PATIENT DOSE SURVEY BASED ON SIZE-SPECIFIC DOSE ESTIMATE AND ACCEPTABLE QUALITY DOSE IN CHEST AND ABDOMEN/PELVIS CT EXAMINATIONS

2019 ◽  
Vol 185 (2) ◽  
pp. 176-182
Author(s):  
Ali Mehdipour ◽  
Masoumeh Parsi ◽  
Faezeh-Sadat Khorram
Keyword(s):  
Optimization Methods ◽  
Patient Dose ◽  
Dose Optimization ◽  
Standard Size ◽  
Dose Length Product ◽  
Dose Estimate ◽  
Ct Dose ◽  
Acceptable Quality ◽  
Patient Size ◽  
Patient Doses

Abstract The practical aspects of two recently developed patient dose optimization methods in computed tomography (CT) examinations, size-specific dose estimate (SSDE) and acceptable quality dose (AQD), were verified for the chest and abdomen/pelvis examinations. A dose survey was performed in a CT institute by considering patients lateral diameter, weight and body mass index (BMI). The AQD tables for weight and BMI groups and SSDE threshold curves were obtained. The mean of volume CT dose index and dose length product for standard-size patients were compared with the national diagnostic reference levels (NDRLs) of Iran. The results show that patient doses are below the NDRLs. It is more reliable to report the AQDs based on SSDE and for BMI groups which can well take into account patient size in the dose optimization process. The SSDE threshold curves can be determined with more precision by including dose data of all possible sizes in the curves.

scholarly journals Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

2019 ◽  
Vol 25 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Daryoush Khoramian ◽  
Soroush Sistani ◽  
Peyman Hejazi
Keyword(s):  
Cervical Spine ◽  
The Other ◽  
Reference Level ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Dose ◽  
Patient Doses ◽  
Ct Dose Index ◽  
Ct Scanners ◽  
Dose Levels

Abstract Objective: The literature has approved that the use of the concept of diagnostic reference level (DRL) as a part of an optimization process could help to reduce patient doses in diagnostic radiology comprising the Computed Tomography (CT) examinations. There are four public/governmental CT centers in the province (Semnan, Iran) and, to our knowledge, after about 12 years since the launch of the first CT scanner in the province there is no dosimetry information on those CT scanners. The aim of this study was to evaluate CT dose indices with the aim of the establishment of the DRL for head, chest, cervical spine, and abdomen-pelvis examinations. Methods: Scan parameters of 381 patients were collected during two months from 4 CT scanners. The CT dose index (CTDI) was measured using a calibrated ionization chamber on two cylindrical poly methyl methacrylate (PMMA) phantoms. For each sequences, weighted CTDI (CTDIw), volumetric CTDI (CTDIv) and dose length product (DLP) were calculated. The 75th percentile was proposed as the criterion for DRL values. Results: Proposed DRL (CTDIw, CTDIv, DLP) for the head, chest, cervical spine, and abdomen-pelvis were (46.1 mGy, 46.1 mGy, 723 mGy × cm), (13.8 mGy, 12.0 mGy, 377 mGy × cm), (40.0 mGy, 40.0 mGy, 572 mGy × cm) and (14.9 mGy, 12.1 mGy, 524 mGy × cm), respectively. Conclusion: Comparison with the others results from the other countries indicates that the head, chest and abdomen-pelvis scans in our region are lower or in the range of the other studies investigated in terms of dose. In the case of cervical spine scanning it’s necessary to review and regulate scan protocols to reach acceptable dose levels.

scholarly journals A simple manual method to estimate water-equivalent diameter for calculating size-specific dose estimate in chest computed tomography

2021 ◽  
Vol 94 (1117) ◽  
pp. 20200473
Author(s):  
Dimitris Mihailidis ◽  
Virginia Tsapaki ◽  
Pelagia Tomara
Keyword(s):  
Radiation Dose ◽  
Computer Programming ◽  
Chest Ct ◽  
Patient Dose ◽  
Equivalent Diameter ◽  
Effective Diameter ◽  
Manual Method ◽  
Dose Estimate ◽  
Patient Size ◽  
Patient Radiation Dose

