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Tárnoki ÁD, Tárnoki DL, Dąbrowska M, Knetki-Wróblewska M, Frille A, Stubbs H, Blyth KG, Juul AD. New developments in the imaging of lung cancer. Breathe (Sheff) 2024; 20:230176. [PMID: 38595936 PMCID: PMC11003524 DOI: 10.1183/20734735.0176-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 01/25/2024] [Indexed: 04/11/2024] Open
Abstract
Radiological and nuclear medicine methods play a fundamental role in the diagnosis and staging of patients with lung cancer. Imaging is essential in the detection, characterisation, staging and follow-up of lung cancer. Due to the increasing evidence, low-dose chest computed tomography (CT) screening for the early detection of lung cancer is being introduced to the clinical routine in several countries. Radiomics and radiogenomics are emerging fields reliant on artificial intelligence to improve diagnosis and personalised risk stratification. Ultrasound- and CT-guided interventions are minimally invasive methods for the diagnosis and treatment of pulmonary malignancies. In this review, we put more emphasis on the new developments in the imaging of lung cancer.
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Affiliation(s)
- Ádám Domonkos Tárnoki
- Medical Imaging Centre, Semmelweis University, Budapest, Hungary
- National Tumour Biology Laboratory, Oncologic Imaging and Invasive Diagnostic Centre, National Institute of Oncology, Budapest, Hungary
| | - Dávid László Tárnoki
- Medical Imaging Centre, Semmelweis University, Budapest, Hungary
- National Tumour Biology Laboratory, Oncologic Imaging and Invasive Diagnostic Centre, National Institute of Oncology, Budapest, Hungary
| | - Marta Dąbrowska
- Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw, Warsaw, Poland
| | | | - Armin Frille
- Department of Respiratory Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Harrison Stubbs
- Glasgow Pleural Disease Unit, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Kevin G. Blyth
- Glasgow Pleural Disease Unit, Queen Elizabeth University Hospital, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
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Bagherzadeh S, Jabbari N, Khalkhali HR. Radiation dose and cancer risks from radiation exposure during abdominopelvic computed tomography (CT) scans: comparison of diagnostic and radiotherapy treatment planning CT scans. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2021; 60:579-589. [PMID: 34542682 DOI: 10.1007/s00411-021-00942-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/04/2021] [Indexed: 06/13/2023]
Abstract
In the present study, radiation doses and cancer risks resulting from abdominopelvic radiotherapy planning computed tomography (RP-CT) and abdominopelvic diagnostic CT (DG-CT) examinations are compared. Two groups of patients who underwent abdominopelvic CT scans with RP-CT (n = 50) and DG-CT (n = 50) voluntarily participated in this study. The two groups of patients had approximately similar demographic features including mass, height, body mass index, sex, and age. Radiation dose parameters included CTDIvol, dose-length product, scan length, effective tube current, and pitch factor, all taken from the CT scanner console. The ImPACT software was used to calculate the patient-specific radiation doses. The risks of cancer incidence and mortality were estimated based on the BEIR VII report of the US National Research Council. In the RP-CT group, the mean ± standard deviation of cancer incidence risk for all cancers, leukemia, and all solid cancers was 621.58 ± 214.76, 101.59 ± 27.15, and 516.60 ± 189.01 cancers per 100,000 individuals, respectively, for male patients. For female patients, the corresponding risks were 742.71 ± 292.35, 74.26 ± 20.26, and 667.03 ± 275.67 cancers per 100,000 individuals, respectively. In contrast, for DG-CT cancer incidence risks were 470.22 ± 170.07, 78.23 ± 18.22, and 390.25 ± 152.82 cancers per 100,000 individuals for male patients, while they were 638.65 ± 232.93, 62.14 ± 13.74, and 575.73 ± 221.21 cancers per 100,000 individuals for female patients. Cancer incidence and mortality risks were greater for RP-CT than for DG-CT scans. It is concluded that the various protocols of abdominopelvic CT scans, especially the RP-CT scans, should be optimized with respect to the radiation doses associated with these scans.
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Affiliation(s)
- Saeed Bagherzadeh
- Department of Medical Physics, Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Nasrollah Jabbari
- Solid Tumor Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran.
| | - Hamid Reza Khalkhali
- Patient Safety Research Center, Department of Biostatistics and Epidemiology, Urmia University of Medical Sciences, Urmia, Iran
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Matsubara K. [4. Phantoms for Dose Evaluation in Computed Tomography]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2021; 77:406-409. [PMID: 33883376 DOI: 10.6009/jjrt.2021_jsrt_77.4.406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kosuke Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University
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Chumak VV, Petrenko NP, Bakhanova OV, Voloskyi VM, Treskunova TV. USE OF ANTHROPOMORPHIC HETEROGENEOUS PHYSICAL PHANTOMS FOR VALIDATION OF COMPUTATIONAL DOSIMETRY OF MEDICAL PERSONNEL AND PATIENTS. PROBLEMY RADIAT︠S︡IĬNOÏ MEDYT︠S︡YNY TA RADIOBIOLOHIÏ 2020; 25:148-176. [PMID: 33361833 DOI: 10.33145/2304-8336-2020-25-148-176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Indexed: 11/10/2022]
Abstract
In the dosimetry of ionizing radiation, the phantoms of the human body, which are used as a replacement for thehuman body in physical measurements and calculations, play an important, but sometimes underestimated, role.There are physical phantoms used directly for measurements, and mathematical phantoms for computationaldosimetry. Their complexity varies from simple geometry applied for calibration purposes up to very complex, whichsimulates in detail the shapes of organs and tissues of the human body. The use of physical anthropomorphic phantoms makes it possible to effectively optimize radiation doses by adjusting the parameters of CT-scanning (computed tomography) in accordance with the characteristics of the patient without compromising image quality. The useof phantoms is an indispensable approach to estimate the actual doses to the organs or to determine the effectivedose of workers - values that are regulated, but cannot be directly measured.The article contains an overview of types, designs and the fields of application of anthropomorphic heterogeneousphysical phantoms of a human with special emphasis on their use for validation of models and methods of computational dosimetry.
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Affiliation(s)
- V V Chumak
- State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», 53 Yuriia Illienka St., Kyiv, 04050, Ukraine
| | - N P Petrenko
- State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», 53 Yuriia Illienka St., Kyiv, 04050, Ukraine
| | - O V Bakhanova
- State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», 53 Yuriia Illienka St., Kyiv, 04050, Ukraine
| | - V M Voloskyi
- State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», 53 Yuriia Illienka St., Kyiv, 04050, Ukraine
| | - T V Treskunova
- State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», 53 Yuriia Illienka St., Kyiv, 04050, Ukraine
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Aziz MU, Hall MK, Pressacco J, Maki JH. Magnetic Resonance Angiography in Pulmonary Embolism: A Review. Curr Probl Diagn Radiol 2019; 48:586-591. [DOI: 10.1067/j.cpradiol.2018.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 08/03/2018] [Accepted: 08/06/2018] [Indexed: 11/22/2022]
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Maziar A, Paydar R, Azadbakht G, Shahbazi-Gahrouei D. Estimation of Absorbed Dose of the Thyroid Gland in Patients Undergoing 64-Slice Head Computed Tomography and Comparison the Results with ImPACT Software and Computed Tomography Scan Dose Index. JOURNAL OF MEDICAL SIGNALS & SENSORS 2019; 9:190-195. [PMID: 31544059 PMCID: PMC6743239 DOI: 10.4103/jmss.jmss_40_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Thyroid exposure to radiation in brain computed tomography (CT) scan is of great value since it is considered as a vital organ. This study aimed to investigate the absorbed dose of thyroid by various protocols of head CT in patients referring to 64-slice CT scan center and to compare the values with the calculated dose by imaging performance and assessment of CT (ImPACT) method. Also, the values of CT scan dose index (CTDI) were calculated with semiconductor detector. In this cross-sectional study, 120 outpatients including three groups of forty individuals over 40 years old referring to the hospital radiology centers in Tehran for head CT were chosen and 3 thermo-luminescence dosimeter (TLD-GR200) were applied on thyroid gland of each patient. For brain CT, Absorbed and effective doses of thyroid gland were calculated by ImPACT software. In addition, semiconductor detector in head CTDI phantom calculated CTDI for the applied protocols. Mean effective dose of thyroid gland in brain scan group was calculated by TLD and ImPACT software which showed no significant difference (P < 0.001). Mean effective dose of thyroid gland in unidirectional and bi-directional sinus scan by TLD and ImPACT software were different significantly (P < 0.001). Also, the differences between CTDI values shown by brain and sinus scan protocol with semiconductor detector and those CTDI were significant (P < 0.001). The calculated values of absorbed dose and effective doses of thyroid by TLD and ImPACT software were not significantly different. Mean effective dose calculated for thyroid gland in head scans by TLD and ImPACT was less than the annual permissive level for thyroid gland suggested by International Committee on Radiological Protection. In this study, calculated values of thyroid effective dose in brain scan with 64-slice scanner were less than the calculated values in a similar study.
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Affiliation(s)
- Asghar Maziar
- Department of Radiation Sciences, Radiation Biology Research Centre, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Reza Paydar
- Department of Radiation Sciences, Radiation Biology Research Centre, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ghazal Azadbakht
- Department of Radiation Sciences, Radiation Biology Research Centre, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Daryoush Shahbazi-Gahrouei
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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Pelegrino Bastos Maués NH, Fattori Alves AF, Menegatti Pavan AL, Marrone Ribeiro S, Yamashita S, Petean Trindade A, Mascarenhas YM, Nicolucci P, Rodrigues de Pina D. ABDOMEN-PELVIS COMPUTED TOMOGRAPHY PROTOCOL OPTIMIZATION: AN IMAGE QUALITY AND DOSE ASSESSMENT. RADIATION PROTECTION DOSIMETRY 2019; 184:66-72. [PMID: 30371858 DOI: 10.1093/rpd/ncy181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/20/2018] [Accepted: 10/19/2018] [Indexed: 06/08/2023]
Abstract
Computed tomography (CT) has a high level of sensitivity and specificity for the diagnosis and follow-up of pathologies of the abdomen-pelvis region. Some features, such as automatic tube current modulation (ATCM), permits the acquisition of quality images with low radiation doses. This study evaluated the image quality and radiation dose of abdomen-pelvis CT protocols with ATCM technique. Were performed five CT protocols using 16-slice and 64-slice scanners, an anthropomorphic phantom for dosimetric measurements, an analytical phantom and retrospective examinations for image quality analysis. Were found significant reduction in effective dose. The highest absorbed doses were found in the stomach and spleen (56.1 and 47.2 mGy, respectively). Objective parameters as noise, low contrast and spatial resolution did not significantly differ between the protocols (p > 0.05). All protocols received the range of 'Optimum/Acceptable' in patient's image quality analysis. This methodology can be reproduced in any clinical routine to optimize CT protocols.
