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Gruszka W, Pietruschka SA. Two cases of vertebral perfusion disturbances in computer tomography imitating metastatic lesions in the course of superior vena cava thrombosis. Radiol Case Rep 2024; 19:2849-2855. [PMID: 38689807 PMCID: PMC11059305 DOI: 10.1016/j.radcr.2024.03.083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/25/2024] [Accepted: 03/28/2024] [Indexed: 05/02/2024] Open
Abstract
Skeletal metastases are frequently observed in various malignancies. In some cases, they are asymptomatic and can be found incidentally in various imaging methods in patients without known malignant tumors. In this case study 2 cases of vertebral perfusion disturbances are presented that imitate vertebral metastatic lesions in computer tomography in the course of superior vena cava thrombosis. The first patient was referred to our clinic for chest and abdominal computer tomography (CT) for staging due to a known tumor in the anterior mediastinum. The second patient was referred for chest CT due to swelling in the upper extremity and neck, with the suspected diagnosis of a tumor or pulmonary embolism. In both cases, CT scans showed metastases suspected lesions in the upper thoracic vertebral bodies. In both cases, additionally, the thrombosis of superior vena cava (SVC) and vena brachiocephalica was confirmed (in the first case due to tumor compression in the upper mediastinum, in the second case due to the presence of pacemaker leads). In control CT scans after anticoagulation treatment, there were no suspected lesions in the vertebral bodies, which confirmed the diagnosis of vertebral perfusion disturbances in the course of SVC thrombosis in both patients. In conclusion, in rare cases of metastases suspected lesions of thoracic vertebral bodies in contrast-enhanced computer tomography among patients with a diagnosis of superior vena cava thrombosis vertebral perfusion disturbances should be included in differential diagnosis protocol.
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Affiliation(s)
- Wojciech Gruszka
- Department of Radiology and Neuroradiology, Diakonie Klinikum Dietrich Bonhoeffer, S.-Allende-Str. 30, 17036 Neubrandenburg, Germany
| | - Sascha A. Pietruschka
- Department of Radiology and Neuroradiology, Diakonie Klinikum Dietrich Bonhoeffer, S.-Allende-Str. 30, 17036 Neubrandenburg, Germany
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Khoramian D, Haghparast M, Honardari A, Nouri E, Ranjbar E, Abedi‐Friouzjah R, Zarifi S, Anam C, Najafzadeh M, Afkhami‐Ardakni M. Estimation and comparison of the effective dose and lifetime attributable risk of thyroid cancer between males and females in routine head computed tomography scans: a multicentre study. J Med Radiat Sci 2024; 71:240-250. [PMID: 38216155 PMCID: PMC11177018 DOI: 10.1002/jmrs.752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 12/23/2023] [Indexed: 01/14/2024] Open
Abstract
INTRODUCTION A significant number of head computed tomography (CT) scans are performed annually. However, due to the close proximity of the thyroid gland to the radiation field, this procedure can expose the gland to ionising radiation. Consequently, this study aimed to estimate organ dose, effective dose (ED) and lifetime attributable risk (LAR) of thyroid cancer from head CT scans in adults. METHODS Head CT scans of 74 patients (38 males and 36 females) were collected using three different CT scanners. Age, sex, and scanning parameters, including scan length, tube current-time product (mAs), pitch, CT dose index, and dose-length product (DLP) were collected. CT-Expo software was used to calculate thyroid dose and ED for each patient based on scan parameters. LARs were subsequently computed using the methodology presented in the Biologic Effects of Ionizing Radiation (BEIR) Phase VII report. RESULTS Although the mean thyroid organ dose (2.66 ± 1.03 mGy) and ED (1.6 ± 0.4 mSv) were slightly higher in females, these differences were not statistically significant compared to males (mean thyroid dose, 2.52 ± 1.31 mGy; mean ED, 1.5 ± 0.4 mSv). Conversely, there was a significant difference between the mean thyroid LAR of females (0.91 ± 1.35) and males (0.20136 ± 0.29) (P = 0.001). However, the influencing parameters were virtually identical for both groups. CONCLUSIONS The study's results indicate that females have a higher LAR than males, which can be attributed to higher radiation sensitivity of the thyroid in females. Thus, additional care in the choice of scan parameters and irradiated scan field for female patients is recommended.
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Affiliation(s)
- Daryoush Khoramian
- The Advocate Centre for Clinical ResearchAyatollah Yasrebi HospitalKashanIran
| | - Mohammad Haghparast
- Department of Medical Physics, School of MedicineIran University of Medical SciencesTehranIran
- Department of Radiology, Faculty of Para‐MedicineHormozgan University of Medical SciencesBandar‐AbbasIran
| | - Adnan Honardari
- Department of Radiology, Faculty of Para‐MedicineHormozgan University of Medical SciencesBandar‐AbbasIran
| | - Ebrahim Nouri
- Department of Radiology, Faculty of Para‐MedicineHormozgan University of Medical SciencesBandar‐AbbasIran
| | - Esmail Ranjbar
- Department of Anatomy and Cell Biology, School of MedicineMashhad University of Medical SciencesMashhadIran
| | | | - Shiva Zarifi
- Radiation Oncology Department, Imam Reza Hospital, Faculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Choirul Anam
- Department of Physics, Faculty of Mathematics and SciencesDiponegoro UniversitySemarangIndonesia
| | - Milad Najafzadeh
- Department and Research Centre of Medical PhysicsMashhad University of Medical ScienceMashhadIran
| | - Mahdieh Afkhami‐Ardakni
- Department of Radiology, Faculty of Para‐MedicineHormozgan University of Medical SciencesBandar‐AbbasIran
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Rep S, Jensterle L, Zdešar U, Zaletel K, Tomše P, Ležaič L. Contribution of CT scan to patient's radiation exposure in parathyroid SPECT/CT scintigraphy. Radiography (Lond) 2024; 30:995-1000. [PMID: 38688163 DOI: 10.1016/j.radi.2024.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 05/02/2024]
Abstract
INTRODUCTION Dual phase technetium-99mTc-methoxy isobutyl isonitrile (MIBI) single-photon emission computed tomography with computed tomography (SPECT/CT) may be the most accurate conventional imaging approach for localization of enlarged parathyroid gland (EPG). The imaging is based on the radiopharmaceutical (RP) retention in EPG compared to washout from normal thyroid and normal parathyroid glands. This study aimed to estimate and optimize the contribution of computed tomography (CT) scan and scan range to effective dose (ED) in dual-phase MIBI SPECT/CT parathyroid scintigraphy. METHODS The study included seventy-four patients; thirty-seven with reduced and thirty-seven with extended CT scan range. The ED caused by the CT scan was calculated using Dose Length Product (DLP) data and estimated using the Imaging Performance Assessment of CT scanners (ImPACT) calculator. RESULTS For all patients, the contribution of CT to the ED in a combined SPECT/CT examination was 2.62 ± 0.29 mSv (48%). The contribution of CT to the total ED was 1.8 ± 0.18 mSv (33%) when using reduced and 3.44 ± 0.23 mSv (64%) when using extended scan range. The DLP and ED were statistically significantly different between the reduced and extended CT scan range (p < 0.001) in the first and second phases. The individual organ dose was reduced from 8% to 94%. CONCLUSION The hybrid SPECT/CT improves the interpretation of nuclear medicine images and also increases the radiation dose to the patient. An adequately defined CT scan range on SPECT/CT imaging, can significantly reduce a patient's ED. IMPLICATIONS FOR PRACTICE The research findings showed that knowledge of anatomy, pathology and technology can provide optimising diagnostic procedures and reduce patient ED after SPECT/CT scans.
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Affiliation(s)
- S Rep
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia; University of Ljubljana, Faculty of Health Sciences, Slovenia.
| | - L Jensterle
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - U Zdešar
- Institute of Occupational Safety, Ljubljana, Slovenia
| | - K Zaletel
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - P Tomše
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia
| | - L Ležaič
- Department of Nuclear Medicine, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Ahmad N, Dahlberg H, Jönsson H, Tarai S, Guggilla RK, Strand R, Lundström E, Bergström G, Ahlström H, Kullberg J. Voxel-wise body composition analysis using image registration of a three-slice CT imaging protocol: methodology and proof-of-concept studies. Biomed Eng Online 2024; 23:42. [PMID: 38614974 PMCID: PMC11015680 DOI: 10.1186/s12938-024-01235-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 04/02/2024] [Indexed: 04/15/2024] Open
Abstract
BACKGROUND Computed tomography (CT) is an imaging modality commonly used for studies of internal body structures and very useful for detailed studies of body composition. The aim of this study was to develop and evaluate a fully automatic image registration framework for inter-subject CT slice registration. The aim was also to use the results, in a set of proof-of-concept studies, for voxel-wise statistical body composition analysis (Imiomics) of correlations between imaging and non-imaging data. METHODS The current study utilized three single-slice CT images of the liver, abdomen, and thigh from two large cohort studies, SCAPIS and IGT. The image registration method developed and evaluated used both CT images together with image-derived tissue and organ segmentation masks. To evaluate the performance of the registration method, a set of baseline 3-single-slice CT images (from 2780 subjects including 8285 slices) from the SCAPIS and IGT cohorts were registered. Vector magnitude and intensity magnitude error indicating inverse consistency were used for evaluation. Image registration results were further used for voxel-wise analysis of associations between the CT images (as represented by tissue volume from Hounsfield unit and Jacobian determinant) and various explicit measurements of various tissues, fat depots, and organs collected in both cohort studies. RESULTS Our findings demonstrated that the key organs and anatomical structures were registered appropriately. The evaluation parameters of inverse consistency, such as vector magnitude and intensity magnitude error, were on average less than 3 mm and 50 Hounsfield units. The registration followed by Imiomics analysis enabled the examination of associations between various explicit measurements (liver, spleen, abdominal muscle, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), thigh SAT, intermuscular adipose tissue (IMAT), and thigh muscle) and the voxel-wise image information. CONCLUSION The developed and evaluated framework allows accurate image registrations of the collected three single-slice CT images and enables detailed voxel-wise studies of associations between body composition and associated diseases and risk factors.
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Affiliation(s)
- Nouman Ahmad
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden.
| | - Hugo Dahlberg
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Hanna Jönsson
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Sambit Tarai
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | | | - Robin Strand
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Department of Information Technology, Uppsala University, Uppsala, Sweden
| | - Elin Lundström
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Göran Bergström
- Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Clinical Physiology, Sahlgrenska University Hospital, Region Västra Götaland, Gothenburg, Sweden
| | - Håkan Ahlström
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical, Mölndal, Sweden
| | - Joel Kullberg
- Radiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Antaros Medical, Mölndal, Sweden
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Manfield J, Thomas S, Bogdanovic M, Sarangmat N, Antoniades C, Green AL, FitzGerald JJ. Seeing Is Believing: Photon Counting Computed Tomography Clearly Images Directional Deep Brain Stimulation Lead Segments and Markers After Implantation. Neuromodulation 2024; 27:557-564. [PMID: 37921733 DOI: 10.1016/j.neurom.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/11/2023] [Accepted: 09/12/2023] [Indexed: 11/04/2023]
Abstract
BACKGROUND AND OBJECTIVES Directional deep brain stimulation (DBS) electrodes are increasingly used, but conventional computed tomography (CT) is unable to directly image segmented contacts owing to physics-based resolution constraints. Postoperative electrode segment orientation assessment is necessary because of the possibility of significant deviation during or immediately after insertion. Photon-counting detector (PCD) CT is a relatively novel technology that enables high resolution imaging while addressing several limitations intrinsic to CT. We show how PCD CT can enable clear in vivo imaging of DBS electrodes, including segmented contacts and markers for all major lead manufacturers. MATERIALS AND METHODS We describe postoperative imaging and reconstruction protocols we have developed to enable optimal lead visualization. PCD CT images were obtained of directional leads from the three major manufacturers and fused with preoperative 3T magnetic resonance imaging (MRI). Radiation dosimetry also was evaluated and compared with conventional imaging controls. Orientation estimates from directly imaged leads were compared with validated software-based reconstructions (derived from standard CT imaging artifact analysis) to quantify congruence in alignment and directional orientation. RESULTS High-fidelity images were obtained for 15 patients, clearly indicating the segmented contacts and directional markers both on CT alone and when fused to MRI. Our routine imaging protocol is described. Ionizing radiation doses were significantly lower than with conventional CT. For most leads, the directly imaged lead orientations and depths corresponded closely to those predicted by CT artifact-based reconstructions. However, unlike direct imaging, the software reconstructions were susceptible to 180° error in orientation assessment. CONCLUSIONS High-resolution photon-counting CT can very clearly image segmented DBS electrode contacts and directional markers and unambiguously determine lead orientation, with lower radiation than in conventional imaging. This obviates the need for further imaging and may facilitate anatomically tailored directional programming.
