SU-E-I-28: Introduction and Investigation of Effective Diameter Ratios as a New Patient Size Metric for Use in CT

2015 ◽  
Vol 42 (6Part6) ◽  
pp. 3247-3248 ◽  
Author(s):  
R Lamoureux ◽  
L Sinclair ◽  
A Mench ◽  
I Lipnharski ◽  
C Carranza ◽  
...  
Keyword(s):  
Effective Diameter ◽  
Patient Size

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 The effective and water-equivalent diameters as geometrical size functions for estimating CT dose in the thoracic, abdominal, and pelvic regions

2021 ◽  
Vol 27 (3) ◽  
pp. 213-222
Author(s):  
Winda Kusuma Dewi ◽  
Choirul Anam ◽  
Eko Hidayanto ◽  
Arrum Nitasari ◽  
Geoff Dougherty
Keyword(s):  
Computed Tomography ◽  
Equivalent Diameter ◽  
Effective Diameter ◽  
Strong Correlations ◽  
Thoracic Region ◽  
Specific Patient ◽  
Geometrical Size ◽  
Ct Dose ◽  
Patient Size ◽  
Anterior Posterior

Abstract Purpose: The aim of this work was to establish the relationships of patient size in terms of effective diameter (Deff) and water-equivalent diameter (Dw) with lateral (LAT) and anterior-posterior (AP) dimensions in order to predict the specific patient dose for thoracic, abdominal, and pelvic computed tomography (CT) examinations. Methods: A total of 47 thoracic images, 79 abdominal images, and 50 pelvic images were analyzed in this study. The patient’s images were retrospectively collected from Dr. Kariadi and Kensaras Hospitals, Semarang, Indonesia. The slices measured were taken from the middle of the scan range. The calculations of patient sizes (LAT, AP, Deff, and Dw) were automatically performed by IndoseCT 20b software. Deff and Dw were plotted as functions of LAT, AP, and AP+LAT. In addition, Dw was plotted as a function of Deff. Results: Strong correlations of Deff and Dw with LAT, AP, and AP+LAT were found. Stronger correlations were found in the Deff curves (R2 > 0.9) than in the Dw curves (R2 > 0.8). It was found that the average Deff was higher than the average Dw in the thoracic region, the average values were similar in the abdominal and pelvic regions. Conclusion: The current study extended the study of the relationships between Deff and Dw and the basic geometric diameter LAT, AP, and AP+LAT beyond those previously reported by AAPM. We evaluated the relationships for three regions, i.e. thoracic, abdominal, and pelvic regions. Based on our findings, it was possible to estimate Deff and Dw from only the LAT or AP dimension.

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 Correlation between age and head diameters in the paediatric patients during CT examination of the head

2019 ◽  
Vol 25 (4) ◽  
pp. 229-235
Author(s):  
Arif Fahmi ◽  
Choirul Anam ◽  
Mohd Hanafi Ali ◽  
Arif Jauhari ◽  
Keyword(s):  
Equivalent Diameter ◽  
Effective Diameter ◽  
Head Ct ◽  
Female Patients ◽  
Ct Examination ◽  
Ct Dose ◽  
Paediatric Patients ◽  
Patient Size ◽  
Ct Head ◽  
Serial Images

Abstract An estimate of patient dose, patient size should be used to normalise the output dose of CT machine in the terms of volume CT dose index, CTDIvol. There are two metrics to characterise the patient size, i.e. the effective diameter (Deff) and the water-equivalent diameter (Dw). These two metrics could be estimated by patient age. However, to date, relationships between the age and head patient size (Deff and Dw) have not been established for the pediatric patients. The aim of this study was to establish the relationships between the age and head patient size (Deff and the Dw) as the basis for calculating the size-specific dose estimate (SSDE) for paediatric head CT examination. The data were retrospectively collected from serial images of the CT head in the DICOM file from one hundred and thirteen paediatric patients aged 0-17 years (63 male and 50 female patients) underwent head CT examinations. The patient’s sizes (Deff and Dw) were calculated from the patient’s images using the IndoseCT version 15a software. The Deff and Dw values were correlated with age of patients using regression analysis. It was found that patient size (Deff and Dw) correlated well with the age of the patient with R2 more than 0.8. The size of the Dw is bigger than the Deff. The Deff values for male patients are 12.38 to 16.21 cm, and Dw values are 11.96 to 18.16 cm, respectively. For female patients, the values of Deff are from 11.54 to 16.87 cm, and the values of Dw are from 11.60 to 17.86 cm, respectively.

