scholarly journals Using Age and Weight Specific CT Protocol to Estimate Reference Effective Dose to Patients Undergoing CT Examination

2017 ◽  
pp. 191-196
Author(s):  
Issahaku Shirazu ◽  
Y. B. Mensah ◽  
Cyril Schandorf ◽  
S. Y. Mensah
Keyword(s):  
Effective Dose ◽  
Image Data ◽  
The Body ◽  
Study Patient ◽  
Body Region ◽  
Ct Scanner ◽  
Ct Dose ◽  
Body Regions ◽  
Ct Protocol ◽  
Effective Doses

In x-ray computed tomography (CT), the most common parameters used to estimate and minimize patient dose is the CT dose index (CTDI) and DLP. The aim of the study is to serve as a reference values during QC for the purposes of QA in other to reduce doses to patients undergoing CT scan using the age and weight specific CT protocol set out by various manufacturers and other international organizations. This was done by recording CTDI and DLP values to patients within a specific age and weight bracket during scanning on the scanning console and on image data. The effective dose values represents an averaged dose to patients, hence the measurements are only an approximation of the dose to patient, these doses may be overestimated or underestimated by a factor of two or more with CTDI and DLP values in comparison with point dose values. CTDI and DLP were used to evaluate CT scanner output and estimating patient regional effective dose in this study. The estimated head CTDI scans base on the various protocol from all the hospitals increase from approximately 2.8mGy in newborns to approximately 8.7mGy in adults. Resulting with a variation of effective dose from 0.67mSv in new born to approximately 1.03mSv in oversize adults. Neonates head CT effective doses are higher than those for the normal adults except oversize adults as shown in Table 4.4. The chest, abdominal and pelvis CTDI values increases from 2.8, 2.5 and 2.7 mGy in neonates of approximately 3.4kg of weight to 19.84, 7.78 and 11.33mGy in adults of approximately 72.5kg of weight respectively. The estimated effective doses for neonates undergoing chest, abdomen and pelvis of the body CT were 0.83, 6.7, 4.87 and 5.52mSv, whereas those for normal-sized adults are 13.31, 4.61 and 5.34mSv respectively. Chest oversize patients’ examinations exceeded the recommended dose levels of 19.84mSv whiles the head, abdomen and pelvis were: 1.03, 7.16 and 5.98mSv respectively. It was concluded that patient body doses could be substantially minimized through careful selection of scanning parameters based on clinical indications of study, patient age, body size, and body region being examined. Additional dose reduction to superficial body regions would require the use of shielding materials.

scholarly journals Discovering the forbidden Raman modes at the edges of layered materials

2018 ◽  
Vol 4 (12) ◽  
pp. eaau6252 ◽  
Author(s):  
Yao Guo ◽  
Weixuan Zhang ◽  
Hanchun Wu ◽  
Junfeng Han ◽  
Yongliang Zhang ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Electromagnetic Fields ◽  
Scattered Light ◽  
Layered Materials ◽  
The Body ◽  
Body Region ◽  
Edge Type ◽  
Body Regions ◽  
Raman Modes ◽  
Raman Study

The edges of layered materials have unique properties that substantially differ from the body regions. In this work, we perform a systematic Raman study of the edges of various layered materials (MoS2, WS2, WSe2, PtS2, and black phosphorus). The Raman spectra of the edges feature newly observed forbidden Raman modes, which are originally undetectable from the body region. By selecting the edge type and the polarization directions of the incident and scattered light, all forbidden Raman modes are distinctly detected. Optical simulations show that the edges of layered materials drastically distort the electromagnetic fields of both the incident and scattered light, so that the light interacts with the edges in a distinct way, which differs from its interactions with the body regions.

