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Happonen E, Husso M, Matikka H. Effect of MOSFET dosimeters' calibration method on calibration factors and radiation doses measured with the dosimeters in radiology. Biomed Phys Eng Express 2022; 8. [PMID: 35354122 DOI: 10.1088/2057-1976/ac6292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/30/2022] [Indexed: 11/11/2022]
Abstract
MOSFET dosimeters have widely been used to measure radiation doses caused by x-rays. When using the MOSFET dosimeters, calibration factors (CFs) have a direct effect on reliability of dose measurements. The aim of this paper was to study the effect of various calibration methods on the CFs of the MOSFET dosimeters. The CFs were measured on clinical digital x-ray angiography (XA) and computed tomography (CT) devices using a calibrated CT ionization chamber and a standard polymethyl methacrylate (PMMA) phantom. The measurements were conducted by having the dosimeters (1) in air, (2) on the surface of the PMMA phantom and (3) inside the phantom. A statistically significant difference was seen between the CFs measured on the XA and CT devices. The CFs measured on the CT device were 20%-165% higher than those measured with the XA device (p < 0.001) in every calibration geometry. Furthermore, the calibration geometry had a notable effect on the CFs on CT. The CFs on the surface of the phantom were 18%-25% higher than in air (p < 0.05), and the CFs inside the phantom were 32%-39% smaller than in air (p < 0.05). These results suggest that the calibration of the MOSFET dosimeters should be conducted with the same device that is used in actual dose measurements. Also, the scattering conditions and the calibration geometry should be similar in the calibration and subsequent dose measurements.
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Affiliation(s)
- Emilia Happonen
- Department of Applied Physics, University of Eastern Finland, 70210 Kuopio, Finland
| | - Minna Husso
- Diagnostic Imaging Center, Kuopio University Hospital, 70210 Kuopio, Finland
| | - Hanna Matikka
- Diagnostic Imaging Center, Kuopio University Hospital, 70210 Kuopio, Finland
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Funama Y, Oda S, Kidoh M, Sakabe D, Nakaura T. Effect of image quality on myocardial extracellular volume quantification using cardiac computed tomography: a phantom study. Acta Radiol 2022; 63:159-165. [PMID: 33461303 DOI: 10.1177/0284185120986938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND The image quality directly affects the accuracy of computed tomography (CT) extracellular volume (ECV) quantification. PURPOSE To investigate the effects of image quality and acquisition protocol on the accuracy of ECV quantification. MATERIAL AND METHODS One-volume scans were performed on a 320-row multidetector CT volume scanner using a multi-energy CT phantom. To simulate the blood pool and myocardium, solid rods representing blood and soft tissue were used in precontrast CT. Moreover, the solid rods including different iodine concentrations were used in postcontrast CT. The tube voltage was set at 120 kVp, and the tube current was changed from 750 mA (100% dose) to 190 mA (25% dose). All images underwent full- and half-scan reconstructions based on model-based iterative reconstruction. The ECV was calculated from the CT numbers between pre- and postcontrast. RESULTS The mean ECV with full- and half-scan reconstructions at the central portion was 0.275 at 100% scan dose to 0.271 at 25% scan dose and 0.276 at 100% scan dose to 0.269 at 25% scan dose. Compared with that in the 100% scan dose, the variation in each ECV increased with decreasing radiation dose. The ECV at the center of the image along the z-axis had lower variation than that at outer portion of the images. On the reconstruction algorithm, there was no statistical difference in ECVs with full- and half-scan reconstructions. CONCLUSION For stable ECV quantifications, excessive radiation dose reduction may be inappropriate, and it is better to consider the variations in ECV values depending on the slice location.
