Radiation dose and image quality of double-loaded cassettes

1996 ◽  
Vol 23 (2) ◽  
pp. 239-240 ◽  
Author(s):  
Charles A. Kelsey ◽  
Fred A. Mettler ◽  
Lisa M. Sullivan
Keyword(s):  
Author(s):  
Michael Esser ◽  
Sabine Hess ◽  
Matthias Teufel ◽  
Mareen Kraus ◽  
Sven Schneeweiß ◽  
...  

Purpose To analyze possible influencing factors on radiation exposure in pediatric chest CT using different approaches for radiation dose optimization and to determine major indicators for dose development. Materials and Methods In this retrospective study at a clinic with maximum care facilities including pediatric radiology, 1695 chest CT examinations in 768 patients (median age: 10 years; range: 2 days to 17.9 years) were analyzed. Volume CT dose indices, effective dose, size-specific dose estimate, automatic dose modulation (AEC), and high-pitch protocols (pitch ≥ 3.0) were evaluated by univariate analysis. The image quality of low-dose examinations was compared to higher dose protocols by non-inferiority testing. Results Median dose-specific values annually decreased by an average of 12 %. High-pitch mode (n = 414) resulted in lower dose parameters (p < 0.001). In unenhanced CT, AEC delivered higher dose values compared to scans with fixed parameters (p < 0.001). In contrast-enhanced CT, the use of AEC yielded a significantly lower radiation dose only in patients older than 16 years (p = 0.04). In the age group 6 to 15 years, the values were higher (p < 0.001). The diagnostic image quality of low-dose scans was non-inferior to high-dose scans (2.18 vs. 2.14). Conclusion Radiation dose of chest CT was reduced without loss of image quality in the last decade. High-pitch scanning was an independent factor in this context. Dose reduction by AEC was limited and only relevant for patients over 16 years. Key Points Citation Format


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Robert Forbrig ◽  
Michael Ingrisch ◽  
Robert Stahl ◽  
Katharina Stella Winter ◽  
Maximilian Reiser ◽  
...  

Abstract In this third-generation dual-source CT (DSCT) study, we retrospectively investigated radiation dose and image quality of portal-venous high-pitch emergency CT in 60 patients (28 female, mean age 56 years) with a body mass index (BMI) ≥ 30 kg/m2. Patients were dichotomized in groups A (median BMI 31.5 kg/m2; n = 33) and B (36.8 kg/m2; n = 27). Volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose length product (DLP) and effective dose (ED) were assessed. Contrast-to-noise ratio (CNR) and dose-independent figure-of-merit (FOM) CNR were calculated. Subjective image quality was assessed using a five-point scale. Mean values of CTDIvol, SSDE as well as normalized DLP and ED were 7.6 ± 1.8 mGy, 8.0 ± 1.8 mGy, 304 ± 74 mGy * cm and 5.2 ± 1.3 mSv for group A, and 12.6 ± 3.7 mGy, 11.0 ± 2.6 mGy, 521 ± 157 mGy * cm and 8.9 ± 2.7 mSv for group B (p < 0.001). CNR of the liver and spleen as well as each calculated FOM CNR were significantly higher in group A (p < 0.001). Subjective image quality was good in both groups. In conclusion, third-generation abdominal high-pitch emergency DSCT yields good image quality in obese patients. Radiation dose increases in patients with a BMI > 36.8 kg/m2.


2020 ◽  
Vol 30 (5) ◽  
pp. 2712-2721 ◽  
Author(s):  
Waleed Abdellatif ◽  
Eric Esslinger ◽  
Kevin Kobes ◽  
Amanda Wong ◽  
Jennifer Powell ◽  
...  

2016 ◽  
Vol 2 (1) ◽  
pp. 129-133
Author(s):  
Ardi Soesilo Wibowo ◽  
Gatot Murti Wibowo ◽  
Anang Prabowo

