Estimation Of Effective Dose Research Articles

Estimation of Inhaled Effective Doses of Uranium and Thorium for Workers in Bayan Obo Ore and the Surrounding Public, Inner Mongolia, China.

Uranium and thorium are two common natural radioactive elements with high concentrations in Earth’s crust. The main aim of this study is to estimate the inhaled effective dose of uranium and thorium caused by a typical radioactive rare earth ore to the occupational population and the surrounding public. The particulate matter (PM) concentrations in the atmosphere of four typical workplaces and one surrounding living area were obtained by a high-flow sampling equipment with a natural cellulose filter membrane. The critical parameter for the inhaled effective dose estimation—the activity median aerodynamic diameter (AMAD)—was determined. The AMAD values of uranium and thorium in the atmosphere PM were 3.36 and 3.64 μm, respectively. The estimated median effective dose caused by inhalation thorium among the occupational population ranged from 15.3 to 269.0 μSv/a, and the corresponding value for the surrounding public was 2.3 μSv/a. All values for the effective dose caused by the inhalation of uranium were in the nSv magnitude.

Radon Activity Concentrations in Natural Hot Spring Water: Dose Assessment and Health Perspective.

The world community has long used natural hot springs for tourist and medicinal purposes. In Indonesia, the province of West Java, which is naturally surrounded by volcanoes, is the main destination for hot spring tourism. This paper is the first report on radon measurements in tourism natural hot spring water in Indonesia as part of radiation protection for public health. The purpose of this paper is to study the contribution of radon doses from natural hot spring water and thereby facilitate radiation protection for public health. A total of 18 water samples were measured with an electrostatic collection type radon monitor (RAD7, Durridge Co., USA). The concentration of radon in natural hot spring water samples in the West Java region, Indonesia ranges from 0.26 to 31 Bq L−1. An estimate of the annual effective dose in the natural hot spring water area ranges from 0.51 to 0.71 mSv with a mean of 0.60 mSv for workers. Meanwhile, the annual effective dose for the public ranges from 0.10 to 0.14 mSv with an average of 0.12 mSv. This value is within the range of the average committed effective dose from inhalation and terrestrial radiation for the general public, 1.7 mSv annually.

Comparison of different methods of estimating the effective dose and the ambient dose equivalent for neutrons from measured prompt gamma intensities

Estimations of the ambient dose equivalent H∗10 and the effective dose (anterior–posterior)​ EAP from prompt gamma intensities are investigated theoretically using Monte Carlo simulations. The system considered consists of a NaI(Tl) gamma detector to measure prompt gamma intensities emitted due to neutron irradiation from a high density polyethylene (HDPE) cylinder embedded in a hollow borated-HDPE cylinder and covered by a layer of lead. A comparative evaluation of different computational techniques of dose estimation, such as, the multiple linear regression method, the detector response-matrix inversion method and the convolution of the unfolded neutron energy distributions with the fluence to dose conversion coefficients (DCC) provided by the International Commission on Radiological Protection (ICRP) is done. The dose estimations are done using the prompt gamma responses (response matrix) obtained for the five distinct gamma peak intensities (boron, hydrogen, carbon and 2 from lead) emitted from the system for incident mono-energetic neutrons ranging from 0.01 eV to 1 GeV. Different workplace neutron spectra are used for the estimation of ambient dose and effective dose to evaluate performances of these three dose estimation methods. The doses (H∗10 and EAP) estimated using the convolution of the unfolded neutron spectra with the DCC-ICRP result in satisfactory and accurate agreement with the actual dose, followed by the estimated dose obtained from the regression analysis.

PATIENT-SPECIFIC DOSE ESTIMATES IN DYNAMIC COMPUTED TOMOGRAPHY MYOCARDIAL PERFUSION EXAMINATION.

The study aimed to implement realistic source models of a computed tomography (CT) scanner and Monte Carlo simulations to actual patient data and to calculate patient-specific organ and effective dose estimates for patients undergoing dynamic CT myocardial perfusion examinations. Source models including bowtie filter, tube output and x-ray spectra were determined for a dual-source Siemens Somatom Definition Flash scanner. Twenty CT angiography patient datasets were merged with a scaled International Commission on Radiological Protection (ICRP) 110 voxel phantom. Dose simulations were conducted with ImpactMC software. Effective dose estimates varied from 5.0 to 14.6 mSv for the 80 kV spectrum and from 8.9 to 24.7 mSv for the 100 kV spectrum. Significant differences in organ doses and effective doses between patients emphasise the need to use actual patient data merged with matched anthropomorphic anatomy in the dose simulations to achieve a reasonable level of accuracy in the dose estimation procedure.