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Affiliation(s)
| | - Allan Felipe Fattori Alves
- São Paulo State University (UNESP), Instituto de Biociências de Botucatu, Departamento de Física e Biofísica, Botucatu, São Paulo, Brazil
| | - Ana Luiza Menegatti Pavan
- São Paulo State University (UNESP), Instituto de Biociências de Botucatu, Departamento de Física e Biofísica, Botucatu, São Paulo, Brazil
| | - Sergio Marrone Ribeiro
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
| | - Seizo Yamashita
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
| | - André Petean Trindade
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
| | | | - Patrícia Nicolucci
- Universidade de São Paulo (USP), Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Centro de Instrumentação, Dosimetria e Radioproteção (CIDRA), Av. Bandeirantes, 3900 Bairro Monte Alegre, Ribeirão Preto, São Paulo, Brazil
| | - Diana Rodrigues de Pina
- São Paulo State University (UNESP), Faculdade de Medicina de Botucatu, Departamento de Doenças Tropicais e Diagnóstico por Imagem, Botucatu, São Paulo, Brazil
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Bouaoun A, Ben Omrane L, Mogaadi M, Khomsi WD, Zidi A, Hammou A. PEDIATRIC HEAD CT EXPOSURE DOSES IN TUNISIA: A PILOT STUDY TOWARDS THE ESTABLISHMENT OF NATIONAL DIAGNOSTIC REFERENCE LEVELS. RADIATION PROTECTION DOSIMETRY 2018; 182:241-251. [PMID: 29912455 DOI: 10.1093/rpd/ncy055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
The purpose of this study was to assess and analyze the radiation doses during head pediatric CT from different CT units within six Tunisian hospitals representing different geographic regions in order to optimize the dose given and minimize the radiology risk to this category of patients and towards the derivation of national diagnostic reference levels. Patient data and exposure parameters were collected for four age groups (<1, 1-5, 5-10 and 10-15 y). Clinical protocols and exposure settings were analyzed. Doses were collected in terms of CTDIvol and DLP values. Effective and Organ doses to specific radiosensitive organs were estimated using the Monte Carlo simulation software 'Impact CTDosimetry'. Results showed large variations in CT protocols and doses between different radiology departments. CTDIvol and DLP values demonstrated a broad range between the CT units and between the axial and helical scan techniques in the same unit. CTDI vol values were estimated to be 24.9, 31.7, 45.5 and 47.8 mGy for <1, 1-5, 5-10 and 10-15 y age groups, respectively. In term of DLP, median values were ~346, 528, 824, 897 mGy cm for the same age groups, respectively. Effective dose ranged from 1.4 to 5 mSv. Dose values were comparable with those reported in the literature. The study shows an evident need for continuous training of staff in radiation protection concepts, especially within the regional hospitals, emphasizes the importance of the production and the update of recommendations and good practice guidelines using interdisciplinary working groups and opens the way for the establishment of national DRLs.
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Affiliation(s)
- Abir Bouaoun
- University of Tunis El Manar, Higher Institute of Medical Technologies of Tunis (ISTMT), LR13ES07 Laboratory of Biophysics and Medical Technologies, Tunis, Tunisia
| | | | | | | | - Asma Zidi
- National Center of Radiation Protection, Tunis, Tunisia
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Yamazaki D, Miyazaki O, Takei Y, Matsubara K, Shinozaki M, Shimada Y, Suzuki S, Muramatsu Y. USEFULNESS OF SIZE-SPECIFIC DOSE ESTIMATES IN PEDIATRIC COMPUTED TOMOGRAPHY: REVALIDATION OF LARGE-SCALE PEDIATRIC CT DOSE SURVEY DATA IN JAPAN. RADIATION PROTECTION DOSIMETRY 2018; 179:254-262. [PMID: 29216387 DOI: 10.1093/rpd/ncx268] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 11/14/2017] [Indexed: 06/07/2023]
Abstract
The objective of this research is to calculate the organ equivalent dose and effective dose from the scanning conditions at 165 centers in Japan using computed tomography (CT) Dose software and compare the results with the CT dose index volume (CTDIvol), dose length product (DLP) and size-specific dose estimates (SSDE) to validate the usefulness of SSDE. The CTDIvol and DLP were significantly lower in infants than in children (p < 0.05). No significant differences were found in the bone marrow equivalent dose and effective dose for the torso between infants and children (p > 0.05), and the bone marrow equivalent dose and effective dose for the head were higher in infants than children (p < 0.05). No significant difference was found in SSDE for the torso between infants and children (p > 0.05). Organ equivalent and effective doses for head CT scans are higher in infants than in children (I/P ratio ≥ 1). The I/P ratios of CTDIvol and DLP for chest and abdominal CT scans are also higher in Japan than in other countries. CTDIvol and DLP are not accurate when used as a dose index, and SSDE was considered suitable for dose assessment of the torso. However, for head CT in infants, a further reduction in radiation exposure is required.
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Affiliation(s)
- Daisuke Yamazaki
- Department of Radiology, Center Hospital of the National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | | | - Yasutaka Takei
- Department of Radiological Technology, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288 Matsushima, Kurashiki, Okayama701-0193, Japan
| | - Kosuke Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
| | - Masafumi Shinozaki
- Department of Radiology, Center Hospital of the National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
| | - Yoshiya Shimada
- Medical Exposure Research Project, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba263-8555, Japan
| | - Shoichi Suzuki
- Faculty of Radiological Technology, School of Health Sciences, Fujita Health University, 1-98, Dengaku-gakubo, Kutsukake, Toyoake, Aichi 470-1192, Japan
| | - Yoshihisa Muramatsu
- Department of Radiology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
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Bagherzadeh S, Jabbari N, Khalkhali HR. Estimation of lifetime attributable risks (LARs) of cancer associated with abdominopelvic radiotherapy treatment planning computed tomography (CT) simulations. Int J Radiat Biol 2018. [PMID: 29528791 DOI: 10.1080/09553002.2018.1450536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE The present study attempts to calculate organ-absorbed and effective doses for cancer patients to estimate the possible cancer induction and cancer mortality risks resulting from 64-slice abdominopelvic computed tomography (CT) simulations for radiotherapy treatment planning (RTTP). MATERIAL AND METHODS A group of 70 patients, who underwent 64-slice abdominopelvic CT scan for RTTP, voluntarily participated in the present study. To calculate organ and effective doses in a standard phantom of 70 kg, the collected dosimetric parameters were used with the ImPACT CT Patient Dosimetry Calculator. Patient-specific organ dose and effective dose were calculated by applying related correction factors. For the estimation of lifetime attributable risks (LARs) of cancer incidence and cancer-related mortality, doses in radiosensitive organs were converted to risks based on the data published in Biological Effects of Ionizing Radiation VII (BEIR VII). RESULTS The mean ± standard deviation (SD) of the effective dose for males and females were 13.87 ± 2.37 mSv (range: 9.25-18.82 mSv) and 13.04 ± 3.42 mSv (range: 6.99-18.37 mSv), respectively. The mean ± SD of LAR of cancer incidence was 35.34 ± 13.82 cases in males and 34.49 ± 9.63 cases in females per 100,000 persons. The LAR of cancer mortality had the mean ± SD value of 15.38 ± 4.25 and 16.72 ± 3.87 cases per 100,000 persons in males and females respectively. CONCLUSION Increase in the LAR of cancer occurrence and mortality due to abdominopelvic treatment planning CT simulation is noticeable and should be considered.
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Affiliation(s)
- Saeed Bagherzadeh
- a Department of Medical Physics, School of Medicine , Urmia University of Medical Sciences , Urmia , Iran
| | - Nasrollah Jabbari
- b Solid Tumor Research Center , Urmia University of Medical Sciences , Urmia , Iran
| | - Hamid Reza Khalkhali
- c Patient Safety Research Center, Department of Biostatistics and Epidemiology , Urmia University of Medical Sciences , Urmia , Iran
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Accuracy of iodine quantification in dual-layer spectral CT: Influence of iterative reconstruction, patient habitus and tube parameters. Eur J Radiol 2018; 102:83-88. [PMID: 29685549 DOI: 10.1016/j.ejrad.2018.03.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 02/12/2018] [Accepted: 03/03/2018] [Indexed: 12/30/2022]
Abstract
PURPOSE Evaluation of the influence of iterative reconstruction, tube settings and patient habitus on the accuracy of iodine quantification with dual-layer spectral CT (DL-CT). MATERIAL AND METHODS A CT abdomen phantom with different extension rings and four iodine inserts (1, 2, 5 and 10 mg/ml) was scanned on a DL-CT. The phantom was scanned with tube-voltages of 120 and 140 kVp and CTDIvol of 2.5, 5, 10 and 20 mGy. Reconstructions were performed for eight levels of iterative reconstruction (i0-i7). Diagnostic dose levels are classified depending on patient-size and radiation dose. RESULTS Measurements of iodine concentration showed accurate and reliable results. Taking all CTDIvol-levels into account, the mean absolute percentage difference (MAPD) showed less accuracy for low CTDIvol-levels (2.5 mGy: 34.72%) than for high CTDIvol-levels (20 mGy: 5.89%). At diagnostic dose levels, accurate quantification of iodine was possible (MAPD 3.38%). Level of iterative reconstruction did not significantly influence iodine measurements. Iodine quantification worked more accurately at a tube voltage of 140 kVp. Phantom size had a considerable effect only at low-dose-levels; at diagnostic dose levels the effect of phantom size decreased (MAPD <5% for all phantom sizes). CONCLUSION With DL-CT, even low iodine concentrations can be accurately quantified. Accuracies are higher when diagnostic radiation doses are employed.
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Straight leg elevation to rule out pelvic injury. Injury 2018; 49:279-283. [PMID: 29132904 DOI: 10.1016/j.injury.2017.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 09/12/2017] [Accepted: 10/07/2017] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Pelvic x-ray is frequently used as a screening tool during initial assessment of injured patients. However routine use in the awake and alert blunt trauma patient may be questioned due to low yield. We propose a clinical tool that may avoid unnecessary imaging by examining whether the ability to straight leg raise, without pain, can rule out pelvic injury. METHODS We conducted a prospective cohort study with the exposure variables of ability to straight leg raise and presence of pain on doing so, and presence of pelvic fracture on x-ray as the primary outcome variable. RESULTS Of the 328 participants, 35 had pelvic fractures, and of these 32 were either unable to straight leg raise, or had pain on doing so, with a sensitivity of 91.43% (95% CI: 76.94-98.2%) and a negative predictive value of 98.57% (95% CI: 95.88-99.70%). The 3 participants with a pelvic fracture who could straight leg raise with no pain, all had a GCS of less than 15, and therefore, among the sub-group of patients with GCS15, a 100% sensitivity and 100% negative predictive value for straight leg raise with no pain to rule out pelvic fracture was demonstrated. CONCLUSION Among awake, alert patients, painless straight leg raise can exclude pelvic fractures and be incorporated into initial examination during reception and resuscitation of injured patients.