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Affiliation(s)
- James Manfield
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | - Sheena Thomas
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Marko Bogdanovic
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK
| | | | | | - Alexander L Green
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - James J FitzGerald
- Oxford Functional Neurosurgery, John Radcliffe Hospital, Oxford, UK; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK.
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Prabsattroo T, Wachirasirikul K, Tansangworn P, Punikhom P, Sudchai W. The Dose Optimization and Evaluation of Image Quality in the Adult Brain Protocols of Multi-Slice Computed Tomography: A Phantom Study. J Imaging 2023; 9:264. [PMID: 38132682 PMCID: PMC10743697 DOI: 10.3390/jimaging9120264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/23/2023] Open
Abstract
Computed tomography examinations have caused high radiation doses for patients, especially for CT scans of the brain. This study aimed to optimize the radiation dose and image quality in adult brain CT protocols. Images were acquired using a Catphan 700 phantom. Radiation doses were recorded as CTDIvol and dose length product (DLP). CT brain protocols were optimized by varying parameters such as kVp, mAs, signal-to-noise ratio (SNR) level, and Clearview iterative reconstruction (IR). The image quality was also evaluated using AutoQA Plus v.1.8.7.0 software. CT number accuracy and linearity had a robust positive correlation with the linear attenuation coefficient (µ) and showed more inaccurate CT numbers when using 80 kVp. The modulation transfer function (MTF) showed a higher value in 100 and 120 kVp protocols (p < 0.001), while high-contrast spatial resolution showed a higher value in 80 and 100 kVp protocols (p < 0.001). Low-contrast detectability and the contrast-to-noise ratio (CNR) tended to increase when using high mAs, SNR, and the Clearview IR protocol. Noise decreased when using a high radiation dose and a high percentage of Clearview IR. CTDIvol and DLP were increased with increasing kVp, mAs, and SNR levels, while the increasing percentage of Clearview did not affect the radiation dose. Optimized protocols, including radiation dose and image quality, should be evaluated to preserve diagnostic capability. The recommended parameter settings include kVp set between 100 and 120 kVp, mAs ranging from 200 to 300 mAs, SNR level within the range of 0.7-1.0, and an iterative reconstruction value of 30% Clearview to 60% or higher.
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Affiliation(s)
- Thawatchai Prabsattroo
- Department of Radiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (K.W.); (P.T.); (P.P.)
| | - Kanokpat Wachirasirikul
- Department of Radiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (K.W.); (P.T.); (P.P.)
| | - Prasit Tansangworn
- Department of Radiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (K.W.); (P.T.); (P.P.)
| | - Puengjai Punikhom
- Department of Radiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (K.W.); (P.T.); (P.P.)
| | - Waraporn Sudchai
- Nuclear Technology Service Center, Thailand Institute of Nuclear Technology, Nakhon Nayok 26120, Thailand;
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Al Mohammad B, Alakhras MM, Reed W. Assessing the knowledge of CT radiographers regarding how CT parameters affect patient dose and image quality. Eur J Radiol 2023; 166:111023. [PMID: 37542813 DOI: 10.1016/j.ejrad.2023.111023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/14/2023] [Accepted: 07/31/2023] [Indexed: 08/07/2023]
Abstract
PURPOSE The objective of this study was to assess the current knowledge of CT radiographers regarding the optimization of CT parameters and their consequential effects on both patient dose and image quality. METHOD A nationwide, cross sectional study was conducted from the 2nd of January 2023 to 1st of March 2023 to evaluate CT radiographers' knowledge in managing CT parameters in Jordan. Recruitment involved convenience sampling where radiographers were invited to participate and complete the questionnaire. Descriptive statistics were used to report the normalized knowledge scores. Student's t-test and ANOVA were used to investigate and compare the outcomes between different subgroups. A forward stepwise linear regression was used to investigate the influence of a number of technologist related factors on the knowledge score. RESULTS Three hundred and fifty-seven radiographers participated in the study, with a mean knowledge score of 69.0%. Participants with an academic master's degree had a significantly higher score of 72.1% compared to the ones with a diploma degree, with a score of 66.8% (p = 0.026). No statistically significant difference was found between radiographers that received additional training and the ones that did not. Furthermore, when investigating the effects of academic education, working sector, additional training and years of experience, only education had a statistically significant impact on the knowledge score. CONCLUSION The results demonstrate that radiographers have an overall good understanding of CT parameters, with academic education having a significant influence on their performance.
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Affiliation(s)
- Badera Al Mohammad
- Department of Allied Medical Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan.
| | - Maram M Alakhras
- Department of Allied Medical Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Warren Reed
- Discipline of Medical Imaging Science, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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Lin B, Xu X, Shen Z, Huang P, Gao Y, Liu J, Xie Z, Zhao T, Xia J, Lv J, Ren D, Zheng H, Wang X, Hu M, Ruan G, Zhang M. Clinical and radiological characteristics of pediatric COVID-19 before and after the Omicron outbreak: a multi-center study. Front Pediatr 2023; 11:1172111. [PMID: 37664548 PMCID: PMC10470622 DOI: 10.3389/fped.2023.1172111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/31/2023] [Indexed: 09/05/2023] Open
Abstract
Introduction The emergence of the Omicron variant has seen changes in the clinical and radiological presentations of COVID-19 in pediatric patients. We sought to compare these features between patients infected in the early phase of the pandemic and those during the Omicron outbreak. Methods A retrospective study was conducted on 68 pediatric COVID-19 patients, of which 31 were infected with the original SARS-CoV-2 strain (original group) and 37 with the Omicron variant (Omicron group). Clinical symptoms and chest CT scans were examined to assess clinical characteristics, and the extent and severity of lung involvement. Results Pediatric COVID-19 patients predominantly had normal or mild chest CT findings. The Omicron group demonstrated a significantly reduced CT severity score than the original group. Ground-glass opacities were the prevalent radiological findings in both sets. The Omicron group presented with fewer symptoms, had milder clinical manifestations, and recovered faster than the original group. Discussion The clinical and radiological characteristics of pediatric COVID-19 patients have evolved with the advent of the Omicron variant. For children displaying severe symptoms warranting CT examinations, it is crucial to weigh the implications of ionizing radiation and employ customized scanning protocols and protective measures. This research offers insights into the shifting disease spectrum, aiding in the effective diagnosis and treatment of pediatric COVID-19 patients.
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Affiliation(s)
- Bin Lin
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaopei Xu
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhujing Shen
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Peiyu Huang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuantong Gao
- Department of Radiology, The Third Affiliated Hospital of Wenzhou Medical University, Ruian, China
| | - Jun Liu
- Department of Radiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Zongyu Xie
- Department of Radiology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China
| | - Tongtong Zhao
- Department of Radiology, The Second People's Hospital, Fuyang, China
| | - Junli Xia
- Department of Radiology, Bozhou Bone Trauma Hospital, Bozhou, China
| | - Jian Lv
- Department of Radiology, Nanxishan Hospital, Gui Lin, China
| | - Dawei Ren
- Department of Radiology, Ningbo First Hospital, Ningbo, China
| | - Hanpeng Zheng
- Department of Radiology, Yueqing People's Hospital, Wenzhou, China
| | - Xiangming Wang
- Department of Radiology, Yiwu Central Hospital, Yiwu, China
| | - Minghua Hu
- Department of Radiology, Taizhou Central Hospital, Taizhou University Hospital, Taizhou, China
| | - Guixiang Ruan
- Department of Radiology, The First People's Hospital of Yuhang District, Hangzhou, China
| | - Minming Zhang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Bohang SAM, Sohaimi N. An Overview on the Alignment of Radiation Protection in Computed Tomography with Maqasid al-Shari'ah in the Context of al-Dharuriyat. Malays J Med Sci 2023; 30:60-72. [PMID: 37425388 PMCID: PMC10325131 DOI: 10.21315/mjms2023.30.3.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 01/08/2022] [Indexed: 07/11/2023] Open
Abstract
The increasing utilisation of computed tomography (CT) in the medical field has raised a greater concern regarding the radiation-induced health effects as CT imposes high radiation risks on the exposed individual. Adherence to radiation protection measures in CT as endorsed by regulatory bodies; justification, optimisation and dose limit, is essential to minimise radiation risks. Islam values every human being and Maqasid al-Shari'ah helps to protect human beings through its sacred principles which aim to fulfil human beings' benefits (maslahah) and prevent mischief (mafsadah). Alignment of the concept of radiation protection in CT within the framework of al-Dharuriyat; protection of faith or religion (din), protection of life (nafs), protection of lineage (nasl), protection of intellect ('aql) and protection of property (mal) is essential. This strengthens the concept and practices of radiation protection in CT among radiology personnel, particularly Muslim radiographers. The alignment provides supplementary knowledge towards the integration of knowledge fields between Islamic worldview and radiation protection in medical imaging, particularly in CT. This paper is hoped to set a benchmark for future studies on the integration of knowledge between the Islamic worldview and radiation protection in medical imaging in terms of other classifications of Maqasid al-Shari'ah; al-Hajiyat and al-Tahsiniyat.
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Affiliation(s)
- Siti Aisyah Munirah Bohang
- Department of Diagnostic Imaging and Radiotherapy, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Pahang, Malaysia
| | - Norhanna Sohaimi
- Department of Diagnostic Imaging and Radiotherapy, Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Pahang, Malaysia
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Suliman II, Khouqeer GA, Ahmed NA, Abuzaid MM, Sulieman A. Low-Dose Chest CT Protocols for Imaging COVID-19 Pneumonia: Technique Parameters and Radiation Dose. Life (Basel) 2023; 13:life13040992. [PMID: 37109522 PMCID: PMC10146316 DOI: 10.3390/life13040992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/29/2023] [Accepted: 04/02/2023] [Indexed: 04/29/2023] Open
Abstract
Chest computed tomography (CT) plays a vital role in the early diagnosis, treatment, and follow-up of COVID-19 pneumonia during the pandemic. However, this raises concerns about excessive exposure to ionizing radiation. This study aimed to survey radiation doses in low-dose chest CT (LDCT) and ultra-low-dose chest CT (ULD) protocols used for imaging COVID-19 pneumonia relative to standard CT (STD) protocols so that the best possible practice and dose reduction techniques could be recommended. A total of 564 articles were identified by searching major scientific databases, including ISI Web of Science, Scopus, and PubMed. After evaluating the content and applying the inclusion criteria to technical factors and radiation dose metrics relevant to the LDCT protocols used for imaging COVID-19 patients, data from ten articles were extracted and analyzed. Technique factors that affect the application of LDCT and ULD are discussed, including tube current (mA), peak tube voltage (kVp), pitch factor, and iterative reconstruction (IR) algorithms. The CTDIvol values for the STD, LDCT, and ULD chest CT protocols ranged from 2.79-13.2 mGy, 0.90-4.40 mGy, and 0.20-0.28 mGy, respectively. The effective dose (ED) values for STD, LDCT, and ULD chest CT protocols ranged from 1.66-6.60 mSv, 0.50-0.80 mGy, and 0.39-0.64 mSv, respectively. Compared with the standard (STD), LDCT reduced the dose reduction by a factor of 2-4, whereas ULD reduced the dose reduction by a factor of 8-13. These dose reductions were achieved by applying scan parameters and techniques such as iterative reconstructions, ultra-long pitches, and fast spectral shaping with a tin filter. Using LDCT, the cumulative radiation dose of serial CT examinations during the acute period of COVID-19 may have been inferior or equivalent to that of conventional CT.
