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Sample records for radiation computed tomography

  1. Multi-detector computed tomography radiation doses in the follow ...

    African Journals Online (AJOL)

    2014-05-09

    detector computed tomography (MDCT) is the preferred modality for follow-up of paediatric neurosurgery patients. Serial imaging, however, has the disadvantage of an ionising radiation burden, which may be mitigated using the ...

  2. Multi-detector computed tomography radiation doses in the follow ...

    African Journals Online (AJOL)

    Background: Multi-detector computed tomography (MDCT) is the preferred modality for follow-up of paediatric neurosurgery patients. Serial imaging, however, has the disadvantage of an ionising radiation burden, which may be mitigated using the 'as low as reasonably achievable' (ALARA) principle. Objectives: The ...

  3. Strategies for Computed Tomography Radiation Dose Reduction in Pediatric Neuroimaging.

    Science.gov (United States)

    Albert, Gregory W; Glasier, Charles M

    2015-08-01

    Radiation exposure from diagnostic imaging is a significant concern, particularly in the care of pediatric patients. Computed tomography (CT) scanning is a significant source of radiation. To demonstrate that diagnostic quality CT images can be obtained while minimizing the effective radiation dose to the patient. In this retrospective cross-sectional study, noncontrast head CT scan data were reviewed, and indications for scans and estimated radiation dose delivered were recorded. The estimated effective radiation dose (EERD) for each CT protocol was reviewed. We identified 251 head CT scans in a single month. Of these, 96 scans were using a low-dose shunt protocol with a mean EERD of 0.82 mSv. The remaining 155 scans were performed using the standard protocol, and the mean EERD was 1.65 mSv. Overall, the EERD was minimized while maintaining diagnostic scan quality. Although replacing a CT with magnetic resonance imaging is ideal to completely avoid ionizing radiation, this is not always practical or preferred. Therefore, it is important to have CT protocols in place that minimize radiation dose without sacrificing diagnostic quality. The protocols in place at our institution could be replicated at other academic and community hospitals and imaging centers.

  4. Radiation Exposure of Abdominal Cone Beam Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sailer, Anna M., E-mail: anni.sailer@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands); Schurink, Geert Willem H., E-mail: gwh.schurink@mumc.nl [Maastricht University Medical Centre, Department of Surgery (Netherlands); Wildberger, Joachim E., E-mail: j.wildberger@mumc.nl; Graaf, Rick de, E-mail: r.de.graaf@mumc.nl; Zwam, Willem H. van, E-mail: w.van.zwam@mumc.nl; Haan, Michiel W. de, E-mail: m.de.haan@mumc.nl; Kemerink, Gerrit J., E-mail: gerrit.kemerink@mumc.nl; Jeukens, Cécile R. L. P. N., E-mail: cecile.jeukens@mumc.nl [Maastricht University Medical Centre (MUMC), Department of Radiology (Netherlands)

    2015-02-15

    PurposeTo evaluate patients radiation exposure of abdominal C-arm cone beam computed tomography (CBCT).MethodsThis prospective study was approved by the institutional review board; written, informed consent was waived. Radiation exposure of abdominal CBCT was evaluated in 40 patients who underwent CBCT during endovascular interventions. Dose area product (DAP) of CBCT was documented and effective dose (ED) was estimated based on organ doses using dedicated Monte Carlo simulation software with consideration of X-ray field location and patients’ individual body weight and height. Weight-dependent ED per DAP conversion factors were calculated. CBCT radiation dose was compared to radiation dose of procedural fluoroscopy. CBCT dose-related risk for cancer was assessed.ResultsMean ED of abdominal CBCT was 4.3 mSv (95 % confidence interval [CI] 3.9; 4.8 mSv, range 1.1–7.4 mSv). ED was significantly higher in the upper than in the lower abdomen (p = 0.003) and increased with patients’ weight (r = 0.55, slope = 0.045 mSv/kg, p < 0.001). Radiation exposure of CBCT corresponded to the radiation exposure of on average 7.2 fluoroscopy minutes (95 % CI 5.5; 8.8 min) in the same region of interest. Lifetime risk of exposure related cancer death was 0.033 % or less depending on age and weight.ConclusionsMean ED of abdominal CBCT was 4.3 mSv depending on X-ray field location and body weight.

  5. Trends in radiation protection of positron emission tomography/computed tomography imaging.

    Science.gov (United States)

    Alenezi, A; Soliman, K

    2015-06-01

    Over the past decade, the number of positron emission tomography/computed tomography (PET/CT) imaging procedures has increased substantially. This imaging technique provides accurate functional and anatomical information, particularly for oncological applications. Separately, both PET and CT are considered as high-dose imaging modalities. With the increased use of PET/CT, one could expect an increase in radiation doses to staff and patients. As such, major efforts have been made to reduce radiation dose in PET/CT facilities. Variations in working techniques have made it difficult to compare published results. This study aimed to review the literature on proposed methods to reduce patient and staff dose in clinical PET/CT imaging. A brief overview of some published information on staff and patient doses will be analysed and presented. Recent trends regarding radiation protection in PET/CT imaging will be discussed, and practical recommendations for reducing radiation doses to staff and patients will be discussed and summarised. Generally, the CT dose component is often higher in magnitude than the dose from PET alone; as such, focusing on CT dose reduction will decrease the overall patient dose in PET/CT imaging studies. The following factors should be considered in order to reduce the patient's dose from CT alone: proper justification for ordering contrast-enhanced CT; use of automatic exposure control features; use of adaptive statistical iterative reconstruction algorithms; and optimisation of scan parameters, especially scan length. The PET dose component can be reduced by administration of lower activity to the patient, optimisation of the workflow, and appropriate use of protective devices and engineered systems. At the international level, there is wide variation in work practices among institutions. The current observed trends are such that the annual dose limits for radiation workers in PET/CT imaging are unlikely to be exceeded. © Author(s) 2014.

  6. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  7. Use of Positron Emission Tomography/Computed Tomography in Radiation Treatment Planning for Lung Cancer

    Directory of Open Access Journals (Sweden)

    Kezban Berberoğlu

    2016-06-01

    Full Text Available Radiotherapy (RT plays an important role in the treatment of lung cancer. Accurate diagnosis and staging are crucial in the delivery of RT with curative intent. Target miss can be prevented by accurate determination of tumor contours during RT planning. Currently, tumor contours are determined manually by computed tomography (CT during RT planning. This method leads to differences in delineation of tumor volume between users. Given the change in RT tools and methods due to rapidly developing technology, it is now more significant to accurately delineate the tumor tissue. F18 fluorodeoxyglucose positron emission tomography/CT (F18 FDG PET/CT has been established as an accurate method in correctly staging and detecting tumor dissemination in lung cancer. Since it provides both anatomic and biologic information, F18 FDG PET decreases interuser variability in tumor delineation. For instance, tumor volumes may be decreased as atelectasis and malignant tissue can be more accurately differentiated, as well as better evaluation of benign and malignant lymph nodes given the difference in FDG uptake. Using F18 FDG PET/CT, the radiation dose can be escalated without serious adverse effects in lung cancer. In this study, we evaluated the contribution of F18 FDG PET/CT for RT planning in lung cancer.

  8. Lung cancer screening with low-radiation dose computed tomography after liver transplantation.

    Science.gov (United States)

    Herrero, Jose Ignacio; Bastarrika, Gorka; D'Avola, Delia; Montes, Usua; Pueyo, Jesus; Iñarrairaegui, Mercedes; Pardo, Fernando; Quiroga, Jorge; Zulueta, Javier

    2013-10-29

    Background The prognosis of non-cutaneous malignancies after liver transplantation is dismal, mainly because most cases are diagnosed at advanced stages. In the last decade, studies have shown the potential role of screening for lung cancer with low-radiation dose computed tomography. Material and Methods Fifty-nine liver transplant recipients with a cumulative dose of smoking greater than 10 pack-years were enrolled in a lung cancer screening program using yearly low-radiation dose computed tomography. Results Lung cancer was diagnosed in 7 patients (11.8%), 5 of which were in stage Ia at diagnosis. Patients with lung cancer were significantly older (median age 66 vs. 58 years), had a higher cumulative history of smoking, and had emphysema more frequently than patients without cancer. Conclusions Screening for lung cancer with low-radiation dose computed tomography in liver transplant recipients results in the diagnosis of lung cancer in early stages.

  9. Methods and compositions for protection of cells and tissues from computed tomography radiation

    Energy Technology Data Exchange (ETDEWEB)

    Grdina, David J.

    2018-01-30

    Described are methods for preventing or inhibiting genomic instability and in cells affected by diagnostic radiology procedures employing ionizing radiation. Embodiments include methods of preventing or inhibiting genomic instability and in cells affected by computed tomography (CT) radiation. Subjects receiving ionizing radiation may be those persons suspected of having cancer, or cancer patients having received or currently receiving cancer therapy, and or those patients having received previous ionizing radiation, including those who are approaching or have exceeded the recommended total radiation dose for a person.

  10. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the head uses special x-ray equipment to help assess head injuries, severe headaches, dizziness, and other symptoms of ... content. Related Articles and Media Radiation Dose in X-Ray and CT ... Perfusion of the Head CT Angiography (CTA) Stroke Brain Tumors Computer Tomography ( ...

  11. Quality assurance for computed-tomography simulators and the computed-tomography-simulation process: report of the AAPM Radiation Therapy Committee Task Group No. 66.

    Science.gov (United States)

    Mutic, Sasa; Palta, Jatinder R; Butker, Elizabeth K; Das, Indra J; Huq, M Saiful; Loo, Leh-Nien Dick; Salter, Bill J; McCollough, Cynthia H; Van Dyk, Jacob

    2003-10-01

    This document presents recommendations of the American Association of Physicists in Medicine (AAPM) for quality assurance of computed-tomography- (CT) simulators and CT-simulation process. This report was prepared by Task Group No. 66 of the AAPM Radiation Therapy Committee. It was approved by the Radiation Therapy Committee and by the AAPM Science Council.

  12. Computed Tomography Radiation Dose Reduction: Effect of Different Iterative Reconstruction Algorithms on Image Quality

    NARCIS (Netherlands)

    Willemink, M.J.; Takx, R.A.P.; Jong, P.A. de; Budde, R.P.; Bleys, R.L.; Das, M.; Wildberger, J.E.; Prokop, M.; Buls, N.; Mey, J. de; Leiner, T.; Schilham, A.M.

    2014-01-01

    We evaluated the effects of hybrid and model-based iterative reconstruction (IR) algorithms from different vendors at multiple radiation dose levels on image quality of chest phantom scans.A chest phantom was scanned on state-of-the-art computed tomography scanners from 4 vendors at 4 dose levels

  13. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... tissue, such as organs like the heart or liver, shows up in shades of gray, and air ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  14. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... tissue, such as organs like the heart or liver, shows up in shades of gray, and air ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others American Stroke Association National Stroke Association ... Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine ...

  16. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  17. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  18. The Impact of Iterative Reconstruction on Computed Tomography Radiation Dosimetry: Evaluation in a Routine Clinical Setting.

    Science.gov (United States)

    Moorin, Rachael E; Gibson, David A J; Forsyth, Rene K; Fox, Richard

    2015-01-01

    To evaluate the effect of introduction of iterative reconstruction as a mandated software upgrade on radiation dosimetry in routine clinical practice over a range of computed tomography examinations. Random samples of scanning data were extracted from a centralised Picture Archiving Communication System pertaining to 10 commonly performed computed tomography examination types undertaken at two hospitals in Western Australia, before and after the introduction of iterative reconstruction. Changes in the mean dose length product and effective dose were evaluated along with estimations of associated changes to annual cancer incidence. We observed statistically significant reductions in the effective radiation dose for head computed tomography (22-27%) consistent with those reported in the literature. In contrast the reductions observed for non-contrast chest (37-47%); chest pulmonary embolism study (28%), chest/abdominal/pelvic study (16%) and thoracic spine (39%) computed tomography. Statistically significant reductions in radiation dose were not identified in angiographic computed tomography. Dose reductions translated to substantial lowering of the lifetime attributable risk, especially for younger females, and estimated numbers of incident cancers. Reduction of CT dose is a priority Iterative reconstruction algorithms have the potential to significantly assist with dose reduction across a range of protocols. However, this reduction in dose is achieved via reductions in image noise. Fully realising the potential dose reduction of iterative reconstruction requires the adjustment of image factors and forgoing the noise reduction potential of the iterative algorithm. Our study has demonstrated a reduction in radiation dose for some scanning protocols, but not to the extent experimental studies had previously shown or in all protocols expected, raising questions about the extent to which iterative reconstruction achieves dose reduction in real world clinical practice.

  19. The Impact of Iterative Reconstruction on Computed Tomography Radiation Dosimetry: Evaluation in a Routine Clinical Setting.

    Directory of Open Access Journals (Sweden)

    Rachael E Moorin

    Full Text Available To evaluate the effect of introduction of iterative reconstruction as a mandated software upgrade on radiation dosimetry in routine clinical practice over a range of computed tomography examinations.Random samples of scanning data were extracted from a centralised Picture Archiving Communication System pertaining to 10 commonly performed computed tomography examination types undertaken at two hospitals in Western Australia, before and after the introduction of iterative reconstruction. Changes in the mean dose length product and effective dose were evaluated along with estimations of associated changes to annual cancer incidence.We observed statistically significant reductions in the effective radiation dose for head computed tomography (22-27% consistent with those reported in the literature. In contrast the reductions observed for non-contrast chest (37-47%; chest pulmonary embolism study (28%, chest/abdominal/pelvic study (16% and thoracic spine (39% computed tomography. Statistically significant reductions in radiation dose were not identified in angiographic computed tomography. Dose reductions translated to substantial lowering of the lifetime attributable risk, especially for younger females, and estimated numbers of incident cancers.Reduction of CT dose is a priority Iterative reconstruction algorithms have the potential to significantly assist with dose reduction across a range of protocols. However, this reduction in dose is achieved via reductions in image noise. Fully realising the potential dose reduction of iterative reconstruction requires the adjustment of image factors and forgoing the noise reduction potential of the iterative algorithm. Our study has demonstrated a reduction in radiation dose for some scanning protocols, but not to the extent experimental studies had previously shown or in all protocols expected, raising questions about the extent to which iterative reconstruction achieves dose reduction in real world clinical

  20. Radiation dose in paediatric computed tomography: risks and benefits

    African Journals Online (AJOL)

    The best available risk estimates suggest that paediatric CT will result in significantly increased lifetime radiation risk over adult CT. Studies have shown that lower milliampere-second (mAs) settings can be used for children without significant loss of information. Although the risk–benefit balance is still strongly tilted toward ...

  1. Readjustment of abdominal computed tomography protocols in a university hospital: impact on radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Romano, Ricardo Francisco Tavares; Salvadori, Priscila Silveira; Torres, Lucas Rios; Bretas, Elisa Almeida Sathler; Bekhor, Daniel; Medeiros, Regina Bitelli; D' Ippolito, Giuseppe, E-mail: ricardo.romano@unifesp.br [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina; Caldana, Rogerio Pedreschi [Fleury Medicina e Saude, Sao Paulo, SP (Brazil)

    2015-09-15

    Objective: To assess the reduction of estimated radiation dose in abdominal computed tomography following the implementation of new scan protocols on the basis of clinical suspicion and of adjusted images acquisition parameters. Materials and Methods: Retrospective and prospective review of reports on radiation dose from abdominal CT scans performed three months before (group A - 551 studies) and three months after (group B - 788 studies) implementation of new scan protocols proposed as a function of clinical indications. Also, the images acquisition parameters were adjusted to reduce the radiation dose at each scan phase. The groups were compared for mean number of acquisition phases, mean CTDI{sub vol} per phase, mean DLP per phase, and mean DLP per scan. Results: A significant reduction was observed for group B as regards all the analyzed aspects, as follows: 33.9%, 25.0%, 27.0% and 52.5%, respectively for number of acquisition phases, CTDI{sub vol} per phase, DLP per phase and DLP per scan (p < 0.001). Conclusion: The rational use of abdominal computed tomography scan phases based on the clinical suspicion in conjunction with the adjusted images acquisition parameters allows for a 50% reduction in the radiation dose from abdominal computed tomography scans. (author)

  2. Computed Tomography Angiography with a 192-slice Dual-source Computed Tomography System: Improvements in Image Quality and Radiation Dose

    Directory of Open Access Journals (Sweden)

    Philip V M Linsen

    2016-01-01

    Full Text Available Purpose: This study aims to compare image quality, radiation dose, and the influence of the heart rate on image quality of high-pitch spiral coronary computed tomography angiography (CCTA using 128-slice (second generation dual-source CT (DSCT and a 192-slice DSCT (third generation scanner. Materials and Methods: Two consecutive cohorts of fifty patients underwent CCTA by high-pitch spiral scan mode using 128 or 192-slice DSCT. The 192-slice DSCT system has a more powerful roentgen tube (2 × 120 kW that allows CCTA acquisition at lower tube voltages, wider longitudinal coverage for faster table speed (732 m/s, and the use of iterative reconstruction. Objective image quality was measured as the signal-to-noise ratio (SNR and contrast-to-noise ratio (CNR. Subjective image quality was evaluated using a Likert scale. Results: While the effective dose was lower with 192-slice DSCT (1.2 ± 0.5 vs. 0.6 ± 0.3 mSv; P < 0.001, the SNR (18.9 ± 4.3 vs. 11.0 ± 2.9; P < 0.001 and CNR (23.5 ± 4.8 vs. 14.3 ± 4.1; P < 0.001 were superior to 128-slice DSCT. Although patients scanned with 192-slice DSCT had a faster heart rate (59 ± 7 vs. 56 ± 6; P = 0.045, subjective image quality was scored higher (4.2 ± 0.8 vs. 3.0 ± 0.7; P < 0.001 compared to 128-slice DSCT. Conclusions: High-pitch spiral CCTA by 192-slice DSCT provides better image quality, despite a higher average heart rate, at lower radiation doses compared to 128-slice DSCT.

  3. Assessment of radiation exposure on a dual-source computed tomography-scanner performing coronary computed tomography-angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kirchhoff, S., E-mail: sonja.kirchhoff@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Herzog, P., E-mail: peter.herzog@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Johnson, T., E-mail: Thorsten.johnson@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Boehm, H., E-mail: holger.boehm@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Nikolaou, K., E-mail: konstantin.nikolaou@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Reiser, M.F., E-mail: maximilian.reiser@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany); Becker, C.H., E-mail: christoph.becker@med.uni-muenchen.d [Institute of Clinical Radiology, University Hospital Munich - Grosshadern, Ludwig Maximilians-Universitaet Muenchen, Klinikum Grosshadern, Marchioninistrasse 15, 81377 Munich (Germany)

    2010-06-15

    Objective: The radiation exposure of a dual-source-64-channel multi-detector-computed-tomography-scanner (Somatom-Defintion, Siemens, Germany) was assessed in a phantom-study performing coronary-CT-angiography (CTCA) in comparison to patients' data randomly selected from routine scanning. Methods: 240 CT-acquisitions of a computed tomography dose index (CTDI)-phantom (PTW, Freiburg, Germany) were performed using a synthetically generated Electrocardiography (ECG)-signal with variable heart rates (30-180 beats per minute (bpm)). 120 measurements were acquired using continuous tube-output; 120 measurements were performed using ECG-synchronized tube-modulation. The pulsing window was set at minimum duration at 65% of the cardiac cycle between 30 and 75 bpm. From 90-180 bpm the pulsing window was set at 30-70% of the cardiac cycle. Automated pitch adaptation was always used. A comparison between phantom CTDI and two patient groups' CTDI corresponding to the two pulsing groups was performed. Results: Without ECG-tube-modulation CDTI-values were affected by heart-rate-changes resulting in 85.7 mGray (mGy) at 30 and 45 bpm, 65.5 mGy/60 bpm, 54.7 mGy/75 bpm, 46.5 mGy/90 bpm, 34.2 mGy/120 bpm, 27.0 mGy/150 bpm and 22.1 mGy/180 bpm equal to effective doses between 14.5 mSievert (mSv) at 30/45 bpm and 3.6 mSv at 180 bpm. Using ECG-tube-modulation these CTDI-values resulted: 32.6 mGy/30 bpm, 36.6 mGy/45 bpm, 31.4 mGy/60 bpm, 26.8 mGy/75 bpm, 23.7 mGy/90 bpm, 19.4 mGy/120 bpm, 17.2 mGy/150 bpm and 15.6 mGy/180 bpm equal to effective doses between 5.5 mSv at 30 bpm and 2.6 mSv at 180 bpm. Significant CTDI-differences were found between patients with lower/moderate and higher heart rates in comparison to the phantom CTDI-results. Conclusions: Dual source CTCA is particularly dose efficient at high heart rates when automated pitch adaptation, especially in combination with ECG-based tube-modulation is used. However in clinical routine scanning for patients with higher

  4. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses ... of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

  5. Diagnostic accuracy of computed tomography using lower doses of radiation for patients with Crohn's disease.

    LENUS (Irish Health Repository)

    Craig, Orla

    2012-08-01

    Magnetic resonance and ultrasonography have increasing roles in the initial diagnosis of Crohn\\'s disease, but computed tomography (CT) with positive oral contrast agents is most frequently used to identify those with acute extramural complications. However, CT involves exposure of patients to radiation. We prospectively compared the diagnostic accuracy of low-dose CT (at a dose comparable to that used to obtain an abdominal radiograph) with conventional-dose CT in patients with active Crohn\\'s disease.

  6. Optimization of dose radiation and image quality on computed tomography of thorax in adult women

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Z, G. R.; Casian C, G. [Hospital Juarez de Mexico, Av. IPN No. 5160, 07760 Mexico D. F. (Mexico); Gaona, E.; Franco E, J. G.; Molina F, N., E-mail: gaen1310@correo.xoc.uam.mx [Universidad Autonoma Metropolitana, Unidad Xochimilco, Calz. del Hueso 1100, 04960 Mexico D. F. (Mexico)

    2015-10-15

    Full text: The objective of the study is the optimization of the dose (Dlp) and image quality in the exploration of adult women in studies of thorax with computed tomography (CT). The CT is a technique of exploration with high radiation doses to patients with an increase of the risk factors of developing cancer in the future, but X-rays are a very important medical diagnostic tool. We performed a retrospective survey of 50 female patients who had thorax tomography using the automatic protocol established by the manufacturer, a database of dose (Dlp), measures of patient A P and radiological parameters such as kV and m A was obtained. Subsequently, we carry out the prospective study with 30 patients with prescription of thorax tomography, scans were conducted with CT with reduced doses using manual techniques protocol of exploration while maintaining diagnostic image quality. The results show that the prospective study patients received doses lower than 30% on average. In general the dose patients were within the confidence interval of 95% of the levels of diagnostic reference (DRL) adopted by the European Community for CT and the most common value is 400 Dlp for thorax. Comparative image quality study was conducted using the protocol of the manufacturer and the manual protocol and image quality was diagnostic after dose reduction up to 30%. The reduction of radiation dose in female patients in studies of thorax CT helps to reduce risk factors of developing cancer later in life. A thorax tomography study includes the fibro-glandular tissue of the breast which is very sensitive to stochastic effects of radiation. (Author)

  7. Computed Tomography (CT) - Spine

    Science.gov (United States)

    ... Professions Site Index A-Z Computed Tomography (CT) - Spine Computed tomography (CT) of the spine is a ... the Spine? What is CT Scanning of the Spine? Computed tomography, more commonly known as a CT ...

  8. Radiation Dose Reduction in Computed Tomography-Guided Lung Interventions using an Iterative Reconstruction Technique.

    Science.gov (United States)

    Chang, D H; Hiss, S; Mueller, D; Hellmich, M; Borggrefe, J; Bunck, A C; Maintz, D; Hackenbroch, M

    2015-10-01

    To compare the radiation doses and image qualities of computed tomography (CT)-guided interventions using a standard-dose CT (SDCT) protocol with filtered back projection and a low-dose CT (LDCT) protocol with both filtered back projection and iterative reconstruction. Image quality and radiation doses (dose-length product and CT dose index) were retrospectively reviewed for 130 patients who underwent CT-guided lung interventions. SDCT at 120 kVp and automatic mA modulation and LDCT at 100 kVp and a fixed exposure were each performed for 65 patients. Image quality was objectively evaluated as the contrast-to-noise ratio and subjectively by two radiologists for noise impression, sharpness, artifacts and diagnostic acceptability on a four-point scale. The groups did not significantly differ in terms of diagnostic acceptability and complication rate. LDCT yielded a median 68.6% reduction in the radiation dose relative to SDCT. In the LDCT group, iterative reconstruction was superior to filtered back projection in terms of noise reduction and subjective image quality. The groups did not differ in terms of beam hardening artifacts. LDCT was feasible for all procedures and yielded a more than two-thirds reduction in radiation exposure while maintaining overall diagnostic acceptability, safety and precision. The iterative reconstruction algorithm is preferable according to the objective and subjective image quality analyses. Implementation of a low-dose computed tomography (LDCT) protocol for lung interventions is feasible and safe. LDCT protocols yield a significant reduction (more than 2/3) in radiation exposure. Iterative reconstruction algorithms considerably improve the image quality in LDCT protocols. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Computed Tomography Density Change in the Thyroid Gland Before and After Radiation Therapy.

    Science.gov (United States)

    Ishibashi, Naoya; Maebayashi, Toshiya; Aizawa, Takuya; Sakaguchi, Masakuni; Okada, Masahiro; Matsushita, Junichi

    2018-01-01

    Hypothyroidism is an established adverse effect of radiation therapy for head and neck cancer, and computed tomography (CT) density of the thyroid gland is lower in hypothyroid than euthyroid individuals. No previous studies have evaluated changes in CT densities of the thyroid gland caused by radiation therapy. The aim was to investigate the relationship between the change in CT density of the thyroid gland before and after radiation therapy for head and neck cancer and hypothyroidism. This retrospective study analyzed data of 24 patients treated by radiation therapy for head and neck cancers. After dosimetric analysis of received radiation therapy, a Picture Archiving and Communication System was used to manually contour the thyroid on pre-treatment CT images to enable determination of mean thyroid gland CT densities and received radiation doses. Pre- and post-treatment thyroid function was assessed on the basis of serum TSH concentrations. Multivariate and univariate analyses were used to determine what clinical factors are associated with post-radiation therapy decrease in CT density of the thyroid and Pearson's χ 2 test was used to assess correlations between these densities and TSH concentrations. Mean CT densities of the thyroid gland decreased from before to after radiation therapy in 73.9% of our patients (median decrease 16.8 HU). Serum TSH concentrations were significantly higher in patients with greater then median decreases in CT density than in those with lesser or no decreases. Post-radiation therapy hypothyroidism may be predicted by significant decreases in CT density of the thyroid gland. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  10. The use of mobile computed tomography in intensive care: regulatory compliance and radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, G C; Rowles, N P; Loader, R [Healthcare Science and Technology Directorate, Plymouth Hospitals NHS Trust (United Kingdom); Foy, R T [Department of Medical Physics, Royal Cornwall NHS Trust (United Kingdom); Barua, N; Williams, A; Palmer, J D [South West Neurosurgery Centre, Plymouth Hospitals NHS Trust (United Kingdom)], E-mail: Gregory.Stevens@phnt.swest.nhs.uk

    2009-12-01

    The use of mobile head computed tomography (CT) equipment in intensive care is of benefit to unstable patients with brain injury. However, ionising radiation in a ward environment presents difficulties due to the necessity to restrict the exposure to staff and members of the public according to regulation 8(1-2) of the Ionising Radiation Regulations 1999. The methodology for enabling the use of a mobile head CT unit in an open ward area is discussed and a practical solution given. This required the reduction in scatter doses through the installation of extra internal and external shielding, and a further reduction in annual scatter dose by restricting the use of the equipment based on a simulation of the annual ward workload.

  11. Childhood exposure to ionizing radiation from computed tomography imaging in Nova Scotia.

    Science.gov (United States)

    Inman, Mark; Otley, Anthony; Dummer, Trevor; Cui, Yunsong; Schmidt, Matthias H; Parker, Louise

    2015-10-01

    Examining radiation dose in the paediatric population is particularly important due to the vulnerability of paediatric patients (increased radiosensitive tissues and postexposure life-years) and risk for future radiogenic malignancy. To evaluate trends in paediatric computed tomography (CT) use and ionizing radiation exposure using population-based data from Nova Scotia. A retrospective, population-based cohort study of CT use in patients Nova Scotia. CT examination data were retrieved from a provincial imaging repository. Trends in CT use were described, and both annual and cumulative effective dose exposures were calculated. In total, 29,452 CT events, involving up to 22,867 individuals were retrieved. Overall annual paediatric CT examination rates remained static (range 17.4 to 18.8 per 1000 per year). However, use in children 50% (P50 mSv), and rates in individuals >15 years of age steadily increased, suggesting further exposure reduction efforts are necessary.

  12. Ambient radiation levels in positron emission tomography/computed tomography (PET/CT) imaging center

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Priscila do Carmo; Oliveira, Paulo Marcio Campos de; Mamede, Marcelo; Silveira, Mariana de Castro; Aguiar, Polyanna; Real, Raphaela Vila, E-mail: pridili@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Silva, Teogenes Augusto da [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-01-15

    Objective: to evaluate the level of ambient radiation in a PET/CT center. Materials and methods: previously selected and calibrated TLD-100H thermoluminescent dosimeters were utilized to measure room radiation levels. During 32 days, the detectors were placed in several strategically selected points inside the PET/CT center and in adjacent buildings. After the exposure period the dosimeters were collected and processed to determine the radiation level. Results: in none of the points selected for measurements the values exceeded the radiation dose threshold for controlled area (5 mSv/ year) or free area (0.5 mSv/year) as recommended by the Brazilian regulations. Conclusion: in the present study the authors demonstrated that the whole shielding system is appropriate and, consequently, the workers are exposed to doses below the threshold established by Brazilian standards, provided the radiation protection standards are followed. (author)

  13. Ambient radiation levels in positron emission tomography/computed tomography (PET/CT) imaging center

    Science.gov (United States)

    Santana, Priscila do Carmo; de Oliveira, Paulo Marcio Campos; Mamede, Marcelo; Silveira, Mariana de Castro; Aguiar, Polyanna; Real, Raphaela Vila; da Silva, Teógenes Augusto

    2015-01-01

    Objective To evaluate the level of ambient radiation in a PET/CT center. Materials and Methods Previously selected and calibrated TLD-100H thermoluminescent dosimeters were utilized to measure room radiation levels. During 32 days, the detectors were placed in several strategically selected points inside the PET/CT center and in adjacent buildings. After the exposure period the dosimeters were collected and processed to determine the radiation level. Results In none of the points selected for measurements the values exceeded the radiation dose threshold for controlled area (5 mSv/year) or free area (0.5 mSv/year) as recommended by the Brazilian regulations. Conclusion In the present study the authors demonstrated that the whole shielding system is appropriate and, consequently, the workers are exposed to doses below the threshold established by Brazilian standards, provided the radiation protection standards are followed. PMID:25798004

  14. Radiation dose of cone-beam computed tomography compared to conventional radiographs in orthodontics.

    Science.gov (United States)

    Signorelli, Luca; Patcas, Raphael; Peltomäki, Timo; Schätzle, Marc

    2016-01-01

    The aim of this study was to determine radiation doses of different cone-beam computed tomography (CBCT) scan modes in comparison to a conventional set of orthodontic radiographs (COR) by means of phantom dosimetry. Thermoluminescent dosimeter (TLD) chips (3 × 1 × 1 mm) were used on an adult male tissue-equivalent phantom to record the distribution of the absorbed radiation dose. Three different scanning modes (i.e., portrait, normal landscape, and fast scan landscape) were compared to CORs [i.e., conventional lateral (LC) and posteroanterior (PA) cephalograms and digital panoramic radiograph (OPG)]. The following radiation levels were measured: 131.7, 91, and 77 μSv in the portrait, normal landscape, and fast landscape modes, respectively. The overall effective dose for a COR was 35.81 μSv (PA: 8.90 μSv; OPG: 21.87 μSv; LC: 5.03 μSv). Although one CBCT scan may replace all CORs, one set of CORs still entails 2-4 times less radiation than one CBCT. Depending on the scan mode, the radiation dose of a CBCT is about 3-6 times an OPG, 8-14 times a PA, and 15-26 times a lateral LC. Finally, in order to fully reconstruct cephalograms including the cranial base and other important structures, the CBCT portrait mode must be chosen, rendering the difference in radiation exposure even clearer (131.7 vs. 35.81 μSv). Shielding radiation-sensitive organs can reduce the effective dose considerably. CBCT should not be recommended for use in all orthodontic patients as a substitute for a conventional set of radiographs. In CBCT, reducing the height of the field of view and shielding the thyroid are advisable methods and must be implemented to lower the exposure dose.

  15. Comparison of Diagnostic Accuracy of Radiation Dose-Equivalent Radiography, Multidetector Computed Tomography and Cone Beam Computed Tomography for Fractures of Adult Cadaveric Wrists.

    Science.gov (United States)

    Neubauer, Jakob; Benndorf, Matthias; Reidelbach, Carolin; Krauß, Tobias; Lampert, Florian; Zajonc, Horst; Kotter, Elmar; Langer, Mathias; Fiebich, Martin; Goerke, Sebastian M

    2016-01-01

    To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT) and to radiography equivalent dose cone beam computed tomography (RED-CBCT) for wrist fractures. As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100) were artificially fractured in random order in a controlled experimental setting. We performed radiation dose equivalent radiography (settings as in standard clinical care), RED-MDCT in a 320 row MDCT with single shot mode and RED-CBCT in a device dedicated to musculoskeletal imaging. Three raters independently evaluated the resulting images for fractures and the level of confidence for each finding. Gold standard was evaluated by consensus reading of a high-dose MDCT. Pooled sensitivity was higher in RED-MDCT with 0.89 and RED-MDCT with 0.81 compared to radiography with 0.54 (P = radiography (P radiography. Readers are more confident in their reporting with the cross sectional modalities. Dose equivalent cross sectional computed tomography of the wrist could replace plain radiography for fracture diagnosis in the long run.

  16. Comparison of Diagnostic Accuracy of Radiation Dose-Equivalent Radiography, Multidetector Computed Tomography and Cone Beam Computed Tomography for Fractures of Adult Cadaveric Wrists.

    Directory of Open Access Journals (Sweden)

    Jakob Neubauer

    Full Text Available To compare the diagnostic accuracy of radiography, to radiography equivalent dose multidetector computed tomography (RED-MDCT and to radiography equivalent dose cone beam computed tomography (RED-CBCT for wrist fractures.As study subjects we obtained 10 cadaveric human hands from body donors. Distal radius, distal ulna and carpal bones (n = 100 were artificially fractured in random order in a controlled experimental setting. We performed radiation dose equivalent radiography (settings as in standard clinical care, RED-MDCT in a 320 row MDCT with single shot mode and RED-CBCT in a device dedicated to musculoskeletal imaging. Three raters independently evaluated the resulting images for fractures and the level of confidence for each finding. Gold standard was evaluated by consensus reading of a high-dose MDCT.Pooled sensitivity was higher in RED-MDCT with 0.89 and RED-MDCT with 0.81 compared to radiography with 0.54 (P = < .004. No significant differences were detected concerning the modalities' specificities (with values between P = .98. Raters' confidence was higher in RED-MDCT and RED-CBCT compared to radiography (P < .001.The diagnostic accuracy of RED-MDCT and RED-CBCT for wrist fractures proved to be similar and in some parts even higher compared to radiography. Readers are more confident in their reporting with the cross sectional modalities. Dose equivalent cross sectional computed tomography of the wrist could replace plain radiography for fracture diagnosis in the long run.

  17. Nationwide radiation dose survey of computed tomography for fetal skeletal dysplasias

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Osamu [National Center for Child Health and Development, Department of Radiology, Setagaya-ku, Tokyo (Japan); Sawai, Hideaki [Hyogo College of Medicine, Department of Obstetrics and Gynecology, Nishinomiya-shi, Hyogo (Japan); Murotsuki, Jun [Miyagi Children' s Hospital, Department of Maternal and Fetal Medicine, Sendai-shi, Miyagi (Japan); Tohoku University Graduate School of Medicine, Department of Advanced Fetal and Developmental Medicine, Sendai-shi, Miyagi (Japan); Nishimura, Gen [Tokyo Metropolitan Children' s Medical Center, Department of Pediatric Imaging, Fuchu-shi, Tokyo (Japan); Horiuchi, Tetsuya [National Center for Child Health and Development, Department of Radiology, Setagaya-ku, Tokyo (Japan); Osaka University, Department of Medical Physics and Engineering, Division of Medical Technology and Science, Course of Health Science, Graduate School of Medicine, Suita, Osaka (Japan)

    2014-08-15

    Recently, computed tomography (CT) has been used to diagnose fetal skeletal dysplasia. However, no surveys have been conducted to determine the radiation exposure dose and the diagnostic reference level (DRL). To collect CT dose index volume (CTDIvol) and dose length product (DLP) data from domestic hospitals implementing fetal skeletal 3-D CT and to establish DRLs for Japan. Scan data of 125 cases of 20 protocols from 16 hospitals were analyzed. The minimum, first-quartile, median, third-quartile and maximum values of CTDIvol and DLP were determined. The time-dependent change in radiation dose setting in hospitals with three or more cases with scans was also examined. The minimum, first-quartile, median, third-quartile and maximum CTDIvol values were 2.1, 3.7, 7.7, 11.3 and 23.1 mGy, respectively, and these values for DLP were 69.0, 122.3, 276.8, 382.6 and 1025.6 mGy.cm, respectively. Six of the 12 institutions reduced the dose setting during the implementation period. The DRLs of CTDIvol and DLP for fetal CT were 11.3 mGy and 382.6 mGy.cm, respectively. Institutions implementing fetal CT should use these established DRLs as the standard and make an effort to reduce radiation exposure by voluntarily decreasing the dose. (orig.)

  18. Estimation of radiation exposure from lung cancer screening program with low-dose computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Su Yeon; Jun, Jae Kwan [Graduate School of Cancer Science and Policy, National Cancer Center, Seoul (Korea, Republic of)

    2016-12-15

    The National Lung Screening Trial (NLST) demonstrated that screening with Low-dose Computed Tomography (LDCT) screening reduced lung cancer mortality in a high-risk population. Recently, the United States Preventive Services Task Force (USPSTF) gave a B recommendation for annual LDCT screening for individuals at high-risk. With the promising results, Korea developed lung cancer screening guideline and is planning a pilot study for implementation of national lung cancer screening. With widespread adoption of lung cancer screening with LDCT, there are concerns about harms of screening, including high false-positive rates and radiation exposure. Over the 3 rounds of screening in the NLST, 96.4% of positive results were false-positives. Although the initial screening is performed at low dose, subsequent diagnostic examinations following positive results additively contribute to patient's lifetime exposure. As with implementing a large-scale screening program, there is a lack of established risk assessment about the effect of radiation exposure from long-term screening program. Thus, the purpose of this study was to estimate cumulative radiation exposure of annual LDCT lung cancer screening program over 20-year period.

  19. Optimizing Cone Beam Computed Tomography (CBCT) System for Image Guided Radiation Therapy

    Science.gov (United States)

    Park, Chun Joo

    Cone Beam Computed Tomography (CBCT) system is the most widely used imaging device in image guided radiation therapy (IGRT), where set of 3D volumetric image of patient can be reconstructed to identify and correct position setup errors prior to the radiation treatment. This CBCT system can significantly improve precision of on-line setup errors of patient position and tumor target localization prior to the treatment. However, there are still a number of issues that needs to be investigated with CBCT system such as 1) progressively increasing defective pixels in imaging detectors by its frequent usage, 2) hazardous radiation exposure to patients during the CBCT imaging, 3) degradation of image quality due to patients' respiratory motion when CBCT is acquired and 4) unknown knowledge of certain anatomical features such as liver, due to lack of soft-tissue contrast which makes tumor motion verification challenging. In this dissertation, we explore on optimizing the use of cone beam computed tomography (CBCT) system under such circumstances. We begin by introducing general concept of IGRT. We then present the development of automated defective pixel detection algorithm for X-ray imagers that is used for CBCT imaging using wavelet analysis. We next investigate on developing fast and efficient low-dose volumetric reconstruction techniques which includes 1) fast digital tomosynthesis reconstruction using general-purpose graphics processing unit (GPGPU) programming and 2) fast low-dose CBCT image reconstruction based on the Gradient-Projection-Barzilai-Borwein formulation (GP-BB). We further developed two efficient approaches that could reduce the degradation of CBCT images from respiratory motion. First, we propose reconstructing four dimensional (4D) CBCT and DTS using respiratory signal extracted from fiducial markers implanted in liver. Second, novel motion-map constrained image reconstruction (MCIR) is proposed that allows reconstruction of high quality and high phase

  20. A comparative study for image quality and radiation dose of a cone beam computed tomography scanner and a multislice computed tomography scanner for paranasal sinus imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cock, Jens de; Canning, John [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Zanca, Federica; Hermans, Robert [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); KU Leuven, Imaging and Pathology Department, Leuven (Belgium); Pauwels, Ruben [KU Leuven, Imaging and Pathology Department, Leuven (Belgium)

    2015-07-15

    To evaluate image quality and radiation dose of a state of the art cone beam computed tomography (CBCT) system and a multislice computed tomography (MSCT) system in patients with sinonasal poliposis. In this retrospective study two radiologists evaluated 57 patients with sinonasal poliposis who underwent a CBCT or MSCT sinus examination, along with a control group of 90 patients with normal radiological findings. Tissue doses were measured using a phantom model with thermoluminescent dosimeters (TLD). Overall image quality in CBCT was scored significantly higher than in MSCT in patients with normal radiologic findings (p-value: 0.00001). In patients with sinonasal poliposis, MSCT scored significantly higher than CBCT (p-value: 0.00001). The average effective dose for MSCT was 42 % higher compared to CBCT (108 μSv vs 63 μSv). CBCT and MSCT are both suited for the evaluation of sinonasal poliposis. In patients with sinonasal poliposis, clinically important structures of the paranasal sinuses can be better delineated with MSCT, whereas in patients without sinonasal poliposis, CBCT turns out to define the important structures of the sinonasal region better. However, given the lower radiation dose, CBCT can be considered for the evaluation of the sinonasal structures in patients with sinonasal poliposis. (orig.)

  1. Radiation exposure for coronary artery calcium score at prospective 320 row multi-detector computed tomography

    Directory of Open Access Journals (Sweden)

    Faisal Khosa

    2013-12-01

    calcium score at prospective 320 row multi-detector computed tomography. Int J Cancer Ther Oncol 2013; 1(2:01023.DOI: http://dx.doi.org/10.14319/ijcto.0102.3

  2. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT of the sinuses is primarily used ...

  3. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray ... Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

  4. Optimizing Radiation Doses for Computed Tomography Across Institutions: Dose Auditing and Best Practices.

    Science.gov (United States)

    Demb, Joshua; Chu, Philip; Nelson, Thomas; Hall, David; Seibert, Anthony; Lamba, Ramit; Boone, John; Krishnam, Mayil; Cagnon, Christopher; Bostani, Maryam; Gould, Robert; Miglioretti, Diana; Smith-Bindman, Rebecca

    2017-06-01

    Radiation doses for computed tomography (CT) vary substantially across institutions. To assess the impact of institutional-level audit and collaborative efforts to share best practices on CT radiation doses across 5 University of California (UC) medical centers. In this before/after interventional study, we prospectively collected radiation dose metrics on all diagnostic CT examinations performed between October 1, 2013, and December 31, 2014, at 5 medical centers. Using data from January to March (baseline), we created audit reports detailing the distribution of radiation dose metrics for chest, abdomen, and head CT scans. In April, we shared reports with the medical centers and invited radiology professionals from the centers to a 1.5-day in-person meeting to review reports and share best practices. We calculated changes in mean effective dose 12 weeks before and after the audits and meeting, excluding a 12-week implementation period when medical centers could make changes. We compared proportions of examinations exceeding previously published benchmarks at baseline and following the audit and meeting, and calculated changes in proportion of examinations exceeding benchmarks. Of 158 274 diagnostic CT scans performed in the study period, 29 594 CT scans were performed in the 3 months before and 32 839 CT scans were performed 12 to 24 weeks after the audit and meeting. Reductions in mean effective dose were considerable for chest and abdomen. Mean effective dose for chest CT decreased from 13.2 to 10.7 mSv (18.9% reduction; 95% CI, 18.0%-19.8%). Reductions at individual medical centers ranged from 3.8% to 23.5%. The mean effective dose for abdominal CT decreased from 20.0 to 15.0 mSv (25.0% reduction; 95% CI, 24.3%-25.8%). Reductions at individual medical centers ranged from 10.8% to 34.7%. The number of CT scans that had an effective dose measurement that exceeded benchmarks was reduced considerably by 48% and 54% for chest and abdomen, respectively. After

  5. Quantitative measurement of regional lung gas volume by synchrotron radiation computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Monfraix, Sylvie [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Bayat, Sam [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Porra, Liisa [Department of Physical Sciences, University of Helsinki, POB 64, FIN-00014 Helsinki (Finland); Berruyer, Gilles [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Nemoz, Christian [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Thomlinson, William [Canadian Light Source, 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada); Suortti, Pekka [Department of Physical Sciences, University of Helsinki, POB 64, FIN-00014 Helsinki (Finland); Sovijaervi, Anssi R A [Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, POB 340, FIN-00029 HUS, Helsinki (Finland)

    2005-01-07

    The aim of this study was to assess the feasibility of a novel respiration-gated spiral synchrotron radiation computed tomography (SRCT) technique for direct quantification of absolute regional lung volumes, using stable xenon (Xe) gas as an inhaled indicator. Spiral SRCT with K-edge subtraction using two monochromatic x-ray beams was used to visualize and directly quantify inhaled Xe concentrations and airspace volumes in three-dimensional (3D) reconstructed lung images. Volume measurements were validated using a hollow Xe-filled phantom. Spiral images spanning 49 mm in lung height were acquired following 60 breaths of an 80% Xe-20% O{sub 2} gas mixture, in two anaesthetized and mechanically ventilated rabbits at baseline and after histamine aerosol inhalation. Volumetric images of 20 mm lung sections were obtained at functional residual capacity (FRC) and at end-inspiration. 3D images showed large patchy filling defects in peripheral airways and alveoli following histamine provocation. Local specific lung compliance was calculated based on FRC/end-inspiration images in normal lung. This study demonstrates spiral SRCT as a new technique for direct determination of regional lung volume, offering possibilities for non-invasive investigation of regional lung function and mechanics, with a uniquely high spatial resolution. An example of non-uniform volume distribution in rabbit lung following histamine inhalation is presented.

  6. Measurement of the linear attenuation coefficients of breast tissues by synchrotron radiation computed tomography

    Science.gov (United States)

    Chen, R. C.; Longo, R.; Rigon, L.; Zanconati, F.; De Pellegrin, A.; Arfelli, F.; Dreossi, D.; Menk, R.-H.; Vallazza, E.; Xiao, T. Q.; Castelli, E.

    2010-09-01

    The measurement of the linear attenuation coefficients of breast tissues is of fundamental importance in the field of breast x-ray diagnostic imaging. Different groups have evaluated the linear attenuation coefficients of breast tissues by carrying out direct attenuation measurements in which the specimens were thin and selected as homogeneous as possible. Here, we use monochromatic and high-intensity synchrotron radiation computed tomography (SR CT) to evaluate the linear attenuation coefficients of surgical breast tissues in the energy range from 15 to 26.5 keV. X-ray detection is performed by a custom digital silicon micro-strip device, developed in the framework of the PICASSO INFN experiment. Twenty-three human surgical breast samples were selected for SR CT and histological study. Six of them underwent CT, both as fresh tissue and after formalin fixation, while the remaining 17 were imaged only as formalin-fixed tissues. Our results for fat and fibrous tissues are in good agreement with the published values. However, in contrast to the published data, our measurements show no significant differences between fibrous and tumor tissues. Moreover, our results for fresh and formalin-fixed tissues demonstrate a reduction of the linear attenuation coefficient for fibrous and tumor tissues after fixation.

  7. Pilot study for the establishment of biomarkers for radiation damage after computed tomography in children.

    Science.gov (United States)

    Halm, Brunhild M; Franke, Adrian A; Lai, Jennifer F; Li, Xingnan; Custer, Laurie J; Pagano, Ian; Cooney, Robert V; Turner, Helen C; Brenner, David J

    2015-03-01

    Computed tomography (CT) is an imaging modality that exposes patients to ionizing radiation (IR). We review and report findings from our pilot study evaluating whether blood markers are altered in 17 children undergoing medically indicated CT scans. Blood was drawn before ('pre-CT') and 1 hour after ('post-CT' CT scans. Plasma carotenoids, tocopherols, Q10, ascorbic acid (AA) and uric acid (UA) were analyzed by RP-HPLC with diode-array and electrochemical detection. Dehydroascorbic acid (DHAA) was calculated by subtraction from total AA. Total antioxidant capacity (TAC) was measured using the ORAC assay. Cytokines were quantified using a multiplex immunoassay. γ-H2AX foci were visualized using immunofluorescence. Mean pre- and post-CT changes were compared using t-tests; P-levels children). Our results suggest that CT-derived IR can influence the antioxidant system and may elicit detrimental responses on the cellular level of young children. When possible and if appropriate non-IR based techniques such as ultrasound or magnetic resonance imaging should be used.

  8. Imaging of lung function using synchrotron radiation computed tomography: What's new?

    Energy Technology Data Exchange (ETDEWEB)

    Bayat, Sam [Universite de Picardie Jules Verne, Departement de Physiologie, DMAG EA 3901, 3 Rue des Louvels, 80036 Amiens Cedex 1 (France)], E-mail: Bayat.Sam@chu-amiens.fr; Porra, Liisa [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble (France); Department of Physics, POB 64, FIN-00014 University of Helsinki, Helsinki (Finland)], E-mail: porra@esrf.fr; Suhonen, Heikki [Department of Physics, POB 64, FIN-00014 University of Helsinki, Helsinki (Finland)], E-mail: heikki.suhonen@helsinki.fi; Janosi, Tibor [Geneva Children' s Hospital, University Hospitals of Geneva and University of Geneva, Geneva (Switzerland)], E-mail: janosit@dmi.u-szeged.hu; Strengell, Satu [Department of Physics, POB 64, FIN-00014 University of Helsinki, Helsinki (Finland)], E-mail: skstreng@mappi.helsinki.fi; Habre, Walid [Geneva Children' s Hospital, University Hospitals of Geneva and University of Geneva, Geneva (Switzerland)], E-mail: Walid.Habre@hcuge.ch; Petak, Ferenc [Department of Department of Medical Informatics and Engineering, University of Szeged, 6720 Szeged, Koranyi fasor 9 (Hungary)], E-mail: petak@dmi.szote.u-szeged.hu; Hantos, Zoltan [Department of Department of Medical Informatics and Engineering, University of Szeged, 6720 Szeged, Koranyi fasor 9 (Hungary)], E-mail: hantos@dmi.u-szeged.hu; Suortti, Pekka [Department of Physics, POB 64, FIN-00014 University of Helsinki, Helsinki (Finland)], E-mail: Pekka.Suortti@helsinki.fi; Sovijaervi, Anssi [Departments of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, POB 340, FIN-00029 HUS, Helsinki (Finland)], E-mail: anssi.sovijarvi@hus.fi

    2008-12-15

    There is a growing interest in imaging techniques as non-invasive means of quantitatively measuring regional lung structure and function. Abnormalities in lung ventilation due to alterations in airway function such as those observed in asthma and COPD are highly heterogeneous, and experimental methods to study this heterogeneity are crucial for better understanding of disease mechanisms and drug targeting strategies. In severe obstructive diseases requiring mechanical ventilation, the optimal ventilatory strategy to achieve recruitment of poorly ventilated lung zones remains a matter of considerable debate. We have used synchrotron radiation computed tomography (SRCT) for the in vivo study of regional lung ventilation and airway function. This imaging technique allows direct quantification of stable Xenon (Xe) gas used as an inhaled contrast agent using K-edge subtraction imaging. Dynamics of Xe wash-in can be used to calculate quantitative maps of regional specific lung ventilation. More recently, the development of Spiral-CT has allowed the acquisition of 3D images of the pulmonary bronchial tree and airspaces. This technique gives access to quantitative measurements of regional lung volume, ventilation, and mechanical properties. Examples of application in an experimental model of allergic asthma and in imaging lung recruitment as a function of mechanical ventilation parameters will be presented. The future orientations of this tecnique will be discussed.

  9. Measurement of the linear attenuation coefficients of breast tissues by synchrotron radiation computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, R C; Xiao, T Q [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai (China); Longo, R; Arfelli, F; Castelli, E [Department of Physics, University of Trieste, Trieste (Italy); Rigon, L; Dreossi, D; Menk, R-H; Vallazza, E [INFN, Sezione di Trieste, Trieste (Italy); Zanconati, F; De Pellegrin, A, E-mail: rongchang.chen@gmail.co [Department of Pathologic Anatomy, University of Trieste, Trieste (Italy)

    2010-09-07

    The measurement of the linear attenuation coefficients of breast tissues is of fundamental importance in the field of breast x-ray diagnostic imaging. Different groups have evaluated the linear attenuation coefficients of breast tissues by carrying out direct attenuation measurements in which the specimens were thin and selected as homogeneous as possible. Here, we use monochromatic and high-intensity synchrotron radiation computed tomography (SR CT) to evaluate the linear attenuation coefficients of surgical breast tissues in the energy range from 15 to 26.5 keV. X-ray detection is performed by a custom digital silicon micro-strip device, developed in the framework of the PICASSO INFN experiment. Twenty-three human surgical breast samples were selected for SR CT and histological study. Six of them underwent CT, both as fresh tissue and after formalin fixation, while the remaining 17 were imaged only as formalin-fixed tissues. Our results for fat and fibrous tissues are in good agreement with the published values. However, in contrast to the published data, our measurements show no significant differences between fibrous and tumor tissues. Moreover, our results for fresh and formalin-fixed tissues demonstrate a reduction of the linear attenuation coefficient for fibrous and tumor tissues after fixation.

  10. Quantitative measurement of regional lung gas volume by synchrotron radiation computed tomography

    Science.gov (United States)

    Monfraix, Sylvie; Bayat, Sam; Porra, Liisa; Berruyer, Gilles; Nemoz, Christian; Thomlinson, William; Suortti, Pekka; Sovijärvi, Anssi R. A.

    2005-01-01

    The aim of this study was to assess the feasibility of a novel respiration-gated spiral synchrotron radiation computed tomography (SRCT) technique for direct quantification of absolute regional lung volumes, using stable xenon (Xe) gas as an inhaled indicator. Spiral SRCT with K-edge subtraction using two monochromatic x-ray beams was used to visualize and directly quantify inhaled Xe concentrations and airspace volumes in three-dimensional (3D) reconstructed lung images. Volume measurements were validated using a hollow Xe-filled phantom. Spiral images spanning 49 mm in lung height were acquired following 60 breaths of an 80% Xe-20% O2 gas mixture, in two anaesthetized and mechanically ventilated rabbits at baseline and after histamine aerosol inhalation. Volumetric images of 20 mm lung sections were obtained at functional residual capacity (FRC) and at end-inspiration. 3D images showed large patchy filling defects in peripheral airways and alveoli following histamine provocation. Local specific lung compliance was calculated based on FRC/end-inspiration images in normal lung. This study demonstrates spiral SRCT as a new technique for direct determination of regional lung volume, offering possibilities for non-invasive investigation of regional lung function and mechanics, with a uniquely high spatial resolution. An example of non-uniform volume distribution in rabbit lung following histamine inhalation is presented.

