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 ◽  
...  

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.

2012 ◽  
Vol 27 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Darka Hadnadjev ◽  
Danijela Arandjic ◽  
Sanja Stojanovic ◽  
Olivera Ciraj-Bjelac ◽  
Predrag Bozovic ◽  
...  

This paper presents an estimation of local diagnostic reference levels in computed tomography in a large teaching hospital. Local diagnostic reference levels, expressed in terms of volume weighted computed tomography dose index and dose-length product, were estimated for three most frequent adult computer tomography examinations: head, abdomen and pelvis combined, and thorax. The established local diagnostic reference levels values were similar or slightly higher compared to the available guidelines, indicating the possibility for optimization of current practice. Analyzing the protocols used here and recently published studies on dose reduction in computed tomography, a dose-reduction technique, was proposed to decrease tube current values in all three examinations. However, the optimization should be restricted only to standard-sized patients.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257294
Author(s):  
Xiaoyan Hu ◽  
Jie Gou ◽  
Wei Lin ◽  
Chunhua Zou ◽  
Wenbo Li

Rationale and objectives This study aimed to compare the volume computed tomography dose index (CTDIvol), dose length product (DLP), and size-specific dose estimate (SSDE), with the China and updated 2017 American College of Radiology (ACR) diagnostic reference levels (DRLs) in chest CT examinations of adults based on the water-equivalent diameter (Dw). Materials and methods All chest CT examinations conducted without contrast administration from January 2020 to July 2020 were retrospectively included in this study. The Dw and SSDE of all examinations were calculated automatically by “teamplay”. The CTDIvol and DLP were displayed on the DICOM-structured dose report in the console based on a 32cm phantom.The differences in patient CTDIvol, DLP, and SSDE values between groups were examined by the one-way ANOVA. The differences in patient CTDIvol, DLP, and SSDE values between the updated 2017 ACR and the China DRLs were examined with one sample t-tests. Results In total 14666 chest examinations were conducted in our study. Patients were divided into four groups based on Dw:270 (1.84%) in 15–20 cm group, 10287 (70.14%) in the 21–25 cm group, 4097 (27.94%) in the 26–30 cm group, and 12 (0.08%) patients had sizes larger than 30 cm. CTDIvol, DLP, and SSDE increased as a function of Dw (p<0.05). CTDIvol was smaller than SSDE among groups (p<0.05). The mean CTDIvol and DLP values were lower than the 25th, 50th, and 75th percentile of the China DRLs (p <0.05). The CTDIvol, DLP, and SSDE were lower than the 50th and 75th percentiles of the updated 2017 ACR DRLs (p <0.05) among groups. Conclusions SSDE takes into account the influence of the scanning parameters, patient size, and X-ray attenuation on the radiation dose, which can give a more realistic estimate of radiation exposure dose for patients undergoing CT examinations. Establishing hospital’s own DRL according to CTDIvol and SSDE is very important even though the radiation dose is lower than the national DRLs.


2012 ◽  
Vol 4 (2) ◽  
pp. 24 ◽  
Author(s):  
Juraj Artner ◽  
Friederike Lattig ◽  
Heiko Reichel ◽  
Balkan Cakir

Despite the good general patient acceptance, high patient comfort, safety and precision in the needle placement, exposure to radiation in computed tomography (CT)- guided spinal interventions remains a serious concern, and is often used to argue against its use. The aim of this study was to determine the technical possibilities of reducing the radiation dose in CT-guided epidural and periradicular injections in lumbar spine. We evaluated the possibilities of reducing radiation dose to the patient and operator during CT-guided injections on the lumbar spine using the following steps: significant reduction of the tube current and energy used for the topogram-acquisition, narrowing the area of interest in spiral CTmode and reduction of tube current and radiation energy in the final intervention mode. Fifty-three CT-guided spinal injections were performed in the lumbar spine (34 epidural lumbar, 19 lumbar periradicular) using a low-dose protocol in non-obese patients and compared with 1870 CT-guided injections from the year 2010, when a standard dose protocol was used. Technical considerations on radiation dose reduction were provided. An average dose reduction of 85% was achieved using the low-dose protocol in CTguided epidural and periradicular injections in lumbar spine without showing any effect on safety or precision.


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