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Affiliation(s)
- Ibrahim I Suliman
- Department of Physics, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11642, Saudi Arabia
- Deanship of Scientific Research, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11642, Saudi Arabia
| | - Ghada A Khouqeer
- Department of Physics, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11642, Saudi Arabia
| | - Nada A Ahmed
- Faculty of Science, Taibah University, Al Madinah Al Munawwarah 42353, Saudi Arabia
| | - Mohamed M Abuzaid
- Medical Diagnostic Imaging Department, College of Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates
| | - Abdelmoneim Sulieman
- Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
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Bai J, Zhang W, Zhang W, Zhang B. APPLICATION OF CT PULMONARY ANGIOGRAPHY WITH "ULTRA-DOUBLE-LOW" AND ITERATIVE MODEL RECONSTRUCTION FOR ACUTE PULMONARY EMBOLISM. RADIATION PROTECTION DOSIMETRY 2023; 199:ncac279-215. [PMID: 36578222 DOI: 10.1093/rpd/ncac279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 11/27/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
The study is to investigate the feasibility of computed tomography pulmonary angiography (CTPA) with iterative model reconstruction (IMR) and "Ultra-double-low" (Ultra-low dose, Ultra-low contrast agent volume). Thirty-six patients who tested positive for pulmonary embolism in CTPA were enrolled in the study. Another CTPA was performed 1 week after thrombolytic therapy. The first examination was routine CTPA (Routine Group) with the parameters as follows: automatic mA scanning, 120 kV and image reconstruction by using iDose4 iterative reconstruction (Lever 4), iodine concentration and dose of contrast agent: 300 mgI/ml and 0.5 gI/kg, respectively. The latter one was ultra-low dose CTPA examination (Ultra-low Group): 40 mAs, 80 kV and IMR (Lever 3), contrast agent: 300 mgI/ml and 15 mL, respectively. Effective dose (ED), CT dose index volume (CTDIvol), dose length product (DLP), attenuation of pulmonary artery, contrast noise ratio (CNR) and signal noise ratio (SNR) were recorded and calculated. The imaging qualities were subjectively assessed. The Eds/CTDIvols/DLPs of Ultra-low Group are lower than the Routine Group (P < 0.05). The differences in attenuation between the two groups are not significant (P > 0.05). The differences in CNR and SNR between the two groups are significant (P < 0.05). The differences in imaging qualities between the two groups when subjectively assessed are not significant (P > 0.05). The 256-slice spiral CT combined with IMR and "Ultra-double-low" is feasible for the acute pulmonary embolism examination and the radiation dose and the volume of contrast agent can be greatly reduced.
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Affiliation(s)
- Jiayuan Bai
- Department of Radiology, Second Affiliated Hospital of Soochow University, No. 1055, Sanxiang Road, Suzhou 215004, P.R. China
| | - Wanjun Zhang
- Department of Radiology, Second Affiliated Hospital of Soochow University, No. 1055, Sanxiang Road, Suzhou 215004, P.R. China
| | - Wei Zhang
- Department of Radiology, Second Affiliated Hospital of Soochow University, No. 1055, Sanxiang Road, Suzhou 215004, P.R. China
| | - Bo Zhang
- Department of Radiology, Second Affiliated Hospital of Soochow University, No. 1055, Sanxiang Road, Suzhou 215004, P.R. China
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Preston S, Liu J, Eisenbeis L, Cohen A, Fishman EK, Coon D. 3D CT Urethrography With Cinematic Rendering (3DUG): A New Modality for Evaluation of Complex Urethral Anatomy and Assessment of the Postoperative Phalloplasty Urethra. Urology 2023; 174:212-217. [PMID: 36708932 DOI: 10.1016/j.urology.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 01/01/2023] [Accepted: 01/08/2023] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To develop an imaging modality for the postoperative phalloplasty urethra. Despite high urologic complication rates after masculinizing genital surgery, existing methods for postsurgical evaluation after phalloplasty have drawbacks. Fluoroscopic studies like the retrograde urethrogram have limitations like user-dependence and need for meticulous positioning but also are inadequate for the evaluation of the anatomically complex postphalloplasty urethra. We developed a novel protocol utilizing CT urethrography with 3D reconstruction using cinematic rendering (3DUG) for neo-urethral imaging. MATERIALS AND METHODS Patients who underwent 3DUG after either phalloplasty, metoidioplasty, or prior to revision surgery were included. Low-dose imaging protocols were used to avoid any increases in radiation exposure. The first iteration of our protocol utilized retrograde contrast administration via the penile urethra, whereas the second iteration of our protocol utilized an antegrade technique with contrast instillation via the suprapubic catheter and a voiding scan. Imaging was initially obtained according to symptoms and then per protocol at 3 weeks after urethral lengthening. RESULTS Twenty-six patients were included in the series. Among postoperative phalloplasty patients imaged for symptoms, contrast extravasation/fistula was identified in 5 (63%), vaginal remnant in 3 (38%), and stricture in 2 (25%) compared to 5 (45%), 1 (9%), and zero respectively for patients imaged routinely. When intervention was required, operative findings correlated to anatomy on imaging. CONCLUSION We present a new protocol for the use of 3D CT urethrography with cinematic rendering for neo-urethral reconstruction. This technique has the potential to improve surgical planning and surveillance of urologic complications in postphalloplasty patients.
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Affiliation(s)
- Stephanie Preston
- Department of Plastic and Reconstructive Surgery, Beth Israel Deaconess Medical Center, Boston, MA
| | - James Liu
- Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins University, Baltimore, MD
| | - Lauren Eisenbeis
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University, Baltimore, MD
| | - Andrew Cohen
- Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins University, Baltimore, MD
| | - Elliot K Fishman
- Department of Radiology, Johns Hopkins University, Baltimore, MD
| | - Devin Coon
- Department of Plastic and Reconstructive Surgery, Johns Hopkins University, Baltimore, MD; Division of Plastic and Reconstructive Surgery, Brigham & Women's Hospital and Harvard Medical School, Boston, MA.
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13
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Optimization of smoothing factor for fast non-local means algorithm in high pitch based low-dose computed tomography images with tin-filter. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2023.110762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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14
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Patient dose estimation in CT examination using dose conversion coefficient method and CT -expo software. HEALTH AND TECHNOLOGY 2022. [DOI: 10.1007/s12553-022-00683-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Patient dose in CT angiography examinations: An institutional survey. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Luu MH, Walsum TV, Mai HS, Franklin D, Nguyen TTT, Le TM, Moelker A, Le VK, Vu DL, Le NH, Tran QL, Chu DT, Trung NL. Automatic scan range for dose-reduced multiphase CT imaging of the liver utilizing CNNs and Gaussian models. Med Image Anal 2022; 78:102422. [PMID: 35339951 DOI: 10.1016/j.media.2022.102422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 12/27/2021] [Accepted: 03/11/2022] [Indexed: 12/24/2022]
Abstract
Multiphase CT scanning of the liver is performed for several clinical applications; however, radiation exposure from CT scanning poses a nontrivial cancer risk to the patients. The radiation dose may be reduced by determining the scan range of the subsequent scans by the location of the target of interest in the first scan phase. The purpose of this study is to present and assess an automatic method for determining the scan range for multiphase CT scans. Our strategy is to first apply a CNN-based method for detecting the liver in 2D slices, and to use a liver range search algorithm for detecting the liver range in the scout volume. The target liver scan range for subsequent scans can be obtained by adding safety margins achieved from Gaussian liver motion models to the scan range determined from the scout. Experiments were performed on 657 multiphase CT volumes obtained from multiple hospitals. The experiment shows that the proposed liver detection method can detect the liver in 223 out of a total of 224 3D volumes on average within one second, with mean intersection of union, wall distance and centroid distance of 85.5%, 5.7 mm and 9.7 mm, respectively. In addition, the performance of the proposed liver detection method is comparable to the best of the state-of-the-art 3D liver detectors in the liver detection accuracy while it requires less processing time. Furthermore, we apply the liver scan range generation method on the liver CT images acquired from radiofrequency ablation and Y-90 transarterial radioembolization (selective internal radiation therapy) interventions of 46 patients from two hospitals. The result shows that the automatic scan range generation can significantly reduce the effective radiation dose by an average of 14.5% (2.56 mSv) compared to manual performance by the radiographer from Y-90 transarterial radioembolization, while no statistically significant difference in performance was found with the CT images from intra RFA intervention (p = 0.81). Finally, three radiologists assess both the original and the range-reduced images for evaluating the effect of the range reduction method on their clinical decisions. We conclude that the automatic liver scan range generation method is able to reduce excess radiation compared to the manual performance with a high accuracy and without penalizing the clinical decision.
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Affiliation(s)
- Manh Ha Luu
- AVITECH, University of Engineering and Technology, VNU, Hanoi, Vietnam; Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, the Netherlands; FET, University of Engineering and Technology, VNU, Hanoi, Vietnam.
| | - Theo van Walsum
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, the Netherlands
| | - Hong Son Mai
- Department of Nuclear Medicine, Hospital 108, Hanoi, Vietnam
| | - Daniel Franklin
- School of Electrical and Data Engineering, University of Technology Sydney, Sydney, Australia
| | | | - Thi My Le
- Department of Radiology and Nuclear Medicine, Vinmec Hospital, Hanoi, Vietnam
| | - Adriaan Moelker
- Department of Radiology and Nuclear Medicine, Erasmus MC, Rotterdam, the Netherlands
| | - Van Khang Le
- Radiology Center, Bach Mai Hospital, Hanoi, Vietnam
| | - Dang Luu Vu
- Radiology Center, Bach Mai Hospital, Hanoi, Vietnam
| | - Ngoc Ha Le
- Department of Nuclear Medicine, Hospital 108, Hanoi, Vietnam
| | - Quoc Long Tran
- FIT, University of Engineering and Technology, VNU, Hanoi, Vietnam
| | - Duc Trinh Chu
- FET, University of Engineering and Technology, VNU, Hanoi, Vietnam
| | - Nguyen Linh Trung
- AVITECH, University of Engineering and Technology, VNU, Hanoi, Vietnam
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Arslan S, Onur MR, Sarıkaya Y, Özcan HN, Haliloğlu M, Akata D. Radiation dose levels of thoracic-lumbar spine CT in pediatric trauma patients and assessment of scan parameters for dose optimization. Pediatr Radiol 2022; 52:65-74. [PMID: 34651195 DOI: 10.1007/s00247-021-05170-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/05/2021] [Accepted: 07/31/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND CT is frequently used for assessing spinal trauma in children. OBJECTIVE To establish the local diagnostic reference levels of spine CT examinations in pediatric spinal trauma patients and analyze scan parameters to enable dose optimization. MATERIALS AND METHODS In this retrospective study, we included 192 pediatric spinal trauma patients who underwent spine CT. Children were divided into two age groups: 0-10 years (group 1) and 11-17 years (group 2). Each group was subdivided into thoracic, thoracolumbar and lumbar CT groups. CT acquisition parameters (tube potential, in kilovoltage [kV]; mean tube current-time product, in milliamperes [mAs]; reference mAs; collimated slice width; tube rotation time; pitch; scan length) and radiation dose descriptors (volume CT dose index [CTDIvol] and dose-length product [DLP]) were recorded. The CTDIvol and DLP values of spine CTs obtained with different tube potential and collimated slice width values were compared for each group. RESULTS CTDIvol and DLP values of thoracolumbar spine CTs in group 1 and lumbar spine CTs in group 2 were significantly lower in CTs acquired with low tube potential levels (P<0.05). CTDIvol and DLP values of thoracolumbar spine CTs in both groups and lumbar spine CTs in group 2 acquired with high collimated slice width values were significantly lower than in corresponding CTs acquired with low collimated slice width values (P<0.05). CONCLUSION Pediatric spine CT radiation doses can be notably reduced from the manufacturers' default protocols while preserving image quality.