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Can Clinical Findings Predict Orbital Fractures and Treatment Decisions in Patients With Orbital Trauma? Derivation of a Simple Clinical Model. J Craniofac Surg 2017; 28:e661-e667. [DOI: 10.1097/scs.0000000000003823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Lemon JA, Phan N, Boreham DR. Single CT Scan Prolongs Survival by Extending Cancer Latency inTrp53Heterozygous Mice. Radiat Res 2017; 188:505-511. [DOI: 10.1667/rr14576.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Jennifer A. Lemon
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, Canada, P3E 2C6
| | - Nghi Phan
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Canada, L8S 4K1
| | - Douglas R. Boreham
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, Canada, P3E 2C6
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15
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Matsunaga Y, Kawaguchi A, Kobayashi M, Suzuki S, Asada Y, Ito K, Chida K. Fetal dose conversion factor for fetal computed tomography examinations: A mathematical phantom study. J Appl Clin Med Phys 2017; 18:330-335. [PMID: 28799286 PMCID: PMC5874942 DOI: 10.1002/acm2.12154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/15/2017] [Accepted: 06/26/2017] [Indexed: 11/12/2022] Open
Abstract
This study aimed to examine the relationship between fetal dose and the dose-length product, and to evaluate the impact of the number of rotations on the fetal doses and maternal effective doses using a 320-row multidetector computed tomography unit in a wide-volume mode. The radiation doses for the pregnant woman and the fetus were estimated using ImPACT CT Patient Dosimetry Calculator software for scan lengths ranging from 176 to 352 mm, using a 320-row unit in a wide-volume mode and an 80-row unit in a helical scanning mode. In the 320-row unit, the fetal doses in all scan lengths ranged from 3.51 to 6.52 mGy; the maternal effective doses in all scan lengths ranged from 1.05 to 2.35 mSv. In the 80-row unit, the fetal doses in all scan lengths ranged from 2.50 to 3.30 mGy; the maternal effective doses in all scan lengths ranged from 0.83 to 1.68 mSv. The estimated conversion factors from the dose-length product (mGy・cm) to fetal doses (mGy) for the 320-row unit in wide-volume mode and the 80-row unit in helical scanning mode were 0.06 and 0.05 (cm-1 ) respectively. While using a 320-row MDCT unit in a wide-volume mode, operators must take into account the number of rotations, the beam width as automatically determined by the scanner, the placement of overlap between volumetric sections, and the ratio of overlapping volumetric sections.
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Affiliation(s)
- Yuta Matsunaga
- Graduate school of MedicineTohoku UniversityAoba‐ku, SendaiJapan
- Department of ImagingNagoya Kyoritsu HospitalNagoyaJapan
| | - Ai Kawaguchi
- Graduate school of MedicineTohoku UniversityAoba‐ku, SendaiJapan
- Department of RadiologyTOYOTA Memorial HospitalToyotaJapan
| | | | - Shoichi Suzuki
- School of Health SciencesFujita Health UniversityToyoakeJapan
| | - Yasuki Asada
- School of Health SciencesFujita Health UniversityToyoakeJapan
| | - Kiyoshi Ito
- Department of Disaster Obstetrics and GynecologyInternational Research Institute of Disaster Science (IRIDeS)Tohoku UniversityAoba‐ku, SendaiJapan
| | - Koichi Chida
- Graduate school of MedicineTohoku UniversityAoba‐ku, SendaiJapan
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16
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Alqahtani MS, Lees JE, Bugby SL, Samara-Ratna P, Ng AH, Perkins AC. Design and implementation of a prototype head and neck phantom for the performance evaluation of gamma imaging systems. EJNMMI Phys 2017; 4:19. [PMID: 28685477 PMCID: PMC5500602 DOI: 10.1186/s40658-017-0186-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/26/2017] [Indexed: 11/15/2022] Open
Abstract
Background A prototype anthropomorphic head and neck phantom has been designed to simulate the adult head and neck anatomy including some internal organs and tissues of interest, such as thyroid gland and sentinel lymph nodes (SLNs). The design of the head and neck phantom includes an inner jig holding the simulated SLNs and thyroid gland. The thyroid gland structure was manufactured using three-dimensional (3D) printing taking into consideration the morphology and shape of a healthy adult thyroid gland. Result The head and neck phantom was employed to simulate a situation where there are four SLNs distributed at two different vertical levels and at two depths within the neck. Contrast to noise ratio (CNR) calculations were performed for the detected SLNs at an 80 mm distance between both pinhole collimators (0.5 and 1.0 mm diameters) and the surface of the head and neck phantom with a 100 s acquisition time. The recorded CNR values for the simulated SLNs are higher when the hybrid gamma camera (HGC) was fitted with the 1.0 mm diameter pinhole collimator. For instance, the recorded CNR values for the superficially simulated SLN (15 mm depth) containing 0.1 MBq of 99mTc using 0.5 and 1.0 mm diameter pinhole collimators are 6.48 and 16.42, respectively (~87% difference). Gamma and hybrid optical images were acquired using the HGC for the simulated thyroid gland. The count profiles through the middle of the simulated thyroid gland images provided by both pinhole collimators were obtained. The HGC could clearly differentiate the individual peaks of both thyroid lobes in the gamma image produced by the 0.5-mm pinhole collimator. In contrast, the recorded count profile for the acquired image using the 1.0-mm-diameter pinhole collimator showed broader peaks for both lobes, reflecting the degradation of the spatial resolution with increasing the diameter of the pinhole collimator. Conclusions This anthropomorphic head and neck phantom provides a valuable tool for assessing the imaging ability of gamma cameras used for imaging the head and neck region. The standardisation of test phantoms for SFOV gamma systems will provide an opportunity to collect data across various medical centres. The phantom described is cost effective, reproducible, flexible and anatomically representative.
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Affiliation(s)
- Mohammed S Alqahtani
- Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK. .,Radiological Sciences Department, College of Applied Medical Sciences, King Khalid University, Zip code 61481, Abha, 3665, Kingdom of Saudi Arabia.
| | - John E Lees
- Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
| | - Sarah L Bugby
- Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
| | - Piyal Samara-Ratna
- Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
| | - Aik H Ng
- Radiological Sciences, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Alan C Perkins
- Radiological Sciences, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK.,Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, Nottingham, UK
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17
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Hill KD, Frush DP, Han BK, Abbott BG, Armstrong AK, DeKemp RA, Glatz AC, Greenberg SB, Herbert AS, Justino H, Mah D, Mahesh M, Rigsby CK, Slesnick TC, Strauss KJ, Trattner S, Viswanathan MN, Einstein AJ. Radiation Safety in Children With Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization From the Image Gently Alliance. JACC Cardiovasc Imaging 2017; 10:797-818. [PMID: 28514670 PMCID: PMC5542588 DOI: 10.1016/j.jcmg.2017.04.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 04/25/2017] [Accepted: 04/28/2017] [Indexed: 02/07/2023]
Abstract
There is a need for consensus recommendations for ionizing radiation dose optimization during multimodality medical imaging in children with congenital and acquired heart disease (CAHD). These children often have complex diseases and may be exposed to a relatively high cumulative burden of ionizing radiation from medical imaging procedures, including cardiac computed tomography, nuclear cardiology studies, and fluoroscopically guided diagnostic and interventional catheterization and electrophysiology procedures. Although these imaging procedures are all essential to the care of children with CAHD and have contributed to meaningfully improved outcomes in these patients, exposure to ionizing radiation is associated with potential risks, including an increased lifetime attributable risk of cancer. The goal of these recommendations is to encourage informed imaging to achieve appropriate study quality at the lowest achievable dose. Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making and programmatic approaches to ensure appropriate dose monitoring. Looking ahead, there is a need for standardization of dose metrics across imaging modalities, so as to encourage comparative effectiveness studies across the spectrum of CAHD in children.
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Affiliation(s)
- Kevin D Hill
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina (Image Gently Alliance representative)
| | - Donald P Frush
- Department of Radiology, Duke University Medical Center, Durham, North Carolina (Image Gently Alliance and SPR representative)
| | - B Kelly Han
- Department of Pediatric Cardiology, Children's Heart Clinic at The Children's Hospitals and Clinics of Minnesota and the Minneapolis Heart Institute, Minneapolis, Minnesota (SCCT representative)
| | - Brian G Abbott
- Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island (ASNC representative)
| | - Aimee K Armstrong
- Department of Pediatrics, Nationwide Children's Hospital, Ohio State University, Columbus, Ohio (ACC representative)
| | - Robert A DeKemp
- Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada (SNMMI representative)
| | - Andrew C Glatz
- Department of Pediatrics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania (Image Gently Alliance representative)
| | - S Bruce Greenberg
- Department of Radiology, Arkansas Children's Hospital, Little Rock, Arkansas (NASCI representative)
| | - Alexander Sheldon Herbert
- Department of Radiology, New York-Presbyterian Morgan Stanley Children's Hospital, New York, New York (ASRT representative)
| | - Henri Justino
- Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas (SCAI representative)
| | - Douglas Mah
- Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts (PACES representative)
| | - Mahadevappa Mahesh
- Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland (AAPM representative)
| | - Cynthia K Rigsby
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois; Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois (ACR representative)
| | - Timothy C Slesnick
- Department of Pediatrics, Children's Healthcare of Atlanta, Emory University School of Medicine, Atlanta, Georgia (AAP representative)
| | - Keith J Strauss
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio (Image Gently Alliance Representative)
| | - Sigal Trattner
- Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, New York (Image Gently Alliance representative)
| | - Mohan N Viswanathan
- Department of Internal Medicine, Stanford University, Stanford, California (HRS representative)
| | - Andrew J Einstein
- Division of Cardiology, Department of Medicine, and Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York (Image Gently Alliance representative).
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18
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Sato T, Saito Y, Saito N, Ooba M. [Multicenter Investigation of the Effective Dose for Whole-body CT Scanning]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2017; 73:258-266. [PMID: 28428468 DOI: 10.6009/jjrt.2017_jsrt_73.4.258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To study whether the actual radiation exposure is different between computed tomography (CT) scanners and medical centers when the same patient is scanned, we investigated the actual effective doses for a whole body (Chest-Pelvis) CT scan in a multicenter study. MATERIALS AND METHODS Data from subjects were collected using 12 CT scanners at six medical centers in Yamagata city. Effective-dose data were acquired by scanning the same phantom (ATOM Dosimetry Phantoms Model702-B) using 120 kV tube voltage. Effective doses were calculated using corrected data from a radiophotoluminescent glass dosimeter (GD-302M). GD-302M had energy- dependent issues, which needed to be corrected. Also, differences in sensitivity based on arrangement within the phantom were insignificant. RESULTS The mean effective energy was 48.6 keV (range, 42.5-55.4 keV), and the mean effective dose was 16.3 mSv (range, 8.9-26.0 mSv). The mean effective dose with a hybrid type iterative reconstruction was 10.7 mSv (range, 8.9-16.4 mSv), but the mean effective dose without any iterative reconstruction was 20.3 mSv (range, 16.2-26.0 mSv). We found an approximate linear correlation between dose length product (DLP) on operation consoles and the effective dose. CONCLUSION We suggest that the actual radiation exposure was different at each medical center when the same patient is scanned.
