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Sample records for 3d ct scanning

  1. An automatic approach for 3D registration of CT scans

    NASA Astrophysics Data System (ADS)

    Hu, Yang; Saber, Eli; Dianat, Sohail; Vantaram, Sreenath Rao; Abhyankar, Vishwas

    2012-03-01

    CT (Computed tomography) is a widely employed imaging modality in the medical field. Normally, a volume of CT scans is prescribed by a doctor when a specific region of the body (typically neck to groin) is suspected of being abnormal. The doctors are required to make professional diagnoses based upon the obtained datasets. In this paper, we propose an automatic registration algorithm that helps healthcare personnel to automatically align corresponding scans from 'Study' to 'Atlas'. The proposed algorithm is capable of aligning both 'Atlas' and 'Study' into the same resolution through 3D interpolation. After retrieving the scanned slice volume in the 'Study' and the corresponding volume in the original 'Atlas' dataset, a 3D cross correlation method is used to identify and register various body parts.

  2. 3D dosimetry by optical-CT scanning

    PubMed Central

    Oldham, Mark

    2007-01-01

    The need for an accurate, practical, low-cost 3D dosimetry system is becoming ever more critical as modern dose delivery techniques increase in complexity and sophistication. A recent report from the Radiological Physics Center (RPC) (1), revealed that 38% of institutions failed the head-and-neck IMRT phantom credentialing test at the first attempt. This was despite generous passing criteria (within 7% dose-difference or 4mm distance-to-agreement) evaluated at a half-dozen points and a single axial plane. The question that arises from this disturbing finding is – what percentage of institutions would have failed if a comprehensive 3D measurement had been feasible, rather than measurements restricted to the central film-plane and TLD points? This question can only be adequately answered by a comprehensive 3D-dosimetry system, which presents a compelling argument for its development as a clinically viable low cost dosimetry solution. Optical-CT dosimetry is perhaps the closest system to providing such a comprehensive solution. In this article, we review the origins and recent developments of optical-CT dosimetry systems. The principle focus is on first generation systems known to have highest accuracy but longer scan times. PMID:17460781

  3. "High-precision, reconstructed 3D model" of skull scanned by conebeam CT: Reproducibility verified using CAD/CAM data.

    PubMed

    Katsumura, Seiko; Sato, Keita; Ikawa, Tomoko; Yamamura, Keiko; Ando, Eriko; Shigeta, Yuko; Ogawa, Takumi

    2016-01-01

    Computed tomography (CT) scanning has recently been introduced into forensic medicine and dentistry. However, the presence of metal restorations in the dentition can adversely affect the quality of three-dimensional reconstruction from CT scans. In this study, we aimed to evaluate the reproducibility of a "high-precision, reconstructed 3D model" obtained from a conebeam CT scan of dentition, a method that might be particularly helpful in forensic medicine. We took conebeam CT and helical CT images of three dry skulls marked with 47 measuring points; reconstructed three-dimensional images; and measured the distances between the points in the 3D images with a computer-aided design/computer-aided manufacturing (CAD/CAM) marker. We found that in comparison with the helical CT, conebeam CT is capable of reproducing measurements closer to those obtained from the actual samples. In conclusion, our study indicated that the image-reproduction from a conebeam CT scan was more accurate than that from a helical CT scan. Furthermore, the "high-precision reconstructed 3D model" facilitates reliable visualization of full-sized oral and maxillofacial regions in both helical and conebeam CT scans. PMID:26832374

  4. Voxel-based 2-D/3-D registration of fluoroscopy images and CT scans for image-guided surgery.

    PubMed

    Weese, J; Penney, G P; Desmedt, P; Buzug, T M; Hill, D L; Hawkes, D J

    1997-12-01

    Registration of intraoperative fluoroscopy images with preoperative three-dimensional (3-D) CT images can be used for several purposes in image-guided surgery. On the one hand, it can be used to display the position of surgical instruments, which are being tracked by a localizer, in the preoperative CT scan. On the other hand, the registration result can be used to project preoperative planning information or important anatomical structures visible in the CT image onto the fluoroscopy image. For this registration task, a novel voxel-based method in combination with a new similarity measure (pattern intensity) has been developed. The basic concept of the method is explained at the example of two-dimensional (2-D)/3-D registration of a vertebra in an X-ray fluoroscopy image with a 3-D CT image. The registration method is described, and the results for a spine phantom are presented and discussed. Registration has been carried out repeatedly with different starting estimates to study the capture range. Information about registration accuracy has been obtained by comparing the registration results with a highly accurate "ground-truth" registration, which has been derived from fiducial markers attached to the phantom prior to imaging. In addition, registration results for different vertebrae have been compared. The results show that the rotation parameters and the shifts parallel to the projection plane can accurately be determined from a single projection. Because of the projection geometry, the accuracy of the height above the projection plane is significantly lower. PMID:11020832

  5. The Use Of Computerized Tomographic (CT) Scans For 3-D Display And Prosthesis Construction

    NASA Astrophysics Data System (ADS)

    Mankovich, Nicholas J.; Woodruff, Tracey J.; Beumer, John

    1985-06-01

    The construction of preformed cranial prostheses for large cranial bony defects is both error prone and time consuming. We discuss a method used for the creation of cranial prostheses from automatically extracted bone contours taken from Computerized Tomographic (CT) scans. Previous methods of prosthesis construction have relied on the making of a mold directly from the region of cranial defect. The use of image processing, bone contour extraction, and three-dimensional display allowed us to create a better fitting prosthesis while reducing patient surgery time. This procedure involves direct bone margin extraction from the digital CT images followed by head model construction from serial plots of the bone margin. Three-dimensional data display is used to verify the integrity of the skull data set prior to model construction. Once created, the model is used to fabricate a custom fitting prosthesis which is then surgically implanted. This procedure is being used with patients in the Maxillofacial Prosthetic Clinic at UCLA and this paper details the technique.

  6. Non-invasive transcranial ultrasound therapy based on a 3D CT scan: protocol validation and in vitro results

    NASA Astrophysics Data System (ADS)

    Marquet, F.; Pernot, M.; Aubry, J.-F.; Montaldo, G.; Marsac, L.; Tanter, M.; Fink, M.

    2009-05-01

    A non-invasive protocol for transcranial brain tissue ablation with ultrasound is studied and validated in vitro. The skull induces strong aberrations both in phase and in amplitude, resulting in a severe degradation of the beam shape. Adaptive corrections of the distortions induced by the skull bone are performed using a previous 3D computational tomography scan acquisition (CT) of the skull bone structure. These CT scan data are used as entry parameters in a FDTD (finite differences time domain) simulation of the full wave propagation equation. A numerical computation is used to deduce the impulse response relating the targeted location and the ultrasound therapeutic array, thus providing a virtual time-reversal mirror. This impulse response is then time-reversed and transmitted experimentally by a therapeutic array positioned exactly in the same referential frame as the one used during CT scan acquisitions. In vitro experiments are conducted on monkey and human skull specimens using an array of 300 transmit elements working at a central frequency of 1 MHz. These experiments show a precise refocusing of the ultrasonic beam at the targeted location with a positioning error lower than 0.7 mm. The complete validation of this transcranial adaptive focusing procedure paves the way to in vivo animal and human transcranial HIFU investigations.

  7. Computer-aided diagnosis of pulmonary nodules on CT scans: Segmentation and classification using 3D active contours

    PubMed Central

    Way, Ted W.; Hadjiiski, Lubomir M.; Sahiner, Berkman; Chan, Heang-Ping; Cascade, Philip N.; Kazerooni, Ella A.; Bogot, Naama; Zhou, Chuan

    2009-01-01

    We are developing a computer-aided diagnosis (CAD) system to classify malignant and benign lung nodules found on CT scans. A fully automated system was designed to segment the nodule from its surrounding structured background in a local volume of interest (VOI) and to extract image features for classification. Image segmentation was performed with a three-dimensional (3D) active contour (AC) method. A data set of 96 lung nodules (44 malignant, 52 benign) from 58 patients was used in this study. The 3D AC model is based on two-dimensional AC with the addition of three new energy components to take advantage of 3D information: (1) 3D gradient, which guides the active contour to seek the object surface, (2) 3D curvature, which imposes a smoothness constraint in the z direction, and (3) mask energy, which penalizes contours that grow beyond the pleura or thoracic wall. The search for the best energy weights in the 3D AC model was guided by a simplex optimization method. Morphological and gray-level features were extracted from the segmented nodule. The rubber band straightening transform (RBST) was applied to the shell of voxels surrounding the nodule. Texture features based on run-length statistics were extracted from the RBST image. A linear discriminant analysis classifier with stepwise feature selection was designed using a second simplex optimization to select the most effective features. Leave-one-case-out resampling was used to train and test the CAD system. The system achieved a test area under the receiver operating characteristic curve (Az) of 0.83±0.04. Our preliminary results indicate that use of the 3D AC model and the 3D texture features surrounding the nodule is a promising approach to the segmentation and classification of lung nodules with CAD. The segmentation performance of the 3D AC model trained with our data set was evaluated with 23 nodules available in the Lung Image Database Consortium (LIDC). The lung nodule volumes segmented by the 3D AC

  8. CT scans and 3D reconstructions of Florida manatee (Trichechus manatus latirostris) heads and ear bones.

    PubMed

    Chapla, Marie E; Nowacek, Douglas P; Rommel, Sentiel A; Sadler, Valerie M

    2007-06-01

    The auditory anatomy of the Florida manatee (Trichechus manatus latirostris) was investigated using computerized tomography (CT), three-dimensional reconstructions, and traditional dissection of heads removed during necropsy. The densities (kg/m3) of the soft tissues of the head were measured directly using the displacement method and those of the soft tissues and bone were calculated from CT measurements (Hounsfield units). The manatee's fatty tissue was significantly less dense than the other soft tissues within the head (p<0.05). The squamosal bone was significantly less dense than the other bones of the head (p<0.05). Measurements of the ear bones (tympanic, periotic, malleus, incus, and stapes) collected during dissection revealed that the ossicular chain was overly massive for the mass of the tympanoperiotic complex. PMID:17420106

  9. CT Scans

    MedlinePlus

    ... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...

  10. 3D light scanning macrography.

    PubMed

    Huber, D; Keller, M; Robert, D

    2001-08-01

    The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences. PMID:11489078

  11. Marsupialisation for keratocystic odontogenic tumours in the mandible: longitudinal image analysis of tumour size using 3D visualised CT scans.

    PubMed

    Shudou, H; Sasaki, M; Yamashiro, T; Tsunomachi, S; Takenoshita, Y; Kubota, Y; Ninomiya, T; Kawazu, T; Mori, Y

    2012-03-01

    The purpose of this study was to determine how keratocystic odontogenic tumours (KCOTs) in the mandible are reduced during marsupialisation, and to predict the best time for secondary enucleation by analysing computed tomography (CT) images. 15 patients with KCOTs were treated with marsupialisation surgery, and 42 series of CT data taken during the marsupialisation process were analysed. CT data were reconstructed in three-dimensional (3D) images. The 3D images were used to measure the diameter and volume, and to analyse the changes that occurred after marsupialisation. Marsupialised KCOTs tended to be reduced equally towards the window in the tumour. The amount of volume reduction per day (V(r)) was reduced in proportion to the volume (V) with the formula V(r)=-0.0029×V. The formula manipulation for V was V=V(0)×e(-0.0029t) (t=duration after marsupialisaton (day)). The volume of marsupialised KCOTs was reduced by half over a 239 day cycle. These results demonstrate that the future shape of marsupialised mandibular KCOTs, under good control, could be predicted with significant accuracy using CT data. This prediction could decrease the prolonged marsupialisation state in patients with KCOTs. PMID:22113115

  12. Fast, large field-of-view, telecentric optical-CT scanning system for 3D radiochromic dosimetry

    PubMed Central

    Thomas, A; Oldham, M

    2010-01-01

    We describe initial experiences with an in-house, fast, large field-of-view optical-CT telecentric scanner (the Duke Large field of view Optical-CT Scanner (DLOS)). The DLOS system is designed to enable telecentric optical-CT imaging of dosimeters up to 24 cm in diameter with a spatial resolution of 1 mm3, in approximately 10 minutes. These capabilities render the DLOS system a unique device at present. The system is a scaled up version of early prototypes in our lab. This scaling introduces several challenges, including the accurate measurement of a greatly increased range of light attenuation within the dosimeter, and the need to reduce even minor reflections and scattered light within the imaging chain. We present several corrections and techniques that enable accurate, low noise, 3D dosimetery with the DLOS system. PMID:21218169

  13. Chest CT Scan

    MedlinePlus

    ... pictures to create a very detailed, three-dimensional (3D) model of organs. Sometimes, a substance called contrast dye is injected into a vein in your arm for the CT scan. This substance highlights areas in your chest, which ...

  14. Contrast Enhancement of MicroCT Scans to Aid 3D Modelling of Carbon Fibre Fabric Composites

    NASA Astrophysics Data System (ADS)

    Djukic, Luke P.; Pearce, Garth M.; Herszberg, Israel; Bannister, Michael K.; Mollenhauer, David H.

    2013-12-01

    This paper presents a methodology for volume capture and rendering of plain weave and multi-layer fabric meso-architectures within a consolidated, cured laminate. Micro X-ray Computed Tomography (MicroCT) is an excellent tool for the non-destructive visualisation of material microstructures however the contrast between tows and resin is poor for carbon fibre composites. Firstly, this paper demonstrates techniques to improve the contrast of the microCT images by introducing higher density materials such as gold, iodine and glass into the fabric. Two approaches were demonstrated to be effective for enhancing the differentiation between the tows in the reconstructed microCT visualisations. Secondly, a method of generating three-dimensional volume models of woven composites using microCT scan data is discussed. The process of generating a model is explained from initial manufacture with the aid of an example plain weave fabric. These methods are to be used in the finite element modelling of three-dimensional fabric preforms in future work.

  15. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial ... or other growth (mass) Cerebral atrophy (loss of brain tissue) ... with the hearing nerve Stroke or transient ischemic attack (TIA)

  16. FACE-R--a 3D database of 400 living individuals' full head CT- and face scans and preliminary GMM analysis for craniofacial reconstruction.

    PubMed

    Kustár, Agnes; Forró, Laszlo; Kalina, Ildiko; Fazekas, Ferenc; Honti, Szabolcs; Makra, Szabolcs; Friess, Martin

    2013-11-01

    In the past, improvements in craniofacial reconstructions (CFR) methodology languished due to the lack of adequate 3D databases that were sufficiently large and appropriate for 3-dimensional shape statistics. In our study, we created the "FACE-R" database from CT records and 3D surface scans of 400 clinical patients from Hungary, providing a significantly larger sample that was available before. The uniqueness of our database is linking of two data types that makes possible to investigate the bone and skin surface of the same individual, in upright position, thus eliminating many of the gravitational effects on the face during CT scanning. We performed a preliminary geometric morphometric (GMM) study using 3D data that produces a general idea of skull and face shape correlations. The vertical position of the tip of the (soft) nose for a skull and landmarks such as rhinion need to be taken into account. Likewise, the anterior nasal spine appears to exert some influence in this regard. PMID:24020394

  17. Analysis of the Geometry of the Distal Femur and Proximal Tibia in the Osteoarthritic Knee: A 3D Reconstruction CT Scan Based Study of 449 Cases

    PubMed Central

    Lyras, Dimitrios N.; Loucks, Craig; Greenhow, Robert

    2016-01-01

    Background: The aim of this study is to evaluate the geometry of the distal femur and the proximal tibia in the osteoarthritic knee using 3D reconstructive CT scan imaging. Methods: 449 patients with knee osteoarthritis were treated surgically in our center with patient-specific technology total knee arthroplasty. Preoperatively, all the patients underwent a CT scan according to a standard protocol. Using this database, the Hip-Knee-Angle (HKA), the Femur Valgus Angle (FVA), the Tibia Varus Angle (TVA), the Posterior Tibia Slope (PTS), and the angle between the posterior condylar axis and the anatomical transepicondylar axis (PCA) for each patient were recorded and statistically evaluated. Results: In overall, the mean HKA angle was 177.3±5.55, the mean FVA angle was 3.19±2.08, the mean TVA was 3.28±2.35, the PTS angle was 9.02±3.46, and the PCA angle was 2.86±0.78. Evaluation of the correlations between HKA and PCA (r=0.035), HKA and PTS (r=-0.047), and PCA and PTS (r=0.05) showed non-significant relationships (P=0.46, P=0.32, and P=0.29 respectively). No significant differences were revealed from the comparison of male patients with female patients, regarding the mean HKA, FVA, TVA, PTS, and PCA. Conclusion: The posterior condylar axis is a well-defined but not a reliable axis, while the transepicondylar and the anteroposterior are reliable, but not easily defined axes. Given the large ranges and standard deviations of the location of posterior condylar axis, and the important inter- and intraobserver variability in the intraoperative location of the transepicondylar and the anteroposterior axes, the use of a preoperative 3D CT scan is recommended. PMID:27200387

  18. CT scan

    MedlinePlus

    CAT scan; Computed axial tomography scan; Computed tomography scan ... Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, et al. eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ...

  19. CT scan

    MedlinePlus

    ... that slides into the center of the CT scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you. Modern spiral scanners can perform the exam without stopping. A computer ...

  20. New 3D Bolton standards: coregistration of biplane x rays and 3D CT

    NASA Astrophysics Data System (ADS)

    Dean, David; Subramanyan, Krishna; Kim, Eun-Kyung

    1997-04-01

    The Bolton Standards 'normative' cohort (16 males, 16 females) have been invited back to the Bolton-Brush Growth Study Center for new biorthogonal plain film head x-rays and 3D (three dimensional) head CT-scans. A set of 29 3D landmarks were identified on both their biplane head film and 3D CT images. The current 3D CT image is then superimposed onto the landmarks collected from the current biplane head films. Three post-doctoral fellows have collected 37 3D landmarks from the Bolton Standards' 40 - 70 year old biplane head films. These films were captured annually during their growing period (ages 3 - 18). Using 29 of these landmarks the current 3D CT image is next warped (via thin plate spline) to landmarks taken from each participant's 18th year biplane head films, a process that is successively reiterated back to age 3. This process is demonstrated here for one of the Bolton Standards. The outer skull surfaces will be extracted from each warped 3D CT image and an average will be generated for each age/sex group. The resulting longitudinal series of average 'normative' boney skull surface images may be useful for craniofacial patient: diagnosis, treatment planning, stereotactic procedures, and outcomes assessment.

  1. SU-D-201-07: Exploring the Utility of 4D FDG-PET/CT Scans in Design of Radiation Therapy Planning Compared with 3D PET/CT: A Prospective Study

    SciTech Connect

    Ma, C; Yin, Y

    2015-06-15

    Purpose: A method using four-dimensional(4D) PET/CT in design of radiation treatment planning was proposed and the target volume and radiation dose distribution changes relative to standard three-dimensional (3D) PET/CT were examined. Methods: A target deformable registration method was used by which the whole patient’s respiration process was considered and the effect of respiration motion was minimized when designing radiotherapy planning. The gross tumor volume of a non-small-cell lung cancer was contoured on the 4D FDG-PET/CT and 3D PET/CT scans by use of two different techniques: manual contouring by an experienced radiation oncologist using a predetermined protocol; another technique using a constant threshold of standardized uptake value (SUV) greater than 2.5. The target volume and radiotherapy dose distribution between VOL3D and VOL4D were analyzed. Results: For all phases, the average automatic and manually GTV volume was 18.61 cm3 (range, 16.39–22.03 cm3) and 31.29 cm3 (range, 30.11–35.55 cm3), respectively. The automatic and manually volume of merged IGTV were 27.82 cm3 and 49.37 cm3, respectively. For the manual contour, compared to 3D plan the mean dose for the left, right, and total lung of 4D plan have an average decrease 21.55%, 15.17% and 15.86%, respectively. The maximum dose of spinal cord has an average decrease 2.35%. For the automatic contour, the mean dose for the left, right, and total lung have an average decrease 23.48%, 16.84% and 17.44%, respectively. The maximum dose of spinal cord has an average decrease 1.68%. Conclusion: In comparison to 3D PET/CT, 4D PET/CT may better define the extent of moving tumors and reduce the contouring tumor volume thereby optimize radiation treatment planning for lung tumors.

  2. Heart CT scan

    MedlinePlus

    CAT scan - heart; Computed axial tomography scan - heart; Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agaston score; Coronary calcium scan

  3. Development of a 3D CT scanner using cone beam

    NASA Astrophysics Data System (ADS)

    Endo, Masahiro; Kamagata, Nozomu; Sato, Kazumasa; Hattori, Yuichi; Kobayashi, Shigeo; Mizuno, Shinichi; Jimbo, Masao; Kusakabe, Masahiro

    1995-05-01

    In order to acquire 3D data of high contrast objects such as bone, lung and vessels enhanced by contrast media for use in 3D image processing, we have developed a 3D CT-scanner using cone beam x ray. The 3D CT-scanner consists of a gantry and a patient couch. The gantry consists of an x-ray tube designed for cone beam CT and a large area two-dimensional detector mounted on a single frame and rotated around an object in 12 seconds. The large area detector consists of a fluorescent plate and a charge coupled device video camera. The size of detection area was 600 mm X 450 mm capable of covering the total chest. While an x-ray tube was rotated around an object, pulsed x ray was exposed 30 times a second and 360 projected images were collected in a 12 second scan. A 256 X 256 X 256 matrix image (1.25 mm X 1.25 mm X 1.25 mm voxel) was reconstructed by a high-speed reconstruction engine. Reconstruction time was approximately 6 minutes. Cylindrical water phantoms, anesthetized rabbits with or without contrast media, and a Japanese macaque were scanned with the 3D CT-scanner. The results seem promising because they show high spatial resolution in three directions, though there existed several point to be improved. Possible improvements are discussed.

  4. Arm CT scan

    MedlinePlus

    CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Mosby; 2013:chap 57. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  5. Sinus CT scan

    MedlinePlus

    CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... 2014:chap 67. Shaw AS, Dixon AK. Multidetector computed tomography. In: Adam A, Dixon AK, eds. Grainger & Allison's ...

  6. Leg CT scan

    MedlinePlus

    CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... Saunders; 2012:chap 11. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  7. Pelvic CT scan

    MedlinePlus

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... gov/pubmed/18381118 . Shaw AS, Dixon AK. Multidetector computed tomography. In: Grainger RC, Allison D, Adam, Dixon AK, ...

  8. Shoulder CT scan

    MedlinePlus

    CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Mosby; 2012:chap 57. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  9. Orbit CT scan

    MedlinePlus

    ... results may mean: Bleeding Broken eye socket bone Graves disease Infection Tumor Risks CT scans and other x- ... Livingstone; 2014:chap 66. Read More CT scan Graves disease Tumor Update Date 1/18/2015 Updated by: ...

  10. Lumbar spine CT scan

    MedlinePlus

    CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... stopping.) A computer creates separate images of the spine area, called slices. These images can be stored, ...

  11. CT scan (image)

    MedlinePlus

    CT stands for computerized tomography. In this procedure, a thin X-ray beam is rotated around the ... D image of a section through the body. CT scans are very detailed and provide excellent information ...

  12. SU-E-J-164: An Investigation of a Low-Cost ‘dry’ Optical-CT Scanning System for 3D Dosimetry

    SciTech Connect

    Bache, S; Malcolm, J; Adamovics, J; Oldham, M

    2014-06-01

    Purpose: To characterize and explore the efficacy of a novel low-cost, lowfluid, broad-beam optical-CT system for 3D-dosimetry in radiochromic Presage dosimeters. Leading current optical-CT systems incorporate expensive glass-based telecentric lens technology, and a fluid bath with substantial amounts of fluid (which introduces an inconvenience factor) to minimize refraction artifacts. Here we introduce a novel system which addresses both these limitations by: (1) the use of Fresnel lenses in a telecentric arrangement, and (2) a ‘solid’ fluid bath which dramatically reduces the amount of fluid required for refractive-index (RI) matching. Materials Methods: A fresnel based telecentric optical-CT system was constructed which expands light from a single red LED source into a nominally parallel beam into which a cubic ‘dry-tank’ is placed. The drytank consists of a solid polyurethane cube (with the same RI as Presage) but containing a cylindrical cavity (11.5cm diameter × 11cm ) into which the dosimeter is placed for imaging. A narrow (1-3mm) gap between the walls of the dosimeter and dry-tank is filled with a fluid of similar RI. This arrangement reduces the amount of RI fluid from about 1000cc to 75cc, yielding substantial practical benefit in convenience and cost. The new system was evaluated in direct comparison against Eclipse planning system from a 4-field parallel-opposed treatmen Results: Gamma calculations of dose from DFOS-dry system versus Eclipse showed 92% and 97% agreement with 4mm/4% and 5mm/5% criteria, respectively, in the central 80% of dose distribution. Reconstructions showed some edge artifacts, as well as some dose underestimation towards the dosimeter edge. Conclusion: The implementation of Fresnel based ‘dry’ optical-CT for 3Ddosimetry would represent an important advance enhancing costeffectiveness and practical viability. The performance of the prototype presented here is not yet comparable to the state-of-the-art, but shows

  13. Pediatric CT Scans

    Cancer.gov

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  14. Integrating visible light 3D scanning into the everyday world

    NASA Astrophysics Data System (ADS)

    Straub, Jeremy

    2015-05-01

    Visible light 3D scanning offers the potential to non-invasively and nearly non-perceptibly incorporate 3D imaging into the everyday world. This paper considers the various possible uses of visible light 3D scanning technology. It discusses multiple possible usage scenarios including in hospitals, security perimeter settings and retail environments. The paper presents a framework for assessing the efficacy of visible light 3D scanning for a given application (and compares this to other scanning approaches such as those using blue light or lasers). It also discusses ethical and legal considerations relevant to real-world use and concludes by presenting a decision making framework.