CT dosimetry at the Australian Synchrotron for 25–100 keV photons and 35–160 mm-diameter biological specimens

2019 ◽  
Vol 26 (2) ◽  
pp. 517-527
Author(s):  
Stewart Midgley ◽  
Nanette Schleich ◽  
Alex Merchant ◽  
Andrew Stevenson
Keyword(s):  
Effective Dose ◽  
Beam Quality ◽  
Absorbed Dose ◽  
Body Region ◽  
Average Dose ◽  
Dose Length Product ◽  
Organ Doses ◽  
Ct Dose ◽  
Radiation Output ◽  
Ct Dosimetry

The dose length product (DLP) method for medical computed tomography (CT) dosimetry is applied on the Australian Synchrotron Imaging and Medical Beamline (IMBL). Beam quality is assessed from copper transmission measurements using image receptors, finding near 100% (20 keV), 3.3% (25 keV) and 0.5% (30–40 keV) relative contributions from third-harmonic radiation. The flat-panel-array medical image receptor is found to have a non-linear dose response curve. The amount of radiation delivered during an axial CT scan is measured as the dose in air alone, and inside cylindrical PMMA phantoms with diameters 35–160 mm for mono-energetic radiation 25–100 keV. The radiation output rate for the IMBL is comparable with that used for medical CT. Results are presented as the ratios of CT dose indices (CTDI) inside phantoms to in air with no phantom. Ratios are compared for the IMBL against medical CT where bow-tie filters shape the beam profile to reduce the absorbed dose to surface organs. CTDI ratios scale measurements in air to estimate the volumetric CTDI representing the average dose per unit length, and the dose length product representing the absorbed dose to the scanned volume. Medical CT dose calculators use the DLP, beam quality, axial collimation and helical pitch to estimate organ doses and the effective dose. The effective dose per unit DLP for medical CT is presented as a function of body region, beam energy and sample sizes from neonate to adult.

Should registrars be reporting after-hours CT scans? A calculation of error rate and the influencing factors in South Africa

2012 ◽  
Vol 53 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Owen D Terreblanche ◽  
Savvas Andronikou ◽  
Linda T Hlabangana ◽  
Taryn Brown ◽  
Pieter E Boshoff
Keyword(s):  
South Africa ◽  
Influencing Factors ◽  
Error Rate ◽  
The Body ◽  
Ct Scans ◽  
Body Region ◽  
Body Regions ◽  
Significant Difference ◽  
After Hours ◽  
The Difference

Background There is a heavy reliance on registrars for after-hours CT reporting with a resultant unavoidable error rate. Purpose To determine the after-hours CT reporting error rate by radiology registrars and influencing factors on this error rate. Material and Methods A 2-month prospective study was undertaken at two tertiary, level 1 trauma centers in Johannesburg, South Africa. Provisional CT reports issued by the registrar on call were reviewed by a qualified radiologist the following morning and information relating to the number, time and type of reporting errors made as well as the body region scanned, indication for the scan, year of training of the registrar, and workload during the call were recorded and analyzed. Results A total of 1477 CT scans were performed with an overall error rate of 17.1% and a major error rate of 7.7%. The error rate for 2nd, 3rd, and 4th year registrars was 19.4%, 15.1%, and 14.5%, respectively. A significant difference was found between the error rate in reporting trauma scans (15.8%) compared to non-trauma scans (19.2%) although the difference between emergency scans (16.9%) and elective scans (22.6%) was found to be not significant, a finding likely due to the low number of elective scans performed. Abdominopelvic scans elicited the highest number of errors (33.9%) compared to the other body regions such as head (16.5%) and cervical, thoracic, or lumbar spine (11.7%). Increasing workload resulted in a significant increase in error rate when analyzed with a generalized linear model. There was also a significant difference noted in the time of scan groups which we attributed to a workload effect. Missed findings were the most frequent errors seen (57.3%). Conclusion We found an increasing error rate associated with increasing workload and marked increase in errors with the reporting of abdominopelvic scans. There was a decrease in the error rate when looking an increasing year of training although this there was only found to be significant difference between the 2nd and 3rd year registrars.