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Affiliation(s)
| | | | | | - Makoto Ooba
- Department of Radiology, Yamagata University Hospital
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19
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256 Slice Multi-detector Computed Tomography Thoracic Aorta Computed Tomography Angiography: Improved Luminal Opacification Using a Patient-Specific Contrast Protocol and Caudocranial Scan Acquisition. J Comput Assist Tomogr 2016; 40:964-970. [PMID: 27755255 DOI: 10.1097/rct.0000000000000456] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
CLINICAL RELEVANCE STATEMENT Caudocranial scan direction and contrast injection timing based on measured patient vessel dynamics can significantly improve arterial and aneurysmal opacification and reduce both contrast and radiation dose in the assessment of thoracic aortic aneurysms (TAA) using helical thoracic computed tomography angiography (CTA). OBJECTIVES To investigate opacification of the thoracic aorta and TAA using a caudocranial scan direction and a patient-specific contrast protocol. MATERIALS AND METHODS Thoracic aortic CTA was performed in 160 consecutive patients with suspected TAA using a 256-slice computed tomography scanner and a dual barrel contrast injector. Patients were subjected in equal numbers to one of two contrast protocols. Patient age and sex were equally distributed across both groups. Protocol A, the department's standard protocol, consisted of a craniocaudal scan direction with 100 mL of contrast, intravenously injected at a flow rate of 4.5 mL/s. Protocol B involved a caudocranial scan direction and a novel contrast formula based on patient cardiovascular dynamics, followed by 100 mL of saline at 4.5 mL/s. Each scan acquisition comprised of 120 kVp, 200 mA with modulation, temporal resolution 0.27 seconds, and pitch 0.889:1. The dose length product was measured between each protocol and data generated were compared using Mann-Whitney U nonparametric statistics. Receiver operating characteristic analysis, visual grading characteristic (VGC), and κ analyses were performed. RESULTS Mean opacification in the thoracic aorta and aneurysm measured was 24 % and 55%, respectively. The mean contrast volume was significantly lower in protocol B (73 ± 10 mL) compared with A (100 ± 1 mL) (P<0.001). The contrast-to-noise ratio demonstrated significant differences between the protocols (protocol A, 18.2 ± 12.9; protocol B, 29.7 ± 0.61; P < 0.003). Mean effective dose in protocol B (2.6 ± 0.4 mSv) was reduced by 19% compared with A (3.2 ± 0.8 mSv) (P < 0.004). Aneurysmal detectability demonstrated significant increases by receiver operating characteristic and visual grading characteristic analysis for protocol B compared with A (P < 0.02), and reader agreement increased from poor to excellent. CONCLUSIONS Significant increase in the visualization of TAAs following a caudocranial scan direction during helical thoracic CTA can be achieved using low-contrast volume based on patient-specific contrast formula.
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20
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Qi Z, Lemen LC, Lamba M, Chen HH, Samaratunga R, Mahoney M, Hendrick RE. Radiation Dose to the Breast by 64-slice CT: Effects of Scanner Model and Study Protocol. Acad Radiol 2016; 23:987-93. [PMID: 27287714 DOI: 10.1016/j.acra.2016.03.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 03/04/2016] [Accepted: 03/05/2016] [Indexed: 10/21/2022]
Abstract
RATIONALE AND OBJECTIVES This work aimed to study the effects of scanner model and study protocol on radiation dose received by breast tissues from 64-slice computed tomography (CT) studies. MATERIALS AND METHODS Four scanner models and three study protocols were used in scanning an anthropomorphic phantom with breast modules. Each protocol follows recommendations or guidelines from the American Association of Physicists in Medicine and the American College of Radiology. Twenty thermoluminescent dosimeters were placed inside the breast modules to measure breast tissue doses. Both the absolute and the normalized breast tissue doses were analyzed. RESULTS The mean glandular doses of a lung cancer screening CT, a chest/abdomen/pelvis CT, and a virtual colonoscopy CT are equivalent to less than 1, 5-7, and 1-3 two-view digital mammograms, respectively, for a standard-sized patient. The normalized breast dose differs significantly (P < 0.01) between lung cancer screening CT and chest/abdomen/pelvis CT; however, it shows less than ±10% variation among scanner models for the same protocol. In virtual colonoscopy CT, breast tissue dose decreases with the distance between local tissues to the edge of the x-ray field, although the decreasing trend varies for different scanner models and protocol settings. CONCLUSIONS When breasts are entirely included in the primary x-ray field, breast dose by 64-slice CT is mainly protocol dependent, with the normalized breast dose about 15% lower for protocols with modulated mA than for those with constant mA; when breasts are only partially included in the primary beam field, breast dose by 64-slice CT is dependent on both the scanner model and the protocol settings.
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21
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Stein PD, Matta F, Hughes PG, Hourmouzis ZN, Hourmouzis NP, Schweiss RE, Bach JA, Kazan VM, Kakish EJ, Keyes DC, Hughes MJ. Follow-up CT pulmonary angiograms in patients with acute pulmonary embolism. Emerg Radiol 2016; 23:463-7. [PMID: 27405309 DOI: 10.1007/s10140-016-1422-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/04/2016] [Indexed: 11/29/2022]
Abstract
Computed tomographic (CT) angiography is associated with a non-negligible lifetime attributable risk of cancer. The risk is considerably greater for women and younger patients. Recognizing that there are risks from radiation, the purpose of this investigation was to assess the frequency of follow-up CT angiograms in patients with acute pulmonary embolism. This was a retrospective cohort study of patients aged ≥18 years with acute pulmonary embolism seen in three emergency departments from January 2013 to December 2014. Records of all patients were reviewed for at least 14 months. Pulmonary embolism was diagnosed by CT angiography in 600 patients. At least one follow-up CT angiogram in 1 year was obtained in 141 of 600 (23.5 %). Two follow-ups in 1 year were obtained in 40 patients (6.7 %), 3 follow-ups were obtained in 15 patients (2.5 %), and 4 follow-ups were obtained in 3 patients (0.5 %). Among young women (aged ≤29 years) with pulmonary embolism, 10 of 21 (47.6 %) had at least 1 follow-up and 4 of 21 (19.0 %) had 2 or more follow-ups in 1 year. Among all patients, recurrent pulmonary embolism was diagnosed in 15 of 141 (10.6 %) on the first follow-up CT angiogram and in 6 of 40 (15.0 %) on the second follow-up. Follow-up CT angiograms were obtained in a significant proportion of patients with pulmonary embolism, including young women, the group with the highest risk. Alternative options might be considered to reduce the hazard of radiation-induced cancer, particularly in young women.
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Affiliation(s)
- Paul D Stein
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, 909 Fee Road, East Lansing, MI, 48824, USA.
| | - Fadi Matta
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, 909 Fee Road, East Lansing, MI, 48824, USA
| | - Patrick G Hughes
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, 909 Fee Road, East Lansing, MI, 48824, USA.,Department of Medical Education, Summa Akron City Hospital, Akron, OH, USA
| | - Zak N Hourmouzis
- Department of Medical Education, Summa Akron City Hospital, Akron, OH, USA
| | - Nina P Hourmouzis
- Department of Medical Education, Summa Akron City Hospital, Akron, OH, USA
| | - Robert E Schweiss
- Department of Emergency Medicine, St. Mary Mercy Hospital, Livonia, MI, USA
| | - Jennifer A Bach
- Department of Emergency Medicine, St. Mary Mercy Hospital, Livonia, MI, USA
| | - Viviane M Kazan
- Department of Emergency Medicine, University of Toledo Medical Center, Toledo, OH, USA
| | - Edward J Kakish
- Department of Emergency Medicine, University of Toledo Medical Center, Toledo, OH, USA
| | - Daniel C Keyes
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, 909 Fee Road, East Lansing, MI, 48824, USA.,Department of Emergency Medicine, St. Mary Mercy Hospital, Livonia, MI, USA
| | - Mary J Hughes
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, 909 Fee Road, East Lansing, MI, 48824, USA
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22
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Werncke T, von Falck C, Luepke M, Stamm G, Wacker FK, Meyer BC. Collimation and Image Quality of C-Arm Computed Tomography: Potential of Radiation Dose Reduction While Maintaining Equal Image Quality. Invest Radiol 2016; 50:514-21. [PMID: 25867655 DOI: 10.1097/rli.0000000000000158] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to assess the potential for radiation dose reduction in collimated C-arm computed tomography (CACT) while maintaining the image quality of the full field of view (FFOV) acquisition. MATERIAL AND METHODS A whole-body anthropomorphic phantom representing a 70-kg male was used in this study. The upper abdomen of the phantom was imaged using an angiographic system (Artis Zeego Q; Siemens Healthcare, Germany) with either the standard detector radiation dose level (RDL; D100, 360 nGy) or 14 experimental reduced RDLs ranging from 95% (D95, 342 nGy) to 30% D100 (D30, 108 nGy). Either the FFOV (craniocaudal coverage, 18 cm) or a collimated field of view (CFOV; craniocaudal coverage, 6 cm) was applied. The organ dose was measured using thermoluminescence detector dosimetry, and the mean effective dose was computed according to the recommendations by the International Commission on Radiological Protection Publication 103. To compare the CFOV and the FFOV data sets, image quality was assessed in terms of high- and low-contrast resolution by calculating the modulation transfer function using the wire method as well as the image noise, signal-to-noise ratio, and contrast-to-noise ratio using a low-contrast insert placed in the upper abdomen (Δ50 HU). RESULTS Collimated imaging (CFOV) covering 33% of the FFOV led to an increase in the x-ray tube output of 152% for CFOV (D100; FFOV, 95.5 mGy; CFOV, 147.7 mGy) to maintain the detector dose. The mean effective dose of D100 was 6.0 mSv (male) and 6.2 mSv (female) for the FFOV and 3.7 mSv (male) and 4.1 mSv (female) for the CFOV. High-contrast resolution was comparable for all acquisition protocols (mean 10% modulation transfer function ± 95% confidence interval; FFOV, 8.8 ± 0.1 line pairs/cm; CFOV, 8.8 ± 0.1 line pairs/cm). Low-contrast resolution was superior for the CFOV compared with that for the FFOV for each RDL (D100; image noise: FFOV, 34 ± 2 HU; CFOV, 22 ± 1 HU; contrast-to-noise ratio: FFOV, 1.3 ± 0.2; CFOV, 1.8 ± 0.3). Low-contrast resolution of the standard (D100) FFOV acquisition was achieved for the CFOV at 84% D100 of the FFOV and 54% D100 of the CFOV. Therefore, collimation up to 33% of the FFOV combined with the lower detector dose allows overall reduction of a patient's radiation exposure to 33% × 84% = 28% compared with FFOV acquisition. In the upper abdomen, this results in a nearly 50% reduction of the mean effective radiation dose (male, 2.0 mSv; female, 2.2 mSv) without loss of image quality compared with the standard FFOV acquisition. CONCLUSIONS Craniocaudal collimation in CACT should be used whenever possible to increase the image quality and reduce the patient's overall radiation exposure. Therefore, new smart acquisition protocols are required for collimated CACT to improve the trade-off between radiation exposure and image quality requirements considering the collimation used.