Objectives: The American Association of Physicists in Medicine (AAPM) Task Groups (TG) 204 and 220 introduced a method to estimate patient dose by introducing the Size-Specific Dose Estimate (SSDE). They provided patient size-specific conversion factors that could be applied to volumetric CT Dose Index CTDIvol to estimate patient dose in terms of SSDE based on either effective diameter (Deff) or water equivalent diameter (Dw). Our study presented an alternative method to manually estimate SSDE for the everyday clinical routine chest CT that can be readily used and does not require sophisticated computer programming. Methods: For 16 adult patients undergoing chest CT, the method employed an average relative electron density (ρelung = 0.3) for the lung tissue and a ρetissue of 1.0 for the other tissues to scale the lateral thickness and compute the effective lateral thickness on the patient’s axial image. The proposed method estimated a “corrected” Deff (Deffcorr) to replace Dw and compared results with TG220 and a second method proposed by Huda et al, for the same set of CT studies. Results: The results showed comparable behavior for all methods. There is overall agreement especially between this study and TG220. Largest differences were +13.3% and+15.9% from TG220 and Huda values, respectively. Patient size correlation showed strong correlation with the TG220 and Huda et al methods. Conclusions: A simple, quick manual method to estimate CT patient radiation dose in terms of SSDE was proposed as an alternative where sophisticated computer programming is not available. It can be readily used during any clinical chest CT scanning. Advances in knowledge: The paper is novel as it presents simple, quick manual method to estimate CT patient radiation dose in chest imaging. The process can be used as alternative in cases no sophisticated computer programming is available.

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

2020 ◽  
pp. 36-44
Author(s):  
U. Rilwan ◽  
G. C. Onuchukwu ◽  
L.K. Sabiu ◽  
H. A. Abdullahi ◽  
I. Umar
Keyword(s):  
European Commission ◽  
Sampling Technique ◽  
Reference Level ◽  
Dose Optimization ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Dose ◽  
Control Console ◽  
The Mean ◽  
Reported Data

This study has established local diagnostic reference levels (LDRLs). Dose report and scan parameters for abdomen was assessed during the period of seven months at the three study centres. 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±3 kg) 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 12.7 mGy and 560 mGy*cm. The mean CTDIw obtained are lower to the reported data from the European Commission of 35 mGy. The mean DLP are comparably lower than all the reported value from the European commission of 780 mGy/cm. Therefore, there is no any clinical implication and hence CT dose optimization is recommended.

Establishment of national diagnostic reference levels (NDRL) for computed tomographic (CT) procedures in Sri Lanka: first nation-wide dose survey

2021 ◽  
Author(s):  
T Amalaraj ◽  
Duminda Satharasinghe ◽  
Aruna Pallewatte ◽  
Jeyasingam Jeyasugiththan
Keyword(s):  
Sri Lanka ◽  
Diagnostic Reference Levels ◽  
Reference Levels ◽  
Standard Size ◽  
Dose Length Product ◽  
Computed Tomographic ◽  
Ct Dose ◽  
Contrast Enhanced ◽  
Ct Dose Index ◽  
First Time