137 Cs contaminations in wild-growing medicinal plants of Zhytomyr polissya forests: A 34 years after Chernobyl accident

The contamination of 137Cs in wild-growing medicinal plants was studied with regards to the species, type of forest vegetation conditions and soil specific activity of 137Cs in Zhytomyr polissya forest phytocenoses (Ukraine). The research was carried out in two plots planted in the most region typical edatopes - fresh and wet subor (Querceto-Pinetum). Species composition of phytocenoses was analyzed and the plants that can be harvested for pharmaceutical industry were identified on these test plots,. The herbal substance samples were tested to determine the specific activity of 137Cs. The studies have shown significant variability in the content of radionuclides due to differences in the level of radioactive contamination in the soil and accumulative capacity of plant species. For European blueberry, the peculiarities of 137Cs accumulation in vegetative and generative organs were studied. Comparison of the content of 137Cs in pants of different edatopes showed more higher intensity of radionuclide accumulation in wet suborbs compared to fresh suborbs. The average values of concentration factors were calculated and their rankings were built according to the intensity of 137Cs accumulation for the plants in each edatope. All studied medicinal plants were divided into four groups according to the contration factor: with weak accumulation, moderate accumulation, strong accumulation, and very strong accumulation. Based on the permissible content of 137Cs in wild-growing medicinal plants (600 Bq/kg), the maximum permissible level of soil contamination with radionuclides was determined for each medicinal plant species.

Experience with UNIVU module to reduce X-ray exposure during atrial fibrillation catheter ablation

Catheter ablation (CA) of atrial fibrillation (AF) has become a very common therapy. Considering risks of irradiation exposure, a reduction of fluoroscopy during AF ablation procedures is essential. The UNIVU module, a fluoroscopy image integration module in the CARTO 3 system, aims to reduce irradiation exposure. We sought to evaluate irradiation exposure evolution in our centre during CA of AF since the installation of UNIVU module. Retrospective, monocentric study, including 266 AF catheter ablation (CA) from 01/2016 to 09/2019, with 181 radiofrequency (RF) CA and 85 cryotherapy CA, performed by a single operator. RF procedure performed with CARTO 3 only ( n = 59) were compared to those with CARTO 3 and UNIVU ( n = 122) in terms of fluoroscopy time (FT), dose area product (DAP) and estimated effective dose (ED). The same parameters were collected for cryotherapy procedure during the same period as a comparator. Median FT, DAP and ED were significantly reduced in the “CARTO3 + UNIVU” group compared to the “CARTO 3” group, respectively ( Fig. 1 ). An improvement in the use of the tool resulted in a higher reduction of irradiation in the 2nd year of UNIVU use, to reach a median DAP of 91 cGy.cm 2 [IQ 44–201] and median ED of 0.2mSv [IQ 0.1–0.4] in the “CARTO3 + UNIVU” group ( P < 0.001). In addition, with much higher residual irradiation, the same evolution was observed for cryotherapy procedures, respectively compared before and after UNIVU installation (median FT (12 min [IQ 8.4–15.4] vs. 8.2 min) [IQ 4.5–12.1], P = 0.004), DAP (1000 cGy.cm 2 [IQ 590–1456] vs. 468 cGy.cm 2 [IQ 196–829], P < 0.001) and ED (2 mSv [IQ 1.2–2.9] vs. 0.9 mSv [IQ 0.4–1.7], P < 0.001). The use of the UNIVU module reduces drastically the irradiation during RF ablation procedures of AF.

Estimation of Annual Effective Dose in Namie Town, Fukushima Prefecture due to Inhalation of Radon and Thoron Progeny

Estimation of Annual Effective Dose in Namie Town, Fukushima Prefecture due to Inhalation of Radon and Thoron Progeny