Repeatability of an Exposure Assessment Method for Job Rotation

2005 ◽  
Vol 49 (14) ◽  
pp. 1380-1384
Author(s):  
Susan Kotowski ◽  
Kermit Davis ◽  
Michael Jorgensen
Keyword(s):  
Intervention Strategy ◽  
Assessment Method ◽  
The Body ◽  
Body Region ◽  
Analysis Method ◽  
Easy Method ◽  
Job Rotation ◽  
Body Regions ◽  
Rotation Scheme ◽  
Assessment Techniques

As job rotation has become a widely used intervention strategy for the prevention of a wide variety of musculoskeletal disorders, there is a need for the development of assessment techniques that take into account the complexities of multiple body region stressors. The current study investigates the repeatability of a video-based analysis method that combines the exposure measure of four body regions: neck, shoulder, low back, and hand/wrist. Twelve analysts completed the assessment twice for 15 different job rotation schemes. The repeatability was found to be strong (ICC > 0.53) in many of the body regions when individual jobs were evaluated with minimal decrease in repeatability when the entire rotation scheme was considered. Overall, the video-based method provides a potential quick and easy method that will allow for the versatile evaluation needed for practitioners when quantifying exposure for job rotation schemes.

scholarly journals Influence of Different Arm Positions in the Localizer Radiograph(s) on Patient Dose during Exposure-Controlled CT Examinations of the Neck to Pelvis

Tomography ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 313-322
Author(s):  
Tony M. Svahn ◽  
Lovre Peric ◽  
Jennifer C. Ast
Keyword(s):  
Computed Tomography ◽  
Monte Carlo ◽  
Effective Dose ◽  
Patient Dose ◽  
Whole Body ◽  
Ct Scanner ◽  
Effective Doses ◽  
The Impact ◽  
Total Effective Dose

Our aim was to examine the impact of different arm positions during imaging of the localizer radiograph(s) on effective dose for exposure-controlled computed tomography (CT) (Siemens/Canon) scans of the neck to pelvis. An anthropomorphic whole-body phantom was scanned from the neck to pelvis with the arms positioned in three different ways during the acquisition of the localizer radiograph: (i) above the head, (ii) alongside the trunk, and (iii) along the trunk with the hands placed on the abdomen. In accordance with clinical routines, the arms were not included in the subsequent helical scans. Effective doses were computed to a standard-sized patient (male/female) using a dedicated system-specific Monte Carlo-based software. Effective doses for the Canon CT scanner for the different alternatives (male/female) were (a) 5.3/6.62 mSv, (b) 5.62/7.15 mSv and (c) 5.92/7.44 mSv. For the Siemens CT scanner, effective doses were (a) 4.47/5.59 mSv, (b) 5.4/6.69 mSv and (c) 5.7/6.99 mSv. Arms placed above the head during localizer radiograph imaging in the current CT procedures substantially reduced the total effective dose to the patient.

scholarly journals Myogenesis of Siboglinum fiordicum sheds light on body regionalisation in beard worms (Siboglinidae, Annelida)

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Nadezhda Rimskaya-Korsakova ◽  
Nadezda Karaseva ◽  
Timofei Pimenov ◽  
Hans Tore Rapp ◽  
Eve Southward ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
The Body ◽  
Body Region ◽  
Competent Larva ◽  
Body Regions ◽  
Transmission Electron ◽  
Chaetopterus Variopedatus ◽  
Mode Of Life ◽  
Anterior Body

Abstract Background Many annelids, including well-studied species such as Platynereis, show similar structured segments along their body axis (homonomous segmentation). However, numerous annelid species diverge from this pattern and exhibit specialised segments or body regions (heteronomous segmentation). Recent phylogenomic studies and paleontological findings suggest that a heteronomous body architecture may represent an ancestral condition in Annelida. To better understand the segmentation within heteronomous species we describe the myogenesis and mesodermal delineation of segments in Siboglinum fiordicum during development. Results Employing confocal and transmission electron microscopy we show that the somatic longitudinal musculature consists of four separate strands, among which ventrolateral one is the most prominent and is proposed to drive the search movements of the head of the late metatrochophore. The somatic circular musculature lies inside the longitudinal musculature and is predominantly developed at the anterior end of the competent larva to support the burrowing behaviour. Our application of transmission electron microscopy allows us to describe the developmental order of the non-muscular septa. The first septum to form is supported by thick bundles of longitudinal muscles and separates the body into an anterior and a posterior region. The second group of septa to develop further divides the posterior body region (opisthosoma) and is supported by developing circular muscles. At the late larval stage, a septum reinforced by circular muscles divides the anterior body region into a forepart and a trunk segment. The remaining septa and their circular muscles form one by one at the very posterior end of the opisthosoma. Conclusions The heteronomous Siboglinum lacks the strict anterior to posterior sequence of segment formation as it is found in the most studied annelid species. Instead, the first septum divides the body into two body regions before segments are laid down in first the posterior opisthosoma and then in the anterior body, respectively. Similar patterns of segment formation are described for the heteronomous chaetopterid Chaetopterus variopedatus and serpulid Hydroides elegans and may represent an adaptation of these annelids to the settlement and transition to the sedentarian-tubiculous mode of life.