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Affiliation(s)
- Yoshinori Funama
- Department of Medical Radiation Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Seitaro Oda
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masafumi Kidoh
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Daisuke Sakabe
- Department of Radiology, Kumamoto University Hospital, Kumamoto, Japan
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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Tay ZW, Chandrasekharan P, Zhou XY, Yu E, Zheng B, Conolly S. In vivo tracking and quantification of inhaled aerosol using magnetic particle imaging towards inhaled therapeutic monitoring. Theranostics 2018; 8:3676-3687. [PMID: 30026874 PMCID: PMC6037024 DOI: 10.7150/thno.26608] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/15/2018] [Indexed: 12/14/2022] Open
Abstract
Pulmonary delivery of therapeutics is attractive due to rapid absorption and non-invasiveness but it is challenging to monitor and quantify the delivered aerosol or powder. Currently, single-photon emission computed tomography (SPECT) is used but requires inhalation of radioactive labels that typically have to be synthesized and attached by hot chemistry techniques just prior to every scan. Methods: In this work, we demonstrate that superparamagnetic iron oxide nanoparticles (SPIONs) can be used to label and track aerosols in vivo with high sensitivity using an emerging medical imaging technique known as magnetic particle imaging (MPI). We perform proof-of-concept experiments with SPIONs for various lung applications such as evaluation of efficiency and uniformity of aerosol delivery, tracking of the initial aerosolized therapeutic deposition in vivo, and finally, sensitive visualization of the entire mucociliary clearance pathway from the lung up to the epiglottis and down the gastrointestinal tract to be excreted. Results: Imaging of SPIONs in the lung has previously been limited by difficulty of lung imaging with magnetic resonance imaging (MRI). In our results, MPI enabled SPION lung imaging with high sensitivity, and a key implication is the potential combination with magnetic actuation or hyperthermia for MPI-guided therapy in the lung with SPIONs. Conclusion: This work shows how magnetic particle imaging can be enabling for new imaging and therapeutic applications of SPIONs in the lung.
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Affiliation(s)
- Zhi Wei Tay
- Department of Bioengineering, University of California, Berkeley, CA 94720, United States
| | | | - Xinyi Yedda Zhou
- Department of Bioengineering, University of California, Berkeley, CA 94720, United States
| | - Elaine Yu
- Magnetic Insight, Inc., Alameda, CA 94501, United States
| | - Bo Zheng
- Department of Bioengineering, University of California, Berkeley, CA 94720, United States
| | - Steven Conolly
- Department of Bioengineering, University of California, Berkeley, CA 94720, United States
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, United States
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Nazli SB, Aghamiri SMR, Gholizadeh Sendani N, Shams Akhtari A. EVALUATION OF RADIATION ABSORBED DOSE AND IMAGE QUALITY IN DIFFERENT RETROSPECTIVE-ECG GATING ACQUISITION METHODS OF CARDIAC CT ANGIOGRAPHY. RADIATION PROTECTION DOSIMETRY 2018; 178:304-309. [PMID: 28981808 DOI: 10.1093/rpd/ncx111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/28/2017] [Indexed: 06/07/2023]
Abstract
Cardiac computed tomography angiography (CCTA) studies have risen concern of radiobiological effects over the patients. Therefore, estimating radiation doses absorbed during CCTA is important. In this study, we compared radiation dose and image quality by using three different retrospective electrocardiography (ECG) protocols. A total of 123 patients undergoing CCTA were divided in three different groups. We used full-dose modulation (CareDose4D) technique in group (1); fixed tube current 200 mAs for group (2); and in group (3), chest circumference was used to adapt tube current (180-200 mAs) and tube potential (100-120 kVp). For groups (1) and (2), tube potential adapted depends on body mass index (BMI) in which it was 100 kVp for BMI < 27 kg/m2, and 120 kVp for BMI ≥ 27 kg/m2. Quantitive assessment of image quality was calculated by measuring signal intensity (SI) and image noise (IN) in the proximal segments of aorta root on left and right coronary arteries. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also calculated by using SI and IN. Two experienced radiologists using a 4-point scale assessed the subjective image quality. Our results show that in group (1), the mean effective dose was 4.46 mSv (range: 1.75-8.6 mSv) and for group (2), the mean effective radiation dose was 5.07 mSv (range: 2.57-9.74 mSv) and in group (3), the mean effective dose was 5.85 mSv (range: 3.36-12.17 mSv). Group (1) representing 12% and 23% decrease in radiation dose comparing by groups (2) and (3). In multivariate analysis, adjusting for BMI, radiation dose for patients with BMI < 27 kg/m2 was significantly different; 2.53 mSv for group (1) compared to 3.54 mSv in group (2) and 5.207 in group (3) (p < 0.0001). In addition, lowering tube potential from 120 to 100 kVp in 200 mAs fixed tube current, represents 27% decrease in radiation dose. The quantitative image quality (IN, SI, SNR and CNR) was not statistically significant among the groups. To sum up, Retrospective-ECG gating may reduce radiation dose by using automatic tube current modulation and 100kVp tube potential with preservation of image quality in patient's whose BMI < 27 kg/m2.