  15. 3D scanning modeling method application in ancient city reconstruction

    NASA Astrophysics Data System (ADS)

    Ren, Pu; Zhou, Mingquan; Du, Guoguang; Shui, Wuyang; Zhou, Pengbo

    2015-07-01

    With the development of optical engineering technology, the precision of 3D scanning equipment becomes higher, and its role in 3D modeling is getting more distinctive. This paper proposed a 3D scanning modeling method that has been successfully applied in Chinese ancient city reconstruction. On one hand, for the existing architectures, an improved algorithm based on multiple scanning is adopted. Firstly, two pieces of scanning data were rough rigid registered using spherical displacers and vertex clustering method. Secondly, a global weighted ICP (iterative closest points) method is used to achieve a fine rigid registration. On the other hand, for the buildings which have already disappeared, an exemplar-driven algorithm for rapid modeling was proposed. Based on the 3D scanning technology and the historical data, a system approach was proposed for 3D modeling and virtual display of ancient city.

  16. Nano-CT Scanning

    NASA Astrophysics Data System (ADS)

    Masschaele, B.

    Tomography is a non-destructive research technique which allows investigating the internal structure of objects in 3D . The "centre for X-ray tomography (UGCT)" of the Ghent University has developed a modular X-ray micro/nanoCT scanner which is used for multi-disciplinary research. In this paper we give an overview of the different components of the UGCT scanner with special attention to the X-ray imaging detectors. Also the software tools for data reconstruction and analysis and some obtained results are discussed.

  17. Implementation of 3D Optical Scanning Technology for Automotive Applications.

    PubMed

    Kuş, Abdil

    2009-01-01

    Reverse engineering (RE) is a powerful tool for generating a CAD model from the 3D scan data of a physical part that lacks documentation or has changed from the original CAD design of the part. The process of digitizing a part and creating a CAD model from 3D scan data is less time consuming and provides greater accuracy than manually measuring the part and designing the part from scratch in CAD. 3D optical scanning technology is one of the measurement methods which have evolved over the last few years and it is used in a wide range of areas from industrial applications to art and cultural heritage. It is also used extensively in the automotive industry for applications such as part inspections, scanning of tools without CAD definition, scanning the casting for definition of the stock (i.e. the amount of material to be removed from the surface of the castings) model for CAM programs and reverse engineering. In this study two scanning experiments of automotive applications are illustrated. The first one examines the processes from scanning to re-manufacturing the damaged sheet metal cutting die, using a 3D scanning technique and the second study compares the scanned point clouds data to 3D CAD data for inspection purposes. Furthermore, the deviations of the part holes are determined by using different lenses and scanning parameters. PMID:22573995

  18. Implementation of 3D Optical Scanning Technology for Automotive Applications

    PubMed Central

    Kuş, Abdil

    2009-01-01

    Reverse engineering (RE) is a powerful tool for generating a CAD model from the 3D scan data of a physical part that lacks documentation or has changed from the original CAD design of the part. The process of digitizing a part and creating a CAD model from 3D scan data is less time consuming and provides greater accuracy than manually measuring the part and designing the part from scratch in CAD. 3D optical scanning technology is one of the measurement methods which have evolved over the last few years and it is used in a wide range of areas from industrial applications to art and cultural heritage. It is also used extensively in the automotive industry for applications such as part inspections, scanning of tools without CAD definition, scanning the casting for definition of the stock (i.e. the amount of material to be removed from the surface of the castings) model for CAM programs and reverse engineering. In this study two scanning experiments of automotive applications are illustrated. The first one examines the processes from scanning to re-manufacturing the damaged sheet metal cutting die, using a 3D scanning technique and the second study compares the scanned point clouds data to 3D CAD data for inspection purposes. Furthermore, the deviations of the part holes are determined by using different lenses and scanning parameters. PMID:22573995

  19. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2010-12-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  20. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2011-05-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  1. The dimension added by 3D scanning and 3D printing of meteorites

    NASA Astrophysics Data System (ADS)

    de Vet, S. J.

    2016-01-01

    An overview for the 3D photodocumentation of meteorites is presented, focussing on two 3D scanning methods in relation to 3D printing. The 3D photodocumention of meteorites provides new ways for the digital preservation of culturally, historically or scientifically unique meteorites. It has the potential for becoming a new documentation standard of meteorites that can exist complementary to traditional photographic documentation. Notable applications include (i.) use of physical properties in dark flight-, strewn field-, or aerodynamic modelling; (ii.) collection research of meteorites curated by different museum collections, and (iii.) public dissemination of meteorite models as a resource for educational users. The possible applications provided by the additional dimension of 3D illustrate the benefits for the meteoritics community.

  2. 3D intrathoracic region definition and its application to PET-CT analysis

    NASA Astrophysics Data System (ADS)

    Cheirsilp, Ronnarit; Bascom, Rebecca; Allen, Thomas W.; Higgins, William E.

    2014-03-01

    Recently developed integrated PET-CT scanners give co-registered multimodal data sets that offer complementary three-dimensional (3D) digital images of the chest. PET (positron emission tomography) imaging gives highly specific functional information of suspect cancer sites, while CT (X-ray computed tomography) gives associated anatomical detail. Because the 3D CT and PET scans generally span the body from the eyes to the knees, accurate definition of the intrathoracic region is vital for focusing attention to the central-chest region. In this way, diagnostically important regions of interest (ROIs), such as central-chest lymph nodes and cancer nodules, can be more efficiently isolated. We propose a method for automatic segmentation of the intrathoracic region from a given co-registered 3D PET-CT study. Using the 3D CT scan as input, the method begins by finding an initial intrathoracic region boundary for a given 2D CT section. Next, active contour analysis, driven by a cost function depending on local image gradient, gradient-direction, and contour shape features, iteratively estimates the contours spanning the intrathoracic region on neighboring 2D CT sections. This process continues until the complete region is defined. We next present an interactive system that employs the segmentation method for focused 3D PET-CT chest image analysis. A validation study over a series of PET-CT studies reveals that the segmentation method gives a Dice index accuracy of less than 98%. In addition, further results demonstrate the utility of the method for focused 3D PET-CT chest image analysis, ROI definition, and visualization.

  3. Comparison of physical quality assurance between Scanora 3D and 3D Accuitomo 80 dental CT scanners

    PubMed Central

    Ali, Ahmed S.; Fteita, Dareen; Kulmala, Jarmo

    2015-01-01

    Background The use of cone beam computed tomography (CBCT) in dentistry has proven to be useful in the diagnosis and treatment planning of several oral and maxillofacial diseases. The quality of the resulting image is dictated by many factors related to the patient, unit, and operator. Materials and methods In this work, two dental CBCT units, namely Scanora 3D and 3D Accuitomo 80, were assessed and compared in terms of quantitative effective dose delivered to specific locations in a dosimetry phantom. Resolution and contrast were evaluated in only 3D Accuitomo 80 using special quality assurance phantoms. Results Scanora 3D, with less radiation time, showed less dosing values compared to 3D Accuitomo 80 (mean 0.33 mSv, SD±0.16 vs. 0.18 mSv, SD±0.1). Using paired t-test, no significant difference was found in Accuitomo two scan sessions (p>0.05), while it was highly significant in Scanora (p>0.05). The modulation transfer function value (at 2 lp/mm), in both measurements, was found to be 4.4%. The contrast assessment of 3D Accuitomo 80 in the two measurements showed few differences, for example, the grayscale values were the same (SD=0) while the noise level was slightly different (SD=0 and 0.67, respectively). Conclusions The radiation dose values in these two CBCT units are significantly less than those encountered in systemic CT scans. However, the dose seems to be affected more by changing the field of view rather than the voltage or amperage. The low doses were at the expense of the image quality produced, which was still acceptable. Although the spatial resolution and contrast were inferior to the medical images produced in systemic CT units, the present results recommend adopting CBCTs in maxillofacial imaging because of low radiation dose and adequate image quality. PMID:26091832

  4. Steering knuckle diameter measurement based on optical 3D scanning

    NASA Astrophysics Data System (ADS)

    Song, Li-mei; Li, Da-peng; Chang, Yu-lan; Xi, Jiang-tao; Guo, Qing-hua

    2014-11-01

    To achieve accurate measurements, the creating a fitting hole for internal diameter (CFHID) measurement method and the establishing multi-sectional curve for external diameter (EMCED) measurement method are proposed in this paper, which are based on computer vision principle and three-dimensional (3D) reconstruction. The methods are able to highlight the 3D characteristics of the scanned object and to achieve the accurate measurement of 3D data. It can create favorable conditions for realizing the reverse design and 3D reconstruction of scanned object. These methods can also be applied to dangerous work environment or the occasion that traditional contact measurement can not meet the demands, and they can improve the security in measurement.

  5. On averaging multiview relations for 3D scan registration.

    PubMed

    Govindu, Venu Madhav; Pooja, A

    2014-03-01

    In this paper, we present an extension of the iterative closest point (ICP) algorithm that simultaneously registers multiple 3D scans. While ICP fails to utilize the multiview constraints available, our method exploits the information redundancy in a set of 3D scans by using the averaging of relative motions. This averaging method utilizes the Lie group structure of motions, resulting in a 3D registration method that is both efficient and accurate. In addition, we present two variants of our approach, i.e., a method that solves for multiview 3D registration while obeying causality and a transitive correspondence variant that efficiently solves the correspondence problem across multiple scans. We present experimental results to characterize our method and explain its behavior as well as those of some other multiview registration methods in the literature. We establish the superior accuracy of our method in comparison to these multiview methods with registration results on a set of well-known real datasets of 3D scans. PMID:23412615

  6. Automated 3D vascular segmentation in CT hepatic venography

    NASA Astrophysics Data System (ADS)

    Fetita, Catalin; Lucidarme, Olivier; Preteux, Francoise

    2005-08-01

    In the framework of preoperative evaluation of the hepatic venous anatomy in living-donor liver transplantation or oncologic rejections, this paper proposes an automated approach for the 3D segmentation of the liver vascular structure from 3D CT hepatic venography data. The developed segmentation approach takes into account the specificities of anatomical structures in terms of spatial location, connectivity and morphometric properties. It implements basic and advanced morphological operators (closing, geodesic dilation, gray-level reconstruction, sup-constrained connection cost) in mono- and multi-resolution filtering schemes in order to achieve an automated 3D reconstruction of the opacified hepatic vessels. A thorough investigation of the venous anatomy including morphometric parameter estimation is then possible via computer-vision 3D rendering, interaction and navigation capabilities.

  7. Optical-CT scanning of polymer gels

    PubMed Central

    Oldham, M

    2006-01-01

    The application of optical-CT scanning to achieve accurate high-resolution 3D dosimetry is a subject of current interest. The purpose of this paper is to provide a brief overview of past research and achievements in optical-CT polymer gel dosimetry, and to review current issues and challenges. The origins of optical-CT imaging of light-scattering polymer gels are reviewed. Techniques to characterize and optimize optical-CT performance are presented. Particular attention is given to studies of artifacts in optical-CT imaging, an important area that has not been well studied to date. The technique of optical-CT simulation by Monte-Carlo modeling is introduced as a tool to explore such artifacts. New simulation studies are presented and compared with experimental data. PMID:17082823

  8. 3D scanning and printing skeletal tissues for anatomy education.

    PubMed

    Thomas, Daniel B; Hiscox, Jessica D; Dixon, Blair J; Potgieter, Johan

    2016-09-01

    Detailed anatomical models can be produced with consumer-level 3D scanning and printing systems. 3D replication techniques are significant advances for anatomical education as they allow practitioners to more easily introduce diverse or numerous specimens into classrooms. Here we present a methodology for producing anatomical models in-house, with the chondrocranium cartilage from a spiny dogfish (Squalus acanthias) and the skeleton of a cane toad (Rhinella marina) as case studies. 3D digital replicas were produced using two consumer-level scanners and specimens were 3D-printed with selective laser sintering. The fidelity of the two case study models was determined with respect to key anatomical features. Larger-scale features of the dogfish chondrocranium and frog skeleton were all well-resolved and distinct in the 3D digital models, and many finer-scale features were also well-resolved, but some more subtle features were absent from the digital models (e.g. endolymphatic foramina in chondrocranium). All characters identified in the digital chondrocranium could be identified in the subsequent 3D print; however, three characters in the 3D-printed frog skeleton could not be clearly delimited (palatines, parasphenoid and pubis). Characters that were absent in the digital models or 3D prints had low-relief in the original scanned specimen and represent a minor loss of fidelity. Our method description and case studies show that minimal equipment and training is needed to produce durable skeletal specimens. These technologies support the tailored production of models for specific classes or research aims. PMID:27146106

  9. Pavement cracking measurements using 3D laser-scan images

    NASA Astrophysics Data System (ADS)

    Ouyang, W.; Xu, B.

    2013-10-01

    Pavement condition surveying is vital for pavement maintenance programs that ensure ride quality and traffic safety. This paper first introduces an automated pavement inspection system which uses a three-dimensional (3D) camera and a structured laser light to acquire dense transverse profiles of a pavement lane surface when it carries a moving vehicle. After the calibration, the 3D system can yield a depth resolution of 0.5 mm and a transverse resolution of 1.56 mm pixel-1 at 1.4 m camera height from the ground. The scanning rate of the camera can be set to its maximum at 5000 lines s-1, allowing the density of scanned profiles to vary with the vehicle's speed. The paper then illustrates the algorithms that utilize 3D information to detect pavement distress, such as transverse, longitudinal and alligator cracking, and presents the field tests on the system's repeatability when scanning a sample pavement in multiple runs at the same vehicle speed, at different vehicle speeds and under different weather conditions. The results show that this dedicated 3D system can capture accurate pavement images that detail surface distress, and obtain consistent crack measurements in repeated tests and under different driving and lighting conditions.

  10. 3D reconstruction based on CT image and its application

    NASA Astrophysics Data System (ADS)

    Zhang, Jianxun; Zhang, Mingmin

    2004-03-01

    Reconstitute the 3-D model of the liver and its internal piping system and simulation of the liver surgical operation can increase the accurate and security of the liver surgical operation, attain a purpose for the biggest limit decrease surgical operation wound, shortening surgical operation time, increasing surgical operation succeeding rate, reducing medical treatment expenses and promoting patient recovering from illness. This text expatiated technology and method that the author constitutes 3-D the model of the liver and its internal piping system and simulation of the liver surgical operation according to the images of CT. The direct volume rendering method establishes 3D the model of the liver. Under the environment of OPENGL adopt method of space point rendering to display liver's internal piping system and simulation of the liver surgical operation. Finally, we adopt the wavelet transform method compressed the medical image data.

  11. Factors Affecting Dimensional Accuracy of 3-D Printed Anatomical Structures Derived from CT Data.

    PubMed

    Ogden, Kent M; Aslan, Can; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Soman, Pranav

    2015-12-01

    Additive manufacturing and bio-printing, with the potential for direct fabrication of complex patient-specific anatomies derived from medical scan data, are having an ever-increasing impact on the practice of medicine. Anatomic structures are typically derived from CT or MRI scans, and there are multiple steps in the model derivation process that influence the geometric accuracy of the printed constructs. In this work, we compare the dimensional accuracy of 3-D printed constructs of an L1 vertebra derived from CT data for an ex vivo cadaver T-L spine with the original vertebra. Processing of segmented structures using binary median filters and various surface extraction algorithms is evaluated for the effect on model dimensions. We investigate the effects of changing CT reconstruction kernels by scanning simple geometric objects and measuring the impact on the derived model dimensions. We also investigate if there are significant differences between physical and virtual model measurements. The 3-D models were printed using a commercial 3-D printer, the Replicator 2 (MakerBot, Brooklyn, NY) using polylactic acid (PLA) filament. We found that changing parameters during the scan reconstruction, segmentation, filtering, and surface extraction steps will have an effect on the dimensions of the final model. These effects need to be quantified for specific situations that rely on the accuracy of 3-D printed models used in medicine or tissue engineering applications. PMID:25982877

  12. Knee CT scan

    MedlinePlus

    CAT scan - knee; Computed axial tomography scan - knee; Computed tomography scan - knee ... Saunders; 2015:chap 93. Shaw AS, Prokop M. Computed tomography. In: Adam A, Dixon AK, Gillard JH, Schaefer- ...

  13. 3D Printing of CT Dataset: Validation of an Open Source and Consumer-Available Workflow.

    PubMed

    Bortolotto, Chandra; Eshja, Esmeralda; Peroni, Caterina; Orlandi, Matteo A; Bizzotto, Nicola; Poggi, Paolo

    2016-02-01

    The broad availability of cheap three-dimensional (3D) printing equipment has raised the need for a thorough analysis on its effects on clinical accuracy. Our aim is to determine whether the accuracy of 3D printing process is affected by the use of a low-budget workflow based on open source software and consumer's commercially available 3D printers. A group of test objects was scanned with a 64-slice computed tomography (CT) in order to build their 3D copies. CT datasets were elaborated using a software chain based on three free and open source software. Objects were printed out with a commercially available 3D printer. Both the 3D copies and the test objects were measured using a digital professional caliper. Overall, the objects' mean absolute difference between test objects and 3D copies is 0.23 mm and the mean relative difference amounts to 0.55 %. Our results demonstrate that the accuracy of 3D printing process remains high despite the use of a low-budget workflow. PMID:26175139

  14. Improving low-dose cardiac CT images using 3D sparse representation based processing

    NASA Astrophysics Data System (ADS)

    Shi, Luyao; Chen, Yang; Luo, Limin

    2015-03-01

    Cardiac computed tomography (CCT) has been widely used in diagnoses of coronary artery diseases due to the continuously improving temporal and spatial resolution. When helical CT with a lower pitch scanning mode is used, the effective radiation dose can be significant when compared to other radiological exams. Many methods have been developed to reduce radiation dose in coronary CT exams including high pitch scans using dual source CT scanners and step-and-shot scanning mode for both single source and dual source CT scanners. Additionally, software methods have also been proposed to reduce noise in the reconstructed CT images and thus offering the opportunity to reduce radiation dose while maintaining the desired diagnostic performance of a certain imaging task. In this paper, we propose that low-dose scans should be considered in order to avoid the harm from accumulating unnecessary X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. Accordingly, in this paper, a 3D dictionary representation based image processing method is proposed to reduce CT image noise. Information on both spatial and temporal structure continuity is utilized in sparse representation to improve the performance of the image processing method. Clinical cases were used to validate the proposed method.

  15. Thoracic spine CT scan

    MedlinePlus

    ... that slides into the center of the CT scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you. (Modern "spiral" scanners can perform the exam without stopping.) A computer ...

  16. Head CT scan

    MedlinePlus

    ... that slides into the center of the CT scanner. While inside the scanner, the machine's x-ray beam rotates around you. ... breathing during the test, you should notify the scanner operator immediately. Scanners come with an intercom and ...

  17. Characterization of a parallel-beam CCD optical-CT apparatus for 3D radiation dosimetry.

    PubMed

    Krstajić, Nikola; Doran, Simon J

    2007-07-01

    3D measurement of optical attenuation is of interest in a variety of fields of biomedical importance, including spectrophotometry, optical projection tomography (OPT) and analysis of 3D radiation dosimeters. Accurate, precise and economical 3D measurements of optical density (OD) are a crucial step in enabling 3D radiation dosimeters to enter wider use in clinics. Polymer gels and Fricke gels, as well as dosimeters not based around gels, have been characterized for 3D dosimetry over the last two decades. A separate problem is the verification of the best readout method. A number of different imaging modalities (magnetic resonance imaging (MRI), optical CT, x-ray CT and ultrasound) have been suggested for the readout of information from 3D dosimeters. To date only MRI and laser-based optical CT have been characterized in detail. This paper describes some initial steps we have taken in establishing charge coupled device (CCD)-based optical CT as a viable alternative to MRI for readout of 3D radiation dosimeters. The main advantage of CCD-based optical CT over traditional laser-based optical CT is a speed increase of at least an order of magnitude, while the simplicity of its architecture would lend itself to cheaper implementation than both MRI and laser-based optical CT if the camera itself were inexpensive enough. Specifically, we study the following aspects of optical metrology, using high quality test targets: (i) calibration and quality of absorbance measurements and the camera requirements for 3D dosimetry; (ii) the modulation transfer function (MTF) of individual projections; (iii) signal-to-noise ratio (SNR) in the projection and reconstruction domains; (iv) distortion in the projection domain, depth-of-field (DOF) and telecentricity. The principal results for our current apparatus are as follows: (i) SNR of optical absorbance in projections is better than 120:1 for uniform phantoms in absorbance range 0.3 to 1.6 (and better than 200:1 for absorbances 1.0 to

  18. Characterization of a parallel-beam CCD optical-CT apparatus for 3D radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Krstajic, Nikola; Doran, Simon J.

    2007-07-01

    3D measurement of optical attenuation is of interest in a variety of fields of biomedical importance, including spectrophotometry, optical projection tomography (OPT) and analysis of 3D radiation dosimeters. Accurate, precise and economical 3D measurements of optical density (OD) are a crucial step in enabling 3D radiation dosimeters to enter wider use in clinics. Polymer gels and Fricke gels, as well as dosimeters not based around gels, have been characterized for 3D dosimetry over the last two decades. A separate problem is the verification of the best readout method. A number of different imaging modalities (magnetic resonance imaging (MRI), optical CT, x-ray CT and ultrasound) have been suggested for the readout of information from 3D dosimeters. To date only MRI and laser-based optical CT have been characterized in detail. This paper describes some initial steps we have taken in establishing charge coupled device (CCD)-based optical CT as a viable alternative to MRI for readout of 3D radiation dosimeters. The main advantage of CCD-based optical CT over traditional laser-based optical CT is a speed increase of at least an order of magnitude, while the simplicity of its architecture would lend itself to cheaper implementation than both MRI and laser-based optical CT if the camera itself were inexpensive enough. Specifically, we study the following aspects of optical metrology, using high quality test targets: (i) calibration and quality of absorbance measurements and the camera requirements for 3D dosimetry; (ii) the modulation transfer function (MTF) of individual projections; (iii) signal-to-noise ratio (SNR) in the projection and reconstruction domains; (iv) distortion in the projection domain, depth-of-field (DOF) and telecentricity. The principal results for our current apparatus are as follows: (i) SNR of optical absorbance in projections is better than 120:1 for uniform phantoms in absorbance range 0.3 to 1.6 (and better than 200:1 for absorbances 1.0 to

  19. Automation of 3D scan data capturing and processing

    NASA Astrophysics Data System (ADS)

    Sitnik, Robert; Karaszewski, Maciej; Załuski, Wojciech; Rutkiewicz, Jan

    2010-02-01

    In this paper a fully automated 3D shape measurement and processing method is presented. It assumes that positioning of measurement head in relation to measured object can be realized by specialized computer-controlled manipulator. On the base of existing 3D scans, the proposed method calculates "next best view" position for measurement head. All 3D data processing (filtering, ICP based fitting and final views integration) is performed automatically. Final 3D model is created on the base of user specified parameters like accuracy of surface representation or density of surface sampling. Exemplary system that implements all mentioned functionalities will be presented. The goal of this system is to automatically (without any user attention) and rapidly (from days and weeks to hours) measure whole object with some limitations to its properties: maximum measurement volume is described as a cylinder with 2,5m height and 1m radius, maximum object's weight is 2 tons. Measurement head is automatically calibrated by the system and its possible working volume starts from 120mm x 80mm x 60mm and ends up to 1,2m x 0,8m x 0,6m. Exemplary measurement result is presented.

  20. From 3D Scanning to Analytical Heritage Documentation

    NASA Astrophysics Data System (ADS)

    Schaich, M.

    During the last few years, the number of historical and archaeological items recorded using innovative, three dimensional surveying technologies has increased considerably. Comprehensive digital, photo-realistic 3D recording and modelling yields a huge range of new possibilities for documenting, analysing and safeguarding items of cultural importance. ArcTron GmbH has specialised in electronic surveying and the development of CAD and database information systems for heritage and archaeology for over 12 years employing total stations, laser pantographs and photogrammetry, as well as a variety of laser scanning systems, to generate 3D recordings. Innovative complementary combinations of these technologies allow their respective strengths to be fully exploited. The data resulting from recording techniques of these kinds can be used as a basis for producing documentation of outstanding quality. 3D digital models with photo-realistic texturing, orthophotos, coloured point clouds, 3D damage mapping, rapid prototyping models and multi-media presentations are just some of the potential resulting forms of documentation. Historical monuments and items ranging from huge sections of terrain down to the smallest artefact can be reproduced with such accuracy and to such a high level of realism that documentation of this kind is not only extremely useful for archaeologists, conservators and architectural historians etc. but practically indispensable.

  1. A universal approach for automatic organ segmentations on 3D CT images based on organ localization and 3D GrabCut

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Ito, Takaaki; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2014-03-01

    This paper describes a universal approach to automatic segmentation of different internal organ and tissue regions in three-dimensional (3D) computerized tomography (CT) scans. The proposed approach combines object localization, a probabilistic atlas, and 3D GrabCut techniques to achieve automatic and quick segmentation. The proposed method first detects a tight 3D bounding box that contains the target organ region in CT images and then estimates the prior of each pixel inside the bounding box belonging to the organ region or background based on a dynamically generated probabilistic atlas. Finally, the target organ region is separated from the background by using an improved 3D GrabCut algorithm. A machine-learning method is used to train a detector to localize the 3D bounding box of the target organ using template matching on a selected feature space. A content-based image retrieval method is used for online generation of a patient-specific probabilistic atlas for the target organ based on a database. A 3D GrabCut algorithm is used for final organ segmentation by iteratively estimating the CT number distributions of the target organ and backgrounds using a graph-cuts algorithm. We applied this approach to localize and segment twelve major organ and tissue regions independently based on a database that includes 1300 torso CT scans. In our experiments, we randomly selected numerous CT scans and manually input nine principal types of inner organ regions for performance evaluation. Preliminary results showed the feasibility and efficiency of the proposed approach for addressing automatic organ segmentation issues on CT images.

