ESTIMATION OF RADIATION DOSE IN CT VENOGRAPHY OF THE LOWER EXTREMITIES: PHANTOM EXPERIMENTS USING DIFFERENT AUTOMATIC EXPOSURE CONTROL SETTINGS AND SCAN RANGES

2019 ◽  
Vol 188 (1) ◽  
pp. 109-116
Author(s):  
Yusuke Inoue ◽  
Hiroyasu Itoh ◽  
Kazunori Nagahara ◽  
Yuka Takahashi
Keyword(s):  
Radiation Dose ◽  
Effective Dose ◽  
Lower Extremities ◽  
Whole Body ◽  
Exposure Control ◽  
Automatic Exposure Control ◽  
Dose Length Product ◽  
Ct Venography ◽  
Tube Current ◽  
Phantom Experiments

Abstract We performed phantom experiments to assess radiation dose in computed tomography (CT) venography of the lower extremities. CT images of a whole-body phantom were acquired using different automatic exposure control settings and scan ranges, simulating CT venography. Tube current decreased in the lower extremities compared to the trunk. The scout direction and dose modulation strength affected tube current, dose length product (DLP) and effective dose. The middle and distal portions of the lower extremities contributed substantially to DLP but not to effective dose. When effective dose was estimated by multiplying DLP by a single conversion factor, overestimation was evident; this became more pronounced as the scan range narrowed. In CT venography of the lower extremities, the scout direction and modulation strength affect radiation dose. Use of DLP severely overestimates radiation dose and underestimates effects of scan range narrowing.

Conversion from dose-length product to effective dose in computed tomography venography of the lower extremities

2022 ◽  
Author(s):  
Yusuke Inoue ◽  
Yuka Yonekura ◽  
Kazunori Nagahara ◽  
Ayuka Uehara ◽  
Hideki Ikuma
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Conversion Factor ◽  
Lower Extremities ◽  
Pulmonary Angiography ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Venography ◽  
Simplified Method ◽  
Imaging Conditions

Abstract For radiation dose assessement of computed tomography (CT), effective dose (ED) is often estimated by multiplying the dose-length product (DLP), provided automatically by the CT scanner, by a conversion factor. We investigated such conversion in CT venography of the lower extremities performed in conjunction with CT pulmonary angiography. The study subjects consisted of eight groups imaged using different scanners and different imaging conditions (five and three groups for the GE and Siemens scanners, respectively). Each group included 10 men and 10 women. The scan range was divided into four anatomical regions (trunk, proximal thigh, knee and distal leg), and DLP was calculated for each region (regional DLP). Regional DLP was multiplied by a conversion factor for the respective region, to convert it to ED. The sum of the ED values for the four regions was obtained as standard ED. Additionally, the sum of the four regional DLP values, an approximate of the scanner-derived DLP, was multiplied by the conversion factor for the trunk (0.015 mSv/mGy/cm), as a simplified method to obtain ED. When using the simplified method, ED was overestimated by 32.3%−70.2% and 56.5%−66.2% for the GE and Siemens scanners, respectively. The degree of overestimation was positively and closely correlated with the contribution of the middle and distal portions of the lower extremities to total radiation exposure. ED/DLP averaged within each group, corresponding to the conversion factor, was 0.0089−0.0114 and 0.0091−0.0096 mSv/mGy/cm for the GE and Siemens scanners, respectively. In CT venography of the lower extremities, ED is greatly overestimated by multiplying the scanner-derived DLP by the conversion factor for the trunk. The degree of overestimation varies widely depending on the imaging conditions. It is recommended to divide the scan range and calculate ED as a sum of regional ED values.

scholarly journals Assessment of the Radiation Dose during 16 Slices CT Examinations

2019 ◽  
Vol 8 (4) ◽  
pp. 4652-4657
Keyword(s):  
Experimental Study ◽  
Monte Carlo ◽  
Radiation Dose ◽  
Effective Dose ◽  
Clinical Applications ◽  
Clinical Protocols ◽  
Dose Length Product ◽  
Conversion Factors ◽  
Current Tube ◽  
Tube Current

