scholarly journals Effective Dose Levels from Computed Tomography of the Head during Contrast Studies in Nigeria

Health ◽  
2015 ◽  
Vol 07 (08) ◽  
pp. 915-919 ◽  
Author(s):  
Thomas Adejoh ◽  
Nzotta Chukwuemeka Christian ◽  
Flavious Bobuin Nkubli ◽  
Joseph Zira Dlama
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Dose Levels ◽  
Contrast Studies

scholarly journals Measurement of radiation dose in multi-slice computed tomography

2016 ◽  
Vol 9 (4) ◽  
pp. 196
Author(s):  
Surendra Maharjan ◽  
Sudil Prajapati ◽  
Om Biju Panta
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Standard Dose ◽  
Reference Dose ◽  
International Reference ◽  
Ct Dose ◽  
Abdomen Ct ◽  
Standard Patient ◽  
Effective Doses ◽  
Dose Levels

<p>The aim of this study was to measure the radiation doses for computed tomography (CT) examinations of the head, chest and abdomen in adult patients in Nepal in comparison to international standard. Dose length products (DLP) and effective doses for standard patient sizes were calculated from the reported volume CT dose index (CTDI<sub>Vol</sub>). Details were obtained from approximately 90 CT examinations carried out in 128 slice CT scan. Effective dose was calculated for each examination using CT dose indices, exposure related parameters and CTDI-to-effective dose conversion factors. The CTDI and DLP were below the established international reference dose levels for head and chest while for the abdomen and pelvis, the CTDl and DLP were above the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen were 1.7, 5.4 and 17.7 mGy respectively. In conclusion, for the routine head and chest protocol, CTDI, DLP and ED were found to be significantly lower compared to the recommendation of European Commission. However, abdomen CT scans showed higher dose values because of multiple phase scans and longer scan lengths.</p>

Using 100- instead of 120-kVp computed tomography to diagnose pulmonary embolism almost halves the radiation dose with preserved diagnostic quality

2010 ◽  
Vol 51 (3) ◽  
pp. 260-270 ◽  
Author(s):  
Peter Björkdahl ◽  
Ulf Nyman
Keyword(s):  
Computed Tomography ◽  
Pulmonary Embolism ◽  
Image Quality ◽  
Radiation Dose ◽  
Effective Dose ◽  
Ct Number ◽  
Subjective Image Quality ◽  
Diagnostic Quality ◽  
X Ray ◽  
Tube Potential

Background: Concern has been raised regarding the mounting collective radiation doses from computed tomography (CT), increasing the risk of radiation-induced cancers in exposed populations. Purpose: To compare radiation dose and image quality in a chest phantom and in patients for the diagnosis of pulmonary embolism (PE) at 100 and 120 peak kilovoltage (kVp) using 16-multichannel detector computed tomography (MDCT). Material and Methods: A 20-ml syringe containing 12 mg I/ml was scanned in a chest phantom at 100/120 kVp and 25 milliampere seconds (mAs). Consecutive patients underwent 100 kVp ( n = 50) and 120 kVp ( n = 50) 16-MDCT using a “quality reference” effective mAs of 100, 300 mg I/kg, and a 12-s injection duration. Attenuation (CT number), image noise (1 standard deviation), and contrast-to-noise ratio (CNR; fresh clot = 70 HU) of the contrast medium syringe and pulmonary arteries were evaluated on 3-mm-thick slices. Subjective image quality was assessed. Computed tomography dose index (CTDIvol) and dose–length product (DLP) were presented by the CT software, and effective dose was estimated. Results: Mean values in the chest phantom and patients changed as follows when X-ray tube potential decreased from 120 to 100 kVp: attenuation +23% and +40%, noise +38% and +48%, CNR −6% and 0%, and CTDIvol −38% and −40%, respectively. Mean DLP and effective dose in the patients decreased by 42% and 45%, respectively. Subjective image quality was excellent or adequate in 49/48 patients at 100/120 kVp. No patient with a negative CT had any thromboembolism diagnosed during 3-month follow-up. Conclusion: By reducing X-ray tube potential from 120 to 100 kVp, while keeping all other scanning parameters unchanged, the radiation dose to the patient may be almost halved without deterioration of diagnostic quality, which may be of particular benefit in young individuals.

scholarly journals Image Quality and Dose Reduction by Dual Source Computed Tomography Coronary Angiography: Protocol Comparison

Dose-Response ◽  
2018 ◽  
Vol 16 (4) ◽  
pp. 155932581880583 ◽  
Author(s):  
Ernesto Forte ◽  
Serena Monti ◽  
Chiara Anna Parente ◽  
Lukas Beyer ◽  
Roberto De Rosa ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Coronary Angiography ◽  
Effective Dose ◽  
Computed Tomography Coronary Angiography ◽  
Correct Selection ◽  
Dual Source ◽  
Group A ◽  
Noise Ratio ◽  
Dual Source Computed Tomography

