Direct detector device (DDD) cameras have revolutionized electron cryomicroscopy (cryoEM) with their high detective quantum efficiency (DQE) and output of movie data. A high ratio of camera frame rate (frames per second) to camera exposure rate (electrons per pixel per second) allows electron counting, which further improves the DQE and enables the recording of super-resolution information. Movie output also allows the correction of specimen movement and compensation for radiation damage.
View Article and Find Full Text PDFBackground: Immobilization devices are crucial to minimize patient positioning uncertainties in radiotherapy (RT) treatments. Accurate inter and intra-fraction motions is particularly important for intracranial and stereotactic radiation treatment which require high precision in dose delivery. Recently, a new immobilization device has been developed specifically for the radiation treatment of intracranial malignancies.
View Article and Find Full Text PDFAutomatic or semiautomatic data collection approaches on a transmission electron microscope (TEM) for Single Particle Analysis, capable of acquiring large datasets composed of only high quality images, are of great importance to obtain 3D density maps with the highest resolution possible. Typically, this task is performed by an experienced microscopist, who manually decides to keep or discard images according to subjective criteria. Therefore, this methodology is slow, intensive in human work and subjective.
View Article and Find Full Text PDFCurrent approaches in Dutch mental health care institutions towards inpatients' aggression have focused predominantly on environmental factors, such as training the staff in aggression management. However, personality traits might be an important factor in patients' aggression - as shown by incidents in the wards. This study explores the influence of dysfunctional impulsivity and alexithymia on psychiatric patients' aggressive behavior, through self-reports and through involvement in aggressive incidents.
View Article and Find Full Text PDFPurpose: The satisfaction-of-search (SOS) effect occurs when an abnormality on an image is missed because another is found. The aim of this experiment was to test whether severe distracting fractures control the magnitude of SOS on other fractures when both appear in a single CT image.
Methods: The institutional review board approved this study.
Rationale And Objectives: Although a checklist has been recommended for preventing satisfaction of search (SOS) errors, a previous research study did not demonstrate that benefit. However, observers in that study had to turn away from the image display to use the checklist. The current study tested a vocalized checklist to avoid this constraint.
View Article and Find Full Text PDFRationale And Objectives: Two decades have passed since the publication of laboratory studies of satisfaction of search (SOS) in chest radiography. Those studies were performed using film. The current investigation tests for SOS effects in computed radiography of the chest.
View Article and Find Full Text PDFWe report the outcomes of the discussion initiated at the workshop entitled A 3D Cellular Context for the Macromolecular World and propose how data from emerging three-dimensional (3D) cellular imaging techniques—such as electron tomography, 3D scanning electron microscopy and soft X-ray tomography—should be archived, curated, validated and disseminated, to enable their interpretation and reuse by the biomedical community.
View Article and Find Full Text PDFCryo-electron tomography (CET) is the only available technique capable of characterizing the structure of biological macromolecules in conditions close to the native state. With the advent of subtomogram averaging, as a post-processing step to CET, resolutions in the (sub-) nanometer range have become within reach. In addition to advances in instrumentation and experiments, the reconstruction scheme has improved by inclusion of more accurate contrast transfer function (CTF) correction methods, better defocus estimation, and better alignments of the tilt-series and subtomograms.
View Article and Find Full Text PDFObjectives In three experiments, we studied the detection of multiple abnormality types using the satisfaction of search (SOS) paradigm, the provision of a computer-aided detection (CAD) of pulmonary nodules and a focused nodule detection task. Methods 51 chest CT examinations (24 that demonstrated subtle pulmonary nodules and 27 that demonstrated no pulmonary nodules) were read by 15 radiology residents and fellows under two experimental conditions: (1) when there were no other abnormalities present except test abnormalities in the exams (non-SOS condition), and (2) when other abnormalities were present in the exams (SOS condition). Trials from the two conditions were intermixed.
View Article and Find Full Text PDFRationale And Objectives: We tested whether satisfaction of search (SOS) effects that occur in computed tomography (CT) examination of the chest on detection of native abnormalities are produced by the addition of simulated pulmonary nodules.
Materials And Methods: Two experiments were conducted. In the first experiment, 70 CT examinations, half that demonstrated diverse, subtle abnormalities and half that demonstrated no native lesions, were read by 18 radiology residents and fellows under two experimental conditions: presented with and without pulmonary nodules.
