scholarly journals Optimization of Dose Parameters to Patients Undergoing CT Scan Using Four Different CT Scanners with International Guidelines

2017 ◽  
pp. 197-203
Author(s):  
Issahaku Shirazu ◽  
Y. B Mensah ◽  
Cyril Schandorf ◽  
S. Y. Mensah ◽  
Alfred Owusu
Keyword(s):  
Ct Scan ◽  
Medical Diagnosis ◽  
Image Data ◽  
Ct Scanning ◽  
Radiation Doses ◽  
Ct Scanner ◽  
Additional Source ◽  
Scanning Protocol ◽  
Ct Scanners ◽  
Radiological Procedures

Although the use of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures, lack of proper optimized protocols could be an additional source of increased dose in developing countries. The aims of this study is to determine the variations of doses to patients undergoing CT scan using four different CT scanners with different CT scanning protocols for the purposes of optimizations and to compare with other available international standard and guidelines. The method involve the use of patients scanning protocol and image data to estimate patient body regional doses with four common CT examinations. These were obtained from four CT units/hospitals in Ghana. A large variation of mean body regional doses among different CT scanners were observed for similar CT examinations. These variations largely originated from different CT scanning protocols used, with different CT scanner type. The measured CTDIVOL with GE Lightspeed VCT 64 scanner for head, hest, abdomen and pelvis were 7.7mGy, 12.5 mGy, 14.4 mGy, and 12.9 mGy, respectively. Similarly, Philip 16 scanner recorded 6.6mGy, 13.1mGy, 14.8mGy, and 14.5mGy respectively. Furthermore, Siemen Emotion 16 scanner recorded 5.9mGy, 14.2mGy, 16.8mGy and 12.0mGy respectively. While, Toshiba Aquilion one scanner had CTDIVOL value which varies as 7.2mGy, 13.4mGy, 15.2mGy and 13.5mGy respectively. In conclusion the values were mostly lower than the values of CTDI and DLP as reported in literature for EC, IAEA, ICRP, ACR and AAPM Guidelines.

Preliminary experience with Brown-Roberts-Wells (BRW) computerized tomography stereotaxic guidance system

1983 ◽  
Vol 59 (2) ◽  
pp. 217-222 ◽  
Author(s):  
M. Peter Heilbrun ◽  
Theodore S. Roberts ◽  
Michael L. J. Apuzzo ◽  
Trent H. Wells ◽  
James K. Sabshin
Keyword(s):  
Ct Scan ◽  
Computerized Tomography ◽  
Guidance System ◽  
Production Model ◽  
Ct Scanner ◽  
Content Type ◽  
Ct Scanners ◽  
Guidance Systems ◽  
Fine Print

✓ The production model of the Brown-Roberts-Wells (BRW) computerized tomography (CT) stereotaxic guidance system is described. Hardware and software modifications to the original prototype now allow the system to be used independently of the CT scanner after an initial scan with the localizing components fixed to the skull. The system is simple and efficient, can be used universally with all CT scanners, and includes a phantom simulator system for target verification. Preliminary experience with 74 patients at two institutions is described. It is concluded that CT stereotaxic guidance systems will become important tools in the neurosurgical armamentarium, as they allow accurate approach to any target identifiable on the CT scan.

Traumatically Induced Brain Stem Hemorrhage and the Computerized Tomographic Scan

Neurosurgery ◽  
1979 ◽  
Vol 4 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Paul R. Cooper ◽  
Kenneth Maravilla ◽  
Joel Kirkpatrick ◽  
Sarah F. Moody ◽  
Frederick H. Sklar ◽  
...  
Keyword(s):  
Ct Scan ◽  
Brain Stem ◽  
Thin Section ◽  
Ex Vivo ◽  
Ct Scanning ◽  
Volume Effect ◽  
Brain Parenchyma ◽  
Ct Scanner ◽  
Cross Sectional ◽  
The Brain

Abstract The computerized tomographic (CT) scan has revolutionized the management of cerebral trauma. Nevertheless, visualization of traumatically induced lesions of the brain stem by the CT scanner remains difficult. Seven patients with autopsy or CT evidence of brain stem hemorrhage were identified over a 1-year period. In six of these patients, brain stem hemorrhage could be defined by CT scan. As part of a prospective study of CT changes after head injury, we performed serial CT scans on six of the seven patients. Clinical experience shows that timing is important for identification of these lesions and that inability to visualize brain stem hematomas may occur because of the development of hematomas after CT scanning, evolution of hemorrhagic lesions that makes them isodense with the surrounding brain stem, patient movement, and technical factors such as the partial volume effect. Experimental injection of fresh blood into the pons and midbrain of cadavers shows that lesions as small as 0.1 ml in volume may be visualized by ex vivo thin section CT scanning techniques. However, the character and anatomical configuration of the hemorrhage may be as important in determining CT visualization as is the volume of the hemorrhage. For example, a hematoma displacing the brain parenchyma was visualized, but a similar-sized small hemorrhage that had diffused through the brain stem tissues was not. Although many of the experimentally placed lesions extended over a rostral-caudal length of 15 mm or more in the brain stem, no lesion was seen on more than three thin section scans. This is explained by the presence of lesions that, although extensive in a rostral-caudal direction, had relatively small cross sectional areas available for identification by the CT scanner. The small size of traumatic lesions of the brain stem and their proximity to bony structures at the base of the skull are not insurmountable obstacles to visualization of brain stem hemorrhages. Serial scanning and the application of thin section computed tomography will lead to identification of most of these lesions.