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Affiliation(s)
- Sevtap Arslan
- Department of Radiology, Hacettepe University School of Medicine, Adnan Saygun St., Ankara, 06230, Turkey.
| | - Mehmet Ruhi Onur
- Department of Radiology, Hacettepe University School of Medicine, Adnan Saygun St., Ankara, 06230, Turkey
| | - Yasin Sarıkaya
- Department of Radiology, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
| | - H Nursun Özcan
- Department of Radiology, Hacettepe University School of Medicine, Adnan Saygun St., Ankara, 06230, Turkey
| | - Mithat Haliloğlu
- Department of Radiology, Hacettepe University School of Medicine, Adnan Saygun St., Ankara, 06230, Turkey
| | - Deniz Akata
- Department of Radiology, Hacettepe University School of Medicine, Adnan Saygun St., Ankara, 06230, Turkey
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Khezerloo D, Iranmakani S, Jahanshahi A, Mehnati P, Mortezazadeh T. Image quality and pulmonary nodule detectability at low-dose computed tomography (low kVp and mAs): A phantom study. JOURNAL OF MEDICAL SIGNALS & SENSORS 2022; 12:64-68. [PMID: 35265467 PMCID: PMC8804592 DOI: 10.4103/jmss.jmss_65_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 06/04/2021] [Accepted: 08/27/2021] [Indexed: 11/08/2022]
Abstract
Background: Nowadays, there has been a growing demand for low-dose computed tomography (LDCT) protocols. CT has a critical role in the management of the diagnosis chain of pulmonary disease, especially in lung cancer screening. There have been introduced several dose reduction methods, however, most of them are time-consuming, intricate, and vendor-based strategies that are hardly used in clinics routinely. This study aims to evaluate the image quality and pulmonary nodule detectability of LDCT protocols that are feasible and easy implemented. Image quality was analyzed in a general quality control phantom (Gammex) and then in a manmade lung phantom with nodules-equivalent objects. Methods: This study was designed in a two steps, in the first step, a feasible low-dose lung CT protocol was selected with quality assessment of accreditation phantom image. In the second step, the selected low-dose protocol with an appropriate image quality was performed on a manmade lung phantom in which there were objects equivalent to the pulmonary nodule. Finally, image quality parameters of the phantom at the appropriate scan protocol were compared with the standard protocol. Results: A reduction of about 17% of kVp and 46% in tube current leads to dose reduction by about 70%. The contrast-to-noise ratio in the low-dose protocol remained almost unchanged. The signal-to-noise ratio in the low-dose protocol decreased by approximately 32%, and the noise level has increased by about 1.5 times. However, this reduction method hardly affected the detectability of nodules in man-made pulmonary phantom. Conclusions: Here, we demonstrated that the LDCT scan has an insignificant effect on the perception of lung nodules. In this study, patient dose in lung CT was reduced by modifying of kVp and mAs about approximately 70%. Hence, to step in toward low-dose strategies in medical imaging clinics, using easy-implemented and feasible low-dose strategies may be helpful.
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20
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Abedi I, Choopani M, Dalvand F. Pragmatic approaches to reducing radiation dose in brain computed tomography scan using scan parameter modification. JOURNAL OF MEDICAL SIGNALS & SENSORS 2022; 12:219-226. [PMID: 36120405 PMCID: PMC9480513 DOI: 10.4103/jmss.jmss_83_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 11/01/2021] [Indexed: 11/29/2022]
Abstract
Background: High radiation dose of patients has become a concern in the computed tomography (CT) examinations. The aim of this study is to guide the radiology technician in modifying or optimizing the underlying parameters of the CT scan to reduce the patient radiation dose and produce an acceptable image quality for diagnosis. Methods: The body mass measurement device phantom was repeatedly scanned by changing the scan parameters. To analyze the image quality, software-based and observer-based evaluations were employed. To study the effect of scan parameters such as slice thickness and reconstruction filter on image quality and radiation dose, the structural equation modeling was used. Results: By changing the reconstruction filter from standard to soft and slice thickness from 2.5 mm to 5 mm, low-contrast resolution did not change significantly. In addition, by increasing the slice thickness and changing the reconstruction filter, the spatial resolution at different radiation conditions did not significantly differ from the standard irradiation conditions (P > 0.05). Conclusion: In this study, it was shown that in the brain CT scan imaging, the radiation dose was reduced by 30%–50% by increasing the slice thickness or changing the reconstruction filter. It is necessary to adjust the CT scan protocols according to clinical requirements or the special conditions of some patients while maintaining acceptable image quality.
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21
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Awe OO, Obed RI, Adekanmi AJ, Ogbole GI, Agbele AT. Thyroid dose and cancer risk from head and neck computed tomography at two selected centres in Nigeria. Niger Postgrad Med J 2021; 28:278-284. [PMID: 34850756 DOI: 10.4103/npmj.npmj_611_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Objective The objective of this study was to evaluate the thyroid glands' radiation dose and the risk of thyroid cancer induction from head or neck computed tomography (CT) examinations. Methods In a prospective study, we evaluated all participants of all ages and sex referred for Head or Neck CT Scan at the University College Hospital, Ibadan and Me Cure Healthcare Limited, Ibadan, Oyo State, Nigeria. Thyroid radiation dose was estimated with impact scan calculator, and real-time dose measurement with thermoluminescent badge dosimeters (TLDs). Data were analysed and P < 0.05 was considered statistically significant. Results One hundred and sixty-three participants (128 adults and 35 children) participated in the study. In most participants (74%), the tube voltage was 120 kVp. The estimated median thyroid gland dose by the imPACT scan calculator was 4.95 mGy (range = 1.20-30.0 mGy) and 4.40 mGy (range = 3.0-5.10 mGy), while the real-time dose measured by the TLD was 4.79 mGy (range = 1.73-96.7 mGy) and 2.33 mGy (range = 1.20-3.73 mGy) at Centre A and B, respectively. The estimated median thyroid cancer risk was 2.88 × 10-6 (maximum range of 52 × 10-6) at centre A and a median value of 3.20 × 10-6 with a cancer risk estimate that may reach 17.9 × 10-6 recorded at centre B, compared to a cumulative thyroid cancer risk of 0.12 × 10-5 among the general Nigerian population. Conclusions Scanner specifications and technique may significantly contribute to variations seen in thyroid radiation doses. There may be a need to optimise centre protocols and apply dose reference levels for head and neck CT examinations to reduce thyroid cancer risk in Nigeria.
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Affiliation(s)
- Olufisayo Olalekan Awe
- Department of Basic Sciences, Physics Electronics Unit, Babcock University, Ilishan-Remo; Department of Physics, University of Ibadan, Ibadan, Oyo State, Nigeria
| | | | | | - Godwin I Ogbole
- Department of Radiology, University College Teaching Hospital, Ibadan, Oyo State, Nigeria
| | - Alaba Tolulope Agbele
- Department of Basic Medical Sciences, College of Health Sciences and Technology, Ijero-Ekiti, Nigeria
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22
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Dalah EZ, Obaideen A, Anam S, Khalid M, Nadishani T, Hashim S, Ghoshal SK. Cumulative lifetime attributed risks for patients subjected to contrast enhanced chest CT examinations. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Dimitroukas CP, Metaxas VI, Efthymiou FO, Zampakis PE, Kalogeropoulou CP, Panayiotakis GS. DOSIMETRIC EVALUATION OF THE TWO-PHASE COMPUTED TOMOGRAPHY IN PARATHYROID GLANDS IMAGING. RADIATION PROTECTION DOSIMETRY 2021; 196:207-219. [PMID: 34635914 DOI: 10.1093/rpd/ncab137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/03/2021] [Accepted: 08/30/2021] [Indexed: 06/13/2023]
Abstract
This study evaluates the patient radiation dose from the two-phase protocols of two different computed tomography (CT) systems and compares this with that delivered by the other similar protocols previously published. Two hundred and fourteen patients with primary hyperparathyroidism were included in the study with a two-phase CT scan between 2008 and 2020 by using a Toshiba Aquilion Prime 80 and a GE Light Speed 16. The standard 'neck' or a modified 'parathyroid' protocol was used. The patient dose was evaluated in terms of volumetric computed tomography dose index (CTDIvol), dose length product (DLP) and effective dose (ED) per acquisition protocol and CT system. CTDIvol and DLP were recorded retrospectively, while the ED was calculated based on DLP and an appropriate conversion coefficient. Comparisons of patient dose between the two protocols and two CT systems and the corresponding published values were established. A significantly lower patient dose (40.2-43.2%) than the GE system (p < 0.0001) resulted from the Toshiba system. The 'parathyroid' protocol resulted in a 6.5-9.6% lower patient dose than the standard 'neck' protocol. Compared with the literature, the lowest ED value (3.6 mSv) was observed since this protocol consists of a lowered tube voltage of 100 kVp, a reduced scan length for the pre-contrast phase and implementation of an iterative reconstruction algorithm.
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Affiliation(s)
- Christos P Dimitroukas
- Department of Medical Physics, School of Medicine, University of Patras, Patras 265 04, Greece
- Department of Medical Physics, University Hospital of Patras, Patras 265 04, Greece
| | - Vasileios I Metaxas
- Department of Medical Physics, School of Medicine, University of Patras, Patras 265 04, Greece
| | - Fotios O Efthymiou
- Department of Medical Physics, School of Medicine, University of Patras, Patras 265 04, Greece
| | - Petros E Zampakis
- Department of Radiology, School of Medicine, University of Patras, Patras 265 04, Greece
- Department of Radiology, University Hospital of Patras, Patras 265 04, Greece
| | - Christina P Kalogeropoulou
- Department of Radiology, School of Medicine, University of Patras, Patras 265 04, Greece
- Department of Radiology, University Hospital of Patras, Patras 265 04, Greece
| | - George S Panayiotakis
- Department of Medical Physics, School of Medicine, University of Patras, Patras 265 04, Greece
- Department of Medical Physics, University Hospital of Patras, Patras 265 04, Greece
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Suliman II, Bashier EH, Awad M, Ahmed I, Mohamed S, Ahmed NA. NATIONAL DIAGNOSTIC REFERENCE LEVELS AND ACHIEVABLE DOSES FOR STANDARD CT EXAMINATIONS IN SUDAN. RADIATION PROTECTION DOSIMETRY 2021; 196:1-9. [PMID: 34415339 DOI: 10.1093/rpd/ncab123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 06/14/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
Radiation doses were determined to propose national diagnostic reference levels (NDRLs) and achievable doses (ADs) for computed tomography (CT) examinations in Sudan. Doses were estimated from retrospectively collected scan parameters for 1336 CT examinations of adult patients from 14 Sudanese hospitals using CT Expo 2.5 software. ADs and NDRLs were set at the 50th and 75th percentile of the hospital median dose distribution, respectively. The proposed CTDIvol (mGy) ADs ranged from: 10 (chest) to 64 (head), and that of the dose-length product (DLP; mGy.cm) ranged from 366 (chest) to 1225 (head). The proposed CTDIvol (mGy) NDRLs ranged from 15 kidney-ureter-bladder (KUB) to 79 (head), whereas that of the DLP (mGy.cm) ranged from 690 (chest) to 1490 (head). Current doses fell within the upper range of the doses presented in the literature emphasizing the need for implementation of the current ADs and NDRLs for CT to enhance patient protection and dose optimization in Sudan.