  2. Appearance of bony lesions on 3-D CT reconstructions: a case study in variable renderings

    NASA Astrophysics Data System (ADS)

    Mankovich, Nicholas J.; White, Stuart C.

    1992-05-01

    This paper discusses conventional 3-D reconstruction for bone visualization and presents a case study to demonstrate the dangers of performing 3-D reconstructions without careful selection of the bone threshold. The visualization of midface bone lesions directly from axial CT images is difficult because of the complex anatomic relationships. Three-dimensional reconstructions made from the CT to provide graphic images showing lesions in relation to adjacent facial bones. Most commercially available 3-D image reconstruction requires that the radiologist or technologist identify a threshold image intensity value that can be used to distinguish bone from other tissues. Much has been made of the many disadvantages of this technique, but it continues as the predominant method in producing 3-D pictures for clinical use. This paper is intended to provide a clear demonstration for the physician of the caveats that should accompany 3-D reconstructions. We present a case of recurrent odontogenic keratocyst in the anterior maxilla where the 3-D reconstructions, made with different bone thresholds (windows), are compared to the resected specimen. A DMI 3200 computer was used to convert the scan data from a GE 9800 CT into a 3-D shaded surface image. Threshold values were assigned to (1) generate the most clinically pleasing image, (2) produce maximum theoretical fidelity (using the midpoint image intensity between average cortical bone and average soft tissue), and (3) cover stepped threshold intensities between these two methods. We compared the computer lesions with the resected specimen and noted measurement errors of up to 44 percent introduced by inappropriate bone threshold levels. We suggest clinically applicable standardization techniques in the 3-D reconstruction as well as cautionary language that should accompany the 3-D images.

  3. Upright 3D Treatment Planning Using a Vertical CT

    SciTech Connect

    Shah, Anand P. Strauss, Jonathan B.; Kirk, Michael C.; Chen, Sea S.; Kroc, Thomas K.; Zusag, Thomas W.

    2009-04-01

    In this report, we describe a novel technique used to plan and administer external beam radiation therapy to a patient in the upright position. A patient required reirradiation for thymic carcinoma but was unable to tolerate the supine position due to bilateral phrenic nerve injury and paralysis of the diaphragm. Computed tomography (CT) images in the upright position were acquired at the Northern Illinois University Institute for Neutron Therapy at Fermilab. The CT data were imported into a standard 3-dimensional (3D) treatment planning system. Treatment was designed to deliver 24 Gy to the target volume while respecting normal tissue tolerances. A custom chair that locked into the treatment table indexing system was constructed for immobilization, and port films verified the reproducibility of setup. Radiation was administered using mixed photon and electron AP fields.

  4. 3D range scan enhancement using image-based methods

    NASA Astrophysics Data System (ADS)

    Herbort, Steffen; Gerken, Britta; Schugk, Daniel; Wöhler, Christian

    2013-10-01

    This paper addresses the problem of 3D surface scan refinement, which is desirable due to noise, outliers, and missing measurements being present in the 3D surfaces obtained with a laser scanner. We present a novel algorithm for the fusion of absolute laser scanner depth profiles and photometrically estimated surface normal data, which yields a noise-reduced and highly detailed depth profile with large scale shape robustness. In contrast to other approaches published in the literature, the presented algorithm (1) regards non-Lambertian surfaces, (2) simultaneously computes surface reflectance (i.e. BRDF) parameters required for 3D reconstruction, (3) models pixelwise incident light and viewing directions, and (4) accounts for interreflections. The algorithm as such relies on the minimization of a three-component error term, which penalizes intensity deviations, integrability deviations, and deviations from the known large-scale surface shape. The solution of the error minimization is obtained iteratively based on a calculus of variations. BRDF parameters are estimated by initially reducing and then iteratively refining the optical resolution, which provides the required robust data basis. The 3D reconstruction of concave surface regions affected by interreflections is improved by compensating global illumination in the image data. The algorithm is evaluated based on eight objects with varying albedos and reflectance behaviors (diffuse, specular, metallic). The qualitative evaluation shows a removal of outliers and a strong reduction of noise, while the large scale shape is preserved. Fine surface details Which are previously not contained in the surface scans, are incorporated through using image data. The algorithm is evaluated with respect to its absolute accuracy using two caliper objects of known shape, and based on synthetically generated data. The beneficial effect of interreflection compensation on the reconstruction accuracy is evaluated quantitatively in a

  5. Single 3D cell segmentation from optical CT microscope images

    NASA Astrophysics Data System (ADS)

    Xie, Yiting; Reeves, Anthony P.

    2014-03-01

    The automated segmentation of the nucleus and cytoplasm regions in 3D optical CT microscope images has been achieved with two methods, a global threshold gradient based approach and a graph-cut approach. For the first method, the first two peaks of a gradient figure of merit curve are selected as the thresholds for cytoplasm and nucleus segmentation. The second method applies a graph-cut segmentation twice: the first identifies the nucleus region and the second identifies the cytoplasm region. Image segmentation of single cells is important for automated disease diagnostic systems. The segmentation methods were evaluated with 200 3D images consisting of 40 samples of 5 different cell types. The cell types consisted of columnar, macrophage, metaplastic and squamous human cells and cultured A549 cancer cells. The segmented cells were compared with both 2D and 3D reference images and the quality of segmentation was determined by the Dice Similarity Coefficient (DSC). In general, the graph-cut method had a superior performance to the gradient-based method. The graph-cut method achieved an average DSC of 86% and 72% for nucleus and cytoplasm segmentations respectively for the 2D reference images and 83% and 75% for the 3D reference images. The gradient method achieved an average DSC of 72% and 51% for nucleus and cytoplasm segmentation for the 2D reference images and 71% and 51% for the 3D reference images. The DSC of cytoplasm segmentation was significantly lower than for the nucleus since the cytoplasm was not differentiated as well by image intensity from the background.

  6. Pelvic CT scan

    MedlinePlus

    ... that slides into the center of the CT scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you. ... weight limit. Too much weight can damage the scanner's working parts. You will be asked to remove ...

  7. Parsing optical scanned 3D data by Bayesian inference

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Xu, Jun; Xu, Chenxi; Pan, Ming

    2015-10-01

    Optical devices are always used to digitize complex objects to get their shapes in form of point clouds. The results have no semantic meaning about the objects, and tedious process is indispensable to segment the scanned data to get meanings. The reason for a person to perceive an object correctly is the usage of knowledge, so Bayesian inference is used to the goal. A probabilistic And-Or-Graph is used as a unified framework of representation, learning, and recognition for a large number of object categories, and a probabilistic model defined on this And-Or-Graph is learned from a relatively small training set per category. Given a set of 3D scanned data, the Bayesian inference constructs a most probable interpretation of the object, and a semantic segment is obtained from the part decomposition. Some examples are given to explain the method.

  8. An omnidirectional 3D sensor with line laser scanning

    NASA Astrophysics Data System (ADS)

    Xu, Jing; Gao, Bingtuan; Liu, Chuande; Wang, Peng; Gao, Shuanglei

    2016-09-01

    An active omnidirectional vision owns the advantages of the wide field of view (FOV) imaging, resulting in an entire 3D environment scene, which is promising in the field of robot navigation. However, the existing omnidirectional vision sensors based on line laser can measure points only located on the optical plane of the line laser beam, resulting in the low-resolution reconstruction. Whereas, to improve resolution, some other omnidirectional vision sensors with the capability of projecting 2D encode pattern from projector and curved mirror. However, the astigmatism property of curve mirror causes the low-accuracy reconstruction. To solve the above problems, a rotating polygon scanning mirror is used to scan the object in the vertical direction so that an entire profile of the observed scene can be obtained at high accuracy, without of astigmatism phenomenon. Then, the proposed method is calibrated by a conventional 2D checkerboard plate. The experimental results show that the measurement error of the 3D omnidirectional sensor is approximately 1 mm. Moreover, the reconstruction of objects with different shapes based on the developed sensor is also verified.

  9. Accuracy assessment of 3D bone reconstructions using CT: an intro comparison.

    PubMed

    Lalone, Emily A; Willing, Ryan T; Shannon, Hannah L; King, Graham J W; Johnson, James A

    2015-08-01

    Computed tomography provides high contrast imaging of the joint anatomy and is used routinely to reconstruct 3D models of the osseous and cartilage geometry (CT arthrography) for use in the design of orthopedic implants, for computer assisted surgeries and computational dynamic and structural analysis. The objective of this study was to assess the accuracy of bone and cartilage surface model reconstructions by comparing reconstructed geometries with bone digitizations obtained using an optical tracking system. Bone surface digitizations obtained in this study determined the ground truth measure for the underlying geometry. We evaluated the use of a commercially available reconstruction technique using clinical CT scanning protocols using the elbow joint as an example of a surface with complex geometry. To assess the accuracies of the reconstructed models (8 fresh frozen cadaveric specimens) against the ground truth bony digitization-as defined by this study-proximity mapping was used to calculate residual error. The overall mean error was less than 0.4 mm in the cortical region and 0.3 mm in the subchondral region of the bone. Similarly creating 3D cartilage surface models from CT scans using air contrast had a mean error of less than 0.3 mm. Results from this study indicate that clinical CT scanning protocols and commonly used and commercially available reconstruction algorithms can create models which accurately represent the true geometry. PMID:26037323

  10. Children, CT Scan and Radiation

    PubMed Central

    Bajoghli, Morteza; Bajoghli, Farshad; Tayari, Nazila; Rouzbahani, Reza

    2010-01-01

    Children are more sensitive to radiation than adults. Computerized tomography (CT) consists of 25 % of all medical imaging. It was estimated that more than 2% of all carcinomas in the USA are due to CT scans. There is an ongoing focus on the reduction of CT scan radiation dose. Awareness about risk-benefits of CT has increased. Reduction of radiological exam is an important issue because the accumulation effects of radiation can be hazardous. In addition, proper protocol should be followed for diagnostic procedures of ionization radiation and computerized tomography. Effective radiation dose should range from 0.8 to 10.5 millisievert. The same protocol should be followed in different hospitals as well. Basic principles of radiation protection should be monitored. As much as possible, both technician and radiologist must be present during computerized tomography for children, and MRI and ultrasound should be replaced if possible. PMID:21566776

  11. TBIdoc: 3D content-based CT image retrieval system for traumatic brain injury

    NASA Astrophysics Data System (ADS)

    Li, Shimiao; Gong, Tianxia; Wang, Jie; Liu, Ruizhe; Tan, Chew Lim; Leong, Tze Yun; Pang, Boon Chuan; Lim, C. C. Tchoyoson; Lee, Cheng Kiang; Tian, Qi; Zhang, Zhuo

    2010-03-01

    Traumatic brain injury (TBI) is a major cause of death and disability. Computed Tomography (CT) scan is widely used in the diagnosis of TBI. Nowadays, large amount of TBI CT data is stacked in the hospital radiology department. Such data and the associated patient information contain valuable information for clinical diagnosis and outcome prediction. However, current hospital database system does not provide an efficient and intuitive tool for doctors to search out cases relevant to the current study case. In this paper, we present the TBIdoc system: a content-based image retrieval (CBIR) system which works on the TBI CT images. In this web-based system, user can query by uploading CT image slices from one study, retrieval result is a list of TBI cases ranked according to their 3D visual similarity to the query case. Specifically, cases of TBI CT images often present diffuse or focal lesions. In TBIdoc system, these pathological image features are represented as bin-based binary feature vectors. We use the Jaccard-Needham measure as the similarity measurement. Based on these, we propose a 3D similarity measure for computing the similarity score between two series of CT slices. nDCG is used to evaluate the system performance, which shows the system produces satisfactory retrieval results. The system is expected to improve the current hospital data management in TBI and to give better support for the clinical decision-making process. It may also contribute to the computer-aided education in TBI.

  12. Microstructure analysis of the secondary pulmonary lobules by 3D synchrotron radiation CT

    NASA Astrophysics Data System (ADS)

    Fukuoka, Y.; Kawata, Y.; Niki, N.; Umetani, K.; Nakano, Y.; Ohmatsu, H.; Moriyama, N.; Itoh, H.

    2014-03-01

    Recognition of abnormalities related to the lobular anatomy has become increasingly important in the diagnosis and differential diagnosis of lung abnormalities at clinical routines of CT examinations. This paper aims a 3-D microstructural analysis of the pulmonary acinus with isotropic spatial resolution in the range of several micrometers by using micro CT. Previously, we demonstrated the ability of synchrotron radiation micro CT (SRμCT) using offset scan mode in microstructural analysis of the whole part of the secondary pulmonary lobule. In this paper, we present a semiautomatic method to segment the acinar and subacinar airspaces from the secondary pulmonary lobule and to track small vessels running inside alveolar walls in human acinus imaged by the SRμCT. The method beains with and segmentation of the tissues such as pleural surface, interlobular septa, alveola wall, or vessel using a threshold technique and 3-D connected component analysis. 3-D air space are then conustructed separated by tissues and represented branching patterns of airways and airspaces distal to the terminal bronchiole. A graph-partitioning approach isolated acini whose stems are interactively defined as the terminal bronchiole in the secondary pulmonary lobule. Finally, we performed vessel tracking using a non-linear sate space which captures both smoothness of the trajectories and intensity coherence along vessel orientations. Results demonstrate that the proposed method can extract several acinar airspaces from the 3-D SRμCT image of secondary pulmonary lobule and that the extracted acinar airspace enable an accurate quantitative description of the anatomy of the human acinus for interpretation of the basic unit of pulmonary structure and function.

  13. 3D documentation and visualization of external injury findings by integration of simple photography in CT/MRI data sets (IprojeCT).

    PubMed

    Campana, Lorenzo; Breitbeck, Robert; Bauer-Kreuz, Regula; Buck, Ursula

    2016-05-01

    This study evaluated the feasibility of documenting patterned injury using three dimensions and true colour photography without complex 3D surface documentation methods. This method is based on a generated 3D surface model using radiologic slice images (CT) while the colour information is derived from photographs taken with commercially available cameras. The external patterned injuries were documented in 16 cases using digital photography as well as highly precise photogrammetry-supported 3D structured light scanning. The internal findings of these deceased were recorded using CT and MRI. For registration of the internal with the external data, two different types of radiographic markers were used and compared. The 3D surface model generated from CT slice images was linked with the photographs, and thereby digital true-colour 3D models of the patterned injuries could be created (Image projection onto CT/IprojeCT). In addition, these external models were merged with the models of the somatic interior. We demonstrated that 3D documentation and visualization of external injury findings by integration of digital photography in CT/MRI data sets is suitable for the 3D documentation of individual patterned injuries to a body. Nevertheless, this documentation method is not a substitution for photogrammetry and surface scanning, especially when the entire bodily surface is to be recorded in three dimensions including all external findings, and when precise data is required for comparing highly detailed injury features with the injury-inflicting tool. PMID:26496803

  14. Adaptive Iterative Dose Reduction Using Three Dimensional Processing (AIDR3D) Improves Chest CT Image Quality and Reduces Radiation Exposure

    PubMed Central

    Yamashiro, Tsuneo; Miyara, Tetsuhiro; Honda, Osamu; Kamiya, Hisashi; Murata, Kiyoshi; Ohno, Yoshiharu; Tomiyama, Noriyuki; Moriya, Hiroshi; Koyama, Mitsuhiro; Noma, Satoshi; Kamiya, Ayano; Tanaka, Yuko; Murayama, Sadayuki

    2014-01-01

    Objective To assess the advantages of Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) for image quality improvement and dose reduction for chest computed tomography (CT). Methods Institutional Review Boards approved this study and informed consent was obtained. Eighty-eight subjects underwent chest CT at five institutions using identical scanners and protocols. During a single visit, each subject was scanned using different tube currents: 240, 120, and 60 mA. Scan data were converted to images using AIDR3D and a conventional reconstruction mode (without AIDR3D). Using a 5-point scale from 1 (non-diagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for three lung zones, four patterns of lung disease (nodule/mass, emphysema, bronchiolitis, and diffuse lung disease), and three mediastinal measurements (small structure visibility, streak artifacts, and shoulder artifacts). Differences in these scores were assessed by Scheffe's test. Results At each tube current, scans using AIDR3D had higher scores than those without AIDR3D, which were significant for lung zones (p<0.0001) and all mediastinal measurements (p<0.01). For lung diseases, significant improvements with AIDR3D were frequently observed at 120 and 60 mA. Scans with AIDR3D at 120 mA had significantly higher scores than those without AIDR3D at 240 mA for lung zones and mediastinal streak artifacts (p<0.0001), and slightly higher or equal scores for all other measurements. Scans with AIDR3D at 60 mA were also judged superior or equivalent to those without AIDR3D at 120 mA. Conclusion For chest CT, AIDR3D provides better image quality and can reduce radiation exposure by 50%. PMID:25153797

  15. Characterization of a parallel beam CCD optical-CT apparatus for 3D radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Krstajić, Nikola; Doran, Simon J.

    2006-12-01

    This paper describes the initial steps we have taken in establishing CCD based optical-CT as a viable alternative for 3-D radiation dosimetry. First, we compare the optical density (OD) measurements from a high quality test target and variable neutral density filter (VNDF). A modulation transfer function (MTF) of individual projections is derived for three positions of the sinusoidal test target within the scanning tank. Our CCD is then characterized in terms of its signal-to-noise ratio (SNR). Finally, a sample reconstruction of a scan of a PRESAGETM (registered trademark of Heuris Pharma, NJ, Skillman, USA.) dosimeter is given, demonstrating the capabilities of the apparatus.

  16. Whole-body 3D scanner and scan data report

    NASA Astrophysics Data System (ADS)

    Addleman, Stephen R.

    1997-03-01

    With the first whole-body 3D scanner now available the next adventure confronting the user is what to do with all of the data. While the system was built for anthropologists, it has created interest among users from a wide variety of fields. Users with applications in the fields of anthropology, costume design, garment design, entertainment, VR and gaming have a need for the data in formats unique to their fields. Data from the scanner is being converted to solid models for art and design and NURBS for computer graphics applications. Motion capture has made scan data move and dance. The scanner has created a need for advanced application software just as other scanners have in the past.

  17. 3D automatic liver segmentation using feature-constrained Mahalanobis distance in CT images.

    PubMed

    Salman Al-Shaikhli, Saif Dawood; Yang, Michael Ying; Rosenhahn, Bodo

    2016-08-01

    Automatic 3D liver segmentation is a fundamental step in the liver disease diagnosis and surgery planning. This paper presents a novel fully automatic algorithm for 3D liver segmentation in clinical 3D computed tomography (CT) images. Based on image features, we propose a new Mahalanobis distance cost function using an active shape model (ASM). We call our method MD-ASM. Unlike the standard active shape model (ST-ASM), the proposed method introduces a new feature-constrained Mahalanobis distance cost function to measure the distance between the generated shape during the iterative step and the mean shape model. The proposed Mahalanobis distance function is learned from a public database of liver segmentation challenge (MICCAI-SLiver07). As a refinement step, we propose the use of a 3D graph-cut segmentation. Foreground and background labels are automatically selected using texture features of the learned Mahalanobis distance. Quantitatively, the proposed method is evaluated using two clinical 3D CT scan databases (MICCAI-SLiver07 and MIDAS). The evaluation of the MICCAI-SLiver07 database is obtained by the challenge organizers using five different metric scores. The experimental results demonstrate the availability of the proposed method by achieving an accurate liver segmentation compared to the state-of-the-art methods. PMID:26501155

  18. 3D body scanning technology for fashion and apparel industry

    NASA Astrophysics Data System (ADS)

    D'Apuzzo, Nicola

    2007-01-01

    This paper presents an overview of 3D body scanning technologies with applications to the fashion and apparel industry. Complete systems for the digitization of the human body exist since more than fifteen years. One of the main users of this technology with application in the textile field was the military industry. In fact, body scanning technology is being successfully employed since many years in military bases for a fast selection of the correct size of uniforms for the entire staff. Complete solutions were especially developed for this field of application. Many different research projects were issued for the exploitation of the same technology in the commercial field. Experiments were performed and start-up projects are to time running in different parts of the world by installing full body scanning systems in various locations such as shopping malls, boutiques or dedicated scanning centers. Everything is actually ready to be exploited and all the required hardware, software and solutions are available: full body scanning systems, software for the automatic and reliable extraction of body measurements, e-kiosk and web solutions for the presentation of garments, high-end and low-end virtual-try-on systems. However, complete solutions in this area have still not yet found the expected commercial success. Today, with the on-going large cost reduction given by the appearance of new competitors, methods for digitization of the human body becomes more interesting for the fashion and apparel industry. Therefore, a large expansion of these technologies is expected in the near future. To date, different methods are used commercially for the measurement of the human body. These can be divided into three major distinguished groups: laser-scanning, projection of light patterns, combination modeling and image processing. The different solutions have strengths and weaknesses that profile their suitability for specific applications. This paper gives an overview of their

  19. SU-E-J-209: Verification of 3D Surface Registration Between Stereograms and CT Images

    SciTech Connect

    Han, T; Gifford, K; Smith, B; Salehpour, M

    2014-06-01

    Purpose: Stereography can provide a visualization of the skin surface for radiation therapy patients. The aim of this study was to verify the registration algorithm in a commercial image analysis software, 3dMDVultus, for the fusion of stereograms and CT images. Methods: CT and stereographic scans were acquired of a head phantom and a deformable phantom. CT images were imported in 3dMDVultus and the surface contours were generated by threshold segmentation. Stereograms were reconstructed in 3dMDVultus. The resulting surfaces were registered with Vultus algorithm and then exported to in-house registration software and compared with four algorithms: rigid, affine, non-rigid iterative closest point (ICP) and b-spline algorithm. RMS (root-mean-square residuals of the surface point distances) error between the registered CT and stereogram surfaces was calculated and analyzed. Results: For the head phantom, the maximum RMS error between registered CT surfaces to stereogram was 6.6 mm for Vultus algorithm, whereas the mean RMS error was 0.7 mm. For the deformable phantom, the maximum RMS error was 16.2 mm for Vultus algorithm, whereas the mean RMS error was 4.4 mm. Non-rigid ICP demonstrated the best registration accuracy, as the mean of RMS errors were both within 1 mm. Conclusion: The accuracy of registration algorithm in 3dMDVultus was verified and exceeded RMS of 2 mm for deformable cases. Non-rigid ICP and b-spline algorithms improve the registration accuracy for both phantoms, especially in deformable one. For those patients whose body habitus deforms during radiation therapy, more advanced nonrigid algorithms need to be used.

  20. Photon counting x-ray CT with 3D holograms by CdTe line sensor

    NASA Astrophysics Data System (ADS)

    Koike, A.; Yomori, M.; Morii, H.; Neo, Y.; Aoki, T.; Mimura, H.

    2008-08-01

    The novel 3-D display system is required in the medical treatment field and non-destructive testing field. In these field, the X-ray CT system is used for obtaining 3-D information. However, there are no meaningful 3-D information in X-ray CT data, and there are also no practical 3-D display system. Therefore, in this paper, we propose an X-ray 3-D CT display system by combining a photon-counting X-ray CT system and a holographic image display system. The advantage of this system was demonstrated by comparing the holographic calculation time and recognizability of a reconstructed image.

  1. Scanning fringe projection for fast 3D inspection

    NASA Astrophysics Data System (ADS)

    Honegger, Marc; Kahl, Michael; Trunz, Sandra; Rinner, Stefan; Ettemeyer, Andreas; Lambelet, Patrick

    2013-04-01

    In an earlier paper we have described a concept for high speed 3D inspection using fringe projection techniques. We use a special CMOS camera with 300 x 300 px which can calculate the phase on board. The focus of the first step of development had been a fringe projector, which was able to modulate the projected fringes with up to 250 kHz. In the second step the image acquisition part of the system was developed. In case of 3D measurement with a matrix camera, the camera resp. the measuring object has to be moved stepwise in the lateral direction to cover multiple acquisition areas of the measurement object. Between each image the lateral movement has to correspond to the field of view of the camera. At the intended very high image acquisition rates the high acceleration of the system between each image will lead to inacceptable mechanical forces. In order to obtain a continuous scanning procedure and at the same time to use the performance of a matrix camera, a special lens system was developed. A measurement field 120 mm long and 3 mm wide is imaged onto the camera. The width of the measuring field is imaged onto the 300 rows of the camera, giving a lateral resolution of 10 μm. In the longitudinal direction the 120 mm object length is divided into 12'000 lines to reach the same resolution of 10 μm. Due to technical reasons that will be described later only 240 of the 300 pixel rows on the chip were used. Consequently, with each camera shot 240 separated lines are imaged onto the chip. Between each of these 240 lines there is a large empty space, which is not imaged by the camera. In principle, the camera is operating as 240 single line cameras. Therefore, if the camera is shifted in an inclined direction to the camera orientation over the object, the empty spaces can be recorded as well. In an optimum alignment, the complete measuring object can be scanned in a continuous movement, covering the total length of 120 mm. In this paper we will describe this image

  2. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    PubMed Central

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-01-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images. PMID:26980176

  3. Improving Low-dose Cardiac CT Images based on 3D Sparse Representation

    NASA Astrophysics Data System (ADS)

    Shi, Luyao; Hu, Yining; Chen, Yang; Yin, Xindao; Shu, Huazhong; Luo, Limin; Coatrieux, Jean-Louis

    2016-03-01

    Cardiac computed tomography (CCT) is a reliable and accurate tool for diagnosis of coronary artery diseases and is also frequently used in surgery guidance. Low-dose scans should be considered in order to alleviate the harm to patients caused by X-ray radiation. However, low dose CT (LDCT) images tend to be degraded by quantum noise and streak artifacts. In order to improve the cardiac LDCT image quality, a 3D sparse representation-based processing (3D SR) is proposed by exploiting the sparsity and regularity of 3D anatomical features in CCT. The proposed method was evaluated by a clinical study of 14 patients. The performance of the proposed method was compared to the 2D spares representation-based processing (2D SR) and the state-of-the-art noise reduction algorithm BM4D. The visual assessment, quantitative assessment and qualitative assessment results show that the proposed approach can lead to effective noise/artifact suppression and detail preservation. Compared to the other two tested methods, 3D SR method can obtain results with image quality most close to the reference standard dose CT (SDCT) images.