scholarly journals Diagnosis of diaphragm injuries using modern 256-slice CT scanners: too early to abandon operative exploration

2018 ◽  
Vol 3 (1) ◽  
pp. e000251
Author(s):  
Rindi Uhlich ◽  
Jeffrey David Kerby ◽  
Patrick Bosarge ◽  
Parker Hu
Keyword(s):  
Diagnostic Accuracy ◽  
Ct Scan ◽  
Multidetector Ct ◽  
Trauma Patients ◽  
Ct Scanner ◽  
Level Of Evidence ◽  
Diaphragm Injury ◽  
Hernia Formation ◽  
Operative Exploration ◽  
Ct Scanners

BackgroundMissed injury of the diaphragm may result in hernia formation, enteric strangulation, and death. Compounding the problem, diaphragmatic injuries are rare and difficult to diagnose with standard imaging. As such, for patients with high suspicion of injury, operative exploration remains the gold standard for diagnosis. As no current data currently exist, we sought to perform a pragmatic evaluation of the diagnostic ability of 256-slice multidetector CT scanners for diagnosing diaphragmatic injuries after trauma.MethodsA retrospective review of trauma patients from 2011 to 2018 was performed at an American College of Surgeons-verified level 1 trauma center to identify the diagnostic accuracy of CT scan for acute diaphragm injury. All patients undergoing abdominal operation were eligible for inclusion. Two separate levels of CT scan technology, 64-slice and 256-slice, were used during this time period. The prospective imaging reports were reviewed for the diagnosis of diaphragm injury and the results confirmed with the operative record. Injuries were graded using operative description per the American Association for the Surgery of Trauma guidelines.ResultsOne thousand and sixty-eight patients underwent operation after preoperative CT scan. Acute diaphragm injury was identified intraoperatively in 14.7%. Most with diaphragmatic injury underwent 64-slice CT (134 of 157, 85.4%). Comparing patients receiving 64-slice or 256-slice CT scan, there was no difference in the side of injury (left side 57.5% vs. 69.6%, p=0.43) or median injury grade (3 (3, 3) vs. 3 (2, 3), p=0.65). Overall sensitivity, specificity, and diagnostic accuracy of the 256-slice CT were similar to the 64-slice CT (56.5% vs. 45.5%, 93.7% vs. 98.1%, and 89.0% vs. 90.2%).DiscussionThe new 256-slice multidetector CT scanner fails to sufficiently improve diagnostic accuracy over the previous technology. Patients with suspicion of diaphragm injury should undergo operative intervention.Level of evidenceI, diagnostic test or criteria.

StyroStone: A protocol for scanning and extracting three-dimensional meshes of stone artefacts using Micro-CT scanners v1

2021 ◽  
Author(s):  
Dominik Göldner ◽  
Fotios Alexandros Karakostis ◽  
Armando Falcucci
Keyword(s):  
Three Dimensional ◽  
Computation Time ◽  
Ct Scanning ◽  
3D Models ◽  
Stone Tools ◽  
Surface Model ◽  
Micro Ct ◽  
Ct Scanner ◽  
Micro Computed Tomography ◽  
Ct Scanners