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Affiliation(s)
| | | | | | - Amin Shams Akhtari
- Department of Emergency Medicine, Faculty of Medical Science, Shahid Beheshti Medical University, Tehran, Iran
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Trattner S, Prinsen P, Wiegert J, Gerland EL, Shefer E, Morton T, Thompson CM, Yagil Y, Cheng B, Jambawalikar S, Al-Senan R, Amurao M, Halliburton SS, Einstein AJ. Calibration and error analysis of metal-oxide-semiconductor field-effect transistor dosimeters for computed tomography radiation dosimetry. Med Phys 2017; 44:6589-6602. [PMID: 28940306 DOI: 10.1002/mp.12592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 08/16/2017] [Accepted: 09/08/2017] [Indexed: 11/06/2022] Open
Abstract
PURPOSE Metal-oxide-semiconductor field-effect transistors (MOSFETs) serve as a helpful tool for organ radiation dosimetry and their use has grown in computed tomography (CT). While different approaches have been used for MOSFET calibration, those using the commonly available 100 mm pencil ionization chamber have not incorporated measurements performed throughout its length, and moreover, no previous work has rigorously evaluated the multiple sources of error involved in MOSFET calibration. In this paper, we propose a new MOSFET calibration approach to translate MOSFET voltage measurements into absorbed dose from CT, based on serial measurements performed throughout the length of a 100-mm ionization chamber, and perform an analysis of the errors of MOSFET voltage measurements and four sources of error in calibration. METHODS MOSFET calibration was performed at two sites, to determine single calibration factors for tube potentials of 80, 100, and 120 kVp, using a 100-mm-long pencil ion chamber and a cylindrical computed tomography dose index (CTDI) phantom of 32 cm diameter. The dose profile along the 100-mm ion chamber axis was sampled in 5 mm intervals by nine MOSFETs in the nine holes of the CTDI phantom. Variance of the absorbed dose was modeled as a sum of the MOSFET voltage measurement variance and the calibration factor variance, the latter being comprised of three main subcomponents: ionization chamber reading variance, MOSFET-to-MOSFET variation and a contribution related to the fact that the average calibration factor of a few MOSFETs was used as an estimate for the average value of all MOSFETs. MOSFET voltage measurement error was estimated based on sets of repeated measurements. The calibration factor overall voltage measurement error was calculated from the above analysis. RESULTS Calibration factors determined were close to those reported in the literature and by the manufacturer (~3 mV/mGy), ranging from 2.87 to 3.13 mV/mGy. The error σV of a MOSFET voltage measurement was shown to be proportional to the square root of the voltage V: σV=cV where c = 0.11 mV. A main contributor to the error in the calibration factor was the ionization chamber reading error with 5% error. The usage of a single calibration factor for all MOSFETs introduced an additional error of about 5-7%, depending on the number of MOSFETs that were used to determine the single calibration factor. The expected overall error in a high-dose region (~30 mGy) was estimated to be about 8%, compared to 6% when an individual MOSFET calibration was performed. For a low-dose region (~3 mGy), these values were 13% and 12%. CONCLUSIONS A MOSFET calibration method was developed using a 100-mm pencil ion chamber and a CTDI phantom, accompanied by an absorbed dose error analysis reflecting multiple sources of measurement error. When using a single calibration factor, per tube potential, for different MOSFETs, only a small error was introduced into absorbed dose determinations, thus supporting the use of a single calibration factor for experiments involving many MOSFETs, such as those required to accurately estimate radiation effective dose.