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Affiliation(s)
- Thomas Werncke
- From the *Institute of Diagnostic and Interventional Radiology, Hannover Medical School; and †University of Veterinary Medicine, Hannover Institute for General Radiology and Medical Physics, Hannover, Germany
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Fluoroscopy-guided Percutaneous Endoscopic Gastrostomy in Children. Surg Laparosc Endosc Percutan Tech 2016; 26:167-70. [DOI: 10.1097/sle.0000000000000255] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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24
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Mehdizadeh Naderi S, Sina S, Karimipoorfard M, Lotfalizadeh F, Entezarmahdi M, Moradi H, Faghihi R. Design and fabrication of a multipurpose thyroid phantom for medical dosimetry and calibration. RADIATION PROTECTION DOSIMETRY 2016; 168:503-508. [PMID: 26124260 DOI: 10.1093/rpd/ncv359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 05/27/2015] [Indexed: 06/04/2023]
Abstract
A multipurpose anthropomorphic neck phantom was designed and fabricated for use in medical applications. The designed neck phantom is composed of seven elliptic cylindrical slices with a semi-major axis of 14 cm and a semi-minor axis of 12.5 cm, each having the thickness of 2 cm. The thyroid gland, bony part of the neck, and the windpipe were also built inside the neck phantom. For the purpose of medical dosimetry, some holes were drilled inside the phantom to accommodate the thermoluminescence dosemeters with different shapes and dimensions. For testing the quality of images in nuclear medicine, the thyroid gland was built separately to accommodate the radioactive iodine. Finally, the nuclear medicine images were obtained by inserting (131)I in both male and female thyroid parts.
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Affiliation(s)
| | - Sedigheh Sina
- Radiation Research Center, Shiraz University, Shiraz, Iran
| | | | | | - Mohammad Entezarmahdi
- Department of Nuclear Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Department of Radiation in Medicine Engineering, Shahid Beheshti University, Tehran, Iran
| | - Hamed Moradi
- Department of Ray-Medical Engineering, Shiraz University, Shiraz, Iran
| | - Reza Faghihi
- Department of Ray-Medical Engineering, Shiraz University, Shiraz, Iran
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25
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Santos J, Foley S, Paulo G, McEntee MF, Rainford L. The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography. Pediatr Radiol 2015; 45:1814-22. [PMID: 26242810 DOI: 10.1007/s00247-015-3398-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 03/28/2015] [Accepted: 06/01/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. OBJECTIVE To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. MATERIALS AND METHODS Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. RESULTS Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). CONCLUSION Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings.
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Affiliation(s)
- Joana Santos
- Instituto Politécnico de Coimbra, ESTESC, DMIR, Rua 5 de Outubro, S. Martinho do Bispo, 3046-854, Coimbra, Portugal.
| | - Shane Foley
- School of Medicine & Medical Science, Health Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
| | - Graciano Paulo
- Instituto Politécnico de Coimbra, ESTESC, DMIR, Rua 5 de Outubro, S. Martinho do Bispo, 3046-854, Coimbra, Portugal
| | - Mark F McEntee
- Faculty of Health Sciences, Cumberland Campus, The University of Sydney, Sydney, Australia
| | - Louise Rainford
- School of Medicine & Medical Science, Health Science Centre, University College Dublin, Belfield, Dublin 4, Ireland
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26
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Takahashi F, Sato K, Endo A, Ono K, Ban N, Hasegawa T, Katsunuma Y, Yoshitake T, Kai M. Numerical Analysis of Organ Doses Delivered During Computed Tomography Examinations Using Japanese Adult Phantoms with the WAZA-ARI Dosimetry System. HEALTH PHYSICS 2015; 109:104-112. [PMID: 26107430 DOI: 10.1097/hp.0000000000000299] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A dosimetry system for computed tomography (CT) examinations, named WAZA-ARI, is being developed to accurately assess radiation doses to patients in Japan. For dose calculations in WAZA-ARI, organ doses were numerically analyzed using average adult Japanese male (JM) and female (JF) phantoms with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the photon energy distribution of emitted photons and dose profiles on the table for some multi-detector row CT (MDCT) devices. Numerical analyses using a source model in PHITS could specifically take into account emissions of x rays from the tube to the table with attenuation of photons through a beam-shaping filter for each MDCT device based on the experiment results. The source model was validated by measuring the CT dose index (CTDI). Numerical analyses with PHITS revealed a concordance of organ doses with body sizes of the JM and JF phantoms. The organ doses in the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculations in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model (THRA1 phantom). The results imply that numerical analyses using the Japanese phantoms and specified source models can give reasonable estimates of dose for MDCT devices for typical Japanese adults.
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Affiliation(s)
- Fumiaki Takahashi
- *Japan Atomic Energy Agency, †Tokyo Healthcare University, ‡Tokai University Oiso Hospital, §Tokai University Hospital, **Shin-Beppu Hospital, ††Oita University of Nursing and Health Sciences
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27
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Sulieman A, Tammam N, Alzimami K, Elnour AM, Babikir E, Alfuraih A. Dose reduction in chest CT examination. RADIATION PROTECTION DOSIMETRY 2015; 165:185-189. [PMID: 25836698 DOI: 10.1093/rpd/ncv123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Computed tomography (CT) examinations involve relatively high doses to patients. The objectives of this study were to optimise the radiation dose for patient during CT chest scan and to estimate the lifetime cancer risk. A total of 50 patients were studied: control group (A) (38 patients) and optimisation group (B) (12 patients). The optimisation protocol was based on CT pitch increment and lowering tube current. The mean volume CT dose index (CTDI vol) was 21.17 mGy and dose length product (DLP) was 839.0 mGy cm for Group A, and CTDI vol was 8.3 mGy and DLP was 339.7 for Group B. The overall cancer risk was estimated to be 8.0 and 3.0 cancer incidence per million for Groups A and B, respectively. The patient dose optimisation during CT chest was investigated. Lowering tube current and pitch increment achieved a radiation dose reduction of up to 60 % without compromising the diagnostic findings.
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Affiliation(s)
- A Sulieman
- Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Alkharj, Kingdom of Saudi Arabia College of Medical Radiologic Science, Sudan University of Science and Technology, Khartoum, Sudan
| | - N Tammam
- College of Medical Radiologic Science, Sudan University of Science and Technology, Khartoum, Sudan
| | - K Alzimami
- Radiological Sciences Department, College of Applied Sciences, King Saud University, Riyadh, Saudi Arabia
| | - A M Elnour
- College of Medical Radiologic Science, Sudan University of Science and Technology, Khartoum, Sudan
| | - E Babikir
- Radiological Sciences Department, College of Applied Sciences, King Saud University, Riyadh, Saudi Arabia
| | - A Alfuraih
- Radiological Sciences Department, College of Applied Sciences, King Saud University, Riyadh, Saudi Arabia
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Kamei O, Ojima M, Yoshitake T, Ono K, Nishijima K, Kai M. Calculating patient-specific organ doses from adult body CT scans by Monte Carlo analysis using male-individual voxel phantoms. HEALTH PHYSICS 2015; 108:44-52. [PMID: 25437519 DOI: 10.1097/hp.0000000000000170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Computed tomography (CT) dose calculators such as the WAZA-ARI are useful for estimating the radiation dose from CT examination. This study determined correction coefficients for estimating organ doses to patients of any size attended to in daily clinical practice. To this end, the authors constructed voxel phantoms based on the CT images of patients of different size and simulated radiation transport in CT examinations to obtain organ doses using Monte Carlo simulation. The results show that the linear relationship between effective diameter and organ dose can predict patient-specific organ doses. The effective diameter-based prediction can provide accuracy within an error of ±10%, whereas an error of >20% was observed only in the liver and bladder. These results may contribute to practical irradiation dose calculation from a CT examination depending on individual patient size within a certain degree of accuracy.
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Affiliation(s)
- Osamu Kamei
- *Graduate school, Oita University of Nursing and Health Sciences, 2944-9 Megusuno, Oita city, Oita 870-1201, Japan; †Department of Health Sciences, Oita University of Nursing and Health Sciences, 2944-9 Megusuno, Oita city, Oita 870-1201, Japan; ‡Shin-Beppu Hospital, 3898 Tsurumi, Beppu-shi, Oita 874-0833, Japan; §Tokyo Healthcare University, 2-5-23 Higashigaoka, Meguro-ku, Tokyo 152-8558, Japan; **Oia Prefectural Hospital, 476 Bunyou, Oita-shi, Oita 870-851, Japan
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Santos J, Batista MDC, Foley S, Paulo G, McEntee MF, Rainford L. Paediatric CT optimisation utilising Catphan® 600 and age-specific anthropomorphic phantoms. RADIATION PROTECTION DOSIMETRY 2014; 162:586-596. [PMID: 24567497 DOI: 10.1093/rpd/ncu018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The purpose of the study is to perform phantom-based optimisation of paediatric computed tomography (CT) protocols and quantify the impact upon radiation dose and image noise levels. The study involved three Portuguese paediatric centres. Currently employed scanning protocols for head and chest examinations and combinations of exposure parameters were applied to a Catphan(®)600 phantom to review the CT dose impact. Contrast-noise ratio (CNR) was quantified using Radia Diagnostic(®) tool. Imaging parameters, returning similar CNRs (<1) and dose savings were applied to three paediatric anthropomorphic phantoms. OsiriX software based on standard deviation pixel values facilitated image noise analysis. Currently employed protocols and age categorisation varied between centres. Manipulation of exposure parameters facilitated mean dose reductions of 33 and 28 % for paediatric head and chest CT examinations, respectively. The majority of the optimised CT examinations resulted in image noise similar to currently employed protocols. Dose reductions of up to 33 % were achieved with image quality maintained.
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Affiliation(s)
- Joana Santos
- Instituto Politécnico de Coimbra, ESTESC-Coimbra Health School, Radiologia, Rua 5 de Outubro, S. Martinho do Bispo, 3046-854 Coimbra, Portugal
| | - Maria do Carmo Batista
- Departamento de Física Médica, Dr. Campos Costa, Consultório de Tomografia Computorizada S.A, Porto, Portugal
| | - Shane Foley
- School of Medicine & Medical Science, Health Science Centre, University College Dublin, Belfield Dublin 4, Ireland
| | - Graciano Paulo
- Instituto Politécnico de Coimbra, ESTESC-Coimbra Health School, Radiologia, Rua 5 de Outubro, S. Martinho do Bispo, 3046-854 Coimbra, Portugal
| | - Mark F McEntee
- Faculty of Health Sciences, The University of Sydney, Cumberland Campus, Sydney, Australia
| | - Louise Rainford
- School of Medicine & Medical Science, Health Science Centre, University College Dublin, Belfield Dublin 4, Ireland
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Arandjic D, Ciraj-Bjelac O, Hadnadjev D, Stojanovic S, Bozovic P, Ceklic S, Lazarevic D. Radiation doses in adult computed tomography practice in Serbia: initial results. RADIATION PROTECTION DOSIMETRY 2014; 162:135-138. [PMID: 25063787 DOI: 10.1093/rpd/ncu245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This work presents initial data on radiation doses in adult computed tomography (CT) in Serbia. Data were collected in terms of CT dose index (CTDIvol) and dose length product (DLP) values for head, chest and abdomen examination. The range of CTDIvol values was found to be 53-98, 11-34 and 8.5-227 mGy whereas for DLP was 803-1066, 350-845 and 1066-3078 mGy cm(-1) for head, chest and abdomen examination, respectively. Except for abdomen on one CT unit, all estimated values were in line with the reported data. This work also presents simple method on how to reduce radiation doses when scanning head. Using axial (step-and-shot) instead of helical mode and decreasing tube current-time product leads to significant dose reduction. CTDIvol was decreased by 20 % whereas DLP was reduced for a factor 2.
