range: 3.5 to 4.4, shield: 4.3, interquartile range: 4.0 to 4.5). CONCLUSION Combining low-dose CTPA with breast shields confers additional breast-dose savings without impacting image quality and yields breast doses approaching those of low-dose scintigraphy, suggesting breast shields play a role in protocol optimization for select groups.
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Affiliation(s)
| | | | | | | | - Karl Ewins
- Haematology, Mater Misericordiae University Hospital
| | | | - Ferdia Bolster
- Departments of Radiology
- School of Medicine, University College Dublin
| | - Michael Rowan
- Department of Medical Physics, St James Hospital, Dublin, Ireland
| | - Shane Foley
- Radiography & Diagnostic Imaging, School of Medicine, University College Dublin
| | - Peter J MacMahon
- Departments of Radiology
- School of Medicine, University College Dublin
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Radiation dose assessment in multiple injured patients using whole-body computed tomography. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2022. [DOI: 10.1016/j.jrras.2022.100465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Lu H, Meng T, You Y, Liu Y, He K, Kan Y, Zhang H. PHANTOM EXPERIMENTAL STUDY ON PATIENT DOSES OBTAINED FROM 320-MULTIDETECTOR-ROW COMPUTED TOMOGRAPHY IN WHOLE-BRAIN PERFUSION SCAN. RADIATION PROTECTION DOSIMETRY 2022; 198:1424-1434. [PMID: 36125221 DOI: 10.1093/rpd/ncac178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/28/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
This study aimed to precisely evaluate organ dose and effective dose (E) obtained from a 320-multidetector-row computed tomography (CT) scanner in brain perfusion scans and to estimate the conversion factor (k) between E and dose length product (DLP). A total of 270 thermoluminescent dosemeters were implanted in a male anthropomorphic phantom to measure air kerma. The ratios of mass-energy absorption coefficients were used to convert air kerma into organ doses. The organ doses ranged from 0.01 to 150 mGy. Doses in brain, salivary glands and red bone marrow were relatively high, and dose in eye lens reached about 110 mGy. The resulting effective dose was 5.30 mSv. The resulting conversion factor k = (0.0022 ± 0.0002) mSv·(mGy·cm)-1 was not significantly different from that of 0.0021 mSv·(mGy·cm)-1 reported for head CT scan in ICRP Publication 102.
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Affiliation(s)
- Heqing Lu
- Department of Medical Equipment, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Ting Meng
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Yang You
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Ying Liu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Kai He
- Department of Logistics Support, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Yandong Kan
- Department of Logistics Support, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Haowei Zhang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
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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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12
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D'Souza AN, Sayyed M, Karunakara N, Al-Ghamdi H, Almuqrin AH, Elsafi M, Khandaker MU, Kamath SD. TeO2–SiO2–B2O3 glasses doped with CeO2 for gamma radiation shielding and dosimetry application. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110233] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Optimization of Image Quality and Organ Absorbed Dose for Pediatric Chest X-Ray Examination: In-House Developed Chest Phantom Study. Radiol Res Pract 2022; 2022:3482458. [PMID: 35469151 PMCID: PMC9034961 DOI: 10.1155/2022/3482458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/26/2022] [Accepted: 03/28/2022] [Indexed: 11/17/2022] Open
Abstract
Purpose This study aimed to identify proper exposure techniques to maintain optimal diagnostic image quality with minimum radiation dose for anteroposterior chest X-ray projection in pediatric patients. Methods Briefly, an in-house developed pediatric chest phantom was constructed. Next, nanodot OSLDs were used for organ absorbed dose measurement and placed in the lung area, and the phantom was exposed to various exposure techniques (ranging from 50 to 70 kVp with 1.6, 2, and 2.5 mAs). After that, the phantom was used to assess image quality parameters, including SNR and CNR. Two radiologists assessed the subjective image quality using a visual grading analysis (VGA) technique. Finally, the figure of merit (FOM) was analyzed. Results The developed phantom was constructed successfully and could be useful for dose measurement and image quality assessment. The absorbed dose varied from 0.009 to 0.031 mGy for the range of exposure techniques used. SNR and CNR showed a gradually increasing trend, while kVp and mAs values were increased. The highest kVp (70 kVp) produced the highest SNR and CNR, exhibiting a significant difference compared with 50 and 60 kVp (P < 0.05). The overall VGA score was 3.2 ± 0.3, and the low kVp technique demonstrated better image quality compared with the reference image. Conclusion The optimized exposure technique was identified as 60 kV and 2.5 mAs, indicating the highest FOM score. This work revealed practicable techniques that could be implemented into clinical practice for performing pediatric chest radiography.
