Radiation Dose from Diagnostic Computed Tomography in Saskatchewan

2009 ◽  
Vol 60 (2) ◽  
pp. 71-78 ◽  
Author(s):  
David A. Leswick ◽  
Nida S. Syed ◽  
Chance S. Dumaine ◽  
Hyun J. Lim ◽  
Derek A. Fladeland
Keyword(s):  
Computed Tomography ◽  
Significant Variation ◽  
Ct Scans ◽  
Dose Length Product ◽  
Volume Computed Tomography ◽  
The United Kingdom ◽  
Canadian Data ◽  
Effective Doses ◽  
Computed Tomography Dose Index ◽  
Dose Levels

Objective To calculate the effective dose from diagnostic computed tomography (CT) scans in Saskatchewan, Canada, and compare with other reported dose levels. Methods Data from CT scans were collected from 12 scanners in 7 cities across Saskatchewan. The patient age, scan type, and selected technique parameters including the dose length product and the volume computed tomography dose index were collected for a 2-week period. This information then was used to calculate effective doses patients are exposed to during CT examinations. Data from 2,061 clinically indicated CT examinations were collected, and of them 1,690 were eligible for analysis. Every examination during a 2-week period was recorded without selection. Results The average provincial estimated patient dose was as follows: head, 2.7 mSv (638 scans; standard deviation [SD], ±1.6); chest, 11.3 mSv (376 scans; SD, ±8.9); abdomen-pelvis, 15.5 mSv (578 scans; SD, ±10.0); abdomen, 11.7 mSv (80 scans; SD, ±11.48), and pelvis, 8.6 mSv (18 scans; SD, ±6.04). Significant variation in dose between the CT scanners was observed ( P = .049 for head, P = .001 for chest, and P = .034 for abdomen-pelvis). Conclusions Overall, the estimated dose from diagnostic CT examinations was similar to other previously published Canadian data from British Columbia. This dose varied slightly from some other published standards, including being higher than those found in a review conducted in the United Kingdom in 2003.

scholarly journals Optimization of head computed tomography scan in a tertiary institution in Edo State, South-South Nigeria

2021 ◽  
Vol 8 (4) ◽  
pp. 225-230
Author(s):  
Chikezie Chukwuemeka Udo ◽  
Akintayo Daniel Omojola ◽  
Chukwuemeka Christian Nzotta
Keyword(s):  
Computed Tomography ◽  
Ct Scanner ◽  
Tertiary Institution ◽  
Dose Length Product ◽  
Volume Computed Tomography ◽  
The United Kingdom ◽  
Ct Protocol ◽  
Tube Current ◽  
Edo State ◽  
Computed Tomography Dose Index

Objective: The study is aimed at optimizing the existing CT protocol for head scans in a Specialist Teaching Hospital in Edo State with a 16-slice Siemens Somatom Emotion scanner. Also, the study determined the volume computed tomography dose index (CTDIvol) and Dose Length Product (DLP) from the patient's dose profiles. The results from this study were compared with relevant studies. Materials and Methods: The scanner was used to acquire head CT of 160 patients retrospectively. Also, a locally designed head phantom was used to simulate individual patients using a similar protocol by changing the tube current (mA) and total scan width (TSW) only from the existing protocol. Results: Percentage dose reduction (PDR) for the CTDIvol and DLP ranged 42.00-46.80% and 37.13-43.54% respectively. The optimized CTDIvol and DLP were lowest compared to studies in the United Kingdom (UK), Italy, India, Ireland, Sudan, Nigeria, European Commission (EC), United States of America (USA) and Japan. Only the DLP for India was lower than our optimized value. Conclusion: The need to understudy CT configuration is necessary, this will allow end-users to optimize certain parameters in the CT scanner, which will reduce the patient dose without compromising image quality

scholarly journals Validation of a Locally Designed Computed Tomography Dose Phantom: A Comparison Study with a Standard Acrylic Phantom in South-South, Nigeria