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Affiliation(s)
- Sigal Trattner
- Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, 10032, USA
| | - Peter Prinsen
- Philips Research, Eindhoven, 5656AE, The Netherlands
| | - Jens Wiegert
- Philips Research, Eindhoven, 5656AE, The Netherlands
| | | | | | - Tom Morton
- Philips Healthcare, Cleveland, OH, 44143, USA
| | - Carla M Thompson
- Division of Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH, USA.,Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, 44195, USA
| | - Yoad Yagil
- Philips Healthcare, Haifa, 31004, Israel
| | - Bin Cheng
- Department of Biostatistics, Columbia University Mailman School of Public Health, New York, NY, 10032, USA
| | - Sachin Jambawalikar
- Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, 10032, USA
| | - Rani Al-Senan
- Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, 10032, USA
| | - Maxwell Amurao
- Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, 10032, USA
| | - Sandra S Halliburton
- Philips Healthcare, Cleveland, OH, 44143, USA.,Division of Radiology, Imaging Institute, Cleveland Clinic, Cleveland, OH, USA.,Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.,Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, OH, 44195, USA
| | - Andrew J Einstein
- Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, 10032, USA.,Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, 10032, USA
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Funama Y, Utsunomiya D, Hirata K, Taguchi K, Nakaura T, Oda S, Kidoh M, Yuki H, Yamashita Y. Improved Estimation of Coronary Plaque and Luminal Attenuation Using a Vendor-specific Model-based Iterative Reconstruction Algorithm in Contrast-enhanced CT Coronary Angiography. Acad Radiol 2017; 24:1070-1078. [PMID: 28396126 DOI: 10.1016/j.acra.2017.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/25/2017] [Accepted: 02/28/2017] [Indexed: 01/16/2023]
Abstract
RATIONALE AND OBJECTIVES To investigate the stabilities of plaque attenuation and coronary lumen for different plaque types, stenotic degrees, lumen densities, and reconstruction methods using coronary vessel phantoms and the visualization of coronary plaques in clinical patients through coronary computed tomography (CT) angiography. MATERIALS AND METHODS We performed 320-detector volume scanning of vessel tubes with stenosis and a tube without stenosis using three types of plaque CT numbers. The stenotic degrees were 50% and 75%. Images were reconstructed with filtered back projection (FBP) and two types of iterative reconstructions (AIDR3D and FIRST [forward-projected model-based iterative reconstruction solution]), with stenotic CT number of approximately 40, 80, and 150 HU (Hounsfield unit), respectively. In each case, the tubing of the coronary vessel was filled with diluted contrast material and distilled water to reach the target lumen CT numbers of approximately 350 HU and 450 HU, and 0 HU, respectively. Peak lumen and plaque CT numbers were measured to calculate the lumen-plaque contrast. In addition, we retrospectively evaluated the image quality with regard to coronary arterial lumen and the plaque in 10 clinical patients on a 4-point scale. RESULTS At 50% stenosis, the plaque CT number with contrast enhancement increased for FBP and AIDR3D, and the difference in the plaque CT number with and without contrast enhancement was 15-44 HU for FBP and 10-31 HU for AIDR3D. However, the plaque CT number for FIRST had a smaller variation and the difference with and without contrast enhancement was -12 to 8 HU. The visual evaluation score for the vessel lumen was 2.8 ± 0.6, 3.5 ± 0.5, and 3.7 ± 0.5 for FBP, AIDR3D, and FIRST, respectively. CONCLUSIONS The FIRST method controls the increase in plaque density and the lumen-plaque contrast. Consequently, it improves the visualization of coronary plaques in coronary CT angiography.