  11. Computed tomography imaging parameters for inhomogeneity correction in radiation treatment planning

    Directory of Open Access Journals (Sweden)

    Indra J Das

    2016-01-01

    Full Text Available Modern treatment planning systems provide accurate dosimetry in heterogeneous media (such as a patient' body with the help of tissue characterization based on computed tomography (CT number. However, CT number depends on the type of scanner, tube voltage, field of view (FOV, reconstruction algorithm including artifact reduction and processing filters. The impact of these parameters on CT to electron density (ED conversion had been subject of investigation for treatment planning in various clinical situations. This is usually performed with a tissue characterization phantom with various density plugs acquired with different tube voltages (kilovoltage peak, FOV reconstruction and different scanners to generate CT number to ED tables. This article provides an overview of inhomogeneity correction in the context of CT scanning and a new evaluation tool, difference volume dose-volume histogram (DVH, dV-DVH. It has been concluded that scanner and CT parameters are important for tissue characterizations, but changes in ED are minimal and only pronounced for higher density materials. For lungs, changes in CT number are minimal among scanners and CT parameters. Dosimetric differences for lung and prostate cases are usually insignificant (<2% in three-dimensional conformal radiation therapy and < 5% for intensity-modulated radiation therapy (IMRT with CT parameters. It could be concluded that CT number variability is dependent on acquisition parameters, but its dosimetric impact is pronounced only in high-density media and possibly in IMRT. In view of such small dosimetric changes in low-density medium, the acquisition of additional CT data for financially difficult clinics and countries may not be warranted.

  12. Coronary computed tomography angiography - Tolerability of β-blockers and contrast media, and temporal changes in radiation dose

    DEFF Research Database (Denmark)

    Pedersen, Charlotte; Thomsen, Camilla F; Hosbond, Susanne Elisabeth

    2014-01-01

    Abstract Objective: To determine the risk of administration of β-blockers, contrast induced nephropathy (CIN) and trend in x-rays use, during coronary computed tomography angiography (CCTA). Methods: A total of 416 patients were referred for elective CCTA. To achieve a resting heart rate below 60.......0001. Conclusions: In terms of side effects to β-blockers and contrast media, there were no short term complications to CCTA. Furthermore the radiation dose was dramatically diminished over the last three years....

  13. Computed tomography as a source of electron density information for radiation treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Skrzynski, Witold; Slusarczyk-Kacprzyk, Wioletta; Bulski, Wojciech [Medical Physics Dept., Center of Oncology, Warsaw (Poland); Zielinska-Dabrowska, Sylwia; Wachowicz, Marta; Kukolowicz, Pawel F. [Medical Physics Dept., Holycross Cancer Center, Kielce (Poland)

    2010-06-15

    Purpose: to evaluate the performance of computed tomography (CT) systems of various designs as a source of electron density ({rho}{sub el}) data for treatment planning of radiation therapy. Material and methods: dependence of CT numbers on relative electron density of tissue-equivalent materials (HU-{rho}{sub el} relationship) was measured for several general-purpose CT systems (single-slice, multislice, wide-bore multislice), for radiotherapy simulators with a single-slice CT and kV CBCT (cone-beam CT) options, as well as for linear accelerators with kV and MV CBCT systems. Electron density phantoms of four sizes were used. Measurement data were compared with the standard HU-{rho}{sub el} relationships predefined in two commercial treatment-planning systems (TPS). Results: the HU-{rho}{sub el} relationships obtained with all of the general-purpose CT scanners operating at voltages close to 120 kV were very similar to each other and close to those predefined in TPS. Some dependency of HU values on tube voltage was observed for bone-equivalent materials. For a given tube voltage, differences in results obtained for different phantoms were larger than those obtained for different CT scanners. For radiotherapy simulators and for kV CBCT systems, the information on {rho}{sub el} was much less precise because of poor uniformity of images. For MV CBCT, the results were significantly different than for kV systems due to the differing energy spectrum of the beam. Conclusion: the HU-{rho}{sub el} relationships predefined in TPS can be used for general-purpose CT systems operating at voltages close to 120 kV. For nontypical imaging systems (e.g., CBCT), the relationship can be significantly different and, therefore, it should always be measured and carefully analyzed before using CT data for treatment planning. (orig.)

  14. Ionizing radiation doses during lower limb torsion and anteversion measurements by EOS stereoradiography and computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Delin, Cyrille, E-mail: cdelin@maunol.fr [Réseau d’Imagerie Médicale Maussins-Nollet, 114 rue Nollet, 75017 Paris (France); Silvera, Stéphane, E-mail: stephane.silvera@gmail.com [Service de Radiologie A, Hôpital Cochin, 27 rue du Faubourg Saint Jacques, 75014 Paris (France); Bassinet, Céline, E-mail: celine.bassinet@irsn.fr [Institut de Radioprotection et de Sureté Nucléaire, BP 17, 31 Avenue de la Division Leclerc, 92262 Fontenay-aux-Roses Cedex (France); Thelen, Philippe, E-mail: pthelen@maunol.fr [Réseau d’Imagerie Médicale Maussins-Nollet, 114 rue Nollet, 75017 Paris (France); Rehel, Jean-Luc, E-mail: jean-luc.rehel@irsn.fr [Institut de Radioprotection et de Sureté Nucléaire, BP 17, 31 Avenue de la Division Leclerc, 92262 Fontenay-aux-Roses Cedex (France); Legmann, Paul, E-mail: paul.legmann@cch.aphp.fr [Service de Radiologie A, Hôpital Cochin, 27 rue du Faubourg Saint Jacques, 75014 Paris (France); Folinais, Dominique, E-mail: dfolinais@gmail.com [Réseau d’Imagerie Médicale Maussins-Nollet, 114 rue Nollet, 75017 Paris (France)

    2014-02-15

    Objectives: To calculate and compare the doses of ionizing radiation delivered to the organs by computed tomography (CT) and stereoradiography (SR) during measurements of lower limb torsion and anteversion. Materials and methods: A Rando anthropomorphic phantom (Alderson RANDO phantom, Alderson Research Laboratories Inc., Stanford, Conn) was used for the dose measurements. The doses were delivered by a Somatom 16-slice CT-scanner (Siemens, Erlangen) and an EOS stereoradiography unit (EOS-Imaging, Paris) according to the manufacturers’ acquisition protocols. Doses to the surface and deeper layers were calculated with thermoluminiscent GR207P dosimeters. Dose uncertainties were evaluated and assessed at 6% at k = 2 (that is, two standard deviations). Results: The absorbed doses for the principal organs assessed were as follows: for the ovaries, 0.1 mGy to the right ovary and 0.5 mGy to the left ovary with SR versus1.3 mGy and 1.1 mGy with CT, respectively; testes, 0.3 mGy on the right and 0.4 mGy on the left with SR versus 8.5 mGy and 8.4 mGy with CT; knees, 0.4 mGy to the right knee and 0.8 mGy to the left knee with SR versus 11 mGy and 10.4 mGy with CT; ankles, 0.5 mGy to the right ankle and 0.8 mGy to the left with SR versus 15 mGy with CT. Conclusion: The SR system delivered substantially lower doses of ionizing radiation doses than CT to all the organs studied: CT doses were 4.1 times higher to the ovaries, 24 times higher for the testicles, and 13–30 times higher for the knees and ankles. The use of the SR system to study the torsion of lower limbs makes it possible to reduce the amount of medical irradiation that patients accumulate.

  15. Computed Tomography Scan and ICD Interaction

    Directory of Open Access Journals (Sweden)

    Jose M. Porres

    2009-01-01

    Full Text Available Although it has been considered a safe procedure, computed tomography scanning uses high doses of radiation and can cause malfunctioning in those patients with ICD when the radiation is directly incident on the device. We present a case of ventricular oversensing during a thoracic computed tomography.

  16. Iterative Reconstruction for Cardiopulmonary Computed Tomography

    NARCIS (Netherlands)

    Willemink, M.J.

    2015-01-01

    Introduction The number of computed tomography (CT) examinations has increased rapidly since CT became commercially available. This resulted in growing concerns regarding the risk of malignancies induced by application of medical ionizing radiation. Therefore, radiation dose reduction strategies

  17. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... are the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed ... nasal cavity by small openings. top of page What are some common uses of the procedure? CT ...

  18. Estimation of the radiation exposure of a chest pain protocol with ECG-gating in dual-source computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ketelsen, Dominik; Luetkhoff, Marie H.; Thomas, Christoph; Werner, Matthias; Tsiflikas, Ilias; Reimann, Anja; Kopp, Andreas F.; Claussen, Claus D.; Heuschmid, Martin [University Hospital Tuebingen, Eberhard-Karls-University, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Buchgeister, Markus [University Hospital, Department of Radiotherapy and Radiooncology, Tuebingen (Germany); Burgstahler, Christof [University Hospital Tuebingen, Department of Cardiology, Tuebingen (Germany)

    2009-01-15

    The aim of the study was to evaluate radiation exposure of a chest pain protocol with ECG-gated dual-source computed tomography (DSCT). An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for dose measurements. Exposure was performed on a dual-source computed tomography system with a standard protocol for chest pain evaluation (120 kV, 320 mAs/rot) with different simulated heart rates (HRs). The dose of a standard chest CT examination (120 kV, 160 mAs) was also measured. Effective dose of the chest pain protocol was 19.3/21.9 mSv (male/female, HR 60), 17.9/20.4 mSv (male/female, HR 80) and 14.7/16.7 mSv (male/female, HR 100). Effective dose of a standard chest examination was 6.3 mSv (males) and 7.2 mSv (females). Radiation dose of the chest pain protocol increases significantly with a lower heart rate for both males (p = 0.040) and females (p = 0.044). The average radiation dose of a standard chest CT examination is about 36.5% that of a CT examination performed for chest pain. Using DSCT, the evaluated chest pain protocol revealed a higher radiation exposure compared with standard chest CT. Furthermore, HRs markedly influenced the dose exposure when using the ECG-gated chest pain protocol. (orig.)

  19. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... are the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside of ...

  20. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known as a ... top of page What are some common uses of the procedure? CT of the sinuses is primarily ...

  1. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, air-filled spaces within the bones of ...

  2. Reduction of radiation dose of computed tomography in children with traumatic brain injury does not compromise the diagnosis and medical conduct

    Directory of Open Access Journals (Sweden)

    Mônica de Oliveira Bernardo

    2017-01-01

    Full Text Available Introduction: The worldwide increases in availability and request of computed tomography in children have brought concern about the cumulative effect of radiation. Traumatic brain injury is a clinical situation in which tomography is frequently necessary. Objectives: 1. Evaluating if the reduction of the radiation dose of head computed tomography in children with head trauma would affect the diagnosis and medical conduct; 2. Promoting a radioprotection campaign in a private health care system. Method: We selected two groups of computed tomography from children with head trauma: 30 performed before the study period, with usual doses of radiation; and 30 tomographies performed during the project, in which we applied the protocol of The Radiation Safety The Alliance for Imaging in Pediatric with 50% radiation dose reduction. The two series of exams were presented to 19 pediatricians, 2 neurosurgeons and 7 radiologists who were unaware of the technical differences and they answered a questionnaire. Results: The professionals had no difficulty in making a diagnosis and establish a conduct with both series of exams. Four participants noted more grainy images in the exams with lower radiation dose. A radioprotection campaign distributed 17,000 radioprotection wallets for children up to 12 years. Professionals involved and parents joined the campaign strongly and rationally. Conclusions: It is possible to reduce the computed tomography radiation dose for children with head trauma without any prejudice to the diagnosis and treatment. The radioprotection campaign was effective and well accepted by professionals and family and will become a national campaign.

  3. Computed Tomography (CT) -- Head

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    Full Text Available ... Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear ... or other physician. To locate a medical imaging or radiation oncology provider in your community, you can search the ...

  4. Development of a Radiation Dose Reporting Software for X-ray Computed Tomography (CT)

    Science.gov (United States)

    Ding, Aiping

    X-ray computed tomography (CT) has experienced tremendous technological advances in recent years and has established itself as one of the most popular diagnostic imaging tools. While CT imaging clearly plays an invaluable role in modern medicine, its rapid adoption has resulted in a dramatic increase in the average medical radiation exposure to the worldwide and United States populations. Existing software tools for CT dose estimation and reporting are mostly based on patient phantoms that contain overly simplified anatomies insufficient in meeting the current and future needs. This dissertation describes the development of an easy-to-use software platform, “VirtualDose”, as a service to estimate and report the organ dose and effective dose values for patients undergoing the CT examinations. “VirtualDose” incorporates advanced models for the adult male and female, pregnant women, and children. To cover a large portion of the ignored obese patients that frequents the radiology clinics, a new set of obese male and female phantoms are also developed and applied to study the effects of the fat tissues on the CT radiation dose. Multi-detector CT scanners (MDCT) and clinical protocols, as well as the most recent effective dose algorithms from the International Commission on Radiological Protection (ICRP) Publication 103 are adopted in “VirtualDose” to keep pace with the MDCT development and regulatory requirements. A new MDCT scanner model with both body and head bowtie filter is developed to cover both the head and body scanning modes. This model was validated through the clinical measurements. A comprehensive slice-by-slice database is established by deriving the data from a larger number of single axial scans simulated on the patient phantoms using different CT bowtie filters, beam thicknesses, and different tube voltages in the Monte Carlo N-Particle Extended (MCNPX) code. When compared to the existing CT dose software packages, organ dose data in this

  5. Image Registration of Cone-Beam Computer Tomography and Preprocedural Computer Tomography Aids in Localization of Adrenal Veins and Decreasing Radiation Dose in Adrenal Vein Sampling

    Energy Technology Data Exchange (ETDEWEB)

    Busser, Wendy M. H., E-mail: wendy.busser@radboudumc.nl; Arntz, Mark J.; Jenniskens, Sjoerd F. M. [Radboud University Medical Center, Department of Radiology, Section of Interventional Radiology (Netherlands); Deinum, Jaap [Radboud University Medical Center, Department of General Internal Medicine (Netherlands); Hoogeveen, Yvonne L.; Lange, Frank de; Schultze Kool, Leo J. [Radboud University Medical Center, Department of Radiology, Section of Interventional Radiology (Netherlands)

    2015-08-15

    PurposeWe assessed whether image registration of cone-beam computed tomography (CT) (CBCT) and contrast-enhanced CT (CE-CT) images indicating the locations of the adrenal veins can aid in increasing the success rate of first-attempts adrenal vein sampling (AVS) and therefore decreasing patient radiation dose.Materials and Methods CBCT scans were acquired in the interventional suite (Philips Allura Xper FD20) and rigidly registered to the vertebra in previously acquired CE-CT. Adrenal vein locations were marked on the CT image and superimposed with live fluoroscopy and digital-subtraction angiography (DSA) to guide the AVS. Seventeen first attempts at AVS were performed with image registration and retrospectively compared with 15 first attempts without image registration performed earlier by the same 2 interventional radiologists. First-attempt AVS was considered successful when both adrenal vein samples showed representative cortisol levels. Sampling time, dose-area product (DAP), number of DSA runs, fluoroscopy time, and skin dose were recorded.ResultsWithout image registration, the first attempt at sampling was successful in 8 of 15 procedures indicating a success rate of 53.3 %. This increased to 76.5 % (13 of 17) by adding CBCT and CE-CT image registration to AVS procedures (p = 0.266). DAP values (p = 0.001) and DSA runs (p = 0.026) decreased significantly by adding image registration guidance. Sampling and fluoroscopy times and skin dose showed no significant changes.ConclusionGuidance based on registration of CBCT and previously acquired diagnostic CE-CT can aid in enhancing localization of the adrenal veins thereby increasing the success rate of first-attempt AVS with a significant decrease in the number of used DSA runs and, consequently, radiation dose required.

  6. Radiation therapy for intracranial germ cell tumors. Predictive value of tumor response as evaluated by computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Kazuhiko; Toita, Takafumi; Kakinohana, Yasumasa; Yamaguchi, Keiichiro; Miyagi, Koichi; Kinjo, Toshihiko; Yamashiro, Katsumi; Sawada, Satoshi [Ryukyu Univ., Nishihara, Okinawa (Japan). School of Medicine

    1997-07-01

    This retrospective study analyzed the outcome in patients with intracranial germ-cell tumors to determine whether tumor response during radiation therapy can predict achievement of primary local with radiation therapy alone. Between 1983 and 1993, 22 patients with untreated primary intracranial germ cell tumors received a total whole brain radiation dose of between 18 Gy and 45 Gy (mean 31.3 Gy) with or without a localized field of 10 to 36.4 Gy (mean, 22.4 Gy), or local irradiation only (1 patient). In 10 patients with pineal tumor only, who were treated first with radiation therapy, tumor response to radiation therapy was evaluated using computed tomography (CT) (at baseline, and approximately 20 Gy and 50 Gy). Areas of calcification in the tumor were subtracted from total tumor volume. Follow-up time ranged from 2 to 12 years. Five-year actuarial survival rates for patients with germinoma were 71%, 100% for patients with a teratoma component, and 100% for patients without histologic verification. Patients with germinomas or tumors suspected of being germinomas who were given more than 50 Gy had no local relapse. There was no correlation between primary local control by radiation therapy alone and initial tumor volume. The rate of tumor volume response to irradiation assessed by CT was significantly different in those patients who relapsed compared to those who did not relapse. Tumor response during radiation therapy using CT was considered to be predictive of primary local control with radiation therapy alone. (author)

  7. Clinical Implementation of Intrafraction Cone Beam Computed Tomography Imaging During Lung Tumor Stereotactic Ablative Radiation Therapy

    Science.gov (United States)

    Li, Ruijiang; Han, Bin; Meng, Bowen; Maxim, Peter G.; Xing, Lei; Koong, Albert C.; Diehn, Maximilian; Loo, Billy W.

    2013-01-01

    Purpose To develop and clinically evaluate a volumetric imaging technique for assessing intrafraction geometric and dosimetric accuracy of stereotactic ablative radiation therapy (SABR). Methods and Materials Twenty patients received SABR for lung tumors using volumetric modulated arc therapy (VMAT). At the beginning of each fraction, pretreatment cone beam computed tomography (CBCT) was used to align the soft-tissue tumor position with that in the planning CT. Concurrent with dose delivery, we acquired fluoroscopic radiograph projections during VMAT using the Varian on-board imaging system. Those kilovolt projections acquired during megavolt beam-on were automatically extracted, and intrafraction CBCT images were reconstructed using the filtered backprojection technique. We determined the time-averaged target shift during VMAT by calculating the center of mass of the tumor target in the intrafraction CBCT relative to the planning CT. To estimate the dosimetric impact of the target shift during treatment, we recalculated the dose to the GTV after shifting the entire patient anatomy according to the time-averaged target shift determined earlier. Results The mean target shift from intrafraction CBCT to planning CT was 1.6, 1.0, and 1.5 mm; the 95th percentile shift was 5.2, 3.1, 3.6 mm; and the maximum shift was 5.7, 3.6, and 4.9 mm along the anterior-posterior, left-right, and superior-inferior directions. Thus, the time-averaged intrafraction gross tumor volume (GTV) position was always within the planning target volume. We observed some degree of target blurring in the intrafraction CBCT, indicating imperfect breath-hold reproducibility or residual motion of the GTV during treatment. By our estimated dose recalculation, the GTV was consistently covered by the prescription dose (PD), that is, V100% above 0.97 for all patients, and minimum dose to GTV >100% PD for 18 patients and >95% PD for all patients. Conclusions Intrafraction CBCT during VMAT can provide

  8. Optimization of Computed Tomography Urography Protocol, 1997 to 2008: Effects on Radiation Dose

    Energy Technology Data Exchange (ETDEWEB)

    Dahlman, P.; Segelsjoe, M.; Magnusson, A. (Dept. of Radiology, Uppsala Univ. Hospital, Uppsala (Sweden)); Jangland, L. (Dept. of Medical Physics, Uppsala Univ. Hospital, Uppsala (Sweden))

    2009-05-15

    Background: Since computed tomography (CT) urography began to replace excretory urography as the primary imaging technique in uroradiology, the collective radiation dose to the patients has increased. Purpose: To examine the changes in the CT urography protocol for investigating suspected urinary tract malignancy between the years 1997 and 2008, and how these changes have influenced the mean effective dose. Material and Methods: The study was based on 102 patients (mean age 66.1+-14.8 years, range 31-89 years; 30 female, 72 male) divided into five groups (groups A-E) corresponding to the time points at which changes were made to the CT urography protocol. The mean effective doses were estimated using the ImPACT CT Patient Dosimetry Calculator. Results: The number of scan phases at CT urography was reduced from four to three in 1999, resulting in a reduction of the mean effective dose from 29.9/22.5 (female [F]/male [M]) mSv (group A) to 26.1/18.9 (F/M) mSv (group B). In 2001, mAs settings were adapted to patient size, and the mean effective dose was reduced to 16.8/12.0 (F/M) mSv (group C). In 2005, scans were performed with a multidetector-row CT equipped with automatic tube current modulation in the x- and y-axis (CARE Dose). The effective mAs was also lowered in the unenhanced and excretory phase, yet the mean effective dose increased to 18.2/13.1 (F/M) mSv (group D), since the effective mAs had to be increased in the corticomedullary phase to maintain image quality. In 2008, as tube current modulation in the x-, y-, and z-axis was introduced (CARE Dose4D), the mean effective dose was reduced to 11.7/8.8 (F/M) mSv (group E). Conclusion: This study shows that the individual mean effective dose to patients undergoing CT urography has decreased by 60%, from 29.9/22.5 (F/M) mSv in 1997 to 11.7/8.8 (F/M) mSv in 2008.

  9. Optimization of computed tomography urography protocol, 1997 to 2008: effects on radiation dose.

    Science.gov (United States)

    Dahlman, P; Jangland, L; Segelsjö, M; Magnusson, A

    2009-05-01

    Since computed tomography (CT) urography began to replace excretory urography as the primary imaging technique in uroradiology, the collective radiation dose to the patients has increased. To examine the changes in the CT urography protocol for investigating suspected urinary tract malignancy between the years 1997 and 2008, and how these changes have influenced the mean effective dose. The study was based on 102 patients (mean age 66.1+/-14.8 years, range 31-89 years; 30 female, 72 male) divided into five groups (groups A-E) corresponding to the time points at which changes were made to the CT urography protocol. The mean effective doses were estimated using the ImPACT CT Patient Dosimetry Calculator. The number of scan phases at CT urography was reduced from four to three in 1999, resulting in a reduction of the mean effective dose from 29.9/22.5 (female [F]/male [M]) mSv (group A) to 26.1/18.9 (F/M) mSv (group B). In 2001, mAs settings were adapted to patient size, and the mean effective dose was reduced to 16.8/12.0 (F/M) mSv (group C). In 2005, scans were performed with a multidetector-row CT equipped with automatic tube current modulation in the x- and y-axis (CARE Dose). The effective mAs was also lowered in the unenhanced and excretory phase, yet the mean effective dose increased to 18.2/13.1 (F/M) mSv (group D), since the effective mAs had to be increased in the corticomedullary phase to maintain image quality. In 2008, as tube current modulation in the x-, y-, and z-axis was introduced (CARE Dose4D), the mean effective dose was reduced to 11.7/8.8 (F/M) mSv (group E). This study shows that the individual mean effective dose to patients undergoing CT urography has decreased by 60%, from 29.9/22.5 (F/M) mSv in 1997 to 11.7/8.8 (F/M) mSv in 2008.

  10. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) ... are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a ...

  11. Estimating radiation effective doses from whole body computed tomography scans based on U.S. soldier patient height and weight

    Directory of Open Access Journals (Sweden)

    Quinn Brian

    2011-10-01

    Full Text Available Abstract Background The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose. Methods One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population. Results Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters. Conclusions A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques.

  12. Phase 1-2 Study of Dual-Energy Computed Tomography for Assessment of Pulmonary Function in Radiation Therapy Planning.

    Science.gov (United States)

    Bahig, Houda; Campeau, Marie-Pierre; Lapointe, Andréanne; Bedwani, Stephane; Roberge, David; de Guise, Jacques; Blais, Danis; Vu, Toni; Lambert, Louise; Chartrand-Lefebvre, Carl; Lord, Martin; Filion, Edith

    2017-10-01

    To quantify lung function according to a dual-energy computed tomography (DECT)-derived iodine map in patients treated with radiation therapy for lung cancer, and to assess the dosimetric impact of its integration in radiation therapy planning. Patients treated with stereotactic ablative radiation therapy for early-stage or intensity modulated radiation therapy for locally advanced lung cancer were prospectively enrolled in this study. A DECT in treatment position was obtained at time of treatment planning. The relative contribution of each voxel to the total lung function was based on iodine distribution. The composition of each voxel was determined on the basis of a 2-material decomposition. The DECT-derived lobar function was compared with single photon emission computed tomography/computed tomography (SPECT/CT). A functional map was integrated in the treatment planning system using 6 subvolumes of increasing iodine distribution levels. Percent lung volume receiving 5 Gy (V5), V20, and mean dose (MLD) to whole lungs (anatomic) versus functional lungs were compared. Twenty-five patients with lung cancer, including 18 patients treated with stereotactic ablative radiation therapy and 7 patients with intensity modulated radiation therapy (locally advanced), were included. Eighty-four percent had chronic obstructive pulmonary disease. Median (range) forced expiratory volume in 1 second was 62% of predicted (29%-113%), and median diffusing capacity of the lung for carbon monoxide was 56% (39%-91%). There was a strong linear correlation between DECT- and SPECT/CT-derived lobar function (Pearson coefficient correlation r=0.89, P<.00001). Mean (range) differences in V5, V20, and MLD between anatomic and functional lung volumes were 16% (0%-48%, P=.03), 5% (1%-15%, P=.12), and 15% (1%-43%, P=.047), respectively. Lobar function derived from a DECT iodine map correlates well with SPECT/CT, and its integration in lung treatment planning is associated with significant

  13. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, air-filled spaces within the bones of the face surrounding the ...

  14. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, ... than regular radiographs (x-rays). top of page What are some common uses of the procedure? CT ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... story about radiology? Share your patient story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View ... possible charges you will incur. Web page review process: This Web page is reviewed regularly by a ...

  16. Computed Tomography (CT) -- Head

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    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  17. Radiation doses in volume-of-interest breast computed tomography--A Monte Carlo simulation study.

    Science.gov (United States)

    Lai, Chao-Jen; Zhong, Yuncheng; Yi, Ying; Wang, Tianpeng; Shaw, Chris C

    2015-06-01

    Cone beam breast computed tomography (breast CT) with true three-dimensional, nearly isotropic spatial resolution has been developed and investigated over the past decade to overcome the problem of lesions overlapping with breast anatomical structures on two-dimensional mammographic images. However, the ability of breast CT to detect small objects, such as tissue structure edges and small calcifications, is limited. To resolve this problem, the authors proposed and developed a volume-of-interest (VOI) breast CT technique to image a small VOI using a higher radiation dose to improve that region's visibility. In this study, the authors performed Monte Carlo simulations to estimate average breast dose and average glandular dose (AGD) for the VOI breast CT technique. Electron-Gamma-Shower system code-based Monte Carlo codes were used to simulate breast CT. The Monte Carlo codes estimated were validated using physical measurements of air kerma ratios and point doses in phantoms with an ion chamber and optically stimulated luminescence dosimeters. The validated full cone x-ray source was then collimated to simulate half cone beam x-rays to image digital pendant-geometry, hemi-ellipsoidal, homogeneous breast phantoms and to estimate breast doses with full field scans. 13-cm in diameter, 10-cm long hemi-ellipsoidal homogeneous phantoms were used to simulate median breasts. Breast compositions of 25% and 50% volumetric glandular fractions (VGFs) were used to investigate the influence on breast dose. The simulated half cone beam x-rays were then collimated to a narrow x-ray beam with an area of 2.5 × 2.5 cm(2) field of view at the isocenter plane and to perform VOI field scans. The Monte Carlo results for the full field scans and the VOI field scans were then used to estimate the AGD for the VOI breast CT technique. The ratios of air kerma ratios and dose measurement results from the Monte Carlo simulation to those from the physical measurements were 0.97 ± 0.03 and 1.10

  18. Image Guided Radiation Therapy Using Synthetic Computed Tomography Images in Brain Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Price, Ryan G. [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan (United States); Kim, Joshua P.; Zheng, Weili [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Chetty, Indrin J. [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan (United States); Glide-Hurst, Carri, E-mail: churst2@hfhs.org [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Department of Radiation Oncology, Wayne State University School of Medicine, Detroit, Michigan (United States)

    2016-07-15

    Purpose: The development of synthetic computed tomography (CT) (synCT) derived from magnetic resonance (MR) images supports MR-only treatment planning. We evaluated the accuracy of synCT and synCT-generated digitally reconstructed radiographs (DRRs) relative to CT and determined their performance for image guided radiation therapy (IGRT). Methods and Materials: Magnetic resonance simulation (MR-SIM) and CT simulation (CT-SIM) images were acquired of an anthropomorphic skull phantom and 12 patient brain cancer cases. SynCTs were generated using fluid attenuation inversion recovery, ultrashort echo time, and Dixon data sets through a voxel-based weighted summation of 5 tissue classifications. The DRRs were generated from the phantom synCT, and geometric fidelity was assessed relative to CT-generated DRRs through bounding box and landmark analysis. An offline retrospective analysis was conducted to register cone beam CTs (n=34) to synCTs and CTs using automated rigid registration in the treatment planning system. Planar MV and KV images (n=37) were rigidly registered to synCT and CT DRRs using an in-house script. Planar and volumetric registration reproducibility was assessed and margin differences were characterized by the van Herk formalism. Results: Bounding box and landmark analysis of phantom synCT DRRs were within 1 mm of CT DRRs. Absolute planar registration shift differences ranged from 0.0 to 0.7 mm for phantom DRRs on all treatment platforms and from 0.0 to 0.4 mm for volumetric registrations. For patient planar registrations, the mean shift differences were 0.4 ± 0.5 mm (range, −0.6 to 1.6 mm), 0.0 ± 0.5 mm (range, −0.9 to 1.2 mm), and 0.1 ± 0.3 mm (range, −0.7 to 0.6 mm) for the superior-inferior (S-I), left-right (L-R), and anterior-posterior (A-P) axes, respectively. The mean shift differences in volumetric registrations were 0.6 ± 0.4 mm (range, −0.2 to 1.6 mm), 0.2 ± 0.4 mm (range, −0.3 to 1.2 mm), and 0.2 ± 0

  19. Quantifying morphological parameters of the terminal branching units in a mouse lung by phase contrast synchrotron radiation computed tomography.

    Directory of Open Access Journals (Sweden)

    Jeongeun Hwang

    Full Text Available An effective technique of phase contrast synchrotron radiation computed tomography was established for the quantitative analysis of the microstructures in the respiratory zone of a mouse lung. Heitzman's method was adopted for the whole-lung sample preparation, and Canny's edge detector was used for locating the air-tissue boundaries. This technique revealed detailed morphology of the respiratory zone components, including terminal bronchioles and alveolar sacs, with sufficiently high resolution of 1.74 µm isotropic voxel size. The technique enabled visual inspection of the respiratory zone components and comprehension of their relative positions in three dimensions. To check the method's feasibility for quantitative imaging, morphological parameters such as diameter, surface area and volume were measured and analyzed for sixteen randomly selected terminal branching units, each consisting of a terminal bronchiole and a pair of succeeding alveolar sacs. The four types of asymmetry ratios concerning alveolar sac mouth diameter, alveolar sac surface area, and alveolar sac volume are measured. This is the first ever finding of the asymmetry ratio for the terminal bronchioles and alveolar sacs, and it is noteworthy that an appreciable degree of branching asymmetry was observed among the alveolar sacs at the terminal end of the airway tree, despite the number of samples was small yet. The series of efficient techniques developed and confirmed in this study, from sample preparation to quantification, is expected to contribute to a wider and exacter application of phase contrast synchrotron radiation computed tomography to a variety of studies.

  20. [The radiation dose problem in computed tomography. Actual data and strategies for a corrected use of ionizing radiation in computed tomography].

    Science.gov (United States)

    Gualdi, G F; Bertini, L; Lanciotti, S; Colaiacomo, M C; Campagnano, S; Polettini, E

    2008-01-01

    New technologies in these years has taken to a spread and to a growth of the CT application with an increase of patients and population exposure. In clinical practice some technical devices can be used to reduce the exposure dose of multidetector CT that allows radiologist to answer the clinical question with less damage to the patient. The radiologist remains however the guarantor of the ionizing radiation exposition and he has to consider also the opportunity to use other methodics (MR, US) to answer some questions. The radiologist has the role to evaluate the clinical indication to the exam demanded from other doctor and has the responsibility for exam management and for progressive radiologic course, controls and follow-up.

  1. Radiation doses in cone-beam breast computed tomography: A Monte Carlo simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Yi Ying; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Shen Youtao; Liu Xinming; Ge Shuaiping; You Zhicheng; Wang Tianpeng; Shaw, Chris C. [Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2011-02-15

    Purpose: In this article, we describe a method to estimate the spatial dose variation, average dose and mean glandular dose (MGD) for a real breast using Monte Carlo simulation based on cone beam breast computed tomography (CBBCT) images. We present and discuss the dose estimation results for 19 mastectomy breast specimens, 4 homogeneous breast models, 6 ellipsoidal phantoms, and 6 cylindrical phantoms. Methods: To validate the Monte Carlo method for dose estimation in CBBCT, we compared the Monte Carlo dose estimates with the thermoluminescent dosimeter measurements at various radial positions in two polycarbonate cylinders (11- and 15-cm in diameter). Cone-beam computed tomography (CBCT) images of 19 mastectomy breast specimens, obtained with a bench-top experimental scanner, were segmented and used to construct 19 structured breast models. Monte Carlo simulation of CBBCT with these models was performed and used to estimate the point doses, average doses, and mean glandular doses for unit open air exposure at the iso-center. Mass based glandularity values were computed and used to investigate their effects on the average doses as well as the mean glandular doses. Average doses for 4 homogeneous breast models were estimated and compared to those of the corresponding structured breast models to investigate the effect of tissue structures. Average doses for ellipsoidal and cylindrical digital phantoms of identical diameter and height were also estimated for various glandularity values and compared with those for the structured breast models. Results: The absorbed dose maps for structured breast models show that doses in the glandular tissue were higher than those in the nearby adipose tissue. Estimated average doses for the homogeneous breast models were almost identical to those for the structured breast models (p=1). Normalized average doses estimated for the ellipsoidal phantoms were similar to those for the structured breast models (root mean square (rms

  2. Assessing lung function using contrast-enhanced dual-energy computed tomography for potential applications in radiation therapy.

    Science.gov (United States)

    Lapointe, Andréanne; Bahig, Houda; Blais, Danis; Bouchard, Hugo; Filion, Édith; Carrier, Jean-François; Bedwani, Stéphane

    2017-10-01

    There is an increasing interest in the evaluation of lung function from physiological images in radiation therapy treatment planning to reduce the extent of postradiation toxicities. The purpose of this work was to retrieve reliable functional information from contrast-enhanced dual-energy computed tomography (DECT) for new applications in radiation therapy. The functional information obtained by DECT is also compared with other methods using single-energy CT (SECT) and single-photon emission computed tomography (SPECT) with CT. The differential function between left and right lung, as well as between lobes is computed for all methods. Five lung cancer patients were retrospectively selected for this study; each underwent a SPECT/CT scan and a contrast-injected DECT scan, using 100 and 140 Sn kVp. The DECT images are postprocessed into iodine concentration maps, which are further used to determine the perfused blood volume. These maps are calculated in two steps: (a) a DECT stoichiometric calibration adapted to the presence of iodine and followed by (b) a two-material decomposition technique. The functional information from SECT is assumed proportional to the HU numbers from a mixed CT image. The functional data from SPECT/CT are considered proportional to the number of counts. A radiation oncologist segmented the entire lung volume into five lobes on both mixed CT images and low-dose CT images from SPECT/CT to allow a regional comparison. The differential function for each subvolume is computed relative to the entire lung volume. The differential function per lobe derived from SPECT/CT correlates strongly with DECT (Pearson's coefficient r = 0.91) and moderately with SECT (r = 0.46). The differential function for the left lung shows a mean difference of 7% between SPECT/CT and DECT; and 17% between SPECT/CT and SECT. The presence of nonfunctional areas, such as localized emphysema or a lung tumor, is reflected by an intensity drop in the iodine concentration maps

  3. Impact of Pretreatment Combined {sup 18}F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Staging on Radiation Therapy Treatment Decisions in Locally Advanced Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Sweet Ping, E-mail: sweet.ng@petermac.org [Peter MacCallum Cancer Centre, Melbourne (Australia); David, Steven [Peter MacCallum Cancer Centre, Melbourne (Australia); Alamgeer, Muhammad; Ganju, Vinod [Monash Cancer Centre, Melbourne (Australia)

    2015-09-01

    Purpose: To assess the diagnostic performance of pretreatment {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography ({sup 18}F-FDG PET/CT) and its impact on radiation therapy treatment decisions in patients with locally advanced breast cancer (LABC). Methods and Materials: Patients with LABC with Eastern Cooperative Oncology Group performance status <2 and no contraindication to neoadjuvant chemotherapy, surgery, and adjuvant radiation therapy were enrolled on a prospective trial. All patients had pretreatment conventional imaging (CI) performed, including bilateral breast mammography and ultrasound, bone scan, and CT chest, abdomen, and pelvis scans performed. Informed consent was obtained before enrolment. Pretreatment whole-body {sup 18}F-FDG PET/CT scans were performed on all patients, and results were compared with CI findings. Results: A total of 154 patients with LABC with no clinical or radiologic evidence of distant metastases on CI were enrolled. Median age was 49 years (range, 26-70 years). Imaging with PET/CT detected distant metastatic disease and/or locoregional disease not visualized on CI in 32 patients (20.8%). Distant metastatic disease was detected in 17 patients (11.0%): 6 had bony metastases, 5 had intrathoracic metastases (pulmonary/mediastinal), 2 had distant nodal metastases, 2 had liver metastases, 1 had pulmonary and bony metastases, and 1 had mediastinal and distant nodal metastases. Of the remaining 139 patients, nodal disease outside conventional radiation therapy fields was detected on PET/CT in 15 patients (10.8%), with involvement of ipsilateral internal mammary nodes in 13 and ipsilateral level 5 cervical nodes in 2. Conclusions: Imaging with PET/CT provides superior diagnostic and staging information in patients with LABC compared with CI, which has significant therapeutic implications with respect to radiation therapy management. Imaging with PET/CT should be considered in all patients undergoing primary

  4. Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction

    Science.gov (United States)

    Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

    2017-04-01

    A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

  5. Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction.

    Science.gov (United States)

    Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

    2017-04-21

    A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

  6. Operating room radiation exposure in cone beam computed tomography-based, image-guided spinal surgery: clinical article.

    Science.gov (United States)

    Nottmeier, Eric W; Pirris, Stephen M; Edwards, Steven; Kimes, Sherri; Bowman, Cammi; Nelson, Kevin L

    2013-08-01

    Surgeon and operating room (OR) staff radiation exposure during spinal surgery is a concern, especially with the increasing use of multiplanar fluoroscopy in minimally invasive spinal surgery procedures. Cone beam computed tomography (cbCT)-based, 3D image guidance does not involve the use of active fluoroscopy during instrumentation placement and therefore decreases radiation exposure for the surgeon and OR staff during spinal fusion procedures. However, the radiation scatter of a cbCT device can be similar to that of a standard 64-slice CT scanner and thus could expose the surgeon and OR staff to radiation during image acquisition. The purpose of the present study was to measure radiation exposure at several unshielded locations in the OR when using cbCT in conjunction with 3D image-guided spinal surgery in 25 spinal surgery cases. Five unshielded badge dosimeters were placed at set locations in the OR during 25 spinal surgery cases in which cbCT-based, 3D image guidance was used. The cbCT device (O-ARM) was used in conjunction with the Stealth S7 image-guided platform. The radiology department analyzed the badge dosimeters after completion of the last case. Fifty high-definition O-ARM spins were performed in 25 patients for spinal registration and to check instrumentation placement. Image-guided placement of 124 screws from C-2 to the ileum was accomplished without complication. Badge dosimetry analysis revealed minimal radiation exposure for the badges 6 feet from the gantry in the area of the anesthesiology equipment, as well as for the badges located 10-13 feet from the gantry on each side of the room (mean 0.7-3.6 mrem/spin). The greatest radiation exposure occurred on the badge attached to the OR table within the gantry (mean 176.9 mrem/spin), as well as on the control panel adjacent to the gantry (mean 128.0 mrem/spin). Radiation scatter from the O-ARM was minimal at various distances outside of and not adjacent to the gantry. Although the average

  7. Quantitative computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Judith E. [Royal Infirmary and University, Manchester (United Kingdom)], E-mail: judith.adams@manchester.ac.uk

    2009-09-15

    Quantitative computed tomography (QCT) was introduced in the mid 1970s. The technique is most commonly applied to 2D slices in the lumbar spine to measure trabecular bone mineral density (BMD; mg/cm{sup 3}). Although not as widely utilized as dual-energy X-ray absortiometry (DXA) QCT has some advantages when studying the skeleton (separate measures of cortical and trabecular BMD; measurement of volumetric, as opposed to 'areal' DXA-BMDa, so not size dependent; geometric and structural parameters obtained which contribute to bone strength). A limitation is that the World Health Organisation (WHO) definition of osteoporosis in terms of bone densitometry (T score -2.5 or below using DXA) is not applicable. QCT can be performed on conventional body CT scanners, or at peripheral sites (radius, tibia) using smaller, less expensive dedicated peripheral CT scanners (pQCT). Although the ionising radiation dose of spinal QCT is higher than for DXA, the dose compares favorably with those of other radiographic procedures (spinal radiographs) performed in patients suspected of having osteoporosis. The radiation dose from peripheral QCT scanners is negligible. Technical developments in CT (spiral multi-detector CT; improved spatial resolution) allow rapid acquisition of 3D volume images which enable QCT to be applied to the clinically important site of the proximal femur, more sophisticated analysis of cortical and trabecular bone, the imaging of trabecular structure and the application of finite element analysis (FEA). Such research studies contribute importantly to the understanding of bone growth and development, the effect of disease and treatment on the skeleton and the biomechanics of bone strength and fracture.

  8. Radiation dose reduction in computed tomography (CT) using a new implementation of wavelet denoising in low tube current acquisitions

    Science.gov (United States)

    Tao, Yinghua; Brunner, Stephen; Tang, Jie; Speidel, Michael; Rowley, Howard; VanLysel, Michael; Chen, Guang-Hong

    2011-03-01

    Radiation dose reduction remains at the forefront of research in computed tomography. X-ray tube parameters such as tube current can be lowered to reduce dose; however, images become prohibitively noisy when the tube current is too low. Wavelet denoising is one of many noise reduction techniques. However, traditional wavelet techniques have the tendency to create an artificial noise texture, due to the nonuniform denoising across the image, which is undesirable from a diagnostic perspective. This work presents a new implementation of wavelet denoising that is able to achieve noise reduction, while still preserving spatial resolution. Further, the proposed method has the potential to improve those unnatural noise textures. The technique was tested on both phantom and animal datasets (Catphan phantom and timeresolved swine heart scan) acquired on a GE Discovery VCT scanner. A number of tube currents were used to investigate the potential for dose reduction.

  9. High Atomic Number Contrast Media Offer Potential for Radiation Dose Reduction in Contrast-Enhanced Computed Tomography.

    Science.gov (United States)

    Roessler, Ann-Christin; Hupfer, Martin; Kolditz, Daniel; Jost, Gregor; Pietsch, Hubertus; Kalender, Willi A

    2016-04-01

    Spectral optimization of x-ray computed tomography (CT) has led to substantial radiation dose reduction in contrast-enhanced CT studies using standard iodinated contrast media. The purpose of this study was to analyze the potential for further dose reduction using high-atomic-number elements such as hafnium and tungsten. As in previous studies, spectra were determined for which the patient dose necessary to provide a given contrast-to-noise ratio (CNR) is minimized. We used 2 different quasi-anthropomorphic phantoms representing the liver cross-section of a normal adult and an obese adult patient with the lateral widths of 360 and 460 mm and anterior-posterior heights of 200 and 300 mm, respectively. We simulated and measured on 2 different scanners with x-ray spectra from 80 to 140 kV and from 70 to 150 kV, respectively. We determined the contrast for iodine-, hafnium-, and tungsten-based contrast media, the noise, and 3-dimensional dose distributions at all available tube voltages by measurements and by simulations. The dose-weighted CNR was determined as optimization parameter. Simulations and measurements were in good agreement regarding their dependence on energy for all parameters investigated. Hafnium provided the best performance for normal and for obese patient phantoms, indicating a dose reduction potential of 30% for normal and 50% for obese patients at 120 kV compared with iodine; this advantage increased further with higher kV values. Dose-weighted CNR values for tungsten were always slightly below the hafnium results. Iodine proved to be the superior choice at voltage values of 80 kV and below. Hafnium and tungsten both seem to be candidates for contrast-medium-enhanced CT of normal and obese adult patients with strongly reduced radiation dose at unimpaired image quality. Computed tomography examinations of obese patients will decrease in dose for higher kV values.

  10. Coronary computed tomography angiography - tolerability of β-blockers and contrast media, and temporal changes in radiation dose.

    Science.gov (United States)

    Pedersen, Charlotte; Thomsen, Camilla F; Hosbond, Susanne E; Thomassen, Anders; Mickley, Hans; Diederichsen, Axel C P

    2014-10-01

    To determine the risk in administering β-blockers, contrast-induced nephropathy (CIN) and the trend in X-ray use, during coronary computed tomography angiography (CCTA). A total of 416 patients were referred for elective CCTA. To achieve a resting heart rate below 60 beats per minute, oral and/or intravenous β-blockers were administered. Using questionnaires, information on the adverse effects of β-blockers was collected from the patients. The levels of s-creatinine and estimated GFR (eGFR) were measured before and after contrast enhanced CCTA. Radiation exposure was compared with the exposure 3 years earlier. There was no significant difference in the symptoms (dizziness, lipothymia and palpitations) between patients with and patients without β-blocker pretreatment. Compared to baseline values, the decrease in s-creatinine was not significant (75.2 vs. 74.6 μmol/L, p = 0.09), while the increase in eGFR was not significant (78 vs. 79 mL/min, p = 0.17). Also, subgroups of patients with hypertension, hypercholesterolemia, diabetes or pre-existing slight impairment in renal function did not develop CIN. The mean radiation exposure decreased from 17.5 to 6.7 mSv, p < 0.0001. In terms of the side effects of β-blockers and contrast media, there were no short term complications to CCTA. Furthermore, the radiation dose has been dramatically diminished over the last three years.

  11. Prospectively gated coronary computed tomography angiography: uncompromised quality with markedly reduced radiation exposure in acute chest pain evaluation.

    Science.gov (United States)

    Goitein, Orly; Beigel, Roy; Matetzky, Shlomi; Kuperstein, Rafael; Brosh, Sella; Eshet, Yael; Di Segni, Elio; Konen, Eli

    2011-08-01

    Coronary computed tomography angiography (CCTA) is an established modality for ruling out coronary artery disease. However, it has been suggested that CCTA may be a source of non-negligible radiation exposure. To evaluate the potential degradation in coronary image quality when using prospective gated (PG) CCTA as compared with retrospective gated (RG) CCTA in chest pain evaluation. The study cohort comprised 216 patients: 108 consecutive patients in the PG CCTA arm and 108 patients matched for age, gender and heart rate in the RG CCTA arm. Scans were performed using a 64-slice multidetector CT scanner. All 15 coronary segments were evaluated subjectively for image quality using a 5-point visual scale. Dose-length product was recorded for each patient and the effective radiation dose was calculated The PG CCTA technique demonstrated a significantly higher incidence of step artifacts in the middle and distal right coronary artery, the distal left anterior descending artery, the second diagonal, the distal left circumflex artery, and the second marginal branches. Nevertheless, the diagnostic performance of these scans was not adversely affected. The mean effective radiation doses were 3.8 +/- 0.9 mSv vs.17.2 +/- 3 mSv for PG CCTA and RG CCTA, respectively (P acute chest pain "fast track" evaluation targeted at relatively young subjects in a chest pain unit.

  12. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  13. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the head uses special x-ray equipment to help assess head injuries, severe headaches, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  14. Chest computed tomography

    DEFF Research Database (Denmark)

    Loeve, Martine; Krestin, Gabriel P.; Rosenfeld, Margaret

    2013-01-01

    are not suitable to study CF lung disease in young children. Chest computed tomography (CT) holds great promise for use as a sensitive surrogate endpoint in CF. A large body of evidence has been produced to validate the use of chest CT as primary endpoint to study CF lung disease. However, before chest CT can...

  15. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside of ...

  16. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... top of page What are some common uses of the procedure? CT scanning of the head is ...

  17. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... you through a built-in intercom system. With pediatric patients, a parent may be allowed in the room ... Share your patient story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

  18. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... you through a built-in intercom system. With pediatric patients, a parent may be allowed in the room ... Share your patient story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

  19. Computed Tomography (CT) -- Sinuses

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses ...

  20. Computed Tomography (CT) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head ...

  1. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is ... a CT scan. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

  2. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... clinical problems. CT is less sensitive to patient movement than MRI. CT can be performed if you ... Images related to Children's (Pediatric) CT (Computed Tomography) Videos related to Children's (Pediatric) CT (Computed Tomography) Sponsored ...

  3. SU-E-I-107: Suitability of Various Radiation Detectors Used in Radiation Therapy for X-Ray Dosimetry in Computed Tomography.

    Science.gov (United States)

    Liebmann, M; Poppe, B; von Boetticher, H

    2012-06-01

    Assessment of suitability for X-ray dosimetry in computed tomography of various ionization chambers, diodes and two-dimensional detector arrays primarily used in radiation therapy. An Oldelft X-ray simulation unit was used to irradiate PTW 60008, 60012 dosimetry diodes, PTW 23332, 31013, 31010, 31006 axial symmetrical ionization chambers, PTW 23343, 34001 plane parallel ionization chambers and PTW Starcheck and 2D-Array seven29 as well as a prototype Farmer chamber with a copper wall. Peak potential was varied from 50 kV up to 125 kV and beam qualities were quantified through half-value-layer measurements. Energy response was investigated free in air as well as in 2 cm depth in a solid water phantom and refers to a manufacturer calibrated PTW 60004 diode for kV-dosimetry. The thimble ionization chambers PTW 31010, 31013, the uncapsuled diode PTW 60012 and the PTW 2D-Array seven29 exhibit an energy response deviation in the investigated energy region of approximately 10% or lower thus proving good usability in X-ray dosimetry if higher spatial resolution is needed or rotational irradiations occur. It could be shown that in radiation therapy routinely used detectors are usable in a much lower energy region. The rotational symmetry is of advantage in computed tomography dosimetry and enables dose profile as well as point dose measurements in a suitable phantom for estimation of organ doses. Additional the PTW 2D-Array seven29 can give a quick overview of radiation fields in non-rotating tasks. © 2012 American Association of Physicists in Medicine.

  4. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses ... limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  5. Cone-beam computed tomography (CBCT) for adaptive image guided head and neck radiation therapy

    DEFF Research Database (Denmark)

    Hvid, Christian A; Elstrøm, Ulrik V; Jensen, Kenneth

    2017-01-01

    tomography (CT) and CBCT-based dose verification respectively. In the CBCT cohort, patients at high risk of xerostomia received weekly dose surveillance, while low-risk patients received a mid-course CBCT review. For weekly surveillance, predicted total doses to parotid glands, spinal cord and brainstem were...

  6. Low-dose radiation with 80-kVp computed tomography to diagnose pulmonary embolism: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Nyman, Ulf [Dept. of Radiology, Univ. of Lund, Lasarettet Trelleborg, Trelleborg (Sweden)], E-mail: ulf.nyman@skane.se; Bjoerkdahl, Peter [Dept. of Radiology, Lasarettet Trelleborg, Trelleborg (Sweden); Olsson, Marie-Louise; Gunnarsson, Mikael [Medical Radiation Physics, Dept. of Clinical Sciences, Univ. of Lund, Skaane Univ. Hospital, Malmoe (Sweden); Goldman, Bitte [Dept. of Internal Medicine, Lasarettet Trelleborg, Trelleborg (Sweden)

    2012-11-15

    Background Mounting collective radiation doses from computed tomography (CT) implies an increased risk of radiation-induced cancer in exposed populations, especially in the young. Purpose To evaluate radiation dose and image quality at 80-kVp CT to diagnose acute pulmonary embolism (PE) compared with a previous study at 100 and 120 kVp with all other scanning parameters unchanged. Material and Methods A custom-made chest phantom with a 12 mg I/mL-syringe was scanned at 80/100/120 kVp to evaluate relative changes in computed tomographic dose index (CTDIvol), attenuation, image noise, and contrast-to-noise ratio (CNR). Fifty patients underwent 80 kVp 16-row detector CT at 100 'Quality reference' mAs. A total of 350 mg I/kg were injected to compensate for increased CNR at 80 kVp, while 300 mg I/kg had been used at 100/120 kVp. CTDI{sub vol}, dose-length product (DLP), and estimated effective dose were evaluated including Monte Carlo simulations. Pulmonary artery attenuation and noise were measured and CNR calculated. Two radiologists evaluated subjective image quality using a four-grade scale. Results Switching from 120 to 80 kVp in the phantom study decreased radiation dose by 67% while attenuation and noise increased 1.6 and 2.0 times, respectively, and CNR decreased by 16%. Switching from 120 to 80 kVp in the patient studies decreased estimated effective dose from 4.0 to 1.2 mSv (70% decrease) in median while pulmonary artery attenuation and noise roughly doubled from 332 to 653 HU and from 22 to 49 HU, respectively, resulting in similar CNR (13 vs. 12). At 80 kVp all examinations were regarded as adequate (8%) or excellent (92%). Conclusion Switching from 120 to 80 kVp CT without increased mAs but slightly increased iodine dose may be of special benefit to diagnose PE in younger individuals with preserved renal function where the primary aim is to minimize radiation dose and reaching levels below that of scintigraphy.

  7. Computed tomography status

    Energy Technology Data Exchange (ETDEWEB)

    Hansche, B.D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  8. Mathematics of Computed Tomography

    Science.gov (United States)

    Hawkins, William Grant

    A review of the applications of the Radon transform is presented, with emphasis on emission computed tomography and transmission computed tomography. The theory of the 2D and 3D Radon transforms, and the effects of attenuation for emission computed tomography are presented. The algebraic iterative methods, their importance and limitations are reviewed. Analytic solutions of the 2D problem the convolution and frequency filtering methods based on linear shift invariant theory, and the solution of the circular harmonic decomposition by integral transform theory--are reviewed. The relation between the invisible kernels, the inverse circular harmonic transform, and the consistency conditions are demonstrated. The discussion and review are extended to the 3D problem-convolution, frequency filtering, spherical harmonic transform solutions, and consistency conditions. The Cormack algorithm based on reconstruction with Zernike polynomials is reviewed. An analogous algorithm and set of reconstruction polynomials is developed for the spherical harmonic transform. The relations between the consistency conditions, boundary conditions and orthogonal basis functions for the 2D projection harmonics are delineated and extended to the 3D case. The equivalence of the inverse circular harmonic transform, the inverse Radon transform, and the inverse Cormack transform is presented. The use of the number of nodes of a projection harmonic as a filter is discussed. Numerical methods for the efficient implementation of angular harmonic algorithms based on orthogonal functions and stable recursion are presented. The derivation of a lower bound for the signal-to-noise ratio of the Cormack algorithm is derived.

  9. Radiation dose measurements during kilovoltage-cone beam computed tomography imaging in radiotherapy

    Directory of Open Access Journals (Sweden)

    A Sathish Kumar

    2016-01-01

    Conclusion: Radiation dose to the eye, breast, and the surface of the pelvis have been arrived at during CBCT. The doses measured on patients agreed closely with those measured on humanoid phantom and with published values.

  10. High-Resolution Computed Tomography Examinations for Chronic Suppurative Lung Disease in Early Childhood: Radiation Exposure and Image Quality Evaluations With Iterative Reconstruction Algorithm Use.