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Anwuli Christiana Tobi ◽  
Chukwuka Emmanuel Mokobia ◽  
Joyce Ekeme Ikubor ◽  
Akintayo Daniel Omojola
Keyword(s):  
Computed Tomography ◽  
Cylindrical Shape ◽  
Correction Factors ◽  
Energy Agency ◽  
Dose Length Product ◽  
Ct Dose ◽  
Volume Computed Tomography ◽  
The Mean ◽  
Computed Tomography Dose Index ◽  
Dose Measurements

Purpose: The aim of this study was to determine the mean volume computed tomography dose index (CTDIvol) for the standard head and body phantoms and locally designed head and body phantoms respectively. Similarly, this study determined and compared the displayed mean CTDIvol and Dose Length Product (DLP) for the above phantoms from the CT monitor. In addition, the percentage deviations of both phantoms were compared with the recommended limits from the International Atomic Energy Agency (IAEA) and the American College of Radiologists (ACR). Materials and Methods: Dose measurements were made using a standard polymethymethacrylate (PMMA) phantom for head and body as well as a locally designed phantom with four CT scanners using thermoluminescence dosimeters (TLDs). The locally designed phantoms were made using a PMMA sheet, which was bent to give the desired cylindrical shape and was made like the standard phantoms. The constructed phantom was filled with water and the TLD chips were inserted into the center and peripheries of the phantoms to obtain the absorbed doses. Results: The CTDIvol for the standard head and body phantom for center A was 66.97 and 21.85mGy and for B was 23.39 and 6.29mGy respectively. Similarly, the CTDIvol for the constructed head and body phantom for center A was 63.91 and 19.84mGy and for B was 24.67 and 6.30mGy respectively. The uncertainty between the standard and constructed head phantoms for centers A and B was 4.6 and 5.5% respectively, while that of the standard and constructed body phantoms for centers A and B was 9.2 and 0.0% respectively. The maximum percent deviation from the console CTDIvol and DLP values with the four phantoms for centers A and B was within ±20%. The mean correction factors for the head and body were 0.998 and 1.05 respectively. Conclusion: The uncertainties obtained in this study were within the IAEA and ACR recommended value of ±20%. The constructed phantom proved useful for CT dose measurements.

VOLUME CT DOSE INDEX AND DOSE-LENGTH PRODUCT VALUES ACCORDING TO FACILITY SIZE IN JAPAN

2020 ◽  
Vol 188 (2) ◽  
pp. 261-269
Author(s):  
Yuta Matsunaga ◽  
Yuya Kondo ◽  
Kenichi Kobayashi ◽  
Masanao Kobayashi ◽  
Kazuyuki Minami ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Dose ◽  
Volume Computed Tomography ◽  
Ct Dose Index ◽  
Computed Tomography Dose Index ◽  
Facility Size ◽  
Dose Index

Abstract The aim of this study was to investigate differences in volume computed tomography dose index (CTDIvol) and dose-length product (DLP) values according to facility size in Japan. A questionnaire survey was sent to 3000 facilities throughout Japan. Data from each facility were collected including bed number, computed tomography (CT) scan parameters employed and the CTDIvol and/or DLP values displayed on the CT scanner during each examination. The CTDIvol and DLP for 11 adult and 6 paediatric CT examinations were surveyed. Comparison of CTDIvol and DLP values of each examination according to facility size revealed key differences in CT dose between small and large facilities. This study highlights the importance of lowering the dose of coronary artery examination with contrast agent in smaller facilities and of lowering the dose of adult and paediatric head CT without contrast agent in larger facilities. The results of this study are valid in Japan.