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Affiliation(s)
- I I Suliman
- Imam Mohammad Ibn Saud Islamic University (IMSIU), College of Science, Department of Physics, Riyadh 11642, Saudi Arabia
- Sudan Atomic Energy Commission, Radiation and Nuclear Safety Institute, PO Box 3001, Khartoum, Sudan
| | - Einas H Bashier
- Sudan Atomic Energy Commission, Radiation and Nuclear Safety Institute, PO Box 3001, Khartoum, Sudan
| | - Mustafa Awad
- Sudan Atomic Energy Commission, Radiation and Nuclear Safety Institute, PO Box 3001, Khartoum, Sudan
| | - Ibrahim Ahmed
- Sudan Atomic Energy Commission, Radiation and Nuclear Safety Institute, PO Box 3001, Khartoum, Sudan
| | - Suhair Mohamed
- Sudan Atomic Energy Commission, Radiation and Nuclear Safety Institute, PO Box 3001, Khartoum, Sudan
| | - Nada A Ahmed
- Sudan Atomic Energy Commission, Radiation and Nuclear Safety Institute, PO Box 3001, Khartoum, Sudan
- Taibah University, Faculty of Science, P.O. Box 344, Al-Madinah, Saudi Arabia
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Pennati F, Salito C, Borzani I, Carrafiello G, Morlacchi LC, Vaira V, Nosotti M, Palleschi A, Aliverti A. Quantitative Multivolume Proton-Magnetic Resonance Imaging in Lung Transplant Recipients: Comparison With Computed Tomography and Spirometry. Acad Radiol 2021; 28:e297-e305. [PMID: 32653430 DOI: 10.1016/j.acra.2020.05.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/13/2020] [Accepted: 05/28/2020] [Indexed: 01/07/2023]
Abstract
RATIONALE AND OBJECTIVES Acute and chronic graft rejection remains the major problem in clinical surveillance of lung-transplanted patients and early detection of complications is of capital importance to allow the optimal therapeutic option. The aim of this study was to investigate the role of quantitative non contrast-enhanced magnetic resonance imaging (MRI) as a non-ionizing imaging modality to assess ventilation impairment in patients who have undergone lung transplantation, in comparison with quantitative computed tomography (CT) and spirometry. MATERIALS AND METHODS Ten lung-transplanted patients (39 ±12 years, forced-expiratory volume in 1 second (FEV1) = 81 ± 27%, forced vital capacity (FVC) = 87 ± 27%) were acquired in breath-hold at full-expiration and full-inspiration with 1.5T MRI and CT. Maps of expiratory-inspiratory difference in MR signal-intensity and CT-density were computed to estimate regional ventilation. Based on expiratory, inspiratory, and expiratory-inspiratory difference values, each pixel was classified as healthy (H), low ventilation (LV), air trapping (AT), and consolidation (C) and the percent extent of each class was quantified. RESULTS Overall, expiratory-inspiratory difference in MR signal-intensity correlated to CT-density (r = 0.64, p < 0.0001) and to FEV1 (ρ = 0.71, p = 0.02). The linear correlation between MRI and CT functional maps considering all the four classes is r = 0.93 (p < 0.0001). MRI percent volumes of H, AT, and C correlated to FEV1 %pred, with the highest correlation reported for AT (ρ = -0.82). CONCLUSION Results demonstrated a good agreement between MRI and CT ventilation imaging and between the corresponding percent volumes of lung damage. Quantitative MRI may represent an accurate non-ionizing imaging technique for longitudinal monitoring of lung transplant recipients.
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Eghbali Zarch R, Askari M, boostani H, Mirzaii-Dizgah I. Effect of propolis extract on clinical parameters and salivary level of matrix metalloproteinase 8 in periodontitis patients: A randomized controlled clinical trial. JOURNAL OF ADVANCED PERIODONTOLOGY & IMPLANT DENTISTRY 2021; 13:84-89. [PMID: 35919679 PMCID: PMC9327480 DOI: 10.34172/japid.2021.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 09/14/2021] [Indexed: 11/09/2022]
Abstract
Background. Periodontitis is the bacterial-induced inflammation of tooth-supporting structures. Local antibacterial agents are used as adjunctive therapy in the treatment of periodontitis. This study aimed to compare the effect of subgingivally delivered propolis extract (a resin produced by honey bees) with chlorhexidine (CHX) mouthwash on clinical parameters and salivary levels of matrix metalloproteinase 8 (MMP-8) in periodontitis patients.Methods. Twenty-eight periodontitis patients in stage II or III and grade B, who had deep periodontal pockets (≥4 mm) around at least three non-adjacent teeth, were divided into two groups. In the control group, patients were prescribed 0.2% CHX mouthwash twice a day for two weeks. In the 20% propolis hydroalcoholic group, subgingival irrigation was performed twice a week for two weeks. Clinical parameters were measured at baseline and after two months. Salivary samples were collected from the propolis and control groups at baseline and two months later to assess MMP-8 levels using the enzyme-linked immunosorbent assay. Additionally, salivary samples from 12 periodontally healthy subjects were used to determine the normal levels of MMP-8. The data were analyzed using SPSS. P<0.05 was considered the level of significance.Results. In the healthy group, the mean salivary levels of MMP-8 were significantly lower than that in the control and propolis groups at baseline (P<0.001). The results indicated a significant improvement in clinical parameters (P<0.001) in the propolis group compared to the control group, while MMP-8 levels decreased significantly in both groups (P<0.001).Conclusion. Propolis is recommended as adjunctive therapy for periodontitis patients. Clinical trials registration code: IRCT2016122030475N3.
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Affiliation(s)
| | - Mitra Askari
- Oral and Maxillofacial Pathology Department, Faculty of Dentistry, Tehran University of Medical Sciences, International Campus, Tehran, Iran
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Tan XM, Shah MTBM, Chong SL, Ong YKG, Ang PH, Zakaria NDB, Lee KP, Pek JH. Differences in radiation dose for computed tomography of the brain among pediatric patients at the emergency departments: an observational study. BMC Emerg Med 2021; 21:106. [PMID: 34551720 PMCID: PMC8456576 DOI: 10.1186/s12873-021-00502-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 09/13/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Computed tomography (CT) is associated with a risk of cancer development. Strategies to reduce radiation doses vary between centers. We compared radiation doses of CT brain studies between pediatric and general emergency departments (EDs), and determine the proportion studies performed within the reference levels recommended by the International Commission on Radiological Protection (ICRP). METHODS A retrospective review was carried out in a healthcare network consisting of one pediatric ED and three general hospital EDs. Pediatric patients less than 16 years old with CT brain studies performed between 1 January 2015 and 31 December 2018 were included. Information on demographic, diagnosis, volume-averaged computed-tomography dose index and dose length product (DLP) were collected. Effective dose was then calculated from DLP using conversion factors, termed k-coefficients which were derived using a 16 cm head CT dose phantom. RESULTS Four hundred and seventy-nine CT brain studies were performed - 379 (79.1%) at the pediatric ED. Seizure (149, 31.1%), head injury (147, 30.7%) and altered mental status (44, 9.2%) were the top three ED diagnoses. The median effective dose estimates were higher in general than pediatric EDs, particularly for those aged > 3 to ≤6 years old [1.57 mSv (IQR 1.42-1.79) versus 1.93 mSv (IQR 1.51-2.28), p = 0.047], > 6 to ≤10 years old [1.43 mSv (IQR 1.27-1.67) versus 1.94 mSv (IQR 1.61-2.59), p = 0.002) and > 10 years old (1.68 mSv (IQR 1.32-1.72) versus 2.03 mSv (IQR 1.58-2.88), p < 0.001). Overall, 233 (48.6%) and 13 (2.7%) studies were within the reference levels recommended by ICRP 60 and 103 respectively. CONCLUSIONS Radiation doses for CT brain studies were significantly higher at general EDs and less than half of the studies were within the reference levels recommended by ICRP. The development of diagnostic reference levels (DRLs) as a benchmark and clinical justification for performing CT studies can help reduce the radiation risks in the pediatric population.
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Affiliation(s)
- Xi Min Tan
- Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Dr, Singapore, 117597, Singapore
| | | | - Shu-Ling Chong
- Department of Emergency Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Rd, Singapore, 229899, Singapore
| | - Yong-Kwang Gene Ong
- Department of Emergency Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Rd, Singapore, 229899, Singapore
| | - Peck Har Ang
- Accident and Emergency Department, Changi General Hospital, 2 Simei Street 3, Singapore, 529889, Singapore
| | - Nur Diana Bte Zakaria
- Department of Emergency Medicine, Singapore General Hospital, Outram Rd, Singapore, 169608, Singapore
| | - Khai Pin Lee
- Department of Emergency Medicine, KK Women's and Children's Hospital, 100 Bukit Timah Rd, Singapore, 229899, Singapore
| | - Jen Heng Pek
- Department of Emergency Medicine, Sengkang General Hospital, 110 Sengkang E Way, Singapore, 544886, Singapore.
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Campelo DAM, Asfora VK, Barros VSMD, Renha SK, Khoury HJ. Scan factors and practices associated with radiation doses for chest CT: current Brazilian scenario. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2021; 41:481-494. [PMID: 33721853 DOI: 10.1088/1361-6498/abee95] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
The main purpose of this study was to compare the parameters of computed tomography (CT) and the corresponding patient doses undergoing chest CT scan examinations in different regions of Brazil, providing the current scenario of how these procedures are being carried out in the country as well as the patient dose distribution. Thirty institutions, across 17 states and the Federal District, participated in the survey. The evaluation included 30 multislice CTs of seven different models, manufactured by General Electric (GE) Healthcare. For each institution, data from 10 adult chest CT examinations, performed without contrast, were collected remotely. The analysis of the results showed a significant difference of the CTDIvolvalues, ranging from 1.1 mGy to 46.6 mGy in seven institutions. The mean value of CTDIvolwas higher than values found in the literature and the UK Reference Levels. It was also observed that, regardless of the region of the country, for the same CT model, different scanning parameters were used, which resulted in CTDIvolup to 5 times higher in some institutions. Repetitions of CT acquisitions and scouts with radiation field dimensions larger than the region of interest were found in 25% of chest examinations, resulting in higher absorbed doses. The results of this work show a mapping of the chest CT procedures, which enables the establishment of strategic plans for the country. In addition, each institution will be able to implement an appropriate optimization program and establish institutional reference levels.
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Affiliation(s)
- D A M Campelo
- Nuclear Energy Department, Federal University of Pernambuco, Recife, PE, Brazil
| | - V K Asfora
- Nuclear Energy Department, Federal University of Pernambuco, Recife, PE, Brazil
| | - V S M D Barros
- Nuclear Energy Department, Federal University of Pernambuco, Recife, PE, Brazil
| | - S K Renha
- Institute of Radiation Protection and Dosimetry, National Commission of Nuclear Energy, Rio de Janeiro, RJ, Brazil
| | - H J Khoury
- Nuclear Energy Department, Federal University of Pernambuco, Recife, PE, Brazil
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Behroozian A, Kalman L, Hemmatiyan M. Inclinometer: A new device for measuring intermolar torque and angle. JOURNAL OF ADVANCED PERIODONTOLOGY & IMPLANT DENTISTRY 2021; 13:97-99. [PMID: 35919676 PMCID: PMC9327474 DOI: 10.34172/japid.2021.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022]
Abstract
The torque of posterior teeth is of great importance in esthetics and occlusion. In the present article, we introduce a simple but useful device to measure intermolar torque. The device consists of two movable and adjustable arms that lie on the selected molar teeth bilaterally; the graduated plane at the body of the appliance then shows the intermolar torque. This device can measure intermolar torque easily and rapidly, with high validity and at a low cost.
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Affiliation(s)
- Ahmad Behroozian
- Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Les Kalman
- Restorative Dentistry Chair, Dental Outreach, Schulich School of Medicine & Dentistry, Western University, Ontario, Canada
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30
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Lasiyah N, Anam C, Hidayanto E, Dougherty G. Automated procedure for slice thickness verification of computed tomography images: Variations of slice thickness, position from iso-center, and reconstruction filter. J Appl Clin Med Phys 2021; 22:313-321. [PMID: 34109738 PMCID: PMC8292687 DOI: 10.1002/acm2.13317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 05/07/2021] [Accepted: 05/17/2021] [Indexed: 11/11/2022] Open
Abstract
Purpose The purpose of this study is to automate the slice thickness verification on the AAPM CT performance phantom and validate it for variations of slice thickness, position from iso‐center, and reconstruction filter. Methods An automatic procedure for slice thickness verification on AAPM CT performance phantom was developed using MATLAB R2015b. The stair object image within the phantom was segmented, and the middle stair object was located. Its angle was determined using the Hough transformation, and the image was rotated accordingly. The profile through this object was obtained, and its full‐width of half maximum (FWHM) was automatically measured. The FWHM indicated the slice thickness of the image. The automated procedure was applied with variations in three independent parameters, i.e., the slice thickness, the distance from the phantom to the iso‐center, and the reconstruction filter. The automated results were compared to manual measurements made using electronic calipers. Results The differences of the automated results from the nominal slice thicknesses were within 1.0 mm. The automated results are comparable to those from manual approach (i.e., the difference of both is within 12%). The automatic procedure accurately obtained slice thickness even when the phantom was moved from the iso‐center position by up to 4 cm above and 4 cm below the iso‐center. The automated results were similar (to within 0.1 mm) for various reconstruction filters. Conclusions We successfully developed an automated procedure of slice thickness verification and confirmed that the automated procedure provided accurate results. It provided an easy and effective method of determining slice thickness.
