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.

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

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 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.

TOWARD NATIONAL CT DIAGNOSTIC REFERENCE LEVELS IN THE UNITED ARAB EMIRATES: A MULTICENTER REVIEW OF CT DOSE INDEX AND DOSE LENGTH PRODUCT

2020 ◽  
Vol 190 (3) ◽  
pp. 243-249
Author(s):  
Mohamed M Abuzaid ◽  
Wiam Elshami ◽  
A El Serafi ◽  
T Hussien ◽  
J R McConnell ◽  
...  
Keyword(s):  
Computed Tomography ◽  
United Arab Emirates ◽  
Patient Characteristics ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Dose Length Product ◽  
Ct Dose ◽  
Ct Head ◽  
Computed Tomography Dose Index ◽  
Dose Index

Abstract This multicenter study evaluated computed tomography dose index volume (CTDIvol) and dose length product (DLP) to contribute to establishing computed tomography (CT) national diagnostic reference levels (NDRLs) in the United Arab Emirates (UAE). Data from 240 patients, who underwent CT head, chest, abdomen–pelvis and urography examinations, were analyzed, including patient age, sex and weight, CTDIvol (mGy) and DLP (mGy cm). The proposed DRLs for each examination were calculated as the third quartile. DRLs are proposed using CTDIvol (mGy) and DLP (mGy cm) for CT head (67 and 1189, respectively), chest (8 and 302, respectively), abdomen–pelvis (28 and 1122, respectively) and urography (20 and 714, respectively). These values are comparable with the initial NDRLs and published international DRLs. Baseline values for International Radiology Center (IRC) CT DRLs were calculated on frequently performed CT examinations. Implementation of DRL values improves dose optimization based on procedures, scanner type and patient characteristics while maintaining acceptable image quality and diagnostic confidence.

scholarly journals Paediatric CT Dose Optimization in a General Hospital

2019 ◽  
Vol 13 (1) ◽  
pp. 138
Author(s):  
Vivian Heidorne Guerra ◽  
Denise Yanikian Nersissian ◽  
Camila Souza Melo ◽  
Caio Vasconcellos ◽  
Rebeca Gonçalves Freitas ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pediatric Patients ◽  
Optimization Process ◽  
Diagnostic Image Quality ◽  
Dose Length Product ◽  
Diagnostic Image ◽  
Ct Dose ◽  
Computed Tomography Scans ◽  
Absorbed Radiation Dose ◽  
Computed Tomography Dose Index

This work presents a methodology for the optimization of protocols applied to pediatric patients who underwent brain and chest computed tomography examinations. The implementation of this methodology aims to reduce the dose of ionizing radiation delivered to patients and the consequent risk associated with radiation, without decreasing the diagnostic image quality. The comparison between the results of CTDIvol (computed tomography dose index) and DLP (dose-length product) dosimetric quantities before the optimization process and their corresponding results after the implementation of the optimization process was done through boxplot graphs. It is noteworthy that the implementation of this methodology allows reductions in the range between 18 and 50% of the dosimetric values evaluated in this study. In addition, the case of brain computed tomography scans, in which the cohort of the evaluated patients is larger, is a highlight, which should also reflect in the reduction of the absorbed radiation dose by this particularly important group of patients.

scholarly journals Chest CT Dose Examination for Adult Patient in Abuja and Keffi, Hospitals in Nigerian

2020 ◽  
pp. 1-9
Author(s):  
U. Rilwan ◽  
G. C. Onuchukwu ◽  
I. Umar ◽  
L. K. Sabiu ◽  
H. A. Abdullahi
Keyword(s):  
Computed Tomography ◽  
European Commission ◽  
Single Photon ◽  
Photon Emission ◽  
Reference Level ◽  
Dose Optimization ◽  
Emission Computed Tomography ◽  
Dose Length Product ◽  
Ct Dose ◽  
The Mean

The term "computed tomography" (CT) is often used to refer to X-ray CT, because it is the most commonly known form. But, many other types of CT exist, such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This study was carried out in the north central part of Nigeria which includes Abuja and Keffi (Nasarawa State). This study has established local diagnostic reference levels (LDRLs). Dose report and scan parameters for chest was assessed during the period (January – July, 2016) of seven months at the three study centres (A, B and C in which two are located in Abuja and the other one (C) located in Keffi. Data on CT Dose index (CTDIw) and dose length product (DLP) available and achieved on CT scanner control console was recorded for a minimum of 10 average sized patients for each facility to established a local Diagnostic reference level (LDRLs) and radiation dose optimization Data was collected using a purposive sampling technique, from 131 adult patients weighing 70±3kg) from Philip brilliance, Toshiba Alexion and General Electric (GE) CT scanners for this study. Third quartile values of the estimated LDRLs for CTDIw and DLP was determined as 10.9 mGy and 432.8 mCy*cm. The mean CTDIw obtained are lower to the reported data from the European Commission of 30mGy. The mean DLP are comparably lower than all the reported value from the European commission of 650mGy/cm. Therefore, there is no any clinical implication and hence CT dose optimization is recommended.

Comparison of Radiation Dose in CT Examinations At PIMS with European Commission Reference Doses

2021 ◽  
Vol 17 (3) ◽  
pp. 216-221
Author(s):  
Fawad Yasin ◽  
Anum Rasheed ◽  
Muhammad Nauman Malik ◽  
Farheen Raza ◽  
Ramish Riaz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
European Commission ◽  
Large Scale ◽  
Radiology Department ◽  
Radiation Doses ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Dose Length Product ◽  
Ct Dose

OBJECTIVE - The purpose of this study was to assess the radiation dose levels from common computed tomography (CT) examinations performed in Radiology Department of Pakistan Institute of Medical Sciences (PIMS), and evaluate these according to diagnostic reference levels (DRLs) proposed by European Commission (EC) guidelines, and thus contributing towards the establishment of local and national DRLs. To the best of our knowledge, this is the first study of its kind to explore radiation doses from CT examinations in Pakistan. STUDY DESIGN - This was a quantitative study conducted at PIMS, Islamabad, spanning a duration of eight weeks. Scan parameters and dose profile data of 1506 adults undergoing examinations of head, neck, chest and abdomen-pelvis regions, comprising of single- and multi-phase, contrast-enhanced and unenhanced studies. Dose indicators utilized by EC guidelines for DRLs include volume CT dose index (CTDIvol) and Dose Length Product (DLP) for single slice and complete examination radiation doses, respectively. METHOD - Values of CTDIvol, DLP and scan lengths were extracted from the CT operators console. Other control variables included gender, contrast enhancement and phasicity of study. IBM SPSS package was used to obtain descriptive statistics such as mean and quartiles. RESULTS - DRLs calculated as 75th percentile of CTDIvol, DLP for various anatomical regions are by and far comparable to European DRLs. CONCLUSION – This study describes institutional diagnostic reference levels for common CT exams in Islamabad and provides benchmark values for future reference. Our DRL values are mostly comparable to European and international DRLs. Similar, albeit large scale, surveys are recommended for establishment of local and national DRLs, eventually contributing towards development of regional DRLs. KEYWORDS: CTDIvol, DLP, Diagnostic Reference Levels, Computed Tomography, Radiation Monitoring, Scan length

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.

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
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