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Affiliation(s)
- Danijela Arandjic
- Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia School of Electrical Engineering, University of Belgrade, Belgrade, Serbia
| | - Olivera Ciraj-Bjelac
- Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia School of Electrical Engineering, University of Belgrade, Belgrade, Serbia
| | | | | | - Predrag Bozovic
- Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia School of Electrical Engineering, University of Belgrade, Belgrade, Serbia
| | - Sandra Ceklic
- Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia School of Electrical Engineering, University of Belgrade, Belgrade, Serbia
| | - Djordje Lazarevic
- Vinca Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia School of Electrical Engineering, University of Belgrade, Belgrade, Serbia
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Kashcheev VV, Pryakhin EA, Menyaylo AN, Chekin SY, Ivanov VK. Comparing risk estimates following diagnostic CT radiation exposures employing different methodological approaches. HEALTH PHYSICS 2014; 106:806-811. [PMID: 24776915 DOI: 10.1097/hp.0000000000000096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The current study has two aims: the first is to quantify the difference between radiation risks estimated with the use of organ or effective doses, particularly when planning pediatric and adult computed tomography (CT) examinations. The second aim is to determine the method of calculating organ doses and cancer risk using dose-length product (DLP) for typical routine CT examinations. In both cases, the radiation-induced cancer risks from medical CT examinations were evaluated as a function of gender and age. Lifetime attributable risk values from CT scanning were estimated with the use of ICRP (Publication 103) risk models and Russian national medical statistics data. For populations under the age of 50 y, the risk estimates based on organ doses usually are 30% higher than estimates based on effective doses. In older populations, the difference can be up to a factor of 2.5. The typical distributions of organ doses were defined for Chest Routine, Abdominal Routine, and Head Routine examinations. The distributions of organ doses were dependent on the anatomical region of scanning. The most exposed organs/tissues were thyroid, breast, esophagus, and lungs in cases of Chest Routine examination; liver, stomach, colon, ovaries, and bladder in cases of Abdominal Routine examination; and brain for Head Routine examinations. The conversion factors for calculation of typical organ doses or tissues at risk using DLP were determined. Lifetime attributable risk of cancer estimated with organ doses calculated from DLP was compared with the risk estimated on the basis of organ doses measured with the use of silicon photodiode dosimeters. The estimated difference in LAR is less than 29%.
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Affiliation(s)
- Valery V Kashcheev
- *Federal State Institution Medical Radiological Research Center of the Russian Ministry of Health, 4 Korolyov str., Obninsk, Kaluga Region, 249036, Russia
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Gorycki T, Kamiński K, Studniarek M, Szlęzak P, Szumska A. Distribution of the radiation dose in multislice computer tomography of the chest - phantom study. Pol J Radiol 2014; 79:75-8. [PMID: 24744819 PMCID: PMC3990109 DOI: 10.12659/pjr.889951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 12/12/2013] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The most commonly used form of reporting doses in multislice computed tomography involves a CT dose index per slice and dose-length product for the whole series. The purpose of this study was to analyze the actual dose distribution in routine chest CT examination protocols using an antropomorphic phantom. MATERIAL/METHODS We included in the analysis readings from a phantom filled with thermoluminescent detectors (Art Phantom Canberra) during routine chest CT examinations (64 MDCT TK LIGHT SPEED GE Medical System) performed using three protocols: low-dose, helical and angio-CT. RESULTS Mean dose values (mSv) reported from anterior parts of the phantom sections in low-dose/helical/angio-CT protocols were as follows: 3.74; 16.95; 30.17; from central parts: 3.18; 14.15; 26.71; from posterior parts: 3.01; 12.47; 24.98 respectively. Correlation coefficients for mean doses registered in anterior parts of the phantom between low-dose/helical, low-dose/angio-CT and helical/angio-CT protocols were 0.49; 0.63; 0.36; from central parts: 0.73; 0.66; 0.83, while in posterior parts values were as follows: 0.06; 0.21; 0.57. CONCLUSIONS The greatest doses were recorded in anterior parts of all phantom sections in all protocols in reference to largest doses absorbed in the anterior part of the chest during CT examination. The doses were decreasing from anterior to posterior parts of all sections. In the long axis of the phantom, in all protocols, lower doses were measured in the upper part of the phantom and at the very lowest part.
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Affiliation(s)
- Tomasz Gorycki
- Department of Radiology, Medical University of Gdańsk, Gdańsk, Poland ; Department of Imaging Diagnostics and Interventional Radiology, Franciszek Łukaszczyk Oncology Center in Bydgoszcz, Bydgoszcz, Poland
| | - Kamil Kamiński
- Department of Imaging Diagnostics and Interventional Radiology, Franciszek Łukaszczyk Oncology Center in Bydgoszcz, Bydgoszcz, Poland
| | - Michał Studniarek
- Department of Radiology, Medical University of Gdańsk, Gdańsk, Poland ; Department of Imaging Diagnostics and Interventional Radiology, Franciszek Łukaszczyk Oncology Center in Bydgoszcz, Bydgoszcz, Poland
| | - Przemysław Szlęzak
- Department of Imaging Diagnostics and Interventional Radiology, Franciszek Łukaszczyk Oncology Center in Bydgoszcz, Bydgoszcz, Poland
| | - Agnieszka Szumska
- Individual and Environmental Dosimetry Laboratory, Henryk Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
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Optimization of computed tomography (CT) arthrography of hip for the visualization of cartilage: an in vitro study. Skeletal Radiol 2014; 43:169-78. [PMID: 24281772 DOI: 10.1007/s00256-013-1759-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 10/11/2013] [Accepted: 10/13/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We sought to optimize the kilovoltage, tube current, and the radiation dose of computed tomographic arthrography of the hip joint using in vitro methods. MATERIALS AND METHODS A phantom was prepared using a left femoral head harvested from a patient undergoing total hip arthroplasty and packed in a condom filled with iodinated contrast. The right hip joint of a cadaver was also injected with iodinated contrast. The phantom and the cadaver were scanned using different values of peak kilovoltage (kVp) and tube current (milliamp seconds, mAs). Three different regions of interest (ROI) were drawn in the cartilage, subchondral bone plate, and intraarticular contrast. The attenuation values, contrast/noise ratio (CNR), and effective dose were calculated. Two independent observers classified the quality of the contrast-cartilage interface and the cartilage-subchondral bone plate interface as (1) diagnostic quality or (2) nondiagnostic quality. RESULTS Contrast, cartilage, and subchondral bone plate attenuation values decreased at higher kVp. CNR increased with both kVp and mAs. The qualitative analysis showed that in both phantom and cadaver, at 120 kVp and 50 mAs, the contrast-cartilage and cartilage-subchondral bone plate interfaces were of diagnostic quality, with an effective dose decreased to 0.5 MSv. CONCLUSIONS The absolute effective dose is not directly related to the quality of images but to the specific combination of kVp and mAs used for image acquisition. The combination of 120 kVp and 50 mAs can be suggested to decrease the dose without adversely affect the visibility of cartilage and subchondral bone plate.
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Foley SJ, McEntee MF, Rainford LA. An evaluation of in-plane shields during thoracic CT. RADIATION PROTECTION DOSIMETRY 2013; 155:439-450. [PMID: 23460031 DOI: 10.1093/rpd/nct030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The object of this study was to compare organ dose and image quality effects of using bismuth and barium vinyl in-plane shields with standard and low tube current thoracic CT protocols. A RANDO phantom was scanned using a 64-slice CT scanner and three different thoracic protocols. Thermoluminescent dosemeters were positioned in six locations to record surface and absorbed breast and lung doses. Image quality was assessed quantitatively using region of interest measurements. Scanning was repeated using bismuth and barium vinyl in-plane shields to cover the breasts and the results were compared with standard and reduced dose protocols. Dose reductions were most evident in the breast, skin and anterior lung when shielding was used, with mean reductions of 34, 33 and 10 % for bismuth and 23, 18 and 11 % for barium, respectively. Bismuth was associated with significant increases in both noise and CT attenuation values for all the three protocols, especially anteriorly and centrally. Barium shielding had a reduced impact on image quality. Reducing the overall tube current reduced doses in all the locations by 20-27 % with similar increases in noise as shielding, without impacting on attenuation values. Reducing the overall tube current best optimises dose with minimal image quality impact. In-plane shields increase noise and attenuation values, while reducing anterior organ doses primarily. Shielding remains a useful optimisation tool in CT and barium is an effective alternative to bismuth especially when image quality is of concern.
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Affiliation(s)
- S J Foley
- School of Medicine and Medical Science, University College Dublin, Dublin 4, Ireland.
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The ratio of ICRP103 to ICRP60 calculated effective doses from CT: Monte Carlo calculations with the ADELAIDE voxel paediatric model and comparisons with published values. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2013; 36:355-62. [PMID: 23860741 DOI: 10.1007/s13246-013-0211-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
Abstract
The ADELAIDE voxel model of paediatric anatomy was used with the EGSnrc Monte Carlo code to compare effective dose from computed tomography (CT) calculated with both the ICRP103 and ICRP60 definitions which are different in their tissue weighting factors and in the included tissues. The new tissue weighting factors resulted in a lower effective dose for pelvis CT (than if calculated using ICRP60 tissue weighting factors), by 6.5% but higher effective doses for all other examinations. ICRP103 calculated effective dose for CT abdomen + pelvis was higher by 4.6%, for CT abdomen (by 9.5%), for CT chest + abdomen + pelvis (by 6%), for CT chest + abdomen (by 9.6%), for CT chest (by 10.1%) and for cardiac CT (by 11.5%). These values, along with published values of effective dose from CT that were calculated for both sets of tissue weighting factors were used to determine single values for the ratio ICRP103:ICRP60 calculated effective doses from CT, for seven CT examinations. The following values for ICRP103:ICRP60 are suggested for use to convert ICRP60 calculated effective dose to ICRP103 calculated effective dose for the following CT examinations: Pelvis CT, 0.75; for abdomen CT, abdomen + pelvis CT, chest + abdomen + pelvis CT, 1.00; for chest + abdomen CT, and for chest CT. 1.15; for cardiac CT 1.25.