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Affiliation(s)
- Yoshinori Funama
- Department of Medical Physics, Faculty of Life Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto 862-0976, Japan.
| | - Daisuke Utsunomiya
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kenichiro Hirata
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Katsuyuki Taguchi
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Seitaro Oda
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Masafumi Kidoh
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hideaki Yuki
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yasuyuki Yamashita
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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Armstrong I, Trevor M, Widdowfield M. Maintaining image quality and reducing dose in prospectively-triggered CT coronary angiography: A systematic review of the use of iterative reconstruction. Radiography (Lond) 2016. [DOI: 10.1016/j.radi.2015.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Organ Doses and Radiation Risk of Computed Tomographic Coronary Angiography in a Clinical Patient Population: How Do Low-Dose Acquisition Modes Compare? J Comput Assist Tomogr 2015; 39:591-7. [PMID: 26182227 DOI: 10.1097/rct.0000000000000253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE To compare the organ doses and lifetime-attributable risk of cancer for electrocardiogram-triggered sequential and high-pitch helical scanning in a clinical patient population. METHODS Phantom thermoluminiscence dosimeter measurements were used as a model for the organ dose assessment of 314 individual patients who underwent coronary computed tomographic angiography. Patient-specific lifetime-attributable cancer risks were calculated. RESULTS Phantom measurements showed that heart rate had a significant influence on the delivered radiation exposure in sequential mode, and calcium scoring and contrast bolus tracking scans make a nonnegligible contribution to patients' dose. Therefore, they should be taken into account for patients' organ dose estimations. Median cancer induction risks are low, with 0.008% (0.0016%) and 0.022% (0.056%) for high-pitch and sequential scanning for men (women), respectively. CONCLUSIONS The use of high-pitch helical scanning leads to 65% and 72% lower lifetime-attributable risk values for men and women, respectively, compared with sequential scanning.
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Behroozi H, Davoodi M, Aghasi S. Radiation Dose to the Thyroid and Gonads in Patients Undergoing Cardiac CT Angiography. IRANIAN JOURNAL OF RADIOLOGY : A QUARTERLY JOURNAL PUBLISHED BY THE IRANIAN RADIOLOGICAL SOCIETY 2015; 12:e20619. [PMID: 26060556 PMCID: PMC4457964 DOI: 10.5812/iranjradiol.20619] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/05/2014] [Accepted: 07/13/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND The present data show a global increase in the rate of cardiovascular disease. Cardiac CT angiography has developed as a fast and non-invasive cardiac imaging modality following the introduction of multi-slice computed tomogaraphy. OBJECTIVES The aim of this study was to measure the radiation dose to the thyroid and pelvis regions in patients undergoing cardiac CT angiography using the Care Dose 4D method of 64-slice scanner. PATIENTS AND METHODS Eighty-one patients (41 males and 40 females) who were diagnosed with suspected coronary artery disease and were referred to Golestan Hospital, Imaging Department were recruited. Inclusion criteria were based on the protocol of multi-slice CT coronary angiography. The radiation dose to the thyroid and pelvis regions was measured using thermo luminescent dosimeters (TLDs). RESULTS The mean radiation dose to the thyroid in male and female subjects was 0.32 mSv and 0.41 mSv, respectively (P = 0.032) (total mean, 0.36 mSv). The mean radiation dose to the pelvis in male and female subjects was 81 μSv and 112 μSv, respectively (P = 0.026) (total mean, 96.5 μSv). CONCLUSIONS The total mean radiation dose to the thyroid and gonads was 0.36 mSv, and 96.5 μSv, respectively for the subjects. These values were high for one organ in a single study. Gender can affect the radiation dose to the thyroid and gonads. This can be attributed to the anatomical characteristic differences of the male and female subjects.