Abstract The main purpose of this study was to establish the national diagnostic reference levels (NDRLs) for common CT procedures for the first time in Sri Lanka. Patient morphometric, exposure parameters, and dose data such as volume CT dose index (CTDIvol) and dose length product (DLP) were collected from 5666 patients who underwent 22 procedure types. The extreme dose values were filteblue before analysis to ensure that the data comes from standard size patients. The median of the dose distribution was calculated for each institution, and the third quartile value of the median distribution was consideblue as the NDRL. Based on the inclusion and exclusion criteria, 4592 patients data from 17 procedure types were consideblue for NDRL establishment covering 41\% of the country's total CT machines. The proposed NDRLs based on CTDIvol and DLP for non-contrast (NC) head:82.2 mGy/1556 mGy.cm, contrast-enhanced (CE) head: 82.2 mGy/1546 mGy.cm, chest-NC:7.4 mGy/350 mGy.cm, chest-CE:8.3 mGy/464 mGy.cm, abdomen NC:10.5 mGy/721 mGy.cm, abdomen arterial (A) phase:13.4 mGy/398 mGy.cm, abdomen venous (V) phase:10.8 mGy/460 mGy.cm, abdomen delay (D) phase:12.6 mGy/487 mGy.cm, sinus NC:30.2 mGy/452 mGy.cm, lumbar spine--NC:24.1 mGy/1123 mGy.cm, neck-NC:27.5 mGy/670 mGy.cm, high resolutions CT (HRCT) of chest:10.3 mGy/341 mGy.cm, kidney, ureter and bladder (KUB) NC:19.4 mGy/929 mGy.cm, chest to pelvis (CAP) NC:10.8 mGy/801 mGy.cm, CAP-A:10.4 mGy/384 mGy.cm, CAP-V:10.5 mGy/534 mGy.cm and CAP-D:16.8 mGy/652 mGy.cm. Although the proposed NDRLs are comparable with other countries, the observed broad dose distributions between the CT machines within the country indicate that dose optimisation strategies for Sri Lanka should be implemented for most of the CT facilities.

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

2020 ◽  
pp. 8-13
Author(s):  
U. Rilwan ◽  
G. C. Onuchukwu ◽  
H. A. Abdullahi ◽  
I. Umar ◽  
L.K. Sabiu
Keyword(s):  
European Commission ◽  
Sampling Technique ◽  
Reference Level ◽  
Dose Optimization ◽  
Ct Scanner ◽  
Dose Length Product ◽  
Ct Dose ◽  
Control Console ◽  
The Mean ◽  
Reported Data

This study has established local diagnostic reference levels (LDRLs). Dose report and scan parameters for the head was assessed during seven months at the three study centres. 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 establish 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. The collected data were analyzed using SPPSS version (20) statistical software. Third quartile values of the estimated LDRLs for CTDIw and DLP was determined as 49.8 mGy and 9639 mGy. The mean CTDIw obtained are lower to the reported data from the European Commission of 60mGy. The mean DLP are comparably lower than all the reported value from the European commission of 1050 mGy. Therefore, CT dose optimization is recommended.

Reduced Kilovoltage in Computed Tomography–Guided Intervention in a Community Hospital: Effect on the Radiation Dose

2014 ◽  
Vol 65 (4) ◽  
pp. 345-351 ◽  
Author(s):  
Saman Rezazadeh ◽  
Steven J. Co ◽  
Simon Bicknell
Keyword(s):  
Low Dose ◽  
Effective Diameter ◽  
Tube Voltage ◽  
Dose Length Product ◽  
Ct Guided ◽  
Ct Dose ◽  
Patient Size ◽  
Ct Dose Index ◽  
Volume Ct ◽  
Dose Index

Purpose The purpose of this study was to determine whether low-kilovoltage (80 or 100 kV) computed tomography (CT)-guided interventions performed in a community-based hospital are feasible and to compare radiation exposure incurred with conventional 120 kV potential. Materials and Methods Effective doses (ED) received by patients who underwent CT-guided intervention were analysed before and after a low-dose kilovoltage protocol was instituted in our department. We performed CT-guided procedures of 93 consecutive patients by using conventional 120-kV tube voltage (50 patients) and a low voltage of 80 or 100 kV for the remainder of this cohort. Automatic tube current modulation was enabled to obtain the best image quality. Procedure details were prospectively recorded and included examination site and type, slice width, tube voltage and current, dose length product, volume CT dose index, and size-specific dose estimate. Dose length product was converted to ED to account for radiosensitivity of specific organs. Statistical comparisons with test differences in the ED, volume CT dose index, size-specific dose estimate, and effective diameter (patient size) were made by using the Student t test. Results All but 6 of the procedures performed at 80 kV were successful, for a success rate of 86%. At lower voltages, the ED was significantly ( P < .01) reduced, on average, by 57%, 73%, and 65% for the pelvic, chest, and abdomen procedures, respectively. Conclusion A low-dose radiation technique by using 80 or 100 kV results in a high technical success rate for pelvic, chest, and abdomen CT-guided interventional procedures, although dramatically decreasing radiation exposure. There was no significant difference in effective diameter (patient size) between the conventional and the low-dose groups, which would suggest that dose reduction was indeed a result of kVp change and not patient size.