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14
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Reduced Chest Computed Tomography Scan Length for Patients Positive for Coronavirus Disease 2019: Dose Reduction and Impact on Diagnostic Utility. J Comput Assist Tomogr 2022; 46:576-583. [PMID: 35405727 PMCID: PMC9296570 DOI: 10.1097/rct.0000000000001312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
METHODS This study used the Personalized Rapid Estimation of Dose in CT (PREDICT) tool to estimate patient-specific organ doses from CT image data. The PREDICT is a research tool that combines a linear Boltzmann transport equation solver for radiation dose map generation with deep learning algorithms for organ contouring. Computed tomography images from 74 subjects in the Medical Imaging Data Resource Center-RSNA International COVID-19 Open Radiology Database data set (chest CT of adult patients positive for COVID-19), which included expert annotations including "infectious opacities," were analyzed. First, the full z-scan length of the CT image data set was evaluated. Next, the z-scan length was reduced from the left hemidiaphragm to the top of the aortic arch. Generic dose reduction based on dose length product (DLP) and patient-specific organ dose reductions were calculated. The percentage of infectious opacities excluded from the reduced z-scan length was used to quantify the effect on diagnostic utility. RESULTS Generic dose reduction, based on DLP, was 69%. The organ dose reduction ranged from approximately equal to 18% (breasts) to approximately equal to 64% (bone surface and bone marrow). On average, 12.4% of the infectious opacities were not included in the reduced z-coverage, per patient, of which 5.1% were above the top of the arch and 7.5% below the left hemidiaphragm. CONCLUSIONS Limiting z-scan length of chest CTs reduced radiation dose without significantly compromising diagnostic utility in COVID-19 patients. The PREDICT demonstrated that patient-specific organ dose reductions varied from generic dose reduction based on DLP.
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15
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Lee C, Won T, Yeom YS, Griffin K, Lee C, Kim KP. Organ dose conversion coefficients in CT scans for Korean adult males and females. NUCLEAR ENGINEERING AND TECHNOLOGY 2022; 54:681-688. [PMID: 38895599 PMCID: PMC11185357 DOI: 10.1016/j.net.2021.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Dose monitoring in CT patients requires accurate dose estimation but most of the CT dose calculation tools are based on Caucasian computational phantoms. We established a library of organ dose conversion coefficients for Korean adults by using four Korean adult male and two female voxel phantoms combined with Monte Carlo simulation techniques. We calculated organ dose conversion coefficients for head, chest, abdomen and pelvis, and chest-abdomen-pelvis scans, and compared the results with the existing data calculated from Caucasian phantoms. We derived representative organ doses for Korean adults using Korean CT dose surveys combined with the dose conversion coefficients. The organ dose conversion coefficients from the Korean adult phantoms were slightly greater than those of the ICRP reference phantoms: up to 13% for the brain doses in head scans and up to 10% for the dose to the small intestine wall in abdominal scans. We derived Korean representative doses to major organs in head, chest, and AP scans using mean CTDIvol values extracted from the Korean nationwide surveys conducted in 2008 and 2017. The Korean-specific organ dose conversion coefficients should be useful to readily estimate organ absorbed doses for Korean adult male and female patients undergoing CT scans.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | | | - Yeon Soo Yeom
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Keith Griffin
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Choonik Lee
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Kwang Pyo Kim
- Department of Nuclear Engineering, Kyung Hee University, Gyeonggi-do, South Korea
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16
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Karim M, Harun H, Kayun Z, Aljewaw O, Azizan S, Rafiz N, Muhammad N. Paediatric radiation dose and cancer risk associated with body effective diameter during CT thorax examination. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Ma R, Qiu R, Wu Z, Ren L, Hu A, Li WB, Li J. Development of Chinese mesh-type pediatric reference phantom series and application in dose assessment of Chinese undergoing computed tomography scanning. Phys Med Biol 2021; 66. [PMID: 34407526 DOI: 10.1088/1361-6560/ac1ef1] [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: 01/17/2020] [Accepted: 08/18/2021] [Indexed: 11/12/2022]
Abstract