ADULT CT EXAMINATIONS IN ALGERIA: TOWARDS UPDATING NATIONAL DIAGNOSTIC REFERENCE LEVELS

2020 ◽  
Vol 190 (4) ◽  
pp. 364-371
Author(s):  
Nadia Khelassi-Toutaoui ◽  
Ahmed Merad ◽  
Virginia Tsapaki ◽  
Fouzia Meddad ◽  
Zakia Sakhri-Brahimi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Doses ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Dose Length Product ◽  
Institutional Evaluation ◽  
Starting Point ◽  
First Results ◽  
Ct Radiation ◽  
Computed Tomography Dose Index

Abstract A pilot study has concerned the most frequent computed tomography examinations (CT). This represents the first results based on actual survey for diagnostic reference levels (DRLs) establishment in Algeria. A total number of 2540 patients underwent this survey that has included the recording of CT parameters, computed tomography dose index (CTDIvol) and dose-length product of the head, thorax, abdomen, abdomen–pelvis (AP), lumbar spine (LS) and thorax–abdomen–pelvis (TAP) performed on standard patients. The proposed DRLs are 71 mGy/1282 mGy.cm for head, 16 mGy/555 mGy.cm for thorax, 18 mGy/671 mGy.cm for abdomen, 21 mGy/950 mGy.cm for AP, 36 mGy/957 mGy.cm for LS and 18 mGy/994 mGy.cm for TAP. The rounded 75th percentile seems to be higher in some examinations compared to the literature. Our findings confirm the need to optimise our practice. These results provide a starting point for institutional evaluation of CT radiation doses.

scholarly journals The comparison of bolus tracking and test bolus techniques for computed tomography thoracic angiography in healthy beagles

2013 ◽  
Vol 84 (1) ◽  
Author(s):  
Nicolette Cassel ◽  
Ann Carstens ◽  
Pieter Becker
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Test Dose ◽  
Dose Length Product ◽  
Bolus Tracking ◽  
Iodinated Contrast ◽  
Iodinated Contrast Agent ◽  
Test Bolus ◽  
The Mean ◽  
Computed Tomography Dose Index

Computed tomography thoracic angiography studies were performed on five adult beagles using the bolus tracking (BT) technique and the test bolus (TB) technique, which were performed at least two weeks apart. For the BT technique, 2 mL/kg of 300 mgI/mL iodinated contrast agent was injected intravenously. Scans were initiated when the contrast in the aorta reached 150 Hounsfield units (HU). For the TB technique, the dogs received a test dose of 15% of 2 mL/kg of 300 mgI/mL iodinated contrast agent, followed by a series of low dose sequential scans. The full dose of the contrast agent was then administered and the scans were conducted at optimal times as identified from time attenuation curves. Mean attenuation in HU was measured in the aorta (Ao) and right caudal pulmonary artery (rCPA). Additional observations included the study duration, milliAmpere (mA), computed tomography dose index volume (CTDI[vol]) and dose length product (DLP). The attenuation in the Ao (BT = 660 52 HU ± 138 49 HU, TB = 469 82 HU ± 199 52 HU, p = 0.13) and in the rCPA (BT = 606 34 HU ± 143 37 HU, TB = 413 72 HU ± 174.99 HU, p = 0.28) did not differ significantly between the two techniques. The BT technique was conducted in a significantly shorter time period than the TB technique (p = 0.03). The mean mA for the BT technique was significantly lower than the TB technique (p = 0.03), as was the mean CTDI(vol) (p = 0.001). The mean DLP did not differ significantly between the two techniques (p = 0.17). No preference was given to either technique when evaluating the Ao or rCPA but the BT technique was shown to be shorter in duration and resulted in less DLP than the TB technique.

Does gantry rotation time influence accuracy of volume computed tomography dose index (CTDI vol ) in modern CT?

2017 ◽  
Vol 37 ◽  
pp. 43-48 ◽  
Author(s):  
Atsushi Fukuda ◽  
Nao Ichikawa ◽  
Yoshiharu Fujita ◽  
Pei-Jan Paul Lin ◽  
Kosuke Matsubara ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Rotation Time ◽  
Volume Computed Tomography ◽  
Computed Tomography Dose Index ◽  
Dose Index

scholarly journals Patient doses in computed tomography: An assessment of local diagnostic reference levels in a large teaching hospital

2012 ◽  
Vol 27 (3) ◽  
pp. 305-310 ◽  
Author(s):  
Darka Hadnadjev ◽  
Danijela Arandjic ◽  
Sanja Stojanovic ◽  
Olivera Ciraj-Bjelac ◽  
Predrag Bozovic ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Dose Reduction ◽  
Teaching Hospital ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Dose Length Product ◽  
Large Teaching Hospital ◽  
Tube Current ◽  
Patient Doses ◽  
Computed Tomography Dose Index

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.