In this work. Two studies were presented. The first one is an experimental study of the influence of different scan parameters (potential tube. current tube and pitch) on the radiation dose is presented. It has been demonstrated that the radiation dose increases if we increase the tube current or the potential current. Contrary to the pitch. the radiation dose is reduced when the pitch increases. The second study is a Monte Carlo validation of a CT named SOMATION emotion from Siemens using GATE. Results were carried out for different voltage 80.110.130 kVp. Results of the simulation are presented and good agreements are observed (less than 2.6% for head phantom. and less than 4.6% for body phantom for all applied voltages). The influence of changing the phantom diameter on the CTDIw was also presented. the CTDIw decreased nonlinearly with increasing the phantom diameter. Moreover. the CTDIw differences decreased if the phantom diameter increased. It was demonstrated that the CTDI100 values can be characterized as functions of the kVp. mAs and diameter of phantoms. Based on these results. it is possible to optimize the CT parameters in clinical applications. Finally the effective dose was calculated using the method dose length product and the conversion factors for four clinical protocols.

scholarly journals Noise Citra dan Estimasi Dosis Radiasi dengan Aktifasi Sistem Automatic Exposure Control pada Pemeriksaan Computed Tomography Kepala

2015 ◽  
Vol 1 (2) ◽  
pp. 59-64
Author(s):  
Rini Indrati ◽  
Azlan Yazid ◽  
Bagus Abimanyu
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Activation Parameters ◽  
P Value ◽  
Exposure Control ◽  
Automatic Exposure Control ◽  
Dose Estimation ◽  
Ct Number ◽  
Tube Current ◽  
Head Computed Tomography

Background: Of the ways to maintain optimum image quality and reduce the intensity of radiation to patients is optimizing the value of tube current (mAs) using parameter of Automatic Exposure Control (AEC) or mA modulation. But at the fact in hospital, protocol parameter Automatic Exposure Control (AEC) is not activated or OFF on head computed tomography examination.Methods: This study was a quatitative experimental study. Subject of this study was head phantom. Phantom scanned with four treatments, the activation parameters was sure exp.3D-high quality, sure exp.3D-standard, sure exp.3D-low dose and AEC-OFF. Noise was analyzed using the standard deviation of the CT Number. The ROI of approximately 5 mm2 the intracranial area which is divided into three quadrants namely the anterior region, central region and posterior region of neck which is uniform are aof phantom.Results: The results showed significant differences when parameter automatic exposure control was activated and disabled or AEC-OFF with p value was 0.003 (0,05). Furthermore, based on the scanning results in a change of  radiation dose estimation to the highest doses value of the activation parameters of automatic exposure control and the lowest dose when parameter automatic exposure control deactivated or AEC-OFF.Conclusion: Activation parameters of automatic exposure control (sure exp. 3D) on a head CT examination image noise tends to decline and give a higher radiation dose than when parameter automatic exposure control deactivated or AEC-OFF.

scholarly journals Whole Body Low Dose Computed Tomography Using Third-Generation Dual-Source Multidetector With Spectral Shaping: Protocol Optimization and Literature Review

Dose-Response ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 155932582097313
Author(s):  
Dario Baldi ◽  
Liberatore Tramontano ◽  
Vincenzo Alfano ◽  
Bruna Punzo ◽  
Carlo Cavaliere ◽  
...  
Keyword(s):  
Effective Dose ◽  
Low Dose ◽  
Whole Body ◽  
Dose Length Product ◽  
Osteolytic Lesions ◽  
Subjective Image Quality ◽  
Ct Dose ◽  
Dual Source ◽  
Ct Dose Index ◽  
Low Dose Computed Tomography

For decades, the main imaging tool for multiple myeloma (MM) patient’s management has been the conventional skeleton survey. In 2014 international myeloma working group defined the advantages of the whole-body low dose computed tomography (WBLDCT) as a gold standard, among imaging modalities, for bone disease assessment and subsequently implemented this technique in the MM diagnostic workflow. The aim of this study is to investigate, in a group of 30 patients with a new diagnosis of MM, the radiation dose (CT dose index, dose-length product, effective dose), the subjective image quality score and osseous/extra-osseous findings rate with a modified WBLDCT protocol. Spectral shaping and third-generation dual-source multidetector CT scanner was used for the assessment of osteolytic lesions due to MM, and the dose exposure was compared with the literature findings reported until 2020. Mean radiation dose parameters were reported as follows: CT dose index 0.3 ± 0.1 mGy, Dose-Length Product 52.0 ± 22.5 mGy*cm, effective dose 0.44 ± 0.19 mSv. Subjective image quality was good/excellent in all subjects. 11/30 patients showed osteolytic lesions, with a percentage of extra-osseous findings detected in 9/30 patients. Our data confirmed the advantages of WBLDCT in the diagnosis of patients with MM, reporting an effective dose for our protocol as the lowest among previous literature findings.