Objectives: In three experiments, we studied the detection of multiple abnormality types using the satisfaction of search (SOS) paradigm, the provision of a computer-aided detection (CAD) of pulmonary nodules and a focused nodule detection task.
Methods: 51 chest CT examinations (24 that demonstrated subtle pulmonary nodules and 27 that demonstrated no pulmonary nodules) were read by 15 radiology residents and fellows under two experimental conditions: (1) when there were no other abnormalities present except test abnormalities in the exams (non-SOS condition), and (2) when other abnormalities were present in the exams (SOS condition). Trials from the two conditions were intermixed.
We have developed new methods for contrast transfer function (CTF) correction of tilted and/or thick specimens. In order to achieve higher resolutions in cryo-electron tomography (CryoET), it is necessary to account for the defocus gradient on a tilted specimen and possibly the defocus gradient within a thick specimen. CTF correction methods which account for these defocus differences have recently gained interest.
View Article and Find Full Text PDFPurpose: The aim of this experiment was to test whether radiographs of major injuries, those having serious consequences for life and limb, produce a satisfaction-of-search (SOS) effect on the detection of subtle, nondisplaced test fractures.
Methods: Institutional review board approval and informed consent from 24 participants were obtained. Seventy simulated patients with multiple trauma injuries were constructed from radiographs of 3 different anatomic areas demonstrated only skeletal injuries.
The aim of the present study was to determine the prevalence of mandibular asymmetries during the mixed dentition in growing children. For this purpose, a retrospective study was designed where various measurements were performed on the right and left sides of the mandible of panoramic radiographs of 327 children (males: 169; females: 158), 8-12 years old. Four linear measurements, mandibular ramus height, ramus width, corpus height, and corpus length, and two angles, mandibular gonial (Go) and mandibular condyle (Co), and the developmental stage of the permanent lower second molar were analysed.
View Article and Find Full Text PDFThis study presents data for verification of the iPlan RT Monte Carlo (MC) dose algorithm (BrainLAB, Feldkirchen, Germany). MC calculations were compared with pencil beam (PB) calculations and verification measurements in phantoms with lung-equivalent material, air cavities or bone-equivalent material to mimic head and neck and thorax and in an Alderson anthropomorphic phantom. Dosimetric accuracy of MC for the micro-multileaf collimator (MLC) simulation was tested in a homogeneous phantom.
View Article and Find Full Text PDFTomosynthesis was developed for mammography, especially breast cancer detection. However, its limited-angular range scan and resultant data incompleteness causes strong image artifacts and distortions. To address this problem, a hybrid imaging method was proposed in our previous work, which combines tomosynthesis and low-resolution CT into a single system to produce fewer artifacts and distortions at a similar dose level.
View Article and Find Full Text PDFMammography is an effective imaging tool for detecting breast cancer at an early stage and is the only screening modality proved to reduce mortality from breast cancer. However, the overlap of tissues depicted on mammograms may create significant obstacles to the detection and diagnosis of abnormalities. Diagnostic testing initiated because of a questionable result at screening mammography frequently causes patients unnecessary anxiety and incurs increased medical costs.
View Article and Find Full Text PDFCurr Probl Diagn Radiol
February 2008
Although the concept of triangulation of breast lesions has been well-defined in the literature, it is still frequently misunderstood or applied incorrectly. We provide a review of the basic concept, discuss common misapplications of triangulation and the reasons they happen, and demonstrate typical and exceptional cases, as well as mammography-ultrasound correlations using diagrams and illustrative cases.
View Article and Find Full Text PDFRationale And Objectives: Computer-aided diagnosis (CAD) has been developed to ensure that the radiologist considers suspect focal opacities that may represent cancer in chest radiography. Although CAD was not developed to counteract the satisfaction of search (SOS) effect, it may be an effective intervention to do so. The objective of this study is to determine whether an idealized CAD can reduce SOS effects in chest radiography.
View Article and Find Full Text PDFRationale And Objectives: Satisfaction of search (SOS) occurs when an abnormality is missed because another abnormality has been detected. This research studied whether the severity of a detected fracture determines whether subsequent fractures are overlooked.
Materials And Methods: Each of 70 simulated multitrauma patients presented examinations of three anatomic areas.