Pediatric patients are in a growing stage with more dividing cells than adults. Therefore, they are more sensitive to the radiation dose when undergoing computed tomography (CT) scanning. It is necessary and essential to assess the organ absorbed dose and effective dose to children. Monte Carlo simulation with computational phantoms is one of the most used methods for dose calculation in medical imaging and radiotherapy. Because of the vast change of the pediatric body with age increasing, many research groups developed series pediatric phantoms for various ages. However, most of the existing pediatric reference phantoms were developed based on Caucasian populations, which is not conformable to Chinese pediatric patients. The use of different phantoms can contribute to a difference in the dose calculation. To assess the CT dose of Chinese pediatric patients more accurately, we developed the Chinese pediatric reference phantoms series, including the 3-month (CRC3m), 1-year-old (CRC01), 5-year-old (CRC05), 10-year-old (CRC10), 15-year-old male (CRCM15), and a 15-year-old female (CRCF15) phantoms. Furthermore, we applied them to dose assessment of patients undergoing CT scanning. The GE LightSpeed 16 CT scanner was simulated and the paper presents the detailed process of phantoms development and the establishment of the CT dose database (with x-ray tube voltages of 120, 100 and 80 kVp, with collimators of 20, 10, and 5 mm width, with filters for head and body), compares for the 1-year-old results with other results based on different phantoms and analyzes the CT dose calculation results. It was found that the difference in phantoms' characteristics, organ masses and positions had a significant impact on the CT dose calculation outcomes. For the 1-year-old phantom, the dose results of organs fully covered by the x-ray beam were within 10% difference from the results of other studies. For organs partially covered and not covered by the scan range, the maximum differences came up to 84% (stomach dose, chest examinations) and 463% (gonads dose, chest examinations) respectively. The findings are helpful for the dose optimization of Chinese pediatric patients undergoing CT scanning. The developed phantoms could be applied in dose estimation of other medical modalities.
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Affiliation(s)
- Ruiyao Ma
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Institute of Radiation Medicine, Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Neuherberg, Germany.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing, People's Republic of China
| | - Rui Qiu
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing, People's Republic of China
| | - Zhen Wu
- Joint Institute of Tsinghua University & Nuctech Company Limited Beijing, People's Republic of China
| | - Li Ren
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing, People's Republic of China
| | - Ankang Hu
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing, People's Republic of China
| | - Wei Bo Li
- Institute of Radiation Medicine, Helmholtz Zentrum München-German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Junli Li
- Department of Engineering Physics, Tsinghua University, Beijing, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Tsinghua University, Ministry of Education, Beijing, People's Republic of China
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18
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Xue SW, Luo YK, Jiao ZY, Xu L. Clinical value of SMI Combined with Low-Dose CT Scanning in differential diagnosis of Thyroid Lesions and Tumor Staging. Pak J Med Sci 2021; 37:1347-1352. [PMID: 34475910 PMCID: PMC8377899 DOI: 10.12669/pjms.37.5.4144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 04/05/2021] [Accepted: 04/25/2021] [Indexed: 11/15/2022] Open
Abstract
Objectives To investigate the clinical value of Superb Microvascular Imaging (SMI) combined with low dose CT scanning in differential diagnosis of thyroid lesions and tumor staging. Methods A total of 120 patients with thyroid nodules admitted to the Chinese PLA General Hospital from January 2017 to July 2020 were selected. Paired design was adopted in this study. SMI and SMI combined with low-dose CT scanning were respectively carried out to these patients. The results were judged by two senior imaging physicians and two senior sonographers respectively. And t-test, χ2 test, Pearson correlation coefficient check and other methods were adopted to comparatively analyze the above two methods and the pathological results after operation or puncture. Results Compared with pathologic findings, the coincidence rate of SMI was 40%, and the coincidence rate of SMI combined with low dose CT scanning was 84%. The difference was significant (p=0.00); among the 120 thyroid nodule patients, 50 were diagnosed as malignant by pathological diagnosis, and 70 as benign; 27 malignant cases and 93 benign cases were detected by SMI; 48 malignant cases and 72 benign cases were detected by SMI combined with low dose CT scanning. The sensitivity and accuracy of the latter were significantly higher than those of the former, and the difference was statistically significant (p=0.00); the enhancement, edge sharpness and homogeneity of SMI increased with the increase of tumor malignancy, showing positive correlation property. Conclusion SMI combined with low dose CT scanning has a higher diagnostic coincidence rate. Its sensitivity and accuracy are significantly superior. With the increase of tumor malignancy, the enhancement and unhomogeneity of SMI increase, and the edge is more blurred. That suggests: with the increase of tumor malignancy, neovascularization in the tumor is more obvious and more unevenly distributed; the increase of edge blur indicates more obvious tumor infiltration. The method has considerable clinical value for predicting the malignancy of tumors.