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Gervaise A, Teixeira P, Villani N, Lecocq S, Louis M, Blum A. CT dose optimisation and reduction in osteoarticular disease. Diagn Interv Imaging 2013; 94:371-88. [DOI: 10.1016/j.diii.2012.05.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Estimating the effective radiation dose imparted to patients by intraoperative cone-beam computed tomography in thoracolumbar spinal surgery. Spine (Phila Pa 1976) 2013; 38:E306-12. [PMID: 23238490 DOI: 10.1097/brs.0b013e318281d70b] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Observational. OBJECTIVE To estimate the radiation dose imparted to patients during typical thoracolumbar spinal surgical scenarios. SUMMARY OF BACKGROUND DATA Minimally invasive techniques continue to become more common in spine surgery. Computer-assisted navigation systems coupled with intraoperative cone-beam computed tomography (CT) represent one such method used to aid in instrumented spinal procedures. Some studies indicate that cone-beam CT technology delivers a relatively low dose of radiation to patients compared with other x-ray-based imaging modalities. The goal of this study was to estimate the radiation exposure to the patient imparted during typical posterior thoracolumbar instrumented spinal procedures, using intraoperative cone-beam CT and to place these values in the context of standard CT doses. METHODS Cone-beam CT scans were obtained using Medtronic O-arm (Medtronic, Minneapolis, MN). Thermoluminescence dosimeters were placed in a linear array on a foam-plastic thoracolumbar spine model centered above the radiation source for O-arm presets of lumbar scans for small or large patients. In-air dosimeter measurements were converted to skin surface measurements, using published conversion factors. Dose-length product was calculated from these values. Effective dose was estimated using published effective dose to dose-length product conversion factors. RESULTS Calculated dosages for many full-length procedures using the small-patient setting fell within the range of published effective doses of abdominal CT scans (1-31 mSv). Calculated dosages for many full-length procedures using the large-patient setting fell within the range of published effective doses of abdominal CT scans when the number of scans did not exceed 3. CONCLUSION We have demonstrated that single cone-beam CT scans and most full-length posterior instrumented spinal procedures using O-arm in standard mode would likely impart a radiation dose within the range of those imparted by a single standard CT scan of the abdomen. Radiation dose increases with patient size, and the radiation dose received by larger patients as a result of more than 3 O-arm scans in standard mode may exceed the dose received during standard CT of the abdomen. Understanding radiation imparted to patients by cone-beam CT is important for assessing risks and benefits of this technology, especially when spinal surgical procedures require multiple intraoperative scans.
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Sugimoto N, Aoyama T, Koyama S, Yamauchi-Kawaura C, Fujii K. Comparison of radiation doses between newborns and 6-y-old children undergoing head, chest and abdominal CT examinations: a phantom study. RADIATION PROTECTION DOSIMETRY 2013; 153:85-91. [PMID: 22645383 DOI: 10.1093/rpd/ncs085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Radiation doses in paediatric computed tomography (CT) were investigated for various types of recent CT scanners with newborn and 6-y-old phantoms in which silicon-photodiode dosemeters were implanted at various organ positions. In the head, chest and abdominal CT for the newborn phantom, doses for organs within the scan region were 21-40, 3-8 and 3-12 mGy, respectively. The corresponding doses for the child phantom were 20-37, 2-11 and 4-17 mGy, respectively. In the head, chest and abdominal CT, the effective doses were respectively 2.1-3.3, 2.0-6.0 and 2.2-10.0 mSv for the newborn, and 1.0-2.0, 1.2-6.6 and 2.9-11.8 mSv for the child. Radiation doses for the newborn were at the same levels as those for the child, excepting effective doses in head CT for the newborn, which were 1.8 times higher than those for the child.
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Affiliation(s)
- Naruto Sugimoto
- Graduate school of Medicine, Nagoya University, Daikominami, Higashi-ku, Nagoya, Japan.
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Abou El-Ghar ME, Shokeir AA, Refaie HF, El-Nahas AR. Low-dose unenhanced computed tomography for diagnosing stone disease in obese patients. Arab J Urol 2012; 10:279-83. [PMID: 26558037 PMCID: PMC4442952 DOI: 10.1016/j.aju.2012.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/25/2012] [Accepted: 02/25/2012] [Indexed: 12/02/2022] Open
Abstract
Objective To evaluate the detectability, size, location and density of urinary stones with unenhanced computed tomography (CT), using the half-radiation (low) dose (LDCT) technique, compared with the standard-dose CT (SDCT), in obese patients. Patients and methods The study included 50 patients with a body mass index of >30 kg/m2 and bilateral renal stones diagnosed with SDCT, and managed on one side. All the patients had LDCT during the follow-up and SDCT was used as a reference for comparison. Results Of the 50 patients, the right side was affected in 27 and the left side in 23. In all, 35 patients had a single stone while the remaining 15 had multiple stones. With SDCT, 95 stones were detected; there were 45 of ⩽5 mm, 46 of 6–15 mm and only four of >15 mm. LDCT barely detected three stones of <3 mm, compared with SDCT, while larger stones had the same appearance at both scans. The site of stone in the kidney or the ureter did not affect its detection on LDCT vs. SDCT. The mean stone diameter was identical in both techniques. At LDCT, all stones were detected with no difference in their number, location or density vs. SDCT. However, the tube current and radiation dose were significantly lower with LDCT. Conclusions In obese patients with stone disease, LDCT is as accurate as SDCT, while avoiding exposure of the patient to high-dose radiation.
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Affiliation(s)
- Mohamed E Abou El-Ghar
- Department of Radiology, Urology & Nephrology Center, Mansoura University, Mansoura, Egypt
| | - Ahmed A Shokeir
- Department of Urology, Urology & Nephrology Center, Mansoura University, Mansoura, Egypt
| | - Huda F Refaie
- Department of Radiology, Urology & Nephrology Center, Mansoura University, Mansoura, Egypt
| | - Ahmed R El-Nahas
- Department of Urology, Urology & Nephrology Center, Mansoura University, Mansoura, Egypt
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Prospectively ECG-triggered high-pitch spiral acquisition for cardiac CT angiography in routine clinical practice: initial results. J Thorac Imaging 2012; 27:194-201. [PMID: 21964497 DOI: 10.1097/rti.0b013e318228223f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE This study was conducted to evaluate the mode of application, image quality (IQ), and radiation exposure resulting from introduction of a prospectively electrocardiogram-triggered high-pitch cardiac computed tomography angiography (CTA) acquisition mode into routine clinical practice. MATERIALS AND METHODS A total of 42 prospectively triggered cardiac CTAs were conducted on 34 patients (11 female, 23 male; mean age 56 ± 15 y) using a high-pitch mode (pitch 3.4) on a dual-source CT. In 8 of these patients with higher heart rates or occasional premature ventricular contractions, 2 immediately subsequent CTAs were performed ("double flash protocol"). Subjective IQ was assessed for coronary arteries using a 4-point scale (1=unevaluable to 4=excellent). Contrast-to-noise ratio (CNR) was measured in 9 locations. CT Dose Index and dose-length product were obtained, and the patients' effective dose was calculated. RESULTS Mean effective doses were 2.6 ± 1.4 mSv (range: 1.1 to 6.4) for the entire cardiac examination and 1.4 ± 0.7 mSv (0.4 to 3.1) for individual high-pitch cardiac CTA. z-coverage ranged from 9.9 cm in a native coronary CTA to 31.4 cm in a bypass graft case. The overall subjective IQ was good to excellent (mean score: 3.5), with 1.5% unevaluable coronary segments. The "double flash protocol" resulted in a fully diagnostic CT study in all cases just after taking both scans into consideration. The mean CNR of all locations was 19.7 ± 2.6. CONCLUSION Prospectively electrocardiograph-triggered high-pitch-mode cardiac CTA is a feasible and promising technique in clinical routine, allowing for evaluation of coronaries at good-to-excellent IQ and providing high CNR and minimal radiation doses. The "double flash protocol" might become a more robust tool in patients with elevated heart rates or premature ventricular contractions.
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Pauwels R, Theodorakou C, Walker A, Bosmans H, Jacobs R, Horner K, Bogaerts R. Dose distribution for dental cone beam CT and its implication for defining a dose index. Dentomaxillofac Radiol 2012; 41:583-93. [PMID: 22752320 DOI: 10.1259/dmfr/20920453] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES To characterize the dose distribution for a range of cone beam CT (CBCT) units, investigating different field of view sizes, central and off-axis geometries, full or partial rotations of the X-ray tube and different clinically applied beam qualities. The implications of the dose distributions on the definition and practicality of a CBCT dose index were assessed. METHODS Dose measurements on CBCT devices were performed by scanning cylindrical head-size water and polymethyl methacrylate phantoms, using thermoluminescent dosemeters, a small-volume ion chamber and radiochromic films. RESULTS It was found that the dose distribution can be asymmetrical for dental CBCT exposures throughout a homogeneous phantom, owing to an asymmetrical positioning of the isocentre and/or partial rotation of the X-ray source. Furthermore, the scatter tail along the z-axis was found to have a distinct shape, generally resulting in a strong drop (90%) in absorbed dose outside the primary beam. CONCLUSIONS There is no optimal dose index available owing to the complicated exposure geometry of CBCT and the practical aspects of quality control measurements. Practical validation of different possible dose indices is needed, as well as the definition of conversion factors to patient dose.
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Affiliation(s)
- R Pauwels
- Department of Oral Health Sciences, Leuven, Belgium.
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Kong CY, Lee JM, McMahon PM, Lowry KP, Omer ZB, Eisenberg JD, Pandharipande PV, Gazelle GS. Using radiation risk models in cancer screening simulations: important assumptions and effects on outcome projections. Radiology 2012; 262:977-84. [PMID: 22357897 DOI: 10.1148/radiol.11110352] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate the effect of incorporating radiation risk into microsimulation (first-order Monte Carlo) models for breast and lung cancer screening to illustrate effects of including radiation risk on patient outcome projections. MATERIALS AND METHODS All data used in this study were derived from publicly available or deidentified human subject data. Institutional review board approval was not required. The challenges of incorporating radiation risk into simulation models are illustrated with two cancer screening models (Breast Cancer Model and Lung Cancer Policy Model) adapted to include radiation exposure effects from mammography and chest computed tomography (CT), respectively. The primary outcome projected by the breast model was life expectancy (LE) for BRCA1 mutation carriers. Digital mammographic screening beginning at ages 25, 30, 35, and 40 years was evaluated in the context of screenings with false-positive results and radiation exposure effects. The primary outcome of the lung model was lung cancer-specific mortality reduction due to annual screening, comparing two diagnostic CT protocols for lung nodule evaluation. The Metropolis-Hastings algorithm was used to estimate the mean values of the results with 95% uncertainty intervals (UIs). RESULTS Without radiation exposure effects, the breast model indicated that annual digital mammography starting at age 25 years maximized LE (72.03 years; 95% UI: 72.01 years, 72.05 years) and had the highest number of screenings with false-positive results (2.0 per woman). When radiation effects were included, annual digital mammography beginning at age 30 years maximized LE (71.90 years; 95% UI: 71.87 years, 71.94 years) with a lower number of screenings with false-positive results (1.4 per woman). For annual chest CT screening of 50-year-old females with no follow-up for nodules smaller than 4 mm in diameter, the lung model predicted lung cancer-specific mortality reduction of 21.50% (95% UI: 20.90%, 22.10%) without radiation risk and 17.75% (95% UI: 16.97%, 18.41%) with radiation risk. CONCLUSION Because including radiation exposure risk can influence long-term projections from simulation models, it is important to include these risks when conducting modeling-based assessments of diagnostic imaging.