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Affiliation(s)
- Nani Lasiyah
- Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Semarang, Indonesia
| | - Choirul Anam
- Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Semarang, Indonesia
| | - Eko Hidayanto
- Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Semarang, Indonesia
| | - Geoff Dougherty
- Department of Applied Physics and Medical Imaging, California State University Channel Islands, Camarillo, CA, USA
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Heidarian S, Afshar P, Enshaei N, Naderkhani F, Rafiee MJ, Babaki Fard F, Samimi K, Atashzar SF, Oikonomou A, Plataniotis KN, Mohammadi A. COVID-FACT: A Fully-Automated Capsule Network-Based Framework for Identification of COVID-19 Cases from Chest CT Scans. Front Artif Intell 2021; 4:598932. [PMID: 34113843 PMCID: PMC8186443 DOI: 10.3389/frai.2021.598932] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 02/09/2021] [Indexed: 01/12/2023] Open
Abstract
The newly discovered Coronavirus Disease 2019 (COVID-19) has been globally spreading and causing hundreds of thousands of deaths around the world as of its first emergence in late 2019. The rapid outbreak of this disease has overwhelmed health care infrastructures and arises the need to allocate medical equipment and resources more efficiently. The early diagnosis of this disease will lead to the rapid separation of COVID-19 and non-COVID cases, which will be helpful for health care authorities to optimize resource allocation plans and early prevention of the disease. In this regard, a growing number of studies are investigating the capability of deep learning for early diagnosis of COVID-19. Computed tomography (CT) scans have shown distinctive features and higher sensitivity compared to other diagnostic tests, in particular the current gold standard, i.e., the Reverse Transcription Polymerase Chain Reaction (RT-PCR) test. Current deep learning-based algorithms are mainly developed based on Convolutional Neural Networks (CNNs) to identify COVID-19 pneumonia cases. CNNs, however, require extensive data augmentation and large datasets to identify detailed spatial relations between image instances. Furthermore, existing algorithms utilizing CT scans, either extend slice-level predictions to patient-level ones using a simple thresholding mechanism or rely on a sophisticated infection segmentation to identify the disease. In this paper, we propose a two-stage fully automated CT-based framework for identification of COVID-19 positive cases referred to as the “COVID-FACT”. COVID-FACT utilizes Capsule Networks, as its main building blocks and is, therefore, capable of capturing spatial information. In particular, to make the proposed COVID-FACT independent from sophisticated segmentations of the area of infection, slices demonstrating infection are detected at the first stage and the second stage is responsible for classifying patients into COVID and non-COVID cases. COVID-FACT detects slices with infection, and identifies positive COVID-19 cases using an in-house CT scan dataset, containing COVID-19, community acquired pneumonia, and normal cases. Based on our experiments, COVID-FACT achieves an accuracy of 90.82%, a sensitivity of 94.55%, a specificity of 86.04%, and an Area Under the Curve (AUC) of 0.98, while depending on far less supervision and annotation, in comparison to its counterparts.
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Affiliation(s)
- Shahin Heidarian
- Department of Electrical and Computer Engineering, Concordia University, Montreal, QC, Canada
| | - Parnian Afshar
- Concordia Institute for Information Systems Engineering (CIISE), Concordia University, Montreal, QC, Canada
| | - Nastaran Enshaei
- Concordia Institute for Information Systems Engineering (CIISE), Concordia University, Montreal, QC, Canada
| | - Farnoosh Naderkhani
- Concordia Institute for Information Systems Engineering (CIISE), Concordia University, Montreal, QC, Canada
| | - Moezedin Javad Rafiee
- Department of Medicine and Diagnostic Radiology, McGill University Health Center-Research Institute, Montreal, QC, Canada
| | - Faranak Babaki Fard
- Biomedical Sciences Department, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
| | - Kaveh Samimi
- Department of Radiology, Iran University of Medical Science, Tehran, Iran
| | - S Farokh Atashzar
- Department of Electrical and Computer Engineering, New York University, New York, NY, United States.,Department of Mechanical and Aerospace Engineering, New York University, New York, NY, United States
| | - Anastasia Oikonomou
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | | | - Arash Mohammadi
- Concordia Institute for Information Systems Engineering (CIISE), Concordia University, Montreal, QC, Canada
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Murthy A, Kornel E, Neubardt S. Strategy to reduce radiation exposure in postoperative spinal computed tomography scans. Surg Neurol Int 2021; 12:159. [PMID: 33948329 PMCID: PMC8088488 DOI: 10.25259/sni_289_2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/28/2020] [Indexed: 12/14/2022] Open
Abstract
Background: When diagnosing and treating spinal disorders, spine surgeons commonly utilize computed tomography (CT) scans preoperatively, intraoperatively, and postoperatively. Methods: This article reviews the literature regarding the potentially harmful effects of X-rays, specifically from CT scans. Results: The risk for damaging DNA and developing cancer increases with increasing scan length (e.g., increasing amount of radiation received). Conclusion: When assessing postoperative status, CT scans should be directed only through the area of specific interest to limit the total dose of radiation received by the patient.
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Affiliation(s)
- Anirudh Murthy
- Department of Biology, Stony Brook University, Stony Brook
| | | | - Seth Neubardt
- Department of Orthopedic Surgery, Brain and Spine Surgeons of New York, West Harrison, New York, United States
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Zawam Dalah E, Dhou S, Mudalige T, Amin F, Obaideen A. Challenges estimating patient organs doses undergoing enhanced chest CT examination: exploratory study. Biomed Phys Eng Express 2021; 7. [PMID: 33588398 DOI: 10.1088/2057-1976/abe68e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/15/2021] [Indexed: 11/11/2022]
Abstract
Purpose: Estimate organs doses (ODs) of patients subjected to unenhanced (S1) and enhanced (S2) chest CT studies relying on image parameters such as Hounsfield Units (HUs).Materials and Methods: CT scans and images of a total of 16 patients who underwent two series of chest CT studies were obtained and retrospectively examined. OD increments of liver and pancreas for both series (S1 & S2) were estimated using two different independent methods, namely simulation approach using CT-EXPO and Amato's phantom-based fitting model (APFM). HUs were quantified for each organ by manually drawing fixed area-sized regions of interest (ROIs). The mean HUs were collected to obtain the ODs increments following APFM. Regression analysis was applied to find and assess the relationship between the HUs and the OD increments estimated using APFM and that using CT-EXPO. Spearman Coefficient and Wilcoxon Matched Pairedt-testwere conducted to show statistical correlation and difference between ODs increments using the two methods.Results:A strong significant difference was depicted between S1 and S2 scan series of liver and pancreas using CT-EXPO simulation. Mean HU values for S1 were lower than S2, resulting in statistically significant (p < 0.0001) HU changes. CT-EXPO simulation yielded significantly higher difference in ODs compared to the APFM for liver (p = 0.0455) and pancreas (p = 0.0031). Regression analysis revealed a strong relationship between HU of S1 and S2 and ODs increments using APFM in both organs (R2 = 0.99), dissimilar to CT-EXPO (R2 = 0.39 in liver andR2 = 0.05 in pancreas).Conclusions: Although CT-EXPO allows for estimating ODs accounting for major acquisition scan parameters, it is not a reliable tool to evaluate the impact of contrast enhancement on ODs. On the other hand, the APFM accounts for contrast enhancement accumulation yet only provides relative OD increments, an information of limited clinical use.
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Affiliation(s)
- Entesar Zawam Dalah
- Department of Clinical Support Services and Nursing Sector, Dubai Health Authority, Dubai, UAE.,Department of Medical Diagnostic Imaging, University of Sharjah, Sharjah, UAE
| | - Salam Dhou
- Department of Computer Science and Engineering, American University of Sharjah, Sharjah, UAE
| | - Thilini Mudalige
- Department of Medical Diagnostic Imaging, University of Sharjah, Sharjah, UAE
| | - Fatima Amin
- Department of Medical Diagnostic Imaging, University of Sharjah, Sharjah, UAE
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Koudrina A, O'Brien J, Garcia R, Boisjoli S, Kan PTM, Tsai EC, DeRosa MC. Assessment of Aptamer-Targeted Contrast Agents for Monitoring of Blood Clots in Computed Tomography and Fluoroscopy Imaging. Bioconjug Chem 2020; 31:2737-2749. [PMID: 33232126 DOI: 10.1021/acs.bioconjchem.0c00525] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Objective: Random formation of thrombi is classified as a pathological process that may result in partial or complete obstruction of blood flow and limited perfusion. Further complications include pulmonary embolism, thrombosis-induced myocardial infraction, ischemic stroke, and others. Location and full delineation of the blood clot are considered to be two clinically relevant aspects that could streamline proper diagnosis and treatment follow-up. In this work, we prepared two types of X-ray attenuating contrast formulations, using fibrinogen aptamer as the clot-seeking moiety. Methods: Two novel aptamer-targeted formulations were designed. Iodine-modified bases were directly incorporated into a fibrinogen aptamer (iodo-FA). Isothermal titration calorimetry was used to confirm that these modifications did not negatively impact target binding. Iodo-FA was tested for its ability to produce concentration-dependent contrast enhancement in a phantom CT. It was subsequently tested in vitro with clotted human and swine blood. This allowed for translation into ex vivo testing, using fluoroscopy. FA was also used to functionalize gold nanoparticles (FA-AuNPs), and contrast capabilities were confirmed. This formulation was tested in vitro using clotted human blood in a CT scan. Results: Unmodified FA and iodo-FA demonstrated a nearly identical affinity toward fibrin, confirming that base modifications did not impact target binding. Iodo-FA and FA-AuNPs both demonstrated excellent concentration-dependent contrast enhancement capabilities (40.5 HU mM-1 and 563.6 HU μM-1, respectively), which were superior to the clinically available agent, iopamidol. In vitro CT testing revealed that iodo-FA is able to penetrate into the blood clots, producing contrast enhancement throughout, while FA-AuNPs only accumulated on the surface of the clot. Iodo-FA was thereby translated to ex vivo testing, confirming target-binding associated accumulation of the contrast material at the location of the clot within the dilation of the external carotid artery. This resulted in a 34% enhancement of the clot. Conclusions: Both iodo-FA and FA-AuNPs were confirmed to be effective contrast formulations in CT. Targeting of fibrin, a major structural constituent of thrombi, with these novel contrast agents would allow for higher contrast enhancement and better clot delineation in CT and fluoroscopy.
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Affiliation(s)
- Anna Koudrina
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | | | - Roberto Garcia
- Department of Neurosurgery, The University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555, United States
| | - Spencer Boisjoli
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | - Peter T M Kan
- Department of Neurosurgery, The University of Texas Medical Branch, 301 University Boulevard, Galveston, Texas 77555, United States
| | - Eve C Tsai
- The Ottawa Hospital, Ottawa, ON K1Y 4E9, Canada.,Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada.,Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Maria C DeRosa
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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Performance evaluation of near-real time angular tube current modulation in X-ray computed tomography using real-time dosimeter: a phantom study. HEALTH AND TECHNOLOGY 2020. [DOI: 10.1007/s12553-020-00473-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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36
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van der Merwe CM, Mahomed N. An audit of radiation doses received by paediatric patients undergoing computed tomography investigations at academic hospitals in South Africa. SA J Radiol 2020; 24:1823. [PMID: 33240540 PMCID: PMC7669994 DOI: 10.4102/sajr.v24i1.1823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 05/29/2020] [Indexed: 11/29/2022] Open
Abstract
Background Diagnostic reference levels (DRLs) are a crucial element of auditing radiation doses in paediatric computed tomography (CT). Currently, there are no national paediatric CT DRLs in South Africa. Objectives The aim of this article was to establish local paediatric DRLs for CT examinations at two academic hospitals and to compare paediatric CT radiation output levels with established DRLs in the developed and developing world. Method Computed Tomography Dose Indexvolume (CTDIvol) and dose length product (DLP) values were collected from CT examinations performed at two university hospitals for patients aged 0–15 years, during 01 November 2016–30 April 2017. The 75th percentile of the data distribution was calculated for each CT examination type and age group, further categorised into routine working hours and after-hours for both hospitals and statistically compared. Results Of the 1031 CT examinations performed, CT brain examination was the most common (755/1031; 72.23%). DLP values were increased in the after-hours categories compared to regular working hours at both hospitals. The largest increase was in the 0–1 year age group (150.56%). With the exception of CT Chest and CT abdomen in the 0–1 year age group, the CTDIvol and DLP values compared favourably to international standards. Conclusion Most of the calculated DRLs are acceptable and internationally comparable. This likely indicates effective reduction techniques and protocols. Computed tomography body examination protocols for 0–1 year patients should be reviewed. Strategies should be implemented to limit higher doses in after-hours examinations.