scholarly journals Myogenesis of Siboglinum Fiordicum Sheds Light on Body Regionalisation in Beard Worms (Siboglinidae, Annelida)

2021 ◽  
Author(s):  
Nadezhda Nikolaevna Rimskaya-Korsakova ◽  
Nadezda Karaseva ◽  
Timofei Pimenov ◽  
Hans Tore Rapp ◽  
Eve Southward ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
The Body ◽  
Body Region ◽  
Body Regions ◽  
Transmission Electron ◽  
Chaetopterus Variopedatus ◽  
Anterior Body ◽  
Longitudinal Muscles ◽  
Posterior Body Region

Abstract BackgroundMany annelids, including well-studied species such as Platynereis, show similar structured segments along their body axis (homonomous segmentation). However, numerous annelid species diverge from this pattern and exhibit specialised segments or body regions (heteronomous segmentation). Recent phylogenomic studies and paleontological findings suggest that a heteronomous body architecture may represent an ancestral condition in Annelida. To better understand the segmentation within heteronomous species we describe the myogenesis and mesodermal delineation of segments in Siboglinum fiordicum during development. ResultsEmploying confocal and transmission electron microscopy we show that the somatic circular musculature lies inside the longitudinal musculature and is predominantly developed at the anterior end of the larva. The longitudinal musculature consists of four separate strands at the ventral, dorsal, and ventrolateral body sides. Posteriorly, the longitudinal strands form a continuous layer. Our application of transmission electron microscopy allows us to describe the developmental order of the non-muscular septa. The first septum to form is supported by thick bundles of longitudinal muscles and separates the body into an anterior and a posterior region. The second group of septa to develop further divides the posterior body region (opisthosoma) and is supported by developing circular muscles. At the late larval stage, a septum reinforced by circular muscles divides the anterior body region into a forepart and a trunk segment. The remaining septa and their circular muscles form one by one at the very posterior end of the opisthosoma. Functionally, the prominent ventrolateral longitudinal muscles in the larva are proposed to drive the search movements of the head, while the anterior circular muscles and the posterior continuous layers of longitudinal muscles support the burrowing behaviour of the larva.ConclusionsThe heteronomous Siboglinum lacks the strict anterior to posterior sequence of segment formation as it is found in the most studied annelid species. Instead, the first septum divides the body into two body regions, before segments are layed down in first the posterior opisthosoma and then in the anterior body, respectively. Similar pattern of segment formation is described for the heteronomous chaetopterid Chaetopterus variopedatus and may represent an ancestral segmentation process in Annelida.

scholarly journals Development of CT Effective Dose Conversion Factors from Clinical CT Examinations in the Republic of Korea

Diagnostics ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 727
Author(s):  
Sang-Kyung Lee ◽  
Jung Su Kim ◽  
Sang-Wook Yoon ◽  
Jung Min Kim
Keyword(s):  
Effective Dose ◽  
Nationwide Survey ◽  
Adult Brain ◽  
Radiological Protection ◽  
Dose Length Product ◽  
Conversion Factors ◽  
Ct Dose ◽  
Ct Protocol ◽  
Ct Data ◽  
The Republic