Backgroud: Examination of the abdomen CT scan is often done by using standard protocol, meanwhile the actual parameter can be modified according to local needs considering image quality and radiation dose based on Karabulut and Ariyuek (2016). Abdomen CT Scan by GE 16 slices unit in Radiology Instaallation of Dr. Saiful Anwar Malang Hospital, using exposure factor of 120 kV, 234 mAs and the value of the CTDI dose was 53.04 mGy. While the BAPETEN’s reference of CTDI value, a CT scan of abdomen was 25 mGy.  This study aims to determine the changes of the value of kV and mAs to the image quality and the radiaton dose in the abdomen MSCT examination on abdominal tumor case in Radiology Installation of Dr. Saiful Anwar Malang Hospital.Methods: This research was a quantitative research with an experimental approach. The data were collected from three variations of tube voltage (kV) ie 100 kV, 120 kV and 140 kV and three variations of tube current value and time (mAs) ie, 180 mAs, 195 mAs, and 210 mAs. Radiographs was evaluated by three radiology physicians. Data were analyzed by scoring method of respondent’s assessment to assess MSCT image quality of abdominal tumor, while the radiation dose was obtained by CTDI recording.Results: The results showed that there was influence of tube voltage variation to image quality of abdominal tumor using MSCT unit. The higher kV used, the higher image quality resulted. From the calculation of the percentage from the assessment, the highest score of variation was at 140 kV, while the lowest score of variation was at 100 kV. Based on the recording CTDI radiation dose on the monitor, found that the higher value of kV, the higher radiation resulted. The mAs variations influenced the image quality of abdominal tumor using MSCT unit. Acoording to the percentage of the assessment, the highest score of variation found in 210 mAs, and the lowest score of variation found in 180 mAs. Based on the recording of radiation dose on the monitor, the higher mAs value, the higher radiation dose using MSCT unit. It was recommended to use 195 kV and 120 mAs for MSCT examination of abdominal tumor in Radiology Installation of Dr. Saiful Anwar Malang Hospital.Conclusion: There was influence of kV and mAs variation to anatomical image clarity and radiation dose of abdomen MSCT examination


Author(s):  
Halinda Fatmayanti ◽  
Kusworo Adi ◽  
Yeti Kartikasari

Background: Thorax MSCT examination is a diagnostic imaging that is capable of displaying both normal and pathological lung and respiratory organs. MSCT examination also has a better level of sensitivity and specificity compared to other modalities, but the radiation exposure given is very high, so the radiation dose given to patients is high. The reduction in radiation dose is very important because of the direct exposure to sensitive tissue. One method of reducing radiation dose is by reducing the tube voltage. However, the decrease in tube voltage causes a decrease in image quality as indicated by increased noise and decreased CNR. To maintain the quality of the image at low tube voltage setting, an IR reconstruction of SAFIRE was used. The purpose of this research is to know the impact of using SAFIRE on dose radiation and image quality of thorax MSCT.Methods: This study was an experimental study with a quasi-experimental study design. The object used was the N-1 Lungman chest phantom in which an artificial tumor was attached. Radiation dose assessment used CTDI value, while image quality assessment used noise and CNR. Data processing was conducted using linear regression test.Results: There was an effect of tube voltage setting and SAFIRE setting on radiation dose and image quality.Conclusions: Tube voltage ssetting and SAFIRE setting had an effect on radiation dose and image quality. Tube voltage setting and SAFIRE strength level setting that were able to provide optimal radiation dose and image quality were tube voltage of 80 kVp and SAFIRE strength levels 3 and 4 (S3 and S4). 


2018 ◽  
Vol 59 (12) ◽  
pp. 1458-1465 ◽  
Author(s):  
Stefan Haneder ◽  
Florian Siedek ◽  
Jonas Doerner ◽  
Gregor Pahn ◽  
Nils Grosse Hokamp ◽  
...  

Background A novel, multi-energy, dual-layer spectral detector computed tomography (SDCT) is commercially available now with the vendor’s claim that it yields the same or better quality of polychromatic, conventional CT images like modern single-energy CT scanners without any radiation dose penalty. Purpose To intra-individually compare the quality of conventional polychromatic CT images acquired with a dual-layer spectral detector (SDCT) and the latest generation 128-row single-energy-detector (CT128) from the same manufacturer. Material and Methods Fifty patients underwent portal-venous phase, thoracic-abdominal CT scans with the SDCT and prior CT128 imaging. The SDCT scanning protocol was adapted to yield a similar estimated dose length product (DLP) as the CT128. Patient dose optimization by automatic tube current modulation and CT image reconstruction with a state-of-the-art iterative algorithm were identical on both scanners. CT image contrast-to-noise ratio (CNR) was compared between the SDCT and CT128 in different anatomic structures. Image quality and noise were assessed independently by two readers with 5-point-Likert-scales. Volume CT dose index (CTDIvol), and DLP were recorded and normalized to 68 cm acquisition length (DLP68). Results The SDCT yielded higher mean CNR values of 30.0% ± 2.0% (26.4–32.5%) in all anatomic structures ( P < 0.001) and excellent scores for qualitative parameters surpassing the CT128 (all P < 0.0001) with substantial inter-rater agreement (κ ≥ 0.801). Despite adapted scan protocols the SDCT yielded lower values for CTDIvol (–10.1 ± 12.8%), DLP (−13.1 ± 13.9%), and DLP68 (–15.3 ± 16.9%) than the CT128 (all P < 0.0001). Conclusion The SDCT scanner yielded better CT image quality compared to the CT128 and lower radiation dose parameters.


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