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Affiliation(s)
- Cornelis M van der Merwe
- Department of Radiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nasreen Mahomed
- Department of Radiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Kada S. Knowledge of CT exposure parameters among Norwegian student radiographers. BMC MEDICAL EDUCATION 2020; 20:302. [PMID: 32928205 PMCID: PMC7491127 DOI: 10.1186/s12909-020-02233-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Improvements in the competency levels of student radiographers in computed tomography examinations (CT) are important due to the increasing number of these examinations being undertaken in imaging departments. The present study assesses the knowledge of student radiographers regarding CT exposure parameters. METHODS The level of knowledge related to CT exposure parameters was evaluated using a twenty-one-item questionnaire that was distributed to final-year student radiographers. The questionnaire consisted of questions around CT exposure parameters and either allowed respondents to answer "true," or "false" or choose a response from a range of responses where only one answer was correct. Correct answers were given one mark, while no mark was given for an incorrect answer. The score out of possible 21 was converted to a percentage, with a higher percentage signifying greater knowledge. RESULTS Seventy-two students completed and returned the questionnaire, resulting in a 71% response rate. The mean score was 53%. Only 33% of students correctly identified that kilovoltage peak (kVp) should be increased when patients have metallic implants, and milliampere seconds (mAs) should be increased as body part thickness increases. No one answered all the questions correctly. There was no significant knowledge difference between students who had CT facilities on campus and those that did not. CONCLUSION Overall, student radiographers' knowledge of CT exposure parameters was reported to be satisfactory.
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Affiliation(s)
- Sundaran Kada
- Faculty of Health and Social Sciences, Western Norway University of Applied Sciences, Post Box 7030, 5020, Bergen, Norway.
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38
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Theilig D, Mayerhofer A, Petschelt D, Elkilany A, Hamm B, Gebauer B, Geisel D. Impact of interventionalist's experience and gender on radiation dose and procedural time in CT-guided interventions-a retrospective analysis of 4380 cases over 10 years. Eur Radiol 2020; 31:569-579. [PMID: 32851446 PMCID: PMC8263432 DOI: 10.1007/s00330-020-07185-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/30/2020] [Accepted: 08/12/2020] [Indexed: 11/09/2022]
Abstract
Objectives To investigate the impact of the interventionalist’s experience and gender on radiation dose and procedural time in CT-guided interventions. Methods We retrospectively analyzed 4380 CT-guided interventions performed at our institution with the same CT scanner from 2009 until 2018, 1287 (29%) by female and 3093 (71%) by male interventionalists. Radiation dose, number of CT fluoroscopy images taken per intervention, total procedural time, type of intervention, and degree of difficulty were derived from the saved dose reports and images. All 16 interventionalists included in this analysis performed their first CT-guided interventions during the study period, and interventions performed by each interventionalist were counted to assess the level of experience for each intervention in terms of the number of prior interventions performed by her or him. The Mann-Whitney U test (MWU test), multivariate regression, and linear mixed model analysis were performed. Results Assessment of the impact of gender with the MWU test revealed that female interventionalists took a significantly smaller number of images (p < 0.0001) and achieved a lower dose-length product per intervention (p < 0.0001) while taking more time per intervention (p = 0.0001). This finding was confirmed for most types of interventions when additionally accounting for other possible impact factors in multivariate regression analysis. In linear mixed model analysis, we found that radiation dose, number of images taken per intervention, and procedural time decreased statistically significantly with interventionalist’s experience. Conclusions Radiation doses of CT-guided interventions are reduced by interventionalist’s experience and, for most types of interventions, when performed by female interventionalists. Key Points • Radiation doses in CT-guided interventions are lower when performed by female interventionalists. • Procedural times of CT-guided interventions are longer when performed by female interventionalists. • Radiation doses of CT-guided interventions decrease with the interventionalist’s experience. Electronic supplementary material The online version of this article (10.1007/s00330-020-07185-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dorothea Theilig
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Anna Mayerhofer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany
| | - David Petschelt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Aboelyazid Elkilany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Bernd Hamm
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Bernhard Gebauer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Dominik Geisel
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Diagnostic and Interventional Radiology, Augustenburger Platz 1, 13353, Berlin, Germany
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Zhou Y, Xu X, Song L, Wang C, Guo J, Yi Z, Li W. The application of artificial intelligence and radiomics in lung cancer. PRECISION CLINICAL MEDICINE 2020; 3:214-227. [PMID: 35694416 PMCID: PMC8982538 DOI: 10.1093/pcmedi/pbaa028] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 02/05/2023] Open
Abstract
Lung cancer is one of the most leading causes of death throughout the world, and there is an urgent requirement for the precision medical management of it. Artificial intelligence (AI) consisting of numerous advanced techniques has been widely applied in the field of medical care. Meanwhile, radiomics based on traditional machine learning also does a great job in mining information through medical images. With the integration of AI and radiomics, great progress has been made in the early diagnosis, specific characterization, and prognosis of lung cancer, which has aroused attention all over the world. In this study, we give a brief review of the current application of AI and radiomics for precision medical management in lung cancer.
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Affiliation(s)
- Yaojie Zhou
- Department of Respiratory and Critical Care Medicine, West China School of Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiuyuan Xu
- Machine Intelligence Laboratory, College of Computer Science, Sichuan University, Chengdu 610065, China
| | - Lujia Song
- West China School of Public Health, Sichuan University, Chengdu 610041, China
| | - Chengdi Wang
- Department of Respiratory and Critical Care Medicine, West China School of Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Jixiang Guo
- Machine Intelligence Laboratory, College of Computer Science, Sichuan University, Chengdu 610065, China
| | - Zhang Yi
- Machine Intelligence Laboratory, College of Computer Science, Sichuan University, Chengdu 610065, China
| | - Weimin Li
- Department of Respiratory and Critical Care Medicine, West China School of Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
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Best practice for the nuclear medicine technologist in CT-based attenuation correction and calcium score for nuclear cardiology. Eur J Hybrid Imaging 2020; 4:11. [PMID: 34191150 PMCID: PMC8218053 DOI: 10.1186/s41824-020-00080-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 06/16/2020] [Indexed: 12/12/2022] Open
Abstract
The use of hybrid systems is increasingly growing in Europe and this is progressively important for the final result of diagnostic tests. As an integral part of the hybrid imaging system, computed tomography (CT) plays a crucial role in myocardial perfusion imaging diagnostics. Throughout Europe, a variety of equipment is available and also different university curricula of the nuclear medicine technologist are observed. Hence, the Technologist Committee of the European Association of Nuclear Medicine proposes to identify, through a bibliographic review, the recommendations for best practice in computed tomography applied to attenuation correction and calcium score in myocardial perfusion imaging, which courses in the set of knowledge, skills, and competencies for nuclear medicine technologists. This document aims at providing recommendations for CT acquisition protocols and CT image optimization in nuclear cardiology.
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Abadi E, Segars WP, Harrawood B, Sharma S, Kapadia A, Samei E. Virtual clinical trial for quantifying the effects of beam collimation and pitch on image quality in computed tomography. J Med Imaging (Bellingham) 2020; 7:042806. [PMID: 32509918 PMCID: PMC7262564 DOI: 10.1117/1.jmi.7.4.042806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 05/19/2020] [Indexed: 01/06/2023] Open
Abstract
Purpose: To utilize a virtual clinical trial (VCT) construct to investigate the effects of beam collimation and pitch on image quality (IQ) in computed tomography (CT) under different respiratory and cardiac motion rates. Approach: A computational human model [extended cardiac-torso (XCAT) phantom] with added lung lesions was used to simulate seven different rates of cardiac and respiratory motions. A validated CT simulator (DukeSim) was used in this study. A supplemental validation was done to ensure the accuracy of DukeSim across different pitches and beam collimations. Each XCAT phantom was imaged using the CT simulator at multiple pitches (0.5 to 1.5) and beam collimations (19.2 to 57.6 mm) at a constant dose level. The images were compared against the ground truth using three task-generic IQ metrics in the lungs. Additionally, the bias and variability in radiomics (morphological) feature measurements were quantified for task-specific lung lesion quantification across the studied imaging conditions. Results: All task-generic metrics degraded by 1.6% to 13.3% with increasing pitch. When imaged with motion, increasing pitch reduced motion artifacts. The IQ slightly degraded (1.3%) with changes in the studied beam collimations. Patient motion exhibited negative effects (within 7%) on the IQ. Among all features across all imaging conditions studies, compactness2 and elongation showed the largest ( - 26.5 % , 7.8%) and smallest ( - 0.8 % , 2.7%) relative bias and variability. The radiomics results were robust across the motion profiles studied. Conclusions: While high pitch and large beam collimations can negatively affect the quality of CT images, they are desirable for fast imaging. Further, our results showed no major adverse effects in morphology quantification of lung lesions with the increase in pitch or beam collimation. VCTs, such as the one demonstrated in this study, represent a viable methodology for experiments in CT.
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Affiliation(s)
- Ehsan Abadi
- Duke University School of Medicine, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States
| | - William P. Segars
- Duke University School of Medicine, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States
- Duke University School of Medicine, Medical Physics Graduate Program, Durham, North Carolina, United States
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Brian Harrawood
- Duke University School of Medicine, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States
| | - Shobhit Sharma
- Duke University School of Medicine, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States
- Duke University, Department of Physics, Durham, North Carolina, United States
| | - Anuj Kapadia
- Duke University School of Medicine, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States
- Duke University School of Medicine, Medical Physics Graduate Program, Durham, North Carolina, United States
- Duke University, Department of Physics, Durham, North Carolina, United States
| | - Ehsan Samei
- Duke University School of Medicine, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Durham, North Carolina, United States
- Duke University School of Medicine, Medical Physics Graduate Program, Durham, North Carolina, United States
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
- Duke University, Department of Physics, Durham, North Carolina, United States
- Duke University, Department of Electrical and Computer Engineering, Durham, North Carolina, United States
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Poehler GH, Alikhani B, Klimes F, Hauck EF, Ringe KI, Sonnow L, Wacker F, Raatschen HJ. Impact of active dose management on radiation exposure and image quality in computed tomography: An observational study in 1315 patients. Eur J Radiol 2020; 125:108900. [DOI: 10.1016/j.ejrad.2020.108900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 11/17/2022]
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Chest CTA in children younger than two years - a retrospective comparison of three contrast injection protocols. Sci Rep 2019; 9:18109. [PMID: 31792291 PMCID: PMC6889233 DOI: 10.1038/s41598-019-54498-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/14/2019] [Indexed: 12/26/2022] Open
Abstract
To obtain the highest diagnostic information with least side effects when performing thoracic CT angiography (CTA) is challenging in young children. The current study aims to compare three contrast agent (CA) injection protocols regarding image quality and CA characteristic: a standard CTA, a fixed-bolus delay protocol, and the “microbolus technique (MBT)” developed in our institution. Seventy chest CTA scans of patients (<2 years) were divided into three groups. MBT was applied in group I, the standard protocol in group II and a fixed bolus delay in group III. Objective image quality was assessed by measuring peak enhancement, image noise, signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Two observers scored subjective image quality and artifacts. Significantly lower amounts of CA (mean ± SD) were used in the MBT group compared to Group II (9.0 ± 3.7 ml vs. 12.9 ± 4.5 ml). A lower, but still diagnostic (>400 HU) enhancement was registered in all major thoracic vessels in group I without significant differences regarding SNR and CNR in most regions (p < 0.05). The best scores for image quality and artifacts were reached in group I. All three chest CTA contrast injection protocols offered diagnostic vessel enhancement in young patients. MBT was associated with reduced image artifacts and less injected CA.