  4. High-resolution 3D micro-CT imaging of breast microcalcifications: a preliminary analysis

    PubMed Central

    2014-01-01

    Background Detection of microcalcifications on mammograms indicates the presence of breast lesion, and the shapes of the microcalcifications as seen by conventional mammography correlates with the probability of malignancy. This preliminary study evaluated the 3D shape of breast microcalcifications using micro-computed tomography (micro-CT) and compared the findings with those obtained using anatomopathological analysis. Methods The study analyzed breast biopsy samples from 11 women with findings of suspicious microcalcifications on routine mammograms. The samples were imaged using a micro-CT (SkyScan 1076) at a resolution of 35 μm. Images were reconstructed using filtered back-projection and analyzed in 3D using surface rendering. The samples were subsequently analyzed by the pathology service. Reconstructed 3D images were compared with the corresponding histological slices. Results Anatomopathological analysis showed that 5 of 11 patients had ductal breast carcinoma in situ. One patient was diagnosed with invasive ductal carcinoma. Individual object analysis was performed on 597 microcalcifications. Malignant microcalcifications tended to be thinner and to have a smaller volume and surface area, while their surface area-to-volume ratio was greater than that of benign microcalcifications. The structure model index values were the same for malignant and benign microcalcifications. Conclusions This is the first study to use micro-CT for quantitative 3D analysis of microcalcifications. This high-resolution imaging technique will be valuable for gaining a greater understanding of the morphologic characteristics of malignant and benign microcalcifications. The presence of many small microcalcifications can be an indication of malignancy. For the larger microcalcifications, 3D parameters confirmed the more irregular shape of malignant microcalcifications. PMID:24393444

  5. Effects of scanning orientation on outlier formation in 3D laser scanning of reflective surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Yutao; Feng, Hsi-Yung

    2016-06-01

    Inspecting objects with reflective surfaces using 3D laser scanning is a demanded but challenging part inspection task due to undesirable specular reflections, which produce extensive outliers in the scanned point cloud. These outliers need to be removed in order to alleviate subsequent data processing issues. Many existing automatic outlier removal methods do not detect outliers according to the outlier formation properties. As a result, these methods only offer limited capabilities in removing extensive and complex outliers from scanning objects with reflective surfaces. This paper reports an empirical study which experimentally investigates the outlier formation characteristics in relation to the scanning orientation of the laser probe. The objective is to characterize the scanning orientation effects on outlier formation in order to facilitate the development of an effective outlier detection and removal method. Such an experimental investigation was hardly done before. It has been found in this work that scanning orientation can directly affect outlier extensity and occurrence in 3D laser scanning. A general guidance on proper scan path planning can then be provided with an aim to reduce the occurrence of outliers. Further, the observed dependency of outlier formation on scanning orientation can be exploited to facilitate effective and automatic outlier detection and removal.

  6. How effective can optical-CT 3D dosimetry be without refractive fluid matching?

    NASA Astrophysics Data System (ADS)

    Rankine, L.; Oldham

    2013-06-01

    Achieving accurate optical CT 3D dosimetry without the use of viscous refractive index (RI) matching fluids would greatly increase convenience. Software has been developed to simulate optical CT 3D dosimetry for a range of scanning configurations including parallel-beam, point and converging light sources. For each configuration the efficacy of 3 refractive media were investigated: air, water, and a fluid closely matched to Presage (RI = 1.00, 1.33 and 1.49 respectively). The results revealed that the useable radius of the dosimeter (i.e. where data was within 2% of truth) reduced to 68% for water-matching, and 31% for dry-scanning in air. Point source incident ray geometry produced slightly more favourable results, although variation between the three geometries was relatively small. The required detector size however, increased by a factor six for dry-scanning, introducing cost penalties. For applications where dose information is not required in the periphery, some dry and low-viscous matching configurations may be feasible.

  7. 3D imaging by serial block face scanning electron microscopy for materials science using ultramicrotomy.

    PubMed

    Hashimoto, Teruo; Thompson, George E; Zhou, Xiaorong; Withers, Philip J

    2016-04-01

    Mechanical serial block face scanning electron microscopy (SBFSEM) has emerged as a means of obtaining three dimensional (3D) electron images over volumes much larger than possible by focused ion beam (FIB) serial sectioning and at higher spatial resolution than achievable with conventional X-ray computed tomography (CT). Such high resolution 3D electron images can be employed for precisely determining the shape, volume fraction, distribution and connectivity of important microstructural features. While soft (fixed or frozen) biological samples are particularly well suited for nanoscale sectioning using an ultramicrotome, the technique can also produce excellent 3D images at electron microscope resolution in a time and resource-efficient manner for engineering materials. Currently, a lack of appreciation of the capabilities of ultramicrotomy and the operational challenges associated with minimising artefacts for different materials is limiting its wider application to engineering materials. Consequently, this paper outlines the current state of the art for SBFSEM examining in detail how damage is introduced during slicing and highlighting strategies for minimising such damage. A particular focus of the study is the acquisition of 3D images for a variety of metallic and coated systems. PMID:26855205

  8. CT based 3D Monte Carlo radiation therapy treatment planning.

    PubMed

    Wallace, S; Allen, B J

    1998-06-01

    This paper outlines the "voxel reconstruction" technique used to model the macroscopic human anatomy of the cranial, abdominal and cervical regions directly from CT scans. Tissue composition, density, and radiation transport characteristics were assigned to each individual volume element (voxel) automatically depending on its greyscale number and physical location. Both external beam and brachytherapy treatment techniques were simulated using the Monte Carlo radiation transport code MCNP (Monte Carlo N-Particle) version 3A. To obtain a high resolution dose calculation, yet not overly extend computational times, variable voxel sizes have been introduced. In regions of interest where high attention to anatomical detail and dose calculation was required, the voxel dimensions were reduced to a few millimetres. In less important regions that only influence the region of interest via scattered radiation, the voxel dimensions were increased to the scale of centimetres. With the use of relatively old (1991) supercomputing hardware, dose calculations were performed in under 10 hours to a standard deviation of 5% in each voxel with a resolution of a few millimetres--current hardware should substantially improve these figures. It is envisaged that with coupled photon/electron transport incorporated into MCNP version 4A and 4B, conventional photon and electron treatment planning will be undertaken using this technique, in addition to neutron and associated photon dosimetry presented here. PMID:9745789

  9. Automated 3D reconstruction of interiors with multiple scan views

    NASA Astrophysics Data System (ADS)

    Sequeira, Vitor; Ng, Kia C.; Wolfart, Erik; Goncalves, Joao G. M.; Hogg, David C.

    1998-12-01

    This paper presents two integrated solutions for realistic 3D model acquisition and reconstruction; an early prototype, in the form of a push trolley, and a later prototype in the form of an autonomous robot. The systems encompass all hardware and software required, from laser and video data acquisition, processing and output of texture-mapped 3D models in VRML format, to batteries for power supply and wireless network communications. The autonomous version is also equipped with a mobile platform and other sensors for the purpose of automatic navigation. The applications for such a system range from real estate and tourism (e.g., showing a 3D computer model of a property to a potential buyer or tenant) or as tool for content creation (e.g., creating 3D models of heritage buildings or producing broadcast quality virtual studios). The system can also be used in industrial environments as a reverse engineering tool to update the design of a plant, or as a 3D photo-archive for insurance purposes. The system is Internet compatible: the photo-realistic models can be accessed via the Internet and manipulated interactively in 3D using a common Web browser with a VRML plug-in. Further information and example reconstructed models are available on- line via the RESOLV web-page at http://www.scs.leeds.ac.uk/resolv/.

  10. 3D scanning of internal structure in gel engineering materials with visual scanning microscopic light scattering

    NASA Astrophysics Data System (ADS)

    Watanabe, Yosuke; Gong, Jing; Masato, Makino; Kabir, M. Hasnat; Furukawa, Hidemitsu

    2014-04-01

    The 3D printing technology, causing much attention from the beginning of 2013, will be possibly an alternative method to fabricate the biological soft tissues. Recently our group of Yamagata University has developed the world-first 3D Gel Printer to fabricate the complicated gel-materials with high-strength and biocompatibility. However, there are no 3D scanners that collect the data from the internal structure of complicated gel objects such as eye lens. It means that a new system for scanning the internal structure is needed now. In this study, firstly, we have tried to investigate the gel network of synthetic and biological gel with scanning microscopic light scattering (SMILS). We calculated the Young's modulus of synthetic gels with the SMILS and with the tensile test, and precisely compared the results between them. The temperature dependences of the inside structure and the transparency are observed in the pig crystalline lens. The quantitative analysis indicates the importance of the internal structure of real object. Secondary, we show the new system named Gel-scanner that can provide the 2-dimentional data of the internal structure. From examining our findings, the scanning of internal structure will enable us to expect physical properties of the real object. We convince that the gelscanner will play major role in the various fields.

  11. Development of a 3D printer using scanning projection stereolithography

    PubMed Central

    Lee, Michael P.; Cooper, Geoffrey J. T.; Hinkley, Trevor; Gibson, Graham M.; Padgett, Miles J.; Cronin, Leroy

    2015-01-01

    We have developed a system for the rapid fabrication of low cost 3D devices and systems in the laboratory with micro-scale features yet cm-scale objects. Our system is inspired by maskless lithography, where a digital micromirror device (DMD) is used to project patterns with resolution up to 10 µm onto a layer of photoresist. Large area objects can be fabricated by stitching projected images over a 5cm2 area. The addition of a z-stage allows multiple layers to be stacked to create 3D objects, removing the need for any developing or etching steps but at the same time leading to true 3D devices which are robust, configurable and scalable. We demonstrate the applications of the system by printing a range of micro-scale objects as well as a fully functioning microfluidic droplet device and test its integrity by pumping dye through the channels. PMID:25906401

  12. The use of 3D scanning for sporting applications

    NASA Astrophysics Data System (ADS)

    Friel, Kevin; Ajjimaporn, Pann; Straub, Jeremy; Kerlin, Scott

    2015-05-01

    This paper describes the process and research that went into creating a set of 3D models to characterize a golf swing. The purpose of this work is to illustrate how a 3D scanner could be used for assessing athlete performance in sporting applications. In this case, introductory work has been performed to show how the scanner could be used to show the errors a golfer made in a swing. Multiple factors must be taken into account when assessing golfers' swings including the position and movement of the golfer's hands, arms, and foot placement as well as the position of the club head and shaft of the golf club.

  13. Visualization of 3D osteon morphology by synchrotron radiation micro-CT

    PubMed Central

    Cooper, D M L; Erickson, B; Peele, A G; Hannah, K; Thomas, C D L; Clement, J G

    2011-01-01

    Cortical bone histology has been the subject of scientific inquiry since the advent of the earliest microscopes. Histology – literally the study of tissue – is a field nearly synonymous with 2D thin sections. That said, progressive developments in high-resolution X-ray imaging are enabling 3D visualization to reach ever smaller structures. Micro-computed tomography (micro-CT), employing conventional X-ray sources, has become the gold standard for 3D analysis of trabecular bone and is capable of detecting the structure of vascular (osteonal) porosity in cortical bone. To date, however, direct 3D visualization of secondary osteons has eluded micro-CT based upon absorption-derived contrast. Synchrotron radiation micro-CT, through greater image quality, resolution and alternative contrast mechanisms (e.g. phase contrast), holds great potential for non-destructive 3D visualization of secondary osteons. Our objective was to demonstrate this potential and to discuss areas of bone research that can be advanced through the application of this approach. We imaged human mid-femoral cortical bone specimens derived from a 20-year-old male (Melbourne Femur Collection) at the Advanced Photon Source synchrotron (Chicago, IL, USA) using the 2BM beam line. A 60-mm distance between the target and the detector was employed to enhance visualization of internal structures through propagation phase contrast. Scan times were 1 h and images were acquired with 1.4-μm nominal isotropic resolution. Computer-aided manual segmentation and volumetric 3D rendering were employed to visualize secondary osteons and porous structures, respectively. Osteonal borders were evident via two contrast mechanisms. First, relatively new (hypomineralized) osteons were evident due to differences in X-ray attenuation relative to the surrounding bone. Second, osteon boundaries (cement lines) were delineated by phase contrast. Phase contrast also enabled the detection of soft tissue remnants within the

  14. Chest wall segmentation in automated 3D breast ultrasound scans.

    PubMed

    Tan, Tao; Platel, Bram; Mann, Ritse M; Huisman, Henkjan; Karssemeijer, Nico

    2013-12-01

    In this paper, we present an automatic method to segment the chest wall in automated 3D breast ultrasound images. Determining the location of the chest wall in automated 3D breast ultrasound images is necessary in computer-aided detection systems to remove automatically detected cancer candidates beyond the chest wall and it can be of great help for inter- and intra-modal image registration. We show that the visible part of the chest wall in an automated 3D breast ultrasound image can be accurately modeled by a cylinder. We fit the surface of our cylinder model to a set of automatically detected rib-surface points. The detection of the rib-surface points is done by a classifier using features representing local image intensity patterns and presence of rib shadows. Due to attenuation of the ultrasound signal, a clear shadow is visible behind the ribs. Evaluation of our segmentation method is done by computing the distance of manually annotated rib points to the surface of the automatically detected chest wall. We examined the performance on images obtained with the two most common 3D breast ultrasound devices in the market. In a dataset of 142 images, the average mean distance of the annotated points to the segmented chest wall was 5.59 ± 3.08 mm. PMID:23273891

  15. 3D statistical shape models incorporating 3D random forest regression voting for robust CT liver segmentation

    NASA Astrophysics Data System (ADS)

    Norajitra, Tobias; Meinzer, Hans-Peter; Maier-Hein, Klaus H.

    2015-03-01

    During image segmentation, 3D Statistical Shape Models (SSM) usually conduct a limited search for target landmarks within one-dimensional search profiles perpendicular to the model surface. In addition, landmark appearance is modeled only locally based on linear profiles and weak learners, altogether leading to segmentation errors from landmark ambiguities and limited search coverage. We present a new method for 3D SSM segmentation based on 3D Random Forest Regression Voting. For each surface landmark, a Random Regression Forest is trained that learns a 3D spatial displacement function between the according reference landmark and a set of surrounding sample points, based on an infinite set of non-local randomized 3D Haar-like features. Landmark search is then conducted omni-directionally within 3D search spaces, where voxelwise forest predictions on landmark position contribute to a common voting map which reflects the overall position estimate. Segmentation experiments were conducted on a set of 45 CT volumes of the human liver, of which 40 images were randomly chosen for training and 5 for testing. Without parameter optimization, using a simple candidate selection and a single resolution approach, excellent results were achieved, while faster convergence and better concavity segmentation were observed, altogether underlining the potential of our approach in terms of increased robustness from distinct landmark detection and from better search coverage.

  16. 3D scanning and 3D printing as innovative technologies for fabricating personalized topical drug delivery systems.

    PubMed

    Goyanes, Alvaro; Det-Amornrat, Usanee; Wang, Jie; Basit, Abdul W; Gaisford, Simon

    2016-07-28

    Acne is a multifactorial inflammatory skin disease with high prevalence. In this work, the potential of 3D printing to produce flexible personalised-shape anti-acne drug (salicylic acid) loaded devices was demonstrated by two different 3D printing (3DP) technologies: Fused Deposition Modelling (FDM) and stereolithography (SLA). 3D scanning technology was used to obtain a 3D model of a nose adapted to the morphology of an individual. In FDM 3DP, commercially produced Flex EcoPLA™ (FPLA) and polycaprolactone (PCL) filaments were loaded with salicylic acid by hot melt extrusion (HME) (theoretical drug loading - 2% w/w) and used as feedstock material for 3D printing. Drug loading in the FPLA-salicylic acid and PCL-salicylic acid 3D printed patches was 0.4% w/w and 1.2% w/w respectively, indicating significant thermal degradation of drug during HME and 3D printing. Diffusion testing in Franz cells using a synthetic membrane revealed that the drug loaded printed samples released <187μg/cm(2) within 3h. FPLA-salicylic acid filament was successfully printed as a nose-shape mask by FDM 3DP, but the PCL-salicylic acid filament was not. In the SLA printing process, the drug was dissolved in different mixtures of poly(ethylene glycol) diacrylate (PEGDA) and poly(ethylene glycol) (PEG) that were solidified by the action of a laser beam. SLA printing led to 3D printed devices (nose-shape) with higher resolution and higher drug loading (1.9% w/w) than FDM, with no drug degradation. The results of drug diffusion tests revealed that drug diffusion was faster than with the FDM devices, 229 and 291μg/cm(2) within 3h for the two formulations evaluated. In this study, SLA printing was the more appropriate 3D printing technology to manufacture anti-acne devices with salicylic acid. The combination of 3D scanning and 3D printing has the potential to offer solutions to produce personalised drug loaded devices, adapted in shape and size to individual patients. PMID:27189134

  17. Accuracy of volume measurement using 3D ultrasound and development of CT-3D US image fusion algorithm for prostate cancer radiotherapy

    SciTech Connect

    Baek, Jihye; Huh, Jangyoung; Hyun An, So; Oh, Yoonjin; Kim, Myungsoo; Kim, DongYoung; Chung, Kwangzoo; Cho, Sungho; Lee, Rena

    2013-02-15

    Purpose: To evaluate the accuracy of measuring volumes using three-dimensional ultrasound (3D US), and to verify the feasibility of the replacement of CT-MR fusion images with CT-3D US in radiotherapy treatment planning. Methods: Phantoms, consisting of water, contrast agent, and agarose, were manufactured. The volume was measured using 3D US, CT, and MR devices. A CT-3D US and MR-3D US image fusion software was developed using the Insight Toolkit library in order to acquire three-dimensional fusion images. The quality of the image fusion was evaluated using metric value and fusion images. Results: Volume measurement, using 3D US, shows a 2.8 {+-} 1.5% error, 4.4 {+-} 3.0% error for CT, and 3.1 {+-} 2.0% error for MR. The results imply that volume measurement using the 3D US devices has a similar accuracy level to that of CT and MR. Three-dimensional image fusion of CT-3D US and MR-3D US was successfully performed using phantom images. Moreover, MR-3D US image fusion was performed using human bladder images. Conclusions: 3D US could be used in the volume measurement of human bladders and prostates. CT-3D US image fusion could be used in monitoring the target position in each fraction of external beam radiation therapy. Moreover, the feasibility of replacing the CT-MR image fusion to the CT-3D US in radiotherapy treatment planning was verified.

  18. Algorithm of pulmonary emphysema extraction using thoracic 3D CT images

    NASA Astrophysics Data System (ADS)

    Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

    2007-03-01

    Recently, due to aging and smoking, emphysema patients are increasing. The restoration of alveolus which was destroyed by emphysema is not possible, thus early detection of emphysema is desired. We describe a quantitative algorithm for extracting emphysematous lesions and quantitatively evaluate their distribution patterns using low dose thoracic 3-D CT images. The algorithm identified lung anatomies, and extracted low attenuation area (LAA) as emphysematous lesion candidates. Applying the algorithm to thoracic 3-D CT images and then by follow-up 3-D CT images, we demonstrate its potential effectiveness to assist radiologists and physicians to quantitatively evaluate the emphysematous lesions distribution and their evolution in time interval changes.

  19. Algorithm of pulmonary emphysema extraction using low dose thoracic 3D CT images

    NASA Astrophysics Data System (ADS)

    Saita, S.; Kubo, M.; Kawata, Y.; Niki, N.; Nakano, Y.; Omatsu, H.; Tominaga, K.; Eguchi, K.; Moriyama, N.

    2006-03-01

    Recently, due to aging and smoking, emphysema patients are increasing. The restoration of alveolus which was destroyed by emphysema is not possible, thus early detection of emphysema is desired. We describe a quantitative algorithm for extracting emphysematous lesions and quantitatively evaluate their distribution patterns using low dose thoracic 3-D CT images. The algorithm identified lung anatomies, and extracted low attenuation area (LAA) as emphysematous lesion candidates. Applying the algorithm to 100 thoracic 3-D CT images and then by follow-up 3-D CT images, we demonstrate its potential effectiveness to assist radiologists and physicians to quantitatively evaluate the emphysematous lesions distribution and their evolution in time interval changes.

  20. Segmentation of the ovine lung in 3D CT Images

    NASA Astrophysics Data System (ADS)

    Shi, Lijun; Hoffman, Eric A.; Reinhardt, Joseph M.

    2004-04-01

    Pulmonary CT images can provide detailed information about the regional structure and function of the respiratory system. Prior to any of these analyses, however, the lungs must be identified in the CT data sets. A popular animal model for understanding lung physiology and pathophysiology is the sheep. In this paper we describe a lung segmentation algorithm for CT images of sheep. The algorithm has two main steps. The first step is lung extraction, which identifies the lung region using a technique based on optimal thresholding and connected components analysis. The second step is lung separation, which separates the left lung from the right lung by identifying the central fissure using an anatomy-based method incorporating dynamic programming and a line filter algorithm. The lung segmentation algorithm has been validated by comparing our automatic method to manual analysis for five pulmonary CT datasets. The RMS error between the computer-defined and manually-traced boundary is 0.96 mm. The segmentation requires approximately 10 minutes for a 512x512x400 dataset on a PC workstation (2.40 GHZ CPU, 2.0 GB RAM), while it takes human observer approximately two hours to accomplish the same task.

  1. Regularization Designs for Uniform Spatial Resolution and Noise Properties in Statistical Image Reconstruction for 3D X-ray CT

    PubMed Central

    Cho, Jang Hwan; Fessler, Jeffrey A.

    2014-01-01

    Statistical image reconstruction methods for X-ray computed tomography (CT) provide improved spatial resolution and noise properties over conventional filtered back-projection (FBP) reconstruction, along with other potential advantages such as reduced patient dose and artifacts. Conventional regularized image reconstruction leads to spatially variant spatial resolution and noise characteristics because of interactions between the system models and the regularization. Previous regularization design methods aiming to solve such issues mostly rely on circulant approximations of the Fisher information matrix that are very inaccurate for undersampled geometries like short-scan cone-beam CT. This paper extends the regularization method proposed in [1] to 3D cone-beam CT by introducing a hypothetical scanning geometry that helps address the sampling properties. The proposed regularization designs were compared with the original method in [1] with both phantom simulation and clinical reconstruction in 3D axial X-ray CT. The proposed regularization methods yield improved spatial resolution or noise uniformity in statistical image reconstruction for short-scan axial cone-beam CT. PMID:25361500

  2. 3D Ultrasound Can Contribute to Planning CT to Define the Target for Partial Breast Radiotherapy

    SciTech Connect

    Berrang, Tanya S.; Truong, Pauline T. Popescu, Carmen; Drever, Laura; Kader, Hosam A.; Hilts, Michelle L.; Mitchell, Tracy; Soh, S.Y.; Sands, Letricia; Silver, Stuart; Olivotto, Ivo A.

    2009-02-01

    Purpose: The role of three-dimensional breast ultrasound (3D US) in planning partial breast radiotherapy (PBRT) is unknown. This study evaluated the accuracy of coregistration of 3D US to planning computerized tomography (CT) images, the seroma contouring consistency of radiation oncologists using the two imaging modalities and the clinical situations in which US was associated with improved contouring consistency compared to CT. Materials and Methods: Twenty consecutive women with early-stage breast cancer were enrolled prospectively after breast-conserving surgery. Subjects underwent 3D US at CT simulation for adjuvant RT. Three radiation oncologists independently contoured the seroma on separate CT and 3D US image sets. Seroma clarity, seroma volumes, and interobserver contouring consistency were compared between the imaging modalities. Associations between clinical characteristics and seroma clarity were examined using Pearson correlation statistics. Results: 3D US and CT coregistration was accurate to within 2 mm or less in 19/20 (95%) cases. CT seroma clarity was reduced with dense breast parenchyma (p = 0.035), small seroma volume (p < 0.001), and small volume of excised breast tissue (p = 0.01). US seroma clarity was not affected by these factors (p = NS). US was associated with improved interobserver consistency compared with CT in 8/20 (40%) cases. Of these 8 cases, 7 had low CT seroma clarity scores and 4 had heterogeneously to extremely dense breast parenchyma. Conclusion: 3D US can be a useful adjunct to CT in planning PBRT. Radiation oncologists were able to use US images to contour the seroma target, with improved interobserver consistency compared with CT in cases with dense breast parenchyma and poor CT seroma clarity.

  3. Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid.