    Science.gov (United States)

    Smarda, Magdalini; Efstathopoulos, Efstathios; Mazioti, Argyro; Kordolaimi, Sofia; Ploussi, Agapi; Priftis, Konstantinos; Kelekis, Nikolaos; Alexopoulou, Efthymia

    2016-08-01

    High radiosensitivity of children undergoing repetitive computed tomography examinations necessitates the use of iterative reconstruction algorithms in order to achieve a significant radiation dose reduction. The goal of this study is to compare the iDose iterative reconstruction algorithm with filtered backprojection in terms of radiation exposure and image quality in 33 chest high-resolution computed tomography examinations performed in young children with chronic bronchitis. Fourteen patients were scanned using the filtered backprojection protocol while 19 patients using the iDose protocol and reduced milliampere-seconds, both on a 64-detector row computed tomography scanner. The iDose group images were reconstructed with different iDose levels (2, 4, and 6). Radiation exposure quantities were estimated, while subjective and objective image qualities were evaluated. Unpaired t tests were used for data statistical analysis. The iDose application allowed significant effective dose reduction (about 80%). Subjective image quality evaluation showed satisfactory results even with iDose level 2, whereas it approached excellent image with iDose level 6. Subjective image noise was comparable between the 2 groups with the use of iDose level 4, while objective noise was comparable between filtered backprojection and iterative reconstruction level 6 images. The iDose algorithm use in pediatric chest high-resolution computed tomography reduces radiation exposure without compromising image quality. Further evaluation with iterative reconstruction algorithms is needed in order to establish high-resolution computed tomography as the gold standard low-dose method for children suffering from chronic lung diseases. Copyright © 2016 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  11. Improving Radiation Awareness and Feeling of Personal Security of Non-Radiological Medical Staff by Implementing a Traffic Light System in Computed Tomography.

    Science.gov (United States)

    Heilmaier, C; Mayor, A; Zuber, N; Fodor, P; Weishaupt, D

    2016-03-01

    Non-radiological medical professionals often need to remain in the scanning room during computed tomography (CT) examinations to supervise patients in critical condition. Independent of protective devices, their position significantly influences the radiation dose they receive. The purpose of this study was to assess if a traffic light system indicating areas of different radiation exposure improves non-radiological medical staff's radiation awareness and feeling of personal security. Phantom measurements were performed to define areas of different dose rates and colored stickers were applied on the floor according to a traffic light system: green = lowest, orange = intermediate, and red = highest possible radiation exposure. Non-radiological medical professionals with different years of working experience evaluated the system using a structured questionnaire. Kruskal-Wallis and Spearman's correlation test were applied for statistical analysis. Fifty-six subjects (30 physicians, 26 nursing staff) took part in this prospective study. Overall rating of the system was very good, and almost all professionals tried to stand in the green stickers during the scan. The system significantly increased radiation awareness and feeling of personal protection particularly in staff with ≤ 5 years of working experience (p radiation protection was poor in all groups, especially among entry-level employees (p radiation exposure is much appreciated. It increases radiation awareness, improves the sense of personal radiation protection, and may support endeavors to lower occupational radiation exposure, although the best radiation protection always is to re-main outside the CT room during the scan. • A traffic light system indicating areas with different radiation exposure within the computed tomography scanner room is much appreciated by non-radiological medical staff. • The traffic light system increases non-radiological medical staff's radiation awareness and feeling of

  12. Multislice computed tomography coronary angiography

    NARCIS (Netherlands)

    F. Cademartiri (Filippo)

    2005-01-01

    markdownabstract__Abstract__ Computed Tomography (CT) imaging is also known as "CAT scanning" (Computed Axial Tomography). Tomography is from the Greek word "tomos" meaning "slice" or "section" and "graphia" meaning "describing". CT was invented in 1972 by British engineer Godfrey Hounsfield

  13. Fatigue Micromechanism Characterization in Carbon Fibre Reinforced Polymers Using Synchrotron Radiation Computed Tomography

    Science.gov (United States)

    2014-12-18

    tests was very similar, at 1.4 µm. Scans were conducted at the Swiss Light Source (SLS), TOMCAT-X02DA Beamline , Paul Scherrer Institut...Also funding from EPSRC, grant EP/H1506X/1. The authors are grateful to the Swiss Light Synchrotron Radiation for access to TOMCAT-X02DA beamline

  14. Characterization of a human tooth with carious lesions using conventional and synchrotron radiation-based micro computed tomography

    Science.gov (United States)

    Dziadowiec, Iwona; Beckmann, Felix; Schulz, Georg; Deyhle, Hans; Müller, Bert

    2014-09-01

    In a dental office, every day X rays of teeth within the oral cavity are obtained. Caries induces a mineral loss and, therefore, becomes visible by reduced X-ray absorption. The detailed spatial distribution of the mineral loss, however, is inaccessible in conventional dental radiology, since the dose for such studies is intolerable. As a consequence, such measurements can only be performed after tooth extraction. We have taken advantage of synchrotron radiation-based micro computed tomography to characterize a human tooth with a rather small, natural caries lesion and an artificially induced lesion provoked by acidic etching. Both halves of the tooth were separately visualized from 2400 radiographs recorded at the beam line P07 / PETRA III (HASYLAB at DESY, Hamburg, Germany) with an asymmetric rotation axis at photon energy of 45 keV. Because of the setup, one finds an energy shift in the horizontal plane, to be corrected. After the appropriate three-dimensional registration of the data with the ones of the same crown using the better accessible phoenix nanotom® m of General Electric, Wunstorf, Germany, one can determine the joint histogram, which enable to calibrate the system with the conventional X-ray source.

  15. Multiplanner spine computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. K.; Jeon, H. J.; Hong, K. C.; Chung, K. B.; Suh, W. H. [Korea University College of Medicine, Seoul (Korea, Republic of)

    1983-06-15

    The computed tomography is useful in evaluation of bony structures and adjacent soft tissues of the spine. Recently, the multiplanar spine CT scan is highly superior than usual axial scan, because of easily demonstrable longitudinal dimension, level of spine and spinal canal. We evaluated 62 cases of spine CT, whom complains of spinal symptoms, from July, 1982 to January, 1983. The results were as follows: 1. The sex distribution of cases were 45 male and 17 female, ages were from 15 years to 76 years, and sites were 15 cervical spine, 7 thoracic spine, 42 lumbar spine and 21 sacral spine. 2. Sixty two cases of the CT diagnosis were reviewed and shows 19 cases of herniated intervertebral disc, 7 cases of spine fracture, 5 cases of degenerative disease, 4 cases of metastatic cancer, 2 cases of posterior longitudinal ligament ossification, 1 case of cord injury and 24 cases of normal. 3. The CT findings of herniated intervertebral disc were protruding disc, obliteration of anterior epidural fat, with or without indentation of dural sac and calcification within posterior disc margin. In cases of trauma, the multiplanar spine CT scan detects more specific extension of the fracture sites, and it is able to demonstrate relationship between fracture fragment and spinal cord, therefore operability can be decided. In case of posterior longitudinal ligament ossification, it is easy to demonstrate linear high density along posterior margin of vertebral bodies on sagittal reconstruction scan. 4. The computed tomography is diagnostic in detection of spinal disease. However, multiplanar spine CT is more diagnostic than axial computed tomography such as detecting the longitudinal dimension and demonstration of spinal canal.

  16. Radiation protection issues in dynamic contrast-enhanced (perfusion) computed tomography.

    Science.gov (United States)

    Brix, Gunnar; Lechel, Ursula; Nekolla, Elke; Griebel, Jürgen; Becker, Christoph

    2015-12-01

    Dynamic contrast-enhanced (DCE) CT studies are increasingly used in both medical care and clinical trials to improve diagnosis and therapy management of the most common life-threatening diseases: stroke, coronary artery disease and cancer. It is thus the aim of this review to briefly summarize the current knowledge on deterministic and stochastic radiation effects relevant for patient protection, to present the essential concepts for determining radiation doses and risks associated with DCE-CT studies as well as representative results, and to discuss relevant aspects to be considered in the process of justification and optimization of these studies. For three default DCE-CT protocols implemented at a latest-generation CT system for cerebral, myocardial and cancer perfusion imaging, absorbed doses were measured by thermoluminescent dosimeters at an anthropomorphic body phantom and compared with thresholds for harmful (deterministic) tissue reactions. To characterize stochastic radiation risks of patients from these studies, life-time attributable cancer risks (LAR) were estimated using sex-, age-, and organ-specific risk models based on the hypothesis of a linear non-threshold dose-response relationship. For the brain, heart and pelvic cancer studies considered, local absorbed doses in the imaging field were about 100-190 mGy (total CTDI(vol), 200 mGy), 15-30 mGy (16 mGy) and 80-270 mGy (140 mGy), respectively. According to a recent publication of the International Commission on Radiological Protection (ICRP Publication 118, 2012), harmful tissue reactions of the cerebro- and cardiovascular systems as well as of the lenses of the eye become increasingly important at radiation doses of more than 0.5 Gy. The LARs estimated for the investigated cerebral and myocardial DCE-CT scenarios are less than 0.07% for males and 0.1% for females at an age of exposure of 40 years. For the considered tumor location and protocol, the corresponding LARs are more than 6 times as high

  17. Automated segmentation of synchrotron radiation micro-computed tomography biomedical images using Graph Cuts and neural networks

    Science.gov (United States)

    Alvarenga de Moura Meneses, Anderson; Giusti, Alessandro; de Almeida, André Pereira; Parreira Nogueira, Liebert; Braz, Delson; Cely Barroso, Regina; deAlmeida, Carlos Eduardo

    2011-12-01

    Synchrotron Radiation (SR) X-ray micro-Computed Tomography (μCT) enables magnified images to be used as a non-invasive and non-destructive technique with a high space resolution for the qualitative and quantitative analyses of biomedical samples. The research on applications of segmentation algorithms to SR-μCT is an open problem, due to the interesting and well-known characteristics of SR images for visualization, such as the high resolution and the phase contrast effect. In this article, we describe and assess the application of the Energy Minimization via Graph Cuts (EMvGC) algorithm for the segmentation of SR-μCT biomedical images acquired at the Synchrotron Radiation for MEdical Physics (SYRMEP) beam line at the Elettra Laboratory (Trieste, Italy). We also propose a method using EMvGC with Artificial Neural Networks (EMANNs) for correcting misclassifications due to intensity variation of phase contrast, which are important effects and sometimes indispensable in certain biomedical applications, although they impair the segmentation provided by conventional techniques. Results demonstrate considerable success in the segmentation of SR-μCT biomedical images, with average Dice Similarity Coefficient 99.88% for bony tissue in Wistar Rats rib samples (EMvGC), as well as 98.95% and 98.02% for scans of Rhodnius prolixus insect samples (Chagas's disease vector) with EMANNs, in relation to manual segmentation. The techniques EMvGC and EMANNs cope with the task of performing segmentation in images with the intensity variation due to phase contrast effects, presenting a superior performance in comparison to conventional segmentation techniques based on thresholding and linear/nonlinear image filtering, which is also discussed in the present article.

  18. Automated segmentation of synchrotron radiation micro-computed tomography biomedical images using Graph Cuts and neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Alvarenga de Moura Meneses, Anderson, E-mail: ameneses@ieee.org [Radiological Sciences Laboratory, Rio de Janeiro State University, Rua Sao Francisco Xavier 524, CEP 20550-900, RJ (Brazil); Giusti, Alessandro [IDSIA (Dalle Molle Institute for Artificial Intelligence), University of Lugano (Switzerland); Pereira de Almeida, Andre; Parreira Nogueira, Liebert; Braz, Delson [Nuclear Engineering Program, Federal University of Rio de Janeiro, RJ (Brazil); Cely Barroso, Regina [Laboratory of Applied Physics on Biomedical Sciences, Physics Department, Rio de Janeiro State University, RJ (Brazil); Almeida, Carlos Eduardo de [Radiological Sciences Laboratory, Rio de Janeiro State University, Rua Sao Francisco Xavier 524, CEP 20550-900, RJ (Brazil)

    2011-12-21

    Synchrotron Radiation (SR) X-ray micro-Computed Tomography ({mu}CT) enables magnified images to be used as a non-invasive and non-destructive technique with a high space resolution for the qualitative and quantitative analyses of biomedical samples. The research on applications of segmentation algorithms to SR-{mu}CT is an open problem, due to the interesting and well-known characteristics of SR images for visualization, such as the high resolution and the phase contrast effect. In this article, we describe and assess the application of the Energy Minimization via Graph Cuts (EMvGC) algorithm for the segmentation of SR-{mu}CT biomedical images acquired at the Synchrotron Radiation for MEdical Physics (SYRMEP) beam line at the Elettra Laboratory (Trieste, Italy). We also propose a method using EMvGC with Artificial Neural Networks (EMANNs) for correcting misclassifications due to intensity variation of phase contrast, which are important effects and sometimes indispensable in certain biomedical applications, although they impair the segmentation provided by conventional techniques. Results demonstrate considerable success in the segmentation of SR-{mu}CT biomedical images, with average Dice Similarity Coefficient 99.88% for bony tissue in Wistar Rats rib samples (EMvGC), as well as 98.95% and 98.02% for scans of Rhodnius prolixus insect samples (Chagas's disease vector) with EMANNs, in relation to manual segmentation. The techniques EMvGC and EMANNs cope with the task of performing segmentation in images with the intensity variation due to phase contrast effects, presenting a superior performance in comparison to conventional segmentation techniques based on thresholding and linear/nonlinear image filtering, which is also discussed in the present article.

  19. Early Assessment of Treatment Responses During Radiation Therapy for Lung Cancer Using Quantitative Analysis of Daily Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Jijo; Yang, Cungeng [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Wu, Hui [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou (China); Tai, An [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Dalah, Entesar [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Department of Medical Diagnostic Imaging, College of Health Science, University of Sharjah (United Arab Emirates); Zheng, Cheng [Biostatistics, Joseph. J. Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin (United States); Johnstone, Candice [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Kong, Feng-Ming [Department of Radiation Oncology, Indiana University, Indianapolis, Indiana (United States); Gore, Elizabeth [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Li, X. Allen, E-mail: ali@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)

    2017-06-01

    Purpose: To investigate early tumor and normal tissue responses during the course of radiation therapy (RT) for lung cancer using quantitative analysis of daily computed tomography (CT) scans. Methods and Materials: Daily diagnostic-quality CT scans acquired using CT-on-rails during CT-guided RT for 20 lung cancer patients were quantitatively analyzed. On each daily CT set, the contours of the gross tumor volume (GTV) and lungs were generated and the radiation dose delivered was reconstructed. The changes in CT image intensity (Hounsfield unit [HU]) features in the GTV and the multiple normal lung tissue shells around the GTV were extracted from the daily CT scans. The associations between the changes in the mean HUs, GTV, accumulated dose during RT delivery, and patient survival rate were analyzed. Results: During the RT course, radiation can induce substantial changes in the HU histogram features on the daily CT scans, with reductions in the GTV mean HUs (dH) observed in the range of 11 to 48 HU (median 30). The dH is statistically related to the accumulated GTV dose (R{sup 2} > 0.99) and correlates weakly with the change in GTV (R{sup 2} = 0.3481). Statistically significant increases in patient survival rates (P=.038) were observed for patients with a higher dH in the GTV. In the normal lung, the 4 regions proximal to the GTV showed statistically significant (P<.001) HU reductions from the first to last fraction. Conclusion: Quantitative analysis of the daily CT scans indicated that the mean HUs in lung tumor and surrounding normal tissue were reduced during RT delivery. This reduction was observed in the early phase of the treatment, is patient specific, and correlated with the delivered dose. A larger HU reduction in the GTV correlated significantly with greater patient survival. The changes in daily CT features, such as the mean HU, can be used for early assessment of the radiation response during RT delivery for lung cancer.

  20. Collimation and Image Quality of C-Arm Computed Tomography: Potential of Radiation Dose Reduction While Maintaining Equal Image Quality.

    Science.gov (United States)

    Werncke, Thomas; von Falck, Christian; Luepke, Matthias; Stamm, Georg; Wacker, Frank K; Meyer, Bernhard Christian

    2015-08-01

    The aim of this study was to assess the potential for radiation dose reduction in collimated C-arm computed tomography (CACT) while maintaining the image quality of the full field of view (FFOV) acquisition. A whole-body anthropomorphic phantom representing a 70-kg male was used in this study. The upper abdomen of the phantom was imaged using an angiographic system (Artis Zeego Q; Siemens Healthcare, Germany) with either the standard detector radiation dose level (RDL; D100, 360 nGy) or 14 experimental reduced RDLs ranging from 95% (D95, 342 nGy) to 30% D100 (D30, 108 nGy). Either the FFOV (craniocaudal coverage, 18 cm) or a collimated field of view (CFOV; craniocaudal coverage, 6 cm) was applied. The organ dose was measured using thermoluminescence detector dosimetry, and the mean effective dose was computed according to the recommendations by the International Commission on Radiological Protection Publication 103. To compare the CFOV and the FFOV data sets, image quality was assessed in terms of high- and low-contrast resolution by calculating the modulation transfer function using the wire method as well as the image noise, signal-to-noise ratio, and contrast-to-noise ratio using a low-contrast insert placed in the upper abdomen (Δ50 HU). Collimated imaging (CFOV) covering 33% of the FFOV led to an increase in the x-ray tube output of 152% for CFOV (D100; FFOV, 95.5 mGy; CFOV, 147.7 mGy) to maintain the detector dose. The mean effective dose of D100 was 6.0 mSv (male) and 6.2 mSv (female) for the FFOV and 3.7 mSv (male) and 4.1 mSv (female) for the CFOV. High-contrast resolution was comparable for all acquisition protocols (mean 10% modulation transfer function ± 95% confidence interval; FFOV, 8.8 ± 0.1 line pairs/cm; CFOV, 8.8 ± 0.1 line pairs/cm). Low-contrast resolution was superior for the CFOV compared with that for the FFOV for each RDL (D100; image noise: FFOV, 34 ± 2 HU; CFOV, 22 ± 1 HU; contrast-to-noise ratio: FFOV, 1.3 ± 0.2; CFOV, 1.8 ± 0

  1. Radiation Dose to the Lens of the Eye from Computed Tomography Scans of the Head

    Science.gov (United States)

    Januzis, Natalie Ann

    While it is well known that exposure to radiation can result in cataract formation, questions still remain about the presence of a dose threshold in radiation cataractogenesis. Since the exposure history from diagnostic CT exams is well documented in a patient's medical record, the population of patients chronically exposed to radiation from head CT exams may be an interesting area to explore for further research in this area. However, there are some challenges in estimating lens dose from head CT exams. An accurate lens dosimetry model would have to account for differences in imaging protocols, differences in head size, and the use of any dose reduction methods. The overall objective of this dissertation was to develop a comprehensive method to estimate radiation dose to the lens of the eye for patients receiving CT scans of the head. This research is comprised of a physics component, in which a lens dosimetry model was derived for head CT, and a clinical component, which involved the application of that dosimetry model to patient data. The physics component includes experiments related to the physical measurement of the radiation dose to the lens by various types of dosimeters placed within anthropomorphic phantoms. These dosimeters include high-sensitivity MOSFETs, TLDs, and radiochromic film. The six anthropomorphic phantoms used in these experiments range in age from newborn to adult. First, the lens dose from five clinically relevant head CT protocols was measured in the anthropomorphic phantoms with MOSFET dosimeters on two state-of-the-art CT scanners. The volume CT dose index (CTDIvol), which is a standard CT output index, was compared to the measured lens doses. Phantom age-specific CTDIvol-to-lens dose conversion factors were derived using linear regression analysis. Since head size can vary among individuals of the same age, a method was derived to estimate the CTDIvol-to-lens dose conversion factor using the effective head diameter. These conversion

  2. Reduced radiation exposure for face transplant surgical planning computed tomography angiography.

    Directory of Open Access Journals (Sweden)

    Kurt Schultz

    Full Text Available OBJECTIVE: To test the hypothesis that wide area detector face transplant surgical planning CT angiograms with simulated lower radiation dose and iterative reconstruction (AIDR3D are comparable in image quality to those with standard tube current and filtered back projection (FBP reconstruction. MATERIALS AND METHODS: The sinograms from 320-detector row CT angiography of four clinical candidates for face transplantation were processed utilizing standard FBP, FBP with simulated 75, 62, and 50% tube current, and AIDR3D with corresponding dose reduction. Signal-to-noise ratio (SNR and contrast-to-noise ratio (CNR were measured at muscle, fat, artery, and vein. Image quality for each reconstruction strategy was assessed by two independent readers using a 4-point scale. RESULTS: Compared to FBP, the median SNR and CNR for AIDR3D images were higher at all sites for all 4 different tube currents. The AIDR3D with simulated 50% tube current achieved comparable SNR and CNR to FBP with standard dose (median muscle SNR: 5.77 vs. 6.23; fat SNR: 6.40 vs. 5.75; artery SNR: 43.8 vs. 45.0; vein SNR: 54.9 vs. 55.7; artery CNR: 38.1 vs. 38.6; vein CNR: 49.0 vs. 48.7; all p-values >0.19. The interobserver agreement in the image quality score was good (weighted κ = 0.7. The overall score and the scores for smaller arteries were significantly lower when FBP with 50% dose reduction was used. The AIDR3D reconstruction images with 4 different simulated doses achieved a mean score ranging from 3.68 to 3.82 that were comparable to the scores from images reconstructed using FBP with original dose (3.68-3.77. CONCLUSIONS: Simulated radiation dose reduction applied to clinical CT angiography for face transplant planning suggests that AIDR3D allows for a 50% reduction in radiation dose, as compared to FBP, while preserving image quality.

  3. [Computed tomography of pneumoconiosis].

    Science.gov (United States)

    Zhang, X; Kusaka, Y; Ishii, Y

    1995-09-01

    This review describes the usefulness of computed tomography (CT) and high-resolution computed tomography (HRCT) in image evaluation in pneumoconiosis. For pneumoconiosis, in the same way as for other diffuse lung diseases, conventional CT includes 10 mm collimation scans at 1 cm intervals from the apex to the base of the lung, whereas HRCT uses five to six 1.2 to 3 mm collimation scans at predetermined representative locations including the aortic arch, the tracheal carina, and 2 cm above the dome of the right hemidiaphragm. The CT scans are performed in the supine position in silicosis and coal workers' pneumoconiosis, and both in the supine and prone position in asbestosis. In silicosis, CT is superior to chest radiography in detecting coalescence of nodules and early stage formation of large opacities. There are good correlations between HRCT findings and histological changes, especially in secondary pulmonary lobules. With HRCT, small nodules are found to be located in the center of the secondary pulmonary lobule in silicotic lungs. The mild emphysematous change associated with silicosis can also be found with HRCT. In coal workers' pneumoconiosis, the HRCT is useful in detecting nodules located in the subpleural and fissural subpleural areas. In asbestosis, the conventional CT can detect pleural plaques more sensitively than chest radiography. HRCT is also especially useful in detecting earlier fibrotic change in asbestosis in lung parenchyma, apparent as subpleural lines, parenchymal bands, subpleural curvilinear line shadows and so on.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Longitudinal assessment of carotid atherosclerosis after Radiation Therapy using Computed Tomography: A case control Study

    Energy Technology Data Exchange (ETDEWEB)

    Anzidei, Michele [Rome Univ. ' ' La Sapienza' ' (Italy). Dept. of Radiology; Suri, Jasjit S.; Piga, Mario [AtheroPoint TM LLC, Roseville, CA (United States). Monitoring and Diagnostic Div.; Global Biomedical Technologies, Inc., CA (United States). Point of Care Devices; Idaho Univ., Moscow, ID (United States). Electrical Engineering Dept.; Saba, Luca [Azienda Ospedaliero Universitaria (A.O.U.), Cagliari (Italy). Dept. of Radiology; Sanfilippo, Roberto; Montisci, Roberto [Azienda Ospedaliero Universitaria (A.O.U.), Cagliari (Italy). Dept. of Vascular Surgery; Laddeo, Giancarlo [New York Univ. Langone Medical Center, New York, NY (United States). Dept. of Radiology; Argiolas, Giovanni Maria [Azienda Ospedaliera Brotzu, Cagliari (Italy). Dept. of Radiology; Raz, Eytan [Rome Univ. ' ' La Sapienza' ' (Italy). Dept. of Radiology; New York Univ. Langone Medical Center, New York, NY (United States). Dept. of Radiology

    2016-01-15

    To study the carotid artery plaque composition and its volume changes in a group of patients at baseline and 2 years after head and neck radiation therapy treatment (HNXRT). In this retrospective study, 62 patients (41 males; mean age 63 years; range 52-81) who underwent HNXRT and 40 patients (24 males; mean age 65) who underwent surgical resection of neoplasm and did not undergo HNXRT were assessed, with 2-year follow-up. The carotid artery plaque volumes, as well as the volume of the sub-components (fatty-mixed-calcified), were semiautomatically quantified. Mann-Whitney and Wilcoxon tests were used to test the hypothesis. In the HNXRT group, there was a statistically significant increase in the total volume of the carotid artery plaques (from 533 to 746 mm{sup 3}; p = 0.001), in the fatty plaques (103 vs. 202 mm{sup 3}; p = 0.001) and mixed plaque component volume (328 vs. 419 mm{sup 3}; p = 0.034). A statistically significant variation (from 21.8 % to 27.6 %) in the percentage of the fatty tissue was found. of this preliminary study suggest that HNXRT promotes increased carotid artery plaque volume, particularly the fatty plaque component. (orig.)

  5. Cardiac-Specific Conversion Factors to Estimate Radiation Effective Dose From Dose-Length Product in Computed Tomography.

    Science.gov (United States)

    Trattner, Sigal; Halliburton, Sandra; Thompson, Carla M; Xu, Yanping; Chelliah, Anjali; Jambawalikar, Sachin R; Peng, Boyu; Peters, M Robert; Jacobs, Jill E; Ghesani, Munir; Jang, James J; Al-Khalidi, Hussein; Einstein, Andrew J

    2017-08-16

    This study sought to determine updated conversion factors (k-factors) that would enable accurate estimation of radiation effective dose (ED) for coronary computed tomography angiography (CTA) and calcium scoring performed on 12 contemporary scanner models and current clinical cardiac protocols and to compare these methods to the standard chest k-factor of 0.014 mSv·mGy(-1)cm(-1). Accurate estimation of ED from cardiac CT scans is essential to meaningfully compare the benefits and risks of different cardiac imaging strategies and optimize test and protocol selection. Presently, ED from cardiac CT is generally estimated by multiplying a scanner-reported parameter, the dose-length product, by a k-factor which was determined for noncardiac chest CT, using single-slice scanners and a superseded definition of ED. Metal-oxide-semiconductor field-effect transistor radiation detectors were positioned in organs of anthropomorphic phantoms, which were scanned using all cardiac protocols, 120 clinical protocols in total, on 12 CT scanners representing the spectrum of scanners from 5 manufacturers (GE, Hitachi, Philips, Siemens, Toshiba). Organ doses were determined for each protocol, and ED was calculated as defined in International Commission on Radiological Protection Publication 103. Effective doses and scanner-reported dose-length products were used to determine k-factors for each scanner model and protocol. k-Factors averaged 0.026 mSv·mGy(-1)cm(-1) (95% confidence interval: 0.0258 to 0.0266) and ranged between 0.020 and 0.035 mSv·mGy(-1)cm(-1). The standard chest k-factor underestimates ED by an average of 46%, ranging from 30% to 60%, depending on scanner, mode, and tube potential. Factors were higher for prospective axial versus retrospective helical scan modes, calcium scoring versus coronary CTA, and higher (100 to 120 kV) versus lower (80 kV) tube potential and varied among scanner models (range of average k-factors: 0.0229 to 0.0277 mSv·mGy(-1)cm(-1)). Cardiac

  6. Estimation of radiation exposure in low-dose multislice computed tomography of the heart and comparison with a calculation program

    Energy Technology Data Exchange (ETDEWEB)

    Hohl, C.; Muehlenbruch, G.; Wildberger, J.E.; Schmidt, T.; Guenther, R.W.; Mahnken, A.H. [University of Technology of Aachen, Department of Diagnostic Radiology, Aachen (Germany); Leidecker, C. [University of Erlangen-Nuremberg, Institute of Medical Physics, Erlangen (Germany); Suess, C. [Siemens Medical Solutions Computed Tomography, Forchheim (Germany)

    2006-08-15

    The purpose of this study was to evaluate the achievable organ dose savings in low-dose multislice computed tomography (MSCT) of the heart using different tube voltages (80 kVp, 100 kVp, 120 kVp) and compare it with calculated values. A female Alderson-Rando phantom was equipped with thermoluminescent dosimeters (TLDs) in five different positions to assess the mean doses within representative organs (thyroid gland, thymus, oesophagus, pancreas, liver). Radiation exposure was performed on a 16-row MSCT scanner with six different routine scan protocols: a 120-kV and a 100-kV CT angiography (CTA) protocol with the same collimation, two 120-kV Ca-scoring (CS) protocols with different collimations and two 80-kV CS protocols with the same collimation as the 120-kV CS protocols. Each scan protocol was repeated five times. The measured dose values for the organs were compared with the values calculated by a commercially available computer program. Directly irradiated organs, such as the esophagus, received doses of 34.7 mSv (CTA 16 x 0.75 120 kVp), 21.9 mSv (CTA 16 x 0.75 100 kVp) and 4.96 mSv (CS score 12 x 1.5 80 kVp), the thyroid as an organ receiving only scattered radiation collected organ doses of 2.98 mSv (CTA 16 x 0.75 120 kVp), 1.97 mSv (CTA 16 x 0.75 100 kVp) and 0.58 mSv (CS score 12 x 1.5 80 kVp). The measured relative organ dose reductions from standard to low-kV protocols ranged from 30.9% to 55.9% and were statistically significant (P<0.05). The comparison with the calculated organ doses showed that the calculation program can predict the relative dose reduction of cardiac low photon-energy protocols precisely. (orig.)

  7. Reduction of radiation exposure and improvement of image quality with BMI-adapted prospective cardiac computed tomography and iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Hosch, Waldemar, E-mail: waldemar.hosch@med.uni-heidelberg.de [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Stiller, Wolfram [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Mueller, Dirk [Philips GmbH Healthcare Division, Hamburg (Germany); Gitsioudis, Gitsios [University of Heidelberg, Department of Cardiology, Heidelberg (Germany); Welzel, Johanna; Dadrich, Monika [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Buss, Sebastian J.; Giannitsis, Evangelos [University of Heidelberg, Department of Cardiology, Heidelberg (Germany); Kauczor, Hans U. [University of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Katus, Hugo A. [University of Heidelberg, Department of Cardiology, Heidelberg (Germany); Korosoglou, Grigorios, E-mail: gkorosoglou@hotmail.com [University of Heidelberg, Department of Cardiology, Heidelberg (Germany)

    2012-11-15

    Purpose: To assess the impact of body mass index (BMI)-adapted protocols and iterative reconstruction algorithms (iDose) on patient radiation exposure and image quality in patients undergoing prospective ECG-triggered 256-slice coronary computed tomography angiography (CCTA). Methods: Image quality and radiation exposure were systematically analyzed in 100 patients. 60 Patients underwent prospective ECG-triggered CCTA using a non-tailored protocol and served as a 'control' group (Group 1: 120 kV, 200 mA s). 40 Consecutive patients with suspected coronary artery disease (CAD) underwent prospective CCTA, using BMI-adapted tube voltage and standard (Group 2: 100/120 kV, 100-200 mA s) versus reduced tube current (Group 3: 100/120 kV, 75-150 mA s). Iterative reconstructions were provided with different iDose levels and were compared to filtered back projection (FBP) reconstructions. Image quality was assessed in consensus of 2 experienced observers and using a 5-grade scale (1 = best to 5 = worse), and signal- and contrast-to-noise ratios (SNR and CNR) were quantified. Results: CCTA was performed without adverse events in all patients (n = 100, heart rate of 47-87 bpm and BMI of 19-38 kg/m{sup 2}). Patients examined using the non-tailored protocol in Group 1 had the highest radiation exposure (3.2 {+-} 0.4 mSv), followed by Group 2 (1.7 {+-} 0.7 mSv) and Group 3 (1.2 {+-} 0.6 mSv) (radiation savings of 47% and 63%, respectively, p < 0.001). Iterative reconstructions provided increased SNR and CNR, particularly when higher iDose level 5 was applied with Multi-Frequency reconstruction (iDose5 MFR) (14.1 {+-} 4.6 versus 21.2 {+-} 7.3 for SNR and 12.0 {+-} 4.2 versus 18.1 {+-} 6.6 for CNR, for FBP versus iDose5 MFR, respectively, p < 0.001). The combination of BMI adaptation with iterative reconstruction reduced radiation exposure and simultaneously improved image quality (subjective image quality of 1.4 {+-} 0.4 versus 1.9 {+-} 0.5 for Group 2 reconstructed using

  8. Cone-beam computed tomography in lung stereotactic ablative radiation therapy: predictive parameters of early response.

    Science.gov (United States)

    Mazzola, Rosario; Fiorentino, Alba; Ricchetti, Francesco; Giaj Levra, Niccolò; Fersino, Sergio; Di Paola, Gioacchino; Lo Casto, Antonio; Ruggieri, Ruggero; Alongi, Filippo

    2016-06-20

    To analyze lung lesion volume variations by contouring on cone-beam CT (CBCT) images to evaluate the early predictive parameters of stereotactic ablative radiation therapy (SABR) treatment response. The prescribed dose of SABR was varied according to the tumour site (central or peripheral) and maximum diameter of the lesions by using a strategy of risk-adapted dose prescription with a dose range between 48 and 70 Gy in 3-10 consecutive fractions. For the purpose of the analysis, the gross tumour volume (GTV) was recontoured for each patient at first and last CBCT using two lung levels/windows: (a) -600/1000 HU and (b) -1000/250 HU. Univariate analysis was performed to evaluate a correlation between lung lesion variations on CBCT using the two levels/windows and treatment response 6 months after SABR. Independent variables were the number of fractions, time between initial and final fraction, biologically effective dose and pre-SABR GTV. Cut points of lesion volume reduction were evaluated to determine the correlation with complete response 6 months after SABR. 41 lung lesions were evaluated. 82 lung lesions were recontoured for each CBCT level/window. A lung lesion shrinkage of at least 20% was revealed to be statistically related to complete response 6 months after SABR for both the CBCT levels/windows used. The probability of complete response ranged between six and eight times higher in respect to CBCT levels/windows -600/1000 HU and -1000/250 HU, respectively, compared with patients without a lesion shrinkage of 20% at the last session of SABR. According to current findings, a lung lesion shrinkage of at least 20% at the last session of SABR could be predictable of complete response 6 months thereafter. Further investigations about this topic are needed. Prediction of the early tumour response could be useful to personalize imaging restaging after the completion of SABR or to incorporate additional therapies in case of poor responders to improve

  9. A qualitative and quantitative analysis of radiation dose and image quality of computed tomography images using adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Hussain, Fahad Ahmed; Mail, Noor; Shamy, Abdulrahman M; Suliman, Alghamdi; Saoudi, Abdelhamid

    2016-05-08

    Image quality is a key issue in radiology, particularly in a clinical setting where it is important to achieve accurate diagnoses while minimizing radiation dose. Some computed tomography (CT) manufacturers have introduced algorithms that claim significant dose reduction. In this study, we assessed CT image quality produced by two reconstruction algorithms provided with GE Healthcare's Discovery 690 Elite positron emission tomography (PET) CT scanner. Image quality was measured for images obtained at various doses with both conventional filtered back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR) algorithms. A stan-dard CT dose index (CTDI) phantom and a pencil ionization chamber were used to measure the CT dose at 120 kVp and an exposure of 260 mAs. Image quality was assessed using two phantoms. CT images of both phantoms were acquired at tube voltage (kV) of 120 with exposures ranging from 25 mAs to 400 mAs. Images were reconstructed using FBP and ASIR ranging from 10% to 100%, then analyzed for noise, low-contrast detectability, contrast-to-noise ratio (CNR), and modulation transfer function (MTF). Noise was 4.6 HU in water phantom images acquired at 260 mAs/FBP 120 kV and 130 mAs/50% ASIR 120 kV. The large objects (fre-quency ASIR, compared to 260 mAs/FBP. The application of ASIR for small objects (frequency >7 lp/cm) showed poor visibility compared to FBP at 260 mAs and even worse for images acquired at less than 130 mAs. ASIR blending more than 50% at low dose tends to reduce contrast of small objects (frequency >7 lp/cm). We concluded that dose reduction and ASIR should be applied with close attention if the objects to be detected or diagnosed are small (frequency > 7 lp/cm). Further investigations are required to correlate the small objects (frequency > 7 lp/cm) to patient anatomy and clinical diagnosis.

  10. Calibration and error analysis of metal-oxide-semiconductor field-effect transistor dosimeters for computed tomography radiation dosimetry.

    Science.gov (United States)

    Trattner, Sigal; Prinsen, Peter; Wiegert, Jens; Gerland, Elazar-Lars; Shefer, Efrat; Morton, Tom; Thompson, Carla M; Yagil, Yoad; Cheng, Bin; Jambawalikar, Sachin; Al-Senan, Rani; Amurao, Maxwell; Halliburton, Sandra S; Einstein, Andrew J

    2017-12-01

    Metal-oxide-semiconductor field-effect transistors (MOSFETs) serve as a helpful tool for organ radiation dosimetry and their use has grown in computed tomography (CT). While different approaches have been used for MOSFET calibration, those using the commonly available 100 mm pencil ionization chamber have not incorporated measurements performed throughout its length, and moreover, no previous work has rigorously evaluated the multiple sources of error involved in MOSFET calibration. In this paper, we propose a new MOSFET calibration approach to translate MOSFET voltage measurements into absorbed dose from CT, based on serial measurements performed throughout the length of a 100-mm ionization chamber, and perform an analysis of the errors of MOSFET voltage measurements and four sources of error in calibration. MOSFET calibration was performed at two sites, to determine single calibration factors for tube potentials of 80, 100, and 120 kVp, using a 100-mm-long pencil ion chamber and a cylindrical computed tomography dose index (CTDI) phantom of 32 cm diameter. The dose profile along the 100-mm ion chamber axis was sampled in 5 mm intervals by nine MOSFETs in the nine holes of the CTDI phantom. Variance of the absorbed dose was modeled as a sum of the MOSFET voltage measurement variance and the calibration factor variance, the latter being comprised of three main subcomponents: ionization chamber reading variance, MOSFET-to-MOSFET variation and a contribution related to the fact that the average calibration factor of a few MOSFETs was used as an estimate for the average value of all MOSFETs. MOSFET voltage measurement error was estimated based on sets of repeated measurements. The calibration factor overall voltage measurement error was calculated from the above analysis. Calibration factors determined were close to those reported in the literature and by the manufacturer (~3 mV/mGy), ranging from 2.87 to 3.13 mV/mGy. The error σ V of a MOSFET voltage

  11. [Quantitative structure characteristics and fractal dimension of Chinese medicine granules measured by synchrotron radiation X-ray computed micro tomography].

    Science.gov (United States)

    Lu, Xiao-long; Zheng, Qin; Yin, Xian-zhen; Xiao, Guang-qing; Liao, Zu-hua; Yang, Ming; Zhang, Ji-wen

    2015-06-01

    The shape and structure of granules are controlled by the granulation process, which is one of the main factors to determine the nature of the solid dosage forms. In this article, three kinds of granules of a traditional Chinese medicine for improving appetite and promoting digestion, namely, Jianwei Granules, were prepared using granulation technologies as pendular granulation, high speed stirring granulation, and fluidized bed granulation and the powder properties of them were investigated. Meanwhile, synchrotron radiation X-ray computed micro tomography (SR-µCT) was applied to quantitatively determine the irregular internal structures of the granules. The three-dimensional (3D) structure models were obtained by 3D reconstruction, which were more accurately to characterize the three-dimensional structures of the particles through the quantitative data. The models were also used to quantitatively compare the structural differences of granules prepared by different granulation processes with the same formula, so as to characterize how the production process plays a role in the pharmaceutical behaviors of the granules. To focus on the irregularity of the particle structure, the box counting method was used to calculate the fractal dimensions of the granules. The results showed that the fractal dimension is more sensitive to reflect the minor differences in the structure features than the conventional parameters, and capable to specifically distinct granules in structure. It is proved that the fractal dimension could quantitatively characterize the structural information of irregular granules. It is the first time suggested by our research that the fractal dimension difference (Df,c) between two fractal dimension parameters, namely, the volume matrix fractal dimension and the surface matrix fractal dimension, is a new index to characterize granules with irregular structures and evaluate the effects of production processes on the structures of granules as a new

  12. Synchrotron radiation-based micro computed tomography in the assessment of dentin de- and re-mineralization

    Science.gov (United States)

    Kernen, Florian; Waltimo, Tuomas; Deyhle, Hans; Beckmann, Felix; Stark, Wendelin; Müller, Bert

    2008-08-01

    Synchrotron radiation-based micro computed tomography (SRμCT) is well established to determine the degree of mineralization in bony tissue. The present study demonstrates that the method can be likewise used for three-dimensional analyses of dentin de- and remineralization. Four dentin discs about 4 mm in diameter and 0.8 mm thick were prepared from freshly extracted human third molars. In order to study the de- and re-mineralization, three of them were treated with 10% citric acid for the period of 10 min. Nano-particulate bioactive glass made of SiO2, P2O5, CaO, Na2O served for the re-mineralization in physiological saline. This process was carried out at the incubation temperature of 37 °C for 1 and 7 d, respectively. The native and the treated discs were comparatively examined by SRμCT in absorption contrast mode. Already the visual inspection of the tomograms obtained reveals remarkable differences related to the mean X-ray absorption and internal microstructure. The de-mineralization led to a surface morphology characteristic for the treated dentin collagen matrix. The re-mineralized discs show a dependence on the period of the treatment with the bio-active glass suspension. Initial signs of the remineralization were clearly present already after 24 h of incubation. The disc incubated for 7 d exhibits a degree of mineralization comparable to the native control disc. Thus, SRμCT is a powerful non-destructive technique for the analysis of dentin de- and re-mineralization.

  13. Impact of Computed Tomography Image Quality on Image-Guided Radiation Therapy Based on Soft Tissue Registration

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Natalya V.; Lawton, Colleen A. [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Qi, X. Sharon [Department of Radiation Oncology, University of Colorado Denver, Denver, Colorado (United States); Li, X. Allen, E-mail: ali@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)

    2012-04-01

    Purpose: In image-guided radiation therapy (IGRT), different computed tomography (CT) modalities with varying image quality are being used to correct for interfractional variations in patient set-up and anatomy changes, thereby reducing clinical target volume to the planning target volume (CTV-to-PTV) margins. We explore how CT image quality affects patient repositioning and CTV-to-PTV margins in soft tissue registration-based IGRT for prostate cancer patients. Methods and Materials: Four CT-based IGRT modalities used for prostate RT were considered in this study: MV fan beam CT (MVFBCT) (Tomotherapy), MV cone beam CT (MVCBCT) (MVision; Siemens), kV fan beam CT (kVFBCT) (CTVision, Siemens), and kV cone beam CT (kVCBCT) (Synergy; Elekta). Daily shifts were determined by manual registration to achieve the best soft tissue agreement. Effect of image quality on patient repositioning was determined by statistical analysis of daily shifts for 136 patients (34 per modality). Inter- and intraobserver variability of soft tissue registration was evaluated based on the registration of a representative scan for each CT modality with its corresponding planning scan. Results: Superior image quality with the kVFBCT resulted in reduced uncertainty in soft tissue registration during IGRT compared with other image modalities for IGRT. The largest interobserver variations of soft tissue registration were 1.1 mm, 2.5 mm, 2.6 mm, and 3.2 mm for kVFBCT, kVCBCT, MVFBCT, and MVCBCT, respectively. Conclusions: Image quality adversely affects the reproducibility of soft tissue-based registration for IGRT and necessitates a careful consideration of residual uncertainties in determining different CTV-to-PTV margins for IGRT using different image modalities.

  14. The early changes in bone mineral metabolism due to radiation; Measurement of bone mineral density in lumbar vertebra by quantitative computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Katsuyuki; Hori, Reiko; Shigekawa, Koji; Matsubara, Keiichi; Inoue, Yasuhiro; Matsuura, Shunpei; Kataoka, Masaaki; Kawamura, Masashi (Ehime Univ., Shigenobu (Japan). School of Medicine)

    1991-01-01

    Osteosclerosis, osteonecrosis and compression fracture are commonly observed several years after radiation. Since lumbago usually occurs several months after radiation, the possibility that bone mineral metabolism is disturbed during and immediately after radiation cannot be ruled out. However, there have been no reports concerning early changes in bone mineral metabolism due to radiation. The bone mineral density was measured by QCT (Quantitative Computed Tomography) in 30 normal non-radiated cases and 14 radiated cases to investigate the changes in bone mineral metabolism due to radiation. The bone mineral density (QCT-Value: QCT-V) in the 3rd lumbar vertebra (L3) of normal non-radiated subjects decreased linearly with age (Y=291.114447-3.01473X). The QCT-V of the 5th lumbar vertebra (L5) of normal cases also decreased linearly with age (Y=309.641397-3.03986X), resembling that of L3. The ratio of the QCT-V of L5 to L3 (L5/L3, expressed as a parcentage) definitely increased with age (Y=86.5657441+0.58885064X). In radiated cases, the QCT-V of L3 in the non-radiated field did not change appreciably. The QCT-V of L5 in the radiated field was decreased from 20 Gy and reached 53.08+-17.37% of the pre-radiation value after 50 Gy. The L5/L3 ratio was also decreased from 20 Gy and reached 55.47+-15.32% of the pre-radiation value after 50 Gy. It becomes apparent that the QCT-V of the radiated lumbar vertebra is decreased during radiation. It is suggested that bone mineral metabolism may be disturbed in the early phase of radiation. (author).

  15. Proton computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, K.M.

    1978-01-01

    The use of protons or other heavy charged particles instead of x rays in computed tomography (CT) is explored. The results of an experimental implementation of proton CT are presented. High quality CT reconstructions are obtained at an average dose reduction factor compared with an EMI 5005 x-ray scanner of 10:1 for a 30-cm-diameter phantom and 3.5:1 for a 20-cm diameter. The spatial resolution is limited by multiple Coulomb scattering to about 3.7 mm FWHM. Further studies are planned in which proton and x-ray images of fresh human specimens will be compared. Design considerations indicate that a clinically useful proton CT scanner is eminently feasible.

  16. Predicting oropharyngeal tumor volume throughout the course of radiation therapy from pretreatment computed tomography data using general linear models

    Science.gov (United States)

    Yock, Adam D.; Rao, Arvind; Dong, Lei; Beadle, Beth M.; Garden, Adam S.; Kudchadker, Rajat J.; Court, Laurence E.

    2014-01-01

    Purpose: The purpose of this work was to develop and evaluate the accuracy of several predictive models of variation in tumor volume throughout the course of radiation therapy. Methods: Nineteen patients with oropharyngeal cancers were imaged daily with CT-on-rails for image-guided alignment per an institutional protocol. The daily volumes of 35 tumors in these 19 patients were determined and used to generate (1) a linear model in which tumor volume changed at a constant rate, (2) a general linear model that utilized the power fit relationship between the daily and initial tumor volumes, and (3) a functional general linear model that identified and exploited the primary modes of variation between time series describing the changing tumor volumes. Primary and nodal tumor volumes were examined separately. The accuracy of these models in predicting daily tumor volumes were compared with those of static and linear reference models using leave-one-out cross-validation. Results: In predicting the daily volume of primary tumors, the general linear model and the functional general linear model were more accurate than the static reference model by 9.9% (range: −11.6%–23.8%) and 14.6% (range: −7.3%–27.5%), respectively, and were more accurate than the linear reference model by 14.2% (range: −6.8%–40.3%) and 13.1% (range: −1.5%–52.5%), respectively. In predicting the daily volume of nodal tumors, only the 14.4% (range: −11.1%–20.5%) improvement in accuracy of the functional general linear model compared to the static reference model was statistically significant. Conclusions: A general linear model and a functional general linear model trained on data from a small population of patients can predict the primary tumor volume throughout the course of radiation therapy with greater accuracy than standard reference models. These more accurate models may increase the prognostic value of information about the tumor garnered from pretreatment computed tomography

  17. Predicting oropharyngeal tumor volume throughout the course of radiation therapy from pretreatment computed tomography data using general linear models

    Energy Technology Data Exchange (ETDEWEB)

    Yock, Adam D., E-mail: ADYock@mdanderson.org; Kudchadker, Rajat J. [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas 77030 (United States); Rao, Arvind [Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and the Graduate School of Biomedical Sciences, the University of Texas Health Science Center at Houston, Houston, Texas 77030 (United States); Dong, Lei [Scripps Proton Therapy Center, San Diego, California 92121 and The Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas 77030 (United States); Beadle, Beth M.; Garden, Adam S. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Court, Laurence E. [Department of Radiation Physics and Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 and The Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas 77030 (United States)

    2014-05-15

    Purpose: The purpose of this work was to develop and evaluate the accuracy of several predictive models of variation in tumor volume throughout the course of radiation therapy. Methods: Nineteen patients with oropharyngeal cancers were imaged daily with CT-on-rails for image-guided alignment per an institutional protocol. The daily volumes of 35 tumors in these 19 patients were determined and used to generate (1) a linear model in which tumor volume changed at a constant rate, (2) a general linear model that utilized the power fit relationship between the daily and initial tumor volumes, and (3) a functional general linear model that identified and exploited the primary modes of variation between time series describing the changing tumor volumes. Primary and nodal tumor volumes were examined separately. The accuracy of these models in predicting daily tumor volumes were compared with those of static and linear reference models using leave-one-out cross-validation. Results: In predicting the daily volume of primary tumors, the general linear model and the functional general linear model were more accurate than the static reference model by 9.9% (range: −11.6%–23.8%) and 14.6% (range: −7.3%–27.5%), respectively, and were more accurate than the linear reference model by 14.2% (range: −6.8%–40.3%) and 13.1% (range: −1.5%–52.5%), respectively. In predicting the daily volume of nodal tumors, only the 14.4% (range: −11.1%–20.5%) improvement in accuracy of the functional general linear model compared to the static reference model was statistically significant. Conclusions: A general linear model and a functional general linear model trained on data from a small population of patients can predict the primary tumor volume throughout the course of radiation therapy with greater accuracy than standard reference models. These more accurate models may increase the prognostic value of information about the tumor garnered from pretreatment computed tomography

  18. Metrizamide computed tomography in syringomyelia

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, T.; Tamakawa, Y.; Arii, H. (Akita Univ. (Japan). Faculty of Medicine); Takahashi, M.; Hirota, K.

    1981-11-01

    Serial computed tomography of the cervical cord was performed following metrizamide myelography in five cases of clinically suspected syringomyelia. The syrinx filled with refluxed metrizamide was demonstrated in all of the cases. The reflux of metrizamide into the syrinx was most marked several hours following intrathecal injection of metrizamide. Computed tomography combined with metrizamide myelography is essential in the diagnosis of communicating syringomyelia.

  19. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) ...

  20. Computed tomography urography technique, indications and limitations.

    Science.gov (United States)

    Morcos, Sameh K

    2007-01-01

    The review discusses the different techniques of computed tomography urography reported in the literature and presents the author's preferred approach. Multiphase computed tomography urography offers a comprehensive evaluation of the urinary tract but at the cost of a large dose of contrast medium (100-150 ml), high radiation dose and massive number of images for interpretation. Diuresis induced by frusemide (10 mg) is reported to improve the depiction of ureters in the excretory phase of the examination. The author's preferred approach is a limited computed tomography urography which includes precontrast scanning of the kidneys, followed by an excretory phase 5 min after intravenous injection of 50 ml of contrast medium and 10 mg of frusemide. This limited examination in the author's experience provides a satisfactory evaluation of the urinary tract in the majority of patients, without inflicting a high radiation dose on the patient. A limited computed tomography urography examination is adequate for the majority of patients requiring excretory urography and a superior replacement of conventional intravenous urography. Information provided by a multiphase computed tomography urography examination is beneficial only in a small number of patients.

  1. Incorporating quantitative single photon emission computed tomography into radiation therapy treatment planning for lung cancer: impact of attenuation and scatter correction on the single photon emission computed tomography-weighted mean dose and functional lung segmentation.

    Science.gov (United States)

    Yin, Lingshu; Shcherbinin, Sergey; Celler, Anna; Thompson, Anna; Fua, Tsien-Fei; Liu, Mitchell; Duzenli, Cheryl; Gill, Brad; Sheehan, Finbar; Powe, John; Worsley, Daniel; Marks, Lawrence; Moiseenko, Vitali

    2010-10-01

    To assess the impact of attenuation and scatter corrections on the calculation of single photon emission computed tomography (SPECT)-weighted mean dose (SWMD) and functional volume segmentation as applied to radiation therapy treatment planning for lung cancer. Nine patients with lung cancer underwent a SPECT lung perfusion scan. For each scan, four image sets were reconstructed using the ordered subsets expectation maximization method with attenuation and scatter corrections ranging from none to a most comprehensive combination of attenuation corrections and direct scatter modeling. Functional volumes were segmented in each reconstructed image using 10%, 20%, …, 90% of maximum SPECT intensity as a threshold. Systematic effects of SPECT reconstruction methods on treatment planning using functional volume were studied by calculating size and spatial agreements of functional volumes, and V(20) for functional volume from actual treatment plans. The SWMD was calculated for radiation beams with a variety of possible gantry angles and field sizes. Functional volume segmentation is sensitive to the particular method of SPECT reconstruction used. Large variations in functional volumes, as high as >50%, were observed in SPECT images reconstructed with different attenuation/scatter corrections. However, SWMD was less sensitive to the type of scatter corrections. SWMD was consistent within 2% for all reconstructions as long as computed tomography-based attenuation correction was used. When using perfusion SPECT images during treatment planning optimization/evaluation, the SWMD may be the preferred figure of merit, as it is less affected by reconstruction technique, compared with threshold-based functional volume segmentation. 2010 Elsevier Inc. All rights reserved.

  2. Comparative of radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT, Cone-Beam CT (CBCT and periapical radiography in dental imaging

    Directory of Open Access Journals (Sweden)

    Nasrollah Jabbari

    2016-03-01

    Full Text Available Background and Aims: With the increasing use of CT (Computed Tomoghraphy scans in dentistry especially in the implantology, there may be significant increases in the radiation exposure and its risk. During the last year’s ConeBeam Computed Tomoghraphy (CBCT has been introduced as an imaging modality for dentistry. The aim of this review article was to present comprehensive information have been published, regarding the  radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT, Cone-Beam CT (CBCT and periapical radiography in dentistry imaging. Materials and Methods: A review of the literature was carried out in PubMed, Google Scholar, Science Direct and Scopus database using key words (CBCT, MSCT, periapical radiography, radiation dose of dentistry and image quality. These searches were limited to the articles published between the years of 1993 to 2015. Conclusion: In comparison to MSCT, CBCT had a short scanning times and lower radiation dose, but in comparison to periapical radiography, CBCT had higher radiation dose. In contrast, CBCT with flat panel detector had higher spatial resolution to MSCT. The periapical radiography also had a good image contrast and relatively high resolution. Generally, CBCT was suitable for hard tissue imaging and MSCT was preferred for soft tissue imaging.

  3. Odontoid Fracture: Computed Tomography

    Directory of Open Access Journals (Sweden)

    Jonathan Peña

    2016-09-01

    Full Text Available History of present illness: An 84-year-old male presented with left-sided posterior head, neck, and back pain after a ground level fall. Exam was notable for left parietal scalp laceration and midline cervical spine tenderness with no obvious deformities. He was neurovascularly intact, and placed in an Aspen Collar with strict spine precautions. Significant findings: Computed Tomography (CT of the cervical spine showed a stable, acute, non-displaced fracture of the odontoid process extending into the body of C2, consistent with a Type III Odontoid Fracture. He was evaluated by orthopedic spine service who recommended conservative, non-operative management. Discussion: The cervical spine is composed of seven vertebrae, with C1 and C2 commonly referred to as the Atlas and Axis, respectively. Unique to C2 is a bony prominence, the Odontoid Process (Dens. Hyperextension or hyperflexion injuries can induce significant stress causing fractures. Odontoid fractures comprise approximately 10% of vertebral fractures, and there are three types with varying stability.1 Type 1 is the rarest and is a fracture involving the superior segment of the Dens. It is considered a stable fracture. Type 2 is the most common and is a fracture involving the base of the odontoid process, below the transverse component of the cruciform ligament. This fracture is unstable and requires operative stabilization. 2 Type 3 odontoid fractures are classified by a fracture of the Odontoid process, as well as the lateral masses of the C2. Determining the stability of a Type III Odontoid fracture requires radiographic evaluation. Strict cervical spine precautions must be adhered to until adequate imaging and surgical consultation is obtained. CT of the of cervical spine fractures poses several advantages to plain film radiography due to the ability to view the anatomy in three planes. 3 However, if there is concern for ligamentous injury, MRI is the preferred modality.3

  4. Impact of reduced-radiation dual-energy protocols using 320-detector row computed tomography for analyzing urinary calculus components: initial in vitro evaluation.