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Affiliation(s)
- Hamid Behroozi
- Department of Radiologic Technology, Faculty of Paramedicine, Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad Davoodi
- Department of Radiologic Technology, Faculty of Paramedicine, Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Shahriar Aghasi
- Department of Radiologic Technology, Faculty of Paramedicine, Jundishapur University of Medical Sciences, Ahvaz, Iran
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Khan AN, Shuaib W, Nikolic B, Khan MK, Kang J, Khosa F. Absorbed radiation dose in radiosensitive organs using 64- and 320-row multidetector computed tomography: a comparative study. SCIENTIFICA 2014; 2014:305942. [PMID: 25170427 PMCID: PMC4142155 DOI: 10.1155/2014/305942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 06/16/2014] [Indexed: 06/03/2023]
Abstract
Aim. To determine absorbed radiation dose (ARD) in radiosensitive organs during prospective and full phase dose modulation using ECG-gated MDCTA scanner under 64- and 320-row detector modes. Methods. Female phantom was used to measure organ radiation dose. Five DP-3 radiation detectors were used to measure ARD to lungs, breast, and thyroid using the Aquilion ONE scanner in 64- and 320-row modes using both prospective and dose modulation in full phase acquisition. Five measurements were made using three tube voltages: 100, 120, and 135 kVp at 400 mA at heart rate (HR) of 60 and 75 bpm for each protocol. Mean acquisition was recorded in milligrays (mGy). Results. Mean ARD was less for 320-row versus 64-row mode for each imaging protocol. Prospective EKG-gated imaging protocol resulted in a statistically lower ARD using 320-row versus 64-row modes for midbreast (6.728 versus 19.687 mGy, P < 0.001), lung (6.102 versus 21.841 mGy, P < 0.001), and thyroid gland (0.208 versus 0.913 mGy; P < 0.001). Retrospective imaging using 320- versus 64-row modes showed lower ARD for midbreast (10.839 versus 43.169 mGy, P < 0.001), lung (8.848 versus 47.877 mGy, P < 0.001), and thyroid gland (0.057 versus 2.091 mGy; P < 0.001). ARD reduction was observed at lower kVp and heart rate. Conclusions. Dose reduction to radiosensitive organs is achieved using 320-row compared to 64-row modes for both prospective and retrospective gating, whereas 64-row mode is equivalent to the same model 64-row MDCT scanner.
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Affiliation(s)
- Atif N. Khan
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Waqas Shuaib
- Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA 30308, USA
| | - Boris Nikolic
- Department of Radiology, Albert Einstein Medical Center, Philadelphia, PA 19141, USA
| | - Mohammad K. Khan
- Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA 30308, USA
| | - Jian Kang
- Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA 30308, USA
| | - Faisal Khosa
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA 30308, USA
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Funama Y, Utsunomiya D, Taguchi K, Oda S, Shimonobo T, Yamashita Y. Automatic exposure control at single- and dual-heartbeat CTCA on a 320-MDCT volume scanner: Effect of heart rate, exposure phase window setting, and reconstruction algorithm. Phys Med 2014; 30:385-90. [DOI: 10.1016/j.ejmp.2013.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 10/16/2013] [Accepted: 10/22/2013] [Indexed: 12/27/2022] Open
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Khan AN, Khosa F, Nikolic B, Shuaib W, Lin PJP, Khan MK. Cancerogenesis Risks between 64 and 320 Row Detector CT for Coronary CTA Screening. J Clin Imaging Sci 2014; 4:18. [PMID: 24987565 PMCID: PMC4060400 DOI: 10.4103/2156-7514.131640] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 01/28/2014] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES This study compares cancerogenesis risks posed by the 64 row detector and the 320 row detector computed tomography scanners used during coronary computed tomography angiography (CCTA) following decennial screening guidelines. MATERIAL AND METHODS Data of the radiation absorbed after CCTA by lung, thyroid, and female breast in patients between 50 and 70 years of age obtained from prior published literature for the 64 row CT scanner were compared with data from our study using 320 row detector CT scanner. Data from the 64 row and the 320 row detector CT scanners was used to determine lifetime attributable risks (LAR) of cancer based on the biological effects of ionizing radiation (BEIR) VII report. RESULTS The relative reduction of LAR (%) for 50-, 60-, and 70-year-old patients undergoing scanning with the 320 row detector CT scanner was 30% lower for lung, and more than 50% lower for female breast when compared with results from 64 row detector CT scanner. The use of 320 row detector CT would result in a combined cumulative cancer incidence of less than 1/500 for breast in women and less than 1/1000 for lung in men; By comparison, this is much lower than other more common risk factors: 16-fold for lung cancer in persistent smokers, 2-fold for breast cancer with a first degree family member history of breast cancer, and 10-fold for thyroid cancer with a family member with thyroid cancer. Decennial screening would benefit at least 355,000 patients from sudden cardiac death each year, 94% of whom have significant coronary artery disease, with at least one stenosis >75%. LAR for thyroid cancer was negligible for both scanners. CONCLUSION Lung and female breast LAR reductions with 320 row detector compared with 64 row detector CT are substantial, and the benefits would outweigh increased cancer risks with decennial screening in the age group of 50-70 years.