Cumulative diagnostic imaging radiation exposure in premature neonates

To date, there has been limited work evaluating the total cumulative effective radiation dose received by infants in the neonatal intensive care unit. Most previous publications report that the total radiation dose received falls within the safe limits but does not include all types of ionizing radiation studies typically performed on this vulnerable patient population. We aimed to provide an estimate of the cumulative effective ionizing radiation dose (cED) in microSieverts (μSv) received by premature infants ≤32 weeks from diagnostic studies performed throughout their NICU stay, and predictors of exposures. Retrospective chart review from 2004-2011. Data included demographics, gestational age (GA), birth weight (BW), length of stay (LOS), clinical diagnosis, and radiological studies. 1045 charts were reviewed. Median GA = 30.0 weeks (SD 2.7, range 22.0-32.6). Median BW = 1340.0 grams (SD 445.4, range 420-2470). Median number of radiographic studies = 9 (SD 28.5, range 0-210). Median cED = 162μSv (range 0-9248). The cED was positively associated with LOS (p < 0.001) and inversely correlated with GA (p < 0.001) and BW (p < 0.001). Infants with intestinal perforation had the highest median cED 1661μSv compared to 162μSv for others (p < 0.001). Our results provide an estimate of the cumulative effective radiation dose received by premature infants in a level 4 neonatal intensive care unit from all radiological studies involving ionizing radiation and identifies risk factors and predictors of such exposure. Radiation exposure in NICU is highest among the most premature and among infants who suffer from intestinal perforation.

Patient effective dose estimation for routine computed tomography examinations in Iran

Patient effective dose estimation for routine computed tomography examinations in Iran

Conversion factors for effective dose and organ doses with the air Kerma area product in hysterosalpingography.

Histerosalpingography (HSG) remains the dominant diagnostic tool for investigation of infertility in women. Conversion factors used to estimate effective (E) and organ doses (HT) from air Kerma area product (KAP) are needed to estimate patient doses in HSG, performed with state-of-the-art fluoroscopic X-ray systems with digital detectors. In this study, estimates of E and HT for six critical organs/tissues, were derived on an individual basis in 120 HSG procedures and in 1410 irradiation events, performed on two X-ray systems from information available through the radiation dose structured report using Monte Carlo methods. Mean values of E and Hovaries were1.0±0.9mSv and 5.6±5.4mGy. E/KAP conversion factors of 0.13; 0.18; 0.28 and 0.35mSvGy-1cm-2 were established for irradiation events with a Cu filtration of 0.0; 0.1; 0.4 and 0.9mm. A high agreement was obtained between E estimated through Monte Carlo methods and E/KAP conversion factors accounting separately for the different modes of fluoroscopy and the radiography component of HSG, with a systematic error of 0mSv and lower/upper limits of agreement of -0.6 and 0.5mSv. On the contrary, the use of a single coefficient of conversion did not provide accurate estimates of E, showing a bias of -0.4mSv and lower and upper limits of agreement of -1.9 and 1.2mSv. An algorithm for the estimation of effective and organ doses from KAP has been established in HSG procedures depending on the Cu filtration in the X-ray irradiation events.

Estimation of effective dose from CT scanning using dose length product in a Nepalese hospital

Keywords: Effective dose, Dose Length Product, Computed Tomography Dose Indexvolume, Dose Reference Level AbstractAim: The aim of this study was to estimate the effective doses from CT scans using DoseLength Product (DLP) in a Nepalese hospital.Materials and methods: This prospective study was conducted in 150 patients above 18years of age who were referred for CT scan of head, chest and abdomen. The CT scan wasperformed on a 128 slice multi detector scanner. All the subjects who met the inclusioncriteria were included in the study. Following the non-contrast imaging phases of the head,chest and abdomen CTDIvol, DLP, kVp and pitch were recorded for each patient from theconsole display of the scanner. The effective dose was calculated for each examination usingDLP which were graphically analyzed and correlated with the age of the patient.Results: The study showed the mean CTDIvol for head, chest and abdomen to be 53.95±4.83mGy, 5.28±1.17 mGy and 11.15±2.71 mGy respectively along with mean DLP to be923.52±71.11 mGycm, 229.32±48.70 mGycm and 517.02±148.32 mGycm respectively. Usingthese values, the mean effective doses were calculated and found to be 1.93±0.14 mSv,3.20±0.68 mSv and 7.75±2.19 mSv respectively.Conclusion: The calculated effective dose values were lower than in other studies for CTexaminations of chest and abdomen while higher or similar for CT examination of head. Theresults of this survey could motivate other researchers to investigate the radiation doses inother hospitals and help establish national diagnostic reference levels.

Dosimetric Comparison of Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy and Hybrid Three-Dimensional Conformal Radiotherapy/Intensity-Modulated Radiotherapy Techniques for Right Breast Cancer.