    Science.gov (United States)

    Cai, Xiangran; Zhou, Qingchun; Yu, Juan; Xian, Zhaohui; Feng, Youzhen; Yang, Wencai; Mo, Xukai

    2014-10-01

    To evaluate the impact of reduced-radiation dual-energy (DE) protocols using 320-detector row computed tomography on the differentiation of urinary calculus components. A total of 58 urinary calculi were placed into the same phantom and underwent DE scanning with 320-detector row computed tomography. Each calculus was scanned 4 times with the DE protocols using 135 kV and 80 kV tube voltage and different tube current combinations, including 100 mA and 570 mA (group A), 50 mA and 290 mA (group B), 30 mA and 170 mA (group C), and 10 mA and 60 mA (group D). The acquisition data of all 4 groups were then analyzed by stone DE analysis software, and the results were compared with x-ray diffraction analysis. Noise, contrast-to-noise ratio, and radiation dose were compared. Calculi were correctly identified in 56 of 58 stones (96.6%) using group A and B protocols. However, only 35 stones (60.3%) and 16 stones (27.6%) were correctly diagnosed using group C and D protocols, respectively. Mean noise increased significantly and mean contrast-to-noise ratio decreased significantly from groups A to D (P calculus component analysis while reducing patient radiation exposure to 1.81 mSv. Further reduction of tube currents may compromise diagnostic accuracy. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. The Evolving Mcart Multimodal Imaging Core: Establishing a Protocol for Computed Tomography and Echocardiography in the Rhesus Macaque to Perform Longitudinal Analysis of Radiation-Induced Organ Injury.

    Science.gov (United States)

    de Faria, Eduardo B; Barrow, Kory R; Ruehle, Bradley T; Parker, Jordan T; Swartz, Elisa; Taylor-Howell, Cheryl; Kieta, Kaitlyn M; Lees, Cynthia J; Sleeper, Meg M; Dobbin, Travis; Baron, Adam D; Mohindra, Pranshu; MacVittie, Thomas J

    2015-11-01

    Computed Tomography (CT) and Echocardiography (EC) are two imaging modalities that produce critical longitudinal data that can be analyzed for radiation-induced organ-specific injury to the lung and heart. The Medical Countermeasures Against Radiological Threats (MCART) consortium has a well established animal model research platform that includes nonhuman primate (NHP) models of the acute radiation syndrome and the delayed effects of acute radiation exposure. These models call for a definition of the latency, incidence, severity, duration, and resolution of different organ-specific radiation-induced subsyndromes. The pulmonary subsyndromes and cardiac effects are a pair of interdependent syndromes impacted by exposure to potentially lethal doses of radiation. Establishing a connection between these will reveal important information about their interaction and progression of injury and recovery. Herein, the authors demonstrate the use of CT and EC data in the rhesus macaque models to define delayed organ injury, thereby establishing: a) consistent and reliable methodology to assess radiation-induced damage to the lung and heart; b) an extensive database in normal age-matched NHP for key primary and secondary endpoints; c) identified problematic variables in imaging techniques and proposed solutions to maintain data integrity; and d) initiated longitudinal analysis of potentially lethal radiation-induced damage to the lung and heart.

  6. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... What are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as ... top of page What are some common uses of the procedure? CT is used to help diagnose ...

  7. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... Pediatric computed tomography (CT) is a fast, painless exam that uses special x-ray equipment to create ... your doctor and the technologist prior to the exam if your child has a known allergy to ...

  8. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... risks? What are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known ... newborns, infants and older children. top of page What are some common uses of the procedure? CT ...

  9. Improving radiation awareness and feeling of personal security of non-radiological medical staff by implementing a traffic light system in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Heilmaier, C.; Mayor, A.; Zuber, N.; Weishaupt, D. [Stadtspital Triemli, Zurich (Switzerland). Dept. of Radiology; Fodor, P. [Stadtspital Triemli, Zurich (Switzerland). Dept. of Anesthesiology and Intensive Care Medicine

    2016-03-15

    Non-radiological medical professionals often need to remain in the scanning room during computed tomography (CT) examinations to supervise patients in critical condition. Independent of protective devices, their position significantly influences the radiation dose they receive. The purpose of this study was to assess if a traffic light system indicating areas of different radiation exposure improves non-radiological medical staff's radiation awareness and feeling of personal security. Phantom measurements were performed to define areas of different dose rates and colored stickers were applied on the floor according to a traffic light system: green = lowest, orange = intermediate, and red = highest possible radiation exposure. Non-radiological medical professionals with different years of working experience evaluated the system using a structured questionnaire. Kruskal-Wallis and Spearman's correlation test were applied for statistical analysis. Fifty-six subjects (30 physicians, 26 nursing staff) took part in this prospective study. Overall rating of the system was very good, and almost all professionals tried to stand in the green stickers during the scan. The system significantly increased radiation awareness and feeling of personal protection particularly in staff with ? 5 years of working experience (p < 0.05). The majority of non-radiological medical professionals stated that staying in the green stickers and patient care would be compatible. Knowledge of radiation protection was poor in all groups, especially among entry-level employees (p < 0.05). A traffic light system in the CT scanning room indicating areas with lowest, in-termediate, and highest possible radiation exposure is much appreciated. It increases radiation awareness, improves the sense of personal radiation protection, and may support endeavors to lower occupational radiation exposure, although the best radiation protection always is to re-main outside the CT room during the scan.

  10. Computed Tomography (CT) -- Head

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    Full Text Available ... tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

  11. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like ... imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  12. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

  13. Computed Tomography (CT) -- Head

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    Full Text Available ... skull or to plan radiation therapy for brain cancer. In emergency cases, it can reveal internal injuries ... in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. guide the ...

  14. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ... RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page This page was reviewed on ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... scans in children should always be done with low-dose technique. top of page What are the ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  16. Computed Tomography (CT) -- Head

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    Full Text Available ... your face, sinuses, and skull or to plan radiation therapy for brain cancer. In emergency cases, it can ... changes are present in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. ...

  17. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... can be performed if you have an implanted medical device of any kind, unlike MRI. CT imaging provides ... radiation dose for this procedure varies. See the Safety page for more information about radiation dose. Women ...

  18. Computed Tomography (CT) -- Head

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    Full Text Available ... can be performed if you have an implanted medical device of any kind, unlike MRI. A diagnosis determined ... radiation dose for this procedure varies. See the Safety page for more information about radiation dose. Women ...

  19. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... Head and Neck Cancer Treatment Radiation Dose in X-Ray and CT Exams Contrast Materials Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images ...

  20. Computed Tomography (CT) -- Head

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    Full Text Available ... medical device of any kind, unlike MRI. A diagnosis determined by CT scanning may eliminate the need ... to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. The effective radiation dose ...

  1. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... particularly the lungs, abdomen, pelvis and bones. A diagnosis determined by CT scanning may eliminate the need ... to radiation. However, the benefit of an accurate diagnosis far outweighs the risk. The effective radiation dose ...

  2. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page This page was reviewed ... Media Magnetic Resonance Imaging (MRI) - Head Head and Neck Cancer Treatment Radiation Dose in X-Ray and ...

  3. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... conventional x-ray exam, a small amount of radiation is aimed at and passes through the part ... detectors rotate around you, measuring the amount of radiation being absorbed throughout your body. Sometimes, the examination ...

  4. Computed Tomography (CT) -- Head

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    Full Text Available ... your face, sinuses, and skull or to plan radiation therapy for brain cancer. In emergency cases, it ... changes are present in the paranasal sinuses. plan radiation therapy for cancer of the brain or other ...

  5. Comparison of the radiation dose from cone beam computed tomography and multidetector computed tomography in examinations of the hand; Vergleich der Strahlendosis von Cone-Beam Computertomografie und Multidetektor Computertomografie in Untersuchungen der Hand

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, J.; Neubauer, C.; Gerstmair, A.; Krauss, T.; Kotter, E.; Langer, M. [University Medical Center Freiburg (Germany). Dept. of Radiology; Reising, K. [University Medical Center Freiburg (Germany). Dept. of Orthopedics and Trauma Surgery; Zajonc, H. [University Medical Center Freiburg (Germany). Dept. of Plastic and Hand Surgery; Fiebich, M.; Voigt, J. [University of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection

    2016-05-15

    Comparison of radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in examinations of the hand. Dose calculations were carried out by means of Monte Carlo simulations in MDCT and CBCT. A corpse hand was examined in a 320-row MDCT scanner and a dedicated extremities CBCT scanner with standard protocols and multiple low-dose protocols. The image quality of the examinations was evaluated by 5 investigators using a Likert scale from 1 (very good) to 5 (very poor) regarding depiction of cortical bone, cancellous bone, joint surfaces, soft tissues and artifacts. For a sum of ratings of all structures < 50 a good overall image quality was expected. The studies with at least good overall image quality were compared with respect to the dose. The dose of the standard examination was 13.21 (12.96 to 13.46 CI) mGy in MDCT and 7.15 (6.99 to 7.30 CI) mGy in CBCT. The lowest dose in a study with good overall image quality was 4.54 (4.43 to 4.64 CI) mGy in MDCT and 5.72 (5.59 to 5.85 CI) mGy in CBCT. Although the dose of the standard protocols in the CBCT is lower than in the MDCT, the MDCT can realize a good overall image quality at a lower dose than the CBCT. Dose optimization of CT examination protocols for the hand is useful in both modalities, the MDCT has an even greater potential for optimization.

  6. Computed Tomography in the Evaluation of Cystic Fibrosis Lung Disease

    National Research Council Canada - National Science Library

    Brody, Alan S; Tiddens, Harm A. W. M; Castile, Robert G; Coxson, Harvey O; de Jong, Pim A; Goldin, Jonathan; Huda, Walter; Long, Frederick R; McNitt-Gray, Michael; Rock, Michael; Robinson, Terry E; Sagel, Scott D; CT Scanning in Cystic Fibrosis Special Interest Group

    2005-01-01

    ... of this article is to present the current status of CT scanning in CF. Keywords: computed tomography X-ray; cystic fibrosis; radiation effects; research design The first report of computed tomography (CT) scanning to monitor cystic fibrosis (CF)-related lung disease was published in 1986 (1). Further publications followed, but in general there was little i...

  7. Cone beam computed tomography in Endodontics - a review

    NARCIS (Netherlands)

    Patel, S.; Durack, C.; Abella, F.; Shemesh, H.; Roig, M.; Lemberg, K.

    2015-01-01

    Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on

  8. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation ... costs for specific medical imaging tests, treatments and procedures may vary by geographic region. ...

  9. Computed Tomography (CT) -- Head

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    Full Text Available ... and surgical biopsy. No radiation remains in a patient's body after a CT examination. X-rays used in CT scans should have no immediate side effects. Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  10. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... and surgical biopsy. No radiation remains in a patient's body after a CT examination. X-rays used in CT scans should have no immediate side effects. Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  11. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page This page was reviewed on June 21, 2016 Send us your feedback Did you find the information you were looking for? Yes ... Resonance Imaging (MRI) - Head Head and Neck Cancer Treatment Radiation Dose in X-Ray and CT Exams Contrast ...

  12. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much like other x-ray examinations. Different ... radiation dose for this procedure varies. See the Safety page for more information about radiation dose. Women ...

  13. Computed Tomography (CT) -- Head

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    Full Text Available ... microphone. top of page How does the procedure work? In many ways CT scanning works very much like other x-ray examinations. Different ... radiation dose for this procedure varies. See the Safety page for more information about radiation dose. Women ...

  14. Computed Tomography (CT) -- Head

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    Full Text Available ... and skull or to plan radiation therapy for brain cancer. In emergency cases, it can reveal internal injuries ... in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. guide the passage of a ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... ring, called a gantry. The computer workstation that processes the imaging information is located in a separate ... follows a spiral path. A special computer program processes this large volume of data to create two- ...

  16. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... ring, called a gantry. The computer workstation that processes the imaging information is located in a separate ... follows a spiral path. A special computer program processes this large volume of data to create two- ...

  17. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... images. These images can be viewed on a computer monitor, printed on film or transferred to a ... other in a ring, called a gantry. The computer workstation that processes the imaging information is located ...

  18. Computed Tomography (CT) -- Head

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    Full Text Available ... images. These images can be viewed on a computer monitor, printed on film or transferred to a ... other in a ring, called a gantry. The computer workstation that processes the imaging information is located ...

  19. Effects of a radiation dose reduction strategy for computed tomography in severely injured trauma patients in the emergency department: an observational study

    Directory of Open Access Journals (Sweden)

    Kim Soo Hyun

    2011-11-01

    Full Text Available Abstract Background Severely injured trauma patients are exposed to clinically significant radiation doses from computed tomography (CT imaging in the emergency department. Moreover, this radiation exposure is associated with an increased risk of cancer. The purpose of this study was to determine some effects of a radiation dose reduction strategy for CT in severely injured trauma patients in the emergency department. Methods We implemented the radiation dose reduction strategy in May 2009. A prospective observational study design was used to collect data from patients who met the inclusion criteria during this one year study (intervention group from May 2009 to April 2010. The prospective data were compared with data collected retrospectively for one year prior to the implementation of the radiation dose reduction strategy (control group. By comparison of the cumulative effective dose and the number of CT examinations in the two groups, we evaluated effects of a radiation dose reduction strategy. All the patients met the institutional adult trauma team activation criteria. The radiation doses calculated by the CT scanner were converted to effective doses by multiplication by a conversion coefficient. Results A total of 118 patients were included in this study. Among them, 33 were admitted before May 2009 (control group, and 85 were admitted after May 2009 (intervention group. There were no significant differences between the two groups regarding baseline characteristics, such as injury severity and mortality. Additionally, there was no difference between the two groups in the mean number of total CT examinations per patient (4.8 vs. 4.5, respectively; p = 0.227. However, the mean effective dose of the total CT examinations per patient significantly decreased from 78.71 mSv to 29.50 mSv (p Conclusions The radiation dose reduction strategy for CT in severely injured trauma patients effectively decreased the cumulative effective dose of the total

  20. Computed Tomography (CT) -- Head

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... Safety page for more information about radiation dose. Women should always inform their physician and x-ray ...

  1. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... Safety page for more information about radiation dose. Women should always inform their physician and x-ray ...

  2. Computed Tomography (CT) -- Head

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    Full Text Available ... you! Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to ...

  3. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... you! Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... Materials Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to ...

  4. Computed Tomography (CT) -- Head

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    Full Text Available ... and other symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor to evaluate ... and skull or to plan radiation therapy for brain cancer. In emergency cases, it can reveal internal ...

  5. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... of the nasal cavity and sinuses. plan for surgery by defining anatomy. top of page How should ... CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a ...

  6. Computed Tomography (CT) -- Head

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    Full Text Available ... to plan radiation therapy for brain cancer. In emergency cases, it can reveal internal injuries and bleeding ... vessels. CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding ...

  7. Computed Tomography (CT) -- Head

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    Full Text Available ... small amount of radiation is aimed at and passes through the part of the body being examined, ... of CT scan, the machine may make several passes. You may be asked to hold your breath ...

  8. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... small amount of radiation is aimed at and passes through the part of the body being examined, ... of CT scan, the machine may make several passes. You may be asked to hold your breath ...

  9. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... will be adjusted to their size and the area of interest to reduce the radiation dose. For ... material is used to enhance visibility in the area of the body being studied. top of page ...

  10. Computed Tomography (CT) -- Head

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    Full Text Available ... will be adjusted to their size and the area of interest to reduce the radiation dose. For ... material is used to enhance visibility in the area of the body being studied. top of page ...

  11. Computed Tomography (CT) -- Head

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    Full Text Available ... symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor to evaluate your face, ... radiation therapy for brain cancer. In emergency cases, it can reveal internal injuries and bleeding quickly enough ...

  12. Computed Tomography (CT) -- Head

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    Full Text Available ... membranes covering the brain. top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Brain ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  13. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... scans in children should always be done with low-dose technique. top of page What are the ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page ...

  14. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... for the moving table. top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... shield may stay in the room with their child. However, the technologist will always be able to ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose ...

  16. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... many areas of the body, particularly the lungs, abdomen, pelvis and bones. A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a ...

  17. Computed Tomography (CT) -- Head

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    Full Text Available ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety ... information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. ...

  18. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Magnetic Resonance Imaging (MRI) - Head Head and Neck Cancer Treatment Radiation Dose in X-Ray and CT ...

  19. Computed Tomography (CT) -- Head

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    Full Text Available ... CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X- ...

  20. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the ... eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body after ...

  1. Computed Tomography (CT) -- Head

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    Full Text Available ... a needle used to obtain a tissue sample ( biopsy ) from the brain. assess aneurysms or arteriovenous malformations ... eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body after ...

  2. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. When ... Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page This page was reviewed ...

  3. Computed Tomography (CT) -- Head

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    Full Text Available ... sometimes compared to looking into a loaf of bread by cutting the loaf into thin slices. When ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others American Stroke Association National Stroke Association ...

  4. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... presence of inflammatory diseases. provide additional information about tumors of the nasal cavity and sinuses. plan for ... Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  5. Computed Tomography (CT) -- Head

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    Full Text Available ... other symptoms of aneurysm, bleeding, stroke and brain tumors. It also helps your doctor to evaluate your ... skull or to plan radiation therapy for brain cancer. In emergency cases, it can reveal internal injuries ...

  6. Computed Tomography (CT) -- Head

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... membranes covering the brain. top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Brain ...

  7. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... for the moving table. top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head ...

  8. Computed Tomography (CT) -- Head

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and ...

  9. Computed Tomography (CT) -- Head

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    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  10. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Risks There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit ...

  11. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... face-down with the chin elevated. Straps and pillows may be used to help the patient maintain ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  12. Computed Tomography (CT) -- Sinuses

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    ... face-down with the chin elevated. Straps and pillows may be used to help the patient maintain ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  13. Computed Tomography (CT) -- Head

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    Full Text Available ... usually lying flat on your back. Straps and pillows may be used to help you maintain the ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  14. Computed Tomography (CT) -- Head

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    ... usually lying flat on your back. Straps and pillows may be used to help you maintain the ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... and pillows may be used to help you maintain the correct position and to help you remain ... Safety page for more information about radiation dose. Women should always inform their physician and x-ray ...

  16. Computed Tomography (CT) -- Head

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    Full Text Available ... used to detect: bleeding, brain injury and skull fractures in patients with head injuries. bleeding caused by ... are present in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. ...

  17. Computed Tomography (CT) -- Head

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    Full Text Available ... side of the skull, which may be causing hearing problems. determine whether inflammation or other changes are present in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. ...

  18. Using 100- instead of 120-kVp computed tomography to diagnose pulmonary embolism almost halves the radiation dose with preserved diagnostic quality

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerkdahl, Peter; Nyman, Ulf (Dept. of Radiology, Univ. of Lund, Lasarettet Trelleborg, Trelleborg (Sweden)), e-mail: ulf.nyman@skane.se

    2010-04-15

    Background: Concern has been raised regarding the mounting collective radiation doses from computed tomography (CT), increasing the risk of radiation-induced cancers in exposed populations. Purpose: To compare radiation dose and image quality in a chest phantom and in patients for the diagnosis of pulmonary embolism (PE) at 100 and 120 peak kilovoltage (kVp) using 16-multichannel detector computed tomography (MDCT). Material and Methods: A 20-ml syringe containing 12 mg I/ml was scanned in a chest phantom at 100/120 kVp and 25 milliampere seconds (mAs). Consecutive patients underwent 100 kVp (n = 50) and 120 kVp (n = 50) 16-MDCT using a 'quality reference' effective mAs of 100, 300 mg I/kg, and a 12-s injection duration. Attenuation (CT number), image noise (1 standard deviation), and contrast-to-noise ratio (CNR; fresh clot = 70 HU) of the contrast medium syringe and pulmonary arteries were evaluated on 3-mm-thick slices. Subjective image quality was assessed. Computed tomography dose index (CTDIvol) and dose-length product (DLP) were presented by the CT software, and effective dose was estimated. Results: Mean values in the chest phantom and patients changed as follows when X-ray tube potential decreased from 120 to 100 kVp: attenuation +23% and +40%, noise +38% and +48%, CNR -6% and 0%, and CTDIvol -38% and -40%, respectively. Mean DLP and effective dose in the patients decreased by 42% and 45%, respectively. Subjective image quality was excellent or adequate in 49/48 patients at 100/120 kVp. No patient with a negative CT had any thromboembolism diagnosed during 3-month follow-up. Conclusion: By reducing X-ray tube potential from 120 to 100 kVp, while keeping all other scanning parameters unchanged, the radiation dose to the patient may be almost halved without deterioration of diagnostic quality, which may be of particular benefit in young individuals

  19. Automated tube voltage selection in thoracoabdominal computed tomography at high pitch using a third-generation dual-source scanner: image quality and radiation dose performance.

    Science.gov (United States)

    Lurz, Markus; Lell, Michael M; Wuest, Wolfgang; Eller, Achim; Scharf, Michael; Uder, Michael; May, Matthias Stefan

    2015-05-01

    The objective of this study was to evaluate the radiation dose and image quality performance of thoracoabdominal examinations with an automated tube voltage selection (tube voltage adaptation), tube current modulation, and high pitch using a third-generation dual-source computed tomography (CT) compared intraindividually with 120-kV examinations with tube current modulation with special attention on clinically relevant lesions in the liver, the lungs, and extrahepatic soft tissues. This study was approved by the institutional review board. Computed tomography of the body was performed using a third-generation dual-source system in 95 patients (mean body mass index, 25 kg/m²; range, 18-35 kg/m²). For 49 of these patients, all calculated tube settings and resulting dose values were recorded for each of the 12 gradual contrast weightings of the tube voltage adaptation algorithm. Spiral CT was performed for all patients with an intermediate weighting (grade 7) in a portal venous phase at 120 reference kV, 180 reference mAs, and pitch of 1.55. Objective image quality was assessed on the basis of contrast-to-noise ratio. Subjective image quality was assessed on the basis of clarity and sharpness of anatomical and pathological structures as well as interfering beam hardening and spiral and motion artifacts (heart, lungs, diaphragm). Previous examinations on a 64-slice scanner served as reference. All examinations were rated good or excellent for clinical diagnosis. Automated tube voltage selection resulted in significantly lower effective radiation dose (9.5 mSv) compared with the reference (12.0 mSv; P radiation dose reduction while substantially increasing the image quality, even at large-volume exposure.

  20. Effects of a radiation dose reduction strategy for computed tomography in severely injured trauma patients in the emergency department: an observational study.

    Science.gov (United States)

    Kim, Soo Hyun; Jung, Seung Eun; Oh, Sang Hoon; Park, Kyu Nam; Youn, Chun Song

    2011-11-03

    Severely injured trauma patients are exposed to clinically significant radiation doses from computed tomography (CT) imaging in the emergency department. Moreover, this radiation exposure is associated with an increased risk of cancer. The purpose of this study was to determine some effects of a radiation dose reduction strategy for CT in severely injured trauma patients in the emergency department. We implemented the radiation dose reduction strategy in May 2009. A prospective observational study design was used to collect data from patients who met the inclusion criteria during this one year study (intervention group) from May 2009 to April 2010. The prospective data were compared with data collected retrospectively for one year prior to the implementation of the radiation dose reduction strategy (control group). By comparison of the cumulative effective dose and the number of CT examinations in the two groups, we evaluated effects of a radiation dose reduction strategy. All the patients met the institutional adult trauma team activation criteria. The radiation doses calculated by the CT scanner were converted to effective doses by multiplication by a conversion coefficient. A total of 118 patients were included in this study. Among them, 33 were admitted before May 2009 (control group), and 85 were admitted after May 2009 (intervention group). There were no significant differences between the two groups regarding baseline characteristics, such as injury severity and mortality. Additionally, there was no difference between the two groups in the mean number of total CT examinations per patient (4.8 vs. 4.5, respectively; p = 0.227). However, the mean effective dose of the total CT examinations per patient significantly decreased from 78.71 mSv to 29.50 mSv (p trauma patients effectively decreased the cumulative effective dose of the total CT examinations in the emergency department. But not effectively decreased the number of CT examinations.

  1. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... lie still is reduced. Though the scanning itself causes no pain, there may be some discomfort from ... of many areas of the body, particularly the lungs, abdomen, pelvis and bones. A ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  2. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... denotes child-specific content. Related Articles and Media Magnetic Resonance Imaging (MRI) - Head Head and Neck Cancer Treatment Radiation Dose in X-Ray and CT Exams Contrast Materials Head and Neck Cancer X-ray, Interventional Radiology ...

  3. Computed Tomography (CT) -- Head

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... View full size with caption Pediatric Content Some imaging tests ... Radiation Dose in X-Ray and CT Exams Blood Clots CT Perfusion of ...

  4. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ... specific content. Related Articles and Media Magnetic Resonance Imaging (MRI) - Head Head and Neck Cancer Treatment Radiation Dose in X-Ray and CT Exams Contrast Materials Head and Neck ...

  5. Computed Tomography (CT) -- Head

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    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... or any disorder of the heart, kidneys or thyroid gland , or if you ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  6. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of an unusual ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  7. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces ... of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  8. Computed Tomography (CT) -- Head

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    Full Text Available ... as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces ... in the paranasal sinuses. plan radiation therapy for cancer ... kidney disease or thyroid problems. Any of these conditions may increase the ...

  9. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck ... No Please type your comment or suggestion into the following text ...

  10. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top of page This page was reviewed on June 21, 2016 Send us your feedback Did you find the information you were looking for? Yes No Please type your comment or suggestion into the following text ...

  11. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... tissue, such as organs like the heart or liver, shows up in shades of gray, and ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  12. Computed Tomography (CT) -- Head

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    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... tissue, such as organs like the heart or liver, shows up in shades of gray, and ... chance of cancer from excessive exposure to radiation. However, the benefit ...

  13. Computed Tomography (CT) -- Head

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    Full Text Available ... can be performed if you have an implanted medical device of any kind, unlike MRI. A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  14. Computed Tomography (CT) -- Head

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    Full Text Available ... The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and ... by Please note RadiologyInfo.org is not a medical facility. Please contact your physician with specific medical ...

  15. Computed Tomography (CT) -- Head

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    Full Text Available ... with a new technique called Perfusion CT. brain tumors. enlarged brain cavities (ventricles) in patients with hydrocephalus . diseases or ... in the paranasal sinuses. plan radiation therapy for cancer of the brain or other tissues. guide the passage of a ...

  16. Computed Tomography (CT) -- Head

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    Full Text Available ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Blood Clots CT Perfusion of the Head CT Angiography ( ...

  17. Radiation Exposure of Interventional Radiologists During Computed Tomography Fluoroscopy-Guided Renal Cryoablation and Lung Radiofrequency Ablation: Direct Measurement in a Clinical Setting

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Yusuke, E-mail: wckyh140@yahoo.co.jp; Hiraki, Takao, E-mail: takaoh@tc4.so-net.ne.jp; Gobara, Hideo, E-mail: gobara@cc.okayama-u.ac.jp; Iguchi, Toshihiro, E-mail: i10476@yahoo.co.jp; Fujiwara, Hiroyasu, E-mail: hirofujiwar@gmail.com; Kawabata, Takahiro, E-mail: tkhr-kwbt@yahoo.co.jp [Okayama University Medical School, Department of Radiology (Japan); Yamauchi, Takatsugu, E-mail: me9248@hp.okayama-u.ac.jp; Yamaguchi, Takuya, E-mail: me8738@hp.okayama-u.ac.jp [Okayama University Hospital, Central Division of Radiology (Japan); Kanazawa, Susumu, E-mail: susumu@cc.okayama-u.ac.jp [Okayama University Medical School, Department of Radiology (Japan)

    2016-06-15

    IntroductionComputed tomography (CT) fluoroscopy-guided renal cryoablation and lung radiofrequency ablation (RFA) have received increasing attention as promising cancer therapies. Although radiation exposure of interventional radiologists during these procedures is an important concern, data on operator exposure are lacking.Materials and MethodsRadiation dose to interventional radiologists during CT fluoroscopy-guided renal cryoablation (n = 20) and lung RFA (n = 20) was measured prospectively in a clinical setting. Effective dose to the operator was calculated from the 1-cm dose equivalent measured on the neck outside the lead apron, and on the left chest inside the lead apron, using electronic dosimeters. Equivalent dose to the operator’s finger skin was measured using thermoluminescent dosimeter rings.ResultsThe mean (median) effective dose to the operator per procedure was 6.05 (4.52) μSv during renal cryoablation and 0.74 (0.55) μSv during lung RFA. The mean (median) equivalent dose to the operator’s finger skin per procedure was 2.1 (2.1) mSv during renal cryoablation, and 0.3 (0.3) mSv during lung RFA.ConclusionRadiation dose to interventional radiologists during renal cryoablation and lung RFA were at an acceptable level, and in line with recommended dose limits for occupational radiation exposure.

  18. Radiation dose considerations by intra-individual Monte Carlo simulations in dual source spiral coronary computed tomography angiography with electrocardiogram-triggered tube current modulation and adaptive pitch

    Energy Technology Data Exchange (ETDEWEB)

    May, Matthias S.; Kuettner, Axel; Lell, Michael M.; Wuest, Wolfgang; Scharf, Michael; Uder, Michael [University of Erlangen, Department of Radiology, Erlangen (Germany); Deak, Paul; Kalender, Willi A. [University of Erlangen, Department of Medical Physics, Erlangen (Germany); Keller, Andrea K.; Haeberle, Lothar [University of Erlangen, Department of Medical Informatics, Biometry and Epidemiology, Erlangen (Germany); Achenbach, Stephan; Seltmann, Martin [University of Erlangen, Department of Cardiology, Erlangen (Germany)

    2012-03-15

    To evaluate radiation dose levels in patients undergoing spiral coronary computed tomography angiography (CTA) on a dual-source system in clinical routine. Coronary CTA was performed for 56 patients with electrocardiogram-triggered tube current modulation (TCM) and heart-rate (HR) dependent pitch adaptation. Individual Monte Carlo (MC) simulations were performed for dose assessment. Retrospective simulations with constant tube current (CTC) served as reference. Lung tissue was segmented and used for organ and effective dose (ED) calculation. Estimates for mean relative ED was 7.1 {+-} 2.1 mSv/100 mAs for TCM and 12.5 {+-} 5.3 mSv/100 mAs for CTC (P < 0.001). Relative dose reduction at low HR ({<=}60 bpm) was highest (49 {+-} 5%) compared to intermediate (60-70 bpm, 33 {+-} 12%) and high HR (>70 bpm, 29 {+-} 12%). However lowest ED is achieved at high HR (5.2 {+-} 1.5 mSv/100 mAs), compared with intermediate (6.7 {+-} 1.6 mSv/100 mAs) and low (8.3 {+-} 2.1 mSv/100 mAs) HR when automated pitch adaptation is applied. Radiation dose savings up to 52% are achievable by TCM at low and regular HR. However lowest ED is attained at high HR by pitch adaptation despite inferior radiation dose reduction by TCM. circle Monte Carlo simulations allow for individual radiation dose calculations. (orig.)

  19. Radiation dose reduction using a CdZnTe-based computed tomography system: comparison to flat-panel detectors.

    Science.gov (United States)

    Le Huy, Q; Ducote, Justin L; Molloi, Sabee

    2010-03-01

    Although x-ray projection mammography has been very effective in early detection of breast cancer, its utility is reduced in the detection of small lesions that are occult or in dense breasts. One drawback is that the inherent superposition of parenchymal structures makes visualization of small lesions difficult. Breast computed tomography using flat-panel detectors has been developed to address this limitation by producing three-dimensional data while at the same time providing more comfort to the patients by eliminating breast compression. Flat panels are charge integrating detectors and therefore lack energy resolution capability. Recent advances in solid state semiconductor x-ray detector materials and associated electronics allow the investigation of x-ray imaging systems that use a photon counting and energy discriminating detector, which is the subject of this article. A small field-of-view computed tomography (CT) system that uses CdZnTe (CZT) photon counting detector was compared to one that uses a flat-panel detector for different imaging tasks in breast imaging. The benefits afforded by the CZT detector in the energy weighting modes were investigated. Two types of energy weighting methods were studied: Projection based and image based. Simulation and phantom studies were performed with a 2.5 cm polymethyl methacrylate (PMMA) cylinder filled with iodine and calcium contrast objects. Simulation was also performed on a 10 cm breast specimen. The contrast-to-noise ratio improvements as compared to flat-panel detectors were 1.30 and 1.28 (projection based) and 1.35 and 1.25 (image based) for iodine over PMMA and hydroxylapatite over PMMA, respectively. Corresponding simulation values were 1.81 and 1.48 (projection based) and 1.85 and 1.48 (image based). Dose reductions using the CZT detector were 52.05% and 49.45% for iodine and hydroxyapatite imaging, respectively. Image-based weighting was also found to have the least beam hardening effect. The results

  20. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  1. Computed Tomography (CT) -- Head

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    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... distinguished from one another on an x-ray film or CT electronic image. In a conventional x- ...

  2. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... images can be viewed on a computer monitor, printed on film or transferred to a CD or ... or blood vessels. A nurse or technologist will insert an intravenous (IV) line into a small vein ...

  3. Computed Tomography (CT) -- Head

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    Full Text Available ... slices. When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ...

  4. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... slices. When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body's interior. Refinements in detector technology allow nearly all CT scanners to obtain multiple ...

  5. Computed Tomography (CT) -- Head

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... speak with you through a built-in intercom system. With pediatric patients, a parent may be allowed ...

  6. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... speak with you through a built-in intercom system. With pediatric patients, a parent may be allowed ...

  7. Computed Tomography (CT) -- Head

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... Privacy | Terms of Use | Links | Site Map Copyright © 2017 Radiological Society of North America, Inc. (RSNA). To ...

  8. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... Privacy | Terms of Use | Links | Site Map Copyright © 2017 Radiological Society of North America, Inc. (RSNA). To ...

  9. Computed Tomography (CT) -- Head

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    Full Text Available ... appears black. With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors ... during the scan, so that the x-ray beam follows a spiral path. A special computer program ...

  10. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... appears black. With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors ... during the scan, so that the x-ray beam follows a spiral path. A special computer program ...

  11. Computed Tomography (CT) -- Head

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... If contrast material is used, depending on the type of exam, it will be swallowed, injected through ...

  12. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... actual CT scanning is performed. Depending on the type of CT scan, the machine may make several ...

  13. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 Radiological Society of North America, Inc. (RSNA). ...

  14. Computed Tomography (CT) -- Head

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 Radiological Society of North America, Inc. (RSNA). ...

  15. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... special computer program processes this large volume of data to create two-dimensional cross-sectional images of ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  16. Computed Tomography (CT) -- Head

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    Full Text Available ... special computer program processes this large volume of data to create two-dimensional cross-sectional images of ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  17. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... artifacts on the images. This loss of image quality can resemble the blurring seen on a photograph ...

  18. Computed Tomography (CT) -- Head

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    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... cause blurring of the images and degrade the quality of the examination the same way that it ...

  19. Computed Tomography (CT) -- Head

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    Full Text Available ... These images can be viewed on a computer monitor, printed on film or transferred to a CD ... room, where the technologist operates the scanner and monitors your examination in direct visual contact and usually ...

  20. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... These images can be viewed on a computer monitor, printed on film or transferred to a CD ... room, where the technologist operates the scanner and monitors your examination in direct visual contact and usually ...

  1. Computed Tomography (CT) -- Head

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    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... other in a ring, called a gantry. The computer workstation that processes the imaging information is located ...

  2. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... other in a ring, called a gantry. The computer workstation that processes the imaging information is located ...

  3. Computed Tomography (CT) -- Head

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    Full Text Available ... path. A special computer program processes this large volume of data to create two-dimensional cross-sectional ... many types of tissue as well as the lungs, bones, and blood vessels. CT examinations are fast ...

  4. Computed Tomography (CT) -- Sinuses

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    Full Text Available ... path. A special computer program processes this large volume of data to create two-dimensional cross-sectional ... many types of tissue as well as the lungs, bones, and blood vessels. CT examinations are fast ...

  5. In-Situ Observations of Longitudinal Compression Damage in Carbon-Epoxy Cross Ply Laminates Using Fast Synchrotron Radiation Computed Tomography

    Science.gov (United States)

    Bergan, Andrew C.; Garcea, Serafina C.

    2017-01-01

    The role of longitudinal compressive failure mechanisms in notched cross-ply laminates is studied experimentally with in-situ synchrotron radiation based computed tomography. Carbon/epoxy specimens loaded monotonically in uniaxial compression exhibited a quasi-stable failure process, which was captured with computed tomography scans recorded continuously with a temporal resolutions of 2.4 seconds and a spatial resolution of 1.1 microns per voxel. A detailed chronology of the initiation and propagation of longitudinal matrix splitting cracks, in-plane and out-of-plane kink bands, shear-driven fiber failure, delamination, and transverse matrix cracks is provided with a focus on kink bands as the dominant failure mechanism. An automatic segmentation procedure is developed to identify the boundary surfaces of a kink band. The segmentation procedure enables 3-dimensional visualization of the kink band and conveys the orientation, inclination, and spatial variation of the kink band. The kink band inclination and length are examined using the segmented data revealing tunneling and spatial variations not apparent from studying the 2-dimensional section data.

  6. Computed tomography:the details.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2007-07-01

    Computed Tomography (CT) is a well established technique, particularly in medical imaging, but also applied in Synthetic Aperture Radar (SAR) imaging. Basic CT imaging via back-projection is treated in many texts, but often with insufficient detail to appreciate subtleties such as the role of non-uniform sampling densities. Herein are given some details often neglected in many texts.

  7. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... risks? What are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside of ...

  8. Computed tomography of intramuscular myxoma

    Energy Technology Data Exchange (ETDEWEB)

    Ekelund, L.; Herrlin, K.; Rydholm, A.

    1982-11-01

    Computed tomography (CT) was performed in seven patients with intramuscular myxoma. All lesions were well demarcated, of homogeneous appearance and attenuation values ranging from 10 to 60 (HU). The tumor size, as estimated at CT, correlated well with the size of the surgical specimen, which is in contrast to the findings in some high grade malignant sarcomas.

  9. Computed tomography for dimensional metrology

    DEFF Research Database (Denmark)

    Kruth, J.P.; Bartscher, M.; Carmignato, S.

    2011-01-01

    The paper gives a survey of the upcoming use of X-ray computed tomography (CT) for dimensional quality control purposes: i.e. for traceable measurement of dimensions of technical (mechanical) components and for tolerance verification of such components. It describes the basic principles of CT met...

  10. Computed tomography in hepatic echinococcosis

    Energy Technology Data Exchange (ETDEWEB)

    Choliz, J.D.; Olaverri, F.J.L.; Casas, T.F.; Zubieta, S.O.

    1982-10-01

    Computed tomography (CT) was used to evaluate 50 cases of hydatid disease of the liver. It was definite in 49 cases and negative in one case. Pre- and postcontrast scans were performed. CT may reveal the exact location and extension of cysts and possible complications. However, a false-negative case was found in a hydatid cyst located in a fatty liver.

  11. Image quality and radiation dose of brain computed tomography in children: effects of decreasing tube voltage from 120 kVp to 80 kVp.

    Science.gov (United States)

    Park, Ji Eun; Choi, Young Hun; Cheon, Jung-Eun; Kim, Woo Sun; Kim, In-One; Cho, Hyun Suk; Ryu, Young Jin; Kim, Yu Jin

    2017-05-01

    Computed tomography (CT) has generated public concern associated with radiation exposure, especially for children. Lowering the tube voltage is one strategy to reduce radiation dose. To assess the image quality and radiation dose of non-enhanced brain CT scans acquired at 80 kilo-voltage peak (kVp) compared to those at 120 kVp in children. Thirty children who had undergone both 80- and 120-kVp non-enhanced brain CT were enrolled. For quantitative analysis, the mean attenuation of white and gray matter, attenuation difference, noise, signal-to-noise ratio, contrast-to-noise ratio and posterior fossa artifact index were measured. For qualitative analysis, noise, gray-white matter differentiation, artifact and overall image quality were scored. Radiation doses were evaluated by CT dose index, dose-length product and effective dose. The mean attenuations of gray and white matter and contrast-to-noise ratio were significantly increased at 80 kVp, while parameters related to image noise, i.e. noise, signal-to-noise ratio and posterior fossa artifact index were higher at 80 kVp than at 120 kVp. In qualitative analysis, 80-kVp images showed improved gray-white differentiation but more artifacts compared to 120-kVp images. Subjective image noise and overall image quality scores were similar between the two scans. Radiation dose parameters were significantly lower at 80 kVp than at 120 kVp. In pediatric non-enhanced brain CT scans, a decrease in tube voltage from 120 kVp to 80 kVp resulted in improved gray-white matter contrast, comparable image quality and decreased radiation dose.

  12. Image quality and radiation dose of brain computed tomography in children: effects of decreasing tube voltage from 120 kVp to 80 kVp

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Eun [Kyung Hee University Hospital, Department of Radiology, Graduate School, Seoul (Korea, Republic of); Choi, Young Hun [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Cheon, Jung-Eun; Kim, Woo Sun; Kim, In-One [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Cho, Hyun Suk; Ryu, Young Jin; Kim, Yu Jin [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of)

    2017-05-15

    Computed tomography (CT) has generated public concern associated with radiation exposure, especially for children. Lowering the tube voltage is one strategy to reduce radiation dose. To assess the image quality and radiation dose of non-enhanced brain CT scans acquired at 80 kilo-voltage peak (kVp) compared to those at 120 kVp in children. Thirty children who had undergone both 80- and 120-kVp non-enhanced brain CT were enrolled. For quantitative analysis, the mean attenuation of white and gray matter, attenuation difference, noise, signal-to-noise ratio, contrast-to-noise ratio and posterior fossa artifact index were measured. For qualitative analysis, noise, gray-white matter differentiation, artifact and overall image quality were scored. Radiation doses were evaluated by CT dose index, dose-length product and effective dose. The mean attenuations of gray and white matter and contrast-to-noise ratio were significantly increased at 80 kVp, while parameters related to image noise, i.e. noise, signal-to-noise ratio and posterior fossa artifact index were higher at 80 kVp than at 120 kVp. In qualitative analysis, 80-kVp images showed improved gray-white differentiation but more artifacts compared to 120-kVp images. Subjective image noise and overall image quality scores were similar between the two scans. Radiation dose parameters were significantly lower at 80 kVp than at 120 kVp. In pediatric non-enhanced brain CT scans, a decrease in tube voltage from 120 kVp to 80 kVp resulted in improved gray-white matter contrast, comparable image quality and decreased radiation dose. (orig.)

  13. Ultra-low dose dual-source high-pitch computed tomography of the paranasal sinus: diagnostic sensitivity and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Boris; Zangos, Stefan; Friedrichs, Ingke; Bauer, Ralf W.; Kerl, Matthias; Vogl, Thomas J.; Martin M Mack, Martin M. (Clinic of the Goethe Univ., Dept. of Diagnostic and Interventional Radiology, Frankfurt (Germany)), email: boris.schell@googlemail.com; Potente, Stefan (Clinic of the Goethe Univ., Dept. of Forensic Medicine, Frankfurt (Germany))

    2012-05-15

    Background: Today's gold standard for diagnostic imaging of inflammatory diseases of the paranasal sinus is computed tomography (CT). Purpose: To evaluate diagnostic sensitivity and radiation dose of an ultra-low dose dual-source CT technique. Material and Methods: Paranasal sinuses of 14 cadaveric heads were independently evaluated by two readers using a modern dual-source CT with lowest reasonable dosage in high-pitch mode (100 kV, 10 mAs, collimation 0.6 mm, pitch value 3.0). Additionally the head part of an anthropomorphic Alderson-Rando phantom was equipped with thermoluminescent detectors to measure radiation exposure to the eye lenses and thyroid gland. Results: Diagnostic accuracy regarding sinusoidal fluid, nasal septum deviation, and mucosal swelling was 100%. Mastoid fluid was detected in 76% and 92%, respectively. In the phantom study, average measured eye lens dosage was 0.64 mGy; radiation exposure of the thyroid gland was 0.085 mGy. Conclusion: Regarding evaluation of inflammatory diseases of the paranasal sinus this study indicates sufficient accuracy of the proposed CT protocol at a very low dosage level

  14. A low tube voltage technique reduces the radiation dose at retrospective ECG-gated cardiac computed tomography for anatomical and functional analyses.

    Science.gov (United States)

    Oda, Seitaro; Utsunomiya, Daisuke; Funama, Yoshinori; Awai, Kazuo; Katahira, Kazuhiro; Nakaura, Takeshi; Yanaga, Yumi; Namimoto, Tomohiro; Yamashita, Yasuyuki

    2011-08-01

    To investigate the effect of low-tube-voltage technique on a cardiac computed tomography (CT) for coronary arterial and cardiac functional analyses and radiation dose in slim patients. We enrolled 80 patients (52women, 28 men; mean age, 68.7 ± 8.9 years) undergoing retrospective electrocardiogram-gated 64-slice cardiac CT. Forty were subjected to the low (80-kV) and 40 to the standard (120-kV) tube-voltage protocol. Quantitative parameters of the coronary arteries (ie, CT attenuation, image noise, and the contrast-to-noise ratio [CNR]) were calculated, as were the effective radiation dose and the figure of merit (FOM). Each coronary artery segment was visually evaluated using a 5-point scale. Cardiac function calculated by using low-tube-voltage cardiac CT was compared with that on echocardiographs. CT attenuation and image noise were significantly higher at 80- than 120-kV (P tube-voltage cardiac CT and echocardiography for cardiac functional analyses. Low-tube-voltage cardiac CT significantly reduced the radiation dose by approximately 55% in slim patients while maintaining anatomical image quality and accuracy of cardiac functional analysis. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  15. Cone beam computed tomography in endodontic

    Energy Technology Data Exchange (ETDEWEB)

    Durack, Conor; Patel, Shanon, E-mail: conordurack1@hotmail.com [Unit of Endodontology, Department of Conservative Dentistry, King' s College London, London (United Kingdom)

    2012-07-01

    Cone beam computed tomography (CBCT) is a contemporary, radiological imaging system designed specifically for use on the maxillofacial skeleton. The system overcomes many of the limitations of conventional radiography by producing undistorted, three-dimensional images of the area under examination. These properties make this form of imaging particularly suitable for use in endodontic. The clinician can obtain an enhanced appreciation of the anatomy being assessed, leading to an improvement in the detection of endodontic disease and resulting in more effective treatment planning. In addition, CBCT operates with a significantly lower effective radiation dose when compared with conventional computed tomography (CT). The purpose of this paper is to review the current literature relating to the limitations and potential applications of CBCT in endodontic practice. (author)

  16. Effect of Tube Voltage (100 vs. 120 kVp) on Radiation Dose and Image Quality using Prospective Gating 320 Row Multi-detector Computed Tomography Angiography.

    Science.gov (United States)

    Khan, Atif N; Khosa, Faisal; Shuaib, Waqas; Nasir, Khurram; Blankstein, Ron; Clouse, Melvin

    2013-01-01

    The objective of the following study is to evaluate the effect of reducing tube voltage from 120 to 100 kVp using prospective gating 320 row multi-detector computed tomography angiography on image quality and reduction in radiation dose. A total of 78 sequential patients were scanned with prospective electrocardiogram gating. A total of 45 patients (Group 1) with mean body mass index (BMI) 29 ± 2 and heart rate (HR) 57 ± 7 beats per minute (BPM) were scanned at 120 kVp. 33 patients (Group 2) with mean BMI 23 ± 3 and HR 58 ± 6 bpm were scanned at 100 kVp. Effective dose was calculated using dose length product and factor (k = 0.014). Quantitative assessment of image quality was calculated by measuring signal to noise ratio (SNR) and contrast to noise ratio (CNR) in the left ventricle and left main coronary artery. Two experienced cardiac radiologists using a three-point ordinal scale assessed subjectively image quality. In Group 1, the median radiation dose was 5.31 mSv (95% confidence interval [CI]: 4.86-6.09) and for Group 2 (P = 0.009) the mean radiation dose was 3.71 mSv (95% CI: 2.76-4.87), representing 30% decrease in radiation dose. In multivariate analyses, adjusting for age, gender, HR, BMI, tube current and scan length, an absolute median reduction of 2.21 mSv (1.13-3.29 mSv) was noted in patients scanned with 100 kVp (P image quality (SNR and CNR) was not statistically significant between the groups. Subjective image quality was rated as good or excellent in 99% of coronary segments for both groups (P value was considered as non-significant). Our study suggests that radiation dose may be lowered from 120 to 100 kVp with preservation of image quality in patient's whose BMI is ≤27.

  17. Pediatric cranial computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, H.

    1984-01-01

    The introduction of CT in the investigation of intercranial pathology has revolutionized the approach to clinical neurological and neurosurgical practice. This book applies the advances of cranial CT to the pediatric patient. The test is divided into two sections. The first portion describes the practical methodology, anatomy and normal and abnormal CT scan appearance, including high or low density lesions, cystic lesions and ventricular or subarachnoid space dilation. The characteristic scans for various neurological diseases are presented and discussed. The author has given special attention to the CT diagnosis of congenital malformations and cerebral neoplasms. Partial Contents: Normal Computed Tomographic Anatomy/ High Density Lesions/Low Density Lesions/Cystic Lesions; Supratentorial/Cystic Lesions; Infratentorial/Increased Head Circumference/Increased Ventricular Size/Small Ventricular Size/Cranial Lesions/Spinal Lesions/CT Cisternography/Part II CT in Neonates/Congenital Craniocerebral Malformations/Hydrocephalus/Craniosynostosis/Head Trauma/Cerebrovascular Lesions/Intracranial Lesions/Seizure Disorders/Intracranial and Other Chronic Neurological Disorders.

  18. Cranial computed tomography in pediatrics

    Energy Technology Data Exchange (ETDEWEB)

    Boltshauser, E. (Zuerich Univ. (Switzerland). Kinderklinik)

    1984-01-01

    This paper deals mainly with methodical aspects (such as sedation, intravenous and intrathecal application of contrast media) and with common difficulties in interpretation of computed tomography images. The indications for cranial CT are discussed in respect to probable therapeutic consequences and expected diagnostic yield. In the view of the author CT is, as a rule, not required in assessing chronic headache, generalised epileptic convulsions, non-specific mental retardation and cerebral palsy.

  19. Computed Tomography in Forensic Medicine

    OpenAIRE

    Leth, Peter Mygind

    2015-01-01

    Modern diagnostic imagining techniques are gaining popularity in forensic medicine. Denmark has been involved in the development of this use of imaging techniques from the beginning. The Institute of Forensic Medicine at the University of Southern Denmark acquired a helical computed tomography (CT) scanner in 2006. This thesis presents our research on post-mortem CT (PMCT) and addresses the following research questions: 1. In how many cases can the cause of death be established by PMCT, and w...

  20. Evaluation of image quality and radiation dose using gold nanoparticles and other clinical contrast agents in dual-energy Computed Tomography (CT): CT abdomen phantom

    Science.gov (United States)

    Zukhi, J.; Yusob, D.; Tajuddin, A. A.; Vuanghao, L.; Zainon, R.

    2017-05-01

    The aim of this study was to evaluate the image quality and radiation dose using commercial gold nanoparticles and clinical contrast agents in dual-energy Computed Tomography (CT). Five polymethyl methacrylate (PMMA) tubes were used in this study, where four tubes were filled with different contrast agents (barium, iodine, gadolinium, and gold nanoparticles). The fifth tube was filled with water. Two optically stimulated luminescence dosimeters (OSLD) were placed in each tube to measure the radiation dose. The tubes were placed in a fabricated adult abdominal phantom of 32 cm in diameter using PMMA. The phantom was scanned using a DECT at low energy (80 kV) and high energy (140 kV) with different pitches (0.6 mm and 1.0 mm) and different slice thickness (3.0 mm and 5.0 mm). The tube current was applied automatically using automatic exposure control (AEC) and tube current modulation recommended by the manufacturer (CARE Dose 4D, Siemens, Germany). The contrast-to-noise ratio (CNR) of each contrast agent was analyzed using Weasis software. Gold nanoparticles has highest atomic number (Z = 79) than barium (Z = 56), iodine (Z = 53) and gadolinium (Z = 64). The CNR value of each contrast agent increases when the slice thickness increases. The radiation dose obtained from this study decreases when the pitch increases. The optimal imaging parameters for gold nanoparticles and other clinical contrast agents is obtained at pitch value of 1.0 mm and slice thickness of 5.0 mm. Low noise and low radiation dose obtained at these imaging parameters. The optimal imaging parameters obtained in this study can be applied in multiple contrast agents imaging.

  1. Automated tube voltage adaptation in head and neck computed tomography between 120 and 100 kV: effects on image quality and radiation dose.

    Science.gov (United States)

    May, Matthias S; Kramer, Manuel R; Eller, Achim; Wuest, Wolfgang; Scharf, Michael; Brand, Michael; Saake, Marc; Schmidt, Bernhard; Uder, Michael; Lell, Michael M

    2014-09-01

    Low tube voltage allows for computed tomography (CT) imaging with increased iodine contrast at reduced radiation dose. We sought to evaluate the image quality and potential dose reduction using a combination of attenuation based tube current modulation (TCM) and automated tube voltage adaptation (TVA) between 100 and 120 kV in CT of the head and neck. One hundred thirty consecutive patients with indication for head and neck CT were examined with a 128-slice system capable of TCM and TVA. Reference protocol was set at 120 kV. Tube voltage was reduced to 100 kV whenever proposed by automated analysis of the localizer. An additional small scan aligned to the jaw was performed at a fixed 120 kV setting. Image quality was assessed by two radiologists on a standardized Likert-scale and measurements of signal- (SNR) and contrast-to-noise ratio (CNR). Radiation dose was assessed as CTDIvol. Diagnostic image quality was excellent in both groups and did not differ significantly (p = 0.34). Image noise in the 100 kV data was increased and SNR decreased (17.8/9.6) in the jugular veins and the sternocleidomastoid muscle when compared to 120 kV (SNR 24.4/10.3), but not in fatty tissue and air. However, CNR did not differ statistically significant between 100 (23.5/14.4/9.4) and 120 kV data (24.2/15.3/8.6) while radiation dose was decreased by 7-8%. TVA between 100 and 120 kV in combination with TCM led to a radiation dose reduction compared to TCM alone, while keeping CNR constant though maintaining diagnostic image quality.

  2. Comparison of radiation doses imparted during 128-, 256-, 384-multislice CT-scanners and cone beam computed tomography for intra- and perioperative cochlear implant assessment.

    Science.gov (United States)

    Guberina, N; Dietrich, U; Arweiler-Harbeck, D; Forsting, M; Ringelstein, A

    2017-09-19

    To examine radiation-doses imparted during multislice (MSCT) and cone-beam computed-tomography (CBCT) for perioperative examination of cochlear-implant insertion. Radiation-doses were assessed during standardized petrous-bone CT-protocols at different MSCT ((I) single-source CT-scanner Somatom-Definition-AS+, (II) 2nd generation of dual-source CT-scanner Somatom-Definition-Flash, (III) 3rd generation of dual-source CT-scanner Somatom-Force and at the CBCT Ziehm-Vision-RFD3D ((IV) (a) RFD-3D (Standard-modifier), (b) RFD-3D (Low-dose-modifier)). Image quality was examined by two radiologists appraising electrode-array placement, quality-control of cochlear-implant surgery and complications based on real patients' examinations (n=78). In MSCT-setting following radiation-doses were assessed (CTDIw; DLP): (I) 21.5mGy; 216mGycm; (II) 19.7mGy; 195mGycm; (III) 12.7mGy; 127mGycm; in the CBCT setting radiation doses were distributed as follows: (IV) (a) 1.9mGy; 19.4mGycm; (b) 1.2mGy; 12.9mGycm. Overall, image quality was evaluated as good for both, MSCT- and CBCT-examinations, with a good interrater reliability (r=0.81). CBCT bears considerable dose-saving potential for the perioperative examination of cochlear-implant insertion while maintaining adequate image quality. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Minimized Radiation and Contrast Agent Exposure for Coronary Computed Tomography Angiography: First Clinical Experience on a Latest Generation 256-slice Scanner.