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Affiliation(s)
- Shao-Wei Xue
- Shao-wei Xue, Department of Ultrasound Diagnosis, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, P. R. China
| | - Yu-Kun Luo
- Yu-kun Luo, Department of Ultrasound Diagnosis, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, P. R. China
| | - Zi-Yu Jiao
- Zi-yu Jiao, Department of Ultrasound Diagnosis, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, P. R. China
| | - Lin Xu
- Lin Xu, Department of Radiology, The First Medical Center of Chinese PLA General Hospital, Beijing 100853, P. R. China
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19
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Won T, Lee AK, Choi HD, Lee C. Radiation dose from computed tomography scans for Korean pediatric and adult patients. JOURNAL OF RADIATION PROTECTION AND RESEARCH 2021; 46:98-105. [PMID: 38894707 PMCID: PMC11185358 DOI: 10.14407/jrpr.2021.00010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/03/2021] [Indexed: 06/21/2024]
Abstract
Background In recent events of the Coronavirus Disease 2019 (COVID-19) pandemic, CT scans are being globally used as a complement to the reverse-transcription polymerase chain reaction (RT-PCR) tests. It will be important to be aware of major organ dose levels, which are more relevant quantity to derive potential long-term adverse effect, for Korean pediatric and adult patients undergoing CT for COVID-19. Materials and Methods We calculated organ dose conversion coefficients for Korean pediatric and adult CT patients directly from Korean pediatric and adult computational phantoms combined with Monte Carlo radiation transport techniques. We then estimated major organ doses delivered to the Korean child and adult patients undergoing CT for COVID-19 combining the dose conversion coefficients and the international survey data. We also compared our Korean dose conversion coefficients with those from Caucasian reference pediatric and adult phantoms. Results and discussion Based on the dose conversion coefficients we established in this study and the international survey data of COVID-19-related CT scans, we found that Korean 7-year-old child and adult males may receive about 4 - 32 mGy and 3 - 21 mGy of lung dose, respectively. We learned that the lung dose conversion coefficient for the Korean child phantom was up to 1.5-fold greater than that for the Korean adult phantom. We also found no substantial difference in dose conversion coefficients between Korean and Caucasian phantoms. Conclusion We estimated radiation dose delivered to the Korean child and adult phantoms undergoing COVID-19-related CT examinations. The dose conversion coefficients derived for different CT scan types can be also used universally for other dosimetry studies concerning Korean CT scans. We also confirmed that the Caucasian-based CT organ dose calculation tools may be used for the Korean population with reasonable accuracy.
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Affiliation(s)
- Tristan Won
- Winston Churchill High School, Potomac, MD 20854
| | - Ae-Kyoung Lee
- Electronics and Telecommunications Research Institute, Daejeon, South Korea
| | - Hyung-do Choi
- Electronics and Telecommunications Research Institute, Daejeon, South Korea
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850
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20
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Yoon J, Lee C. Conversion factors to derive organ doses for canine subjects undergoing CT examinations. Vet Radiol Ultrasound 2021; 62:421-428. [PMID: 33987905 PMCID: PMC10789152 DOI: 10.1111/vru.12979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 03/09/2021] [Accepted: 03/09/2021] [Indexed: 11/27/2022] Open
Abstract
Although a large number of CT scans are being conducted on small animals, especially in Western countries, little is known of absorbed dose from veterinary CT scans. In the current retrospective analytical study, we estimated the radiation dose delivered to dogs from CT scans with various scan protocols and compared the results with those of human patients. We adopted a total of three computerized canine models with three sizes combined with a computer simulation model of a CT scanner. The eyes of the dog model received the greatest dose, 1.10 mGy/mGy, in the head scan, followed by a brain dose of 0.85 mGy/mGy. In the chest, abdomen-pelvis (AP), chest-abdomen-pelvis, and head-chest-abdomen-pelvis scans, the heart wall (0.93 mGy/mGy), ovaries (0.99 mGy/mGy), lungs (1.12 mGy/mGy), and thyroid (1.23 mGy/mGy) received the greatest organ doses, respectively. The smallest dog model received up to 1.4-fold greater organ doses than the largest dog in both the chest and AP scans. Overall, the medium-size canine model received organ doses comparable to those of the 1-year-old child model in the head scan, the 5-year-old child in chest scan, and the 10-year-old child in AP scan. The organ dose conversion factors derived from this study should help evaluate absorbed dose for canine patients undergoing CT exams.