This study aimed to compare different types of right breast cancer radiotherapy planning techniques and to estimate the whole-body effective doses and the critical organ absorbed doses. The three planning techniques are intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT; two methods) and hybrid 3D-CRT/IMRT (three-dimensional conformal radiotherapy/intensity-modulated radiotherapy). The VMAT technique includes two methods to deliver a dose: non-continuous partial arc and continuous partial arc. A thermoluminescent dosimeter (TLD) is placed in the RANDO phantom to estimate the organ absorbed dose. Each planning technique applies 50.4 Gy prescription dose and treats critical organs, including the lung and heart. Dose-volume histogram was used to show the planning target volume (V95%), homogeneity index (HI), conformity index (CI), and other optimized indices. The estimation of whole-body effective dose was based on the International Commission on Radiation Protection (ICRP) Publication 60 and 103. The results were as follows: Continuous partial arc and non-continuous partial arc showed the best CI and HI. The heart absorbed doses in the continuous partial arc and hybrid 3D-CRT/IMRT were 0.07 ± 0.01% and 0% (V5% and V10%, respectively). The mean dose of the heart was lowest in hybrid 3D-CRT/IMRT (1.47 Gy ± 0.02). The dose in the left contralateral lung (V5%) was lowest in continuous partial arc (0%). The right ipsilateral lung average dose and V20% are lowest in continuous partial arc. Hybrid 3D-CRT/IMRT has the lowest mean dose to contralateral breast (organs at risk). The whole-body effective doses for ICRP-60 and ICRP-103 were highest in continuous partial arc (2.01 Sv ± 0.23 and 2.89 Sv ± 0.15, respectively). In conclusion, the use of VMAT with continuous arc has a lower risk of radiation pneumonia, while hybrid 3D-CRT/IMRT attain lower secondary malignancy risk and cardiovascular complications.

Estimation of effective dose of propofol mono-sedation for successful insertion of upper gastrointestinal endoscope in healthy, non-obese Chinese adults.

Propofol is effective in sedation for upper gastrointestinal (UGI) endoscopy. However, the optimum dose is ill-defined. This study aimed to estimate the effective dose of propofol mono-sedation for successful endoscope insertion in healthy, non-obese Chinese adults undergoing single UGI endoscopy. Twenty-six adult patients undergoing elective single UGI endoscopy were enrolled in this study. A modified Dixon's up-and-down method was utilized to assess the effective dose of propofol for successful endoscope insertion. The initial dose of propofol administered, 1.6mg/kg, was adjusted with 0.1mg/kg as a step size. The patient's responses to endoscope insertion were classified as either 'movement' or 'no movement'. When patient's responses were changed from 'movement' to 'no movement' or from 'no movement' to 'movement', a crossover was defined. After eight crossovers had been obtained, patient recruitment was stopped. The mean of midpoints of all crossovers obtained by the modified Dixon's up-and-down method in all 26 patients was defined as calculated median effective dose (ED50 ) of propofol for successful endoscope insertion. Furthermore, probit regression analysis was used to determine the dose of propofol where 50% (ED50 ) and 95% (ED95 ) of endoscope insertion attempts were successful. The calculated ED50 of propofol for successful endoscope insertion was 1.89±0.12mg/kg. The probit regression analysis showed that ED50 and ED95 of propofol for successful endoscope insertion were 1.90mg/kg (95% CI, 1.78-2.10mg/kg) and 2.15mg/kg (95% CI, 2.01-3.56mg/kg), respectively. No any patient had hypoxaemia and gag reflex during the UGI endoscopy with propofol mono-sedation. In healthy, non-obese Chinese adults, propofol mono-sedation can provide excellent conditions of UGI endoscopy and the estimated ED50 of propofol for successful endoscope insertion is 1.89±0.12mg/kg.

Factors Affecting Radiation Dose in Computed Tomography Angiograms for Pulmonary Embolism: A Retrospective Cohort Study.

Objectives:Computed tomography pulmonary angiogram (CTPA) is one of the most commonly ordered and frequently overused tests. The purpose of this study was to evaluate the mean radiation dose to patients getting CTPA and to identify factors that are associated with higher dose.Material and Methods:This institutionally approved retrospective study included all patients who had a CTPA to rule out acute pulmonary embolism between 2016 and 2018 in a tertiary care center. Patient data (age, sex, body mass index [BMI], and patient location), CT scanner type, image reconstruction methodology, and radiation dose parameters (dose-length product [DLP]) were recorded. Effective dose estimates were obtained by multiplying DLP by conversion coefficient (0.014 mSv•mGy−1•cm−1). Multivariate logistic regression analysis was performed to determine the factors affecting the radiation dose.Results:There were 2342 patients (1099 men and 1243 women) with a mean age of 58.1 years (range 0.2–104.4 years) and BMI of 31.3 kg/m2 (range 12–91.5 kg/m2). The mean effective radiation dose was 5.512 mSv (median – 4.27 mSv; range 0.1–43.0 mSv). Patient factors, including BMI >25 kg/m2, male sex, age >18 years, and intensive care unit (ICU) location, were associated with significantly higher dose (P < 0.05). CT scanning using third generation dual-source scanner with model-based iterative reconstruction (IR) had significantly lower dose (mean: 4.90 mSv) versus single-source (64-slice) scanner with filtered back projection (mean: 9.29 mSv, P < 0.001).Conclusion:Patients with high BMI and ICU referrals are associated with high CT radiation dose. They are most likely to benefit by scanning on newer generation scanner using advance model-based IR techniques.