    PubMed

    Bache, Steven; Malcolm, Javian; Adamovics, John; Oldham, Mark

    2016-01-01

    Telecentric optical computed tomography (optical-CT) is a state-of-the-art method for visualizing and quantifying 3-dimensional dose distributions in radiochromic dosimeters. In this work a prototype telecentric system (DFOS-Duke Fresnel Optical-CT Scanner) is evaluated which incorporates two substantial design changes: the use of Fresnel lenses (reducing lens costs from $10-30K t0 $1-3K) and the use of a 'solid tank' (which reduces noise, and the volume of refractively matched fluid from 1 ltr to 10 cc). The efficacy of DFOS was evaluated by direct comparison against commissioned scanners in our lab. Measured dose distributions from all systems were compared against the predicted dose distributions from a commissioned treatment planning system (TPS). Three treatment plans were investigated including a simple four-field box treatment, a multiple small field delivery, and a complex IMRT treatment. Dosimeters were imaged within 2 h post irradiation, using consistent scanning techniques (360 projections acquired at 1 degree intervals, reconstruction at 2mm). DFOS efficacy was evaluated through inspection of dose line-profiles, and 2D and 3D dose and gamma maps. DFOS/TPS gamma pass rates with 3%/3mm dose difference/distance-to-agreement criteria ranged from 89.3% to 92.2%, compared to from 95.6% to 99.0% obtained with the commissioned system. The 3D gamma pass rate between the commissioned system and DFOS was 98.2%. The typical noise rates in DFOS reconstructions were up to 3%, compared to under 2% for the commissioned system. In conclusion, while the introduction of a solid tank proved advantageous with regards to cost and convenience, further work is required to improve the image quality and dose reconstruction accuracy of the new DFOS optical-CT system. PMID:27019460

  4. Optical-CT 3D Dosimetry Using Fresnel Lenses with Minimal Refractive-Index Matching Fluid

    PubMed Central

    Bache, Steven; Malcolm, Javian; Adamovics, John; Oldham, Mark

    2016-01-01

    Telecentric optical computed tomography (optical-CT) is a state-of-the-art method for visualizing and quantifying 3-dimensional dose distributions in radiochromic dosimeters. In this work a prototype telecentric system (DFOS—Duke Fresnel Optical-CT Scanner) is evaluated which incorporates two substantial design changes: the use of Fresnel lenses (reducing lens costs from $10-30K t0 $1-3K) and the use of a ‘solid tank’ (which reduces noise, and the volume of refractively matched fluid from 1ltr to 10cc). The efficacy of DFOS was evaluated by direct comparison against commissioned scanners in our lab. Measured dose distributions from all systems were compared against the predicted dose distributions from a commissioned treatment planning system (TPS). Three treatment plans were investigated including a simple four-field box treatment, a multiple small field delivery, and a complex IMRT treatment. Dosimeters were imaged within 2h post irradiation, using consistent scanning techniques (360 projections acquired at 1 degree intervals, reconstruction at 2mm). DFOS efficacy was evaluated through inspection of dose line-profiles, and 2D and 3D dose and gamma maps. DFOS/TPS gamma pass rates with 3%/3mm dose difference/distance-to-agreement criteria ranged from 89.3% to 92.2%, compared to from 95.6% to 99.0% obtained with the commissioned system. The 3D gamma pass rate between the commissioned system and DFOS was 98.2%. The typical noise rates in DFOS reconstructions were up to 3%, compared to under 2% for the commissioned system. In conclusion, while the introduction of a solid tank proved advantageous with regards to cost and convenience, further work is required to improve the image quality and dose reconstruction accuracy of the new DFOS optical-CT system. PMID:27019460

  5. Noninvasive CT to Iso-C3D registration for improved intraoperative visualization in computer assisted orthopedic surgery

    NASA Astrophysics Data System (ADS)

    Rudolph, Tobias; Ebert, Lars; Kowal, Jens

    2006-03-01

    Supporting surgeons in performing minimally invasive surgeries can be considered as one of the major goals of computer assisted surgery. Excellent intraoperative visualization is a prerequisite to achieve this aim. The Siremobil Iso-C 3D has become a widely used imaging device, which, in combination with a navigation system, enables the surgeon to directly navigate within the acquired 3D image volume without any extra registration steps. However, the image quality is rather low compared to a CT scan and the volume size (approx. 12 cm 3) limits its application. A regularly used alternative in computer assisted orthopedic surgery is to use of a preoperatively acquired CT scan to visualize the operating field. But, the additional registration step, necessary in order to use CT stacks for navigation is quite invasive. Therefore the objective of this work is to develop a noninvasive registration technique. In this article a solution is being proposed that registers a preoperatively acquired CT scan to the intraoperatively acquired Iso-C 3D image volume, thereby registering the CT to the tracked anatomy. The procedure aligns both image volumes by maximizing the mutual information, an algorithm that has already been applied to similar registration problems and demonstrated good results. Furthermore the accuracy of such a registration method was investigated in a clinical setup, integrating a navigated Iso-C 3D in combination with an tracking system. Initial tests based on cadaveric animal bone resulted in an accuracy ranging from 0.63mm to 1.55mm mean error.

  6. Multi-modality fusion of CT, 3D ultrasound, and tracked strain images for breast irradiation planning

    NASA Astrophysics Data System (ADS)

    Foroughi, Pezhman; Csoma, Csaba; Rivaz, Hassan; Fichtinger, Gabor; Zellars, Richard; Hager, Gregory; Boctor, Emad

    2009-02-01

    Breast irradiation significantly reduces the risk of recurrence of cancer. There is growing evidence suggesting that irradiation of only the involved area of the breast, partial breast irradiation (PBI), is as effective as whole breast irradiation. Benefits of PBI include shortened treatment time, and perhaps fewer side effects as less tissue is treated. However, these benefits cannot be realized without precise and accurate localization of the lumpectomy cavity. Several studies have shown that accurate delineation of the cavity in CT scans is very challenging and the delineated volumes differ dramatically over time and among users. In this paper, we propose utilizing 3D ultrasound (3D-US) and tracked strain images as complementary modalities to reduce uncertainties associated with current CT planning workflow. We present the early version of an integrated system that fuses 3D-US and real-time strain images. For the first time, we employ tracking information to reduce the noise in calculation of strain image by choosing the properly compressed frames and to position the strain image within the ultrasound volume. Using this system, we provide the tools to retrieve additional information from 3D-US and strain image alongside the CT scan. We have preliminarily evaluated our proposed system in a step-by-step fashion using a breast phantom and clinical experiments.

  7. 3D CT spine data segmentation and analysis of vertebrae bone lesions.

    PubMed

    Peter, R; Malinsky, M; Ourednicek, P; Jan, J

    2013-01-01

    A method is presented aiming at detecting and classifying bone lesions in 3D CT data of human spine, via Bayesian approach utilizing Markov random fields. A developed algorithm for necessary segmentation of individual possibly heavily distorted vertebrae based on 3D intensity modeling of vertebra types is presented as well. PMID:24110203

  8. In vivo 3D PIXE-micron-CT imaging of Drosophila melanogaster using a contrast agent

    NASA Astrophysics Data System (ADS)

    Matsuyama, Shigeo; Hamada, Naoki; Ishii, Keizo; Nozawa, Yuichiro; Ohkura, Satoru; Terakawa, Atsuki; Hatori, Yoshinobu; Fujiki, Kota; Fujiwara, Mitsuhiro; Toyama, Sho

    2015-04-01

    In this study, we developed a three-dimensional (3D) computed tomography (CT) in vivo imaging system for imaging small insects with micrometer resolution. The 3D CT imaging system, referred to as 3D PIXE-micron-CT (PIXEμCT), uses characteristic X-rays produced by ion microbeam bombardment of a metal target. PIXEμCT was used to observe the body organs and internal structure of a living Drosophila melanogaster. Although the organs of the thorax were clearly imaged, the digestive organs in the abdominal cavity could not be clearly discerned initially, with the exception of the rectum and the Malpighian tubule. To enhance the abdominal images, a barium sulfate powder radiocontrast agent was added. For the first time, 3D images of the ventriculus of a living D. melanogaster were obtained. Our results showed that PIXEμCT can provide in vivo 3D-CT images that reflect correctly the structure of individual living organs, which is expected to be very useful in biological research.

  9. Filtering method for 3D laser scanning point cloud

    NASA Astrophysics Data System (ADS)

    Liu, Da; Wang, Li; Hao, Yuncai; Zhang, Jun

    2015-10-01

    In recent years, with the rapid development of the hardware and software of the three-dimensional model acquisition, three-dimensional laser scanning technology is utilized in various aspects, especially in space exploration. The point cloud filter is very important before using the data. In the paper, considering both the processing quality and computing speed, an improved mean-shift point cloud filter method is proposed. Firstly, by analyze the relevance of the normal vector between the upcoming processing point and the near points, the iterative neighborhood of the mean-shift is selected dynamically, then the high frequency noise is constrained. Secondly, considering the normal vector of the processing point, the normal vector is updated. Finally, updated position is calculated for each point, then each point is moved in the normal vector according to the updated position. The experimental results show that the large features are retained, at the same time, the small sharp features are also existed for different size and shape of objects, so the target feature information is protected precisely. The computational complexity of the proposed method is not high, it can bring high precision results with fast speed, so it is very suitable for space application. It can also be utilized in civil, such as large object measurement, industrial measurement, car navigation etc. In the future, filter with the help of point strength will be further exploited.

  10. Reduced Scan Time 3D FLAIR using Modulated Inversion and Repetition Time

    PubMed Central

    Gai, Neville D.; Butman, John A.

    2014-01-01

    Purpose To design and evaluate a new reduced scan time 3D FLuid Attenuated Inversion Recovery (FLAIR) sequence. Materials and Methods The 3D FLAIR sequence was modified so that the repetition time was modulated in a predetermined smooth fashion (3D mFLAIR). Inversion times were adjusted accordingly to maintain CSF suppression. Simulations were performed to determine SNR for gray matter (GM), white matter (WM) and CSF. Fourteen volunteers were imaged using the modified and product sequence. SNR measurements were performed in GM, WM and CSF. Mean value and the 95% confidence interval ([CI]) were assessed. Scan time for the 3D FLAIR and 3D mFLAIR sequences was measured. Results There was no statistically significant difference in the SNR measured in GM (P value = 0.5; mean SNR = 42.8 [CI]: 38.2-45.5 vs 42.2 [CI]: 38.3-46.1 for 3D FLAIR and 3D mFLAIR, respectively) and WM (P value = 0.25; mean SNR = 32.1 [CI]: 30.3-33.8 vs 32.9 [CI]: 31.1-34.7). Scan time reduction greater than 30% was achieved for the given parameter set with the 3D mFLAIR sequence. Conclusion Scan time for 3D FLAIR can be effectively reduced by modulating repetition and inversion time in a predetermined fashion while maintaining the SNR and CNR of a constant TR sequence. PMID:24979311

  11. Data-fusion of high resolution X-ray CT, SEM and EDS for 3D and pseudo-3D chemical and structural characterization of sandstone.

    PubMed

    De Boever, Wesley; Derluyn, Hannelore; Van Loo, Denis; Van Hoorebeke, Luc; Cnudde, Veerle

    2015-07-01

    When dealing with the characterization of the structure and composition of natural stones, problems of representativeness and choice of analysis technique almost always occur. Since feature-sizes are typically spread over the nanometer to centimeter range, there is never one single technique that allows a rapid and complete characterization. Over the last few decades, high resolution X-ray CT (μ-CT) has become an invaluable tool for the 3D characterization of many materials, including natural stones. This technique has many important advantages, but there are also some limitations, including a tradeoff between resolution and sample size and a lack of chemical information. For geologists, this chemical information is of importance for the determination of minerals inside samples. We suggest a workflow for the complete chemical and structural characterization of a representative volume of a heterogeneous geological material. This workflow consists of combining information derived from CT scans at different spatial resolutions with information from scanning electron microscopy and energy-dispersive X-ray spectroscopy. PMID:25939085

  12. Test of 3D CT reconstructions by EM + TV algorithm from undersampled data

    SciTech Connect

    Evseev, Ivan; Ahmann, Francielle; Silva, Hamilton P. da

    2013-05-06

    Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128 Multiplication-Sign 128 Multiplication-Sign 128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

  13. Construction of realistic liver phantoms from patient images using 3D printer and its application in CT image quality assessment

    NASA Astrophysics Data System (ADS)

    Leng, Shuai; Yu, Lifeng; Vrieze, Thomas; Kuhlmann, Joel; Chen, Baiyu; McCollough, Cynthia H.

    2015-03-01

    The purpose of this study is to use 3D printing techniques to construct a realistic liver phantom with heterogeneous background and anatomic structures from patient CT images, and to use the phantom to assess image quality with filtered back-projection and iterative reconstruction algorithms. Patient CT images were segmented into liver tissues, contrast-enhanced vessels, and liver lesions using commercial software, based on which stereolithography (STL) files were created and sent to a commercial 3D printer. A 3D liver phantom was printed after assigning different printing materials to each object to simulate appropriate attenuation of each segmented object. As high opacity materials are not available for the printer, we printed hollow vessels and filled them with iodine solutions of adjusted concentration to represent enhance levels in contrast-enhanced liver scans. The printed phantom was then placed in a 35×26 cm oblong-shaped water phantom and scanned repeatedly at 4 dose levels. Images were reconstructed using standard filtered back-projection and an iterative reconstruction algorithm with 3 different strength settings. Heterogeneous liver background were observed from the CT images and the difference in CT numbers between lesions and background were representative for low contrast lesions in liver CT studies. CT numbers in vessels filled with iodine solutions represented the enhancement of liver arteries and veins. Images were run through a Channelized Hotelling model observer with Garbor channels and ROC analysis was performed. The AUC values showed performance improvement using the iterative reconstruction algorithm and the amount of improvement increased with strength setting.

  14. 3D Dose Verification Using Tomotherapy CT Detector Array

    SciTech Connect

    Sheng Ke; Jones, Ryan; Yang Wensha; Saraiya, Siddharth; Schneider, Bernard; Chen Quan; Sobering, Geoff; Olivera, Gustavo; Read, Paul

    2012-02-01

    Purpose: To evaluate a three-dimensional dose verification method based on the exit dose using the onboard detector of tomotherapy. Methods and Materials: The study included 347 treatment fractions from 24 patients, including 10 prostate, 5 head and neck (HN), and 9 spinal stereotactic body radiation therapy (SBRT) cases. Detector sonograms were retrieved and back-projected to calculate entrance fluence, which was then forward-projected on the CT images to calculate the verification dose, which was compared with ion chamber and film measurement in the QA plans and with the planning dose in patient plans. Results: Root mean square (RMS) errors of 2.0%, 2.2%, and 2.0% were observed comparing the dose verification (DV) and the ion chamber measured point dose in the phantom plans for HN, prostate, and spinal SBRT patients, respectively. When cumulative dose in the entire treatment is considered, for HN patients, the error of the mean dose to the planning target volume (PTV) varied from 1.47% to 5.62% with a RMS error of 3.55%. For prostate patients, the error of the mean dose to the prostate target volume varied from -5.11% to 3.29%, with a RMS error of 2.49%. The RMS error of maximum doses to the bladder and the rectum were 2.34% (-4.17% to 2.61%) and 2.64% (-4.54% to 3.94%), respectively. For the nine spinal SBRT patients, the RMS error of the minimum dose to the PTV was 2.43% (-5.39% to 2.48%). The RMS error of maximum dose to the spinal cord was 1.05% (-2.86% to 0.89%). Conclusions: An excellent agreement was observed between the measurement and the verification dose. In the patient treatments, the agreement in doses to the majority of PTVs and organs at risk is within 5% for the cumulative treatment course doses. The dosimetric error strongly depends on the error in multileaf collimator leaf opening time with a sensitivity correlating to the gantry rotation period.

  15. Repositioning accuracy of two different mask systems-3D revisited: Comparison using true 3D/3D matching with cone-beam CT

    SciTech Connect

    Boda-Heggemann, Judit . E-mail: judit.boda-heggemann@radonk.ma.uni-heidelberg.de; Walter, Cornelia; Rahn, Angelika; Wertz, Hansjoerg; Loeb, Iris; Lohr, Frank; Wenz, Frederik

    2006-12-01

    Purpose: The repositioning accuracy of mask-based fixation systems has been assessed with two-dimensional/two-dimensional or two-dimensional/three-dimensional (3D) matching. We analyzed the accuracy of commercially available head mask systems, using true 3D/3D matching, with X-ray volume imaging and cone-beam CT. Methods and Materials: Twenty-one patients receiving radiotherapy (intracranial/head-and-neck tumors) were evaluated (14 patients with rigid and 7 with thermoplastic masks). X-ray volume imaging was analyzed online and offline separately for the skull and neck regions. Translation/rotation errors of the target isocenter were analyzed. Four patients were treated to neck sites. For these patients, repositioning was aided by additional body tattoos. A separate analysis of the setup error on the basis of the registration of the cervical vertebra was performed. The residual error after correction and intrafractional motility were calculated. Results: The mean length of the displacement vector for rigid masks was 0.312 {+-} 0.152 cm (intracranial) and 0.586 {+-} 0.294 cm (neck). For the thermoplastic masks, the value was 0.472 {+-} 0.174 cm (intracranial) and 0.726 {+-} 0.445 cm (neck). Rigid masks with body tattoos had a displacement vector length in the neck region of 0.35 {+-} 0.197 cm. The intracranial residual error and intrafractional motility after X-ray volume imaging correction for rigid masks was 0.188 {+-} 0.074 cm, and was 0.134 {+-} 0.14 cm for thermoplastic masks. Conclusions: The results of our study have demonstrated that rigid masks have a high intracranial repositioning accuracy per se. Given the small residual error and intrafractional movement, thermoplastic masks may also be used for high-precision treatments when combined with cone-beam CT. The neck region repositioning accuracy was worse than the intracranial accuracy in both cases. However, body tattoos and image guidance improved the accuracy. Finally, the combination of both mask

  16. Application to monitoring of tailings dam based on 3D laser scanning technology

    NASA Astrophysics Data System (ADS)

    Ren, Fang; Zhang, Aiwu

    2011-06-01

    This paper presented a new method of monitoring of tailing dam based on 3D laser scanning technology and gave the method flow of acquiring and processing the tailing dam data. Taking the measured data for example, the author analyzed the dam deformation by generating the TIN, DEM and the curvature graph, and proved that it's feasible to global monitor the tailing dam using 3D laser scanning technology from the theory and method.

  17. Segmentation of vertebral bodies in CT and MR images based on 3D deterministic models

    NASA Astrophysics Data System (ADS)

    Štern, Darko; Vrtovec, Tomaž; Pernuš, Franjo; Likar, Boštjan

    2011-03-01

    The evaluation of vertebral deformations is of great importance in clinical diagnostics and therapy of pathological conditions affecting the spine. Although modern clinical practice is oriented towards the computed tomography (CT) and magnetic resonance (MR) imaging techniques, as they can provide a detailed 3D representation of vertebrae, the established methods for the evaluation of vertebral deformations still provide only a two-dimensional (2D) geometrical description. Segmentation of vertebrae in 3D may therefore not only improve their visualization, but also provide reliable and accurate 3D measurements of vertebral deformations. In this paper we propose a method for 3D segmentation of individual vertebral bodies that can be performed in CT and MR images. Initialized with a single point inside the vertebral body, the segmentation is performed by optimizing the parameters of a 3D deterministic model of the vertebral body to achieve the best match of the model to the vertebral body in the image. The performance of the proposed method was evaluated on five CT (40 vertebrae) and five T2-weighted MR (40 vertebrae) spine images, among them five are normal and five are pathological. The results show that the proposed method can be used for 3D segmentation of vertebral bodies in CT and MR images and that the proposed model can describe a variety of vertebral body shapes. The method may be therefore used for initializing whole vertebra segmentation or reliably describing vertebral body deformations.

  18. Multimodal 3D PET/CT system for bronchoscopic procedure planning

    NASA Astrophysics Data System (ADS)

    Cheirsilp, Ronnarit; Higgins, William E.

    2013-02-01

    Integrated positron emission tomography (PET) / computed-tomography (CT) scanners give 3D multimodal data sets of the chest. Such data sets offer the potential for more complete and specific identification of suspect lesions and lymph nodes for lung-cancer assessment. This in turn enables better planning of staging bronchoscopies. The richness of the data, however, makes the visualization and planning process difficult. We present an integrated multimodal 3D PET/CT system that enables efficient region identification and bronchoscopic procedure planning. The system first invokes a series of automated 3D image-processing methods that construct a 3D chest model. Next, the user interacts with a set of interactive multimodal graphical tools that facilitate procedure planning for specific regions of interest (ROIs): 1) an interactive region candidate list that enables efficient ROI viewing in all tools; 2) a virtual PET-CT bronchoscopy rendering with SUV quantitative visualization to give a "fly through" endoluminal view of prospective ROIs; 3) transverse, sagittal, coronal multi-planar reformatted (MPR) views of the raw CT, PET, and fused CT-PET data; and 4) interactive multimodal volume/surface rendering to give a 3D perspective of the anatomy and candidate ROIs. In addition the ROI selection process is driven by a semi-automatic multimodal method for region identification. In this way, the system provides both global and local information to facilitate more specific ROI identification and procedure planning. We present results to illustrate the system's function and performance.

  19. The potential role of dedicated 3D breast CT as a diagnostic tool: review and early clinical examples.

    PubMed

    O'Connell, Avice M; Karellas, Andrew; Vedantham, Srinivasan

    2014-01-01

    Mammography is the gold standard in routine screening for the detection of breast cancer in the general population. However, limitations in sensitivity, particularly in dense breasts, has motivated the development of alternative imaging techniques such as digital breast tomosynthesis, whole breast ultrasound, breast-specific gamma imaging, and more recently dedicated breast computed tomography or "breast CT". Virtually all diagnostic work-ups of asymptomatic nonpalpable findings arise from screening mammography. In most cases, diagnostic mammography and ultrasound are sufficient for diagnosis, with magnetic resonance imaging (MRI) playing an occasional role. Digital breast tomosynthesis, a limited-angle tomographic technique, is increasingly being used for screening. Dedicated breast CT has full three-dimensional (3D) capability with near-isotropic resolution, which could potentially improve diagnostic accuracy. In current dedicated breast CT clinical prototypes, 300-500 low-dose projections are acquired in a circular trajectory around the breast using a flat panel detector, followed by image reconstruction to provide the 3D breast volume. The average glandular dose to the breast from breast CT can range from as little as a two-view screening mammogram to approximately that of a diagnostic mammography examination. Breast CT displays 3D images of the internal structures of the breast; therefore, evaluation of suspicious features like microcalcifications, masses, and asymmetries can be made in multiple anatomical planes from a single scan. The potential role of breast CT for diagnostic imaging is illustrated here through clinical examples such as imaging soft tissue abnormalities and microcalcifications. The potential for breast CT to serve as an imaging tool for extent of disease evaluation and for monitoring neo-adjuvant chemotherapy response is also illustrated. PMID:25199995

  20. The effect of CT dose on glenohumeral joint congruency measurements using 3D reconstructed patient-specific bone models

    NASA Astrophysics Data System (ADS)

    Lalone, Emily A.; Fox, Anne-Marie V.; Kedgley, Angela E.; Jenkyn, Thomas R.; King, Graham J. W.; Athwal, George S.; Johnson, James A.; Peters, Terry M.

    2011-10-01

    The study of joint congruency at the glenohumeral joint of the shoulder using computed tomography (CT) and three-dimensional (3D) reconstructions of joint surfaces is an area of significant clinical interest. However, ionizing radiation delivered to patients during CT examinations is much higher than other types of radiological imaging. The shoulder represents a significant challenge for this modality as it is adjacent to the thyroid gland and breast tissue. The objective of this study was to determine the optimal CT scanning techniques that would minimize radiation dose while accurately quantifying joint congruency of the shoulder. The results suggest that only one-tenth of the standard applied total current (mA) and a pitch ratio of 1.375:1 was necessary to produce joint congruency values consistent with that of the higher dose scans. Using the CT scanning techniques examined in this study, the effective dose applied to the shoulder to quantify joint congruency was reduced by 88.9% compared to standard clinical CT imaging techniques.

  1. Visualising, segmenting and analysing heterogenous glacigenic sediments using 3D x-ray CT.

    NASA Astrophysics Data System (ADS)

    Carr, Simon; Diggens, Lucy; Groves, John; O'Sullivan, Catherine; Marsland, Rhona

    2015-04-01

    , especially with regard to using such data to improve understanding of mechanisms of particle motion and fabric development during subglacial strain. In this study, we present detailed investigation of subglacial tills from the UK, Iceland and Poland, to explore the challenges in segmenting these highly variable sediment bodies for 3D microfabric analysis. A calibration study is reported to compare various approaches to CT data segmentation to manually segmented datasets, from which an optimal workflow is developed, using a combination of the WEKA Trainable Segmentation tool within ImageJ to segment the data, followed by object-based analysis using Blob3D. We then demonstrate the value of this analysis through the analysis of true 3D microfabric data from a Last Glacial Maximum till deposit located at Morston, North Norfolk. Seven undisturbed sediment samples were scanned and analysed using high-resolution 3D X-ray computed tomography. Large (~5,000 to ~16,000) populations of individual particles are objectively and systematically segmented and identified. These large datasets are then subject to detailed interrogation using bespoke code for analysing particle fabric within Matlab, including the application of fabric-tensor analysis, by which fabrics can be weighted and scaled by key variables such as size and shape. We will present initial findings from these datasets, focusing particularly on overcoming the methodological challenges of obtaining robust datasets of sediments with highly complex, mixed compositional sediments.