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Affiliation(s)
- James Yoon
- Paul VI Catholic High School, Fairfax, Virginia, USA
| | - Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland, USA
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21
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Delis H, Homolka P, Chapple C, Costa P, Attalla E, Lubis L, Sackey T, Fahey F, Lassmann M, Poli G. Developing and implementing a multi-modality imaging optimization study in paediatric radiology: Experience and recommendations from an IAEA coordinated research project. Phys Med 2021; 82:255-265. [DOI: 10.1016/j.ejmp.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 02/04/2021] [Accepted: 02/15/2021] [Indexed: 11/15/2022] Open
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22
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Casiraghi M, Scarone P, Bellesi L, Piliero MA, Pupillo F, Gaudino D, Fumagalli G, Del Grande F, Presilla S. Effective dose and image quality for intraoperative imaging with a cone-beam CT and a mobile multi-slice CT in spinal surgery: A phantom study. Phys Med 2020; 81:9-19. [PMID: 33310424 DOI: 10.1016/j.ejmp.2020.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 09/30/2020] [Accepted: 11/02/2020] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To compare the effective dose (ED) and image quality (IQ) of O-arm cone-beam CT (Medtronic, Minneapolis, MN, USA) and Airo multi-slice CT (Brainlab AG, Munich, Germany) for intraoperative-CT (i-CT) in spinal surgery. METHODS The manufacturer-defined protocols available in the O-arm and Airo systems for three-dimensional lumbar spine imaging were compared. Organ dose was measured both with thermo-luminescent dosimeters and GafChromic films in the Alderson RadiationTherapy anthropomorphic phantom. A subjective analysis was performed by neurosurgeons to compare the clinical IQ of the anthropomorphic phantom images acquired with the different i-CT systems and imaging protocols. Image uniformity, noise, contrast-to-noise-ratio (CNR), and spatial resolution were additionally assessed with the Catphan 504 phantom. RESULTS O-arm i-CT caused 56% larger ED than Airo due to the high definition (HD) imaging protocol. The noise was larger for O-arm images leading to a lower CNR than that measured for Airo. Moreover, scattering and beam hardening effects were observed in the O-arm images. Better spatial resolution was measured for the O-arm system (9 lp/cm) than for Airo (4 lp/cm). For all the investigated protocols, O-arm was found to be better for identifying anatomical features important for accurate pedicle screw positioning. CONCLUSIONS According to phantom measurements, the HD protocol of O-arm offered better clinical IQ than Airo but larger ED. The larger noise of O-arm images did not compromise the clinical IQ while the superior spatial resolution of this system allowed a better visibility of anatomical features important for pedicle screw positioning in the lumbar region.
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Affiliation(s)
- Margherita Casiraghi
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
| | - Pietro Scarone
- Service of Neurosurgery, Neurocenter of Southern Switzerland, 6900 Lugano, Switzerland.
| | - Luca Bellesi
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
| | - Maria Antonietta Piliero
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
| | - Francesco Pupillo
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
| | - Diego Gaudino
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
| | - Giulia Fumagalli
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
| | - Filippo Del Grande
- Department of Radiology, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Lugano, 6900 Lugano, Switzerland.
| | - Stefano Presilla
- Medical Physics Division, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, Ospedale Regionale di Bellinzona e Valli, 6500 Bellinzona, Switzerland.