This protocol presents the first detailed step-by-step pipeline for the 3D scanning and post processing of large batches of lithic artefacts using a micro-computed tomography (micro-CT) scanner (i.e., a Phoenix v-tome-x S model by General Electronics MCC, Boston MA) and an Artec Space Spider scanner (Artec Inc., Luxembourg). This protocol was used to scan and analyze ca. 700 lithic artefacts from the Protoaurignacian layers at Fumane Cave in north-eastern Italy (Falcucci et al., in preparation). For this study several costly scanners and proprietary software packages were employed. Although it is not easy to find a low-budget alternative for the scanners, it is possible to use free and open-source software programs, such as 3D-Slicer (https://www.slicer.org/) or MorphoDig (https://morphomuseum.com/morphodig), to process CT data as well as MeshLab (Cignoni et al. 2008) to interact with the 3D models in general. However, if alternative software is used, the steps and their order described in this protocol might diverge significantly. A cost-effective alternative to create 3D models is digital photogrammetry using commercial cameras and freely available software like Meshroom (https://alicevision.org). Although photogrammetry is an affordable technique to create accurate 3D models of objects, this method might not be useful when scanning large batches of artefacts, as it will require a lot of computation time and processing capacity. Likewise, it could be difficult to generate accurate 3D models of very small and/or detailed tool shapes using 3D surface scanners because stone tools are often much smaller than the recommended minimum field of view. Similarly, the resolution of conventional medical CT scanners might not be sufficient to capture minor details of stone tools, such as the outline or dorsal scars. Thus, high-resolution micro-CT technology is the only reliable way to accurately capture the overall morphology of small stone tools. This protocol aims at providing the first detailed procedure dedicated to the scanning of small lithic implements for further three-dimensional analysis. Note that some of the steps must be repeated at different working stages throughout this protocol. In cases where a task must be done in the exact same way as described in a previous step, a reference to that step is provided. When slight changes were made, the step was modified and reported entirely. This protocol contains a few red and green colours (e.g., arrows or within-program colours) which might be perceived differently by people with dyschromatopsia. However, the display of these colours has been kept to a minimum. We recommend the reader to go over the entire protocol carefully, even if only some specific parts are required. A few points are in fact interdependent, and some of them must be applied simultaneously. Content: Part 1 – Styrofoam preparation Part 2 – Micro-CT scanning Part 3 – 3D model extraction of CT scanned stone artifacts using Avizo Part 4 – Cropping extracted surface model to separate Face A and B in Artec Studio Part 5 – Cropping Face A to separate the lines in Artec Studio Part 6 – Cropping each stone artefact from the lines in Artec Studio Part 7 – Virtually control measurements in MeshLab Part 8 – Artec scanning of larger artifacts Part 9 – Export meshes as non-binary ply models for successive analysis in geomorph Three-dimensional example (in ply format) of the effectivity of the StyroStone Protocol: You can download an example of one Styrofoam line in 3D obtained using our protocol to appreciate the result that can be achieved. We have selected a line where objects are characterized by different metric and morphological attributes. Notice the retouching well visible in the last five smaller artifacts (counting from the left when artifact are oriented with the dorsal face in front of the observer and the butt down), as well as the platforms and bulbs of all artifacts. For more information and examples, feel free to contact us!

SU-FF-J-27: Novel 4D CT Scanning Protocol Using a Helical Single-Slice CT Scanner

2005 ◽  
Vol 32 (6Part4) ◽  
pp. 1925-1925
Author(s):  
G Stroian ◽  
E Heath ◽  
L Collins ◽  
J Seuntjens
Keyword(s):  
Ct Scanning ◽  
Ct Scanner ◽  
4D Ct ◽  
Scanning Protocol ◽  
Single Slice

scholarly journals Radiation dose from CT scanning: can it be reduced?

2011 ◽  
Vol 5 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Panruethai Trinavarat ◽  
Supika Kritsaneepaiboon ◽  
Chantima Rongviriyapanich ◽  
Pannee Visrutaratna ◽  
Jiraporn Srinakarin
Keyword(s):  
Radiation Dose ◽  
Ct Scan ◽  
Ct Scanning ◽  
Basic Knowledge ◽  
Radiation Doses ◽  
University Hospitals ◽  
Lifetime Cancer Risk ◽  
Ct Dose ◽  
Ct Radiation ◽  
Probability Of Cancer

Abstract CT has been used to save many patients’ lives and the demand for CT is still increasing. At the same time, there has been increasing concern of the probability of cancer induction by CT radiation. It is necessary for everyone involved in CT scanning, particularly physicians who have to communicate with patients when planning a CT scan, to have a basic knowledge of the CT radiation dose and its potential adverse effects. We have undertaken a systematic review of the literatures to document the radiation dose from CT, the lifetime cancer risk from CT exposure, CT dose parameters, the internationnal CT diagnostic reference levels, and the use and limitation of the CT effective dose. In addition, we conducted a brief survey of the use of CT scan in some university hospitals in Thailand and estimated current CT doses at these hospitals. Our review and survey suggests that CT scanning provides a great benefit in medicine but it also becomes the major source of X-ray exposure. Radiation doses from a CT scan are much higher than most conventional radiographic procedures. This raises concerns about the carcinogenic potentials. We encourage every CT unit to adhere to the International Guidelines of CT dose parameter references. Our preliminary survey from some university hospitals in Thailand revealed that CT radiation doses are within acceptable standard ranges. However, the justification for utilization of CT scans should also be required and monitored. The importance of adequate communication between attending physician and consulting radiologist is stressed.

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

2020 ◽  
Vol 6 (1) ◽  
pp. 56-63
Author(s):  
Pooja Shah
Keyword(s):  
Ct Scan ◽  
Effective Dose ◽  
Ct Scanning ◽  
Reference Level ◽  
Radiation Doses ◽  
Reference Levels ◽  
Contrast Imaging ◽  
Dose Length Product ◽  
Effective Doses ◽  
The Mean

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.  