  2. Remote z-scanning with a macroscopic voice coil motor for fast 3D multiphoton laser scanning microscopy

    PubMed Central

    Rupprecht, Peter; Prendergast, Andrew; Wyart, Claire; Friedrich, Rainer W

    2016-01-01

    There is a high demand for 3D multiphoton imaging in neuroscience and other fields but scanning in axial direction presents technical challenges. We developed a focusing technique based on a remote movable mirror that is conjugate to the specimen plane and translated by a voice coil motor. We constructed cost-effective z-scanning modules from off-the-shelf components that can be mounted onto standard multiphoton laser scanning microscopes to extend scan patterns from 2D to 3D. Systems were designed for large objectives and provide high resolution, high speed and a large z-scan range (>300 μm). We used these systems for 3D multiphoton calcium imaging in the adult zebrafish brain and measured odor-evoked activity patterns across >1500 neurons with single-neuron resolution and high signal-to-noise ratio. PMID:27231612

  3. Remote z-scanning with a macroscopic voice coil motor for fast 3D multiphoton laser scanning microscopy.

    PubMed

    Rupprecht, Peter; Prendergast, Andrew; Wyart, Claire; Friedrich, Rainer W

    2016-05-01

    There is a high demand for 3D multiphoton imaging in neuroscience and other fields but scanning in axial direction presents technical challenges. We developed a focusing technique based on a remote movable mirror that is conjugate to the specimen plane and translated by a voice coil motor. We constructed cost-effective z-scanning modules from off-the-shelf components that can be mounted onto standard multiphoton laser scanning microscopes to extend scan patterns from 2D to 3D. Systems were designed for large objectives and provide high resolution, high speed and a large z-scan range (>300 μm). We used these systems for 3D multiphoton calcium imaging in the adult zebrafish brain and measured odor-evoked activity patterns across >1500 neurons with single-neuron resolution and high signal-to-noise ratio. PMID:27231612

  4. Acquisition, preprocessing, and reconstruction of ultralow dose volumetric CT scout for organ-based CT scan planning

    SciTech Connect

    Yin, Zhye De Man, Bruno; Yao, Yangyang; Wu, Mingye; Montillo, Albert; Edic, Peter M.; Kalra, Mannudeep

    2015-05-15

    Purpose: Traditionally, 2D radiographic preparatory scan images (scout scans) are used to plan diagnostic CT scans. However, a 3D CT volume with a full 3D organ segmentation map could provide superior information for customized scan planning and other purposes. A practical challenge is to design the volumetric scout acquisition and processing steps to provide good image quality (at least good enough to enable 3D organ segmentation) while delivering a radiation dose similar to that of the conventional 2D scout. Methods: The authors explored various acquisition methods, scan parameters, postprocessing methods, and reconstruction methods through simulation and cadaver data studies to achieve an ultralow dose 3D scout while simultaneously reducing the noise and maintaining the edge strength around the target organ. Results: In a simulation study, the 3D scout with the proposed acquisition, preprocessing, and reconstruction strategy provided a similar level of organ segmentation capability as a traditional 240 mAs diagnostic scan, based on noise and normalized edge strength metrics. At the same time, the proposed approach delivers only 1.25% of the dose of a traditional scan. In a cadaver study, the authors’ pictorial-structures based organ localization algorithm successfully located the major abdominal-thoracic organs from the ultralow dose 3D scout obtained with the proposed strategy. Conclusions: The authors demonstrated that images with a similar degree of segmentation capability (interpretability) as conventional dose CT scans can be achieved with an ultralow dose 3D scout acquisition and suitable postprocessing. Furthermore, the authors applied these techniques to real cadaver CT scans with a CTDI dose level of less than 0.1 mGy and successfully generated a 3D organ localization map.

  5. Automatic organ localizations on 3D CT images by using majority-voting of multiple 2D detections based on local binary patterns and Haar-like features

    NASA Astrophysics Data System (ADS)

    Zhou, Xiangrong; Yamaguchi, Shoutarou; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Fujita, Hiroshi

    2013-02-01

    This paper describes an approach to accomplish the fast and automatic localization of the different inner organ regions on 3D CT scans. The proposed approach combines object detections and the majority voting technique to achieve the robust and quick organ localization. The basic idea of proposed method is to detect a number of 2D partial appearances of a 3D target region on CT images from multiple body directions, on multiple image scales, by using multiple feature spaces, and vote all the 2D detecting results back to the 3D image space to statistically decide one 3D bounding rectangle of the target organ. Ensemble learning was used to train the multiple 2D detectors based on template matching on local binary patterns and Haar-like feature spaces. A collaborative voting was used to decide the corner coordinates of the 3D bounding rectangle of the target organ region based on the coordinate histograms from detection results in three body directions. Since the architecture of the proposed method (multiple independent detections connected to a majority voting) naturally fits the parallel computing paradigm and multi-core CPU hardware, the proposed algorithm was easy to achieve a high computational efficiently for the organ localizations on a whole body CT scan by using general-purpose computers. We applied this approach to localization of 12 kinds of major organ regions independently on 1,300 torso CT scans. In our experiments, we randomly selected 300 CT scans (with human indicated organ and tissue locations) for training, and then, applied the proposed approach with the training results to localize each of the target regions on the other 1,000 CT scans for the performance testing. The experimental results showed the possibility of the proposed approach to automatically locate different kinds of organs on the whole body CT scans.

  6. Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

    NASA Astrophysics Data System (ADS)

    Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

    2016-03-01

    In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

  7. A 3-D active shape model driven by fuzzy inference: application to cardiac CT and MR.

    PubMed

    van Assen, Hans C; Danilouchkine, Mikhail G; Dirksen, Martijn S; Reiber, Johan H C; Lelieveldt, Boudewijn P F

    2008-09-01

    Manual quantitative analysis of cardiac left ventricular function using Multislice CT and MR is arduous because of the large data volume. In this paper, we present a 3-D active shape model (ASM) for semiautomatic segmentation of cardiac CT and MR volumes, without the requirement of retraining the underlying statistical shape model. A fuzzy c-means based fuzzy inference system was incorporated into the model. Thus, relative gray-level differences instead of absolute gray values were used for classification of 3-D regions of interest (ROIs), removing the necessity of training different models for different modalities/acquisition protocols. The 3-D ASM was evaluated using 25 CT and 15 MR datasets. Automatically generated contours were compared to expert contours in 100 locations. For CT, 82.4% of epicardial contours and 74.1% of endocardial contours had a maximum error of 5 mm along 95% of the contour arc length. For MR, those numbers were 93.2% (epicardium) and 91.4% (endocardium). Volume regression analysis revealed good linear correlations between manual and semiautomatic volumes, r(2) >/= 0.98. This study shows that the fuzzy inference 3-D ASM is a robust promising instrument for semiautomatic cardiac left ventricle segmentation. Without retraining its statistical shape component, it is applicable to routinely acquired CT and MR studies. PMID:18779074

  8. The potential role of dedicated 3D breast CT as a diagnostic tool: Review and early clinical examples

    PubMed Central

    O’Connell, Avice M.; Karellas, Andrew; Vedantham, Srinivasan

    2014-01-01

    Mammography is the gold standard in routine screening for the detection of breast cancer in the general population. However limitations in sensitivity, particularly in dense breasts, has motivated the development of alternative imaging techniques such as digital breast tomosynthesis, whole breast ultrasound, breast specific gamma imaging, and more recently dedicated breast computed tomography or “breast CT”. Virtually all diagnostic work-ups of asymptomatic nonpalpable findings arise from screening mammography. In most cases, diagnostic mammography and ultrasound are sufficient for diagnosis, with magnetic resonance imaging (MRI) playing an occasional role. Digital breast tomosynthesis, a limited-angle tomographic technique, is increasingly being used for screening. Dedicated breast CT has full three-dimensional (3D) capability with near-isotropic resolution, which could potentially improve diagnostic accuracy. In current dedicated breast CT clinical prototypes, 300-500 low-dose projections are acquired in a circular trajectory around the breast using a flat panel detector, followed by image reconstruction to provide the 3D breast volume. The average glandular dose to the breast from breast CT can range from as little as a two-view screening mammogram to approximately that of a diagnostic mammography examination. Breast CT displays 3D images of the internal structures of the breast; therefore, evaluation of suspicious features like microcalcifications, masses, and asymmetries can be made in multiple anatomical planes from a single scan. The potential role of breast CT for diagnostic imaging is illustrated here through clinical examples such as imaging soft tissue abnormalities and microcalcifications. The potential for breast CT to serve as an imaging tool for extent of disease evaluation and for monitoring neoadjuvant chemotherapy response is also illustrated. PMID:25199995

  9. Comparison of 3d Reconstruction Services and Terrestrial Laser Scanning for Cultural Heritage Documentation

    NASA Astrophysics Data System (ADS)

    Rasztovits, S.; Dorninger, P.

    2013-07-01

    Terrestrial Laser Scanning (TLS) is an established method to reconstruct the geometrical surface of given objects. Current systems allow for fast and efficient determination of 3D models with high accuracy and richness in detail. Alternatively, 3D reconstruction services are using images to reconstruct the surface of an object. While the instrumental expenses for laser scanning systems are high, upcoming free software services as well as open source software packages enable the generation of 3D models using digital consumer cameras. In addition, processing TLS data still requires an experienced user while recent web-services operate completely automatically. An indisputable advantage of image based 3D modeling is its implicit capability for model texturing. However, the achievable accuracy and resolution of the 3D models is lower than those of laser scanning data. Within this contribution, we investigate the results of automated web-services for image based 3D model generation with respect to a TLS reference model. For this, a copper sculpture was acquired using a laser scanner and using image series of different digital cameras. Two different webservices, namely Arc3D and AutoDesk 123D Catch were used to process the image data. The geometric accuracy was compared for the entire model and for some highly structured details. The results are presented and interpreted based on difference models. Finally, an economical comparison of the generation of the models is given considering the interactive and processing time costs.

  10. Using optically scanned 3D data in the restoration of Michelangelo's David

    NASA Astrophysics Data System (ADS)

    Scopigno, Roberto; Cignoni, Paolo; Callieri, Marco; Ganovelli, Fabio; Impoco, G.; Pingi, P.; Ponchio, F.

    2003-10-01

    Modern 3D scanning technologies allow to reconstruct 3D digital representations of Cultural Heritage artifacts in a semi-automatic way, characterized by very high accuracy and wealth of details. The availability of an accurate digital representation opens several possibilities of utilization to experts (restorers, archivists, museum curators), or to ordinary people (students, museum visitors). 3D scanned data are commonly used for the production of animations, interactive visualizations, or virtual reality applications. A much more exciting opportunity is to use these data in the restoration of Cultural Heritage artworks. The integration between 3D graphic and restoration represents an open research field where many new supporting tools are required; the David restoration project has given several starting points and guidelines to the definition and development of innovative solutions. Digital 3D models can be used in two different but not subsidiary modes: as an instrument for the execution of specific investigations and as a supporting media for the archival and integration of all the restoration-related information, gathered with the different studies and analysis performed on the artwork. In this paper we present some recent work done in the framework of the Michelangelo's David restoration project. A 3D model of the David was reconstructed by the Digital Michelangelo Project, using laser-based 3D scanning technology. We have developed some tools to make those data accessible and useful in the restoration. Preliminary results are reported here together with some directions for further research.

  11. Hyoid bone development: An assessment of optimal CT scanner parameters and 3D volume rendering techniques

    PubMed Central

    Cotter, Meghan M.; Whyms, Brian J.; Kelly, Michael P.; Doherty, Benjamin M.; Gentry, Lindell R.; Bersu, Edward T.; Vorperian, Houri K.

    2015-01-01

    The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared to corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques. PMID:25810349

  12. Intrathoracic tumour motion estimation from CT imaging using the 3D optical flow method

    NASA Astrophysics Data System (ADS)

    Guerrero, Thomas; Zhang, Geoffrey; Huang, Tzung-Chi; Lin, Kang-Ping

    2004-09-01

    The purpose of this work was to develop and validate an automated method for intrathoracic tumour motion estimation from breath-hold computed tomography (BH CT) imaging using the three-dimensional optical flow method (3D OFM). A modified 3D OFM algorithm provided 3D displacement vectors for each voxel which were used to map tumour voxels on expiration BH CT onto inspiration BH CT images. A thoracic phantom and simulated expiration/inspiration BH CT pairs were used for validation. The 3D OFM was applied to the measured inspiration and expiration BH CT images from one lung cancer and one oesophageal cancer patient. The resulting displacements were plotted in histogram format and analysed to provide insight regarding the tumour motion. The phantom tumour displacement was measured as 1.20 and 2.40 cm with full-width at tenth maximum (FWTM) for the distribution of displacement estimates of 0.008 and 0.006 cm, respectively. The maximum error of any single voxel's motion estimate was 1.1 mm along the z-dimension or approximately one-third of the z-dimension voxel size. The simulated BH CT pairs revealed an rms error of less than 0.25 mm. The displacement of the oesophageal tumours was nonuniform and up to 1.4 cm, this was a new finding. A lung tumour maximum displacement of 2.4 cm was found in the case evaluated. In conclusion, 3D OFM provided an accurate estimation of intrathoracic tumour motion, with estimated errors less than the voxel dimension in a simulated motion phantom study. Surprisingly, oesophageal tumour motion was large and nonuniform, with greatest motion occurring at the gastro-oesophageal junction. Presented at The IASTED Second International Conference on Biomedical Engineering (BioMED 2004), Innsbruck, Austria, 16-18 February 2004.

  13. 3D electron density imaging using single scattered x rays with application to breast CT and mammographic screening

    NASA Astrophysics Data System (ADS)

    van Uytven, Eric Peter

    Screening mammography is the current standard in detecting breast cancer. However, its fundamental disadvantage is that it projects a 3D object into a 2D image. Small lesions are difficult to detect when superimposed over layers of normal tissue. Commercial Computed Tomography (CT) produces a true 3D image yet has a limited role in mammography due to relatively low resolution and contrast. With the intent of enhancing mammography and breast CT, we have developed an algorithm which can produce 3D electron density images using a single projection. Imaging an object with x rays produces a characteristic scattered photon spectrum at the detector plane. A known incident beam spectrum, beam shape, and arbitrary 3D matrix of electron density values enable a theoretical scattered photon distribution to be calculated. An iterative minimization algorithm is used to make changes to the electron density voxel matrix to reduce regular differences between the theoretical and the experimentally measured distributions. The object is characterized by the converged electron density image. This technique has been validated in simulation using data produced by the EGSnrc Monte Carlo code system. At both mammographic and CT energies, a scanning polychromatic pencil beam was used to image breast tissue phantoms containing lesion-like inhomogeneities. The resulting Monte Carlo data is processed using a Nelder-Mead iterative algorithm (MATLAB) to produce the 3D matrix of electron density values. Resulting images have confirmed the ability of the algorithm to detect various 1x1x2.5 mm3 lesions with calcification content as low as 0.5% (p<0.005) at a dose comparable to mammography.

  14. Automated lung segmentation of low resolution CT scans of rats

    NASA Astrophysics Data System (ADS)

    Rizzo, Benjamin M.; Haworth, Steven T.; Clough, Anne V.

    2014-03-01

    Dual modality micro-CT and SPECT imaging can play an important role in preclinical studies designed to investigate mechanisms, progression, and therapies for acute lung injury in rats. SPECT imaging involves examining the uptake of radiopharmaceuticals within the lung, with the hypothesis that uptake is sensitive to the health or disease status of the lung tissue. Methods of quantifying lung uptake and comparison of right and left lung uptake generally begin with identifying and segmenting the lung region within the 3D reconstructed SPECT volume. However, identification of the lung boundaries and the fissure between the left and right lung is not always possible from the SPECT images directly since the radiopharmaceutical may be taken up by other surrounding tissues. Thus, our SPECT protocol begins with a fast CT scan, the lung boundaries are identified from the CT volume, and the CT region is coregistered with the SPECT volume to obtain the SPECT lung region. Segmenting rat lungs within the CT volume is particularly challenging due to the relatively low resolution of the images and the rat's unique anatomy. Thus, we have developed an automated segmentation algorithm for low resolution micro-CT scans that utilizes depth maps to detect fissures on the surface of the lung volume. The fissure's surface location is in turn used to interpolate the fissure throughout the lung volume. Results indicate that the segmentation method results in left and right lung regions consistent with rat lung anatomy.

  15. A preliminary investigation of 3D preconditioned conjugate gradient reconstruction for cone-beam CT

    NASA Astrophysics Data System (ADS)

    Fu, Lin; De Man, Bruno; Zeng, Kai; Benson, Thomas M.; Yu, Zhou; Cao, Guangzhi; Thibault, Jean-Baptiste

    2012-03-01

    Model-based iterative reconstruction (MBIR) methods based on maximum a posteriori (MAP) estimation have been recently introduced to multi-slice CT scanners. The model-based approach has shown promising image quality improvement with reduced radiation dose compared to conventional FBP methods, but the associated high computation cost limits its widespread use in clinical environments. Among the various choices of numerical algorithms to optimize the MAP cost function, simultaneous update methods such as the conjugate gradient (CG) method have a relatively high level of parallelism to take full advantage of a new generation of many-core computing hardware. With proper preconditioning techniques, fast convergence speeds of CG algorithms have been demonstrated in 3D emission and 2D transmission reconstruction. However, 3D transmission reconstruction using preconditioned conjugate gradient (PCG) has not been reported. Additional challenges in applying PCG in 3D CT reconstruction include the large size of clinical CT data, shift-variant and incomplete sampling, and complex regularization schemes to meet the diagnostic standard of image quality. In this paper, we present a ramp-filter based PCG algorithm for 3D CT MBIR. Convergence speeds of algorithms with and without using the preconditioner are compared.

  16. An enhanced method for registration of dental surfaces partially scanned by a 3D dental laser scanning.

    PubMed

    Park, Seongjin; Kang, Ho Chul; Lee, Jeongjin; Shin, Juneseuk; Shin, Yeong Gil

    2015-01-01

    In this paper, we propose the fast and accurate registration method of partially scanned dental surfaces in a 3D dental laser scanning. To overcome the multiple point correspondence problems of conventional surface registration methods, we propose the novel depth map-based registration method to register 3D surface models. First, we convert a partially scanned 3D dental surface into a 2D image by generating the 2D depth map image of the surface model by applying a 3D rigid transformation into this model. Then, the image-based registration method using 2D depth map images accurately estimates the initial transformation between two consequently acquired surface models. To further increase the computational efficiency, we decompose the 3D rigid transformation into out-of-plane (i.e. x-, y-rotation, and z-translation) and in-plane (i.e. x-, y-translation, and z-rotation) transformations. For the in-plane transformation, we accelerate the transformation process by transforming the 2D depth map image instead of transforming the 3D surface model. For the more accurate registration of 3D surface models, we enhance iterative closest point (ICP) method for the subsequent fine registration. Our initial depth map-based registration well aligns each surface model. Therefore, our subsequent ICP method can accurately register two surface models since it is highly probable that the closest point pairs are the exact corresponding point pairs. The experimental results demonstrated that our method accurately registered partially scanned dental surfaces. Regarding the computational performance, our method delivered about 1.5 times faster registration than the conventional method. Our method can be successfully applied to the accurate reconstruction of 3D dental objects for orthodontic and prosthodontic treatment. PMID:25453381

  17. A novel two-axis micromechanical scanning transducer for handheld 3D ultrasound and photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Hsien; Zou, Jun

    2016-03-01

    This paper reports the development of a new two-axis micromechanical scanning transducer for handheld 3D ultrasound imaging. It consists of a miniaturized single-element ultrasound transducer driven by a unique 2-axis liquid-immersible electromagnetic microactuator. With a mechanical scanning frequency of 19.532 Hz and an ultrasound pulse repetition rate of 5 kHz, the scanning transducer was scanned along 60 concentric paths with 256 detection points on each to simulate a physical 2D ultrasound transducer array of 60 × 256 elements. Using the scanning transducer, 3D pulse-echo ultrasound imaging of two silicon discs immersed in water as the imaging target was successfully conducted. The lateral resolution of the 3D ultrasound image was further improved with the synthetic aperture focusing technique (SAFT). The new two-axis micromechanical scanning transducer doesn't require complex and expensive multi-channel data acquisition (DAQ) electronics. Therefore, it could provide a new approach to achieve compact and low-cost 3D ultrasound and photoacoustic imaging systems, especially for handheld operations.

  18. Application of 3D X-ray CT data sets to finite element analysis

    SciTech Connect

    Bossart, P.L.; Martz, H.E.; Brand, H.R.; Hollerbach, K.

    1995-08-31

    Finite Element Modeling (FEM) is becoming more important as industry drives toward concurrent engineering. A fundamental hindrance to fully exploiting the power of FEM is the human effort required to acquire complex part geometry, particularly as-built geometry, as a FEM mesh. Many Quantitative Non Destructive Evaluation (QNDE) techniques that produce three-dimensional (3D) data sets provide a substantial reduction in the effort required to apply FEM to as-built parts. This paper describes progress at LLNL on the application of 3D X-ray computed tomography (CT) data sets to more rapidly produce high-quality FEM meshes of complex, as-built geometries. Issues related to the volume segmentation of the 3D CT data as well as the use of this segmented data to tailor generic hexahedral FEM meshes to part specific geometries are discussed. The application of these techniques to FEM analysis in the medical field is reported here.

  19. Angle extended linear MEMS scanning system for 3D laser vision sensor

    NASA Astrophysics Data System (ADS)

    Pang, Yajun; Zhang, Yinxin; Yang, Huaidong; Zhu, Pan; Gai, Ye; Zhao, Jian; Huang, Zhanhua

    2016-09-01

    Scanning system is often considered as the most important part for 3D laser vision sensor. In this paper, we propose a method for the optical system design of angle extended linear MEMS scanning system, which has features of huge scanning degree, small beam divergence angle and small spot size for 3D laser vision sensor. The principle of design and theoretical formulas are derived strictly. With the help of software ZEMAX, a linear scanning optical system based on MEMS has been designed. Results show that the designed system can extend scanning angle from ±8° to ±26.5° with a divergence angle small than 3.5 mr, and the spot size is reduced for 4.545 times.

  20. [3D Super-resolution Reconstruction and Visualization of Pulmonary Nodules from CT Image].

    PubMed

    Wang, Bing; Fan, Xing; Yang, Ying; Tian, Xuedong; Gu, Lixu

    2015-08-01

    The aim of this study was to propose an algorithm for three-dimensional projection onto convex sets (3D POCS) to achieve super resolution reconstruction of 3D lung computer tomography (CT) images, and to introduce multi-resolution mixed display mode to make 3D visualization of pulmonary nodules. Firstly, we built the low resolution 3D images which have spatial displacement in sub pixel level between each other and generate the reference image. Then, we mapped the low resolution images into the high resolution reference image using 3D motion estimation and revised the reference image based on the consistency constraint convex sets to reconstruct the 3D high resolution images iteratively. Finally, we displayed the different resolution images simultaneously. We then estimated the performance of provided method on 5 image sets and compared them with those of 3 interpolation reconstruction methods. The experiments showed that the performance of 3D POCS algorithm was better than that of 3 interpolation reconstruction methods in two aspects, i.e., subjective and objective aspects, and mixed display mode is suitable to the 3D visualization of high resolution of pulmonary nodules. PMID:26710449

  1. Precise 3D dimensional metrology using high-resolution x-ray computed tomography (μCT)

    NASA Astrophysics Data System (ADS)

    Brunke, Oliver; Santillan, Javier; Suppes, Alexander

    2010-09-01

    Over the past decade computed tomography (CT) with conventional x-ray sources has evolved from an imaging method in medicine to a well established technology for industrial applications in fields such as material science, light metals and plastics processing, microelectronics and geology. By using modern microfocus and nanofocus X-ray tubes, parts can be scanned with sub-micrometer resolutions. Currently, micro-CT is a technology increasingly used for metrology applications in the automotive industry. CT offers big advantages compared with conventional tactile or optical coordinate measuring machines (CMMs). This is of greater importance if complex parts with hidden or difficult accessible surfaces have to be measured. In these cases, CT offers the advantage of a high density of measurement points and a non-destructive and fast capturing of the sample's complete geometry. When using this growing technology the question arises how precise a μCT based CMM can measure as compared to conventional and established methods for coordinate measurements. For characterizing the metrological capabilities of a tactile or optical CMM, internationally standardized parameters like length measurement error and probing error are defined and used. To increase the acceptance of CT as a metrological method, our work seeks to clarify the definition and usage of parameters used in the field of metrology as these apply to CT. In this paper, an overview of the process chain in CT based metrology will be given and metrological characteristics will be described. For the potential user of CT as 3D metrology tool it is important to show the measurement accuracy and repeatability on realistic samples. Following a discussion of CT metrology techniques, two samples are discussed. The first compares a measured CT Data set to CAD data using CMM data as a standard for comparison of results. The second data second realistic data set will compare the results of applying both the CMM method of

  2. 2D-3D Registration of CT Vertebra Volume to Fluoroscopy Projection: A Calibration Model Assessment

    NASA Astrophysics Data System (ADS)

    Bifulco, P.; Cesarelli, M.; Allen, R.; Romano, M.; Fratini, A.; Pasquariello, G.

    2009-12-01

    This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume) and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1 mm for displacements parallel to the fluoroscopic plane, and of order of 10 mm for the orthogonal displacement.

  3. Taking Advantage of Selective Change Driven Processing for 3D Scanning

    PubMed Central

    Vegara, Francisco; Zuccarello, Pedro; Boluda, Jose A.; Pardo, Fernando

    2013-01-01

    This article deals with the application of the principles of SCD (Selective Change Driven) vision to 3D laser scanning. Two experimental sets have been implemented: one with a classical CMOS (Complementary Metal-Oxide Semiconductor) sensor, and the other one with a recently developed CMOS SCD sensor for comparative purposes, both using the technique known as Active Triangulation. An SCD sensor only delivers the pixels that have changed most, ordered by the magnitude of their change since their last readout. The 3D scanning method is based on the systematic search through the entire image to detect pixels that exceed a certain threshold, showing the SCD approach to be ideal for this application. Several experiments for both capturing strategies have been performed to try to find the limitations in high speed acquisition/processing. The classical approach is limited by the sequential array acquisition, as predicted by the Nyquist–Shannon sampling theorem, and this has been experimentally demonstrated in the case of a rotating helix. These limitations are overcome by the SCD 3D scanning prototype achieving a significantly higher performance. The aim of this article is to compare both capturing strategies in terms of performance in the time and frequency domains, so they share all the static characteristics including resolution, 3D scanning method, etc., thus yielding the same 3D reconstruction in static scenes. PMID:24084110

  4. CT Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... 繁體中文) French (français) Hindi (हिन्दी) Japanese (日本語) Korean (한국어) Russian (Русский) Somali (af Soomaali) Spanish (español) ... スキャン - 日本語 (Japanese) Bilingual PDF Health Information Translations Korean (한국어) CT (Computerized Tomography) Scan CT 스캔 (전산화 ...