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23
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Perisinakis K, Ntoufas N, Velivassaki M, Tzedakis A, Myronakis M, Hatzidakis A, Damilakis J. Effect of scan projection radiography coverage on tube current modulation in pediatric and adult chest CT. Z Med Phys 2020; 30:259-270. [PMID: 32513526 DOI: 10.1016/j.zemedi.2020.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/22/2020] [Accepted: 05/03/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate the effect of scan projection radiography (SPR) coverage on tube current modulation in pediatric and adult thoracic CT examinations. METHODS Sixty pediatric and 60 adult chest CT examinations were retrospectively studied to determine the incidence rate of examinations involving SPRs that did not include the entire image volume (IV) or the entire primarily exposed body volume (PEBV). The routine chest CT acquisition procedure on a modern 64-slice CT system was imitated on five anthropomorphic phantoms of different size. SPRs of varying length were successively acquired. The same IV was prescribed each time and the computed tube current modulation plan was recorded. The SPR boundaries were altered symmetrically by several steps of ±10mm with respect to the IV boundaries. RESULTS The upper IV boundary was found to be excluded from SPR in 52% of pediatric and 40% adult chest CT examinations. The corresponding values for the lower boundary were 15% and 20%, respectively. The computed tube current modulation was found to be considerably affected when the SPR did not encompass the entire IV. SPR deficit of 3cm was found to induce up to 46% increase in the computed tube current value to be applied during the first tube rotations over lung apex. CONCLUSIONS The tube current modulation mechanism functions properly only if the IV set by the operator is entirely included in the localizing SPR image. Operators should cautiously set the SPR boundaries to avoid partial exclusion of prescribed IV from SPRs and thus achieve optimum tube current modulation.
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Affiliation(s)
- Kostas Perisinakis
- University of Crete, Medical School, Department of Medical Physics, 71003 Heraklion, Crete, Greece; University Hospital of Heraklion, Department of Medical Physics, P.O. Box 1352, 71110 Heraklion, Crete, Greece.
| | - Nikos Ntoufas
- University of Crete, Medical School, Department of Medical Physics, 71003 Heraklion, Crete, Greece
| | - Mary Velivassaki
- University Hospital of Heraklion, Department of Medical Physics, P.O. Box 1352, 71110 Heraklion, Crete, Greece
| | - Antonis Tzedakis
- University Hospital of Heraklion, Department of Medical Physics, P.O. Box 1352, 71110 Heraklion, Crete, Greece
| | - Marios Myronakis
- University of Crete, Medical School, Department of Medical Physics, 71003 Heraklion, Crete, Greece; Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School
| | - Adam Hatzidakis
- University of Crete, Medical School, Department of Radiology, Heraklion, Crete, Greece
| | - John Damilakis
- University of Crete, Medical School, Department of Medical Physics, 71003 Heraklion, Crete, Greece; University Hospital of Heraklion, Department of Medical Physics, P.O. Box 1352, 71110 Heraklion, Crete, Greece
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Modak P, Modak B. Exploring the role of vacancy defects in the optical properties of LiMgPO 4. Phys Chem Chem Phys 2020; 22:16244-16257. [PMID: 32643738 DOI: 10.1039/d0cp02425b] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Linearity in dose response up to very high radiation doses and sufficient sensitivity to even low radiation doses are extremely important for the measurement of radiation dose in the field of radiation technology, ranging from medical to industrial applications. Olivine type LiMgPO4 has been shown immense interest as a phosphor material in the fields of thermoluminescence and optically stimulated luminescence dosimetry. In the present study, we have explored the role of different vacancy defects in the optical properties of LiMgPO4 aiming at enhancing its sensitivity for the measurement of radiation dose. For this purpose, we have systematically investigated the electronic structure of LiMgPO4 in the absence and presence of various vacancy defects using density functional theory as a tool. The present study considers all possible vacancy defects including neutral, charged and mixed lattice vacancy defects in LiMgPO4. To find the most energetically favourable vacancy defect, we have compared the defect formation energy of all the vacancy defects. We have also calculated vacancy formation energy in different chemical environments to investigate how the formation of different types of vacancy defect can be controlled by tuning the chemical environment. Finally, the origin of the different optical properties of LiMgPO4 has been explained by using a possible mechanism based on our detailed electronic structure calculations. Thus, the present study is believed to provide valuable insight for the development of materials with improved features for the measurement of radiation dose.