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Affiliation(s)
- Chung Y Kong
- Institute for Technology Assessment, Massachusetts General Hospital, 101 Merrimac St, 10th Floor, Boston, MA 02114, USA.
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Matsubara K, Sugai M, Toyoda A, Koshida H, Sakuta K, Takata T, Koshida K, Iida H, Matsui O. Assessment of an organ-based tube current modulation in thoracic computed tomography. J Appl Clin Med Phys 2012; 13:3731. [PMID: 22402390 PMCID: PMC5716412 DOI: 10.1120/jacmp.v13i2.3731] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 12/25/2011] [Accepted: 12/14/2011] [Indexed: 11/23/2022] Open
Abstract
Recently, specific computed tomography (CT) scanners have been equipped with organ-based tube current modulation (TCM) technology. It is possible that organ-based TCM will replace the conventional dose-reduction technique of reducing the effective milliampere-second. The aim of this study was to determine if organ-based TCM could reduce radiation exposure to the breasts without compromising the image uniformity and beam hardening effect in thoracic CT examinations. Breast and skin radiation doses and the absorbed radiation dose distribution within a single section were measured with an anthropomorphic phantom and radiophotoluminescent glass dosimeters using four approaches to thoracic CT (reference, organ-based TCM, copper shielding, and the combination of the above two techniques, hereafter referred to as the combination technique). The CT value and noise level were measured using the same calibration phantom. Organ-based TCM and copper shielding reduced radiation doses to the breast by 23.7% and 21.8%, respectively. However, the CT value increased, especially in the anterior region, using copper shielding. In contrast, the CT value and noise level barely increased using organ-based TCM. The combination technique reduced the radiation dose to the breast by 38.2%, but greatly increased the absorbed radiation dose from the central to the posterior regions. Moreover, the CT value increased in the anterior region and the noise level increased by more than 10% in the entire region. Therefore, organ-based TCM can reduce radiation doses to breasts with only small increases in noise levels, making it preferable for specific groups of patients, such as children and young women.
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Affiliation(s)
- Kosuke Matsubara
- Department of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan.
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He W, Marzolf SA, Tipnis S, Huda W. Scan region and organ doses in computed tomography. RADIATION PROTECTION DOSIMETRY 2012; 148:444-451. [PMID: 21561946 DOI: 10.1093/rpd/ncr200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The purpose of this study was to investigate how the choice of the scanned region affects organ doses in CT. ImPACT CT Patient Dosimetry Calculator (version 1.0) was used to compute absorbed doses to eight organs of interest in medical radiation dosimetry. For 13 dosimetry data sets, the authors calculated the maximum organ dose (D(max)) as well as the corresponding organ dose for a scan with selected length D(L). These data permitted the relative dose (D(r) = D(L)/D(max)) to be determined for varying scan lengths. Computations were performed for a nominal X-ray tube current of 100 mA, a rotation time of 1 s and a CT pitch of 1. The authors also determined values of D(max)/CTDI(vol), where CTDI(vol) is obtained in a 32-cm diameter CT dosimetry phantom using the same radiographic techniques. For each organ, D(r) was independent of the type of scanner, and increased monotonically to unity with increasing scan length. Relative doses for a scan restricted to the organ length ranged from 0.65 D(max) for the bladder to 0.86 D(max) for the lungs. There was good correlation (r = 0.64) between relative organ dose and the corresponding organ length. At 120 kV, the lowest value of D(max)/CTDI(vol) was 1.23 for the breast and the highest was 2.22 for the thyroid. Varying the X-ray tube voltage between 100 and 130 kV results in changes in D(max)/CTDI(vol) of no more than 4 %. CT scans limited to the direct irradiation of an average-sized organ results in an absorbed dose of ~0.75 D(max).
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Affiliation(s)
- Wenjun He
- Clemson-MUSC Bioengineering Program, Department of Bioengineering, Clemson University, 173 Ashley Avenue, PO Box 250508, Charleston, SC 29425, USA.
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Phan N, De Lisio M, Parise G, Boreham DR. Biological effects and adaptive response from single and repeated computed tomography scans in reticulocytes and bone marrow of C57BL/6 mice. Radiat Res 2011; 177:164-75. [PMID: 22059980 DOI: 10.1667/rr2532.1] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This study investigated the biological effects and adaptive responses induced by single and repeated in vivo computed tomography (CT) scans. We postulated that, through the induction of low-level oxidative stress, repeated low-dose CT scans (20 mGy, 2 days/week, 10 weeks) could protect mice (C57BL/6) from acute effects of high-dose radiation (1 Gy, 2 Gy). The micronucleated reticulocyte (MN-RET) count increased linearly after exposure to single CT scans of doses ranging from 20 to 80 mGy (P = 0.033). Ten weeks of repeated CT scans (total dose 400 mGy) produced a slight reduction in spontaneous MN-RET levels relative to levels in sham CT-scanned mice (P = 0.04). Decreases of nearly 10% in γ-H2AX fluorescence levels were observed in the repeated CT-scanned mice after an in vitro challenge dose of 1 Gy (P = 0.017) and 2 Gy (P = 0.026). Spontaneous apoptosis levels (caspase 3 and 7 activation) were also significantly lower in the repeated CT-scanned mice than the sham CT-scanned mice (P < 0.01). In contrast, mice receiving only a single CT scan showed a 19% elevation in apoptosis (P < 0.02) and a 10% increase in γ-H2AX fluorescence levels after a 2-Gy challenge (P < 0.05) relative to sham CT controls. Overall, repeated CT scans seemed to confer resistance to larger doses in mice, whereas mice exposed to single CT scans exhibited transient genotoxicity, enhanced apoptosis, and characteristics of radiation sensitization.
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Affiliation(s)
- Nghi Phan
- Department of Medical Physics and Applied Radiation Sciences, Nuclear Research Building Room 227, 1280 Main St. West, McMaster University, Hamilton, Ontario, Canada, L8S 4K1.
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Prins RD, Thornton RH, Schmidtlein CR, Quinn B, Ching H, Dauer LT. Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight. BMC Med Imaging 2011; 11:20. [PMID: 22004072 PMCID: PMC3224357 DOI: 10.1186/1471-2342-11-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 10/17/2011] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose. METHODS One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population. RESULTS Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters. CONCLUSIONS A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques.
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Affiliation(s)
- Robert D Prins
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th Street, New York, NY 10032, USA
| | - Raymond H Thornton
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - C Ross Schmidtlein
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - Brian Quinn
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - Hung Ching
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
| | - Lawrence T Dauer
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave. New York, NY 10021, USA
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Fujii K, Akahane K, Miyazaki O, Horiuchi T, Shimada A, Nagmatsu H, Yamauchi M, Yamauchi-Kawaura C, Kawasaki T. Evaluation of organ doses in CT examinations with an infant anthropomorphic phantom. RADIATION PROTECTION DOSIMETRY 2011; 147:151-155. [PMID: 21743079 DOI: 10.1093/rpd/ncr289] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of this study is to evaluate organ doses in infant CT examinations with multi-detector row CT scanners. Radiation doses were measured with radiophotoluminescence glass dosemeters set in various organ positions within a 1-y-old child anthropomorphic phantom and organ doses were evaluated from the measurement values. Doses for tissues or organs within the scan range were 28-36 mGy in an infant head CT, 3-11 mGy in a chest CT, 5-11 mGy in an abdominal-pelvic CT and 2-14 mGy in a cardiac CT. The doses varied by the differences in the types of CT scanners and scan parameters used at each medical facility. Compared with those for children of various ages, the doses in an infant CT protocol were found to be similar to or slightly smaller than those in a paediatric CT for 5- or 6-y-old children.
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Affiliation(s)
- K Fujii
- Department of Radiation, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba, Japan.
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Lee J, Kwon DG, Park SJ, Pai KS. Discordant findings on dimercaptosuccinic acid scintigraphy in children with multi-detector row computed tomography-proven acute pyelonephritis. KOREAN JOURNAL OF PEDIATRICS 2011; 54:212-8. [PMID: 21829413 PMCID: PMC3145906 DOI: 10.3345/kjp.2011.54.5.212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 11/10/2010] [Accepted: 12/22/2010] [Indexed: 11/27/2022]
Abstract
PURPOSE The diagnosis of acute pyelonephritis (APN) is often difficult, as its clinical and biological manifestations are non-specific in children. If not treated quickly and adequately, however, APN may cause irreversible renal damage, possibly leading to hypertension and chronic renal failure. We were suspecting the diagnostic value of (99m)Tc-dimercaptosuccinic acid (DMSA) scan by experiences and so compared the results of DMSA scan to those of multi-detector row computed tomography (MDCT). METHODS We retrospectively selected and analyzed 81 patients who were diagnosed as APN by MDCT during evaluation of their acute abdomen in emergency room and then received DMSA scan also for the diagnostic work-up of APN after admission. We evaluated the results of imaging studies and compared the diagnostic value of each method by age groups, <2 years (n=45) and ≥2 years (n=36). RESULTS Among total 81 patients with MDCT-proven APN. DMSA scan was diagnostic only in 55 children (68%), while the remaining 26 children (32%) showed false negative normal findings. These 26 patients were predominantly male with average age of 21 months and most of them, 19 (73.1%) were <2 years of age. CONCLUSION DMSA scan has obvious limitation compared to MDCT in depicting acute inflammatory lesions of kidney in children with APN, especially in early childhood less than 2 years of age. MDCT showed hidden lesions of APN, those were undetectable through DMSA scan in children.
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Affiliation(s)
- Jeongmin Lee
- Department of Pediatrics, Ajou University School of Medicine, Suwon, Korea
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Ban N, Takahashi F, Ono K, Hasegawa T, Yoshitake T, Katsunuma Y, Sato K, Endo A, Kai M. WAZA-ARI: computational dosimetry system for X-ray CT examinations II: development of web-based system. RADIATION PROTECTION DOSIMETRY 2011; 146:244-247. [PMID: 21502296 DOI: 10.1093/rpd/ncr161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A web-based dose computation system, WAZA-ARI, is being developed for patients undergoing X-ray CT examinations. The system is implemented in Java on a Linux server running Apache Tomcat. Users choose scanning options and input parameters via a web browser over the Internet. Dose coefficients, which were calculated in a Japanese adult male phantom (JM phantom) are called upon user request and are summed over the scan range specified by the user to estimate a normalised dose. Tissue doses are finally computed based on the radiographic exposure (mA s) and the pitch factor. While dose coefficients are currently available only for limited CT scanner models, the system has achieved a high degree of flexibility and scalability without the use of commercial software.
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Affiliation(s)
- Nobuhiko Ban
- Oita University of Nursing and Health Sciences, 2944-9 Megusuno, Oita-shi, Oita 870-1201, Japan.
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