  5. Parametric modelling and segmentation of vertebral bodies in 3D CT and MR spine images

    NASA Astrophysics Data System (ADS)

    Štern, Darko; Likar, Boštjan; Pernuš, Franjo; Vrtovec, Tomaž

    2011-12-01

    Accurate and objective evaluation of vertebral deformations is of significant importance in clinical diagnostics and therapy of pathological conditions affecting the spine. Although modern clinical practice is focused on three-dimensional (3D) computed tomography (CT) and magnetic resonance (MR) imaging techniques, the established methods for evaluation of vertebral deformations are limited to measuring deformations in two-dimensional (2D) x-ray images. In this paper, we propose a method for quantitative description of vertebral body deformations by efficient modelling and segmentation of vertebral bodies in 3D. The deformations are evaluated from the parameters of a 3D superquadric model, which is initialized as an elliptical cylinder and then gradually deformed by introducing transformations that yield a more detailed representation of the vertebral body shape. After modelling the vertebral body shape with 25 clinically meaningful parameters and the vertebral body pose with six rigid body parameters, the 3D model is aligned to the observed vertebral body in the 3D image. The performance of the method was evaluated on 75 vertebrae from CT and 75 vertebrae from T2-weighted MR spine images, extracted from the thoracolumbar part of normal and pathological spines. The results show that the proposed method can be used for 3D segmentation of vertebral bodies in CT and MR images, as the proposed 3D model is able to describe both normal and pathological vertebral body deformations. The method may therefore be used for initialization of whole vertebra segmentation or for quantitative measurement of vertebral body deformations.

  6. A prototype fan-beam optical CT scanner for 3D dosimetry

    SciTech Connect

    Campbell, Warren G.; Rudko, D. A.; Braam, Nicolas A.; Jirasek, Andrew; Wells, Derek M.

    2013-06-15

    flask registration technique was shown to achieve submillimetre and subdegree placement accuracy. Dosimetry protocol investigations emphasize the need to allow gel dosimeters to cool gradually and to be scanned while at room temperature. Preliminary tests show that considerable noise reduction can be achieved with sinogram filtering and by binning image pixels into more clinically relevant grid sizes. Conclusions: This paper describes a new optical CT scanner for 3D radiation dosimetry. Tests demonstrate that it is capable of imaging both absorption-based and scatter-based samples of high opacities. Imaging protocol and gel dosimeter manufacture techniques have been adapted to produce optimal reconstruction results. These optimal results will require suitable filtering and binning techniques for noise reduction purposes.

  7. The fast and accurate 3D-face scanning technology based on laser triangle sensors

    NASA Astrophysics Data System (ADS)

    Wang, Jinjiang; Chang, Tianyu; Ge, Baozhen; Tian, Qingguo; Chen, Yang; Kong, Bin

    2013-08-01

    A laser triangle scanning method and the structure of 3D-face measurement system were introduced. In presented system, a liner laser source was selected as an optical indicated signal in order to scanning a line one times. The CCD image sensor was used to capture image of the laser line modulated by human face. The system parameters were obtained by system calibrated calculated. The lens parameters of image part of were calibrated with machine visual image method and the triangle structure parameters were calibrated with fine wire paralleled arranged. The CCD image part and line laser indicator were set with a linear motor carry which can achieve the line laser scanning form top of the head to neck. For the nose is ledge part and the eyes are sunk part, one CCD image sensor can not obtain the completed image of laser line. In this system, two CCD image sensors were set symmetric at two sides of the laser indicator. In fact, this structure includes two laser triangle measure units. Another novel design is there laser indicators were arranged in order to reduce the scanning time for it is difficult for human to keep static for longer time. The 3D data were calculated after scanning. And further data processing include 3D coordinate refine, mesh calculate and surface show. Experiments show that this system has simply structure, high scanning speed and accurate. The scanning range covers the whole head of adult, the typical resolution is 0.5mm.

  8. Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

    SciTech Connect

    Ravindran, V. R.; Sreelakshmi, C.; Vibin

    2008-09-26

    The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

  9. 3-D reconstruction of neurons from multichannel confocal laser scanning image series.

    PubMed

    Wouterlood, Floris G

    2014-01-01

    A confocal laser scanning microscope (CLSM) collects information from a thin, focal plane and ignores out-of-focus information. Scanning of a specimen, with stepwise axial (Z-) movement of the stage in between each scan, produces Z-series of confocal images of a tissue volume, which then can be used to 3-D reconstruct structures of interest. The operator first configures separate channels (e.g., laser, filters, and detector settings) for each applied fluorochrome and then acquires Z-series of confocal images: one series per channel. Channel signal separation is extremely important. Measures to avoid bleaching are vital. Post-acquisition deconvolution of the image series is often performed to increase resolution before 3-D reconstruction takes place. In the 3-D reconstruction programs described in this unit, reconstructions can be inspected in real time from any viewing angle. By altering viewing angles and by switching channels off and on, the spatial relationships of 3-D-reconstructed structures with respect to structures visualized in other channels can be studied. Since each brand of CLSM, computer program, and 3-D reconstruction package has its own proprietary set of procedures, a general approach is provided in this protocol wherever possible. PMID:24723320

  10. Vessel segmentation in 3D spectral OCT scans of the retina

    NASA Astrophysics Data System (ADS)

    Niemeijer, Meindert; Garvin, Mona K.; van Ginneken, Bram; Sonka, Milan; Abràmoff, Michael D.

    2008-03-01

    The latest generation of spectral optical coherence tomography (OCT) scanners is able to image 3D cross-sectional volumes of the retina at a high resolution and high speed. These scans offer a detailed view of the structure of the retina. Automated segmentation of the vessels in these volumes may lead to more objective diagnosis of retinal vascular disease including hypertensive retinopathy, retinopathy of prematurity. Additionally, vessel segmentation can allow color fundus images to be registered to these 3D volumes, possibly leading to a better understanding of the structure and localization of retinal structures and lesions. In this paper we present a method for automatically segmenting the vessels in a 3D OCT volume. First, the retina is automatically segmented into multiple layers, using simultaneous segmentation of their boundary surfaces in 3D. Next, a 2D projection of the vessels is produced by only using information from certain segmented layers. Finally, a supervised, pixel classification based vessel segmentation approach is applied to the projection image. We compared the influence of two methods for the projection on the performance of the vessel segmentation on 10 optic nerve head centered 3D OCT scans. The method was trained on 5 independent scans. Using ROC analysis, our proposed vessel segmentation system obtains an area under the curve of 0.970 when compared with the segmentation of a human observer.

  11. 3D Laser Scanning Modeling and Application on Dazu Thousand-hand Bodhisattva in China

    NASA Astrophysics Data System (ADS)

    Hou, M.; Zhang, X.; Wu, Y.; Hu, Y.

    2014-04-01

    The Dazu Thousand-hand Bodhisattva Statue is located at Baoding Mountain in Chongqing. It has the reputation as "the Gem of World's Rock Carving Art". At present,the Dazu Thousand-hand Bodhisattva Statue is basically well conserved, while the local damage is already very serious. However, the Dazu Thousand-hand Bodhisattva Statue is a three-dimensional caved statue, the present plane surveying and mapping device cannot reflect the preservation situation completely. Therefore, the documentation of the Dazu Thousand-hand Bodhisattva Statue using terrestrial laser scanning is of great significance. This paper will introduce a new method for superfine 3D modeling of Thousand-hand Bodhisattva based on the high-resolution 3D cloud points. By analyzing these 3D cloud points and 3D models, some useful information, such as several 3D statistics, 3D thematic map and 3D shape restoration suggestion of Thousand-hand Bodhisattva will be revealed, which are beneficial to restoration work and some other application.

  12. Automatic classification of 3D segmented CT data using data fusion and support vector machine

    NASA Astrophysics Data System (ADS)

    Osman, Ahmad; Kaftandjian, Valérie; Hassler, Ulf

    2011-07-01

    The three dimensional X-ray computed tomography (3D-CT) has proved its successful usage as inspection method in non destructive testing. The generated 3D volume using high efficiency reconstruction algorithms contains all the inner structures of the inspected part. Segmentation of this volume reveals suspicious regions which need to be classified into defects or false alarms. This paper deals with the classification step using data fusion theory and support vector machine. Results achieved are very promising and prove the effectiveness of the data fusion theory as a method to build stronger classifier.

  13. CT Scans - Multiple Languages: MedlinePlus

    MedlinePlus

    ... List of All Topics All CT Scans - Multiple Languages To use the sharing features on this page, please enable JavaScript. Arabic (العربية) Chinese - Simplified (简体中文) Chinese - Traditional (繁體中文) French ( ...

  14. Multi-detector row CT scanning in Paleoanthropology at various tube current settings and scanning mode.

    PubMed

    Badawi-Fayad, J; Yazbeck, C; Balzeau, A; Nguyen, T H; Istoc, A; Grimaud-Hervé, D; Cabanis, E- A

    2005-12-01

    The purpose of this study was to determine the optimal tube current setting and scanning mode for hominid fossil skull scanning, using multi-detector row computed tomography (CT). Four fossil skulls (La Ferrassie 1, Abri Pataud 1, CroMagnon 2 and Cro-Magnon 3) were examined by using the CT scanner LightSpeed 16 (General Electric Medical Systems) with varying dose per section (160, 250, and 300 mAs) and scanning mode (helical and conventional). Image quality of two-dimensional (2D) multiplanar reconstructions, three-dimensional (3D) reconstructions and native images was assessed by four reviewers using a four-point grading scale. An ANOVA (analysis of variance) model was used to compare the mean score for each sequence and the overall mean score according to the levels of the scanning parameters. Compared with helical CT (mean score=12.03), the conventional technique showed sustained poor image quality (mean score=4.17). With the helical mode, we observed a better image quality at 300 mAs than at 160 in the 3D sequences (P=0.03). Whereas in native images, a reduction in the effective tube current induced no degradation in image quality (P=0.05). Our study suggests a standardized protocol for fossil scanning with a 16 x 0.625 detector configuration, a 10 mm beam collimation, a 0.562:1 acquisition mode, a 0.625/0.4 mm slice thickness/reconstruction interval, a pitch of 5.62, 120 kV and 300 mAs especially when a 3D study is required. PMID:16211320

  15. Interactive annotation of textures in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Kockelkorn, Thessa T. J. P.; de Jong, Pim A.; Gietema, Hester A.; Grutters, Jan C.; Prokop, Mathias; van Ginneken, Bram

    2010-03-01

    This study describes a system for interactive annotation of thoracic CT scans. Lung volumes in these scans are segmented and subdivided into roughly spherical volumes of interest (VOIs) with homogeneous texture using a clustering procedure. For each 3D VOI, 72 features are calculated. The observer inspects the scan to determine which textures are present and annotates, with mouse clicks, several VOIs of each texture. Based on these annotations, a k-nearest-neighbor classifier is trained, which classifies all remaining VOIs in the scan. The algorithm then presents a slice with suggested annotations to the user, in which the user can correct mistakes. The classifier is retrained, taking into account these new annotations, and the user is presented another slice for correction. This process continues until at least 50% of all lung voxels in the scan have been classified. The remaining VOIs are classified automatically. In this way, the entire lung volume is annotated. The system has been applied to scans of patients with usual and non-specific interstitial pneumonia. The results of interactive annotation are compared to a setup in which the user annotates all predefined VOIs manually. The interactive system is 3.7 times as fast as complete manual annotation of VOIs and differences between the methods are similar to interobserver variability. This is a first step towards precise volumetric quantitation of texture patterns in thoracic CT in clinical research and in clinical practice.

  16. Cascaded systems analysis of the 3D NEQ for cone-beam CT and tomosynthesis

    NASA Astrophysics Data System (ADS)

    Tward, D. J.; Siewerdsen, J. H.; Fahrig, R. A.; Pineda, A. R.

    2008-03-01

    Crucial to understanding the factors that govern imaging performance is a rigorous analysis of signal and noise transfer characteristics (e.g., MTF, NPS, and NEQ) applied to a task-based performance metric (e.g., detectability index). This paper advances a theoretical framework for calculation of the NPS, NEQ, and DQE of cone-beam CT (CBCT) and tomosynthesis based on cascaded systems analysis. The model considers the 2D projection NPS propagated through a series of reconstruction stages to yield the 3D NPS, revealing a continuum (from 2D projection radiography to limited-angle tomosynthesis and fully 3D CBCT) for which NEQ and detectability index may be investigated as a function of any system parameter. Factors considered in the cascade include: system geometry; angular extent of source-detector orbit; finite number of views; log-scaling; application of ramp, apodization, and interpolation filters; back-projection; and 3D noise aliasing - all of which have a direct impact on the 3D NEQ and DQE. Calculations of the 3D NPS were found to agree with experimental measurements across a broad range of imaging conditions. The model presents a theoretical framework that unifies 3D Fourier-based performance metrology in tomosynthesis and CBCT, providing a guide to optimization that rigorously considers the system configuration, reconstruction parameters, and imaging task.

  17. Volumetric CT-based segmentation of NSCLC using 3D-Slicer

    PubMed Central

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H.; van Baardwijk, Angela; Fennessy, Fiona M.; Lewis, John H.; De Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J. W. L.

    2013-01-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the “gold standard”. The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81–0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck. PMID:24346241

  18. Volumetric CT-based segmentation of NSCLC using 3D-Slicer.

    PubMed

    Velazquez, Emmanuel Rios; Parmar, Chintan; Jermoumi, Mohammed; Mak, Raymond H; van Baardwijk, Angela; Fennessy, Fiona M; Lewis, John H; De Ruysscher, Dirk; Kikinis, Ron; Lambin, Philippe; Aerts, Hugo J W L

    2013-01-01

    Accurate volumetric assessment in non-small cell lung cancer (NSCLC) is critical for adequately informing treatments. In this study we assessed the clinical relevance of a semiautomatic computed tomography (CT)-based segmentation method using the competitive region-growing based algorithm, implemented in the free and public available 3D-Slicer software platform. We compared the 3D-Slicer segmented volumes by three independent observers, who segmented the primary tumour of 20 NSCLC patients twice, to manual slice-by-slice delineations of five physicians. Furthermore, we compared all tumour contours to the macroscopic diameter of the tumour in pathology, considered as the "gold standard". The 3D-Slicer segmented volumes demonstrated high agreement (overlap fractions > 0.90), lower volume variability (p = 0.0003) and smaller uncertainty areas (p = 0.0002), compared to manual slice-by-slice delineations. Furthermore, 3D-Slicer segmentations showed a strong correlation to pathology (r = 0.89, 95%CI, 0.81-0.94). Our results show that semiautomatic 3D-Slicer segmentations can be used for accurate contouring and are more stable than manual delineations. Therefore, 3D-Slicer can be employed as a starting point for treatment decisions or for high-throughput data mining research, such as Radiomics, where manual delineating often represent a time-consuming bottleneck. PMID:24346241

  19. Error analysis of 3D laser scanning system for gangue monitoring

    NASA Astrophysics Data System (ADS)

    Hu, Shaoxing; Xia, Yuyang; Zhang, Aiwu

    2012-01-01

    The paper put forward the system error evaluation method of 3D scanning system for gangue monitoring; analyzed system errors including integrated error which can be avoided, and measurement error which needed whole analysis; firstly established the system equation after understanding the relationship of each structure. Then, used error independent effect and spread law to set up the entire error analysis system, and simulated the trend of error changing along X, Y, Z directions. At last, it is analytic that the laser rangefinder carries some weight in system error, and the horizontal and vertical scanning angles have some influences on system error in the certain vertical and horizontal scanning parameters.

  20. Development of scanning laser sensor for underwater 3D imaging with the coaxial optics

    NASA Astrophysics Data System (ADS)

    Ochimizu, Hideaki; Imaki, Masaharu; Kameyama, Shumpei; Saito, Takashi; Ishibashi, Shoujirou; Yoshida, Hiroshi

    2014-06-01

    We have developed the scanning laser sensor for underwater 3-D imaging which has the wide scanning angle of 120º (Horizontal) x 30º (Vertical) with the compact size of 25 cm diameter and 60 cm long. Our system has a dome lens and a coaxial optics to realize both the wide scanning angle and the compactness. The system also has the feature in the sensitivity time control (STC) circuit, in which the receiving gain is increased according to the time of flight. The STC circuit contributes to detect a small signal by suppressing the unwanted signals backscattered by marine snows. We demonstrated the system performance in the pool, and confirmed the 3-D imaging with the distance of 20 m. Furthermore, the system was mounted on the autonomous underwater vehicle (AUV), and demonstrated the seafloor mapping at the depth of 100 m in the ocean.

  1. Respiratory gating for proton beam scanning versus photon 3D-CRT for breast cancer radiotherapy.

    PubMed

    Flejmer, Anna M; Edvardsson, Anneli; Dohlmar, Frida; Josefsson, Dan; Nilsson, Mats; Witt Nyström, Petra; Dasu, Alexandru

    2016-05-01

    Background Respiratory gating and proton therapy have both been proposed to reduce the cardiopulmonary burden in breast cancer radiotherapy. This study aims to investigate the additional benefit of proton radiotherapy for breast cancer with and without respiratory gating. Material and methods Twenty left-sided patients were planned on computed tomography (CT)-datasets acquired during enhanced inspiration gating (EIG) and free-breathing (FB), using photon three-dimensional conformal radiation therapy (3D-CRT) and scanned proton beams. Ten patients received treatment to the whole breast only (WBO) and 10 were treated to the breast and the regional lymph nodes (BRN). Dosimetric parameters characterizing the coverage of target volumes and the cardiopulmonary burden were compared using a paired, two-tailed Student's t-test. Results Protons ensured comparable or better target coverage than photons in all patients during both EIG and FB. The heterogeneity index decreased from 12% with photons to about 5% with protons. The mean dose to the ipsilateral lung was reduced in BRN patients from 12 Gy to 7 Gy  (RBE) in EIG and from 14 Gy to 6-7 Gy (RBE) in FB, while for WBO patients all values were about 5-6 Gy (RBE). The mean dose to heart decreased by a factor of four in WBO patients [from 1.1 Gy to 0.3 Gy (RBE) in EIG and from 2.1 Gy to 0.5 Gy (RBE) in FB] and 10 in BRN patients [from 2.1 Gy to 0.2 Gy (RBE) in EIG and from 3.4 Gy to 0.3 Gy (RBE) in FB]. Similarly, the mean and the near maximum dose to the left anterior descending artery (LAD) were significantly lower (p < 0.05) with protons in comparison with photons. Conclusion Proton spot scanning has a high potential to reduce the irradiation of organs at risk and other normal tissues for most patients, beyond what could be achieved with EIG and photon therapy. The largest dose sparing has been seen for BRN patients, both in terms of cardiopulmonary burden and integral dose. PMID:27027913

  2. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems

    PubMed Central

    Jung, Jaehoon; Kim, Jeonghyun; Yoon, Sanghyun; Kim, Sangmin; Cho, Hyoungsig; Kim, Changjae; Heo, Joon

    2015-01-01

    The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system’s trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach. PMID:25946627

  3. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems.

    PubMed

    Jung, Jaehoon; Kim, Jeonghyun; Yoon, Sanghyun; Kim, Sangmin; Cho, Hyoungsig; Kim, Changjae; Heo, Joon

    2015-01-01

    The Simultaneous Localization and Mapping (SLAM) technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs): one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system's trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach. PMID:25946627

  4. A novel high accuracy 3D scanning device for rock-art sites

    NASA Astrophysics Data System (ADS)

    Höll, T.; Holler, G.; Pinz, A.

    2014-06-01

    We are currently developing a novel 3D scanning device for rock-art. Within the European project 3D-Pitoti, this scanner shall be used to acquire 3D structure and radiometric surface properties of ancient rock-art sites in Valcamonica. Overall design goals include high spatial accuracy and precision, as well as radiometric quality beyond phototexture. This paper is devoted to the geometric measurement principle of the new scanner. We present a novel scanning scheme based on various constraints to Structure from Motion, that guarantees high accuracy of the resulting scans by combining tachymeter-based tracking of the scanner, stereo, and structure-from-motion. This method provides scale information (by calibrated stereo), and does not require ground control points, because outside-in tracking avoids the typical issues of drift in structure-from-motion. The system is designed for flexibility, high throughput, approx. 0.1 mm precision, and an overall accuracy of the reconstructed 3D structure that conforms with the specifications of the tachymeter.

  5. Mapping gray-scale image to 3D surface scanning data by ray tracing

    NASA Astrophysics Data System (ADS)

    Li, Peng; Jones, Peter R. M.

    1997-03-01

    The extraction and location of feature points from range imaging is an important but difficult task in machine vision based measurement systems. There exist some feature points which are not able to be detected from pure geometric characteristics, particularly in those measurement tasks related to the human body. The Loughborough Anthropometric Shadow Scanner (LASS) is a whole body surface scanner based on structured light technique. Certain applications of LASS require accurate location of anthropometric landmarks from the scanned data. This is sometimes impossible from existing raw data because some landmarks do not appear in the scanned data. Identification of these landmarks has to resort to surface texture of the scanned object. Modifications to LASS were made to allow gray-scale images to be captured before or after the object was scanned. Two-dimensional gray-scale image must be mapped to the scanned data to acquire the 3D coordinates of a landmark. The method to map 2D images to the scanned data is based on the colinearity conditions and ray-tracing method. If the camera center and image coordinates are known, the corresponding object point must lie on a ray starting from the camera center and connecting to the image coordinate. By intersecting the ray with the scanned surface of the object, the 3D coordinates of a point can be solved. Experimentation has demonstrated the feasibility of the method.

  6. Digimouse: a 3D whole body mouse atlas from CT and cryosection data

    PubMed Central

    Dogdas, Belma; Stout, David; Chatziioannou, Arion F; Leahy, Richard M

    2010-01-01

    We have constructed a three-dimensional (3D) whole body mouse atlas from coregistered x-ray CT and cryosection data of a normal nude male mouse. High quality PET, x-ray CT and cryosection images were acquired post mortem from a single mouse placed in a stereotactic frame with fiducial markers visible in all three modalities. The image data were coregistered to a common coordinate system using the fiducials and resampled to an isotropic 0.1 mm voxel size. Using interactive editing tools we segmented and labelled whole brain, cerebrum, cerebellum, olfactory bulbs, striatum, medulla, masseter muscles, eyes, lachrymal glands, heart, lungs, liver, stomach, spleen, pancreas, adrenal glands, kidneys, testes, bladder, skeleton and skin surface. The final atlas consists of the 3D volume, in which the voxels are labelled to define the anatomical structures listed above, with coregistered PET, x-ray CT and cryosection images. To illustrate use of the atlas we include simulations of 3D bioluminescence and PET image reconstruction. Optical scatter and absorption values are assigned to each organ to simulate realistic photon transport within the animal for bioluminescence imaging. Similarly, 511 keV photon attenuation values are assigned to each structure in the atlas to simulate realistic photon attenuation in PET. The Digimouse atlas and data are available at http://neuroimage.usc.edu/Digimouse.html. PMID:17228106

  7. Digimouse: a 3D whole body mouse atlas from CT and cryosection data

    NASA Astrophysics Data System (ADS)

    Dogdas, Belma; Stout, David; Chatziioannou, Arion F.; Leahy, Richard M.

    2007-02-01

    We have constructed a three-dimensional (3D) whole body mouse atlas from coregistered x-ray CT and cryosection data of a normal nude male mouse. High quality PET, x-ray CT and cryosection images were acquired post mortem from a single mouse placed in a stereotactic frame with fiducial markers visible in all three modalities. The image data were coregistered to a common coordinate system using the fiducials and resampled to an isotropic 0.1 mm voxel size. Using interactive editing tools we segmented and labelled whole brain, cerebrum, cerebellum, olfactory bulbs, striatum, medulla, masseter muscles, eyes, lachrymal glands, heart, lungs, liver, stomach, spleen, pancreas, adrenal glands, kidneys, testes, bladder, skeleton and skin surface. The final atlas consists of the 3D volume, in which the voxels are labelled to define the anatomical structures listed above, with coregistered PET, x-ray CT and cryosection images. To illustrate use of the atlas we include simulations of 3D bioluminescence and PET image reconstruction. Optical scatter and absorption values are assigned to each organ to simulate realistic photon transport within the animal for bioluminescence imaging. Similarly, 511 keV photon attenuation values are assigned to each structure in the atlas to simulate realistic photon attenuation in PET. The Digimouse atlas and data are available at http://neuroimage.usc.edu/Digimouse.html.

  8. Scanning Cloud Radar Observations at Azores: Preliminary 3D Cloud Products

    SciTech Connect

    Kollias, P.; Johnson, K.; Jo, I.; Tatarevic, A.; Giangrande, S.; Widener, K.; Bharadwaj, N.; Mead, J.