A review of dental cone-beam CT dose conversion coefficients.

The purpose of this study was to review the literature to examine the usage and magnitude of effective dose conversion factors (DCE) for dental cone beam CT (CBCT) scanners. A PubMed literature search for publications relating to radiation dosimetry in dental radiography was performed. Papers were included if they reported DCE, or reported ICRP 103 effective dose and dose-area product. 71 papers relating to dental CBCT dosimetry were found, of which eight reported effective dose conversion factors or provided enough information to calculate dose conversion factors. Scanner model, effective dose, dose-area product, tube voltage, field of view size and DCE were extracted from the papers for analysis. DCE values ranged from 0.035 to 0.31 µSv/mGy-cm2 with a mean of 0.129 µSv/mGy-cm2 (SD = 0.056). When categorized into small (<100 cm2), medium (100-225 cm2) and large (>225 cm2) fields of view (FOV), linear fits to the effective dose and dose-area product yielded slopes of 0.129, 0.111 and 0.074 µSv/mGy-cm2 for small, medium and large FOVs respectively. The range of reported DCE values and spread with respect to field of view category suggests that DCE values that depend on FOV would provide more accurate effective dose estimates. Tube voltage was found to be a smaller factor in determining DCE. Reasonable values for DCE taking into account FOV size were obtained. There is considerable room for more work to be done to examine the behaviour of DCE with changes to patient age and dental CBCT imaging parameters.

Patients effective dose estimation during AP pelvis radiography in some hospitals of Al Najaf city, Iraq

Background: Monitoring patients radiation dose during anterior-posterior (AP) pelvis radiography is of paramount importance. This is due to the existence of the gonads within the pelvic region. Objective: The purpose of this work is to estimate effective dose (ED) for adult patients who examined for AP pelvis radiography in the governmental hospitals of Al Najaf city-Iraq. Materials and methods: The ED was estimated for 64 patients (male and female) who undertaking AP pelvis radiography using CALDOSE-X5 Monte Carlo software. The calculation of the ED was based on the measurements of X-ray tube output and the knowledge of exposure factors. The X- ray output was measured using Rad-Check ionization chamber for each X-ray tube. In total, seven X-ray tubes were enrolled to assess the patients’ ED. Exposure factors includes tube potential (kVp), tube loading (mAs) and X-ray source to image detector distance-SID (cm)); these were recorded for each patient together with their demographic data (weight(kg) and height(m)). Five major hospitals were considered in this work (i.e. Al Sadder, Al Hakeem, Al Furat, Al Manzrah and Middel Euphrates cancer center). Results: The average value of the estimated ED was ranged from 0.156±0.041 mSv to 0.4068±0.049 mSv across all hospitals. The value of max/min of the ED was ranged from 1.25 to 2.58 across different hospitals. The corresponding average values of the kVp used for this examination was ranged from 75 to 113.75 kVp; mAs: ranged from 11.7 to 42.1 mAs and for the SID the range was between 100 and 140.6 cm. Conclusion: The resulted data demonstrate there is a clear variability in patient dose and exposure factors set among the selected hospitals. The ED values were seen to be slightly lower than those reported by the UK (Survey-2010, 0.284 mSv) and were higher than those reported by certain countries (e.g. Canada, Ghana etc.). Overall, a periodic checking together with conducting a quality control testing is highly recommended.