    Science.gov (United States)

    Benz, Dominik C; Gräni, Christoph; Hirt Moch, Beatrice; Mikulicic, Fran; Vontobel, Jan; Fuchs, Tobias A; Stehli, Julia; Clerc, Olivier F; Possner, Mathias; Pazhenkottil, Aju P; Gaemperli, Oliver; Buechel, Ronny R; Kaufmann, Philipp A

    2016-08-01

    The aim of the study was to evaluate the impact of the latest coronary computed tomography angiography (CCTA) techniques allowing a radiation- and contrast-sparing protocol on image quality in unselected patients referred for exclusion of suspected coronary artery disease (CAD). This prospective study was approved by the local ethics committee, and all patients provided written informed consent. Between March and June 2015, 89 consecutive patients (61% male; mean age 55 ± 11 years) referred for exclusion of CAD by 256-slice CCTA using prospective electrocardiogram triggering were included. Tube voltage (80-120 kVp), tube current (180-310 mA) as well contrast agent volume (25-45 mL) and flow rate (3.5-5 mL/s) were adapted to body mass index. Signal intensity was measured by placing a region of interest in the aortic root, the left main artery, and the proximal right coronary artery. Image noise was measured in the aortic root. Two independent blinded readers semi-quantitatively assessed the image quality regarding motion, noise, and contrast on a 4-point scale. Median contrast agent volume and median effective radiation dose were 35 mL (interquartile range, 30-40 mL) and 0.5 mSv (interquartile range, 0.4-0.6 mSv), respectively. Mean attenuation in the aortic root was 412 ± 89 Hounsfield units. Diagnostic image quality was obtained in 1050 of 1067 (98.4%) coronary segments and, on an intention-to-diagnosis basis, in 85 of 89 (95.5%) patients. Below a cut-off heart rate of 67 beats/min, only 1 of 974 (0.1%) coronary segments was nondiagnostic. A radiation- and contrast-sparing protocol for CCTA on a latest generation 256-slice computed tomography scanner yields diagnostic image quality in patients referred for CAD exclusion in daily clinical routine. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  4. Comparison of diagnostic performance between single- and multiphasic contrast-enhanced abdominopelvic computed tomography in patients admitted to the emergency department with abdominal pain: potential radiation dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Shin Hye; You, Je Sung; Choi, Jin-Young; Kim, Myeong-Jin; Chung, Yong Eun [Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, Seodaemun-gu, Seoul (Korea, Republic of); Song, Mi Kyong [Yonsei University, Biostatistics Collaboration Unit, College of Medicine, Seoul (Korea, Republic of)

    2015-04-01

    To evaluate feasibility of radiation dose reduction by optimal phase selection of computed tomography (CT) in patients who visited the emergency department (ED) for abdominal pain. We included 253 patients who visited the ED for abdominal pain. They underwent multiphasic CT including precontrast, late arterial phase (LAP), and hepatic venous phase (HVP). Three image sets (HVP, precontrast + HVP, and precontrast + LAP + HVP) were reviewed. Two reviewers determined the most appropriate diagnosis with five-point confidence scale. Diagnostic performances were compared among image sets by weighted-least-squares method or DeLong's method. Linear mixed model was used to assess changes of diagnostic confidence and radiation dose. There was no difference in diagnostic performance among three image sets, although diagnostic confidence level was significantly improved after review of triphasic images compared with both HVP images only or HVP with precontrast images (confidence scale, 4.64 ± 0.05, 4.66 ± 0.05, and 4.76 ± 0.04 in the order of the sets; overall P = 0.0008). Similar trends were observed in the subgroup analysis for diagnosis of pelvic inflammatory disease and cholecystitis. There is no difference between HVP-CT alone and multiphasic CT for the diagnosis of causes of abdominal pain in patients admitted to the ED without prior chronic disease or neoplasia. (orig.)

  5. Cone beam computed tomography in Endodontics - a review.

    Science.gov (United States)

    Patel, S; Durack, C; Abella, F; Shemesh, H; Roig, M; Lemberg, K

    2015-01-01

    Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on the applications and limitations of CBCT; (ii) make recommendations for the use of CBCT in Endodontics; (iii) highlight areas of further research of CBCT in Endodontics. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  6. Computed tomography of the chest with model-based iterative reconstruction using a radiation exposure similar to chest X-ray examination: preliminary observations

    Energy Technology Data Exchange (ETDEWEB)

    Neroladaki, Angeliki; Botsikas, Diomidis; Boudabbous, Sana; Becker, Christoph D.; Montet, Xavier [Geneva University Hospital, Department of Radiology, Geneva 4 (Switzerland)

    2013-02-15

    The purpose of this study was to assess the diagnostic image quality of ultra-low-dose chest computed tomography (ULD-CT) obtained with a radiation dose comparable to chest radiography and reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard dose diagnostic CT (SDD-CT) or low-dose diagnostic CT (LDD-CT) reconstructed with FBP alone. Unenhanced chest CT images of 42 patients acquired with ULD-CT were compared with images obtained with SDD-CT or LDD-CT in the same examination. Noise measurements and image quality, based on conspicuity of chest lesions on all CT data sets were assessed on a five-point scale. The radiation dose of ULD-CT was 0.16 {+-} 0.006 mSv compared with 11.2 {+-} 2.7 mSv for SDD-CT (P < 0.0001) and 2.7 {+-} 0.9 mSv for LDD-CT. Image quality of ULD-CT increased significantly when using MBIR compared with FBP or ASIR (P < 0.001). ULD-CT reconstructed with MBIR enabled to detect as many non-calcified pulmonary nodules as seen on SDD-CT or LDD-CT. However, image quality of ULD-CT was clearly inferior for characterisation of ground glass opacities or emphysema. Model-based iterative reconstruction allows detection of pulmonary nodules with ULD-CT with radiation exposure in the range of a posterior to anterior (PA) and lateral chest X-ray. (orig.)

  7. Computed tomography versus intravenous urography in diagnosis of acute flank pain from urolithiasis: a randomized study comparing imaging costs and radiation dose.

    Science.gov (United States)

    Thomson, J M; Glocer, J; Abbott, C; Maling, T M; Mark, S

    2001-08-01

    The equivalent sensitivity of non-contrast computed tomography (NCCT) and intravenous urography (IVU) in the diagnosis of suspected ureteric colic has been established. Approximately 50% of patients with suspected ureteric colic do not have a nephro-urological cause for pain. Because many such patients require further imaging studies, NCCT may obviate the need for these studies and, in so doing, be more cost effective and involve less overall radiation exposure. The present study compares the total imaging cost and radiation dose of NCCT versus IVU in the diagnosis of acute flank pain. Two hundred and twenty-four patients (157 men; mean age 45 years; age range 19-79 years) with suspected renal colic were randomized either to NCCT or IVU. The number of additional diagnostic imaging studies, cost (IVU A$136; CTU A$173), radiation exposure and imaging times were compared. Of 119 (53%) patients with renal obstruction, 105 had no nephro-urological causes of pain. For 21 (20%) of these patients an alternative diagnosis was made at the initial imaging, 10 of which were significant. Of 118 IVU patients, 28 (24%) required 32 additional imaging tests to reach a diagnosis, whereas seven of 106 (6%) NCCT patients required seven additional imaging studies. The average total diagnostic imaging cost for the NCCT group was A$181.94 and A$175.46 for the IVU group (P IVU) (P IVU) (P IVU, its advantages of faster diagnosis, the avoidance of additional diagnostic imaging tests and its ability to diagnose other causes makes it the study of choice for acute flank pain at Christchurch Hospital.

  8. Comparison of diagnostic performance between single- and multiphasic contrast-enhanced abdominopelvic computed tomography in patients admitted to the emergency department with abdominal pain: potential radiation dose reduction.

    Science.gov (United States)

    Hwang, Shin Hye; You, Je Sung; Song, Mi Kyong; Choi, Jin-Young; Kim, Myeong-Jin; Chung, Yong Eun

    2015-04-01

    To evaluate feasibility of radiation dose reduction by optimal phase selection of computed tomography (CT) in patients who visited the emergency department (ED) for abdominal pain. We included 253 patients who visited the ED for abdominal pain. They underwent multiphasic CT including precontrast, late arterial phase (LAP), and hepatic venous phase (HVP). Three image sets (HVP, precontrast + HVP, and precontrast + LAP + HVP) were reviewed. Two reviewers determined the most appropriate diagnosis with five-point confidence scale. Diagnostic performances were compared among image sets by weighted-least-squares method or DeLong's method. Linear mixed model was used to assess changes of diagnostic confidence and radiation dose. There was no difference in diagnostic performance among three image sets, although diagnostic confidence level was significantly improved after review of triphasic images compared with both HVP images only or HVP with precontrast images (confidence scale, 4.64 ± 0.05, 4.66 ± 0.05, and 4.76 ± 0.04 in the order of the sets; overall P = 0.0008). Similar trends were observed in the subgroup analysis for diagnosis of pelvic inflammatory disease and cholecystitis. There is no difference between HVP-CT alone and multiphasic CT for the diagnosis of causes of abdominal pain in patients admitted to the ED without prior chronic disease or neoplasia. • There was no difference in diagnostic performance of HVP CT and multiphasic CT. • The diagnostic confidence level was improved after review of the LAP images. • HVP CT can achieve diagnostic performance similar to that of multiphasic CT, while minimizing radiation.

  9. Industrial applications of computed tomography

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Carmignato, S.; Kruth, J. -P.

    2014-01-01

    The number of industrial applications of Computed Tomography(CT) is large and rapidly increasing. After a brief market overview, the paper gives a survey of state of the art and upcoming CT technologies, covering types of CT systems, scanning capabilities, and technological advances. The paper...... contains a survey of application examples from the manufacturing industry as well as from other industries, e.g., electrical and electronic devices, inhomogeneous materials, and from the food industry. Challenges as well as major national and international coordinated activities in the field of industrial...

  10. Optimizing radiation dose levels in prospectively electrocardiogram-triggered coronary computed tomography angiography using iterative reconstruction techniques: a phantom and patient study.

    Directory of Open Access Journals (Sweden)

    Yang Hou

    Full Text Available AIM: To investigate the potential of reducing the radiation dose in prospectively electrocardiogram-triggered coronary computed tomography angiography (CCTA while maintaining diagnostic image quality using an iterative reconstruction technique (IRT. METHODS AND MATERIALS: Prospectively-gated CCTA were first performed on a phantom using 256-slice multi-detector CT scanner at 120 kVp, with the tube output gradually reduced from 210 mAs (Group A to 125, 105, 84, and 63 mAs (Group B-E. All scans were reconstructed using filtered back projection (FBP algorithm and five IRT levels (L2-6, image quality (IQ assessment was performed. Based on the IQ assessment, Group D(120 kVp, 84 mAs reconstructed with L5 was found to provide IQ comparable to that of Group A with FBP. In the patient study, 21 patients underwent CCTA using 120 kV, 210 mAs with FBP reconstruction (Group 1 followed by 36 patients scanned with 120 kV, 84 mAs with IRT L5 (Group 2. Subjective and objective IQ and effective radiation dose were compared between two groups. RESULTS: In the phantom scans, there were no significant differences in image noise, contrast-to-noise ratio (CNR and modulation transfer function (MTF curves between Group A and the 84 mAs, 63 mAs groups (Groups D and E. Group D (120 kV, 84 mAs and L5 provided an optimum balance, producing equivalent image quality to Group A, at the lowest possible radiation dose. In the patient study, there were no significant difference in image noise, signal-to-noise ratio (SNR and CNR between Group 1 and Group 2 (p=0.71, 0.31, 0.5, respectively. The effective radiation dose in Group 2 was 1.21 ± 0.14 mSv compared to 3.20 ± 0.58 mSv (Group 1, reflecting dose savings of 62.5% (p<0.05. CONCLUSION: iterative reconstruction technique used in prospectively ECG-triggered 256-slice coronary CTA can provide radiation dose reductions of up to 62.5% with acceptable image quality.

  11. Effect of Tube Voltage (100 vs. 120 kVp on Radiation Dose and Image Quality using Prospective Gating 320 Row Multi-detector Computed Tomography Angiography

    Directory of Open Access Journals (Sweden)

    Atif N Khan

    2013-01-01

    Full Text Available Objectives : The objective of the following study is to evaluate the effect of reducing tube voltage from 120 to 100 kVp using prospective gating 320 row multi-detector computed tomography angiography on image quality and reduction in radiation dose. Materials and Methods : A total of 78 sequential patients were scanned with prospective electrocardiogram gating. A total of 45 patients (Group 1 with mean body mass index (BMI 29 ± 2 and heart rate (HR 57 ± 7 beats per minute (BPM were scanned at 120 kVp. 33 patients (Group 2 with mean BMI 23 ± 3 and HR 58 ± 6 bpm were scanned at 100 kVp. Effective dose was calculated using dose length product and factor (k = 0.014. Quantitative assessment of image quality was calculated by measuring signal to noise ratio (SNR and contrast to noise ratio (CNR in the left ventricle and left main coronary artery. Two experienced cardiac radiologists using a three-point ordinal scale assessed subjectively image quality. Results: In Group 1, the median radiation dose was 5.31 mSv (95% confidence interval [CI]: 4.86-6.09 and for Group 2 (P = 0.009 the mean radiation dose was 3.71 mSv (95% CI: 2.76-4.87, representing 30% decrease in radiation dose. In multivariate analyses, adjusting for age, gender, HR, BMI, tube current and scan length, an absolute median reduction of 2.21 mSv (1.13-3.29 mSv was noted in patients scanned with 100 kVp (P < 0.0001. The quantitative image quality (SNR and CNR was not statistically significant between the groups. Subjective image quality was rated as good or excellent in 99% of coronary segments for both groups (P value was considered as non-significant. Conclusion: Our study suggests that radiation dose may be lowered from 120 to 100 kVp with preservation of image quality in patient′s whose BMI is ≤27.

  12. Accuracy and Radiation Dose Reduction Using Low-Voltage Computed Tomography Coronary Artery Calcium Scoring With Tin Filtration

    NARCIS (Netherlands)

    Tesche, Christian; De Cecco, Carlo N.; Vliegenthart, Rozemarijn; Albrecht, Moritz Moritz H.; Varga-Szemes, Akos; Duguay, Taylor M.; Ebersberger, Ullrich; Bayer, Richard R.; Canstein, Christian; Schmidt, Bernhard; Allmendinger, Thomas; Litwin, Sheldon E.; Morris, Pamela B.; Flohr, Thomas G.; Hoffmann, Ellen; Schoepf, U. Joseph

    2017-01-01

    This study prospectively investigated the accuracy and radiation dose reduction of CT coronary artery calcium scoring (CACS) using a 100 kVp acquisition protocol with tin filtration (Sn100 kVp) compared with the standard 120 kVp acquisition protocol; 70 patients (59% men, 62.1 10.7 years) who

  13. Dose measurements on cone beam computed tomography for trilogy and truebeam STx for image-guided radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kwon; Ye, Sung Joon [Dept. of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul (Korea, Republic of); Kwon, Hyuck Jun; Sung, Won Mo [Interdisciplinary program in Radiation applied Life Science, College of Medicine, Seoul National University, Seoul (Korea, Republic of); Park, Jong Min [Dept. of Radiation Oncology, Seoul National University Hospital,Seoul (Korea, Republic of)

    2012-11-15

    The number of use of the intensity-modulated radiation therapy (IMRT) with the kV cone beam CT for the image-guided radiotherapy (IGRT) has increased. With the increased frequency in use of IGRT, the patient absorbed radiation dose during the treatment procedure has increased and become the major concern that there have been studies about these issue. The purpose of this study is to confirm the patient dose from the daily CBCT scan during the IGRT using the On-Board Imager(OBI) of Trilogy and Truebeam STx (Varian Medical Systems, CA, USA). These two linear accelerators are newly set up in SNUH that the patient dose from CBCT scan is needed to be verified before the start of IGRT. Daily CBCT scans can provide better patient localizing but increase the patient absorbed dose slightly. Considering the beneficial advantage on the localizing patient, CT dose during IGRT would be a reasonable cost.

  14. Excess of Radiation Burden for Young Testicular Cancer Patients using Automatic Exposure Control and Contrast Agent on Whole-body Computed Tomography Imaging.

    Science.gov (United States)

    Niiniviita, Hannele; Kulmala, Jarmo; Pölönen, Tuukka; Määttänen, Heli; Järvinen, Hannu; Salminen, Eeva

    2017-06-01

    The aim of the study was to assess patient dose from whole-body computed tomography (CT) in association with patient size, automatic exposure control (AEC) and intravenous (IV) contrast agent. Sixty-five testicular cancer patients (mean age 28 years) underwent altogether 279 whole-body CT scans from April 2000 to April 2011. The mean number of repeated examinations was 4.3. The GE LightSpeed 16 equipped with AEC and the Siemens Plus 4 CT scanners were used for imaging. Whole-body scans were performed with (216) and without (63) IV contrast. The ImPACT software was used to determine the effective and organ doses. Patient doses were independent (p agent caused significantly higher (13% Plus 4, 35% LightSpeed 16) exposure than non-contrast imaging (p agent and careful set-up of the AEC modulation parameters is recommended to avoid excessive radiation exposure on the whole-body CT imaging of young patients.

  15. Iterative reconstruction and individualized automatic tube current selection reduce radiation dose while maintaining image quality in 320-multidetector computed tomography coronary angiography.

    Science.gov (United States)

    Williams, M C; Weir, N W; Mirsadraee, S; Millar, F; Baird, A; Minns, F; Uren, N G; McKillop, G; Bull, R K; van Beek, E J R; Reid, J H; Newby, D E

    2013-11-01

    To assess the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualized automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA). In a single-centre cohort study, 942 patients underwent electrocardiogram-gated CTCA using a 320-multidetector CT system. Images from group 1 (n = 228) were reconstructed with a filtered back projection algorithm (Quantum Denoising Software, QDS+). Iterative reconstruction was used for group 2 (AIDR, n = 379) and group 3 (AIDR3D, n = 335). Tube current was selected based on body mass index (BMI) for groups 1 and 2, and selected automatically based on scout image attenuation for group 3. Subjective image quality was graded on a four-point scale (1 = excellent, 4 = non-diagnostic). There were no differences in age (p = 0.975), body mass index (p = 0.435), or heart rate (p = 0.746) between the groups. Image quality improved with iterative reconstruction and automatic tube current selection [1.3 (95% confidence intervals (CI): 1.2-1.4), 1.2 (1.1-1.2) and 1.1 (1-1.2) respectively; p image quality in CTCA. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Attenuation-based automatic kilovolt (kV)-selection in computed tomography of the chest: effects on radiation exposure and image quality.

    Science.gov (United States)

    Eller, Achim; Wuest, Wolfgang; Scharf, Michael; Brand, Michael; Achenbach, Stephan; Uder, Michael; Lell, Michael M

    2013-12-01

    To evaluate an automated attenuation-based kV-selection in computed tomography of the chest in respect to radiation dose and image quality, compared to a standard 120 kV protocol. 104 patients were examined using a 128-slice scanner. Fifty examinations (58 ± 15 years, study group) were performed using the automated adaption of tube potential (100-140 kV), based on the attenuation profile of the scout scan, 54 examinations (62 ± 14 years, control group) with fixed 120 kV. Estimated CT dose index (CTDI) of the software-proposed setting was compared with a 120 kV protocol. After the scan CTDI volume (CTDIvol) and dose length product (DLP) were recorded. Image quality was assessed by region of interest (ROI) measurements, subjective image quality by two observers with a 4-point scale (3--excellent, 0--not diagnostic). The algorithm selected 100 kV in 78% and 120 kV in 22%. Overall CTDIvol reduction was 26.6% (34% in 100 kV) overall DLP reduction was 22.8% (32.1% in 100 kV) (all pimage quality was excellent in both groups. The attenuation based kV-selection algorithm enables relevant dose reduction (~27%) in chest-CT while keeping image quality parameters at high levels. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Simultaneous in vivo synchrotron radiation computed tomography of regional ventilation and blood volume in rabbit lung using combined K-edge and temporal subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Suhonen, H [Department of Physical Sciences, University of Helsinki (Finland); Porra, L [Department of Physical Sciences, University of Helsinki (Finland); Bayat, S [Universite de Picardie Jules Verne, Faculte de Medecine, PERITOX (EA-INI RIS) and Cardiologie et Pneumo-Allerglogie Pediatriques, CHU Amiens (France); Sovijaervi, A R A [Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, Helsinki (Finland); Suortti, P [Department of Physical Sciences, University of Helsinki (Finland)

    2008-02-07

    In K-edge subtraction (KES) imaging with synchrotron radiation computed tomography (SRCT), two images are taken simultaneously using energies above and below the K-absorption edge of a contrast agent. A logarithmic difference image reveals the contrast agent concentration with good accuracy. Similarly, in temporal subtraction imaging (TSI) the reference image is taken before the introduction of the contrast agent. Quantitative comparisons of in vivo images of rabbit lung indicated that similar results for concentrations of iodine in blood vessels and xenon in airways are obtained by KES and TSI, but the level of noise and artifacts was higher in the latter. A linear fit showed that in the lung parenchyma {rho}{sub TSI} = (0.97 {+-} 0.03){rho}{sub KES} + (0.00 {+-} 0.05) for xenon and {rho}{sub TSI} = (1.21 {+-} 0.15){rho}{sub KES} + (0.0 {+-} 0.1) for iodine. For xenon the calculation of time constant of ventilation gave compatible values for both of the methods. The two methods are combined for the simultaneous determination of the xenon concentration (by KES) and the iodine concentration (by TSI) in lung imaging, which will allow simultaneous in vivo determination of ventilation and perfusion.

  18. 3D investigation on polystyrene colloidal crystals by floatage self-assembly with mixed solvent via synchrotron radiation x-ray phase-contrast computed tomography

    Science.gov (United States)

    Fu, Yanan; Xie, Honglan; Deng, Biao; Du, Guohao; Xiao, Tiqiao

    2017-06-01

    The floatage self-assembly method was introduced with mixed solvent as the medium of polystyrene sphere suspension to fabricate the colloidal crystal. The three dimensional (3D) void system of the colloidal crystal was noninvasively characterized by synchrotron radiation phase-contrast computed tomography, and the quantitative image analysis was implemented aiming to the polystyrene sphere colloidal crystal. Comparing with gravity sedimentation method, the three samples fabricated from floatage self-assembly with mixed solvents have the lowest porosity, and when ethylene glycol and water were mixed with ratio of 1:1, the lowest porosity of 27.49% could be achieved, that has been very close to the minimum porosity of ordered 3D monodisperse sphere array (26%). In single slices, the porosities and fractal dimension for the voids were calculated. The results showed that two factors would significantly influence the porosity of the whole colloidal crystal: the first deposited sphere layer's orderliness and the sedimentation speed of the spheres. The floatage self-assembly could induce a stable close-packing process, resulted from the powerful nucleation force-lateral capillary force coupled with the mixed solvent to regulate the floating upward speed for purpose of matching the assembly rate.

  19. Reducing radiation dose in the diagnosis of pulmonary embolism using adaptive statistical iterative reconstruction and lower tube potential in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kaul, David [Campus Virchow-Klinikum, Department of Radiation Oncology, Charite School of Medicine and University Hospital, Berlin (Germany); Charite School of Medicine and University Hospital, Department of Radiology, Berlin (Germany); Grupp, Ulrich; Kahn, Johannes; Wiener, Edzard; Hamm, Bernd; Streitparth, Florian [Charite School of Medicine and University Hospital, Department of Radiology, Berlin (Germany); Ghadjar, Pirus [Campus Virchow-Klinikum, Department of Radiation Oncology, Charite School of Medicine and University Hospital, Berlin (Germany)

    2014-11-15

    To assess the impact of ASIR (adaptive statistical iterative reconstruction) and lower tube potential on dose reduction and image quality in chest computed tomography angiographies (CTAs) of patients with pulmonary embolism. CT data from 44 patients with pulmonary embolism were acquired using different protocols - Group A: 120 kV, filtered back projection, n = 12; Group B: 120 kV, 40 % ASIR, n = 12; Group C: 100 kV, 40 % ASIR, n = 12 and Group D: 80 kV, 40 % ASIR, n = 8. Normalised effective dose was calculated; image quality was assessed quantitatively and qualitatively. Normalised effective dose in Group B was 33.8 % lower than in Group A (p = 0.014) and 54.4 % lower in Group C than in Group A (p < 0.001). Group A, B and C did not show significant differences in qualitative or quantitative analysis of image quality. Group D showed significantly higher noise levels in qualitative and quantitative analysis, significantly more artefacts and decreased overall diagnosability. Best results, considering dose reduction and image quality, were achieved in Group C. The combination of ASIR and lower tube potential is an option to reduce radiation without significant worsening of image quality in the diagnosis of pulmonary embolism. (orig.)

  20. Bone dynamics in the upward direction after a maxillary sinus floor elevation procedure: serial segmentation using synchrotron radiation micro-computed tomography.

    Science.gov (United States)

    Seo, Seung-Jun; Bark, Chung Wung; Lim, Jae-Hong; Kim, Yong-Gun

    2015-01-01

    Maxillary sinus floor augmentation has been shown to be the most predictable surgical technique for enhancing the bone volume in the posterior area of the maxilla. The purpose of this study was to analyze the serial slice image segmentation of newly formed bone and bone substitutes after sinus floor elevation using synchrotron radiation X-ray micro-computed tomography (SR-μCT). Bone biopsy specimens were collected after 6 months of sinus floor augmentation. From the six bone biopsy specimens, the cross-sectional images at every 8 μm along the apical direction from the inferior border using serial segmentation from three-dimensional reconstructed X-ray images were analyzed. The amount of new bone and bone substitutes were measured at each slicing image (300-430 images per specimen). The bone dynamics between the new bone and bone substitutes along the inferior-superior direction in humans after maxillary sinus floor elevation (MSFE) were analyzed using the whole sample region. Although these observations suggest that the specimens are structurally inhomogeneous, sinus floor elevation was confirmed to be a reliable surgical procedure for increasing the amount of bone. SR-μCT is highly effective for obtaining high-resolution images. An analysis of biological specimens using SR-μCT is quite reliable and this technique will be an important tool in the wide field of tissue engineering.

  1. Utility of the inspiratory phase in high-resolution computed tomography evaluations of pediatric patients with bronchiolitis obliterans after allogeneic bone marrow transplant: reducing patient radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Togni Filho, Paulo Henrique; Casagrande, Joao Luiz Marin; Lederman, Henrique Manoel, E-mail: paulotognifilho@gmail.com [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina. Dept. of Diagnostico por Imagem; Universidade de Sao Paulo (InRad/HC/FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Instituto de Radiologia

    2017-03-15

    Objective: To evaluate the utility of the inspiratory phase in high-resolution computed tomography (HRCT) of the chest for the diagnosis of post-bone marrow transplantation bronchiolitis obliterans. Materials and Methods: This was a retrospective, observational, cross-sectional study. We selected patients of either gender who underwent bone marrow transplantation and chest HRCT between March 1, 2002 and December 12, 2014. Ages ranged from 3 months to 20.7 years. We included all examinations in which the HRCT was performed appropriately. The examinations were read by two radiologists, one with extensive experience in pediatric radiology and another in the third year of residency, who determined the presence or absence of the following imaging features: air trapping, bronchiectasis, alveolar opacities, nodules, and atelectasis. Results: A total of 222 examinations were evaluated (mean, 5.4 ± 4.5 examinations per patient). The expiratory phase findings were comparable to those obtained in the inspiratory phase, except in one patient, in whom a small uncharacteristic nodule was identified only in the inspiratory phase. Air trapping was identified in a larger number of scans in the expiratory phase than in the inspiratory phase, as was atelectasis, although the difference was statistically significant only for air trapping. Conclusion: In children being evaluated for post-bone marrow transplantation bronchiolitis obliterans, the inspiratory phase can be excluded from the chest HRCT protocol, thus reducing by half the radiation exposure in this population. (author)

  2. Knowledge-based iterative model reconstruction: comparative image quality and radiation dose with a pediatric computed tomography phantom

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Young Jin; Choi, Young Hun [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Cheon, Jung-Eun; Kim, Woo Sun; Kim, In-One [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Ha, Seongmin [New York-Presbyterian Hospital and the Weill Cornell Medical College, Dalio Institute of Cardiovascular Imaging, New York, NY (United States)

    2016-03-15

    CT of pediatric phantoms can provide useful guidance to the optimization of knowledge-based iterative reconstruction CT. To compare radiation dose and image quality of CT images obtained at different radiation doses reconstructed with knowledge-based iterative reconstruction, hybrid iterative reconstruction and filtered back-projection. We scanned a 5-year anthropomorphic phantom at seven levels of radiation. We then reconstructed CT data with knowledge-based iterative reconstruction (iterative model reconstruction [IMR] levels 1, 2 and 3; Philips Healthcare, Andover, MA), hybrid iterative reconstruction (iDose{sup 4}, levels 3 and 7; Philips Healthcare, Andover, MA) and filtered back-projection. The noise, signal-to-noise ratio and contrast-to-noise ratio were calculated. We evaluated low-contrast resolutions and detectability by low-contrast targets and subjective and objective spatial resolutions by the line pairs and wire. With radiation at 100 peak kVp and 100 mAs (3.64 mSv), the relative doses ranged from 5% (0.19 mSv) to 150% (5.46 mSv). Lower noise and higher signal-to-noise, contrast-to-noise and objective spatial resolution were generally achieved in ascending order of filtered back-projection, iDose{sup 4} levels 3 and 7, and IMR levels 1, 2 and 3, at all radiation dose levels. Compared with filtered back-projection at 100% dose, similar noise levels were obtained on IMR level 2 images at 24% dose and iDose{sup 4} level 3 images at 50% dose, respectively. Regarding low-contrast resolution, low-contrast detectability and objective spatial resolution, IMR level 2 images at 24% dose showed comparable image quality with filtered back-projection at 100% dose. Subjective spatial resolution was not greatly affected by reconstruction algorithm. Reduced-dose IMR obtained at 0.92 mSv (24%) showed similar image quality to routine-dose filtered back-projection obtained at 3.64 mSv (100%), and half-dose iDose{sup 4} obtained at 1.81 mSv. (orig.)

  3. Knowledge-based iterative model reconstruction: comparative image quality and radiation dose with a pediatric computed tomography phantom.

    Science.gov (United States)

    Ryu, Young Jin; Choi, Young Hun; Cheon, Jung-Eun; Ha, Seongmin; Kim, Woo Sun; Kim, In-One

    2016-03-01

    CT of pediatric phantoms can provide useful guidance to the optimization of knowledge-based iterative reconstruction CT. To compare radiation dose and image quality of CT images obtained at different radiation doses reconstructed with knowledge-based iterative reconstruction, hybrid iterative reconstruction and filtered back-projection. We scanned a 5-year anthropomorphic phantom at seven levels of radiation. We then reconstructed CT data with knowledge-based iterative reconstruction (iterative model reconstruction [IMR] levels 1, 2 and 3; Philips Healthcare, Andover, MA), hybrid iterative reconstruction (iDose(4), levels 3 and 7; Philips Healthcare, Andover, MA) and filtered back-projection. The noise, signal-to-noise ratio and contrast-to-noise ratio were calculated. We evaluated low-contrast resolutions and detectability by low-contrast targets and subjective and objective spatial resolutions by the line pairs and wire. With radiation at 100 peak kVp and 100 mAs (3.64 mSv), the relative doses ranged from 5% (0.19 mSv) to 150% (5.46 mSv). Lower noise and higher signal-to-noise, contrast-to-noise and objective spatial resolution were generally achieved in ascending order of filtered back-projection, iDose(4) levels 3 and 7, and IMR levels 1, 2 and 3, at all radiation dose levels. Compared with filtered back-projection at 100% dose, similar noise levels were obtained on IMR level 2 images at 24% dose and iDose(4) level 3 images at 50% dose, respectively. Regarding low-contrast resolution, low-contrast detectability and objective spatial resolution, IMR level 2 images at 24% dose showed comparable image quality with filtered back-projection at 100% dose. Subjective spatial resolution was not greatly affected by reconstruction algorithm. Reduced-dose IMR obtained at 0.92 mSv (24%) showed similar image quality to routine-dose filtered back-projection obtained at 3.64 mSv (100%), and half-dose iDose(4) obtained at 1.81 mSv.

  4. Computed tomography scout views vs. conventional radiography in body-packers – Delineation of body-packs and radiation dose in a porcine model

    Energy Technology Data Exchange (ETDEWEB)

    Ziegeler, Edvard, E-mail: edvard.ziegeler@campus.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Grimm, Jochen M., E-mail: jochen.grimm@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Wirth, Stefan, E-mail: tefan.wirth@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Uhl, Michael, E-mail: michael.uhl@polizei.bayern.de [Bavarian State Criminal Police Office, Maillingerstrasse 15, 80636 Munich (Germany); Reiser, Maximilian F., E-mail: Maximilian.Reiser@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany); Scherr, Michael K., E-mail: Michael.Scherr@med.lmu.de [Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Nussbaumstraße 20, 80336 Munich (Germany)

    2012-12-15

    Objective: To compare abdominal computed tomography (CT) scout views with conventional radiography regarding radiation dose and delineation of drug packages in a porcine body-packer model. Materials and methods: Nine samples of illicit drugs packed in ovoid plastic containers were consecutively placed in the rectum of a 121.5 kg pig cadaver. Antero-posterior and lateral scout views were obtained at 120 kVp and 80 mA, 150 mA and 200 mA, respectively, using a 64-row MDCT. Scout views were compared with conventional abdominal antero-posterior radiographs (77 kV and 106 ± 13 mAs). Visibility of three body pack characteristics (wrapping, content, shape) was rated independently by two radiologists and summarized to a delineation score ranging from 0 to 9 with a score ≥6 representing sufficient delineation. Mean delineation scores were calculated for each conventional radiography and single plane scout view separately and for a combined rating of antero-posterior and lateral scout views. Results: Even the lowest single plane scout view delineation score (5.3 ± 2.0 for 80 mA lateral; 0.4 mSv; sensitivity = 44%) was significantly higher than for conventional radiographs (3.1 ± 2.5, p < 0.001; 2.4 ± 0.3 mSv; sensitivity = 11%). Combined reading of antero-posterior and lateral scout views 80 mA yielded sufficient delineation (6.2 ± 1.4; 0.8 mSv; sensitivity = 56%). Conclusions: All CT scout views showed significantly better delineation ratings and sensitivity than conventional radiographs. Scout views in two planes at 80 mA provided a sufficient level of delineation and a sensitivity five times higher than conventional radiography at less than one third of the radiation dose. In case of diagnostic insecurity, CT can be performed without additional logistical effort.

  5. Attenuation-based kV pair selection in dual source dual energy computed tomography angiography of the chest: impact on radiation dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Renapurkar, Rahul D.; Azok, Joseph; Lempel, Jason; Karim, Wadih; Graham, Ruffin [Thoracic Imaging, L10, Imaging Institute, Cleveland Clinic, Cleveland, OH (United States); Primak, Andrew [Siemens Medical Solutions, Malvern, PA (United States); Tandon, Yasmeen [Case Western Reserve University-Metro Health Medical Center, Department of Radiology, Cleveland, OH (United States); Bullen, Jennifer [Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH (United States); Dong, Frank [Section of Medical Physics, Cleveland Clinic, Cleveland, OH (United States)

    2017-08-15

    The purpose of this study was to evaluate the impact of attenuation-based kilovoltage (kV) pair selection in dual source dual energy (DSDE)-pulmonary embolism (PE) protocol examinations on radiation dose savings and image quality. A prospective study was carried out on 118 patients with suspected PE. In patients in whom attenuation-based kV pair selection selected the 80/140Sn kV pair, the pre-scan 100/140Sn CTDIvol (computed tomography dose index volume) values were compared with the pre-scan 80/140Sn CTDIvol values. Subjective and objective image quality parameters were assessed. Attenuation-based kV pair selection switched to the 80/140Sn kV pair (''switched'' cohort) in 63 out of 118 patients (53%). The mean 100/140Sn pre-scan CTDIvol was 8.8 mGy, while the mean 80/140Sn pre-scan CTDIvol was 7.5 mGy. The average estimated dose reduction for the ''switched'' cohort was 1.3 mGy (95% CI 1.2, 1.4; p < 0.001), representing a 15% reduction in dose. After adjusting for patient weight, mean attenuation was significantly higher in the ''switched'' vs. ''non-switched'' cohorts in all five pulmonary arteries and in all lobes on iodine maps. This study demonstrates that attenuation-based kV pair selection in DSDE examination is feasible and can offer radiation dose reduction without compromising image quality. (orig.)

  6. Noncontrast chest computed tomography immediately after transarterial chemoembolization in patients with hepatocellular carcinoma: Clinical benefits and effect of radiation reduction on image quality in low-dose scanning

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon-Il [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Seoul St. Mary' s Hospital, The Catholic University of Korea, Seoul (Korea, Republic of); Kim, Hyun Beom, E-mail: dockhb@naver.com [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Kim, Min Ju; Lee, Jong Seok [Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Koh, Young Whan; An, Sang Bu [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Ko, Heung-kyu [Department of Radiology, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of); Park, Joong-Won [Center for Liver Cancer, Research Institute and Hospital, National Cancer Center, Goyang-si (Korea, Republic of)

    2011-11-15

    Purpose: To evaluate the clinical benefits of noncontrast chest computed tomography (CT) immediately after transarterial chemoembolization in patients with hepatocellular carcinoma and to assess the effect of radiation reduction on image quality in low-dose scanning. Materials and methods: From June to October 2010, we performed standard-dose, noncontrast chest CTs immediately after transarterial chemoembolization in 160 patients and low-dose CTs in 88 patients. We reviewed the entire noncontrast chest CTs and follow-up CTs to reveal the clinical benefits of CT evaluation immediately after transarterial chemoembolization. Using two independent readers, we also retrospectively evaluated the radiation dose and image quality in terms of the image noise, contrast between the liver parenchyma and iodized oil and diagnostic acceptability for the evaluation of treatment response after transarterial chemoembolization. Results: In 5.2% of the patients, additional treatment was performed immediately after the interpretation of the noncontrast chest CT, and additional pulmonary lesions were found in 8.5% of the patients. The measured mean dose-length product for the low-dose scanning was 18.4% of that of the standard-dose scanning. The image noise was significantly higher with the low-dose scanning (p < 0.001). However, all of the low-dose CT scans were diagnostically acceptable, and the mean scores for the subjective assessments of the contrast and diagnostic acceptability showed no significant differences for either reader. Conclusion: A noncontrast chest CT immediately after transarterial chemoembolization has some clinical benefits for immediate decision making and detecting pulmonary lesions. Low-dose, noncontrast chest CTs immediately after transarterial chemoembolization consistently provide diagnostically acceptable images and information on treatment response in patients who have undergone transarterial chemoembolization.

  7. A comparison between radiation therapists and medical specialists in the use of kilovoltage cone-beam computed tomography scans for potential lung cancer radiotherapy target verification and adaptation

    Energy Technology Data Exchange (ETDEWEB)

    Watt, Sandie Carolyn, E-mail: sandie.watt@sswahs.gov.au [Liverpool and Macarthur Cancer Therapy Centres, NSW (Australia); University of Sydney, Sydney, NSW (Australia); Ingham Institute for Applied Medical Research, Liverpool, NSW (Australia); Vinod, Shalini K. [Liverpool and Macarthur Cancer Therapy Centres, NSW (Australia); Ingham Institute for Applied Medical Research, Liverpool, NSW (Australia); South Western Sydney Clinical School, The University of New South Wales, Liverpool, NSW (Australia); Department of Radiation Oncology, Prince of Wales Hospital, NSW (Australia); Dimigen, Marion [Department of Radiology, Liverpool Hospital, NSW (Australia); Department of Radiation Oncology, Prince of Wales Hospital, NSW (Australia); Descallar, Joseph [Ingham Institute for Applied Medical Research, Liverpool, NSW (Australia); South Western Sydney Clinical School, The University of New South Wales, Liverpool, NSW (Australia); Zogovic, Branimere [Department of Radiation Oncology, Prince of Wales Hospital, NSW (Australia); Atyeo, John [University of Sydney, Sydney, NSW (Australia); Wallis, Sian [University of Western Sydney, NSW (Australia); Holloway, Lois C. [Liverpool and Macarthur Cancer Therapy Centres, NSW (Australia); University of Sydney, Sydney, NSW (Australia); Institute of Medical Physics, University of Sydney, Sydney, NSW (Australia); Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia. (Australia); Ingham Institute for Applied Medical Research, Liverpool, NSW (Australia)

    2016-04-01

    Target volume matching using cone-beam computed tomography (CBCT) is the preferred treatment verification method for lung cancer in many centers. However, radiation therapists (RTs) are trained in bony matching and not soft tissue matching. The purpose of this study was to determine whether RTs were equivalent to radiation oncologists (ROs) and radiologists (RDs) in alignment of the treatment CBCT with the gross tumor volume (GTV) defined at planning and in delineating the GTV on the treatment CBCT, as may be necessary for adaptive radiotherapy. In this study, 10 RTs, 1 RO, and 1 RD performed a manual tumor alignment and correction of the planning GTV to a treatment CBCT to generate an isocenter correction distance for 15 patient data sets. Participants also contoured the GTV on the same data sets. The isocenter correction distance and the contoured GTVs from the RTs were compared with the RD and RO. The mean difference in isocenter correction distances was 0.40 cm between the RO and RD, 0.51 cm between the RTs, and RO and 0.42 cm between the RTs and RD. The 95% CIs were smaller than the equivalence limit of 0.5 cm, indicating that the RTs were equivalent to the RO and RD. For GTV delineation comparisons, the RTs were not found to be equivalent to the RD or RO. The alignment of the planning defined GTV and treatment CBCT using soft tissue matching by the RTs has been shown to be equivalent to those by the RO and RD. However, tumor delineation by the RTs on the treatment CBCT was not equivalent to that of the RO and RD. Thus, it may be appropriate for RTs to undertake soft tissue alignment based on CBCT; however, further investigation may be necessary before RTs undertake delineation for adaptive radiotherapy purposes.

  8. Adaptive Computed Tomography Imaging Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The present proposal describes the development of an adaptive Computed Tomography Imaging Spectrometer (CTIS), or "Snapshot" spectrometer which can "instantaneously"...

  9. Speeding up image reconstruction in computed tomography

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Computed tomography (CT) is a technique for imaging cross-sections of an object using X-ray measurements taken from different angles. In last decades a significant progress has happened there: today advanced algorithms allow fast image reconstruction and obtaining high-quality images even with missing or dirty data, modern detectors provide high resolution without increasing radiation dose, and high-performance multi-core computing devices are there to help us solving such tasks even faster. I will start with CT basics, then briefly present existing classes of reconstruction algorithms and their differences. After that I will proceed to employing distinctive architectural features of modern multi-core devices (CPUs and GPUs) and popular program interfaces (OpenMP, MPI, CUDA, OpenCL) for developing effective parallel realizations of image reconstruction algorithms. Decreasing full reconstruction time from long hours up to minutes or even seconds has a revolutionary impact in diagnostic medicine and industria...

  10. High-pitch computed tomography of the lung in pediatric patients. An intraindividual comparison of image quality and radiation dose to conventional 64-MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Tsiflikas, I.; Thomas, C.; Ketelsen, D.; Claussen, C.D.; Schaefer, J.F. [University Hospital of Tuebingen (Germany). Diagnostic and Interventional Radiology; Seitz, G.; Warmann, S. [University Hospital of Tuebingen (Germany). Pediatric Surgery

    2014-06-15

    Purpose: The aim of this study was to investigate frequencies of typical artifacts in low-dose pediatric lung examinations using high-pitch computed tomography (HPCT) compared to MDCT, and to estimate the effective radiation dose (E{sub eff}). Materials and Methods: Institutional review board approval for this retrospective study was obtained. 35 patients (17 boys, 18 girls; mean age 112 ± 69 months) were included and underwent MDCT and follow-up scan by HPCT or vice versa (mean follow-up time 87 days), using the same tube voltage and current. The total artifact score (0-8) was defined as the sum of artifacts arising from movement, breathing or pulsation of the heart or pulmonary vessels (0 - no; 1 - moderate; 2 - severe artifacts). E{sub eff} was estimated according to the European Guidelines on Quality Criteria for Multislice Computed Tomography. The Mann-Whitney U test was used to analyze differences between the patient groups. The Spearman's rank correlation coefficient was used for correlation of ordinal variables. Results: The scan time was significantly lower for HPCT compared to MDCT (0.72 ± 0.13 s vs. 3.65 ± 0.81s; p < 0.0001). In 28 of 35 (80 %) HPCT examinations no artifacts were visible, whereas in MDCT artifacts occurred in all examinations. The frequency of pulsation artifacts and breathing artifacts was higher in MDCT compared to HPCT (100% vs. 17% and 31% vs. 6%). The total artifact score significantly correlated with the patient's age in MDCT (r=-0.42; p=0.01), but not in HPCT (r=-0.32; p=0.07). The estimated E{sub eff} was significantly lower in HPCT than in MDCT (1.29±0.31 vs. 1.47±0.37 mSv; p < 0.0001). Conclusion: Our study indicates that the use of HPCT has advantages for pediatric lung imaging with a reduction of breathing and pulsation artifacts. Moreover, the estimated E{sub eff} was lower. In addition, examinations can be performed without sedation or breath-hold without losing image quality. (orig.)

  11. Detection of parathyroid adenomas using a monophasic dual-energy computed tomography acquisition: diagnostic performance and potential radiation dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Leiva-Salinas, Carlos; Flors, Lucia; Durst, Christopher R.; Hou, Qinghua; Mukherjee, Sugoto [University of Virginia, Department of Radiology, Division of Neuroradiology, Charlottesville, VA (United States); Patrie, James T. [University of Virginia, Department of Public Health Sciences, Charlottesville, VA (United States); Wintermark, Max [Stanford University, Department of Radiology, Palo Alto, CA (United States)

    2016-11-15

    The aims of the study were to compare the diagnostic performance of a combination of virtual non-contrast (VNC) images and arterial images obtained from a single-phase dual-energy CT (DECT) acquisition and standard non-contrast and arterial images from a biphasic protocol and to study the potential radiation dose reduction of the former approach. All DECT examinations performed for evaluation of parathyroid adenomas during a 13-month period were retrospectively reviewed. An initial single-energy unenhanced acquisition was followed by a dual-energy arterial phase acquisition. ''Virtual non-contrast images'' were generated from the dual-energy acquisition. Two independent and blinded radiologists evaluated three different sets of images during three reading sessions: single arterial phase, single-phase DECT (virtual non-contrast and arterial phase), and standard biphasic protocol (true non-contrast and arterial phase). The accuracy of interpretation in lateralizing an adenoma to the side of the neck and localizing it to a quadrant in the neck was evaluated. Sixty patients (mean age, 65.5 years; age range, 38-87 years) were included in the study. The lateralization and localization accuracy, sensitivity, and positive predicted value (PPV) and negative predicted value (NPV) of the different image datasets were comparable. The combination of VNC and arterial images was more specific than arterial images alone to lateralize a parathyroid lesion (OR = 1.93, p = 0.043). The use of the single-phase protocol resulted in a calculated radiation exposure reduction of 52.8 %. Virtual non-contrast and arterial images from a single DECT acquisition showed similar diagnostic accuracy than a biphasic protocol, providing a significant dose reduction. (orig.)

  12. Detection of parathyroid adenomas using a monophasic dual-energy computed tomography acquisition: diagnostic performance and potential radiation dose reduction.

    Science.gov (United States)

    Leiva-Salinas, Carlos; Flors, Lucia; Durst, Christopher R; Hou, Qinghua; Patrie, James T; Wintermark, Max; Mukherjee, Sugoto

    2016-11-01

    The aims of the study were to compare the diagnostic performance of a combination of virtual non-contrast (VNC) images and arterial images obtained from a single-phase dual-energy CT (DECT) acquisition and standard non-contrast and arterial images from a biphasic protocol and to study the potential radiation dose reduction of the former approach. All DECT examinations performed for evaluation of parathyroid adenomas during a 13-month period were retrospectively reviewed. An initial single-energy unenhanced acquisition was followed by a dual-energy arterial phase acquisition. "Virtual non-contrast images" were generated from the dual-energy acquisition. Two independent and blinded radiologists evaluated three different sets of images during three reading sessions: single arterial phase, single-phase DECT (virtual non-contrast and arterial phase), and standard biphasic protocol (true non-contrast and arterial phase). The accuracy of interpretation in lateralizing an adenoma to the side of the neck and localizing it to a quadrant in the neck was evaluated. Sixty patients (mean age, 65.5 years; age range, 38-87 years) were included in the study. The lateralization and localization accuracy, sensitivity, and positive predicted value (PPV) and negative predicted value (NPV) of the different image datasets were comparable. The combination of VNC and arterial images was more specific than arterial images alone to lateralize a parathyroid lesion (OR = 1.93, p = 0.043). The use of the single-phase protocol resulted in a calculated radiation exposure reduction of 52.8 %. Virtual non-contrast and arterial images from a single DECT acquisition showed similar diagnostic accuracy than a biphasic protocol, providing a significant dose reduction.

  13. Pair distribution function computed tomography.

    Science.gov (United States)

    Jacques, Simon D M; Di Michiel, Marco; Kimber, Simon A J; Yang, Xiaohao; Cernik, Robert J; Beale, Andrew M; Billinge, Simon J L

    2013-01-01

    An emerging theme of modern composites and devices is the coupling of nanostructural properties of materials with their targeted arrangement at the microscale. Of the imaging techniques developed that provide insight into such designer materials and devices, those based on diffraction are particularly useful. However, to date, these have been heavily restrictive, providing information only on materials that exhibit high crystallographic ordering. Here we describe a method that uses a combination of X-ray atomic pair distribution function analysis and computed tomography to overcome this limitation. It allows the structure of nanocrystalline and amorphous materials to be identified, quantified and mapped. We demonstrate the method with a phantom object and subsequently apply it to resolving, in situ, the physicochemical states of a heterogeneous catalyst system. The method may have potential impact across a range of disciplines from materials science, biomaterials, geology, environmental science, palaeontology and cultural heritage to health.

  14. Computed tomography of calcaneal fractures

    Energy Technology Data Exchange (ETDEWEB)

    Heger, L.; Wulff, K.; Seddiqi, M.S.A.

    1985-07-01

    Computed tomography (CT) of 25 fractured calcanei was performed to investigate the potential of CT in evaluating the pattern and biomechanics of these fractures. The characteristic findings of typical fractures are presented, including the number and type of principal fragments, size and dislocation of the sustentacular fragment, and involvement of the anterior and posterior facets of the subtalar joint. In 17 cases, the calcaneus consisted of four or more fragments. Furthermore, in 17 cases the sustentacular fragment included all or part of the posterior facet joint. In 18 of the 25 cases, the sustentacular fragment was displaced. It is concluded that well performed CT is an invaluable adjunct in understanding the fracture mechanism and in detecting pain-provoking impingement between the fibular malleolus and the tuberosity fragment.

  15. Diagnostic usefulness of computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K.; Tsugawa, R.; Yamakawa, Y. (Kanazawa Medical Univ., Uchinada, Ishikawa (Japan))

    1981-07-01

    Computed tomography (CT) has been used as a diagnostic technique in various urological diseases. Here demonstrated is a case of ureteral incontinence with double renal pelvis whose upper one has ectopic ureteral orifice. Also a case of ureteral stricture in transplanted kidney and three cases of uric acid calculi are demonstrated. CT provides accurate information in each diagnostic procedure. The use of CT in the diagnosis of urinary stones is estimated. CT number of 75 stones with single component shows specific distribution in relation to the component; ex. calcium stones: 900 - 1000, cystine: 700 - 800, struvite: 600 - 700, uric acid: 400 - 500. Structure and component of the stone is easily demonstrated by CT, especially about nonopaque calculi, whose image is positively displayed only by CT.

  16. Radiation Hardening of Computers

    Science.gov (United States)

    Nichols, D. K.; Smith, L. S.; Zoutendyk, J. A.; Giddings, A. E.; Hewlett, F. W.; Treece, R. K.

    1986-01-01

    Single-event upsets reduced by use of oversize transistors. Computers made less susceptible to ionizing radiation by replacing bipolar integrated circuits with properly designed, complementary metaloxide-semiconductor (CMOS) circuits. CMOS circuit chips made highly resistant to single-event upset (SEU), especially when certain feedback resistors are incorporated. Redesigned chips also consume less power than original chips.

  17. The impact of pediatric-specific dose modulation curves on radiation dose and image quality in head computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Joana; Paulo, Graciano [Instituto Politecnico de Coimbra, ESTESC, DMIR, Coimbra (Portugal); Foley, Shane; Rainford, Louise [University College Dublin, School of Medicine and Medical Science, Health Science Centre, Dublin 4 (Ireland); McEntee, Mark F. [The University of Sydney, Faculty of Health Sciences, Cumberland Campus, Sydney (Australia)

    2015-11-15

    The volume of CT examinations has increased with resultant increases in collective dose values over the last decade. To analyze the impact of the tube current and voltage modulation for dose values and image quality of pediatric head CT examinations. Head CT examinations were performed on anthropomorphic phantoms and four pediatric age categories before and after the introduction of dedicated pediatric curves for tube voltage and current modulation. Local diagnostic reference levels were calculated. Visual grading characteristic image quality evaluation was performed by four pediatric neuroradiologists and image noise comparisons were performed. Pediatric-specific modulation curves demonstrated a 49% decrease in mean radiation dose for phantom examinations. The local diagnostic reference levels (CTDIvol) for clinical examinations decreased by 52%, 41%, 46% and 40% for newborn, 5-, 10- and 15-year-old patients, respectively. Visual grading characteristic image quality was maintained for the majority of age categorizations (area under the curve = 0.5) and image noise measurements did not change (P = 0.693). Pediatric-specific dose modulation curves resulted in an overall mean dose reduction of 45% with no significant differences in subjective or objective image quality findings. (orig.)

  18. Low kilovoltage peak (kVp) with an adaptive statistical iterative reconstruction algorithm in computed tomography urography: evaluation of image quality and radiation dose.

    Science.gov (United States)

    Zhou, Zhiguo; Chen, Haixi; Wei, Wei; Zhou, Shanghui; Xu, Jingbo; Wang, Xifu; Wang, Qingguo; Zhang, Guixiang; Zhang, Zhuoli; Zheng, Linfeng

    2016-01-01

    The purpose of this study was to evaluate the image quality and radiation dose in computed tomography urography (CTU) images acquired with a low kilovoltage peak (kVp) in combination with an adaptive statistical iterative reconstruction (ASiR) algorithm. A total of 45 subjects (18 women, 27 men) who underwent CTU with kV assist software for automatic selection of the optimal kVp were included and divided into two groups (A and B) based on the kVp and image reconstruction algorithm: group A consisted of patients who underwent CTU with a 80 or 100 kVp and whose images were reconstructed with the 50% ASiR algorithm (n=32); group B consisted of patients who underwent CTU with a 120 kVp and whose images were reconstructed with the filtered back projection (FBP) algorithm (n=13). The images were separately reconstructed with volume rendering (VR) and maximum intensity projection (MIP). Finally, the image quality was evaluated using an image score, CT attenuation, image noise, the contrast-to-noise ratio (CNR) of the renal pelvis-to-abdominal visceral fat and the signal-to-noise ratio (SNR) of the renal pelvis. The radiation dose was assessed using volume CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED). For groups A and B, the subjective image scores for the VR reconstruction images were 3.9±0.4 and 3.8±0.4, respectively, while those for the MIP reconstruction images were 3.8±0.4 and 3.6±0.6, respectively. No significant difference was found (p>0.05) between the two groups' image scores for either the VR or MIP reconstruction images. Additionally, the inter-reviewer image scores did not significantly differ (p>0.05). The mean attenuation of the bilateral renal pelvis in group A was significantly higher than that in group B (271.4±57.6 vs. 221.8±35.3 HU, preconstruction exhibit sufficient image quality and facilitate up to a 44% radiation dose reduction.

