scholarly journals Assessment of Imaging Protocol and Patients Radiation Exposure in Computed Tomography Colonography

2021 ◽  
Vol 11 (11) ◽  
pp. 4761
Author(s):  
Mohammed Alsufayan ◽  
Abdelmoneim Sulieman ◽  
Rayan Moslem ◽  
Abdullah Asiri ◽  
Abdullah Alomary ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Radiology Department ◽  
Imaging Protocol ◽  
Computed Tomography Colonography ◽  
Automatic Tube Current Modulation ◽  
Tube Current ◽  
Medical City ◽  
Colon And Rectum ◽  
Effective Doses

In the screening and identifying of colon and rectum malignancy, computed tomography colonography (CTC) is a highly effective imaging technique, albeit patients receiving a significant effective dose. Accordingly, patient dose evaluation is an important need, seeking to ensure benefits outweigh the projected cancer risk. Objective: For CTC procedures carried out in the Radiology Department, Medical Imaging Operation Services, King Fahad Medical City (KFMC), evaluation is done using the current American College of Radiology (ACR) imaging protocol and concomitant patient-effective doses. Study is carried out on a sample size of 55 CTC procedures, involving 25 males (45%) and 30 females (55%). The patients were classified as follows: two groups based on CT machine; four groups based on the applied protocol; and three groups based on the procedure results. All procedures were carried out using two machines, the products of two different vendors (a GE Healthcare DISCOVERY CT 750 HD 64 slices dual-energy scanner and a Philips Brilliance CT 64 slices scanner). The overall mean, standard deviation (SD), median, and range of the effective dose (in mSv) were 11.57 ± 7.75, 9.25 (2.17–31.93). Automatic tube current modulation (ATCM) shows a significant increase in CTDIvol up to 69% and effective dose (mSv) up to 95% than the manual tube current (mA) compared to the standard protocol. The CT protocol variation results in a three-fold variation in patient-effective dose. The technologist role is crucial in selecting a noise reference based on patient weight and adjusting tube current per slice to avoid overexposure during ATCM protocol.

scholarly journals Assessment of Organ and Effective Doses Received by Paediatric Patients Undergoing Computed Tomography Examinations in Three Hospitals in Brazzaville, Congo Republic: An Urgent Necessity for Regulatory Control

2021 ◽  
pp. 527-550
Author(s):  
J. Bazoma ◽  
G. B. Dallou ◽  
P. Ondo Meye ◽  
C. Bouka Biona ◽  
Saïdou ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Absorbed Dose ◽  
Regulatory Control ◽  
Ct Scans ◽  
Radiological Protection ◽  
Age Group ◽  
Organ Doses ◽  
Paediatric Patients ◽  
Effective Doses

The present study aimed at estimating organ and effective doses from computed tomography (CT) scans of paediatric patients in three hospitals in Brazzaville, Congo Republic. A total of 136 data on paediatric patients, from 0.25 (3 months) to 15 years old, who underwent head, chest, abdomen – pelvis (AP) and chest – abdomen – pelvis (CAP) CT scans was considered. The approach followed in the present study to compute organ doses was to use pre-calculated volume CT dose index (CTDIvol) – and 100 milliampere-second (mAs) – normalized organ doses determined by Monte Carlo (MC) simulation. Effective dose were then derived using the international commission on radiological protection (ICRP) publications 60 and 103 formalism. For comparison purposes, effective dose were also computed using dose-length product (DLP) – to – effective dose conversion factors. A relatively high variation in organ and effective doses was observed in each age group due to the dependence of patient dose on the practice of technicians who perform the CT scan within the same facility or from one facility to another, patient size and lack of adequate training of technicians. In the particular case of head scan, the brain and the eye lens were delivered maximum absorbed doses of 991.81 mGy and 1176.51 mGy, respectively (age group 10-15 y). The maximum absorbed dose determined for the red bone marrow was 246.08 mGy (age group 1-5 y). This is of concern as leukaemia and brain tumours are the most common childhood cancers and as the ICRP recommended absorbed dose threshold for induction of cataract is largely exceeded. Effective doses derived from MC calculations and ICRP publications 60 and 103 tissues weighting factors showed a 0.40-17.61 % difference while the difference between effective doses derived by the use of k- factors and those obtained by MC calculations ranges from 0.06 to 224.87 %. The study has shown that urgent steps should be taken in order to significantly reduce doses to paediatric patients to levels observed in countries where dose reduction techniques are successfully applied.