scholarly journals Feasible Dose Reduction in Routine Chest Computed Tomography Maintaining Constant Image Quality Using the Last Three Scanner Generations: From Filtered Back Projection to Sinogram-affirmed Iterative Reconstruction and Impact of the Novel Fully Integrated Detector Design Minimizing Electronic Noise

2014 ◽  
Vol 4 ◽  
pp. 38 ◽  
Author(s):  
Lukas Ebner ◽  
Felix Knobloch ◽  
Adrian Huber ◽  
Julia Landau ◽  
Daniel Ott ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Radiation Dose ◽  
Dose Reduction ◽  
Integrated Circuit ◽  
Chest Ct ◽  
Back Projection ◽  
Dose Length Product ◽  
Chest Computed Tomography ◽  
Tube Current

Objective: The aim of the present study was to evaluate a dose reduction in contrast-enhanced chest computed tomography (CT) by comparing the three latest generations of Siemens CT scanners used in clinical practice. We analyzed the amount of radiation used with filtered back projection (FBP) and an iterative reconstruction (IR) algorithm to yield the same image quality. Furthermore, the influence on the radiation dose of the most recent integrated circuit detector (ICD; Stellar detector, Siemens Healthcare, Erlangen, Germany) was investigated. Materials and Methods: 136 Patients were included. Scan parameters were set to a thorax routine: SOMATOM Sensation 64 (FBP), SOMATOM Definition Flash (IR), and SOMATOM Definition Edge (ICD and IR). Tube current was set constantly to the reference level of 100 mA automated tube current modulation using reference milliamperes. Care kV was used on the Flash and Edge scanner, while tube potential was individually selected between 100 and 140 kVp by the medical technologists at the SOMATOM Sensation. Quality assessment was performed on soft-tissue kernel reconstruction. Dose was represented by the dose length product. Results: Dose-length product (DLP) with FBP for the average chest CT was 308 mGy*cm ± 99.6. In contrast, the DLP for the chest CT with IR algorithm was 196.8 mGy*cm ± 68.8 (P = 0.0001). Further decline in dose can be noted with IR and the ICD: DLP: 166.4 mGy*cm ± 54.5 (P = 0.033). The dose reduction compared to FBP was 36.1% with IR and 45.6% with IR/ICD. Signal-to-noise ratio (SNR) was favorable in the aorta, bone, and soft tissue for IR/ICD in combination compared to FBP (the P values ranged from 0.003 to 0.048). Overall contrast-to-noise ratio (CNR) improved with declining DLP. Conclusion: The most recent technical developments, namely IR in combination with integrated circuit detectors, can significantly lower radiation dose in chest CT examinations.

scholarly journals DIAGNOSTIC IMAGING AND IONIZING RADIATION EXPOSURE IN A LEVEL 1 TRAUMA CENTRE POPULATION MET WITH TRAUMA TEAM ACTIVATION: A ONE-YEAR PATIENT RECORD AUDIT

2020 ◽  
Vol 189 (1) ◽  
pp. 35-47
Author(s):  
Anna Bågenholm ◽  
Pål Løvhaugen ◽  
Rune Sundset ◽  
Tor Ingebrigtsen
Keyword(s):  
Diagnostic Imaging ◽  
Radiation Exposure ◽  
Effective Dose ◽  
Trauma Team ◽  
Trauma Centre ◽  
Whole Body ◽  
Reference Level ◽  
Dose Length Product ◽  
Trauma Team Activation ◽  
X Ray

Abstract This audit describes ionizing and non-ionizing diagnostic imaging at a regional trauma centre. All 144 patients (males 79.2%, median age 31 years) met with trauma team activation from 1 January 2015 to 31 December 2015 were included. We used data from electronic health records to identify all diagnostic imaging and report radiation exposure as dose area product (DAP) for conventional radiography (X-ray) and dose length product (DLP) and effective dose for CT. During hospitalization, 134 (93.1%) underwent X-ray, 122 (84.7%) CT, 92 (63.9%) focused assessment with sonography for trauma (FAST), 14 (9.7%) ultrasound (FAST excluded) and 32 (22.2%) magnetic resonance imaging. One hundred and sixteen (80.5%) underwent CT examinations during trauma admissions, and 73 of 144 (50.7%) standardized whole body CT (SWBCT). DAP values were below national reference levels. Median DLP and effective dose were 2396 mGycm and 20.42 mSv for all CT examinations, and 2461 mGycm (national diagnostic reference level 2400) and 22.29 mSv for a SWBCT.

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