  19. Computed tomography evolution of multicystic encephalomalacia.

    Science.gov (United States)

    Smith, R R; Savolaine, E R

    1986-07-01

    A case of multicystic encephalomalacia is presented, demonstrating postischemic maldevelopment in the cerebrum on serial computed tomography scans. The developmental features of multicystic encephalomalacia are discussed, as well as migration abnormalities such as encephaloclastic porencephaly and agenetic porencephaly. Representative computed tomography scans of porencephaly are included.

  20. Multi-detector computed tomography radiation doses in the follow-up of paediatric neurosurgery patients in KwaZulu-Natal: A dosimetric audit

    Directory of Open Access Journals (Sweden)

    Christopher T. Sikwila

    2014-04-01

    Full Text Available Background: Multi-detector computed tomography (MDCT is the preferred modality for follow-up of paediatric neurosurgery patients. Serial imaging, however, has the disadvantage of an ionising radiation burden, which may be mitigated using the ‘as low as reasonably achievable’ (ALARA principle. Objectives: The primary objectives were to determine the radiation dose exposure in paediatric patients subjected to MDCT imaging following neurosurgery and to compare these values with references in current literature. Our secondary objective was to assess the relationship between radiation dose and clinical scenario.Method: Retrospective descriptive data were collected from all paediatric postsurgical patients (n = 169 between the ages of 0 and 12 years who had their first followed-up scan in the year 2010 and were followed up for six months or less. Dose-length product (DLP and current-time product were collected from the picture archiving and communication system. Demographic data including radiology reports were collected from the hospital information system. The effective doses (ED were calculated from the corresponding DLP using age-adjusted conversion factors. For purposes of comparison with other studies, median dosimetric values were calculated and the children were grouped into three age ranges, namely younger than 3 years, 3–7 years and 8–12 years old.Results: The highest median radiation doses were noted in patients being followed-up for intracranial abscesses (1183 mGy cm in the 8–12 year age group, most of whom were female. The lowest radiation doses were for intracranial shunt follow-ups (447 mGy cm. Median values for DLP, ED and current-time product (mAs were comparable to reference doses in all three age groups. However, our study showed a much broader distribution of values with higher upper limits relative to reference values. Indications for follow-up included shunts (n = 110; 65%, intracranial abscess (n = 31; 18%, subdural

  1. Comparative of radiation dose and image quality of Conventional Multislice Computed Tomography (MSCT), Cone-Beam CT (CBCT) and periapical radiography in dental imaging

    OpenAIRE

    Nasrollah Jabbari; Seyyed Reza Mousavi; Kamal Firoozi

    2016-01-01

    Background and Aims: With the increasing use of CT (Computed Tomoghraphy) scans in dentistry especially in the implantology, there may be significant increases in the radiation exposure and its risk. During the last year’s ConeBeam Computed Tomoghraphy (CBCT) has been introduced as an imaging modality for dentistry. The aim of this review article was to present comprehensive information have been published, regarding the  radiation dose and image quality of Conventional Multis...

  2. [Computed tomography and cranial paleoanthropology].

    Science.gov (United States)

    Cabanis, Emmanuel Alain; Badawi-Fayad, Jackie; Iba-Zizen, Marie-Thérèse; Istoc, Adrian; de Lumley, Henry; de Lumley, Marie-Antoinette; Coppens, Yves

    2007-06-01

    Since its invention in 1972, computed tomography (C.T.) has significantly evolved. With the advent of multi-slice detectors (500 times more sensitive than conventional radiography) and high-powered computer programs, medical applications have also improved. CT is now contributing to paleoanthropological research. Its non-destructive nature is the biggest advantage for studying fossil skulls. The second advantage is the possibility of image analysis, storage, and transmission. Potential disadvantages include the possible loss of files and the need to keep up with rapid technological advances. Our experience since the late 1970s, and a recent PhD thesis, led us to describe routine applications of this method. The main contributions of CT to cranial paleoanthropology are five-fold: --Numerical anatomy with rapid acquisition and high spatial resolution (helicoidal and multidetector CT) offering digital storage and stereolithography (3D printing). --Numerical biometry (2D and 3D) can be used to create "normograms" such as the 3D craniofacial reference model used in maxillofacial surgery. --Numerical analysis offers thorough characterization of the specimen and its state of conservation and/or restoration. --From "surrealism" to virtual imaging, anatomical structures can be reconstructed, providing access to hidden or dangerous zones. --The time dimension (4D imaging) confers movement and the possibility for endoscopic simulation and internal navigation (see Iconography). New technical developments will focus on data processing and networking. It remains our duty to deal respectfully with human fossils.

  3. Imaging performance of phase-contrast breast computed tomography with synchrotron radiation and a CdTe photon-counting detector.

    Science.gov (United States)

    Sarno, A; Mettivier, G; Golosio, B; Oliva, P; Spandre, G; Di Lillo, F; Fedon, C; Longo, R; Russo, P

    2016-05-01

    Within the SYRMA-CT collaboration based at the ELETTRA synchrotron radiation (SR) facility the authors investigated the imaging performance of the phase-contrast computed tomography (CT) system dedicated to monochromatic in vivo 3D imaging of the female breast, for breast cancer diagnosis. Test objects were imaged at 38keV using monochromatic SR and a high-resolution CdTe photon-counting detector. Signal and noise performance were evaluated using modulation transfer function (MTF) and noise power spectrum. The analysis was performed on the images obtained with the application of a phase retrieval algorithm as well as on those obtained without phase retrieval. The contrast to noise ratio (CNR) and the capability of detecting test microcalcification clusters and soft masses were investigated. For a voxel size of (60μm)(3), images without phase retrieval showed higher spatial resolution (6.7mm(-1) at 10% MTF) than corresponding images with phase retrieval (2.5mm(-1)). Phase retrieval produced a reduction of the noise level and an increase of the CNR by more than one order of magnitude, compared to raw phase-contrast images. Microcalcifications with a diameter down to 130μm could be detected in both types of images. The investigation on test objects indicates that breast CT with a monochromatic SR source is technically feasible in terms of spatial resolution, image noise and contrast, for in vivo 3D imaging with a dose comparable to that of two-view mammography. Images obtained with the phase retrieval algorithm showed the best performance in the trade-off between spatial resolution and image noise. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. {sup 18}F-Choline Positron Emission Tomography/Computed Tomography and Multiparametric Magnetic Resonance Imaging for the Detection of Early Local Recurrence of Prostate Cancer Initially Treated by Radiation Therapy: Comparison With Systematic 3-Dimensional Transperineal Mapping Biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Kanoun, Salim, E-mail: Salim.kanoun@gmail.com [Department of Nuclear Medicine, Centre Georges-François Leclerc, Dijon (France); LE2I UMR6306, Centre national de la recherche scientifique, Arts et Métiers, Université Bourgogne Franche-Comté, Dijon (France); MRI Unit, Centre Hospitalier Régional Universitaire, Hôpital François Mitterrand, Dijon (France); Walker, Paul [LE2I UMR6306, Centre national de la recherche scientifique, Arts et Métiers, Université Bourgogne Franche-Comté, Dijon (France); MRI Unit, Centre Hospitalier Régional Universitaire, Hôpital François Mitterrand, Dijon (France); Vrigneaud, Jean-Marc; Depardon, Edouard [Department of Nuclear Medicine, Centre Georges-François Leclerc, Dijon (France); Barbier, Vincent [Department of Urology, Centre Hospitalier Régional Universitaire, Hôpital François Mitterrand, Dijon (France); Humbert, Olivier [Department of Nuclear Medicine, Centre Georges-François Leclerc, Dijon (France); Moulin, Morgan [Department of Urology, Centre Hospitalier Régional Universitaire, Hôpital François Mitterrand, Dijon (France); and others

    2017-04-01

    Purpose: To compare the diagnostic performance of {sup 18}F-fluorocholine positron emission tomography/computed tomography (FCH-PET/CT), multiparametric prostate magnetic resonance imaging (mpMRI), and a combination of both techniques for the detection of local recurrence of prostate cancer initially treated by radiation therapy. Methods and Materials: This was a retrospective, single-institution study of 32 patients with suspected prostate cancer recurrence who underwent both FCH-PET/CT and 3T mpMRI within 3 months of one another for the detection of recurrence. All included patients had to be cleared for metastatic recurrence. The reference procedure was systematic 3-dimensional (3D)-transperineal prostate biopsy for the final assessment of local recurrence. Both imaging modalities were analyzed by 2 experienced readers blinded to clinical data. The analysis was made per-patient and per-segment using a 4-segment model. Results: The median prostate-specific antigen value at the time of imaging was 2.92 ng/mL. The mean prostate-specific antigen doubling time was 14 months. Of the 32 patients, 31 had a positive 3D-transperineal mapping biopsy for a local relapse. On a patient-based analysis, the detection rate was 71% (22 of 31) for mpMRI and 74% (23 of 31) for FCH-PET/CT. On a segment-based analysis, the sensitivity and specificity were, respectively, 32% and 87% for mpMRI, 34% and 87% for FCH-PET/CT, and 43% and 83% for the combined analysis of both techniques. Accuracy was 64%, 65%, and 66%, respectively. The interobserver agreement was κ = 0.92 for FCH-PET/CT and κ = 0.74 for mpMRI. Conclusions: Both mpMRI and FCH-PET/CT show limited sensitivity but good specificity for the detection of local cancer recurrence after radiation therapy, when compared with 3D-transperineal mapping biopsy. Prostate biopsy still seems to be mandatory to diagnose local relapse and select patients who could benefit from local salvage therapy.

  5. System Matrix Analysis for Computed Tomography Imaging.

    Directory of Open Access Journals (Sweden)

    Liubov Flores

    Full Text Available In practical applications of computed tomography imaging (CT, it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data.

  6. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

    2013-01-01

    on the market today based on different perfusion algorithms. However, there is no consensus on which protocol and algorithm to use for specific organs. In this article, the authors give an introduction to CT perfusion in abdominal imaging introducing technical aspects for calculation of perfusion parameters......Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...... table position. Advances in reconstruction algorithms make it possible to reduce the radiation dose for each examination to acceptable levels. Regarding abdominal imaging, CT perfusion is still considered a research tool, but several studies have proven it as a reliable non-invasive technique...

  7. Intraoperative 3D Computed Tomography: Spine Surgery.

    Science.gov (United States)

    Adamczak, Stephanie E; Bova, Frank J; Hoh, Daniel J

    2017-10-01

    Spinal instrumentation often involves placing implants without direct visualization of their trajectory or proximity to adjacent neurovascular structures. Two-dimensional fluoroscopy is commonly used to navigate implant placement, but with the advent of computed tomography, followed by the invention of a mobile scanner with an open gantry, three-dimensional (3D) navigation is now widely used. This article critically appraises the available literature to assess the influence of 3D navigation on radiation exposure, accuracy of instrumentation, operative time, and patient outcomes. Also explored is the latest technological advance in 3D neuronavigation: the manufacturing of, via 3D printers, patient-specific templates that direct implant placement. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Advanced proton imaging in computed tomography

    CERN Document Server

    Mattiazzo, S; Giubilato, P; Pantano, D; Pozzobon, N; Snoeys, W; Wyss, J

    2015-01-01

    In recent years the use of hadrons for cancer radiation treatment has grown in importance, and many facilities are currently operational or under construction worldwide. To fully exploit the therapeutic advantages offered by hadron therapy, precise body imaging for accurate beam delivery is decisive. Proton computed tomography (pCT) scanners, currently in their R&D phase, provide the ultimate 3D imaging for hadrons treatment guidance. A key component of a pCT scanner is the detector used to track the protons, which has great impact on the scanner performances and ultimately limits its maximum speed. In this article, a novel proton-tracking detector was presented that would have higher scanning speed, better spatial resolution and lower material budget with respect to present state-of-the-art detectors, leading to enhanced performances. This advancement in performances is achieved by employing the very latest development in monolithic active pixel detectors (to build high granularity, low material budget, ...

  9. Intra-abdominal fat: Comparison of computed tomography fat ...

    African Journals Online (AJOL)

    Background: Intra-abdominal fat is an important factor in determining the metabolic syndrome/insulin resistance, and thus the risk of diabetes and ischaemic heart disease. Computed Tomography (CT) fat segmentation represents a defined method of quantifying intra-abdominal fat, with attendant radiation risks.

  10. Automatic Substitute Computed Tomography Generation and Contouring for Magnetic Resonance Imaging (MRI)-Alone External Beam Radiation Therapy From Standard MRI Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, Jason A., E-mail: jason.dowling@csiro.au [CSIRO Australian e-Health Research Centre, Herston, Queensland (Australia); University of Newcastle, Callaghan, New South Wales (Australia); Sun, Jidi [University of Newcastle, Callaghan, New South Wales (Australia); Pichler, Peter [Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Rivest-Hénault, David; Ghose, Soumya [CSIRO Australian e-Health Research Centre, Herston, Queensland (Australia); Richardson, Haylea [Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Wratten, Chris; Martin, Jarad [University of Newcastle, Callaghan, New South Wales (Australia); Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Arm, Jameen [Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Best, Leah [Department of Radiology, Hunter New England Health, New Lambton, New South Wales (Australia); Chandra, Shekhar S. [School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Queensland (Australia); Fripp, Jurgen [CSIRO Australian e-Health Research Centre, Herston, Queensland (Australia); Menk, Frederick W. [University of Newcastle, Callaghan, New South Wales (Australia); Greer, Peter B. [University of Newcastle, Callaghan, New South Wales (Australia); Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia)

    2015-12-01

    Purpose: To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. Patients and Methods: A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1.6 mm 3-dimensional isotropic T2w SPACE [Sampling Perfection with Application optimized Contrasts using different flip angle Evolution] sequence) was acquired. Three additional small field of view scans were acquired: T2w, T2*w, and T1w flip angle 80° for gold fiducials. Patients received a routine planning CT scan. Manual contouring of the prostate, rectum, bladder, and bones was performed independently on the CT and MR scans. Three experienced observers contoured each organ on MRI, allowing interobserver quantification. To generate a training database, each patient CT scan was coregistered to their whole-pelvis T2w using symmetric rigid registration and structure-guided deformable registration. A new multi-atlas local weighted voting method was used to generate automatic contours and sCT results. Results: The mean error in Hounsfield units between the sCT and corresponding patient CT (within the body contour) was 0.6 ± 14.7 (mean ± 1 SD), with a mean absolute error of 40.5 ± 8.2 Hounsfield units. Automatic contouring results were very close to the expert interobserver level (Dice similarity coefficient): prostate 0.80 ± 0.08, bladder 0.86 ± 0.12, rectum 0.84 ± 0.06, bones 0.91 ± 0.03, and body 1.00 ± 0.003. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same dose prescription was found to be 0.3% ± 0.8%. The 3-dimensional γ pass rate was 1.00 ± 0.00 (2 mm/2%). Conclusions: The MR-Sim setup and automatic s

  11. Computed tomography of odontogenic myxoma

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald-Jankowski, D.S. E-mail: d.macdon@interchange.ubc.ca; Yeung, R.W.K.; Li, T.; Lee, K.M

    2004-03-01

    AIM: The aim of this study was to determine the computed tomography (CT) presentation of odontogenic myxoma (OM) in a Chinese population and to compare them with those observed on the accompanying conventional radiographs (CR). MATERIALS AND METHODS: The files of the Department of Oral and Maxillofacial Surgery of the University of Hong Kong between 1989 and 2000 were reviewed for myxoma cases. RESULTS: Ten cases of OM were found of which eight had been investigated by CT. The formatted hard copy was found in seven cases, four in the maxilla and three in the mandible. Most of the OMs had a round shape but one was fusiform. CT was more likely to display a cortex and its perforation. All OMs had perforated cortices on CT with soft tissue appearing outside the bony contour in two cases. Contrast enhancement was apparent in six cases. Both CR and CT displayed septae, but the latter method revealed that most septae were situated at the periphery, presenting as 'sunray' type spicules in one case. Tooth displacement and root resorption were more reliably observed on CR. CONCLUSION: The likelihood of perforation and pattern of septa of OM is better displayed by CT. CR should also allow a better assessment of the degree of definition of the lesion's margins with adjacent normal bone. Therefore, both CT and CR should be used in an investigation of an OM.

  12. Thermoluminescent dosimetry in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lara C, A.; Rivera M, T. [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Av. Legaria 694, Col. Irrigacion, 11500 Ciudad de Mexico (Mexico); Osorio V, M. [ISSSTE, Centro Medico Nacional 20 de Noviembre, Felix Cuevas 540, Col. del Valle, 03100 Ciudad de Mexico (Mexico); Hernandez O, O., E-mail: armando_lara_cam@yahoo.com.mx [Hospital General de Mexico, Dr. Balmis 148, Col. Doctores, 06726 Ciudad de Mexico (Mexico)

    2016-10-15

    In this work we studied the dosimetry performed on CT scan in two different equipment, SOMATOM and Phillips, with 16 and 64 slice respectively. We used 51 pellets of lithium fluoride doped with magnesium and titanium (LiF: Mg, Ti) also knows as TLD-100 due to its physical properties and its easy of use, in this study, first analysis a batch of 56 pellets, but only 53 pellets were optimal for this study, cesium-137 was used as source irradiation, then proceeded to calibrate the batch with X-rays source, measuring the corresponding dose in a Farmers ionization chamber, then, we obtained a calibration curve, and we used as reference to calculation of the applied dose, finally designing ergonomic mesh, were it was deposited a TLD 100, placed in a regions of interest were made to each scan type. Once characterized our material proceeded to testing in 30 patients, which were irradiated with X-ray tube, whose operation was performed at 80, 120 kV with a current of 100, 300 and 400 m A according to scanning protocol. Overall we measured dose of 5 mGy to 53 mGy, these measurements reflect significant dose to can induced cancer, due previous reports published, that doses greater than 20 mGy there is a risk of developing cancer in the long term, but in practice when it assigned a medical diagnosis, there are no dose limits due to benefits patients, however, IAEA publish recommendations that allow us to carry out optimum handling of ionizing radiation, among these is the quality control of the tomography equipment that helps greatly reduce patient dose. (Author)

  13. Development of a proton Computed Tomography Detector System

    CERN Document Server

    Naimuddin, Md; Blazey, G; Boi, S; Dyshkant, A; Erdelyi, B; Hedin, D; Johnson, E; Krider, J; Rukalin, V; Uzunyan, S A; Zutshi, V; Fordt, R; Sellberg, G; Rauch, J E; Roman, M; Rubinov, P; Wilson, P

    2015-01-01

    Computer tomography is one of the most promising new methods to image abnormal tissues inside the human body. Tomography is also used to position the patient accurately before radiation therapy. Hadron therapy for treating cancer has become one of the most advantageous and safe options. In order to fully utilize the advantages of hadron therapy, there is a necessity of performing radiography with hadrons as well. In this paper we present the development of a proton computed tomography system. Our second-generation proton tomography system consists of two upstream and two downstream trackers made up of fibers as active material and a range detector consisting of plastic scintillators. We present details of the detector system, readout electronics, and data acquisition system as well as the commissioning of the entire system. We also present preliminary results from the test beam of the range detector.

  14. Development of a proton Computed Tomography Detector System

    Energy Technology Data Exchange (ETDEWEB)

    Naimuddin, Md. [Delhi U.; Coutrakon, G. [Northern Illinois U.; Blazey, G. [Northern Illinois U.; Boi, S. [Northern Illinois U.; Dyshkant, A. [Northern Illinois U.; Erdelyi, B. [Northern Illinois U.; Hedin, D. [Northern Illinois U.; Johnson, E. [Northern Illinois U.; Krider, J. [Northern Illinois U.; Rukalin, V. [Northern Illinois U.; Uzunyan, S. A. [Northern Illinois U.; Zutshi, V. [Northern Illinois U.; Fordt, R. [Fermilab; Sellberg, G. [Fermilab; Rauch, J. E. [Fermilab; Roman, M. [Fermilab; Rubinov, P. [Fermilab; Wilson, P. [Fermilab

    2016-02-04

    Computer tomography is one of the most promising new methods to image abnormal tissues inside the human body. Tomography is also used to position the patient accurately before radiation therapy. Hadron therapy for treating cancer has become one of the most advantegeous and safe options. In order to fully utilize the advantages of hadron therapy, there is a necessity of performing radiography with hadrons as well. In this paper we present the development of a proton computed tomography system. Our second-generation proton tomography system consists of two upstream and two downstream trackers made up of fibers as active material and a range detector consisting of plastic scintillators. We present details of the detector system, readout electronics, and data acquisition system as well as the commissioning of the entire system. We also present preliminary results from the test beam of the range detector.

  15. Extended Field Intensity Modulated Radiation Therapy With Concomitant Boost for Lymph Node–Positive Cervical Cancer: Analysis of Regional Control and Recurrence Patterns in the Positron Emission Tomography/Computed Tomography Era

    Energy Technology Data Exchange (ETDEWEB)

    Vargo, John A.; Kim, Hayeon; Choi, Serah [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Sukumvanich, Paniti; Olawaiye, Alexander B.; Kelley, Joseph L.; Edwards, Robert P.; Comerci, John T. [Department of Gynecologic Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States); Beriwal, Sushil, E-mail: beriwals@upmc.edu [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania (United States)

    2014-12-01

    Purpose: Positron emission tomography/computed tomography (PET/CT) is commonly used for nodal staging in locally advanced cervical cancer; however the false negative rate for para-aortic disease are 20% to 25% in PET-positive pelvic nodal disease. Unless surgically staged, pelvis-only treatment may undertreat para-aortic disease. We have treated patients with PET-positive nodes with extended field intensity modulated radiation therapy (IMRT) to address the para-aortic region prophylactically with concomitant boost to involved nodes. The purpose of this study was to assess regional control rates and recurrence patterns. Methods and Materials: Sixty-one patients with cervical cancer (stage IBI-IVA) diagnosed from 2003 to 2012 with PET-avid pelvic nodes treated with extended field IMRT (45 Gy in 25 fractions with concomitant boost to involved nodes to a median of 55 Gy in 25 fractions) with concurrent cisplatin and brachytherapy were retrospectively analyzed. The nodal location was pelvis-only in 41 patients (67%) and pelvis + para-aortic in 20 patients (33%). There were a total of 179 nodes, with a median number of positive nodes of 2 (range, 1-16 nodes) per patient and a median nodal size of 1.8 cm (range, 0.7-4.5 cm). Response was assessed by PET/CT at 12 to 16 weeks. Results: Complete clinical and imaging response at the first follow-up visit was seen in 77% of patients. At a mean follow-up time of 29 months (range, 3-116 months), 8 patients experienced recurrence. The sites of persistent/recurrent disease were as follows: cervix 10 (16.3%), regional nodes 3 (4.9%), and distant 14 (23%). The rate of para-aortic failure in patients with pelvic-only nodes was 2.5%. There were no significant differences in recurrence patterns by the number/location of nodes, largest node size, or maximum node standardized uptake value. The rate of late grade 3+ adverse events was 4%. Conclusions: Extended field IMRT was well tolerated and resulted in low regional recurrence

  16. Quantitative computed tomography evaluation of pulmonary disease

    DEFF Research Database (Denmark)

    McEvoy, Fintan; Buelund, Lene Elisabeth; Strathe, Anders Bjerring

    2009-01-01

    Objective assessment of pulmonary disease from computed tomography (CT) examinations is desirable but difficult. When such assessments can be made, it is important that they are related to some part of the pathophysiologic process present....

  17. Validation of High-Risk Computed Tomography Features for Detection of Local Recurrence After Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Peulen, Heike [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands); Mantel, Frederick [Department of Radiation Oncology, University of Wuerzburg, Wuerzburg (Germany); Department of Radiation Oncology, University Hospital Zurich, Zurich (Switzerland); Guckenberger, Matthias [Department of Radiation Oncology, University of Wuerzburg, Wuerzburg (Germany); Belderbos, José [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands); Werner-Wasik, Maria [Department of Radiation Oncology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Hope, Andrew; Giuliani, Meredith [Department of Radiation Oncology University of Toronto and Princess Margaret Cancer Center, Toronto, Ontario (Canada); Grills, Inga [Department of Radiation Oncology Beaumont Hospital, Royal Oak, Michigan (United States); Sonke, Jan-Jakob, E-mail: j.sonke@nki.nl [Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam (Netherlands)

    2016-09-01

    Purpose: Fibrotic changes after stereotactic body radiation therapy (SBRT) for stage I non-small cell lung cancer (NSCLC) are difficult to distinguish from local recurrences (LR), hampering proper patient selection for salvage therapy. This study validates previously reported high-risk computed tomography (CT) features (HRFs) for detection of LR in an independent patient cohort. Methods and Materials: From a multicenter database, 13 patients with biopsy-proven LR were matched 1:2 to 26 non-LR control patients based on dose, planning target volume (PTV), follow-up time, and lung lobe. Tested HRFs were enlarging opacity, sequential enlarging opacity, enlarging opacity after 12 months, bulging margin, linear margin disappearance, loss of air bronchogram, and craniocaudal growth. Additionally, 2 new features were analyzed: the occurrence of new unilateral pleural effusion, and growth based on relative volume, assessed by manual delineation. Results: All HRFs were significantly associated with LR except for loss of air bronchogram. The best performing HRFs were bulging margin, linear margin disappearance, and craniocaudal growth. Receiver operating characteristic analysis of the number of HRFs to detect LR had an area under the curve (AUC) of 0.97 (95% confidence interval [CI] 0.9-1.0), which was identical to the performance described in the original report. The best compromise (closest to 100% sensitivity and specificity) was found at ≥4 HRFs, with a sensitivity of 92% and a specificity of 85%. A model consisting of only 2 HRFs, bulging margin and craniocaudal growth, resulted in a sensitivity of 85% and a specificity of 100%, with an AUC of 0.96 (95% CI 0.9-1.0) (HRFs ≥2). Pleural effusion and relative growth did not significantly improve the model. Conclusion: We successfully validated CT-based HRFs for detection of LR after SBRT for early-stage NSCLC. As an alternative to number of HRFs, we propose a simplified model with the combination of the 2 best HRFs

  18. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... tomography, more commonly known as a CT or CAT scan, is a diagnostic medical test that, like ... imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  19. Examination of weld defects by computed tomography

    Directory of Open Access Journals (Sweden)

    M. Jovanović

    2012-04-01

    Full Text Available Defects in metal arc gas (MAG welds made in S235JR low carbon steel of 6 mm thickness were examined. A sample containing lack of fusion (LOF and pores was examined by computed tomography – CT. The computed tomography examination was performed in order to define LOF size and position as well as dimensions and distribution of accompanying pores in the weld metal.

  20. Computed tomography in abnormalities of the hip

    Energy Technology Data Exchange (ETDEWEB)

    Visser, J.D.; Jonkers, A.; Klasen, H.J. (Rijksuniversiteit Groningen (Netherlands). Academisch Ziekenhuis); Hillen, B. (Rijksuniversiteit Groningen (Netherlands). Lab. voor Anatomie en Embryologie)

    1982-06-26

    The value of computed tomography in the assessment of abnormalities of the hip is demonstrated with the aid of an anatomical preparation and in patients with, respectively, congenital dislocation of a hip, dislocation of the hip in spina bifida, an acetabular fracture and a Ewing tumour. The anteversion of the acetabulum and femur and the instability index of the hip joint can be measured by means of computed tomography.

  1. Image quality in coronary computed tomography angiography

    DEFF Research Database (Denmark)

    Precht, Helle; Gerke, Oke; Thygesen, Jesper

    2018-01-01

    Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT...... angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality...... was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDIvol resulted in 10.3 mGy, 7.4 mGy, and 4.6 m...

  2. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... radiation children may receive from a CT scan. One of the best ways of limiting radiation exposure ... or pediatrician and the radiologist will decide which type of examination is best for your child. top ...

  3. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Anesthesia Safety Children and Radiation Safety Images ...

  4. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... be required to wear a lead apron to prevent radiation exposure. The radiation dose directly outside of ... child will stay in the department for a recovery period and will be given instructions on any ...

  5. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... ray examinations. X-rays are a form of radiation, like light or radio waves that can be ... conventional x-ray exam, a small burst of radiation passes through the body, recording an image on ...

  6. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... or thyroid problems. Any of these conditions may influence the decision on whether contrast material will be ... to wear a lead apron to prevent radiation exposure. The radiation dose directly outside of the CT ...

  7. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... scanner. top of page How does the procedure work? In many ways, CT scanning is like other ... radiation children may receive from a CT scan. One of the best ways of limiting radiation exposure ...

  8. Positron emission tomography/computed tomography scanning for ...

    African Journals Online (AJOL)

    Background: Although the site of nosocomial sepsis in the critically ill ventilated patient is usually identifiable, it may remain occult, despite numerous investigations. The rapid results and precise anatomical location of the septic source using positron emission tomography (PET) scanning, in combination with computed ...

  9. Computed Tomography evaluation of maxillofacial injuries

    Directory of Open Access Journals (Sweden)

    V Natraj Prasad

    2017-01-01

    Full Text Available Background & Objectives: The maxillofacial region, a complex anatomical structure, can be evaluated by conventional (plain films, Tomography, Multidetector Computed Tomography, Three-Dimensional Computed Tomography, Orthopantomogram and Magnetic Resonance Imaging. The study was conducted with objective of describing various forms of maxillofacial injuries, imaging features of different types of maxillofacial fractures and the advantage of using Three- Dimensional Computed Tomography reconstructed image. Materials & Methods: A hospital based cross-sectional study was conducted among 50 patients during April 2014 to September 2016 using Toshiba Aquilion Prime 160 slice Multi Detector Computed Tomography scanner.Results: The maxillofacial fractures were significantly higher in male population (88% than female population (12 %. Road traffic accidents were the most common cause of injury others being physical assault and fall from height. It was most common in 31-40 years (26% and 21-30 (24% years age group. Maxillary sinus was the commonest fracture (36% followed by nasal bone and zygomatic bone (30%, mandible and orbital bones (28%. Soft tissue swelling was the commonest associated finding. Three dimensional images (3 D compared to the axial scans missed some fractures. However, the extension of the complex fracture lines and degree of displacement were more accurately assessed. Complex fractures found were Le fort (6% and naso-orbito-ethmoid (4% fractures.Conclusion: The proper evaluation of complex anatomy of the facial bones requires Multidetector Computed Tomography which offers excellent spatial resolution enabling multiplanar reformations and three dimensional reconstructions for enhanced diagnostic accuracy and surgical planning.

  10. Possible Radiation-Induced Damage to the Molecular Structure of Wooden Artifacts Due to Micro-Computed Tomography, Handheld X-Ray Fluorescence, and X-Ray Photoelectron Spectroscopic Techniques

    Directory of Open Access Journals (Sweden)

    Madalena Kozachuk

    2016-05-01

    Full Text Available This study was undertaken to ascertain whether radiation produced by X-ray photoelectron spectroscopy (XPS, micro-computed tomography (μCT and/or portable handheld X-ray fluorescence (XRF equipment might damage wood artifacts during analysis. Changes at the molecular level were monitored by Fourier transform infrared (FTIR analysis. No significant changes in FTIR spectra were observed as a result of μCT or handheld XRF analysis. No substantial changes in the collected FTIR spectra were observed when XPS analytical times on the order of minutes were used. However, XPS analysis collected over tens of hours did produce significant changes in the FTIR spectra.

  11. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... able to see, hear and speak with your child at all times. A parent may be allowed in the room but will be required to wear a lead apron to prevent radiation exposure. The radiation ... child. Some imaging facilities may use general anesthesia or ...

  12. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... which rotates around the patient. The computer that processes the imaging information and monitor are located in ... follows a spiral path. A special computer program processes this series of pictures, or slices of the ...

  13. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... images. These images can be viewed on a computer monitor, printed on film or transferred to a ... a gantry, which rotates around the patient. The computer that processes the imaging information and monitor are ...

  14. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... your child. top of page Additional Information and Resources The Alliance for Radiation Safety in Pediatric Imaging's " ... A child being prepared for a CT scan. View full size with caption Pediatric Content Some imaging ...

  15. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... or pediatrician and the radiologist will decide which type of examination is best for your child. top of page Additional Information and Resources The Alliance for Radiation Safety in Pediatric Imaging's "Image Gently" Campaign top ...

  16. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... The risk of serious allergic reaction to contrast materials that contain iodine is rare in children, and almost always mild, and radiology departments are well-equipped to deal with them. Radiation is ...

  17. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... CT of the chest is used to evaluate: complications from infections such as pneumonia a tumor that ... radiation dose. There always is a risk of complications from general anesthesia or sedation. Every measure will ...

  18. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... x-ray exam, a small burst of radiation passes through the body, recording an image on photographic ... of CT scan, the machine may make several passes. Patients may be asked to hold their breath ...

  19. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... or thyroid problems. Any of these conditions may influence the decision on whether contrast material will be ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams ...

  20. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... as a CT or CAT scan, is a diagnostic medical test that, like traditional x-rays, produces ... lowest radiation dose that will provide the needed diagnostic information. The benefit of an accurate diagnosis far ...

  1. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... a form of radiation, like light or radio waves that can be directed at the body. Different ... pictures, or slices of the body, to create two-dimensional cross-sectional images, which are then displayed ...

  2. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... best for your child. top of page Additional Information and Resources The Alliance for Radiation Safety in ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  3. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... a gown. You may be instructed to withhold food or drink beforehand, especially if sedation or anesthesia ... accurate diagnosis far outweighs the risk. See the Safety page for more information about radiation dose. There ...

  4. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... CT scans that are not clearly needed. Another strategy is to consider other tests, such as MRI ... sensitive to radiation, they should have a CT study only if it is essential for making a ...

  5. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... the technologist determines that the images are of high enough quality for the radiologist to read. top ... to obtain CT images. It is known that high levels of radiation may cause cancer. However, CT ...

  6. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... benefits vs. risks? Benefits Using a multidetector CT unit to examine children is faster than the older ... CT scanning may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a ...

  7. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... scanner. top of page How does the procedure work? In many ways, CT scanning is like other ... accurate diagnosis far outweighs the risk. See the Safety page for more information about radiation dose. There ...

  8. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... can be performed if you have an implanted medical device of any kind, unlike MRI. CT imaging provides ... accurate diagnosis far outweighs the risk. See the Safety page for more information about radiation dose. There ...

  9. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... X-rays are a form of radiation, like light or radio waves that can be directed at ... with medication, if necessary. If your child becomes light-headed or experiences difficulty breathing, you should notify ...

  10. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the ... eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body after ...

  11. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... radiologist to read. top of page What will my child experience during and after the procedure? CT ... sensitive to radiation, they should have a CT study only if it is essential for making a ...

  12. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ... by Please note RadiologyInfo.org is not a medical facility. Please contact your physician with specific medical ...

  13. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... over time. Follow-up examinations are sometimes the best way to see if treatment is working or ... receive from a CT scan. One of the best ways of limiting radiation exposure is to avoid ...

  14. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT ... note RadiologyInfo.org is not a medical facility. Please contact your physician with specific medical ...

  15. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... sensitive to radiation, they should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary. top of page What are ...

  16. Children's (Pediatric) CT (Computed Tomography)

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    Full Text Available ... back, but sometimes in other positions. Straps and pillows may be used to help the patient maintain ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  17. Children's (Pediatric) CT (Computed Tomography)

    Science.gov (United States)

    ... back, but sometimes in other positions. Straps and pillows may be used to help the patient maintain ... may eliminate the need for exploratory surgery and surgical biopsy. No radiation remains in a patient's body ...

  18. Dedicated breast computed tomography: Basic aspects

    Energy Technology Data Exchange (ETDEWEB)

    Sarno, Antonio; Mettivier, Giovanni, E-mail: mettivier@na.infn.it; Russo, Paolo [Dipartimento di Fisica, Università di Napoli Federico II, Via Cintia, Napoli I-80126, Italy and INFN Sezione di Napoli, Napoli I-80126 (Italy)

    2015-06-15

    X-ray mammography of the compressed breast is well recognized as the “gold standard” for early detection of breast cancer, but its performance is not ideal. One limitation of screening mammography is tissue superposition, particularly for dense breasts. Since 2001, several research groups in the USA and in the European Union have developed computed tomography (CT) systems with digital detector technology dedicated to x-ray imaging of the uncompressed breast (breast CT or BCT) for breast cancer screening and diagnosis. This CT technology—tracing back to initial studies in the 1970s—allows some of the limitations of mammography to be overcome, keeping the levels of radiation dose to the radiosensitive breast glandular tissue similar to that of two-view mammography for the same breast size and composition. This paper presents an evaluation of the research efforts carried out in the invention, development, and improvement of BCT with dedicated scanners with state-of-the-art technology, including initial steps toward commercialization, after more than a decade of R and D in the laboratory and/or in the clinic. The intended focus here is on the technological/engineering aspects of BCT and on outlining advantages and limitations as reported in the related literature. Prospects for future research in this field are discussed.

  19. A Detector for Proton Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blazey, G.; et al.

    2013-12-06

    Radiation therapy is a widely recognized treatment for cancer. Energetic protons have distinct features that set them apart from photons and make them desirable for cancer therapy as well as medical imaging. The clinical interest in heavy ion therapy is due to the fact that ions deposit almost all of their energy in a sharp peak – the Bragg peak- at the very end of their path. Proton beams can be used to precisely localize a tumor and deliver an exact dose to the tumor with small doses to the surrounding tissue. Proton computed tomography (pCT) provides direct information on the location on the target tumor, and avoids position uncertainty caused by treatment planning based on imaging with X-ray CT. The pCT project goal is to measure and reconstruct the proton relative stopping power distribution directly in situ. To ensure the full advantage of cancer treatment with 200 MeV proton beams, pCT must be realized.

  20. Optical tomography for measuring dose distribution in radiation therapy

    Directory of Open Access Journals (Sweden)

    Kauppinen Matti

    2014-01-01

    Full Text Available The dosimetry is used to verify the dose magnitude with artificial samples (phantoms before giving the planned radiation therapy to the patient. Typically, dose distribution is measured only in a single point or on a two-dimensional matrix plane. New techniques of radiation therapy ensure more detailed planning of radiation dose distribution which will lead to the need of measuring the radiation dose distribution three-dimensionally. The gel dosimetry is used to indicate and determine the ionizing radiation three-dimensionally. The radiation causes changes in chemical properties of the gel. The radiation dose distribution is defined by measuring the chemical changes. A conventional method is the magnetic resonance imaging and a new possibility is optical computed tomography (optical-CT. The optical-CT is much cheaper and more practical than magnetic resonance imaging. In this project, an optical-CT based method device was built by aiming at low material costs and a simple realization. The constructed device applies the charge coupled device camera and fluorescent lamp technologies. The test results show that the opacity level of the radiated gel can be measured accurately enough. The imaging accuracy is restricted by the optical distortion, e. g. vignetting, of the lenses, the distortion of a fluorescent lamp as the light source and a noisy measuring environment.

  1. Measuring radiation dose in computed tomography using elliptic phantom and free-in-air, and evaluating iterative metal artifact reduction algorithm

    Science.gov (United States)

    Morgan, Ashraf

    The need for an accurate and reliable way for measuring patient dose in multi-row detector computed tomography (MDCT) has increased significantly. This research was focusing on the possibility of measuring CT dose in air to estimate Computed Tomography Dose Index (CTDI) for routine quality control purposes. New elliptic CTDI phantom that better represent human geometry was manufactured for investigating the effect of the subject shape on measured CTDI. Monte Carlo simulation was utilized in order to determine the dose distribution in comparison to the traditional cylindrical CTDI phantom. This research also investigated the effect of Siemens health care newly developed iMAR (iterative metal artifact reduction) algorithm, arthroplasty phantom was designed and manufactured that purpose. The design of new phantoms was part of the research as they mimic the human geometry more than the existing CTDI phantom. The standard CTDI phantom is a right cylinder that does not adequately represent the geometry of the majority of the patient population. Any dose reduction algorithm that is used during patient scan will not be utilized when scanning the CTDI phantom, so a better-designed phantom will allow the use of dose reduction algorithms when measuring dose, which leads to better dose estimation and/or better understanding of dose delivery. Doses from a standard CTDI phantom and the newly-designed phantoms were compared to doses measured in air. Iterative reconstruction is a promising technique in MDCT dose reduction and artifacts correction. Iterative reconstruction algorithms have been developed to address specific imaging tasks as is the case with Iterative Metal Artifact Reduction or iMAR which was developed by Siemens and is to be in use with the companys future computed tomography platform. The goal of iMAR is to reduce metal artifact when imaging patients with metal implants and recover CT number of tissues adjacent to the implant. This research evaluated i

  2. Finger fractures imaging: accuracy of cone-beam computed tomography and multislice computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Faccioli, Niccolo; Foti, Giovanni; Barillari, Marco; Mucelli, Roberto Pozzi [University of Verona, Department of Radiology, G.B. Rossi Hospital, Verona (Italy); Atzei, Andrea [University of Verona, Department of Hand Surgery, G.B. Rossi Hospital, Verona (Italy)

    2010-11-15

    To compare the diagnostic accuracy and radiation exposure of cone beam computed tomography (CBCT) and multislice computed tomography (MSCT) in the evaluation of finger fractures. In a 3-year period, 57 consecutive patients with post-traumatic fractures of the metacarpal-phalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints with involvement of the articular surface were studied by means of CBCT and MSCT. Student's t test was used to compare CBCT and MSCT accuracy in evaluating the percentage of joint surface involvement and in detecting bone fragments. The average tissue-absorbed doses of CBCT and MSCT were also compared. A value of p < 0.05 was considered statistically significant. Inter-observer agreement was calculated. In all cases, CBCT allowed the percentage of articular involvement to be correctly depicted compared with MSCT, showing 100% sensitivity and specificity (p < 0.001). A total of 103 bone fragments were depicted on MSCT (mean 3.8 per patient, range 1-23). CBCT indicated 92 out of 103 fragments (89.3%) compared with MSCT (mean diameter of missed fragments 0.9 mm, range 0.6-1.3 mm), with no statistically significant difference between CBCT and MSCT (p < 0.025). Multislice CT radiation exposure was significantly higher than that of CBCT (0.18 mSv vs 0.06 mSv, p < 0.0025). Inter-observer agreement was good (overall {kappa} = 0.89-0.96). Cone beam CT may be considered a valuable imaging tool in the preoperative assessment of finger fractures, when MSCT is not available. (orig.)

  3. The Western Denmark Cardiac Computed Tomography Registry

    DEFF Research Database (Denmark)

    Nielsen, Lene Hüche; Nørgaard, Bjarne Linde; Tilsted, Hans-Henrik

    2014-01-01

    BACKGROUND: As a subregistry to the Western Denmark Heart Registry (WDHR), the Western Denmark Cardiac Computed Tomography Registry (WDHR-CCTR) is a clinical database established in 2008 to monitor and improve the quality of cardiac computed tomography (CT) in Western Denmark. OBJECTIVE: We......-CCTR, showed that coronary CT angiographies accounted for only 23% of all nonregistered cardiac CTs, indicating >90% completeness of coronary CT angiographies in the WDHR-CCTR. The completeness of individual variables varied substantially (range: 0%-100%), but was >85% for more than 70% of all variables. Using......, making it a valuable tool for clinical epidemiological research....

  4. Transcaval Ureter: Multidetector Computed Tomography Demonstration.

    Science.gov (United States)

    Sofia, Carmelo; Racchiusa, Sergio; Magno, Carlo; Inferrera, Antonino; Donato, Rocco; Mucciardi, Giuseppe; Mazziotti, Silvio; Ascenti, Giorgio

    2015-07-01

    Transcaval ureter is a rare congenital anomaly characterized by an inferior cava vein duplication producing a vascular ring around the right ureter, usually determining hydroureteronephrosis. The knowledge of this vascular anomaly on imaging examinations permits to avoid erroneous diagnosis of retroperitoneal masses or adenopathy and preoperatively advise the surgeon of potential sources of complications. We describe a case of transcaval ureter studied with multidetector computed tomography. To our knowledge, this is the first case in which computed tomography multiplanar and volume-rendering reconstructions show this rare anomaly. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... a small burst of radiation passes through the body, recording an image on photographic film or a special image recording ... this series of pictures, or slices of the body, to create two-dimensional cross-sectional images, which are then displayed on a monitor. Special ...

  6. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... child may have, and if there is a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may influence the decision on ... levels of radiation may cause cancer. However, CT scans result in a low-level ...

  7. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... accurate diagnosis far outweighs the risk. See the Safety page for more information about radiation dose. There ...

  8. {sup 18}F-Choline Positron Emission Tomography/Computed Tomography–Driven High-Dose Salvage Radiation Therapy in Patients With Biochemical Progression After Radical Prostatectomy: Feasibility Study in 60 Patients

    Energy Technology Data Exchange (ETDEWEB)

    D' Angelillo, Rolando M., E-mail: r.dangelillo@unicampus.it [Radiation Oncology, Campus Bio-Medico University, Rome (Italy); Sciuto, Rosa [Department of Nuclear Medicine, Regina Elena National Cancer Institute, Rome (Italy); Ramella, Sara [Radiation Oncology, Campus Bio-Medico University, Rome (Italy); Papalia, Rocco [Department of Urology, Regina Elena National Cancer Institute, Rome (Italy); Jereczek-Fossa, Barbara A. [Department of Radiation Oncology, European Institute of Oncology, Milan (Italy); Department of Health Sciences, University of Milan, Milan (Italy); Trodella, Luca E.; Fiore, Michele [Radiation Oncology, Campus Bio-Medico University, Rome (Italy); Gallucci, Michele [Department of Urology, Regina Elena National Cancer Institute, Rome (Italy); Maini, Carlo L. [Department of Nuclear Medicine, Regina Elena National Cancer Institute, Rome (Italy); Trodella, Lucio [Radiation Oncology, Campus Bio-Medico University, Rome (Italy)

    2014-10-01

    Purpose: To retrospectively review data of a cohort of patients with biochemical progression after radical prostatectomy, treated according to a uniform institutional treatment policy, to evaluate toxicity and feasibility of high-dose salvage radiation therapy (80 Gy). Methods and Materials: Data on 60 patients with biochemical progression after radical prostatectomy between January 2009 and September 2011 were reviewed. The median value of prostate-specific antigen before radiation therapy was 0.9 ng/mL. All patients at time of diagnosis of biochemical recurrence underwent dynamic {sup 18}F-choline positron emission tomography/computed tomography (PET/CT), which revealed in all cases a local recurrence. High-dose salvage radiation therapy was delivered up to total dose of 80 Gy to 18F-choline PET/CT-positive area. Toxicity was recorded according to the Common Terminology Criteria for Adverse Events, version 3.0, scale. Results: Treatment was generally well tolerated: 54 patients (90%) completed salvage radiation therapy without any interruption. Gastrointestinal grade ≥2 acute toxicity was recorded in 6 patients (10%), whereas no patient experienced a grade ≥2 genitourinary toxicity. No grade 4 acute toxicity events were recorded. Only 1 patient (1.7%) experienced a grade 2 gastrointestinal late toxicity. With a mean follow-up of 31.2 months, 46 of 60 patients (76.6%) were free of recurrence. The 3-year biochemical progression-free survival rate was 72.5%. Conclusions: At early follow-up, {sup 18}F-choline PET/CT-driven high-dose salvage radiation therapy seems to be feasible and well tolerated, with a low rate of toxicity.

  9. Computed tomography findings in delirium.

    Science.gov (United States)

    Koponen, H; Hurri, L; Stenbäck, U; Mattila, E; Soininen, H; Riekkinen, P J

    1989-04-01

    Computerized tomography of the head was carried out on 69 elderly patients who met the DSM-III criteria for delirium and 31 neurological controls in order to evaluate the focal changes and generalized brain atrophy associated with delirium. Neither the difference between the mean ages nor the sex distribution in these groups was statistically significant. The delirious patients differed from the controls significantly in ventricular dilatation and cortical atrophy, and there was a statistically significant correlation between the width of the sylvian fissure and Mini-Mental State Examination score. Focal changes were also statistically more common in the delirious patients, and these changes tended to concentrate in the high-order association areas of the right hemisphere. Results suggest a marked predisposing role for the structural brain diseases (primary degenerative and multi-infarct type dementias, parkinsonism) in the development of delirium in elderly patients.

  10. Comparison of radiation dose and image quality of triple-rule-out computed tomography angiography between conventional helical scanning and a strategy incorporating sequential scanning.

    Science.gov (United States)

    Manheimer, Eric D; Peters, M Robert; Wolff, Steven D; Qureshi, Mehreen A; Atluri, Prashanth; Pearson, Gregory D N; Einstein, Andrew J

    2011-04-01

    Triple-rule-out computed tomographic angiography (TRO CTA), performed to evaluate the coronary arteries, pulmonary arteries, and thoracic aorta, has been associated with high radiation exposure. The use of sequential scanning for coronary computed tomographic angiography reduces the radiation dose. The application of sequential scanning to TRO CTA is much less well defined. We analyzed the radiation dose and image quality from TRO CTA performed at a single outpatient center, comparing the scans from a period during which helical scanning with electrocardiographically controlled tube current modulation was used for all patients (n = 35) and after adoption of a strategy incorporating sequential scanning whenever appropriate (n = 35). Sequential scanning was able to be used for 86% of the cases. The sequential-if-appropriate strategy, compared to the helical-only strategy, was associated with a 61.6% dose decrease (mean dose-length product of 439 mGy × cm vs 1,144 mGy × cm and mean effective dose of 7.5 mSv vs 19.4 mSv, respectively, p strategy (326 mGy × cm vs 1,141 mGy × cm and 5.5 mSv vs 19.4 mSv, respectively, p strategies, a nonstatistically significant trend was seen toward better quality in the sequential protocol than in the helical protocol. In conclusion, approaching TRO CTA with a diagnostic strategy of sequential scanning, as appropriate, can offer a marked reduction in the radiation dose while maintaining the image quality. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... be viewed on a computer monitor, printed on film or transferred to a CD or DVD. CT ... through the body, recording an image on photographic film or a special image recording plate . Bones appear ...

  12. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... slices. When the image slices are reassembled by computer software, the result is a very detailed multidimensional view of the body's interior. Refinements in detector technology allow new CT scanners to obtain multiple slices ...

  13. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... appears black. With CT scanning, numerous x-ray beams and a set of electronic x-ray detectors ... through the scanner, so that the x-ray beam follows a spiral path. A special computer program ...

  14. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... which are then displayed on a monitor. Special software can also generate three-dimensional (3-D) images ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ...

  15. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... These images can be viewed on a computer monitor, printed on film or transferred to a CD ... for injury after trauma, diagnose and stage cancer, monitor response to treatment for cancer, and diagnose and ...

  16. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... child may have, and if there is a history of heart disease, asthma, diabetes, kidney disease or ... a gantry, which rotates around the patient. The computer that processes the imaging information and monitor are ...

  17. Paradoxical emboli: demonstration using helical computed tomography of the pulmonary artery associated with abdominal computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Delalu, P.; Ferretti, G.R.; Bricault, I.; Ayanian, D.; Coulomb, M. [Service Central de Radiologie et Imagerie Medicale, CHU Grenoble (France)

    2000-02-01

    We report the case of a 60-year-old woman with a recent history of a cerebrovascular accident. Because of clinical suspicion of pulmonary embolism and negative Doppler ultrasound findings of the lower limbs, spiral computed tomography of the pulmonary artery was performed and demonstrated pulmonary emboli. We emphasize the role of computed tomography of the abdomen, performed 3 min after the thoracic acquisition, which showed an unsuspected thrombus within the abdominal aorta and the left renal artery with infarction of the left kidney. Paradoxical embolism was highly suspected on computed tomography data and confirmed by echocardiography which demonstrated a patent foramen ovale. (orig.)

  18. Computed tomography evaluation of petrous bone fractures ...

    African Journals Online (AJOL)

    Background: Petrous bone trauma is the sequel of blunt head injury and can have life threatening complications resulting in immediate mortality. Early detection and good knowledge of the Computed Tomography (CT) findings ensure prompt treatment of both fractures and complications. Objective: To document the ...

  19. Computed tomography in untreated congenital adrenal hyperplasia

    Energy Technology Data Exchange (ETDEWEB)

    Harinarayana, C.V.; Renu, G.; Ammini, A.C.; Khurana, M.L.; Ved, P.; Karmarkar, M.G.; Ahuja, M.M.S.; Berry, M. (AIIMS, New Delhi (India))

    1991-02-01

    Six children with untreated congenital adrenal hyperplasia (CAH) were examined by computed tomography (CT). Three cases demonstrated diffuse enlargement of both adrenal glands with preservation of normal configuration and two showed tumorous transformation in one of the enlarged glands. One had equivocal in this group (age 2 years) also showed bilateral hyperplasia. (orig.).

  20. Cone beam computed tomography in veterinary dentistry

    NARCIS (Netherlands)

    van Thielen, B.; Siguenza, F.; Hassan, B.

    2012-01-01

    The purpose of this study was to assess the feasibility of cone beam computed tomography (CBCT) in imaging dogs and cats for diagnostic dental veterinary applications. CBCT scans of heads of six dogs and two cats were made. Dental panoramic and multi-planar reformatted (MPR) para-sagittal

  1. Computed Tomography Study Of Complicated Bacterial Meningitis ...

    African Journals Online (AJOL)

    To monitor the structural intracranial complications of bacterial meningitis using computed tomography (CT) scan. Retrospective study of medical and radiological records of patients who underwent CT scan over a 4 year period. AUniversityTeachingHospital in a developing country. Thirty three patients with clinically and ...

  2. Positron computed tomography with fluorodeoxyglucose; TEP FDG

    Energy Technology Data Exchange (ETDEWEB)

    Hervouet, T.; Kraeber-Bodere, F.; Lamy, T.; Le Gouil, S.; Devillers, A.; Bodet-Milin, C.; Ansquer, C.; Cheze-le Rest, C.; Metges, J.P.; Teyton, P.; Lozach, P.; Volant, A.; Bizais, Y.; Visvikis, D.; Morel, O.; Girault, S.; Soulie, P.; Dupoiron, D.; Berthelot, C.; Lorimier, G.; Jallet, P.; Garin, E.; Prigent, F.; Lesimple, T.; Barge, M.L.; Rousseau, C.; Devillers, A.; Bernard, A.M.; Bouriel, C.; Bridji, B.; Resche, R.; Banayan, S.; Claret, M.; Ninet, J.; Janier, M.; Billotey, C.; Garin, E.; Devillers, A.; Becker, S.; Lecloirec, J.; Boucher, E.; Raoul, J.L.; Rolland, V.; Oudoux, A.; Valette, F.; Dupas, B.; Moreau, P.; Champion, L.; Anract, P.; Wartski, M.; Laurence, V.; Goldwasser, F.; Pecking, A.P.; Alberini, J.L.; Brillouet, S.; Caselles, O.; Allal, B.; Zerdoud, S.; Gansel, M.G.; Thomas, F.; Dierrickx, L.; Delord, J.P.; Marchand, C.; Resche, I.; Mahe, M.A

    2006-09-15

    Several oral communications present the interest of positron computed tomography with fluorodeoxyglucose in the detection of cancers, or for the follow up of cancers treatments in order to detect early possible relapses.PET FDG is also used to optimize the definition of target volume in order to avoid side effects and to get a better control of the illness. (N.C.)

  3. Comparison on Computed Tomography using industrial items

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; De Chiffre, Leonardo

    2014-01-01

    In a comparison involving 27 laboratories from 8 countries, measurements on two common industrial items, a polymer part and a metal part, were carried out using X-ray Computed Tomography. All items were measured using coordinate measuring machines before and after circulation, with reference...