Purpose: To compare image quality and radiation dose among different protocols in patients who underwent a 128-slice dual source computed tomography coronary angiography (DSCT-CTCA). Methods: Ninety patients were retrospectively grouped according to heart rate (HR): 26 patients (group A) with stable HR ≤60 bpm were acquired using high pitch spiral mode (FLASH); 48 patients (group B) with irregular HR ≤60 bpm or stable HR between 60 and 70 bpm using step and shoot mode; and 16 patients (group C) with irregular HR >60 bpm or stable HR ≥70 bpm by retrospective electrocardiogram pulsing acquisition. Signal to noise ratio (SNR) and contrast to noise ratio (CNR) were measured for the main vascular structures. Moreover, the dose-length product and the effective dose were assessed. Results: Both SNR and CNR were higher in group A compared to group C (18.27 ± 0.32 vs 11.22 ± 0.50 and 16.75 ± 0.32 vs 10.17 ± 0.50; P = .001). The effective dose was lower in groups A and B (2.09 ± 1.27 mSv and 4.60 ± 2.78 mSv, respectively) compared to group C (9.61 ± 5.95 mSv) P < .0001. Conclusion: The correct selection of a low-dose, HR-matched CTCA scan protocol with a DSCT scanner provides substantial reduction of radiation exposure and better SNR and CNR.

scholarly journals Effective Dose Estimations for Helical Computed Tomography in Lung Cancer Screening

2001 ◽  
Vol 57 (8) ◽  
pp. 939-946 ◽  
Author(s):  
HIDEAKI OKAMOTO ◽  
MASAYOSHI MIYAZAKI ◽  
AKITOSHI YONEDA ◽  
KEIICHI SUZUKI ◽  
KOUKI UEDA ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Lung Cancer ◽  
Cancer Screening ◽  
Effective Dose ◽  
Lung Cancer Screening ◽  
Helical Computed Tomography

Determination of Collective Effective Dose Equivalent due to Computed Tomography in Denmark in 1989

1992 ◽  
Vol 43 (1-4) ◽  
pp. 37-40
Author(s):  
K.A. Jessen ◽  
J.J. Christensen ◽  
J. Jørgensen ◽  
J. Petersen ◽  
E.W. Sørensen
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Effective Dose Equivalent ◽  
Dose Equivalent

Evaluation of Radiation Doses from Computed Tomography Conducted in Al Jouf Region (Saudi Arabia)

2021 ◽  
Vol 11 (8) ◽  
pp. 2130-2136
Author(s):  
Ziyad Awadh Alrowaili ◽  
M. Ashari
Keyword(s):  
Computed Tomography ◽  
Saudi Arabia ◽  
Effective Dose ◽  
Computer Software ◽  
Northern Region ◽  
The Body ◽  
Adult Patients ◽  
Dose Length Product ◽  
Comparison Of The Results ◽  
Dose Index

A safe radiation dose from computed tomography (CT) is normally specified through the Computed Tomography Dose Index (CTDI) as an “effective dose.” Radiation exposure from CT is relatively high in comparison with other radiological tests. In this paper, we evaluate doses used on adult patients during typical CT scans, in Al Jouf, the northern region of Saudi Arabia. Scanning processes were taken place in different parts of the body; including the pelvis, head, abdomen, and chest. The dose indices were calculated using the CT-expo v2.5 computer software. A comparison of the results with similar investigations, regionally and globally, was made. Other comparisons between displayed and calculated dose indices were also performed. The main values of CT volume are the dose index (CTDIvol) and dose-length product (DLP). The effectiveness results for head CTs were 45.0 mGy, 488 mGy.cm, and 5.2 mSv; while for pelvic CTs they were 16.4 mGy, 391 mGy.cm, and 4.0 mSv; whereas for abdominal CTs they were 22.2 mGy, 613 mGy.cm, and 6.5 mSv; finally they were 17.5 mGy, 380 mGy.cm, and 3.9 mSv for chest CTs. It is confirmed that the values obtained are within the internationally accepted values, except for the values of the head examination, in which the effective dose value of 5.2 mSv was higher than the recommended value. This work gives an overview of the doses received by adult patients during regular CT examination. It is the first regional CT dose survey and provides a baseline for improvement and quality control in the region of Al Jouf.

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.

Determination of Collective Effective Dose Equivalent due to Computed Tomography in Denmark in 1989

1992 ◽  
Vol 43 (1-4) ◽  
pp. 37-40 ◽  
Author(s):  
K.A. Jessen ◽  
J.J. Christensen ◽  
J. Jørgensen ◽  
J. Petersen ◽  
E.W. Sørensen
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Effective Dose Equivalent ◽  
Dose Equivalent
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