Reliability of left and right indicators in CT scanning of the head

1987 ◽  
Vol 67 (2) ◽  
pp. 291-292 ◽  
Author(s):  
Alfred J. Luessenhop ◽  
Dieter Schellinger
Keyword(s):  
Ct Scan ◽  
Computerized Tomography ◽  
Patient Positioning ◽  
Ct Scanning ◽  
Ct Scanner ◽  
Content Type ◽  
Normal Side ◽  
Present Generation ◽  
Left And Right ◽  
Fine Print

✓ A case is described in which incorrect preliminary programming of a computerized tomography (CT) machine caused transposition of the left- and right-side indicators in a CT scan, which led to craniotomy on the normal side. The possible mechanism for this is incorrect pre-scan programming of the CT scanner with respect to patient positioning in the scanner gantry. This error, although unlikely, is still possible with the present generation of CT scanners.

scholarly journals Image Registration of 18F-FDG PET/CT Using the MotionFree Algorithm and CT Protocols through Phantom Study and Clinical Evaluation

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 669
Author(s):  
Deok-Hwan Kim ◽  
Eun-Hye Yoo ◽  
Ui-Seong Hong ◽  
Jun-Hyeok Kim ◽  
Young-Heon Ko ◽  
...  
Keyword(s):  
Ct Scan ◽  
Ct Scanning ◽  
Motion Artifacts ◽  
Scanning Time ◽  
Pet Ct ◽  
Static Images ◽  
Type C ◽  
Natural Breathing ◽  
Fdg Pet Ct ◽  
Patient Studies

We evaluated the benefits of the MotionFree algorithm through phantom and patient studies. The various sizes of phantom and vacuum vials were linked to RPM moving with or without MotionFree application. A total of 600 patients were divided into six groups by breathing protocols and CT scanning time. Breathing protocols were applied as follows: (a) patients who underwent scanning without any breathing instructions; (b) patients who were instructed to hold their breath after expiration during CT scan; and (c) patients who were instructed to breathe naturally. The length of PET/CT misregistration was measured and we defined the misregistration when it exceeded 10 mm. In the phantom tests, the images produced by the MotionFree algorithm were observed to have excellent agreement with static images. There were significant differences in PET/CT misregistration according to CT scanning time and each breathing protocol. When applying the type (c) protocol, decreasing the CT scanning time significantly reduced the frequency and length of misregistrations (p < 0.05). The MotionFree application is able to correct respiratory motion artifacts and to accurately quantify lesions. The shorter time of CT scan can reduce the frequency, and the natural breathing protocol also decreases the lengths of misregistrations.

Selective non-operative management of anterior abdominal stab wounds with emphasis on the value of follow-up abdominal CT scanning

Trauma ◽  
2017 ◽  
Vol 20 (3) ◽  
pp. 194-202
Author(s):  
El Yamani Fouda ◽  
Alaa Magdy ◽  
Sameh Hany Emile
Keyword(s):  
Ct Scan ◽  
Ct Scanning ◽  
Operative Management ◽  
Abdominal Ct ◽  
Management Group ◽  
Abdominal Ct Scan ◽  
Laparotomy Group ◽  
Abdominal Stab Wounds ◽  
Non Operative Management

Background and aim Selective non-operative management of patients with penetrating abdominal stabs is the preferred treatment strategy. The present study aimed to assess the efficacy and safety of non-operative management with emphasis on the value of follow-up abdominal CT scanning in management of patients with penetrating anterior abdominal stab. Patients and methods This is a retrospective chart review of stable patients with anterior abdominal stab wounds. Patients were divided in terms of initial decisions into two groups: laparotomy group and non-operative management group. Abdominal CT scan was performed for patients in the non-operative management group on admission and follow-up CT scanning was performed in cases of clinical and/or biochemical deterioration. Results The laparotomy group included 82 patients and 68.2% of them had unnecessary laparotomies. The non-operative management group comprised 97 patients and 90.7% of them did not require subsequent laparotomy. Abdominal CT scan had a sensitivity of 88.9% and specificity of 100% in detection of intra-abdominal injuries. Follow-up CT scanning detected bowel injuries missed by initial CT scan in three patients. The non-operative management group had significantly lower post-operative complication rate than the laparotomy group (4.1% vs. 18.3%), with a significantly shorter length of stay. Conclusions Non-operative management is the optimal management strategy for stable patients with penetrating anterior abdominal stab to decrease unnecessary laparotomy rates, hospital stay and costs. Follow-up abdominal CT scanning facilitated the decision making for patients selected for non-operative management and is highly sensitive in the diagnosis of patients who require subsequent exploration.

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