  4. Computed tomography of anorexia nervosa.

    Science.gov (United States)

    Kohlmeyer, K; Lehmkuhl, G; Poutska, F

    1983-01-01

    Computed tomographic studies were performed in patients with anorexia nervosa to confirm the observations of other authors on so-called reversible cerebral atrophy. In 21 of 23 cases a marked enlargement of the cortical sulci and the interhemispheric fissures was observed, which was reversed in a second computed tomographic study in 11 patients 4 weeks after they had reached normal weight. Psychological tests were carried out at the same time as the computed tomographic studies to correlate the changes in the brain tissue with cerebral function. Data obtained in each group of tests for both the initial and the follow-up studies were analyzed using the Student t-test. The differences were found to be statistically significant (p = 0.01 in most cases). The results indicate that anorexia nervosa is not only a psychodynamic problem, but also one in which an organic brain lesion plays an important role during the course of the illness.

  5. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... detectors rotate around the patient. At the same time, the examination table is moving through the scanner, so that the x-ray beam follows a spiral path. A special computer program processes this series of pictures, or slices ...

  6. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed ...

  7. Principles of multidetector-row computed tomography. Pt. 2. Determinants of radiation exposure and current technical developments; Grundlagen der Mehrzeilendetektor-Computertomographie. T. 2. Einflussfaktoren der Strahlenexposition und aktuelle technische Entwicklungen

    Energy Technology Data Exchange (ETDEWEB)

    Stiller, W. [Universitaetsklinikum Heidelberg, Abteilung fuer Diagnostische und Interventionelle Radiologie, Heidelberg (Germany)

    2011-12-15

    In the field of multidetector-row computed tomography (MDCT) technical improvements have constantly extended the range of clinical applications and made new radiodiagnostic indications accessible. Whereas previous technical improvements were primarily aimed at the imaging of anatomy with high spatial and temporal resolution, nowadays a trend towards quantitative and functional imaging using computed tomography (CT) beyond the pure depiction of morphology is on the horizon: Currently the focus of technical developments is in the domain of spectral (energy-resolved) CT imaging and in the introduction of very wide multi-row detectors with large z-coverage. In addition, there is great interest in technical approaches for reducing radiation exposure of the patients caused by (spiral) MDCT, as the increasing range of its clinical applications as well as some of the recent technical advances involve the risk of increased radiation exposure. The use of iterative image reconstruction techniques in MDCT represents a particularly promising technical approach for the reduction of radiation exposure. (orig.) [German] Technische Weiterentwicklungen auf dem Gebiet der Mehrzeilendetektor-Computertomographie (MDCT) haben deren klinisch-radiologisches Einsatzspektrum staendig erweitert und neue roentgendiagnostische Indikationen erschlossen. Waehrend bisherige technische Neuerungen primaer auf eine raeumlich wie zeitlich hochaufgeloeste Darstellung der Anatomie abzielten, zeichnet sich heute jenseits der reinen Darstellung der Morphologie ein Trend hin zur quantitativen und funktionellen Bildgebung mittels der Computertomographie (CT) ab: Derzeit liegt der Fokus technischer Entwicklungen im Bereich der spektralen (energieaufgeloesten) CT-Bildgebung und der Einfuehrung sehr breiter Mehrzeilendetektoren mit grosser z-Abdeckung. Von grossem Interesse sind zudem technische Ansaetze zur Reduktion der durch die (Spiral-)MDCT verursachten Strahlenexposition der Patienten, da sowohl das

  8. Cerebral candidiasis. Computed tomography appearance

    Energy Technology Data Exchange (ETDEWEB)

    Chaabane, M.; Ladeb, M.F.; Bouhaouala, M.H.; Ben Hammouda, M.; Ataalah, R.; Gannouni, A.; Krifa, H.

    1989-07-01

    A three year old child who had been suffering from oral candidiasis since the age of 1 year presented with osteitis of the clavicle, 2 cerebral frontal abscesses and an occipital abscess which extended across the calvaria and was associated with osteolysis. Histological and microbiological studies following surgery confirmed the diagnosis of candidiasis in this girl who was found to have IgA immunodefinciency. The authors report the computed tomographic appearance of the cerebral lesions and review the literature. (orig.).

  9. Proton computed tomography images with algebraic reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzi, M. [Physics and Astronomy Department, University of Florence, Florence (Italy); Civinini, C.; Scaringella, M. [INFN - Florence Division, Florence (Italy); Bonanno, D. [INFN - Catania Division, Catania (Italy); Brianzi, M. [INFN - Florence Division, Florence (Italy); Carpinelli, M. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Chemistry and Pharmacy Department, University of Sassari, Sassari (Italy); Cirrone, G.A.P.; Cuttone, G. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Presti, D. Lo [INFN - Catania Division, Catania (Italy); Physics and Astronomy Department, University of Catania, Catania (Italy); Maccioni, G. [INFN – Cagliari Division, Cagliari (Italy); Pallotta, S. [INFN - Florence Division, Florence (Italy); Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence (Italy); SOD Fisica Medica, Azienda Ospedaliero-Universitaria Careggi, Firenze (Italy); Randazzo, N. [INFN - Catania Division, Catania (Italy); Romano, F. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Sipala, V. [INFN - Laboratori Nazionali del Sud, Catania (Italy); Chemistry and Pharmacy Department, University of Sassari, Sassari (Italy); Talamonti, C. [INFN - Florence Division, Florence (Italy); Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence (Italy); SOD Fisica Medica, Azienda Ospedaliero-Universitaria Careggi, Firenze (Italy); Vanzi, E. [Fisica Sanitaria, Azienda Ospedaliero-Universitaria Senese, Siena (Italy)

    2017-02-11

    A prototype of proton Computed Tomography (pCT) system for hadron-therapy has been manufactured and tested in a 175 MeV proton beam with a non-homogeneous phantom designed to simulate high-contrast material. BI-SART reconstruction algorithms have been implemented with GPU parallelism, taking into account of most likely paths of protons in matter. Reconstructed tomography images with density resolutions r.m.s. down to ~1% and spatial resolutions <1 mm, achieved within processing times of ~15′ for a 512×512 pixels image prove that this technique will be beneficial if used instead of X-CT in hadron-therapy.

  10. Dose estimation for paediatric cranial computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Curci Daros, K.A.; Bitelli Medeiros, R. [Sao Paulo Univ. Federal (Brazil); Curci Daros, K.A.; Oliveira Echeimberg, J. de [Centro Univ. Sao Camilo, Sao Paulo (Brazil)

    2006-07-01

    In the last ten years, the number of paediatric computed tomography (CT) scans have increased worldwide, contributing to higher population radiation dose. Technique diversification in paediatrics and different CT equipment technologies have led to various exposure levels complicating precise evaluation of doses and operational conditions necessary for good quality images. The objective of this study was to establish a quantitative relationship between absorbed dose and cranial region in children up to 6 years old undergoing CT exams. Methods: X-ray was measured on the cranial surface of 64 patients undergoing CT using thermoluminescent (T.L.) dosimeters. Forty T.L.D.100 thermoluminescent dosimeters (T.L.D.) were evenly distributed on each patients skin surface along the sagittal axis. Measurements were performed in facial regions exposed to scatter radiation and in the supratentorial and posterior fossa regions, submitted to primary radiation. T.L.D. were calibrated for 120 kV X-ray over the acrylic phantom. T.L. measurements were made with a Harshaw 4000 system. Patient mean T.L. readings were determined for position, pi, of T.L.D. and normalized to the maximum supratentorial reading. From integrating the linear T.L. density function (?) resulting from radiation distribution in each of the three exposed regions, dose fraction was determined in the region of interest, along with total dose under the technical conditions used in that specific exam protocol. For each T.L.D. position along the patient cranium, there were n T.L. measurements with 2% uncertainty due to T.L. reader, and 5% due to thermal treatment of dosimeters. Also, mean T.L. readings and their uncertainties were calculated for each patient at each position, p. Results: Mean linear T.L. density for the region exposed to secondary radiation defined by position, 0.3{<=}p{<=}6 cm, was {rho}((p)=7.9(4)x10{sup -2}+7(5)x10{sup -5}p{sup 4.5(4)} cm{sup -1}; exposed to primary X-ray for the posterior fossa

  11. Computed Tomography in Forensic Medicine

    DEFF Research Database (Denmark)

    Leth, Peter Mygind

    2015-01-01

    to disease and injury diagnoses? 3. Can PMCT be used as a screening tool for selecting cases for autopsy, and can PMCT in some cases substitute for autopsy? 4. What is the inter-observer variation in PMCT? Who should evaluate the images? 5. How much new information is obtained by the histological examination...... was not used. Autopsies were performed according to the Danish government's official guidelines. PMCT and autopsy findings were interpreted independent of each other. Diagnoses, including the cause of death and histology findings, were registered in a computer database (SPSS) together with information about...... with a high AIS severity score. 5. Importance of histology: The histological examination confirmed the autopsy findings in 59% of all cases. Important new information was obtained in 23% of cases, and some, but less important, new information was obtained in 15% of cases. There were significantly fewer...

  12. Computed tomography of renal oncocytoma

    Energy Technology Data Exchange (ETDEWEB)

    Levine, E. (Univ. of Kansas, Kansas City); Huntrakoon, M.

    1983-10-01

    Renal oncocytoma is a relatively rare tumor that has an excellent prognosis and usually may be treated adequately by local resection. Preoperative differentiation from renal cell carcinoma, which requires radical nephrectomy, is thus of importance. The computed tomographic (CT) and pathologic features of three incidentally-detected renal oncocytomas were compared with those of six renal cell carcinomas of comparable size. Renal cell carcinoma appears on CT as a solid mass that generally has an indistinct interface with normal renal parenchyma, a lobulated contour, and a nonhomogeneous pattern of contrast enhancement. These features correlate with the pathologic findings of an irregular tumor margin and the frequent presence of tumor hemorrhage and necrosis. Oncocytoma, on the other hand, generally has a distinct margin, a smooth contour, and a homogeneous appearance on contrast-enhanced CT scans. These findings correlate with a smooth tumor margin and absence of tumor hemorrhage and necrosis on pathologic examination. These features are not pathognomonic of oncocytoma, as angiographic evidence suggests that renal cell carcinoma may show both distinct margination and a homogeneous blush in 6% of cases. However, their demonstration by CT should alert radiologists and surgeons to the possibility that a renal mass may be an oncocytoma. Such a presumptive diagnosis then can lead to a surgical approach that allows for renal-conserving surgery.

  13. Comparative evaluation of computed tomography for dental implants on the mandibular edentulous area

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kyung Hoon; Jeong, Ho Gul; Park, Hyok; Park, Chang Seo; Kim, Kee Deog [Department of Oral and Maxillofacial Radiology, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul (Korea, Republic of)

    2009-03-15

    The purpose of this study was to evaluate the clinical usefulness of the recently developed multi-detector computed tomography and cone beam computed tomography in pre-operative implant evaluation, by comparing them with the single detector computed tomography, already confirmed for accuracy in this area. Five partially edentulous dry human mandibles, with 1 X 1 mm gutta percha cones, placed in 5 mm intervals posterior to the mental foramen on each side of the buccal part of the mandible, were used in this study. They were scanned as follows: 1) Single detector computed tomography: slice thickness 1 mm, 200 mA, 120 kV 2) Multi-detector computed tomography: slice thickness 0.75 mm, 250 mA, 120 kV 3) Cone beam computed tomography: 15 mAs, 120 kV Axial images acquired from three computed tomographs were transferred to personal computer, and then reformatted cross-sectional images were generated using V-Implant 2.0 (CyberMed Inc., Seoul, Korea) software. Among the cross-sectional images of the gutta percha cone, placed in the buccal body of the mandible, the most precise cross section was selected as the measuring point and the distance from the most superior border of the mandibular canal to the alveolar crest was measured and analyzed 10 times by a dentist. There were no significant intraobserver differences in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). There were no significant differences among single detector computed tomography, multi-detector computed tomography and cone beam computed tomography in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). Multi-detector computed tomography and cone beam computed tomography are clinically useful in the evaluation of pre-operative site for mandibular dental implants, with consideration for radiation exposure dose and scanning time.

  14. Contrast-induced nephropathy after computed tomography

    Directory of Open Access Journals (Sweden)

    Luciano da Silva Selistre

    2015-03-01

    Full Text Available Introduction: Contrast induced nephropathy is the third most prevalent preventable cause of acute kidney injury in hospitalized patients. It defined as an absolute increase in serum creatinine ≥ 0.5 mg/dL and relative ≥ 25% increase. Objective: We studied the risk factors to intravenous injection contrast nephropathy after computed tomography. Methods: We studied 400 patients prospectively. Results: The incidence of contrast induced nephropathy, with an absolute or a relative increase were 4.0% and 13.9%, respectively. Diabetes and cardiac failure were independent risk factors for CIN a relative increase de serum creatinine (O.R.: 3.5 [95% CI: 1.92-6.36], p < 0.01, 2.61 [95% CI: 1.14-6.03%], p < 0.05, respectively. Conclusions: We showed association between uses of intravenous injection contrast after computed tomography with acute injury renal, notably with diabetes and heart failure.

  15. The Western Denmark Cardiac Computed Tomography Registry

    DEFF Research Database (Denmark)

    Nielsen, Lene Hüche; Nørgaard, Bjarne Linde; Tilsted, Hans-Henrik

    2014-01-01

    BACKGROUND: As a subregistry to the Western Denmark Heart Registry (WDHR), the Western Denmark Cardiac Computed Tomography Registry (WDHR-CCTR) is a clinical database established in 2008 to monitor and improve the quality of cardiac computed tomography (CT) in Western Denmark. OBJECTIVE: We...... examined the content, data quality, and research potential of the WDHR-CCTR. METHODS: We retrieved 2008-2012 data to examine the 1) content; 2) completeness of procedure registration using the Danish National Patient Registry as reference; 3) completeness of variable registration comparing observed vs...... expected numbers; and 4) positive predictive values as well as negative predictive values of 19 main patient and procedure variables. RESULTS: By December 31, 2012, almost 22,000 cardiac CTs with up to 40 variables for each procedure have been registered. Of these, 87% were coronary CT angiography...

  16. Computed tomography in renal replacement lipomatosis

    Energy Technology Data Exchange (ETDEWEB)

    Kullendorff, B.; Nyman, U.; Aspelin, P.

    Replacement lipomatosis of the kidney is the result of severe atrophy of destruction of the renal parenchyma often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. The diagnosis is difficult to establish with conventional radiographic methods. Though ultrasonography may show highly suggestive findings, computed tomography seems to be the most accurate method in demonstrating the distinctive features of replacement lipomatosis, i.e. a rim of the destroyed renal parenchyma adjacent to a lipomatous mass with attentuation values similar to those of normal fat and calculi. This entity should readily be differentiated from fat-containing tumors in the kidney or its vicinity by computed tomography. When surgery is contemplated CT may also be of value to determine the extension of the fibrous fatty tissue relative to adjacent organs and possible abscess formation.

  17. Computed Tomography Biomarkers of Vulnerable Coronary Plaques

    Directory of Open Access Journals (Sweden)

    Nyulas Tiberiu

    2016-12-01

    Full Text Available An unstable plaque has a high risk of thrombosis and at the same time for a fast progression of the stenosis degree. Also, “high-risk plaque” and “thrombosis-prone plaque” are used as synonym terms for characterization of a vulnerable plaque. The imaging biomarkers for vulnerable coronary plaques are considered to be spotty calcifications, active remodeling, low-density atheroma and the presence of a ring-like attenuation pattern, also known as the napkin-ring sign. Computed cardiac tomography can determine the plaque composition by assessing the plaque density, which is measured in Hounsfield units (HU. The aim of this manuscript was to provide an update about the most frequently used biomarkers of vulnerability in a vulnerable plaque with the help of computed cardiac tomography.

  18. 256-slice wide-detector computed tomography.

    Science.gov (United States)

    2007-11-01

    This article provides opinions and predictions about an emerging technology-256-slice wide-detector computed tomography-to help healthcare facilities decide whether the technology is worth tracking and when it might be ready for adoption. We believe 256-slice CT is worth monitoring based on its predicted clinical and business impact. We consider it unlikely, however, that more than a few select facilities will begin adopting this technology within the next three years.

  19. Encapsulating peritonitis: computed tomography and surgical correlation

    Energy Technology Data Exchange (ETDEWEB)

    Kadow, Juliana Santos; Fingerhut, Carla Jeronimo Peres; Fernandes, Vinicius de Barros; Coradazzi, Klaus Rizk Stuhr; Silva, Lucas Marciel Soares; Penachim, Thiago Jose, E-mail: vinicius.barros.fernandes@gmail.com [Pontificia Universidade Catolica de Campinas (PUC-Campinas), Campinas, SP (Brazil). Hospital e Maternidade Celso Pierro

    2014-07-15

    Sclerosing encapsulating peritonitis is a rare and frequently severe entity characterized by total or partial involvement of small bowel loops by a membrane of fibrous tissue. The disease presents with nonspecific clinical features of intestinal obstruction, requiring precise imaging diagnosis to guide the treatment. The present report emphasizes the importance of computed tomography in the diagnosis of this condition and its confirmation by surgical correlation. (author)

  20. Computed Tomography Manifestations of Renal Hemangiopericytoma

    Energy Technology Data Exchange (ETDEWEB)

    Hayasaka, K.; Nihashi, T.; Nojiri, Y.; Okamuara, K. [Depts. of Radiology and Urology, National Center Hospital for Geriatric Medicine, Ohbu (Japan)

    2007-10-15

    Renal hemangiopericytoma (HPC) is a rare tumor. There are no unique radiological findings that can reliably aid in its preoperative diagnosis. A 60-year-old Japanese male was admitted for an abdominal mass. Ultrasound revealed a heterogeneous hyperechoic mass. Computed tomography (CT) showed a heterogeneous mass and tumor vascularity by a precontrast and dynamic study with maximum intensity projection (MIP) and volume-rendering technique (VRT). Radical nephrectomy was performed, and the histopathogic diagnosis revealed renal HPC.

  1. Targeted concurrent chemoradiotherapy, by using improved microcapsules that release carboplatin in response to radiation, improves detectability by computed tomography as well as antitumor activity while reducing adverse effect in vivo.

    Science.gov (United States)

    Harada, Satoshi; Ehara, Shigeru; Ishii, Keizo; Sato, Takahiro; Koka, Masashi; Kamiya, Tomihiro; Sera, Koichiro; Goto, Shyoko

    2015-03-01

    The effect of alginate-hyaluronate microcapsules that release carboplatin in response to radiation was improved by adding ascorbic acid (AA). Four measures of the effectiveness of the microcapsules were evaluated: 1) release of carboplatin in response to radiation in vitro and in vivo; 2) detectability of their accumulation by computed tomography (CT) in vivo; 3) enhancement of antitumor effects in vivo; and 4) reduction of adverse effects in vivo. There were significant increases in the rupture of microcapsules by adding AA in vitro. Subcutaneously injected microcapsules around the tumor could be detected by using CT and the alteration of CT-values correlated with the accumulation of the microcapsules. Those microcapsules released carboplatin and resulted in synergistic antitumor effect with concomitant radiation. With the encapsulation of carboplatin, chemotherapeutic effects were still observed two weeks after treatment. However, addition of AA did not result in increased antitumor effect in vivo. A reduction in adverse effects was observed with the encapsulation of carboplatin, through localization of carboplatin around the tumor. Addition of AA to the materials of microcapsules did not result in increasing antitumor effect. However encapsulation of carboplatin will be useful as a clinical cancer-therapy option. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  2. Knowledge-based iterative model reconstruction technique in computed tomography of lumbar spine lowers radiation dose and improves tissue differentiation for patients with lower back pain

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Cheng Hui [Department of Medical Imaging, Pojen General Hopsital, Taipei, Taiwan (China); School of Medicine, National Yang-Ming University, Taipei, Taiwan (China); Wu, Tung-Hsin [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan (China); Lin, Chung-Jung, E-mail: bcjlin@me.com [School of Medicine, National Yang-Ming University, Taipei, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China); Chiou, Yi-You; Chen, Ying-Chou; Sheu, Ming-Huei; Guo, Wan-Yuo; Chiu, Chen Fen [School of Medicine, National Yang-Ming University, Taipei, Taiwan (China); Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan (China)

    2016-10-15

    Highlights: • Knowledge-based IMR improves tissue differentiation in CT of L-spine better than hybrid IR (iDose{sup 4}). • Higher strength IMR improves image qualities of the IVD and IVF in spinal stenosis. • IMR provides diagnostic lower dose CT of L-spine. - Abstract: Purpose: To evaluate the image quality and diagnostic confidence of reduced-dose computed tomography (CT) of the lumbar spine (L-spine) reconstructed with knowledge-based iterative model reconstruction (IMR). Materials and methods: Prospectively, group A consisted of 55 patients imaged with standard acquisition reconstructed with filtered back-projection. Group B consisted of 58 patients imaged with half tube current, reconstructed with hybrid iterative reconstruction (iDose{sup 4}) in Group B1 and knowledge-based IMR in Group B2. Signal-to-noise ratio (SNR) of different regions, the contrast-to-noise ratio between the intervetebral disc (IVD) and dural sac (D-D CNR), and subjective image quality of different regions were compared. Higher strength IMR was also compared in spinal stenosis cases. Results: The SNR of the psoas muscle and D-D CNR were significantly higher in the IMR group. Except for the facet joint, subjective image quality of other regions including IVD, intervertebral foramen (IVF), dural sac, peridural fat, ligmentum flavum, and overall diagnostic acceptability were best for the IMR group. Diagnostic confidence of narrowing IVF and IVD was good (kappa = 0.58–0.85). Higher strength IMR delineated IVD better in spinal stenosis cases. Conclusion: Lower dose CT of L-spine reconstructed with IMR demonstrates better tissue differentiation than iDose{sup 4} and standard dose CT with FBP.

  3. Risk of cancer incidence before the age of 15 years after exposure to ionising radiation from computed tomography: results from a German cohort study

    Energy Technology Data Exchange (ETDEWEB)

    Krille, L. [University Medical Center Mainz, Institute of Medical Biostatistics, Epidemiology and Informatics, Mainz (Germany); International Agency for Research on Cancer, Lyon (France); Dreger, S.; Zeeb, H. [University of Bremen, Leibniz - Institute for Prevention Research and Epidemiology - BIPS, Research Focus Health Sciences Bremen, Bremen (Germany); Schindel, R.; Blettner, M. [University Medical Center Mainz, Institute of Medical Biostatistics, Epidemiology and Informatics, Mainz (Germany); Albrecht, T. [Vivantes, Klinikum Neukoelln, Institut fuer Radiologie und Interventionelle Therapie, Berlin (Germany); Asmussen, M. [Zentralinstitut fuer Bildgebende Diagnostik, Staedtisches Klinikum Karlsruhe, Karlsruhe (Germany); Barkhausen, J. [Universitaetsklinikum Schleswig Holstein, Klinik fuer Radiologie und Nuklearmedizin, Campus Luebeck, Luebeck (Germany); Berthold, J.D. [Medizinische Hochschule Hannover, Institut fuer Diagnostische und Interventionelle Radiologie, Hannover (Germany); Chavan, A. [Klinikum Oldenburg GmbH, Institut fuer Diagnostische and Interventionelle Radiologie, Oldenburg (Germany); Claussen, C. [Universitaetsklinikum Tuebingen, Abt. fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Forsting, M. [Universitaetsklinikum Essen, Institut fuer Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen (Germany); Gianicolo, E.A.L. [University Medical Center Mainz, Institute of Medical Biostatistics, Epidemiology and Informatics, Mainz (Germany); National Research Council, Institute of Clinical Physiology, Lecce (Italy); Jablonka, K. [Klinikum Bremen-Mitte, Klinik fuer Radiologische Diagnostik und Nuklearmedizin, Bremen (Germany); Jahnen, A. [Centre de Recherche Public Henri Tudor, Luxembourg (Luxembourg); Langer, M. [Universitaetsklinikum Freiburg, Klinik fuer Radiologie, Freiburg (Germany); Laniado, M. [Universitaetsklinikum Carl Gustav Carus Dresden, Institut und Poliklinik fuer Radiologische Diagnostik, Dresden (Germany); Lotz, J. [Universitaetsmedizin Goettingen, Institut fuer Diagnostische und Interventionelle Radiologie, Goettingen (Germany); Mentzel, H.J. [Universitaetsklinikum Jena, Institut fuer Diagnostische und Interventionelle Radiologie, Sektion Kinderradiologie, Jena (Germany); Queisser-Wahrendorf, A. [Universitaetsmedizin Mainz, Zentrum fuer Kinder- und Jugendmedizin, Mainz (Germany); Rompel, O. [Universitaetsklinikum Erlangen, Radiologisches Institut, Erlangen (Germany); Schlick, I. [Klinikum Nuernberg Sued, Institut fuer Radiologie und Neuroradiologie, Nuremberg (Germany); Schneider, K.; Seidenbusch, M. [Institut fuer Klinische Radiologie, Klinikum der Universitaet Muenchen, Dr. von Haunersches Kinderspital, Munich (Germany); Schumacher, M. [Universitaetsklinik Freiburg, Klinik fuer Neuroradiologie, Neurozentrum, Freiburg (Germany); Spix, C. [University Medical Center Mainz, German Childhood Cancer Registry, Mainz (Germany); Spors, B. [Charite - Universitaetsmedizin Berlin, Kinderradiologie, Standort Campus Virchow Klinikum, Berlin (Germany); Staatz, G. [Universitaetsmedizin Mainz, Klinik und Poliklinik fuer diagnostische und interventionelle Radiologie, Sektion Kinderradiologie, Mainz (Germany); Vogl, T. [Klinikum der Johann Wolfgang Goethe-Universitaet Frankfurt/Main, Institut fuer Diagnostische und Interventionelle Radiologie, Frankfurt (Germany); Wagner, J. [Vivantes, Klinikum im Friedrichshain, Institut fuer Radiologie und Interventionelle Therapie, Berlin (Germany); Weisser, G. [Universitaetsklinikum Mannheim, Institut fuer Klinische Radiologie und Nuklearmedizin, Mannheim (Germany)

    2015-03-15

    The aim of this cohort study was to assess the risk of developing cancer, specifically leukaemia, tumours of the central nervous system and lymphoma, before the age of 15 years in children previously exposed to computed tomography (CT) in Germany. Data for children with at least one CT between 1980 and 2010 were abstracted from 20 hospitals. Cancer cases occurring between 1980 and 2010 were identified by stochastic linkage with the German Childhood Cancer Registry (GCCR). For all cases and a sample of non-cases, radiology reports were reviewed to assess the underlying medical conditions at time of the CT. Cases were only included if diagnosis occurred at least 2 years after the first CT and no signs of cancer were recorded in the radiology reports. Standardised incidence ratios (SIR) using incidence rates from the general population were estimated. The cohort included information on 71,073 CT examinations in 44,584 children contributing 161,407 person-years at risk with 46 cases initially identified through linkage with the GCCR. Seven cases had to be excluded due to signs possibly suggestive of cancer at the time of first CT. Overall, more cancer cases were observed (O) than expected (E), but this was mainly driven by unexpected and possibly biased results for lymphomas. For leukaemia, the SIR (SIR = O/E) was 1.72 (95 % CI 0.89-3.01, O = 12), and for CNS tumours, the SIR was 1.35 (95 % CI 0.54-2.78, O = 7). Despite careful examination of the medical information, confounding by indication or reverse causation cannot be ruled out completely and may explain parts of the excess. Furthermore, the CT exposure may have been underestimated as only data from the participating clinics were available. This should be taken into account when interpreting risk estimates. (orig.)

  4. Salvage interstitial brachytherapy based on computed tomography for recurrent cervical cancer after radical hysterectomy and adjuvant radiation therapy: case presentations and introduction of the technique

    Directory of Open Access Journals (Sweden)

    Zhong-Shan Liu

    2016-10-01

    Full Text Available Purpose : Locally recurring cervical cancer after surgery and adjuvant radiotherapy remains a major therapeutic challenge. This paper presents a new therapeutic technique for such patients: interstitial brachytherapy (BT guided by real-time three-dimensional (3D computed tomography (CT. Material and methods : Sixteen patients with recurrent cervical cancer after radical surgery and adjuvant external-beam radiotherapy (EBRT were included in this study. These patients underwent high-dose-rate (HDR interstitial BT with free-hand placement of metal needles guided by real-time 3D-CT. Six Gy in 6 fractions were prescribed for the high-risk clinical target volume (HR-CTV. D 90 and D 100 for HR-CTV of BT, and the cumulative D 2cc for the bladder, rectum, and sigmoid, including previous EBRT and present BT were analyzed. Treatment-related complications and 3-month tumor-response rates were investigated. Results: The mean D 90 value for HR-CTV was 52.5 ± 3.3 Gy. The cumulative D 2cc for the bladder, rectum, and sigmoid were 85.6 ± 5.8, 71.6 ± 6.4, and 69.6 ± 5.9 Gy, respectively. The mean number of needles was 6.1 ± 1.5, with an average depth of 3.5 ± 0.9 cm for each application. Interstitial BT was associated with minor complications and passable tumor-response rate. Conclusions : Interstitial BT guided by real-time 3D-CT for recurrent cervical cancer results in good dose-volume histogram (DVH parameters. The current technique may be clinically feasible. However, long-term clinical outcomes should be further investigated.

  5. Breast computed tomography with the PICASSO detector: A feasibility study

    Science.gov (United States)

    Rigon, Luigi; Tapete, Federica; Dreossi, Diego; Arfelli, Fulvia; Bergamaschi, Anna; Chen, Rong-Chang; Longo, Renata; Menk, Ralf-Hendrik; Schmitt, Bernd; Vallazza, Erik; Castelli, Edoardo

    2011-02-01

    The SYRMEP (Synchrotron Radiation for Medical Physics) collaboration has performed, for the first time in the world, a clinical program of mammography with synchrotron radiation. This program provided excellent results, although utilizing a commercial screen-film system as a detector. The PICASSO (Phase Imaging for Clinical Application with Silicon detector and Synchrotron radiation) project has developed a detector prototype capable of fully exploiting the peculiar characteristics of the synchrotron source, utilizing silicon microstrip sensors illuminated in the edge-on geometry and operated in single-photon counting. In this paper the potential of the PICASSO detector in breast computed tomography was evaluated by means of custom phantoms. Very encouraging results have been obtained with severe dose constrains as far as both spatial and contrast resolution are concerned. Moreover, the capability of detecting phase contrast effects was demonstrated, albeit with a higher delivered dose.

  6. Computed tomography dose optimisation in cystic fibrosis: A review.

    LENUS (Irish Health Repository)

    Ferris, Helena

    2016-04-28

    Cystic fibrosis (CF) is the most common autosomal recessive disease of the Caucasian population worldwide, with respiratory disease remaining the most relevant source of morbidity and mortality. Computed tomography (CT) is frequently used for monitoring disease complications and progression. Over the last fifteen years there has been a six-fold increase in the use of CT, which has lead to a growing concern in relation to cumulative radiation exposure. The challenge to the medical profession is to identify dose reduction strategies that meet acceptable image quality, but fulfil the requirements of a diagnostic quality CT. Dose-optimisation, particularly in CT, is essential as it reduces the chances of patients receiving cumulative radiation doses in excess of 100 mSv, a dose deemed significant by the United Nations Scientific Committee on the Effects of Atomic Radiation. This review article explores the current trends in imaging in CF with particular emphasis on new developments in dose optimisation.

  7. Clinical applications of cone beam computed tomography in endodontics: A comprehensive review.

    Science.gov (United States)

    Cohenca, Nestor; Shemesh, Hagay

    2015-09-01

    The use of cone beam computed tomography (CBCT) in endodontics has been extensively reported in the literature. Compared with the traditional spiral computed tomography, limited field of view (FOV) CBCT results in a fraction of the effective absorbed dose of radiation. The purpose of this manuscript is to review the application and advantages associated with advanced endodontic problems and complications, while reducing radiation exposure during complex endodontic procedures. The benefits of the added diagnostic information provided by intraoperative CBCT images in select cases justify the risk associated with the limited level of radiation exposure.

  8. Dosimetry in abdominal imaging by 6-slice computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Sonia Isabel [Hospital de Faro, EPE (Portugal); Abrantes, Antonio Fernando; Ribeiro, Luis Pedro; Almeida, Rui Pedro Pereira [University of Algarve (Portugal). School of Health. Dept. of Radiology

    2012-11-15

    Objective: To determine the effective dose in abdominal computed tomography imaging and to study the influence of patients' characteristics on the received dose. Materials and Methods: Dose values measurements were performed with an ionization chamber on phantoms to check the agreement between dose values and those presented by the computed tomography apparatus, besides their compliance with the recommended reference dose levels. Later, values of dose received by physically able patients submitted to abdominal computed tomography (n = 100) were measured and correlated with their anthropometric characteristics. Finally, the dose to organs was simulated with the Monte Carlo method using the CT-Expo V 1.5 software, and the effect of automatic exposure control on such examinations. Results: The main characteristics directly influencing the dose include the patients' body mass, abdominal perimeter and body mass index, whose correlation is linear and positive. Conclusion: The radiation dose received from abdominal CT scans depends on some patient's characteristics, and it is important to adjust the acquisition parameters to their dimensions (author)

  9. Computed tomography to quantify tooth abrasion

    Science.gov (United States)

    Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

    2010-09-01

    Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

  10. Concrescence: assessment of case by periapical radiography, cone beam computed tomography and micro-computed tomography.

    Science.gov (United States)

    Neves, Frederico Sampaio; Rovaris, Karla; Oliveira, Matheus Lima; Novaes, Pedro Duarte; de Freitas, Deborah Queiroz

    2014-04-01

    The aim of this article was to describe imaging aspects of concrescence analyzed by three imaging modalities. A second molar joined together with a third molar was imaged using digital periapical radiography, cone beam computed tomography (CBCT) and micro-computed tomography (Micro-CT). On periapical radiograph, the mesial root of the third molar is superimposed on the distal root of the second molar. On CBCT images, a large cementum union between bulbous roots was detected, confirming the diagnosis of concrescence. On micro-CT images, the cementum union appeared limited to the apical third of the roots. In conclusion, both computed tomography modalities allowed for the diagnosis of concrescence. However, only micro-CT provided the real extension of the cementum union.

  11. Volumetric and dosimetric assessment by cone-beam computed tomography scans in head and neck radiation therapy: a monitoring in four phases of treatment.

    Science.gov (United States)

    Cozzolino, M; Fiorentino, A; Oliviero, C; Pedicini, P; Clemente, S; Califano, G; Caivano, R; Chiumento, C; Fusco, V

    2014-08-01

    Due to the anatomical changes frequently occurring during the course of head and neck (H&N) cancer radiotherapy, the dose distribution, which was actually delivered to the patient, might significantly differ from that planned. The aim of this paper is to investigate these volumetric changes and the resulting dosimetric implications on organs at risk (OARs) and clinical target volumes (CTVs) by cone beam computed tomography (CBCT) scans throughout the treatment. Ten H&N patients, treated by Intensity Modulated Radiotherapy, were analyzed. CTVs and OARs were delineated on four CBCT, acquired at the 10(th), 15(th), 20(th) and 25(th) treatment session, and then compared with the ones at planning CT. The planned beams were applied to each CBCT to recalculate the dose distribution and the corresponding dose volume histograms were compared with those generated on planning CT. To evaluate the HU discrepancies between the conventional CT and CBCT images we used a Catphan(r) 504, observing a maximum discrepancy of about 30 HU. We evaluated the impact of this HU difference in dose calculation and a not clinically relevant error, within 2.8%, was estimated. No inhomogeneity correction was used. The results showed an increased CTV mean dose (Dmean) of about 3% was found, without significant reduction in volume. Due to the parotids' shrinkage (up to 42%), significant dosimetric increases were observed: ipsilateral gland at 15th CBCT (Dmean by 18%; V30 by 31%); controlateral gland at the 10(th) CBCT (Dmean by 12.2%; V30 by 18.7%). For the larynx, a significant increase of volume was found at the 20th (15.7%) and 25th CBCT (13.3%) but it complied with dose constraint. The differences observed for the spinal cord and mandible maximum doses were not clinically relevant. In conclusion, the dosimetric analysis on CBCT can help clinicians to monitor treatment progress and to evaluate whether and when a new plan is necessary. The main benefit of replanning could be to preserve the

  12. Positron Computed Tomography: Current State, Clinical Results and Future Trends

    Science.gov (United States)

    Schelbert, H. R.; Phelps, M. E.; Kuhl, D. E.

    1980-09-01

    An overview is presented of positron computed tomography: its advantages over single photon emission tomography, its use in metabolic studies of the heart and chemical investigation of the brain, and future trends. (ACR)

  13. Volume of Lytic Vertebral Body Metastatic Disease Quantified Using Computed Tomography-Based Image Segmentation Predicts Fracture Risk After Spine Stereotactic Body Radiation Therapy.

    Science.gov (United States)

    Thibault, Isabelle; Whyne, Cari M; Zhou, Stephanie; Campbell, Mikki; Atenafu, Eshetu G; Myrehaug, Sten; Soliman, Hany; Lee, Young K; Ebrahimi, Hamid; Yee, Albert J M; Sahgal, Arjun

    2017-01-01

    To determine a threshold of vertebral body (VB) osteolytic or osteoblastic tumor involvement that would predict vertebral compression fracture (VCF) risk after stereotactic body radiation therapy (SBRT), using volumetric image-segmentation software. A computational semiautomated skeletal metastasis segmentation process refined in our laboratory was applied to the pretreatment planning CT scan of 100 vertebral segments in 55 patients treated with spine SBRT. Each VB was segmented and the percentage of lytic and/or blastic disease by volume determined. The cumulative incidence of VCF at 3 and 12 months was 14.1% and 17.3%, respectively. The median follow-up was 7.3 months (range, 0.6-67.6 months). In all, 56% of segments were determined lytic, 23% blastic, and 21% mixed, according to clinical radiologic determination. Within these 3 clinical cohorts, the segmentation-determined mean percentages of lytic and blastic tumor were 8.9% and 6.0%, 0.2% and 26.9%, and 3.4% and 15.8% by volume, respectively. On the basis of the entire cohort (n=100), a significant association was observed for the osteolytic percentage measures and the occurrence of VCF (Pconfidence interval 9.4-148.9). On multivariable analysis, ≥11.6% lytic disease (P<.001), baseline VCF (P<.001), and SBRT with ≥20 Gy per fraction (P=.014) were predictive. Pretreatment lytic VB disease volumetric measures, independent of the blastic component, predict for SBRT-induced VCF. Larger-scale trials evaluating our software are planned to validate the results. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Individualized kV selection and tube current reduction in excretory phase computed tomography urography: potential for radiation dose reduction and the contribution of iterative reconstruction to image quality.

    Science.gov (United States)

    Froemming, Adam T; Kawashima, Akira; Takahashi, Naoki; Hartman, Robert P; Nathan, Mark A; Carter, Rickey E; Yu, Lifeng; Leng, Shuai; Kagoshima, Hiroki; McCollough, Cynthia H; Fletcher, Joel G

    2013-01-01

    The objective of this study was to analyze radiation dose reduction and image quality by combining automated kV selection, tube current reduction, and iterative reconstruction. This was a retrospective analysis of the excretory phase of 55 patients with 2 computed tomography urography examinations: automated kV selection with tube current reduction ("low-dose protocol": with filtered back projection vs iterative reconstruction) and routine dose examinations. Image quality was analyzed blindly and in side-by-side analyses, in addition to quantitative measurements. Low-dose protocol median dose change was -40% (-10.7 to +12.9 mGy); 100 kV was autoselected in 44 (80%) of 55 patients (body mass index range, 19-36 kg/m) with mean dose reduction of 42.5%. Whereas up to 19% of low-dose images with filtered back projection were inferior by blinded review (P < 0.001), low-dose iterative reconstruction images were not rated inferior (P = 1.0). The combination of iterative reconstruction, automated kV selection, and tube current reduction results in radiation dose reduction with preserved image quality and diagnostic confidence.

  15. Inter-scan and inter-observer tumour volume delineation variability on cone beam computed tomography in patients treated with stereotactic body radiation therapy for early-stage non-small cell lung cancer.

    Science.gov (United States)

    Hou, Ying; Lee, Stephanie; Agrawal, Vishesh; Romano, John; Baldini, Elizabeth H; Chen, Aileen B; Kozono, David E; Killoran, Joseph H; Wagar, Matthew; Hacker, Fred L; Aerts, Hugo Jwl; Lewis, John H; Mak, Raymond H

    2017-02-01

    Quantification of volume changes on cone beam computed tomography (CBCT) during lung stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC) may provide a useful radiological marker for radiation response and for adaptive treatment planning. This study quantifies inter-scan and inter-observer variability in tumour volume delineation on CBCT. Three clinicians independently contoured the primary gross tumour volume (GTV) manually on CBCTs taken immediately before SBRT treatment (pre) and after the same SBRT treatment (post) for 19 NSCLC patients. Relative volume differences (RVD) were calculated between the pre- and post-CBCTs for a given treatment and between any two of three observers for a given CBCT. Coefficient of variation (CV) was used to quantitatively measure and compare the extent of variability. Inter-observer variability had a significantly higher CV of 0.15 ± 0.13 compared to inter-scan CV of 0.03 ± 0.04 with P volume delineation on CBCT with greatest variability for small tumours (volume change during SBRT treatment for tumours with diameter greater than 2 cm, with larger thresholds needed for smaller tumours. © 2016 The Royal Australian and New Zealand College of Radiologists.

  16. Computed tomography of sacral and presacral lesions

    Energy Technology Data Exchange (ETDEWEB)

    Soye, I.; Levine, E.; Batnitzky, S.; Price, H.I.

    1982-11-01

    Forty-two patients with various sacral and presacral lesions were examined by computed tomography (CT). CT was sensitive in detecting intraosseous neoplasms and presacral soft tissue masses and in seven cases identified lesions not visible on plain films. The total extent of each lesion was readily determined using CT. However, CT is diagnostically nonspecific and differentiation between primary and secondary tumors of the sacrum is generally not possible from the CT appearance alone. CT is also of considerable use in the evaluation of several non-neoplastic conditions of the sacrum, including spinal dystrophism, anterior and internal meningocele and trauma.

  17. Computed Tomography in the Modern Slaughterhouse

    DEFF Research Database (Denmark)

    Mosbech, Thomas Hammershaimb

    of technology. Recently, the use of X-ray computed tomography (CT) coupled with methods from image analysis has been introduced as a powerful means to optimise production, by providing detailed information on the raw materials. This thesis covers two aspects of the application of CT in the modern abattoir...... of the subject-specific X-ray data needed to produce high quality images for accurate measurements. This is very beneficial for the abattoirs, as a reduction in acquired data translates directly into higher speed and a lower cost. The thesis demonstrates the great potential of CT as a technology for improving...

  18. Imaging of Cardiac Valves by Computed Tomography

    OpenAIRE

    Gudrun Feuchtner

    2013-01-01

    This paper describes “how to” examine cardiac valves with computed tomography, the normal, diseased valves, and prosthetic valves. A review of current scientific literature is provided. Firstly, technical basics, “how to” perform and optimize a multislice CT scan and “how to” interpret valves on CT images are outlined. Then, diagnostic imaging of the entire spectrum of specific valvular disease by CT, including prosthetic heart valves, is highlighted. The last part gives a guide “how to” use ...

  19. Enlarged retrorectal space - indication for computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Krestin, G.P.; Steinbrich, W.; Beyer, D.

    1985-03-01

    The reasonable use of computed tomography in the diagnosis of an enlarged retrorectal space was analysed in 92 cases. CT is useful in differentiation of a pathologically enlarged retrorectal space without mucosal lesions of the rectum. It enables the separation between tumorous masses, proliferation of connective tissue (in retrorectal fibrosis or inflammatory disease) and pelvic lipomatosis. If simultaneous mucosal involvement in barium enema or rectoscopy - especially in rectal carcinoma or recurrent carcinoma of the rectum - is found, CT may show the perirectal extension of tumorous masses and thus help to clarify local operability.

  20. Inter laboratory comparison on Industrial Computed Tomography

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; De Chiffre, Leonardo

    An interlaboratory comparison on industrial X-ray Computed Tomography (CT) was organized by the Centre for Geometrical Metrology (CGM), Department of Mechanical Engineering, Technical University of Denmark (DTU) and carried out within the project “Centre for Industrial Application of CT scanning...... - CIA-CT”. In the comparison, 27 laboratories from 8 countries were involved, and CT scanned two items selected among common industrial parts: a polymer part and a metal part. Altogether, 27 sets of items were circulated in parallel to the participants. Different measurands are considered, encompassing...

  1. Analysis of airways in computed tomography

    DEFF Research Database (Denmark)

    Petersen, Jens

    Chronic Obstructive Pulmonary Disease (COPD) is major cause of death and disability world-wide. It affects lung function through destruction of lung tissue known as emphysema and inflammation of airways, leading to thickened airway walls and narrowed airway lumen. Computed Tomography (CT) imaging...... have become the standard with which to assess emphysema extent but airway abnormalities have so far been more challenging to quantify. Automated methods for analysis are indispensable as the visible airway tree in a CT scan can include several hundreds of individual branches. However, automation...

  2. Investigation of measuring strategies in computed tomography

    DEFF Research Database (Denmark)

    Müller, Pavel; Hiller, Jochen; Cantatore, Angela

    2011-01-01

    Computed tomography has entered the industrial world in 1980’s as a technique for non-destructive testing and has nowadays become a revolutionary tool for dimensional metrology, suitable for actual/nominal comparison and verification of geometrical and dimensional tolerances. This paper evaluates...... and VGStudio MAX. Bias values of all measurands for the toggle were in the same range for all the three software and uncertainties were in the range of calibration uncertainties. Uncertainties connected with measurement of the distance between two surfaces on the inner flange of the pipe connector from CT...

  3. Computed tomography appearances of sclerosing encapsulating peritonitis

    Energy Technology Data Exchange (ETDEWEB)

    George, C. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom)]. E-mail: cheriangeorge@hotmail.com; Al-Zwae, K. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom); Nair, S. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom); Cast, J.E.I. [Department of Radiology, Hull Royal Infirmary, Hull (United Kingdom)

    2007-08-15

    Sclerosing encapsulating peritonitis (SEP) is a serious complication of peritoneal dialysis (PD) characterized by thickened peritoneal membranes, which lead to decreased ultra-filtration and intestinal obstruction. Its early clinical features are nonspecific, and it is often diagnosed late following laparotomy and peritoneal biopsy, when the patient develops small bowel obstruction, which can be a life-threatening complication. However, this is changing with increasing awareness of computed tomography (CT) findings in SEP. CT can yield an early, non-invasive diagnosis that may improve patient outcome. We present a review of the CT appearances of SEP.

  4. Cardiac computed tomography in current cardiology guidelines.

    Science.gov (United States)

    Al-Mallah, Mouaz H; Aljizeeri, Ahmed; Villines, Todd C; Srichai, Monvadi B; Alsaileek, Ahmed

    2015-01-01

    Practice guidelines issued by professional societies significantly impact cardiology practice throughout the world. They increasingly incorporate cardiac CT imaging. This review systematically analyzes clinical practice guidelines issued by the American College of Cardiology Foundation (ACCF)/American Heart Association (AHA) and the European Society of Cardiology (ESC) as well as the multi-societal appropriateness criteria in their latest versions as of September 1st, 2015, in order to identify the extent to which they include recommendations to use cardiac CT in specific clinical situations. Copyright © 2015 Society of Cardiovascular Computed Tomography. All rights reserved.

  5. Limited short-term effect of palliative radiation therapy on quantitative computed tomography-derived bone mineral density in femora with metastases

    NARCIS (Netherlands)

    Eggermont, F.E.; Derikx, L.C.; Verdonschot, N.J.; Hannink, G.J.; Kaatee, R.; Tanck, E.J.; Linden, Y.M. van der

    2017-01-01

    PURPOSE: The aim of this study was to determine the effect of single fraction (SF) and multiple fraction (MF) radiation therapy (RT) on bone mineral density (BMD) in patients with cancer and bone metastases in the proximal femur. We studied this effect in the radiation field and within metastatic

  6. Recent Developments in Computed Tomography for Urolithiasis: Diagnosis and Characterization

    Directory of Open Access Journals (Sweden)

    P. D. Mc Laughlin

    2012-01-01

    Full Text Available Objective. To critically evaluate the current literature in an effort to establish the current role of radiologic imaging, advances in computed tomography (CT and standard film radiography in the diagnosis, and characterization of urinary tract calculi. Conclusion. CT has a valuable role when utilized prudently during surveillance of patients following endourological therapy. In this paper, we outline the basic principles relating to the effects of exposure to ionizing radiation as a result of CT scanning. We discuss the current developments in low-dose CT technology, which have resulted in significant reductions in CT radiation doses (to approximately one-third of what they were a decade ago while preserving image quality. Finally, we will discuss an important recent development now commercially available on the latest generation of CT scanners, namely, dual energy imaging, which is showing promise in urinary tract imaging as a means of characterizing the composition of urinary tract calculi.

  7. [A dynamic phantom for computer tomography].

    Science.gov (United States)

    Nüsslin, F

    1981-06-01

    A phantom is described which has been developed for investigating factors depending on the scanner itself and on the scanned object which potentially influence the kind and the extent of motion artefacts on the CT-image. Additionally, the phantom may be applied to qualify assurance measurements in computer tomography. A cylindrical insert mounted on a motor driven axis is fitted centrally in a cylindrical block machined from lucite. Two interchangeable inserts are available, one containing test objects made of various materials, and another one containing small vessels which can be filled with test solutions. The insert positioned in the phantom can rotate either continuously or with the direction of motion being altered periodically. Speed, frequency and arc can be varied within wide limits. Examples demonstrating the static and the dynamic mode of the phantom are shown. By means of the dynamic phantom it is quite easy to directly determine the scan-time of a Computer tomograph.

  8. Evaluation of Sinonasal Diseases by Computed Tomography.

    Science.gov (United States)

    Kandukuri, Rashmi; Phatak, Suresh

    2016-11-01

    Computed Tomography (CT) plays an important diagnostic role in patients with sinonasal diseases and determines the treatment. The CT images clearly show fine structural architecture of bony anatomy thereby determining various anatomical variation, extent of disease and characterization of various inflammatory, benign and malignant sinonasal diseases. To evaluate sensitivity and specificity of CT in diagnosis of sinonasal diseases and to characterise the benign and malignant lesions with the help of various CT parameters. Also, to correlate findings of CT with histo-pathological and diagnostic nasal endoscopy/ Functional Endoscopic Sinus Surgery (FESS) findings. In this hospital based prospective study 175 patients with symptomatic sinonasal diseases were evaluated by clinical diagnosis and 16 slice Multi Detector Computed Tomography (MDCT). The details of findings of nasal endoscopy, Functional Endoscopic Sinus Surgery (FESS), histopathological examination and fungal culture were collected in all those cases where those investigations were done. All those findings were correlated with CT findings and statistical analysis was done by using Test statistics (sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and accuracy), Chi-Square test and Z-test for single proportions. Software used in the analysis was SPSS 17.0 version and graph pad prism 6.0 version and p evaluating various congenital, inflammatory, benign and malignant pathologies and associated complications thereby planning the further management of the patient. CT is the best modality of choice for evaluating the bone erosion or destruction. The potential pitfalls to differentiate on CT are fungal sinusitis and dense secretions.

  9. Evaluation of valvular heart diseases with computed tomography.

    Science.gov (United States)

    Tomoda, H; Hoshiai, M; Matsuyama, S

    1982-04-01

    Forty-two patients with valvular heart diseases were studied with a third-generation computed tomographic system. The cardiac chambers (the atria and ventricles) were evaluated semiquantitatively, and valvular calcification was easily detected with computed tomography. Computed tomography was most valuable in revealing left atrial thrombi which were not identified by other diagnostic procedures in some cases.

  10. Evaluation of valvular heart diseases with computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tomoda, H.; Hoshiai, M.; Matsuyama, S. (Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine)

    1982-04-01

    Forty-two patients with valvular heart diseases were studied with a third-generation computed tomographic system. The cardiac chambers (the atria and ventricles) were evaluated semiquantitatively, and valvular calcification was easily detected with computed tomography. Computed tomography was most valuable in revealing left atrial thrombi which were not identified by other diagnostic procedures in some cases.

  11. Study of radiation conditions for obtaining standard beam computed tomography; Estudo das condicoes de radiacao para obtencao do feixe padrao em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Lucio das Chagas de; Peixoto, Jose Guilherme Pereira, E-mail: lucio-andrade@hotmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    In Brazil there is a need to expand the traceability for the calibration of cameras used in dosimetry in CT. Thus, in order to promote the expansion of the radiation conditions RQT, LNMRI disseminate this greatness. These radiation conditions may be characterized in terms of tension in the X-ray tube (PPV), the first half-value layer (1{sup st} HVL) and homogeneity coefficient (CH). The LNMRI achieved satisfactory results within the international specifications suggested by IEC 61267 and TRS 457. (author)

  12. Effect of the forward-projected model-based iterative reconstruction solution algorithm on image quality and radiation dose in pediatric cardiac computed tomography.

    Science.gov (United States)

    Nishiyama, Yukako; Tada, Keiji; Nishiyama, Yuichi; Mori, Hiroshi; Maruyama, Mitsunari; Katsube, Takashi; Yamamoto, Nobuko; Kanayama, Hidekazu; Yamamoto, Yasushi; Kitagaki, Hajime

    2016-11-01

    Some iterative reconstruction algorithms are useful for reducing the radiation dose in pediatric cardiac CT. A new iterative reconstruction algorithm (forward-projected model-based iterative reconstruction solution) has been developed, but its usefulness for radiation dose reduction in pediatric cardiac CT is unknown. To investigate the effect of the new algorithm on CT image quality and on radiation dose in pediatric cardiac CT. We obtained phantom data at six dose levels, as well as pediatric cardiac CT data, and reconstructed CT images using filtered back projection, adaptive iterative dose reduction 3-D (AIDR 3-D) and the new algorithm. We evaluated phantom image quality using physical assessment. Four radiologists performed visual evaluation of cardiac CT image quality. In the phantom study, the new algorithm effectively suppressed noise in the low-dose range and moderately generated modulation transfer function, yielding a higher signal-to-noise ratio compared with filtered back projection or AIDR 3-D. When clinical cardiac CT was performed, images obtained by the new method had less perceived image noise and better tissue contrast at similar resolution compared with AIDR 3-D images. The new algorithm reduced image noise at moderate resolution in low-dose CT scans and improved the perceived quality of cardiac CT images to some extent. This new algorithm might be superior to AIDR 3-D for radiation dose reduction in pediatric cardiac CT.

  13. Limited short-term effect of palliative radiation therapy on quantitative computed tomography-derived bone mineral density in femora with metastases

    Directory of Open Access Journals (Sweden)

    Florieke Eggermont, MSc

    2017-01-01

    Conclusions: Ten weeks after palliative radiation therapy in patients with femoral metastatic lesions, a limited increase in BMD was seen with no beneficial effect of MF over SF RT. BMD in lytic lesions was unchanged but slightly increased in mixed and blastic lesions.

  14. Radiation dose and imaging quality of abdominal computed tomography before and scan protocol adjustment: Single-institution experience in three years

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hwi Young; Choi, Joon Il; Jung, Seung Eun; Rha, Seong Eun; Oh, Nam Soon; Lee, Young Joon; Byun, Jae Young [Dept. of Radiology, Seoul St. Mary' s Hospital, The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of)

    2014-12-15

    To compare radiation dose and image quality of abdominal CT for patients who underwent repeated CT examinations before and after adjustment of scan protocol. We compared radiation dose and image quality of repeated abdominal CT scans (at three-year-interval) of 50 patients with chronic liver disease, 50 patients with early gastric cancer, and 50 patients with uterine cancer. To reduce radiation dose, we optimized CT protocols by omitting unnecessary pre-contrast phase, reducing kVp, and setting higher noise index. Data of dose reports were collected. Objective image quality was evaluated for noise level, signal to noise ratio (SNR), and contrast noise ratio (CNR). For subjective image quality, we evaluated image noise, contrast, and overall diagnostic acceptability. The mean values of dose length product of 2011 CT scans compared to those of 2008 CT scans were 27.6% to 45.7%. The image noise level, SNR, and CNR were significantly (p < 0.05) worse in 2011 CT scans compared to 2008 CT scans. For subjective image quality, image noise was also significantly (p < 0.05) worse in 2011. However, CNR and diagnostic acceptability showed variable results. No CT scans were considered as unacceptable image.We modified abdominal CT protocols to reduce radiation exposure while trying to maintain diagnostic acceptability.