ABDOMEN–PELVIS COMPUTED TOMOGRAPHY PROTOCOL OPTIMIZATION: AN IMAGE QUALITY AND DOSE ASSESSMENT

2018 ◽  
Vol 184 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Nadine Helena Pelegrino Bastos Maués ◽  
Allan Felipe Fattori Alves ◽  
Ana Luiza Menegatti Pavan ◽  
Sergio Marrone Ribeiro ◽  
Seizo Yamashita ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Dose Assessment ◽  
Quality Analysis ◽  
Image Quality Analysis ◽  
Low Contrast ◽  
Automatic Tube Current Modulation ◽  
Tube Current ◽  
High Level

Abstract Computed tomography (CT) has a high level of sensitivity and specificity for the diagnosis and follow-up of pathologies of the abdomen–pelvis region. Some features, such as automatic tube current modulation (ATCM), permits the acquisition of quality images with low radiation doses. This study evaluated the image quality and radiation dose of abdomen–pelvis CT protocols with ATCM technique. Were performed five CT protocols using 16-slice and 64-slice scanners, an anthropomorphic phantom for dosimetric measurements, an analytical phantom and retrospective examinations for image quality analysis. Were found significant reduction in effective dose. The highest absorbed doses were found in the stomach and spleen (56.1 and 47.2 mGy, respectively). Objective parameters as noise, low contrast and spatial resolution did not significantly differ between the protocols (p > 0.05). All protocols received the range of ‘Optimum/Acceptable’ in patient’s image quality analysis. This methodology can be reproduced in any clinical routine to optimize CT protocols.

scholarly journals Digital orthodontic radiographic set versus cone-beam computed tomography: an evaluation of the effective dose

2016 ◽  
Vol 21 (4) ◽  
pp. 66-72 ◽  
Author(s):  
Lillian Atsumi Simabuguro Chinem ◽  
Beatriz de Souza Vilella ◽  
Cláudia Lúcia de Pinho Maurício ◽  
Lucia Viviana Canevaro ◽  
Luiz Fernando Deluiz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
New York ◽  
Effective Dose ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Radiological Protection ◽  
Anthropomorphic Phantom ◽  
Thermoluminescent Dosimeters ◽  
Optimization Principle ◽  
Effective Doses

ABSTRACT Objective: The aim of this study was to compare the equivalent and effective doses of different digital radiographic methods (panoramic, lateral cephalometric and periapical) with cone-beam computed tomography (CBCT). Methods: Precalibrated thermoluminescent dosimeters were placed at 24 locations in an anthropomorphic phantom (Alderson Rando Phantom, Alderson Research Laboratories, New York, NY, USA), representing a medium sized adult. The following devices were tested: Heliodent Plus (Sirona Dental Systems, Bernsheim, Germany), Orthophos XG 5 (Sirona Dental Systems, Bernsheim, Germany) and i-CAT (Imaging Sciences International, Hatfield, PA, USA). The equivalent doses and effective doses were calculated considering the recommendations of the International Commission of Radiological Protection (ICRP) issued in 1990 and 2007. Results: Although the effective dose of the radiographic set corresponded to 17.5% (ICRP 1990) and 47.2% (ICRP 2007) of the CBCT dose, the equivalent doses of skin, bone surface and muscle obtained by the radiographic set were higher when compared to CBCT. However, in some areas, the radiation produced by the orthodontic set was higher due to the complete periapical examination. Conclusion: Considering the optimization principle of radiation protection, i-CAT tomography should be used only in specific and justified circumstances. Additionally, following the ALARA principle, single periapical radiographies covering restricted areas are more suitable than the complete periapical examination.

Optimization of computed tomography urography protocol, 1997 to 2008: Effects on radiation dose

2009 ◽  
Vol 50 (4) ◽  
pp. 446-454 ◽  
Author(s):  
P. Dahlman ◽  
L. Jangland ◽  
M. Segelsjö ◽  
A. Magnusson
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Effective Dose ◽  
Excretory Urography ◽  
Ct Urography ◽  
Tube Current Modulation ◽  
Current Modulation ◽  
Tube Current ◽  
The Mean ◽  
The Impact

Background: Since computed tomography (CT) urography began to replace excretory urography as the primary imaging technique in uroradiology, the collective radiation dose to the patients has increased. Purpose: To examine the changes in the CT urography protocol for investigating suspected urinary tract malignancy between the years 1997 and 2008, and how these changes have influenced the mean effective dose. Material and Methods: The study was based on 102 patients (mean age 66.1±14.8 years, range 31–89 years; 30 female, 72 male) divided into five groups (groups A–E) corresponding to the time points at which changes were made to the CT urography protocol. The mean effective doses were estimated using the ImPACT CT Patient Dosimetry Calculator. Results: The number of scan phases at CT urography was reduced from four to three in 1999, resulting in a reduction of the mean effective dose from 29.9/22.5 (female [F]/male [M]) mSv (group A) to 26.1/18.9 (F/M) mSv (group B). In 2001, mAs settings were adapted to patient size, and the mean effective dose was reduced to 16.8/12.0 (F/M) mSv (group C). In 2005, scans were performed with a multidetector-row CT equipped with automatic tube current modulation in the x- and y-axis (CARE Dose). The effective mAs was also lowered in the unenhanced and excretory phase, yet the mean effective dose increased to 18.2/13.1 (F/M) mSv (group D), since the effective mAs had to be increased in the corticomedullary phase to maintain image quality. In 2008, as tube current modulation in the x-, y-, and z-axis was introduced (CARE Dose4D), the mean effective dose was reduced to 11.7/8.8 (F/M) mSv (group E). Conclusion: This study shows that the individual mean effective dose to patients undergoing CT urography has decreased by 60%, from 29.9/22.5 (F/M) mSv in 1997 to 11.7/8.8 (F/M) mSv in 2008.

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