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Affiliation(s)
- Pampa Modak
- RSD, Atomic Energy Regulatory Board, Mumbai 400 094, India and Homi Bhabha National Institute, Mumbai 400 094, India
| | - Brindaban Modak
- Homi Bhabha National Institute, Mumbai 400 094, India and Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India.
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25
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Lee C, Liu J, Griffin K, Folio L, Summers RM. Adult patient-specific CT organ dose estimations using automated segmentations and Monte Carlo simulations. Biomed Phys Eng Express 2020; 6:045016. [PMID: 33444276 DOI: 10.1088/2057-1976/ab98e6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We aimed to determine feasibility in calculating patient-specific organ doses for abdominal computed tomography (CT) exams using an automated segmentation technique dedicated to abdominal organs combined with Monte Carlo simulation of a clinical CT scanner. We conducted the automated segmentation of five major abdominal organs (left and right kidneys, pancreas, spleen, and liver) for ten adult patients and calculated organ-specific doses for each patient. We observed significant variability (Coefficient of Variation up to 32%) in organ mass across the ten patients, which was up to two-fold greater or smaller than the reference organ mass for the ICRP reference adult male and female. Comparison of patient-specific organ dose per CTDIvol with those from the ICRP reference phantoms confirmed that reference phantom-based dose reporting programs cannot capture inter-patient dose variability, and dosimetric errors can go up to nearly 40%. We demonstrated an automated method for patient-specific organ dose calculations, which took about 45 min per patient. When the automatic segmentation method is extended to more organs and faster Monte Carlo calculation technique is employed, our method should be useful for patient-specific dose monitoring at the organ level and for epidemiological investigations of health risks in CT patients.
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Affiliation(s)
- Choonsik Lee
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States of America
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Realization of dysprosium doped lithium magnesium borate glass based TLD subjected to 1–100 Gy photon beam irradiations. Radiat Phys Chem Oxf Engl 1993 2019. [DOI: 10.1016/j.radphyschem.2019.05.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Tang H, Lin L, Zhang C, Tang Q. High-Sensitivity and Wide-Linear-Range Thermoluminescence Dosimeter LiMgPO 4:Tm,Tb,B for Detecting High-Dose Radiation. Inorg Chem 2019; 58:9698-9705. [PMID: 31283195 DOI: 10.1021/acs.inorgchem.9b00597] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
High-sensitivity and wide-linear-range thermoluminescence dosimeter (TLD) is of importance for detecting high-dose radiation in industry, medicine, and agriculture as well as materials and food processing. In this work, we synthesize a series of LiMgPO4 doped with Tm3+, Tb3+, and B3+ via a high-temperature solid-state reaction technique. To observe the effect of dopants, we first investigate the structure by Rietveld refinement of high-quality X-ray diffraction (XRD) data and then study the thermoluminescence (TL) properties of samples radiated by β-rays in detail. The TL signal of LiMgPO4:Tm,Tb,B is originated from Tm3+ 4f-4f transitions. The kinetic parameters are obtained through fitting the TL glow curve based on the general-order kinetics model, revealing that the dominant TL peak at ∼323 °C is related to ∼1.49 eV trap. Through constructing the vacuum-referred binding energy (VRBE) scheme, we uncover that this deep trap mainly originates from the Tb3+ dopant acted as the captured center of free hole. After codoping 0.6% B3+, the sensitivity of sample as TLD increases ∼170%. According to the radiation dose-dependent TL intensities, the sensitivity of LiMgPO4:Tm,Tb,B is about 200% larger than that of the commercial LiF:Mg,Cu,P at 0.08 Gy, and more sensitive at higher dose. Moreover, the studied sample has wider linear range (up to 10 000 Gy) toward high-dose side, good reproducibility (RSD ∼ 4.6%), and weak fading (∼8% after 34 days), and therefore has potential application as TLD for monitoring high-dose radiation.
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Affiliation(s)
- Huaming Tang
- School of Physics , Sun Yat-sen University , Guangzhou 510275 , China
| | - Litian Lin
- Guangdong Province Key Laboratory of Rare Earth Development and Application, Guangdong Research Institute of Rare Metals , Guangdong Academy of Science , Guangzhou 510651 , China
| | - Chunxiang Zhang
- School of Physics , Sun Yat-sen University , Guangzhou 510275 , China
| | - Qiang Tang
- School of Physics , Sun Yat-sen University , Guangzhou 510275 , China
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