  15. Radiation exposure to operating staff during rotational flat-panel angiography and C-arm cone beam computed tomography (CT) applications.

    Science.gov (United States)

    Schulz, Boris; Heidenreich, Ralf; Heidenreich, Monika; Eichler, Katrin; Thalhammer, Axel; Naeem, Naguib Nagy Naguib; Vogl, Thomas Josef; Zangos, Stefan

    2012-12-01

    To evaluate the radiation exposure for operating personnel associated with rotational flat-panel angiography and C-arm cone beam CT. Using a dedicated angiography-suite, 2D and 3D examinations of the liver were performed on a phantom to generate scattered radiation. Exposure was measured with a dosimeter at predefined heights (eye, thyroid, breast, gonads and knee) at the physician's location. Analysis included 3D procedures with a field of view (FOV) of 24 cm × 18 cm (8s/rotation, 20s/rotation and 5s/2 rotations), and 47 cm×18 cm (16s/2 rotations) and standard 2D angiography (10s, FOV 24 cm×18 cm). Measurements showed the highest radiation dose at the eye and thyroid level. In comparison to 2D-DSA (3.9 μSv eye-exposure), the 3D procedures caused an increased radiation exposure both in standard FOV (8s/rotation: 28.0 μSv, 20s/rotation: 79.3 μSv, 5s/2 rotations: 32.5 μSv) and large FOV (37.6 μSv). Proportional distributions were measured for the residual heights. With the use of lead glass, irradiation of the eye lens was reduced to 0.2 μSv (2D DSA) and 10.6 μSv (3D technique with 20s/rotation). Rotational flat-panel angiography and C-arm cone beam applications significantly increase radiation exposure to the attending operator in comparison to 2D angiography. Our study indicates that the physician should wear protective devices and leave the examination room when performing 3D examinations. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  16. Computed tomography findings in convergent strabismus fixus

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Michitaka; Iwashige, Hiroyasu; Hayashi, Takao; Maruo, Toshio [Teikyo Univ., Tokyo (Japan). Faculty of Medicine

    1995-08-01

    X-ray computed tomography (CT) of the eyeball and orbit revealed the cause of eye movement disorder in convergent strabismus fixus. The findings suggest that the disease can be diagnosed and treated at an early stage. Twelve cases of progressive esotropia with high myopia and 20 cases with normal visual acuity served as subjects in this study. The CT slice was parallel to the German horizontal plane, and the lens and medial and lateral rectus muscles were scanned. The average axial length of the affected eyes was significantly longer than in normal eyes. In progressive esotropia, the characteristic CT findings are an elongated eyeball, mechanical contact between the eyeball and lateral wall of the orbit, and a downward displacement of the lateral rectus muscle. Thus, it is reasonable to conclude that eye movement disorder in convergent strabismus fixus results from weakness of the lateral rectus muscle which has been displaced downward due to compression of the eyeball against the orbital wall. (author).

  17. Computed tomography through the hip joint

    Energy Technology Data Exchange (ETDEWEB)

    Dihlmann, W.

    1981-09-01

    Computed tomography through the hip joint should be used only after conventional radiographs (at least a.p. views). It may provide information that is diagnostic or helpful, e.g. in bacterial infections, trauma of praearthrotic states. Indications for surgery may be obtained in the presence of inflammatory-rheumatic and degenerative hip disease, arthritic deformities and trauma, and the type of suitable operation may be indicated. The obturator internus muscle, which can be seen medial to the acetabulum on the scan, is an important diagnostic indicator where there is trauma or bacterial infection of the hip joint. The capsule of the hip joint can be visualized directly. Slice thickness of 6 mm, or less is necessary.

  18. Single-energy pediatric chest computed tomography with spectral filtration at 100 kVp: effects on radiation parameters and image quality.

    Science.gov (United States)

    Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Kaup, Moritz; Beeres, Martin; Vogl, Thomas J; Scholtz, Jan-Erik

    2017-06-01

    Most of the applied radiation dose at CT is in the lower photon energy range, which is of limited diagnostic importance. To investigate image quality and effects on radiation parameters of 100-kVp spectral filtration single-energy chest CT using a tin-filter at third-generation dual-source CT in comparison to standard 100-kVp chest CT. Thirty-three children referred for a non-contrast chest CT performed on a third-generation dual-source CT scanner were examined at 100 kVp with a dedicated tin filter with a tube current-time product resulting in standard protocol dose. We compared resulting images with images from children examined using standard single-source chest CT at 100 kVp. We assessed objective and subjective image quality and compared radiation dose parameters. Radiation dose was comparable for children 5 years old and younger, and it was moderately decreased for older children when using spectral filtration (P=0.006). Effective tube current increased significantly (P=0.0001) with spectral filtration, up to a factor of 10. Signal-to-noise ratio and image noise were similar for both examination techniques (P≥0.06). Subjective image quality showed no significant differences (P≥0.2). Using 100-kVp spectral filtration chest CT in children by means of a tube-based tin-filter on a third-generation dual-source CT scanner increases effective tube current up to a factor of 10 to provide similar image quality at equivalent dose compared to standard single-source CT without spectral filtration.

  19. Single-energy pediatric chest computed tomography with spectral filtration at 100 kVp: effects on radiation parameters and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Kaup, Moritz; Beeres, Martin; Vogl, Thomas J.; Scholtz, Jan-Erik [Goethe University of Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany)

    2017-06-15

    Most of the applied radiation dose at CT is in the lower photon energy range, which is of limited diagnostic importance. To investigate image quality and effects on radiation parameters of 100-kVp spectral filtration single-energy chest CT using a tin-filter at third-generation dual-source CT in comparison to standard 100-kVp chest CT. Thirty-three children referred for a non-contrast chest CT performed on a third-generation dual-source CT scanner were examined at 100 kVp with a dedicated tin filter with a tube current-time product resulting in standard protocol dose. We compared resulting images with images from children examined using standard single-source chest CT at 100 kVp. We assessed objective and subjective image quality and compared radiation dose parameters. Radiation dose was comparable for children 5 years old and younger, and it was moderately decreased for older children when using spectral filtration (P=0.006). Effective tube current increased significantly (P=0.0001) with spectral filtration, up to a factor of 10. Signal-to-noise ratio and image noise were similar for both examination techniques (P≥0.06). Subjective image quality showed no significant differences (P≥0.2). Using 100-kVp spectral filtration chest CT in children by means of a tube-based tin-filter on a third-generation dual-source CT scanner increases effective tube current up to a factor of 10 to provide similar image quality at equivalent dose compared to standard single-source CT without spectral filtration. (orig.)

  20. Positron emission tomography/computed tomography scanning for ...

    African Journals Online (AJOL)

    making positron emission tomography (PET) an attractive alternative for ... 1Department of Surgery, Nelson R Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, ..... This emphasises the benefit of this hybrid.

  1. Error corrections for quantitative thermal neutron computed tomography

    Science.gov (United States)

    Shi, Liang

    A state-of-the art, two mirror reflection, combination of a Li-6 scintillation screen and a cooled CCD camera high spatial resolution neutron radioscopy imaging system was designed and developed in the RSEC at Penn State. Radiation shielding was applied to the imaging system to achieve a higher spatial resolution. Modulation Transfer Function (MTF) analysis shows that a spatial resolution of 116 microns was achieved. The imaging system was successfully applied for diagnostic measurements of hydrogen fuel cells. A quantitative neutron computed tomography NCT model was developed which confirmed the fundamental computed tomography theory. The model justified the partial volume neutron computed tomography water/ice mass evaluation technique which was designed and tested by Heller. The evaluation results of the water/ice mass using the NCT method was very close to the theoretical value. Sample and background neutron scattering effects were considered as one of the errors that influenced the accuracy of the quantitative measurement using the NCT method. The neutron scattering effect induced cupping artifacts that also contributed to the error in the measurement of water/ice mass using NCT. One method was developed to reduce the cupping artifacts in the reconstruction slice of the water/ice column. The geometric unsharpness, Ug, was demonstrated as the predominant source of error for the accuracy of the 3-D water/ice mass evaluation technique. A unique method was established to reduce the divergence neutron beam associated geometric unsharpness Ug. Compared to the de-convolution algorithm used in de-blurring the image projection, the method has the advantage of minimizing the unsharpness while keeping the degree of cupping through the water column the same. For the 3-D water/ice mass evaluation purpose, this method is a better choice for the water quantification technique error correction.

  2. Computed Tomography in Management of Patients with Non-Localizing Headache

    Directory of Open Access Journals (Sweden)

    Khalsa Al-Nabhani

    2014-01-01

    Full Text Available Objective: To assess the usefulness of a computed tomography scan in patients with non-localized headache. Methods: One-hundred and forty-two patients with non-localized headache were included in a retrospective study after reviewing the medical records of 896 patients at the Radiology Department, Sultan Qaboos University Hospital. Patients with neurological deficits, head injury, previous intracranial intervention, or malignancy were excluded. Radiological findings of all patients were reviewed and results were divided into 3 groups: 1 no intracranial abnormality; 2 with clinically significant intracranial abnormality; and 3 positive without clinical significance or with extracranial abnormality. All patient history records were reviewed for a period of six months following their initial computed tomography scan to assess their clinical outcomes. The cost of computed tomography examination and patient radiation dose were calculated. Results: Of the 142 patients, 64% were females and 36% males (7% pediatric with an age range of 4-87 years (mean: 36.2 years. Among the patients, 70% demonstrated negative computed tomography findings (grade 1, only 4% showed clinically significant findings (grade 2, and 26% demonstrated incidental positive findings with no clinical significance (grade 3. The average cost of computed tomography head examination was approximately 60 Omani Riyal ($156. The clinically significant positive cases were fewer than expected. The average estimated radiation dose for these patients was calculated and found to be around 5 times the radiation from computed tomography of the sinuses (approximately 1.84 mSv. Conclusion: Computed tomography head imaging in patients with non-localized headache has a low likelihood for any significant intracranial lesion. Therefore, it is essential to develop local standard operating procedures to promote better utilization of this type of imaging service.

  3. Diagnosis of lumbar disc hernia with computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizumi, Atsuro; Ohira, Nobuhiro; Ojima, Tadashi; Oshida, Midori; Horaguchi, Mitsuru (Tohoku Rosai Hospital, Sendai (Japan))

    1982-07-01

    Results of computed tomography performed on patients with clinically diagnosed hernia were compared with those of myelography and operative findings. This comparative study suggested that computed tomography is quite different from other methods and very useful in diagnosis of hernia. Some cases of hernia were shown, and the characteristics of CT were reviewed.

  4. Evaluation of one year brain Computed Tomography scans at the ...

    African Journals Online (AJOL)

    Background: Advancement in technology has contributed immensely to medical practice. Computed tomography (CT), a yield of advanced technology has revolutionized the practice of neuroscience. Aim: To evaluate the first one year of brain computed tomography scan in the permanent site of University of Port Harcourt ...

  5. Evaluation of dosimetry and image of very low-dose computed tomography attenuation correction for pediatric positron emission tomography/computed tomography: phantom study

    Science.gov (United States)

    Bahn, Y. K.; Park, H. H.; Lee, C. H.; Kim, H. S.; Lyu, K. Y.; Dong, K. R.; Chung, W. K.; Cho, J. H.

    2014-04-01

    In this study, phantom was used to evaluate attenuation correction computed tomography (CT) dose and image in case of pediatric positron emission tomography (PET)/CT scan. Three PET/CT scanners were used along with acryl phantom in the size for infant and ion-chamber dosimeter. The CT image acquisition conditions were changed from 10 to 20, 40, 80, 100 and 160 mA and from 80 to 100, 120 and 140 kVp, which aimed at evaluating penetrate dose and computed tomography dose indexvolume (CTDIvol) value. And NEMA PET Phantom™ was used to obtain PET image under the same CT conditions in order to evaluate each attenuation-corrected PET image based on standard uptake value (SUV) value and signal-to-noise ratio (SNR). In general, the penetrate dose was reduced by around 92% under the minimum CT conditions (80 kVp and 10 mA) with the decrease in CTDIvol value by around 88%, compared with the pediatric abdomen CT conditions (100 kVp and 100 mA). The PET image with its attenuation corrected according to each CT condition showed no change in SUV value and no influence on the SNR. In conclusion, if the minimum dose CT that is properly applied to body of pediatric patient is corrected for attenuation to ensure that the effective dose is reduced by around 90% or more compared with that for adult patient, this will be useful to reduce radiation exposure level.

  6. Virtual computed tomography gastroscopy: a new technique.

    Science.gov (United States)

    Springer, P; Dessl, A; Giacomuzzi, S M; Buchberger, W; Stöger, A; Oberwalder, M; Jaschke, W

    1997-09-01

    The aim of the present study was to establish a suitable method for virtual computed tomography (CT) gastroscopy. Three-millimeter helical CT scans of a pig stomach were obtained after air insufflation and instillation of diluted diatrizoic acid (Gastrografin), and with double contrast. In addition, three patients with gastric tumors were studied after ingestion of an effervescent agent (Duplotrast, 6 g) and intravenous injection of hyoscine butylbromide (Buscopan, 1 ml). Virtual endoscopy images were computed on a Sun Sparc 20 workstation (128 megabytes of random access memory, four gigabytes of hard disk space), using dedicated software (Navigator, General Electric Medical System Company). The endoscopy sequences were compared with real endoscopic examinations and with anatomical specimens. In the cadaver studies, the best results were obtained with plain air insufflation, whereas virtual CT gastroscopy with diluted contrast and with double contrast showed artifacts simulating polyps, erosions, and flat ulcers. Patient studies showed good correlation with the fiberoptic endoscopy findings, although large amounts of retained gastric fluid substantially reduced the quality of the surface reconstruction. These preliminary results show that virtual CT gastroscopy is able to provide insights into the upper gastrointestinal tract similar to those of fiberoptic endoscopy. However, due to the limited spatial resolution of the CT protocol used, as well as inherent image artifacts associated with the Navigator program's reconstruction algorithm, the form of virtual CT gastroscopy studied was not capable of competing with the imaging quality provided by fiberoptic gastroscopy.

  7. Texture classification of lung computed tomography images

    Science.gov (United States)

    Pheng, Hang See; Shamsuddin, Siti M.

    2013-03-01

    Current development of algorithms in computer-aided diagnosis (CAD) scheme is growing rapidly to assist the radiologist in medical image interpretation. Texture analysis of computed tomography (CT) scans is one of important preliminary stage in the computerized detection system and classification for lung cancer. Among different types of images features analysis, Haralick texture with variety of statistical measures has been used widely in image texture description. The extraction of texture feature values is essential to be used by a CAD especially in classification of the normal and abnormal tissue on the cross sectional CT images. This paper aims to compare experimental results using texture extraction and different machine leaning methods in the classification normal and abnormal tissues through lung CT images. The machine learning methods involve in this assessment are Artificial Immune Recognition System (AIRS), Naive Bayes, Decision Tree (J48) and Backpropagation Neural Network. AIRS is found to provide high accuracy (99.2%) and sensitivity (98.0%) in the assessment. For experiments and testing purpose, publicly available datasets in the Reference Image Database to Evaluate Therapy Response (RIDER) are used as study cases.

  8. Computed Tomography in Diagnosis of Admantinoma.

    Science.gov (United States)

    Misra, Akansha; Misra, Deepankar; Rai, Shalu; Panjwani, Sapna; Ranjan, Vikash; Prabhat, Mukul; Bhalla, Kanika; Bhatnagar, Puneet

    2015-05-01

    Admantinoma is second most common benign odontogenic tumor which clinically appears as an aggressive odontogenic tumor, often asymptomatic and slow growing, associated with symptoms such as swelling, dental malocclusion, pain, and paresthesia of the affected area. The radiographic appearance may vary from unilocular to multilocular radiolucencies, imparting a characteristic honey comb, soap bubble appearance or may resemble a caricature of spider. This report highlights the importance of conventional and advanced imaging in the diagnosis of large and invasive lesions. Patient reported with complaint of swelling in jaw, which progressively increased; and was found to be bony hard, both intra- and extraorally. Radiographs revealed large multilocular radiolucency on left body and ramus of mandible with soap bubble pattern and knife edged root resorption. Computed tomographic examination evaluated the extent of the lesion, internal structure, and relation to adjacent structures; further a reconstructed image was obtained to evaluate extent of destruction in three dimensions. Computed tomography has an important role in the diagnosis and treatment planning is imperative as it is superior in revealing the cortical destruction and extension into the neighboring soft tissues than conventional radiography.

  9. Teflon laryngeal granuloma presenting as laryngeal cancer on combined positron emission tomography and computed tomography scanning.

    Science.gov (United States)

    Ondik, M P; Kang, J; Bayerl, M G; Bruno, M; Goldenberg, D

    2009-05-01

    Positron emission tomography with 18F-fluorodeoxyglucose (18FDG) has been increasingly used in the diagnostic investigation of patients with neoplasms of the head and neck. Positron emission tomography and computed tomography have also proven useful for surveillance of thyroid cancers that no longer concentrate radioiodine. However, certain benign or inflammatory lesions can also accumulate 18F-fluorodeoxyglucose and lead to misdiagnosis. We review and discuss the pitfalls of using positron emission tomography and computed tomography for surveillance of thyroid cancer. We present the case of a 48-year-old woman who was diagnosed with a laryngeal neoplasm on integrated positron emission tomography and computed tomography scanning, after a routine ultrasound demonstrated an enlarged thyroid nodule. On physical examination, she had a laryngeal mass overlying an immobile vocal fold. The mass was biopsied and found to harbour a Teflon granuloma. Positron emission tomography positive Teflon granulomas have previously been reported in the nasopharynx and vocal folds, and should be considered in the differential diagnosis of patients who have undergone prior surgery involving Teflon injection. It is important for otolaryngologists and radiologists to recognise potential causes of false positive positron emission tomography and computed tomography findings, including Teflon granulomas.

  10. Radiation Detection Computational Benchmark Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Shaver, Mark W.; Casella, Andrew M.; Wittman, Richard S.; McDonald, Ben S.

    2013-09-24

    Modeling forms an important component of radiation detection development, allowing for testing of new detector designs, evaluation of existing equipment against a wide variety of potential threat sources, and assessing operation performance of radiation detection systems. This can, however, result in large and complex scenarios which are time consuming to model. A variety of approaches to radiation transport modeling exist with complementary strengths and weaknesses for different problems. This variety of approaches, and the development of promising new tools (such as ORNL’s ADVANTG) which combine benefits of multiple approaches, illustrates the need for a means of evaluating or comparing different techniques for radiation detection problems. This report presents a set of 9 benchmark problems for comparing different types of radiation transport calculations, identifying appropriate tools for classes of problems, and testing and guiding the development of new methods. The benchmarks were drawn primarily from existing or previous calculations with a preference for scenarios which include experimental data, or otherwise have results with a high level of confidence, are non-sensitive, and represent problem sets of interest to NA-22. From a technical perspective, the benchmarks were chosen to span a range of difficulty and to include gamma transport, neutron transport, or both and represent different important physical processes and a range of sensitivity to angular or energy fidelity. Following benchmark identification, existing information about geometry, measurements, and previous calculations were assembled. Monte Carlo results (MCNP decks) were reviewed or created and re-run in order to attain accurate computational times and to verify agreement with experimental data, when present. Benchmark information was then conveyed to ORNL in order to guide testing and development of hybrid calculations. The results of those ADVANTG calculations were then sent to PNNL for

  11. Survey of patient dose in computed tomography in Syria 2009.

    Science.gov (United States)

    Kharita, M H; Khazzam, S

    2010-09-01

    The radiation doses to patient in computed tomography (CT) in Syria have been investigated and compared with similar studies in different countries. This work surveyed 30 CT scanners from six different manufacturers distributed all over Syria. Some of the results in this paper were part of a project launched by the International Atomic Energy Agency in different regions of the world covering Asia, Africa and Eastern Europe. The dose quantities covered are CT dose index (CTDI(w)), dose-length product (DLP), effective dose (E) and collective dose. It was found that most CTDI(w) and DLP values were similar to the European reference levels and in line with the results of similar surveys in the world. The results were in good agreement with the UNSCEAR Report 2007. This study concluded a recommendation for national diagnostic reference level for the most common CT protocols in Syria. The results can be used as a base for future optimisation studies in the country.

  12. An easily assembled laboratory exercise in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Mylott, Elliot; Klepetka, Ryan; Dunlap, Justin C; Widenhorn, Ralf, E-mail: ralfw@pdx.edu [Department of Physics, Portland State University, PO Box 751, Portland, OR 97207 (United States)

    2011-09-15

    In this paper, we present a laboratory activity in computed tomography (CT) primarily composed of a photogate and a rotary motion sensor that can be assembled quickly and partially automates data collection and analysis. We use an enclosure made with a light filter that is largely opaque in the visible spectrum but mostly transparent to the near IR light of the photogate (880 nm) to scan objects hidden from the human eye. This experiment effectively conveys how an image is formed during a CT scan and highlights the important physical and imaging concepts behind CT such as electromagnetic radiation, the interaction of light and matter, artefacts and windowing. Like our setup, previous undergraduate level laboratory activities which teach the basics of CT have also utilized light sources rather than x-rays; however, they required a more extensive setup and used devices not always easily found in undergraduate laboratories. Our setup is easily implemented with equipment found in many teaching laboratories.

  13. Cone beam computed tomography: A boon for maxillofacial imaging

    Directory of Open Access Journals (Sweden)

    Sreenivas Rao Ghali

    2017-01-01

    Full Text Available In day to day practice, the radiographic techniques used individually or in combination suffer from some inherent limits of all planar two-dimensional (2D projections such as magnification, distortion, superimposition, and misrepresentation of anatomic structures. The introduction of cone-beam computed tomography (CBCT, specifically dedicated to imaging the maxillofacial region, heralds a major shift from 2D to three-dimensional (3D approach. It provides a complete 3D view of the maxilla, mandible, teeth, and supporting structures with relatively high resolution allowing a more accurate diagnosis, treatment planning and monitoring, and analysis of outcomes than conventional 2D images, along with low radiation exposure to the patient. CBCT has opened up new vistas for the use of 3D imaging as a diagnostic and treatment planning tool in dentistry. This paper provides an overview of the imaging principles, underlying technology, dental applications, and in particular focuses on the emerging role of CBCT in dentistry.

  14. Computed tomography in children with community-acquired pneumonia

    Energy Technology Data Exchange (ETDEWEB)

    Andronikou, Savvas [Bristol Royal Hospital for Children and the University of Bristol, Department of Paediatric Radiology, Bristol (United Kingdom); University of Cape Town, Department of Radiology, Cape Town (South Africa); Goussard, Pierre [Tygerberg Hospital, Stellenbosch University, Department of Paediatrics and Child Health, Cape Town (South Africa); Sorantin, Erich [Medical University Graz, Department of Radiology, Graz (Austria)

    2017-10-15

    Diagnostic imaging plays a significant role in both the diagnosis and treatment of complications of pneumonia in children and chest radiography is the imaging modality of choice. Computed tomography (CT) on the other hand, is not currently a first-line imaging tool for children with suspected uncomplicated community-acquired pneumonia and is largely reserved for when complications of pneumonia are suspected or there is difficulty in differentiating pneumonia from other pathology. This review outlines the situations where CT needs to be considered in children with pneumonia, describes the imaging features of the parenchymal and pleural complications of pneumonia, discusses how CT may have a wider role in developing countries where human immunodeficiency virus (HIV) and tuberculosis are prevalent, makes note of the role of CT scanning for identifying missed foreign body aspiration and, lastly, addresses radiation concerns. (orig.)

  15. Assessment of Coronary Artery Calcium on Low-Dose Coronary Computed Tomography Angiography With Iterative Reconstruction

    NARCIS (Netherlands)

    Braber, Thijs L; Willemink, Martin J; Bohté, Elzemiek H; Mosterd, Arend; Leiner, Tim; Velthuis, Birgitta K

    2016-01-01

    OBJECTIVE: This study aims to evaluate whether coronary calcium scoring (CCS) is also feasible using low-radiation-dose coronary computed tomography angiography (CCTA) in combination with iterative reconstruction. METHODS: Forty-three individuals without known coronary artery disease underwent both

  16. Nationwide survey of radiation exposure during pediatric computed tomography examinations and proposal of age-based diagnostic reference levels for Japan

    Energy Technology Data Exchange (ETDEWEB)

    Takei, Yasutaka [Kanazawa University, Department of Quantum Medical Technology, Division of Health Sciences, Graduate School of Medical Science, Kanazawa, Ishikawa (Japan); Miyazaki, Osamu [National Center for Child Health and Development, Department of Radiology, Tokyo (Japan); Matsubara, Kosuke; Koshida, Kichiro [Kanazawa University, Department of Quantum Medical Technology, Faculty of Health Sciences, Ishikawa (Japan); Shimada, Yoshiya; Akahane, Keiichi [National Institute of Radiological Sciences, Medical Exposure Research Project, Chiba (Japan); Muramatsu, Yoshihisa [National Cancer Center Hospital East, Department of Radiology, Chiba (Japan); Fujii, Keisuke [Nagoya University, Radiological Technology, Graduate School of Medicine, Aichi (Japan); Suzuki, Shoichi [Fujita Health University, Faculty of Radiological Technology, School of Health Sciences, Aichi (Japan)

    2016-02-15

    Diagnostic reference levels (DRLs) have not been established in Japan. To propose DRLs for CT of the head, chest and abdomen for three pediatric age groups. We sent a nationwide questionnaire by post to 339 facilities. Questions focused on pediatric CT technology, exposure parameters, CT protocols, and radiation doses for age groups <1 year, 1-5 years, and 6-10 years. For the three age groups in the 196 facilities that responded, the 75th percentile values of volume CT dose index based on a 16-cm phantom (CTDI{sub vol} 16 [mGy]) for head, chest and abdominal CT were for infants 39.1, 11.1 and 12.0, respectively; for 1-to 5-year-olds 46.9, 14.3 and 16.7, respectively; and for 6-to 10-year-olds 67.7, 15.0 and 17.0, respectively. The corresponding dose-length products (DLP 16 [mGy·cm]) for head, chest and abdominal CT were for infants 526.1, 209.1 and 261.5, respectively; for 1-to 5-year-olds 665.5, 296.0 and 430.8, respectively; and for 6-to 10-year-olds 847.9, 413.0 and 532.2, respectively. The majority of CTDI{sub vol} 16 and DLP 16 values for the head were higher than DRLs reported from other countries. For risk reduction, it is necessary to establish DRLs for pediatric CT in Japan. (orig.)

  17. Detection of left ventricular thrombi by echotomography and computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kanemitsu, H.; Hirata, S.; Inagaki, T.; Ishikawa, K. (Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine)

    1981-09-01

    Left ventricular (LV) thrombi are rarely recognized during life, though they are not infrequent at the post-mortem examination of patients succumbed to valvular disease, acute myocardial infarction, and cardiomyopathy. We presented five cases in which LV thrombi were detected by cross-sectional echocardiography (CSE) and confirmed by computed tomography. The main purpose of this study was to compare the echocardiographic findings of the LV thrombi with the manifestations of the LV thrombi on the computed tomograms, with a hope to augment the clinical utility of CSE in the detection of LV thrombi. CSE was recorded from the apical and four-chamber views in addition to the conventional approach. A computed tomographic whole-body scanner which utilized a continuously rotating gantry and pulsed anode with X-ray radiation collimated to form a thin fan-shaped beam was used. A complete section scan was performed in 3 seconds. Sustained enhancement was obtained with a rapid intravenous infusion of 30% meglumine iothalanate. Most of the LV thrombi showed an abnormal echo with irregular borders and/or a mobile mass echo at the apex by CSE. Computed tomographic findings suggestive of LV thrombi appeared as a defect, which was apparently different in quality from the surrounding myocardium or valvular apparatus. These findings were quite consistent with those of CSE with respect to the number and the location of the LV thrombi.

  18. Cervical Gross Tumor Volume Dose Predicts Local Control Using Magnetic Resonance Imaging/Diffusion-Weighted Imaging—Guided High-Dose-Rate and Positron Emission Tomography/Computed Tomography—Guided Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Dyk, Pawel; Jiang, Naomi; Sun, Baozhou; DeWees, Todd A. [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Fowler, Kathryn J.; Narra, Vamsi [Department of Diagnostic Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Garcia-Ramirez, Jose L.; Schwarz, Julie K. [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Grigsby, Perry W., E-mail: pgrigsby@wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Division of Gynecologic Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Alvin J. Siteman Cancer Center, Washington University School of Medicine, St Louis, Missouri (United States)

    2014-11-15

    Purpose: Magnetic resonance imaging/diffusion weighted-imaging (MRI/DWI)-guided high-dose-rate (HDR) brachytherapy and {sup 18}F-fluorodeoxyglucose (FDG) — positron emission tomography/computed tomography (PET/CT)-guided intensity modulated radiation therapy (IMRT) for the definitive treatment of cervical cancer is a novel treatment technique. The purpose of this study was to report our analysis of dose-volume parameters predicting gross tumor volume (GTV) control. Methods and Materials: We analyzed the records of 134 patients with International Federation of Gynecology and Obstetrics stages IB1-IVB cervical cancer treated with combined MRI-guided HDR and IMRT from July 2009 to July 2011. IMRT was targeted to the metabolic tumor volume and lymph nodes by use of FDG-PET/CT simulation. The GTV for each HDR fraction was delineated by use of T2-weighted or apparent diffusion coefficient maps from diffusion-weighted sequences. The D100, D90, and Dmean delivered to the GTV from HDR and IMRT were summed to EQD2. Results: One hundred twenty-five patients received all irradiation treatment as planned, and 9 did not complete treatment. All 134 patients are included in this analysis. Treatment failure in the cervix occurred in 24 patients (18.0%). Patients with cervix failures had a lower D100, D90, and Dmean than those who did not experience failure in the cervix. The respective doses to the GTV were 41, 58, and 136 Gy for failures compared with 67, 99, and 236 Gy for those who did not experience failure (P<.001). Probit analysis estimated the minimum D100, D90, and Dmean doses required for ≥90% local control to be 69, 98, and 260 Gy (P<.001). Conclusions: Total dose delivered to the GTV from combined MRI-guided HDR and PET/CT-guided IMRT is highly correlated with local tumor control. The findings can be directly applied in the clinic for dose adaptation to maximize local control.

  19. Reproducibility in the assessment of acute pancreatitis with computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Freire Filho, Edison de Oliveira; Vieira, Renata La Rocca; Yamada, Andre Fukunishi; Shigueoka, David Carlos; Bekhor, Daniel; Freire, Maxime Figueiredo de Oliveira; Ajzen, Sergio; D' Ippolito, Giuseppe [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. of Imaging Diagnosis]. E-mail: eofilho@ig.com.br; eoffilho@uol.com.br

    2007-11-15

    Objective: To evaluate the reproducibility of unenhanced and contrast-enhanced computed tomography in the assessment of patients with acute pancreatitis. Materials and methods: Fifty-one unenhanced and contrast-enhanced abdominal computed tomography studies of patients with acute pancreatitis were blindly reviewed by two radiologists (observers 1 and 2). The morphological index was separately calculated for unenhanced and contrast-enhanced computed tomography and the disease severity index was established. Intraobserver and interobserver reproducibility of computed tomography was measured by means of the kappa index ({kappa}). Results: Interobserver agreement was {kappa} 0.666, 0.705, 0.648, 0.547 and 0.631, respectively for unenhanced and contrast-enhanced morphological index, presence of pancreatic necrosis, pancreatic necrosis extension, and disease severity index. Intraobserver agreement (observers 1 and 2, respectively) was {kappa} = 0.796 and 0.732 for unenhanced morphological index; {kappa} 0.725 and 0.802 for contrast- enhanced morphological index; {kappa} = 0.674 and 0.849 for presence of pancreatic necrosis; {kappa} = 0.606 and 0.770 for pancreatic necrosis extension; and {kappa} = 0.801 and 0.687 for disease severity index at computed tomography. Conclusion: Computed tomography for determination of morphological index and disease severity index in the staging of acute pancreatitis is a quite reproducible method. The absence of contrast- enhancement does not affect the computed tomography morphological index reproducibility. (author)

  20. Computer tomography-aided ventriculography and cisternography

    Energy Technology Data Exchange (ETDEWEB)

    Cernoch, Z.; Sercl, M.; Heger, L.; Parizek, J. (Karlova Univ., Hradec Kralove (Czechoslovakia). Lekarska Fakulta)

    1983-01-28

    Computer tomography was used in 42 patients for the exploration of ventricular and subarachnoidal spaces following intraventricular, lumbar or suboccipital injections of 3 to 5 ml Amipaque using the kind of manoeuvre to permit optimum filling of the region concerned. This type of CT ventriculo- or cisternography is a significant supplement to plain CT examination particularly because it supplies data on the causes of CSF passage blocks. Thus, in two female patients it proved possible to localize cysts in the 3rd ventricle, the density of which was no different from that of CSF. As regards benign stenoses of the aqueduct, it is likely to yield less information than conventional specific ventriculography. On the other hand, the technique gives perfect visualization of all possible communications between pathological intracranial cavities and the ventricular system. CT cisternography proved useful for the identification of small-size isodense growths in the region of the sella turcica, and brought convincing evidence of the causes of profuse liquorrhea by demonstrating the presence of nasal meningocele. It was also found helpful in the analysis of the craniocervical region, otherwise difficult to survey.

  1. Development of quantitative computed tomography lung protocols.

    Science.gov (United States)

    Newell, John D; Sieren, Jered; Hoffman, Eric A

    2013-09-01

    The purpose of this review article is to review the process of developing optimal computed tomography (CT) protocols for quantitative lung CT (QCT). In this review, we discuss the following important topics: QCT-derived metrics of lung disease; QCT scanning protocols; quality control; and QCT image processing software. We will briefly discuss several QCT-derived metrics of lung disease that have been developed for the assessment of emphysema, small airway disease, and large airway disease. The CT scanning protocol is one of the most important elements in a successful QCT. We will provide a detailed description of the current move toward optimizing the QCT protocol for the assessment of chronic obstructive pulmonary disorder and asthma. Quality control of CT images is also a very important part of the QCT process. We will discuss why it is necessary to use CT scanner test objects (phantoms) to provide frequent periodic checks on the CT scanner calibration to ensure precise and accurate CT numbers. We will discuss the use of QCT image processing software to segment the lung and extract the desired QCT metrics of lung disease. We will discuss the practical issues of using this software. The data obtained from the image processing software are then combined with those from other clinical examinations, health status questionnaires, pulmonary physiology, and genomics to increase our understanding of obstructive lung disease and improve our ability to design new therapies for these diseases.

  2. Computed tomography of the mediastinal tumor

    Energy Technology Data Exchange (ETDEWEB)

    Tohyama, Junko; Kono, Michio; Tauchi, Taneyasu; Mizutani, Masako; Mizutani, Hirokazu

    1984-12-01

    Forty-one cases of mediastinal tumor examined by computed tomography were reviewed. CT findings of the mediastinal malignancy were as follows: 1) inhomogeneous density on contrast CT, 2) equivocaton of fat plane surrounding the tumor, 3) irregular margin. Benign teratoma had smooth margin and included fat or calcification density. Mediastinal seminoma was observed as a lobulated mass with no calcification on CT. These findings were similar to the patterns of malignant thymoma or lymphoma. Consequently, it was very difficult to differentiate between malignant thymoma and malignant lymphoma by CT. According to our data, malignant thymoma tended to expand to only one side of the anterior mediastinum and to invade the anterior chest wall. On the other hand, malignant lymphoma of anterior medistinal type expanded into the trachea and the superior vena cava. In patients with sarcoidosis, the enlargement of bilateral hilar lymph nodes was commonly observed, on the contrary, unilateral hilar lymph nodes enlargement was recognized in some cases of malignant lymphoma. (author).

  3. Computed tomography of lipomatous and myxoid tumors

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, S.; Markhede, G.; Berlin, O.

    Thirty-two lipomatous and myxoid tumors were examined by computed tomography (CT). An attempt was made to correlate the radiographic appearance of the tumor to different histologic types of these tumors. It was found that a well delineated lipomatous lesion with uniform radiographic density, an attenuation value below -73 Hounsfield units (HU) and absence of contrast enhancement can be considered strongly suggestive of a benign lipoma. Atypical lipomas, myxoma and well differentiated liposarcomas have good delineation against the surrounding tissue with no peripheral hypervascularity in the majority of cases. The attenuation values varied between -83 and +38 HU. Liposarcomas of myxoid type, mixed myxoid and round-cell type, round-cell type, and pleomorphic type were all poorly delineated with attenuation values between +12 and +38 HU and with varying contrast enhancement. Thus CT can be considered to play an important role in the preoperative evaluation of lipomatous and myxoid tumours of the soft tissues. Besides valuable topographic information CT helps, to some extent, to differentiate between various types of lipomatous tumors.

  4. Computed Tomography Following Body Stuffing Heroin

    Directory of Open Access Journals (Sweden)

    Sean P. Nordt

    2015-12-01

    Full Text Available A 37-year-old male presented to the emergency department (ED in police custody for “medical clearance” before being taken to jail. The patient was approached by police officers for suspicion of selling illicit drugs. When approached by police he ran away and was witnessed to swallow several small plastic baggies suspected to contain heroin. He was apprehended and brought to the ED. On arrival, he was asymptomatic with a blood pressure 144/83mmHg, heart rate 67bpm, respiratory rate of 19bpm, oxygen saturation of 99% on room air and afebrile. A Glasgow coma score was 15 and he was alert and oriented to person, place and time. Patient had a negative review of systems. On physical examination pupils were 4mm and reactive to light, lungs clear to auscultation and had normal respiratory rate with normal cardiovascular exam. Abdomen was soft, non-tender and non-distended with present bowel sounds. The patient admitted to ingesting approximately 20 packets of heroin to avoid being charged with possession. The patient declined activated charcoal and whole bowel irrigation (WBI with polyethylene glycol-electrolyte solution (PEG-ELS. The patient declined a urine toxicology immunoassay screen. A computed tomography (CT of his abdomen with contrast was obtained and read as normal except for a cluster of foreign bodies within the distal stomach likely contained within a plastic bag.

  5. Cone beam computed tomography in veterinary dentistry.

    Science.gov (United States)

    Van Thielen, Bert; Siguenza, Francis; Hassan, Bassam

    2012-01-01

    The purpose of this study was to assess the feasibility of cone beam computed tomography (CBCT) in imaging dogs and cats for diagnostic dental veterinary applications. CBCT scans of heads of six dogs and two cats were made. Dental panoramic and multi-planar reformatted (MPR) para-sagittal reconstructions were created using specialized software. Image quality and visibility of anatomical landmarks were subjectively assessed by two observers. Good image quality was obtained for the MPR para-sagittal reconstructions through multiple teeth. The image quality of the panoramic reconstructions of dogs was moderate while the panoramic reconstructions of cats were poor since the images were associated with an increased noise level. Segmental panoramic reconstructions of the mouth seem to be useful for studying the dental anatomy especially in dogs. The results of this study using human dental CBCT technology demonstrate the potential of this scanning technology in veterinary medicine. Unfortunately, the moderate image quality obtained with the CBCT technique reported here seems to be inferior to the diagnostic image quality obtained from 2-dimensional dental radiographs. Further research is required to optimize scanning and reconstruction protocols for veterinary applications.

  6. Computed Tomography Findings of Mandibular Nutrient Canals.

    Science.gov (United States)

    Kawashima, Yusuke; Sekiya, Kotaro; Sasaki, Yusuke; Tsukioka, Tsuneyuki; Muramatsu, Teruaki; Kaneda, Takashi

    2015-08-01

    The purpose of this study was to assess computed tomography (CT) findings of mandibular nutrient canals using CT images. We retrospectively analyzed the mandibular CT images of 194 consecutive patients. For image analysis such as canal prevalence, location, number, size, shape, and the CT value of nutrient foramina were determined using CT axial images of 0.5 and 3 mm slice thickness. We revealed that the nutrient canals were seen 94.3% in the mandible, mostly seen in the anterior region. By location, nutrient canals were particularly seen between the central and lateral incisors. The mean number of nutrient canals was 2.7. The mean diameter of the nutrient foramen between the central and lateral incisors was 1.0 mm. In about 80% of the cases, foramina between the central and lateral incisors were ovoid. The mean CT value for the nutrient foramina between the central and lateral incisors was 411 HU. Mandibular nutrient canals were ovoid shape, and the mean CT value was 411 HU. By preoperative knowledge of the position and anatomy of the mandibular nutrient canals, complications such as injury to the nutrient canals can be avoided.

  7. Coordinate Metrology by Traceable Computed Tomography

    DEFF Research Database (Denmark)

    Müller, Pavel

    X-ray computed tomography (CT) is a measuring technique which has become an important technology in the production environment over the last years. Due to a number of advantages of CT compared to, e.g., coordinate measuring machines (CMMs), CT has been recently spread in the field of manufacturin...... was documented on a metallic as well as on a plastic part and resulted in comparable observations. The last mentioned method using the ”data base” approach seemed to work well, but its applicability shall be further validated....... is an important factor for decision making about manufactured parts. However, due to many influences in CT, estimation of the uncertainty is a challenge, also because standardized procedures and guidelines are not available yet. In this thesis, several methods for uncertainty estimation were applied in connection...... with a number of industrial components as well as calibrated workpieces. Measurement uncertainty was often used as a parameter for quantification of a selected influence quantity. Uncertainty estimation using the substitution method appeared to be well applicable to CT measurements in production environment...

  8. Gradient computation for VTI acoustic wavefield tomography

    KAUST Repository

    Li, Vladimir

    2016-09-06

    Wavefield tomography can handle complex subsurface geology better than ray-based techniques and, ultimately, provide a higher resolution. Here, we implement forward and adjoint wavefield extrapolation for VTI (transversely isotropic with a vertical symmetry axis) media using a pseudospectral operator that employes a separable approximation of the P-wave dispersion relation. This operator is employed to derive the gradients of the differential semblance optimization (DSO) and modified stack-power objective functions. We also obtain the gradient expressions for the data-domain objective function, which can incorporate borehole information necessary for stable VTI velocity analysis. These gradients are compared to the ones obtained with a space-time finite-difference (FD) scheme for a system of coupled wave equations. Whereas the kernels computed with the two wave-equation operators are similar, the pseudospectral method is not hampered by the imprint of the shear-wave artifact. Numerical examples also show that the modified stack-power objective function produces cleaner gradients than the more conventional DSO operator.

  9. Portable Digital Radiography and Computed Tomography Manual

    Energy Technology Data Exchange (ETDEWEB)

    2007-11-01

    This user manual describes the function and use of the portable digital radiography and computed tomography (DRCT) scanner. The manual gives a general overview of x-ray imaging systems along with a description of the DRCT system. An inventory of the all the system components, organized by shipping container, is also included. In addition, detailed, step-by-step procedures are provided for all of the exercises necessary for a novice user to successfully collect digital radiographs and tomographic images of an object, including instructions on system assembly and detector calibration and system alignment. There is also a short section covering the limited system care and maintenance needs. Descriptions of the included software packages, the DRCT Digital Imager used for system operation, and the DRCT Image Processing Interface used for image viewing and tomographic data reconstruction are given in the appendixes. The appendixes also include a cheat sheet for more experienced users, a listing of known system problems and how to mitigate them, and an inventory check-off sheet suitable for copying and including with the machine for shipment purposes.

  10. Computed tomography of the breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Soo Young; Lee, Yul; Bae, Sang Hoon; Yoon, Jong Sup; Lee, Ki Chu [Hallym University Medical Center, Seoul (Korea, Republic of)

    1985-12-15

    The indication of computed tomography for the breast lesion are 1) Unusually extensive or small breast caused technical difficulties in performing mammograms. 2) Questionable mammographic findings, especially in dense proliferative breast parenchyme. 3) Microcancer. 4) Suspicious regional lymph node enlargement or invasive of the chest wall by breast cancer. The diagnosis of breast CT in breast cancer is based on pathologic anatomic changes and characteristic increase of mean CT No. of lesion following contrast enhancement. Authors analysed CT of the 34 patients who were clinically suspected breast cancer, and compared with mammography. The results are as follows: 1. Pathological diagnosis of 34 cases were 27 cases of breast cancer, 4 cases of fibrocystic disease, 2 cases of fibroadenoma, and 1 case of intraductal papilloma. The diagnostic accuracy of CT in 27 breast cancer was 93% (25 cases) and mammography 71% (19 case). 2. Correct diagnosis of CT in 7 benign breast disease is in 5 cases and mammography in 5 cases. 3. The most important finding of CT in breast cancer is characteristic increase of CT No. of lesion following contrast enhancement (200 ml, 65%): over average 50 HU in 19 cases of 27 breast cancers, 30-50 HU in a 6 cases, 20-30 HU in 2 cases with tumor necrosis. 4. Computed with mammography, other more valuable CT findings of breast cancer are axillary lymph node enlargement and adjacentic pectoral muscle invasion. 5. In conclusion, breast CT is considered as valuable diagnostic tool in evaluation of breast cancer, but not of benign breast disease.

  11. Evaluation of ambient radiation levels in positron emission tomography/computed tomography in microPET/CT laboratory; Avaliacao dos niveis de radiacao ambiental no laboratorio de tomografia por emissao de positrons acoplada a tomografia computadorizada, microPET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Sarmento, Daniele Martins

    2016-11-01

    Micro PET/CT scanner is an essential tool generally used for small animal molecular imaging. Fluorine-18-labeled fluorodeoxyglucose is the most widely used radioisotope in this technique. The present study aimed to evaluate the radiation levels in a micro PET/CT research laboratory of the Radiopharmacy Center at IPEN-CNEN / SP, in order to accomplish both national standards and international recommendations. The radioprotection team has classified the laboratory as supervised area; even this laboratory does not require the adoption of specific measures for protection and safety, should be done regular re-evaluation of the conditions of occupational exposures. Workplace monitoring and individual control assessment were carried out to ensure the radiological protection of all workers directly involved in handling the scanner. Initially, there was conducted a radiometric survey, as well as measurements of the external radiation level in the workplace and its surroundings. To achieve this goal, there were placed nine thermoluminescent dosimeters of CaSO{sub 4}:Dy in preselected locations. Monthly evaluations of the occupationally exposed individuals were carried out through the use of TL dosimeters, ported in the workers' chest. Moreover, whole body measurements were performed every six months. The study period was about two-years which started in April 2014. All tests to evaluate micro PET/CT performance were based on the standard protocol of the equipment in accordance with the standard developed by the Animal PET Standard Task Force. Present study's results demonstrated that the ambient radiation levels (ambient and effective estimated radiation dose), as well as the effective shielding equipment are both adequate. This study emphasizes that it is essential to strictly follow the principles of radioprotection in workplace, whenever researches involve radioactive unsealed sources. (author)

  12. Comparing the image quality of a mobile flat-panel computed tomography and a multidetector computed tomography: a phantom study.

    Science.gov (United States)

    Neubauer, Jakob; Voigt, Johannes M; Lang, Hannah; Scheuer, Carsten; Goerke, Sebastian M; Langer, Mathias; Fiebich, Martin; Kotter, Elmar

    2014-07-01

    The aim of this study was to compare the image quality of a compact mobile flat-panel computed tomography (FPCT) capable of extremity imaging and a multidetector computed tomography (MDCT) in examinations with the same radiation dose. Imaging with the FPCT was performed with default settings. Monte Carlo simulations were used to calculate equivalent dose settings for the 320-row MDCT. Simulations were based on and validated by dose measurements. Homogeneity, geometric distortion, artifacts, accuracy of Hounsfield values, contrast, and spatial resolution were evaluated in different imaging phantoms. Whitney-Mann U Test and Spearman ρ were used for statistical analysis. Homogeneity reached 2.5% for the FPCT and 0.5% for the MDCT. Hounsfield values were more accurate and contrast to noise ratios were higher for the MDCT than the FPCT (P ≤ 0.001). The MDCT depicted more rod inserts than the FPCT did. No significant geometric distortion was detected in either modality. The FPCT was more prone to artifacts around Krischner wires with a diameter of 2 mm (P = 0.05-0.001), whereas the MDCT showed a higher amount of artifacts around wires with a diameter of 0.8 mm (P ≤ 0.001). Spatial resolution was 1 lp/mm (xy), 1.7 lp/mm (z) for the FPCT and 1 lp/mm (xy), less than 1 lp/mm (z) for the MDCT. We compared a mobile FPCT and a 320-row MDCT by using the same radiation dose for scans. We found the spatial resolution to be higher in the FPCT. Hounsfield units were more accurate and homogeneity and contrast resolution were better in MDCT. The MDCT was also less prone to artifacts from thick Kirschner wires but showed comparably more artifacts around thin wires.

  13. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography.

    Science.gov (United States)

    Aparici, Carina Mari; Win, Aung Zaw

    2016-01-01

    We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT) showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results.

  14. Acute Calculous Cholecystitis Missed on Computed Tomography and Ultrasound but Diagnosed with Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

    Directory of Open Access Journals (Sweden)

    Carina Mari Aparici

    2016-01-01

    Full Text Available We present a case of a 69-year-old patient who underwent ascending aortic aneurysm repair with aortic valve replacement. On postsurgical day 12, he developed leukocytosis and low-grade fevers. The chest computed tomography (CT showed a periaortic hematoma which represents a postsurgical change from aortic aneurysm repair, and a small pericardial effusion. The abdominal ultrasound showed cholelithiasis without any sign of cholecystitis. Finally, a fluorodeoxyglucose (FDG-positron emission tomography (PET/CT examination was ordered to find the cause of fever of unknown origin, and it showed increased FDG uptake in the gallbladder wall, with no uptake in the lumen. FDG-PET/CT can diagnose acute cholecystitis in patients with nonspecific clinical symptoms and laboratory results.

  15. Diffuse abnormalities of the trachea: computed tomography findings

    Energy Technology Data Exchange (ETDEWEB)

    Marchiori, Edson [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Radiologia]. E-mail: edmarchiori@gmail.com; Pozes, Aline Serfaty [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Faculdade de Medicina. Dept. de Radiologia; Souza Junior, Arthur Soares [Faculdade de Medicina de Sao Jose do Rio Preto (FAMERP), SP (Brazil). Escola de Medicina. Dept. de Radiologia; Escuissato, Dante Luiz [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Radiologia; Irion, Klaus Loureiro [The Cardiothoracic Centre NHS Trust, Liverpool (United Kingdom); Araujo Neto, Cesar de [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Dept. de Radiologia; Barillo, Jorge Luiz; Zanetti, Glaucia [Faculdade de Medicina de Petropolis (FMP), RJ (Brazil). Dept. de Cirurgia Clinica; Souza, Carolina Althoff [University of Ottawa, Ottawa, ON (Canada)

    2008-01-15

    The aim of this pictorial essay was to present the main computed tomography findings seen in diffuse diseases of the trachea. The diseases studied included amyloidosis, tracheobronchopathia osteochondroplastica, tracheobronchomegaly, laryngotracheobronchial papillomatosis, lymphoma, neurofibromatosis, relapsing polychondritis, Wegener's granulomatosis, tuberculosis, paracoccidioidomycosis, and tracheobronchomalacia. The most common computed tomography finding was thickening of the walls of the trachea, with or without nodules, parietal calcifications, or involvement of the posterior wall. Although computed tomography allows the detection and characterization of diseases of the central airways, and the correlation with clinical data reduces the diagnostic possibilities, bronchoscopy with biopsy remains the most useful procedure for the diagnosis of diffuse lesions of the trachea. (author)

  16. Abdominal alterations in disseminated paracoccidioidomycosis: computed tomography findings

    Energy Technology Data Exchange (ETDEWEB)

    Vermelho, Marli Batista Fernandes; Correia, Ademir Silva; Michailowsky, Tania Cibele de Almeida; Suzart, Elizete Kazumi Kuniyoshi; Ibanes, Aline Santos; Almeida, Lanamar Aparecida; Khoury, Zarifa; Barba, Mario Flores, E-mail: marlivermelho@globo.com [Instituto de Infectologia Emilio Ribas (IIER), Sao Paulo, SP (Brazil)

    2015-03-15

    Objective: to evaluate the incidence and spectrum of abdominal computed tomography imaging findings in patients with paracoccidioidomycosis. Materials and methods: retrospective analysis of abdominal computed tomography images of 26 patients with disseminated paracoccidioidomycosis. Results: abnormal abdominal tomographic findings were observed in 18 patients (69.2%), while no significant finding was observed in the other 8 (30.8%) patients. Conclusion: computed tomography has demonstrated to play a relevant role in the screening and detection of abdominal abnormalities in patients with disseminated paracoccidioidomycosis. (author)

  17. Abdominal alterations in disseminated paracoccidioidomycosis: computed tomography findings*

    Science.gov (United States)

    Vermelho, Marli Batista Fernandes; Correia, Ademir Silva; Michailowsky, Tânia Cibele de Almeida; Suzart, Elizete Kazumi Kuniyoshi; Ibanês, Aline Santos; Almeida, Lanamar Aparecida; Khoury, Zarifa; Barba, Mário Flores

    2015-01-01

    Objective To evaluate the incidence and spectrum of abdominal computed tomography imaging findings in patients with paracoccidioidomycosis. Materials and Methods Retrospective analysis of abdominal computed tomography images of 26 patients with disseminated paracoccidioidomycosis. Results Abnormal abdominal tomographic findings were observed in 18 patients (69.2%), while no significant finding was observed in the other 8 (30.8%) patients. Conclusion Computed tomography has demonstrated to play a relevant role in the screening and detection of abdominal abnormalities in patients with disseminated paracoccidioidomycosis. PMID:25987748

  18. Quantifying the debonding of inclusions through tomography and computational homology.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei-Yang; Johnson, George C. (University of California, Berkeley, Berkeley, CA); Mota, Alejandro; Foulk, James W., III; Jin, Huiqing

    2010-09-01

    This report describes a Laboratory Directed Research and Development (LDRD) project to use of synchrotron-radiation computed tomography (SRCT) data to determine the conditions and mechanisms that lead to void nucleation in rolled alloys. The Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory (LBNL) has provided SRCT data of a few specimens of 7075-T7351 aluminum plate (widely used for aerospace applications) stretched to failure, loaded in directions perpendicular and parallel to the rolling direction. The resolution of SRCT data is 900nm, which allows elucidation of the mechanisms governing void growth and coalescence. This resolution is not fine enough, however, for nucleation. We propose the use statistics and image processing techniques to obtain sub-resolution scale information from these data, and thus determine where in the specimen and when during the loading program nucleation occurs and the mechanisms that lead to it. Quantitative analysis of the tomography data, however, leads to the conclusion that the reconstruction process compromises the information obtained from the scans. Alternate, more powerful reconstruction algorithms are needed to address this problem, but those fall beyond the scope of this project.

  19. Positron emission tomography/computed tomography for optimized colon cancer staging and follow up

    DEFF Research Database (Denmark)

    Engelmann, Bodil Elisabeth; Loft, Annika; Kjær, Andreas

    2014-01-01

    OBJECTIVES: Optimal management of colon cancer (CC) requires detailed assessment of extent of disease. This study prospectively investigates the diagnostic accuracy of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (PET/CT) for staging and detection of recurrence...

  20. Positron emission tomography-computed tomography has a clinical impact for patients with cervical cancer

    DEFF Research Database (Denmark)

    Sandvik, Rikke Mulvad; Jensen, Pernille Tine; Hendel, Helle W

    2011-01-01

    Many studies have found that positron emission tomography-computed tomography (PET-CT) has a high sensitivity and specificity in the identification of metastasis in cervical cancer. Herlev Hospital, Denmark, has been performing PET-CTs in stage I-IV cervical cancer since 1 May 2006. The present...