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Affiliation(s)
- Atif N Khan
- Department of Radiology, BIDMC, Harvard Medical School, Boston, MA, USA
| | - Faisal Khosa
- Department of Radiology, Emory University Hospital Atlanta, GA, USA
| | - Boris Nikolic
- Department of Radiology, Albert Einstein Medical Center, Philadelphia, PA, USA
| | - Waqas Shuaib
- Department of Radiology, Emory University Hospital Atlanta, GA, USA
| | - Pei-Jan Paul Lin
- Department of Radiology, Virginia Commonwealth University, Richmond, VA, USA
| | - Mohammad K Khan
- Department of Radiology, Emory University Hospital Atlanta, GA, USA
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Khan AN, Khosa F, Shuaib W, Nasir K, Blankstein R, Clouse M. Effect of Tube Voltage (100 vs. 120 kVp) on Radiation Dose and Image Quality using Prospective Gating 320 Row Multi-detector Computed Tomography Angiography. J Clin Imaging Sci 2013; 3:62. [PMID: 24605257 PMCID: PMC3935263 DOI: 10.4103/2156-7514.124092] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 05/08/2013] [Indexed: 01/09/2023] Open
Abstract
Objectives: The objective of the following study is to evaluate the effect of reducing tube voltage from 120 to 100 kVp using prospective gating 320 row multi-detector computed tomography angiography on image quality and reduction in radiation dose. Materials and Methods: A total of 78 sequential patients were scanned with prospective electrocardiogram gating. A total of 45 patients (Group 1) with mean body mass index (BMI) 29 ± 2 and heart rate (HR) 57 ± 7 beats per minute (BPM) were scanned at 120 kVp. 33 patients (Group 2) with mean BMI 23 ± 3 and HR 58 ± 6 bpm were scanned at 100 kVp. Effective dose was calculated using dose length product and factor (k = 0.014). Quantitative assessment of image quality was calculated by measuring signal to noise ratio (SNR) and contrast to noise ratio (CNR) in the left ventricle and left main coronary artery. Two experienced cardiac radiologists using a three-point ordinal scale assessed subjectively image quality. Results: In Group 1, the median radiation dose was 5.31 mSv (95% confidence interval [CI]: 4.86-6.09) and for Group 2 (P = 0.009) the mean radiation dose was 3.71 mSv (95% CI: 2.76-4.87), representing 30% decrease in radiation dose. In multivariate analyses, adjusting for age, gender, HR, BMI, tube current and scan length, an absolute median reduction of 2.21 mSv (1.13-3.29 mSv) was noted in patients scanned with 100 kVp (P < 0.0001). The quantitative image quality (SNR and CNR) was not statistically significant between the groups. Subjective image quality was rated as good or excellent in 99% of coronary segments for both groups (P value was considered as non-significant). Conclusion: Our study suggests that radiation dose may be lowered from 120 to 100 kVp with preservation of image quality in patient's whose BMI is ≤27.
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Affiliation(s)
- Atif N Khan
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA
| | - Faisal Khosa
- Department of Radiology, Emory University Hospital Midtown, Atlanta, GA, USA
| | - Waqas Shuaib
- Department of Radiology, Emory University Hospital Midtown, Atlanta, GA, USA
| | - Khurram Nasir
- Department of Cardiology, Yale University School of Medicine, New Haven, CT, USA
| | - Ron Blankstein
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Melvin Clouse
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA
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Brady SL, Kaufman RA. Establishing a standard calibration methodology for MOSFET detectors in computed tomography dosimetry. Med Phys 2012; 39:3031-40. [DOI: 10.1118/1.4712221] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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