Green synthesis, characterization of silver sulfide nanoparticles and antibacterial activity evaluation

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Research Work ◽  
Silver Sulfide ◽  
Morphological Properties ◽  
Effective Diameter ◽  
Novel Approach ◽  
Transmission Electron ◽  
Green Route ◽  
Silver Sulfide Nanoparticles

This research work presents a facile and green route for synthesis silver sulfide (Ag2SNPs) nanoparticles from silver nitrate (AgNO3) and sodium sulfide nonahydrate (Na2S.9H2O) in the presence of rosemary leaves aqueous extract at ambient temperature (27 oC). Structural and morphological properties of Ag2SNPs nanoparticles were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface Plasmon resonance for Ag2SNPs was obtained around 355 nm. Ag2SNPs was spherical in shape with an effective diameter size of 14 nm. Our novel approach represents a promising and effective method to large scale synthesis of eco-friendly antibacterial activity silver sulfide nanoparticles.

scholarly journals A thermophysical and dynamical study of the Hildas (1162) Larissa and (1911) Schubart

2021 ◽  
Author(s):  
Cristian F Chavez ◽  
T G Müller ◽  
J P Marshall ◽  
J Horner ◽  
H Drass ◽  
...  
Keyword(s):  
Thermal Inertia ◽  
Infrared Camera ◽  
Asteroid Belt ◽  
Effective Diameter ◽  
Early Solar System ◽  
Dynamical Study ◽  
Axis Ratio ◽  
Ellipsoidal Shape ◽  
Dynamical Simulations ◽  
Taxonomical Classification

Abstract The Hilda asteroids are among the least studied populations in the asteroid belt, despite their potential importance as markers of Jupiter’s migration in the early Solar system. We present new mid-infrared observations of two notable Hildas, (1162) Larissa and (1911) Schubart, obtained using the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST), and use these to characterise their thermal inertia and physical properties. For (1162) Larissa, we obtain an effective diameter of 46.5$^{+2.3}_{-1.7}$ km, an albedo of 0.12 ± 0.02, and a thermal inertia of 15$^{+10}_{-8}$ Jm−2s1/2K−1. In addition, our Larissa thermal measurements are well matched with an ellipsoidal shape with an axis ratio a/b=1.2 for the most-likely spin properties. Our modelling of (1911) Schubart is not as refined, but the thermal data point towards a high-obliquity spin-pole, with a best-fit a/b=1.3 ellipsoidal shape. This spin-shape solution is yielding a diameter of 72$^{+3}_{-4}$ km, an albedo of 0.039± 0.02, and a thermal inertia below 30 Jm−2s1/2K−1 (or 10$^{+20}_{-5}$ Jm−2s1/2K−1). As with (1162) Larissa, our results suggest that (1911) Schubart is aspherical, and likely elongated in shape. Detailed dynamical simulations of the two Hildas reveal that both exhibit strong dynamical stability, behaviour that suggests that they are primordial, rather than captured objects. The differences in their albedos, along with their divergent taxonomical classification, suggests that despite their common origin, the two have experienced markedly different histories.

scholarly journals In x-ray computed tomography, technique factors should be selected appropriate to patient size

2001 ◽  
Vol 28 (8) ◽  
pp. 1543-1545 ◽  
Author(s):  
Walter Huda ◽  
Stewart C. Bushong ◽  
William R. Hendee
Keyword(s):  
Computed Tomography ◽  
X Ray ◽  
Patient Size ◽  
X Ray Computed
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