scholarly journals The comparison of size-specific dose estimate in CT examination based on head and body PMMA phantom

2018 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
Mohd Hanafi Ali ◽  
Choirul Anam ◽  
Freddy Haryanto ◽  
Geoff Dougherty
Keyword(s):  
Equivalent Diameter ◽  
Correction Factors ◽  
K Value ◽  
Dose Estimate ◽  
Light Speed ◽  
Ct Examination ◽  
Ct Dose ◽  
Patient Size ◽  
Ct Dose Index ◽  
The Impact

Nowadays, a dose estimate for individual patients undergoing CT examination is carried out using the metric of size-specific dose estimate (SSDE), which is calculated by multiplying a volume CT dose index (CTDIvol) and a correction factor that is a function of patient size. Two CTDIvol values are based on head and body PMMA phantoms. There are also two values of correction factors (k), both for head and body PMMA phantoms. The purpose of this study was to compare the SSDE values calculated using head and body PMMA phantoms with their corresponding correction factors (k). The CTDIvol values were derived from the ImPACT 1.04 software for 12 CT scanners: Sensation 4, Sensation 16, Sensation 64, Light Speed, Light Speed 16, Light Speed VCT, Secura, Brilliance 16, Brilliance 64, Asteion Dual, Aquilion 4, and Aquilion 16. The size of the patients who underwent CT examination was characterized by a water-equivalent diameter (Dw) from 10 cm to 45 cm. The results indicated that the differences in SSDE values based on head and body CTDIvol were within 20%. Thus, the SSDE value can be calculated using the head or body CTDIvol bases with corresponding k value.

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.

USE OF CLINICAL EXPOSURE INDEX AND DEVIATION INDEX BASED ON NATIONAL DIAGNOSTIC REFERENCE LEVEL AS DOSE-OPTIMIZATION TOOLS FOR GENERAL RADIOGRAPHY IN KOREA

2020 ◽  
Vol 191 (4) ◽  
pp. 439-451
Author(s):  
Hyemin Park ◽  
Yongsu Yoon ◽  
Jungmin Kim ◽  
Jungsu Kim ◽  
Hoiwoun Jeong ◽  
...  
Keyword(s):  
Patient Dose ◽  
Reference Level ◽  
Dose Optimization ◽  
International Electrotechnical Commission ◽  
Exposure Index ◽  
Clinical Exposure ◽  
Deviation Index ◽  
Clinical Environments ◽  
Anterior Posterior ◽  
Exposure Conditions

Abstract The International Electrotechnical Commission introduced the concepts of exposure index (EI), target exposure index (EIT) and deviation index (DI) to manage and optimize patient dose in real time. In this study, we have proposed an appropriate method for setting the EIT based on the Korean national diagnostic reference levels (DRLs). Furthermore, we evaluated the use of clinical EI, EIT and DI as tools for patient dose optimization in clinical environments by observing the changes in DI with those in EIT. According to the Korean national exposure conditions, we conducted experiments on three representative radiographic examinations (chest posterior–anterior, lateral and abdomen anterior–posterior) of clinical environments. As the exposure conditions and DRLs varied, the clinical EI, EIT and DI also varied. These results reveal that the clinical EI, EIT and DI can be used as tools for optimizing the patient dose if EIT is periodically and properly updated.

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