Yearly effective dose due to consumption of wild black fungus grow in southern Iraq assessed by measuring of radionuclide concentrations

Wide range of studies have been conducted around the word focusing on the evaluation of radionuclide concentrations in foodstuff. This work focusing on the estimation of the annual effective dose due to radionuclide activity in Iraqi wild fungus, specifically black desert truffles. The fungus have been collected from the desert of As Samawah governorate in the south of Iraq as it is grow in a large amount. The average activity concentrations for 238U, 232Th, 40K and 137Cs were 3.95, 2.53, 260.36 and 1.78 Bqkg −1 respectively in all 10 collected truffle samples. The average annual effective doses from 238U ingestion were 0.36 and 0.54, from 232Th ingestion were 1.16 and 1.47, from 40K ingestion were found to be 3.23 and 319.20 and from 137Cs were 0.05 and 0.04 μSv year−1 in adults and children respectively. The measured values were less than the assessed world mean value from the exposure caused by natural radionuclide ingestion that documented in the literature (0.29 mSv year−1).

Evaluation of the effect of cover layer on radon exhalation from building materials

Radium, which is naturally present in many building materials, decays to the radioactive gas radon, which is exhaled from the surface of concrete block and is a major source of human exposure to radioactivity. In this study, an experimental evaluation of radon exhalation was conducted on a concrete block covered with mortar and acrylic render. Factors such as sand aggregates content and water content of the mortar cover layer, the thickness of the double cover layer were considered. Results showed that the radon exhalation rate was increased with an increase of sand content in mortar cover layer, and the radon exhalation rate was reduced with an increase of the thickness and water content. Besides, indoor radon concentration and effective dose estimation involving concrete block with cover layer were evaluated. The calculated indoor radon concentration was reduced from 234.9 to 201.1 Bq m−3 as the thickness of the cover layer was increased from 15 to 35 mm, and the effective dose was reduced by 0.61 mSv y−1. Therefore, the addition of a cover layer on the indoor walls, floors and ceilings could reduce the indoor radon concentration and the radon dose on exposure to occupants.

Low dose radiation therapy for COVID-19: Effective dose and estimation of cancer risk

Background and purposeThe objective of this work is to evaluate the risk of carcinogenesis of low dose ionizing radiation therapy (LDRT), for treatment of immune-related pneumonia following COVID-19 infection, through the estimation of effective dose and the lifetime attributable risk of cancer (LAR). Material and methodsLDRT treatment was planned in male and female computational phantoms. Equivalent doses in organs were estimated using both treatment planning system calculations and a peripheral dose model (based on ionization chamber measurements). Skin dose was estimated using radiochromic films. Later, effective dose and LAR were calculated following radiation protection procedures. ResultsEquivalent doses to organs per unit of prescription dose range from 10 mSv/cGy to 0.0051 mSv/cGy. Effective doses range from 204 mSv to 426 mSv, for prescription doses ranging from 50 cGy to 100 cGy. Total LAR for a prescription dose of 50 cGy ranges from 1.7 to 0.29% for male and from 4.9 to 0.54% for female, for ages ranging from 20 to 80 years old. ConclusionsThe organs that mainly contribute to risk are lung and breast. Risk for out-of-field organs is low, less than 0.06 cases per 10000. Female LAR is on average 2.2 times that of a male of the same age. Effective doses are of the same order of magnitude as the higher-dose interventional radiology techniques. For a 60 year-old male, LAR is 8 times that from a cardiac CT, when prescription dose is 50 cGy.

Double Dose Reduction in the Equilibrium Phase of Chest-Pelvic CT With Low Tube Voltage and Forward-Projected Model-Based Iterative Reconstruction Solution.

ObjectivesThis study aimed to examine whether a new imaging method (80-kV forward-projected model-based iterative reconstruction solution [FIRST] protocol) that uses a combination of low tube voltage and FIRST can reduce radiation dose and contrast medium volume by comparing the quality of the resulting image with that of the image obtained by 120-kV adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic computed tomography (CT).Subjects and methodsTwenty-seven patients underwent CT by both protocols on different days. Two radiologists subjectively assessed image quality by scoring axial images for sharpness, contrast enhancement, noise, artifacts, and overall quality. The mean CT values, standard deviations, contrast-to-noise ratios, and signal-to-noise ratios in the liver, aorta, and erector spinae muscles were used for objective assessment. Radiation dose parameters included the CT dose index volume, dose-length product, effective dose, and size-specific dose estimate. Results were compared for different body mass index categories.ResultsThe 80-kV FIRST protocol helped achieve mean reductions of 36.3%, 35.7%, and 36.6% in CT dose index volume, effective dose, and size-specific dose estimate, respectively (p < 0.01). Therefore, this protocol was regarded as comparable to the conventional protocol in image quality, except for visual sharpness.ConclusionsThe 80-kV FIRST protocol is capable of reducing radiation dose and contrast medium volume compared to the adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic CT.