The aim of this study was to determine the conversion factors for the effective dose (ED) per dose length product (DLP) for various computed tomography (CT) protocols based on the 2007 recommendations of the International Commission on Radiological Protection (ICRP). CT dose data from 369 CT scanners and 13,625 patients were collected through a nationwide survey. Data from 3793 patients with a difference in height within 5% of computational human phantoms were selected to calculate ED and DLP. The anatomical CT scan ranges for 11 scan protocols (adult-10, pediatric-1) were determined by experts, and scan lengths were obtained by matching scan ranges to computational phantoms. ED and DLP were calculated using the NCICT program. For each CT protocol, ED/DLP conversion factors were calculated from ED and DLP. Estimated ED conversion factors were 0.00172, 0.00751, 0.00858, 0.01843, 0.01103, 0.02532, 0.01794, 0.02811, 0.02815, 0.02175, 0.00626, 0.00458, 0.00308, and 0.00233 mSv∙mGy−1∙cm−1 for the adult brain, intra-cranial angiography, C-spine, L-spine, neck, chest, abdomen and pelvis, coronary angiography, calcium scoring, aortography, and CT examinations of pediatric brain of <2 years, 4–6 years, 9–11 years, and 13–15 years, respectively. We determined ED conversion factors for 11 CT protocols using CT data obtained from a nationwide survey in Korea and Monte Carlo-based dose calculations.

scholarly journals Timing of surgical intervention for compartment syndrome in different body region: systematic review of the literature

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Federico Coccolini ◽  
Mario Improta ◽  
Edoardo Picetti ◽  
Luigi Branca Vergano ◽  
Fausto Catena ◽  
...  
Keyword(s):  
Compartment Syndrome ◽  
Surgical Intervention ◽  
Clinical Signs ◽  
The Body ◽  
Body Region ◽  
Many Body ◽  
Patient Death ◽  
Body Regions ◽  
Time Burden ◽  
Life Threatening

AbstractCompartment syndrome can occur in many body regions and may range from homeostasis asymptomatic alterations to severe, life-threatening conditions. Surgical intervention to decompress affected organs or area of the body is often the only effective treatment, although evidences to assess the best timing of intervention are lacking. Present paper systematically reviewed the literature stratifying timings according to the compartmental syndromes which may beneficiate from immediate, early, delayed, or prophylactic surgical decompression. Timing of decompression have been stratified into four categories: (1) immediate decompression for those compartmental syndromes whose missed therapy would rapidly lead to patient death or extreme disability, (2) early decompression with the time burden of 3–12 h and in any case before clinical signs of irreversible deterioration, (3) delayed decompression identified with decompression performed after 12 h or after signs of clinical deterioration has occurred, and (4) prophylactic decompression in those situations where high incidence of compartment syndrome is expected after a specific causative event.

scholarly journals Measurement of radiation dose in multi-slice computed tomography

2016 ◽  
Vol 9 (4) ◽  
pp. 196
Author(s):  
Surendra Maharjan ◽  
Sudil Prajapati ◽  
Om Biju Panta
Keyword(s):  
Computed Tomography ◽  
Effective Dose ◽  
Standard Dose ◽  
Reference Dose ◽  
International Reference ◽  
Ct Dose ◽  
Abdomen Ct ◽  
Standard Patient ◽  
Effective Doses ◽  
Dose Levels

<p>The aim of this study was to measure the radiation doses for computed tomography (CT) examinations of the head, chest and abdomen in adult patients in Nepal in comparison to international standard. Dose length products (DLP) and effective doses for standard patient sizes were calculated from the reported volume CT dose index (CTDI<sub>Vol</sub>). Details were obtained from approximately 90 CT examinations carried out in 128 slice CT scan. Effective dose was calculated for each examination using CT dose indices, exposure related parameters and CTDI-to-effective dose conversion factors. The CTDI and DLP were below the established international reference dose levels for head and chest while for the abdomen and pelvis, the CTDl and DLP were above the established international reference dose levels. The mean effective doses in this study for the head, chest, and abdomen were 1.7, 5.4 and 17.7 mGy respectively. In conclusion, for the routine head and chest protocol, CTDI, DLP and ED were found to be significantly lower compared to the recommendation of European Commission. However, abdomen CT scans showed higher dose values because of multiple phase scans and longer scan lengths.</p>

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