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Ren Z, Zhang X, Hu Z, Li D, Liu Z, Wei D, Jia Y, Yu N, Yu Y, Lei Y, Chen X, Guo C, Ren Z, He T. Application of Adaptive Statistical Iterative Reconstruction-V With Combination of 80 kV for Reducing Radiation Dose and Improving Image Quality in Renal Computed Tomography Angiography for Slim Patients. Acad Radiol 2019; 26:e324-e332. [PMID: 30655053 DOI: 10.1016/j.acra.2018.12.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/23/2018] [Accepted: 12/24/2018] [Indexed: 01/22/2023]
Abstract
OBJECTIVES To explore the application of adaptive statistical iterative reconstruction-V (ASIR-V) with combination of 80 kV for reducing radiation dose and improving image quality in renal computed tomography angiography (CTA) for slim patients compared with traditional filtered back projection (FBP) reconstruction using 120 kV. METHODS Eighty patients for renal CTA were prospectively enrolled and randomly divided into group A and group B. Group A used 120 kV and 600 mgI/kg contrast agent and FBP reconstruction, while group B used 80 kV and 350 mgI/kg contrast agent and both FBP and ASIR-V reconstruction from 10%ASIR-V to 100%ASIR-V with 10%ASIR-V interval. The CT values and SD values of the right renal artery and left renal artery were measured to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The image quality was subjectively scored by two experienced radiologists blindly using a five-point criterion. The contrast agent, volumetric CT dose index (CTDIvol), and dose length product in both groups were recorded and the effective radiation dose was calculated. RESULTS There were no significant difference in patient characteristics between two groups (p > 0.05). The CTDIvol, dose length product and effective radiation dose in group B were 59.0%, 65.0%, and 65.1% lower than those in group A, respectively (all p < 0.05), and the contrast agent in group B was 42.2% lower than that in group A (p < 0.05). In group B, with the increase of ASIR-V percentage, CT values showed no significant difference, SD values decreased gradually, SNR values and CNR values increased gradually. The CT values showed no statistically significant difference (p > 0.05) between two groups with different reconstructions. The SD values with 40%ASIR-V to 100%ASIR-V reconstruction in group B was significantly lower(p < 0.5), while the SNR values with 50% ASIR-V to 100% ASIR-V reconstruction and CNR values with 70%ASIR-V to 100%ASIR-V were significantly higher than those of group A with FBP reconstruction (p < 0.5). Two radiologists had excellent consistency in subjective scores of image quality for renal CTA (kappa >0.75, p < 0.05). The subjective scores with 60% ASIR-V to 90% ASIR-V in group B were significantly higher than those of FBP in group A (p < 0.5), of which 70%ASIR-V reconstruction obtained the highest subjective score for renal CTA. CONCLUSION ASIR-V with combination of 80 kV can significantly reduce effective radiation dose (about 65.1%) and contrast agent (about 42.2%) and improve image quality in renal CTA for slim patients compared with traditional FBP reconstruction using 120 kV, and the 70% ASIR-V was the best reconstruction algorithm in 80 kV renal CTA. ADVANCES IN KNOWLEDGE Using 80 kV with combination of ASIR-V can significantly reduce radiation dose and contrast agent dose as well as improve image quality in renal CTA for thin patients when compared with FBP using 120 kV.
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Affiliation(s)
- Zhanli Ren
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000; Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China; The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Xirong Zhang
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000
| | - Zhijun Hu
- Department of Medical Imaging, Chang'an Hospital, Xi'an, Shaanxi, China
| | - Dou Li
- Department of Medical Imaging, Chang'an Hospital, Xi'an, Shaanxi, China
| | - Zhentang Liu
- Department of Medical Imaging, Chang'an Hospital, Xi'an, Shaanxi, China
| | - Donghong Wei
- Department of Medical Imaging, Chang'an Hospital, Xi'an, Shaanxi, China
| | - Yongjun Jia
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000
| | - Nan Yu
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000
| | - Yong Yu
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000
| | - Yuxin Lei
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000
| | - Xiaoxia Chen
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000
| | - Changyi Guo
- The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China
| | - Zhanliang Ren
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000.
| | - Taiping He
- Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang, Shaanxi, China 712000.
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Wang T, Lei Y, Tian Z, Dong X, Liu Y, Jiang X, Curran WJ, Liu T, Shu HK, Yang X. Deep learning-based image quality improvement for low-dose computed tomography simulation in radiation therapy. J Med Imaging (Bellingham) 2019; 6:043504. [PMID: 31673567 PMCID: PMC6811730 DOI: 10.1117/1.jmi.6.4.043504] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/03/2019] [Indexed: 01/02/2023] Open
Abstract
Low-dose computed tomography (CT) is desirable for treatment planning and simulation in radiation therapy. Multiple rescanning and replanning during the treatment course with a smaller amount of dose than a single conventional full-dose CT simulation is a crucial step in adaptive radiation therapy. We developed a machine learning-based method to improve image quality of low-dose CT for radiation therapy treatment simulation. We used a residual block concept and a self-attention strategy with a cycle-consistent adversarial network framework. A fully convolution neural network with residual blocks and attention gates (AGs) was used in the generator to enable end-to-end transformation. We have collected CT images from 30 patients treated with frameless brain stereotactic radiosurgery (SRS) for this study. These full-dose images were used to generate projection data, which were then added with noise to simulate the low-mAs scanning scenario. Low-dose CT images were reconstructed from this noise-contaminated projection data and were fed into our network along with the original full-dose CT images for training. The performance of our network was evaluated by quantitatively comparing the high-quality CT images generated by our method with the original full-dose images. When mAs is reduced to 0.5% of the original CT scan, the mean square error of the CT images obtained by our method is ∼ 1.6 % , with respect to the original full-dose images. The proposed method successfully improved the noise, contract-to-noise ratio, and nonuniformity level to be close to those of full-dose CT images and outperforms a state-of-the-art iterative reconstruction method. Dosimetric studies show that the average differences of dose-volume histogram metrics are < 0.1 Gy ( p > 0.05 ). These quantitative results strongly indicate that the denoised low-dose CT images using our method maintains image accuracy and quality and are accurate enough for dose calculation in current CT simulation of brain SRS treatment. We also demonstrate the great potential for low-dose CT in the process of simulation and treatment planning.
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Affiliation(s)
- Tonghe Wang
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Yang Lei
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Zhen Tian
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Xue Dong
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Yingzi Liu
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Xiaojun Jiang
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Walter J. Curran
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Tian Liu
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Hui-Kuo Shu
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
| | - Xiaofeng Yang
- Emory University, Winship Cancer Institute, Department of Radiation Oncology, Atlanta, Georgia, United States
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Panzer S, Ketterl S, Bicker R, Schoske S, Nerlich AG. How to CT scan human mummies: Theoretical considerations and examples of use. INTERNATIONAL JOURNAL OF PALEOPATHOLOGY 2019; 26:122-134. [PMID: 31362163 DOI: 10.1016/j.ijpp.2019.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 06/26/2019] [Accepted: 06/27/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE The purpose of this study was to develop and provide recommendations for computed tomography (CT) examinations of human mummies. MATERIALS AND METHODS Based on theoretical considerations and examples, recommendations for use are provided for scanning and image reconstruction parameters. Four examples are presented to illustrate the effect of different CT parameters on image quality. RESULTS The use of appropriate scanning parameters (detector collimation, pitch factor, rotation time) is known to improve image quality; technical considerations favor using lower tube voltage and higher tube current values for the purposes of scanning of human mummies. The use of appropriate image reconstruction parameters (slice thickness, increment, field of view, reconstruction filters) are the basis for individual reconstructions for the purpose of evaluation, documentation, illustration and data storage. CONCLUSIONS Downsizing the field of view to the region of interest as done in the clinical radiological routine represents one major tool to improve image quality. SIGNIFICANCE The provided recommendations should improve CT image quality in mummy studies as well as the handling of image data for reconstructions and storage. LIMITATIONS The recommendations for CT scanning parameters and image reconstructions were written with relatively new generation CT scanners in mind. Only a few examples of use were chosen and image quality assessment was performed subjectively and not by quantitative measurements.
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Affiliation(s)
- Stephanie Panzer
- Department of Radiology, Trauma Center Murnau, Prof-Küntscher-Strasse 8, D-82418 Murnau, Germany; Institute of Biomechanics, Trauma Center Murnau and Paracelsus Medical University, Salzburg, Austria, Prof-Küntscher-Strasse 8, D-82418 Murnau, Germany.
| | - Sieglinde Ketterl
- Siemens Healthcare GmbH, Europe, Middle East & Africa, Central Western Europe, Otto-Hahn-Ring 6, D-81739 Munich, Germany.
| | - Roxane Bicker
- State Museum of Egyptian Art, Gabelsbergerstrasse 35, D-80333 Munich, Germany.
| | - Sylvia Schoske
- State Museum of Egyptian Art, Gabelsbergerstrasse 35, D-80333 Munich, Germany.
| | - Andreas G Nerlich
- Institute of Pathology, Academic Clinics München-Bogenhausen and München-Schwabing Englschalkingerstrasse 77, D-81925 Munich, Germany.
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Low-dose CT angiography using ASiR-V for potential living renal donors: a prospective analysis of image quality and diagnostic accuracy. Eur Radiol 2019; 30:798-805. [DOI: 10.1007/s00330-019-06423-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/31/2019] [Accepted: 08/12/2019] [Indexed: 12/20/2022]
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Rezaee M, Letourneau D. Assessment of Image Quality and Dosimetric Performance of CT Simulators. J Med Imaging Radiat Sci 2019; 50:297-307. [PMID: 31176438 DOI: 10.1016/j.jmir.2019.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/09/2019] [Accepted: 01/17/2019] [Indexed: 11/18/2022]
Abstract
BACKGROUND CT simulator for radiation therapy aims to produce high-quality images for dose calculation and delineation of target and organs at risk in the process of treatment planning. Selection of CT imaging protocols that achieve a desired image quality while minimizing patient dose depends on technical CT parameters and their relationship with image quality and radiation dose. For similar imaging protocols using comparable technical CT parameters, there are also variations in image quality metrics between different CT simulator models. Understanding the relationship and variation is important for selecting appropriate imaging protocol and standardizing QC process. Here, we proposed an automated method to determine the relationship between image quality and radiation dose for various CT technical parameters. MATERIAL AND METHOD The impact of scan parameters on various aspects of image quality and volumetric CT dose index for a Philips Brilliance Big Bore and a Toshiba Aquilion One CT scanners were determined by using commercial phantom and automated image quality analysis software and cylindrical radiation dose phantom. RESULTS AND DISCUSSION Both scanners had very similar and satisfactory performance based on the diagnostic acceptance criteria recommended by ACR, International Atomic Energy Agency, and American Association of Physicists in Medicine. However, our results showed a compromise between different image quality components such as low-contrast and spatial resolution with the change of scanning parameters and revealed variations between the two scanners on their image quality performance. Measurement using a generic phantom and analysis by automated software was unbiased and efficient. CONCLUSION This method provides information that can be used as a baseline for CT scanner image quality and dosimetric QC for different CT scanner models in a given institution or across sites.
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Affiliation(s)
- Mohammad Rezaee
- Department of Medical Physics, Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
| | - Daniel Letourneau
- Department of Medical Physics, Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada; Department of Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Canada
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Smith P, Blackmore CC, Sicuro P. An Institutional CT Radiation Dose Reduction Quality Improvement Project. J Am Coll Radiol 2019; 16:1577-1581. [PMID: 31125542 DOI: 10.1016/j.jacr.2019.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/05/2019] [Accepted: 04/30/2019] [Indexed: 10/26/2022]
Affiliation(s)
- Philip Smith
- Virginia Mason Medical Center, Seattle, Washington
| | | | - Paul Sicuro
- Virginia Mason Medical Center, Seattle, Washington
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Tan D, Mohamad NA, Wong YH, Yeong CH, Cheah PL, Sulaiman N, Abdullah BJJ, Fabell MK, Lim KS. Experimental assessment on feasibility of computed tomography-based thermometry for radiofrequency ablation on tissue equivalent polyacrylamide phantom. Int J Hyperthermia 2019; 36:554-561. [DOI: 10.1080/02656736.2019.1610800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Daryl Tan
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Nurul Ashikin Mohamad
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Yin How Wong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Chai Hong Yeong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Peng Loon Cheah
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Norshazriman Sulaiman
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Basri Johan Jeet Abdullah
- School of Medicine, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya, Selangor, Malaysia
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mohd Kamil Fabell
- Department of Biomedical Imaging, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok Sing Lim
- Photonics Research Centre, University of Malaya, Kuala Lumpur, Malaysia
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