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.

DIAGNOSTIC REFERENCE LEVELS FOR PAEDIATRIC HEAD COMPUTED TOMOGRAPHY IN MOROCCO: A NATIONWIDE SURVEY

2020 ◽  
Vol 191 (4) ◽  
pp. 400-408
Author(s):  
M Benmessaoud ◽  
A Dadouch ◽  
M Talbi ◽  
M Tahiri ◽  
Y El-ouardi
Keyword(s):  
Computed Tomography ◽  
Nationwide Survey ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Dose Length Product ◽  
Head Ct ◽  
Ct Dose ◽  
Starting Point ◽  
Effective Doses ◽  
Head Computed Tomography

Abstract The purpose of this study was to establish the diagnostic reference levels (DRLs) for paediatric head computed tomography (CT) in Morocco and to assess the effective doses received during head CT examinations. The data of 1007 patients were collected retrospectively from Moroccan university children’s hospitals. The sample was classified per age group:<1, 1–5, 5–10 and 10–15 years. The proposed DRLs were defined as 75th percentile of the distributions, which were in terms of CT dose index of 26.98, 28.88, 34.00 and 38.20 mGy and dose length product of 461.64, 540.06, 627.20 and 705.98 mGy.cm, respectively. The effective doses estimated were 3.6, 2.9, 2 and 1.79 mSv, respectively. The DRLs reported in Morocco were compared with those of other countries, which were based on the same age grouping method, including Thailand, Switzerland, Japan and the international DRLs. Our initiative via the determination of the first Moroccan diagnostic reference levels for paediatric head CT must be a starting point to spread this investigation towards other examinations and imaging modalities.

EVALUATION OF IRRADIATION DOSES DELIVERED TO PATIENTS IN COMPUTED TOMOGRAPHY EXAMINATIONS IN 10 RADIOLOGY DEPARTMENTS IN DOUALA-CAMEROON

2020 ◽  
Vol 191 (3) ◽  
pp. 288-295
Author(s):  
Celestin Mpeke Mokubangele ◽  
Alexandre Ngwa Ebongue ◽  
Francisse Ouogue ◽  
Daniel Bongue ◽  
Boniface Moifo
Keyword(s):  
Computed Tomography ◽  
Ct Scan ◽  
Pediatric Population ◽  
Adult Population ◽  
Daily Practice ◽  
Ct Scans ◽  
Radiological Protection ◽  
Dose Length Product ◽  
Need To Evaluate ◽  
Adults And Children

Abstract Computed tomography (CT) scan is currently the most irradiating radio diagnostic procedure for the patients. The effective dose delivered by a CT-scan exploration corresponds to 1–20 years of natural irradiation of an individual. Hence, there is need to evaluate this medical exposure, in order to provide indicators and propose guidelines for its daily practice. The purpose of this work was to assess patient exposure levels due to CT-scan exams and propose a local diagnostic reference levels for the most common CT examinations performed in the radiology units of Douala/Cameroon. Data from 1775 CT scans, amongst which 10 different types of common CT examinations on adults and children, were collected, of which 1378 were adult CT scans and 397 were pediatric CT scans. The dose-length product (DLP) values in the adult population for head, abdomen–pelvic and lumber spine CT scans were high as compared to the Institute for Radiological Protection and Nuclear Safety recommendations and previous local DRL with an increase of 36, 15 and 23%, respectively. A general decrease of the DLP for CT-scans examinations in the pediatric population was observed.

Sign in / Sign up

Export Citation Format

Share Document