    2010-03-15

    The deployment of the Scanning W-Band ARM Cloud Radar (SWACR) during the AMF campaign at Azores signals the first deployment of an ARM Facility-owned scanning cloud radar and offers a prelude for the type of 3D cloud observations that ARM will have the capability to provide at all the ARM Climate Research Facility sites by the end of 2010. The primary objective of the deployment of Scanning ARM Cloud Radars (SACRs) at the ARM Facility sites is to map continuously (operationally) the 3D structure of clouds and shallow precipitation and to provide 3D microphysical and dynamical retrievals for cloud life cycle and cloud-scale process studies. This is a challenging task, never attempted before, and requires significant research and development efforts in order to understand the radar's capabilities and limitations. At the same time, we need to look beyond the radar meteorology aspects of the challenge and ensure that the hardware and software capabilities of the new systems are utilized for the development of 3D data products that address the scientific needs of the new Atmospheric System Research (ASR) program. The SWACR observations at Azores provide a first look at such observations and the challenges associated with their analysis and interpretation. The set of scan strategies applied during the SWACR deployment and their merit is discussed. The scan strategies were adjusted for the detection of marine stratocumulus and shallow cumulus that were frequently observed at the Azores deployment. Quality control procedures for the radar reflectivity and Doppler products are presented. Finally, preliminary 3D-Active Remote Sensing of Cloud Locations (3D-ARSCL) products on a regular grid will be presented, and the challenges associated with their development discussed. In addition to data from the Azores deployment, limited data from the follow-up deployment of the SWACR at the ARM SGP site will be presented. This effort provides a blueprint for the effort required for the

  9. Laser microbeam CT scanning of dosimetry gels

    NASA Astrophysics Data System (ADS)

    Maryanski, Marek J.; Ranade, Manisha K.

    2001-06-01

    A novel design of an optical tomographic scanner is described that can be used for 3D mapping of optical attenuation coefficient within translucent cylindrical objects with spatial resolution on the order of 100 microns. Our scanner design utilizes the cylindrical geometry of the imaged object to obtain the desired paths of the scanning light rays. A rotating mirror and a photodetector are placed at two opposite foci of the translucent cylinder that acts as a cylindrical lens. A He-Ne laser beam passes first through a focusing lens and then is reflected by the rotating mirror, so as to scan the interior of the cylinder with focused and parallel paraxial rays that are subsequently collected by the photodetector to produce the projection data, as the cylinder rotates in small angle increments between projections. Filtered backprojection is then used to reconstruct planar distributions of optical attenuation coefficient in the cylinder. Multiplanar scans are used to obtain a complete 3D tomographic reconstruction. Among other applications, the scanner can be used in radiation therapy dosimetry and quality assurance for mapping 3D radiation dose distributions in various types of tissue-equivalent gel phantoms that change their optical attenuation coefficients in proportion to the absorbed radiation dose.

  10. Effect of random coincidences for quantitative cardiac PET studies using 3D oxygen-15 water scans

    NASA Astrophysics Data System (ADS)

    Bouchareb, Y.; Thielemans, K.; Spinks, T.; Rimoldi, O.; Camici, P. G.

    2006-03-01

    The effect of random coincidences estimation methods on the quantitative accuracy of iterative and analytic reconstruction methods to determine myocardial blood flow (MBF) in PET studies using H II 15O has been investigated. Dynamic scans were acquired on the EXACT3D PET scanner on pigs after H II 15O injection (resting and dipyridamoleinduced stress). Radioactive microspheres (MS) were used to provide a "gold standard" of MBF values. The online subtraction (OS) and maximum likelihood (ML) methods for estimating randoms were combined with (i) 3D-RP, (ii) FORE + attenuation-weighted OSEM, (iii) FORE-FBP and (iv) 3D-OSEM. Factor images were generated and resliced to short axis images; 16 ROIs were defined in the left myocardium and 2 ROIs in the left and right cavities. ROIs were projected onto the dynamic images to extract time-activity-curves, which were then fitted to a single compartment model to estimate absolute MBF. Microsphere measurements were obtained in a similar way and 64 pairs of measurements were made. The ML method improved the SNR of 3D-RP, FORE-FBP, FORE-OSEM, and 3D-OSEM by 8%, 8%, 7% and 3% respectively. Compared to the OS method, the ML method improved the accuracy of coronary flow reserve values of 3DOSEM, 3D-RP, FORE-OSEM and FORE-FBP by 9%, 7%, 1% and 3% respectively. Regression analysis provided better correlation with 3D-OSEM and FORE-OSEM when combined with the ML method. We conclude that the ML method for estimating randoms combined with 3D-OSEM and FORE-OSEM delivers the best performance for absolute quantification of MBF using H II 15O when compared with microsphere measurements.

  11. 3D laser scanning and modelling of the Dhow heritage for the Qatar National Museum

    NASA Astrophysics Data System (ADS)

    Wetherelt, A.; Cooper, J. P.; Zazzaro, C.

    2014-08-01

    Curating boats can be difficult. They are complex structures, often demanding to conserve whether in or out of the water; they are usually large, difficult to move on land, and demanding of gallery space. Communicating life on board to a visiting public in the terra firma context of a museum can be difficult. Boats in their native environment are inherently dynamic artifacts. In a museum they can be static and divorced from the maritime context that might inspire engagement. New technologies offer new approaches to these problems. 3D laser scanning and digital modeling offers museums a multifaceted means of recording, monitoring, studying and communicating watercraft in their care. In this paper we describe the application of 3D laser scanning and subsequent digital modeling. Laser scans were further developed using computer-generated imagery (CGI) modeling techniques to produce photorealistic 3D digital models for development into interactive, media-based museum displays. The scans were also used to generate 2D naval lines and orthographic drawings as a lasting curatorial record of the dhows held by the National Museum of Qatar.

  12. Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry

    PubMed Central

    Adamson, Justus; Newton, Joseph; Yang, Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana

    2012-01-01

    Purpose: To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T&O) applicator using Monte Carlo calculation and 3D dosimetry. Methods: For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 × 109 photon histories from a 137Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for 137Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE® dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5–8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5° increments, and a 3D distribution was reconstructed with a (0.05 cm)3 isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T&O implant plan. Results: The systematic difference in bucket angle relative to the nominal ovoid angle (105°) was 3.1°–4.7°. A systematic difference in bucket angle of 1°, 5°, and 10° caused a 1% ± 0.1%, 1.7% ± 0.4%, and 2.6% ± 0.7% increase in rectal dose, respectively, with smaller effect to dose to

  13. Commissioning a CT-compatible LDR tandem and ovoid applicator using Monte Carlo calculation and 3D dosimetry

    SciTech Connect

    Adamson, Justus; Newton, Joseph; Yang Yun; Steffey, Beverly; Cai, Jing; Adamovics, John; Oldham, Mark; Chino, Junzo; Craciunescu, Oana

    2012-07-15

    Purpose: To determine the geometric and dose attenuation characteristics of a new commercially available CT-compatible LDR tandem and ovoid (T and O) applicator using Monte Carlo calculation and 3D dosimetry. Methods: For geometric characterization, we quantified physical dimensions and investigated a systematic difference found to exist between nominal ovoid angle and the angle at which the afterloading buckets fall within the ovoid. For dosimetric characterization, we determined source attenuation through asymmetric gold shielding in the buckets using Monte Carlo simulations and 3D dosimetry. Monte Carlo code MCNP5 was used to simulate 1.5 Multiplication-Sign 10{sup 9} photon histories from a {sup 137}Cs source placed in the bucket to achieve statistical uncertainty of 1% at a 6 cm distance. For 3D dosimetry, the distribution about an unshielded source was first measured to evaluate the system for {sup 137}Cs, after which the distribution was measured about sources placed in each bucket. Cylindrical PRESAGE{sup Registered-Sign} dosimeters (9.5 cm diameter, 9.2 cm height) with a central channel bored for source placement were supplied by Heuris Inc. The dosimeters were scanned with the Duke Large field of view Optical CT-Scanner before and after delivering a nominal dose at 1 cm of 5-8 Gy. During irradiation the dosimeter was placed in a water phantom to provide backscatter. Optical CT scan time lasted 15 min during which 720 projections were acquired at 0.5 Degree-Sign increments, and a 3D distribution was reconstructed with a (0.05 cm){sup 3} isotropic voxel size. The distributions about the buckets were used to calculate a 3D distribution of transmission rate through the bucket, which was applied to a clinical CT-based T and O implant plan. Results: The systematic difference in bucket angle relative to the nominal ovoid angle (105 Degree-Sign ) was 3.1 Degree-Sign -4.7 Degree-Sign . A systematic difference in bucket angle of 1 Degree-Sign , 5 Degree-Sign , and

  14. 3-D ice shape measurements using mid-infrared laser scanning.

    PubMed

    Gong, Xiaoliang; Bansmer, Stephan

    2015-02-23

    A general approach based on mid-infrared (MIR) laser scanning is proposed to measure the 3-D ice shape no matter whether the ice is composed of clear ice, rime ice, mixed ice, or even supercooled water droplets or films. This is possible because MIR radiation penetrates ice and water only within a depth of less than 10 micrometers. First, an MIR laser point scanning technique is implemented and verified on transparent glass and clear ice. Then, to improve efficiency, an MIR laser line scanning method is developed and validated on different models. At last, several sequential MIR laser line scans are applied to trace the 3-D shape evolution of the continuous ice accretion on an airfoil in an icing wind tunnel. The ice growth process can be well observed in the results. The MIR scan shows a good agreement with the traditional visible laser scan on a plastic replication of the final ice shape made by the mold and casting method. PMID:25836526

  15. 3D visualization of biomedical CT images based on OpenGL and VRML techniques

    NASA Astrophysics Data System (ADS)

    Yin, Meng; Luo, Qingming; Xia, Fuhua

    2002-04-01

    Current high-performance computers and advanced image processing capabilities have made the application of three- dimensional visualization objects in biomedical computer tomographic (CT) images facilitate the researches on biomedical engineering greatly. Trying to cooperate with the update technology using Internet, where 3D data are typically stored and processed on powerful servers accessible by using TCP/IP, we should hold the results of the isosurface be applied in medical visualization generally. Furthermore, this project is a future part of PACS system our lab is working on. So in this system we use the 3D file format VRML2.0, which is used through the Web interface for manipulating 3D models. In this program we implemented to generate and modify triangular isosurface meshes by marching cubes algorithm. Then we used OpenGL and MFC techniques to render the isosurface and manipulating voxel data. This software is more adequate visualization of volumetric data. The drawbacks are that 3D image processing on personal computers is rather slow and the set of tools for 3D visualization is limited. However, these limitations have not affected the applicability of this platform for all the tasks needed in elementary experiments in laboratory or data preprocessed.

  16. Combining laser scan and photogrammetry for 3D object modeling using a single digital camera

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Zhang, Hong; Zhang, Xiangwei

    2009-07-01

    In the fields of industrial design, artistic design and heritage conservation, physical objects are usually digitalized by reverse engineering through some 3D scanning methods. Laser scan and photogrammetry are two main methods to be used. For laser scan, a video camera and a laser source are necessary, and for photogrammetry, a digital still camera with high resolution pixels is indispensable. In some 3D modeling tasks, two methods are often integrated to get satisfactory results. Although many research works have been done on how to combine the results of the two methods, no work has been reported to design an integrated device at low cost. In this paper, a new 3D scan system combining laser scan and photogrammetry using a single consumer digital camera is proposed. Nowadays there are many consumer digital cameras, such as Canon EOS 5D Mark II, they usually have features of more than 10M pixels still photo recording and full 1080p HD movie recording, so a integrated scan system can be designed using such a camera. A square plate glued with coded marks is used to place the 3d objects, and two straight wood rulers also glued with coded marks can be laid on the plate freely. In the photogrammetry module, the coded marks on the plate make up a world coordinate and can be used as control network to calibrate the camera, and the planes of two rulers can also be determined. The feature points of the object and the rough volume representation from the silhouettes can be obtained in this module. In the laser scan module, a hand-held line laser is used to scan the object, and the two straight rulers are used as reference planes to determine the position of the laser. The laser scan results in dense points cloud which can be aligned together automatically through calibrated camera parameters. The final complete digital model is obtained through a new a patchwise energy functional method by fusion of the feature points, rough volume and the dense points cloud. The design

  17. HOSVD-Based 3D Active Appearance Model: Segmentation of Lung Fields in CT Images.

    PubMed

    Wang, Qingzhu; Kang, Wanjun; Hu, Haihui; Wang, Bin

    2016-07-01

    An Active Appearance Model (AAM) is a computer vision model which can be used to effectively segment lung fields in CT images. However, the fitting result is often inadequate when the lungs are affected by high-density pathologies. To overcome this problem, we propose a Higher-order Singular Value Decomposition (HOSVD)-based Three-dimensional (3D) AAM. An evaluation was performed on 310 diseased lungs form the Lung Image Database Consortium Image Collection. Other contemporary AAMs operate directly on patterns represented by vectors, i.e., before applying the AAM to a 3D lung volume,it has to be vectorized first into a vector pattern by some technique like concatenation. However, some implicit structural or local contextual information may be lost in this transformation. According to the nature of the 3D lung volume, HOSVD is introduced to represent and process the lung in tensor space. Our method can not only directly operate on the original 3D tensor patterns, but also efficiently reduce the computer memory usage. The evaluation resulted in an average Dice coefficient of 97.0 % ± 0.59 %, a mean absolute surface distance error of 1.0403 ± 0.5716 mm, a mean border positioning errors of 0.9187 ± 0.5381 pixel, and a Hausdorff Distance of 20.4064 ± 4.3855, respectively. Experimental results showed that our methods delivered significant and better segmentation results, compared with the three other model-based lung segmentation approaches, namely 3D Snake, 3D ASM and 3D AAM. PMID:27277277

  18. 3D imaging of the early embryonic chicken heart with focused ion beam scanning electron microscopy

    PubMed Central

    Rennie, Monique Y.; Gahan, Curran G.; López, Claudia S.; Thornburg, Kent L.; Rugonyi, Sandra

    2015-01-01

    Early embryonic heart development is a period of dynamic growth and remodeling, with rapid changes occurring at the tissue, cell, and subcellular levels. A detailed understanding of the events that establish the components of the heart wall has been hampered by a lack of methodologies for three dimensional (3D), high-resolution imaging. Focused ion beam-scanning electron microscopy (FIB-SEM) is a novel technology for imaging 3D tissue volumes at the subcellular level. FIB-SEM alternates between imaging the block face with a scanning electron beam and milling away thin sections of tissue with a focused ion beam, allowing for collection and analysis of 3D data. FIB-SEM was used to image the three layers of the day 4 chicken embryo heart: myocardium, cardiac jelly, and endocardium. Individual images obtained with FIB-SEM were comparable in quality and resolution to those obtained with transmission electron microscopy (TEM). Up to 1100 serial images were obtained in 4 nm increments at 4.88 nm resolution, and image stacks were aligned to create volumes 800–1500 μm3 in size. Segmentation of organelles revealed their organization and distinct volume fractions between cardiac wall layers. We conclude that FIB-SEM is a powerful modality for 3D subcellular imaging of the embryonic heart wall. PMID:24742339

  19. Geomorphometric analysis of cave ceiling channels mapped with 3-D terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Gallay, Michal; Hochmuth, Zdenko; Kaňuk, Ján; Hofierka, Jaroslav

    2016-05-01

    The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.

  20. Virtual rough samples to test 3D nanometer-scale scanning electron microscopy stereo photogrammetry

    NASA Astrophysics Data System (ADS)

    Villarrubia, J. S.; Tondare, V. N.; Vladár, A. E.

    2016-03-01

    The combination of scanning electron microscopy for high spatial resolution, images from multiple angles to provide 3D information, and commercially available stereo photogrammetry software for 3D reconstruction offers promise for nanometer-scale dimensional metrology in 3D. A method is described to test 3D photogrammetry software by the use of virtual samples—mathematical samples from which simulated images are made for use as inputs to the software under test. The virtual sample is constructed by wrapping a rough skin with any desired power spectral density around a smooth near-trapezoidal line with rounded top corners. Reconstruction is performed with images simulated from different angular viewpoints. The software's reconstructed 3D model is then compared to the known geometry of the virtual sample. Three commercial photogrammetry software packages were tested. Two of them produced results for line height and width that were within close to 1 nm of the correct values. All of the packages exhibited some difficulty in reconstructing details of the surface roughness.

  1. Doctors Should Bone Up on CT Scan Cancer Risks

    MedlinePlus

    ... fullstory_159909.html Doctors Should Bone Up on CT Scan Cancer Risks Many not aware of exact radiation ... July 15, 2016 (HealthDay News) -- Doctors routinely order CT scans as diagnostic tools. But many are ill-informed ...

  2. Audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI

    NASA Astrophysics Data System (ADS)

    Lee, D.; Greer, P. B.; Arm, J.; Keall, P.; Kim, T.

    2014-03-01

    The purpose of this study was to test the hypothesis that audiovisual (AV) biofeedback can improve image quality and reduce scan time for respiratory-gated 3D thoracic MRI. For five healthy human subjects respiratory motion guidance in MR scans was provided using an AV biofeedback system, utilizing real-time respiratory motion signals. To investigate the improvement of respiratory-gated 3D MR images between free breathing (FB) and AV biofeedback (AV), each subject underwent two imaging sessions. Respiratory-related motion artifacts and imaging time were qualitatively evaluated in addition to the reproducibility of external (abdominal) motion. In the results, 3D MR images in AV biofeedback showed more anatomic information such as a clear distinction of diaphragm, lung lobes and sharper organ boundaries. The scan time was reduced from 401±215 s in FB to 334±94 s in AV (p-value 0.36). The root mean square variation of the displacement and period of the abdominal motion was reduced from 0.4±0.22 cm and 2.8±2.5 s in FB to 0.1±0.15 cm and 0.9±1.3 s in AV (p-value of displacement <0.01 and p-value of period 0.12). This study demonstrated that audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI. These results suggest that AV biofeedback has the potential to be a useful motion management tool in medical imaging and radiation therapy procedures.

  3. Can 3D-CT angiography (3D-CTA) replace conventional catheter angiography in ruptured aneurysm surgery? Our experience with 162 cases.

    PubMed

    Matsumoto, Masato; Kasuya, Hiromichi; Sato, Taku; Endo, Yuji; Sakuma, Jun; Suzuki, Kyouichi; Sasaki, Tatsuya; Kodama, Namio

    2007-12-01

    In this communication, we studied whether 3D-CT angiography (3D CTA) gives us enough information for a safe operation without those from conventional catheter angiography (CCA) in patients with ruptured aneurysms. Between December 1996 and September 2005, we treated 162 consecutive patients with ruptured aneurysms in the acute stage based on 3D-CTA findings. One hundred sixty-two ruptured aneurysms, including 64 associated unruptured aneurysms, were detected using 3D-CTA. CCA was performed in nine (5.6%) of the 162 patients after 3D-CTA. They were four dissecting vertebral artery aneurysms, two basilar tip aneurysms, one basilar artery-superior cerebellar artery (BA-SCA), one previously clipped BA-SCA and one internal carotid-posterior communicating artery aneurysm. All ruptured aneurysms confirmed at surgery were treated successfully. The lack of information on CCA did not lead any neurological deficits or difficulties in the surgical procedure. 3D-CTA was of high diagnostic value compatible with CCA and yielded important information such as the configuration of the aneurysmal sac and neck, calcification in the aneurysmal wall, and the aneurysms' anatomic relation with adjacent vessels and bone structures. We suggest that 3D-CTA can replace CCA in the diagnosis of ruptured aneurysms and that most of ruptured aneurysms can be operated by using only 3D-CTA without CCA. PMID:18402288

  4. Multimodal imaging of the human temporal bone: A comparison of CT and optical scanning techniques

    NASA Astrophysics Data System (ADS)

    Voie, Arne H.; Whiting, Bruce; Skinner, Margaret; Neely, J. Gail; Lee, Kenneth; Holden, Tim; Brunsden, Barry

    2003-10-01

    A collaborative effort between Washington University in St. Louis and Spencer Technologies in Seattle, WA has been undertaken to create a multimodal 3D reconstruction of the human cochlea and vestibular system. The goal of this project is to improve the accuracy of in vivo CT reconstructions of implanted cochleae, and to expand the knowledge of high-resolution anatomical detail provided by orthogonal-plane optical sectioning (OPFOS). At WUSL, computed tomography (CT) images of the cochlea are used to determine the position of cochlear implant electrodes relative to target auditory neurons. The cochlear implant position is determined using pre- and post-operative CT scans. The CT volumes are cross-registered to align the semicircular canals and internal auditory canal, which have a unique configuration in 3-D space. The head of a human body donor was scanned with a clinical CT device, after which the temporal bones were removed, fixed in formalin and trimmed prior to scanning with a laboratory Micro CT scanner. Following CT, the temporal bones were sent to the OPFOS Imaging Lab at Spencer Technologies for a further analysis. 3-D reconstructions of CT and OPFOS imaging modalities were compared, and results are presented. [Work supported by NIDCD Grants R44-03623-5 and R01-00581-13.

  5. Segmentation of bone structures in 3D CT images based on continuous max-flow optimization

    NASA Astrophysics Data System (ADS)

    Pérez-Carrasco, J. A.; Acha-Piñero, B.; Serrano, C.

    2015-03-01

    In this paper an algorithm to carry out the automatic segmentation of bone structures in 3D CT images has been implemented. Automatic segmentation of bone structures is of special interest for radiologists and surgeons to analyze bone diseases or to plan some surgical interventions. This task is very complicated as bones usually present intensities overlapping with those of surrounding tissues. This overlapping is mainly due to the composition of bones and to the presence of some diseases such as Osteoarthritis, Osteoporosis, etc. Moreover, segmentation of bone structures is a very time-consuming task due to the 3D essence of the bones. Usually, this segmentation is implemented manually or with algorithms using simple techniques such as thresholding and thus providing bad results. In this paper gray information and 3D statistical information have been combined to be used as input to a continuous max-flow algorithm. Twenty CT images have been tested and different coefficients have been computed to assess the performance of our implementation. Dice and Sensitivity values above 0.91 and 0.97 respectively were obtained. A comparison with Level Sets and thresholding techniques has been carried out and our results outperformed them in terms of accuracy.

  6. Diaphragm dome surface segmentation in CT data sets: a 3D active appearance model approach

    NASA Astrophysics Data System (ADS)

    Beichel, Reinhard; Gotschuli, Georg; Sorantin, Erich; Leberl, Franz W.; Sonka, Milan

    2002-05-01

    Knowledge about the location of the diaphragm dome surface, which separates the lungs and the heart from the abdominal cavity, is of vital importance for applications like automated segmentation of adjacent organs (e.g., liver) or functional analysis of the respiratory cycle. We present a new 3D Active Appearance Model (AAM) approach to segmentation of the top layer of the diaphragm dome. The 3D AAM consists of three parts: a 2D closed curve (reference curve), an elevation image and texture layers. The first two parts combined represent 3D shape information and the third part image intensity of the diaphragm dome and the surrounding layers. Differences in height between dome voxels and a reference plane are stored in the elevation image. The reference curve is generated by a parallel projection of the diaphragm dome outline in the axial direction. Landmark point placement is only done on the (2D) reference curve, which can be seen as the bounding curve of the elevation image. Matching is based on a gradient-descent optimization process and uses image intensity appearance around the actual dome shape. Results achieved in 60 computer generated phantom data sets show a high degree of accuracy (positioning error -0.07+/-1.29 mm). Validation using real CT data sets yielded a positioning error of -0.16+/-2.95 mm. Additional training and testing on in-vivo CT image data is ongoing.

  7. X-Ray Nanofocus CT: Visualising Of Internal 3D-Structures With Submicrometer Resolution

    NASA Astrophysics Data System (ADS)

    Weinekoetter, Christian

    2008-09-01

    High-resolution X-ray Computed Tomography (CT) allows the visualization and failure analysis of the internal micro structure of objects—even if they have complicated 3D-structures where 2D X-ray microscopy would give unclear information. During the past several years, computed tomography has progressed to higher resolution and quicker reconstruction of the 3D-volume. Most recently it even allows a three-dimensional look into the inside of materials with submicron resolution. With the use of nanofocus® tube technology, nanoCT®-systems are pushing forward into application fields that were exclusive to high cost and rare available synchrotron techniques. The study was performed with the new nanotom, a very compact laboratory system which allows the analysis of samples up to 120 mm in diameter and weighing up to 1 kg with exceptional voxel-resolution down to <500 nm (<0.5 microns). It is the first 180 kV nanofocus® computed tomography system in the world which is tailored specifically to the highest-resolution applications in the fields of material science, micro electronics, geology and biology. Therefore it is particularly suitable for nanoCT-examinations e.g. of synthetic materials, metals, ceramics, composite materials, mineral and organic samples. There are a few physical effects influencing the CT quality, such as beam-hardening within the sample or ring-artefacts, which can not be completely avoided. To optimize the quality of high resolution 3D volumes, the nanotom® includes a variety of effective software tools to reduce ring-artefacts and correct beam hardenings or drift effects which occurred during data acquisition. The resulting CT volume data set can be displayed in various ways, for example by virtual slicing and sectional views in any direction of the volume. By the fact that this requires only a mouse click, this technique will substitute destructive mechanical slicing and cutting in many applications. The initial CT results obtained with the

  8. Optical CT scanner for in-air readout of gels for external radiation beam 3D dosimetry.

    PubMed

    Ramm, Daniel; Rutten, Thomas P; Shepherd, Justin; Bezak, Eva

    2012-06-21

    Optical CT scanners for a 3D readout of externally irradiated radiosensitive hydrogels currently require the use of a refractive index (RI) matching liquid bath to obtain suitable optical ray paths through the gel sample to the detector. The requirement for a RI matching liquid bath has been negated by the design of a plastic cylindrical gel container that provides parallel beam geometry through the gel sample for the majority of the projection. The design method can be used for various hydrogels. Preliminary test results for the prototype laser beam scanner with ferrous xylenol-orange gel show geometric distortion of 0.2 mm maximum, spatial resolution limited to beam spot size of about 0.4 mm and 0.8% noise (1 SD) for a uniform irradiation. Reconstruction of a star pattern irradiated through the cylinder walls demonstrates the suitability for external beam applications. The extremely simple and cost-effective construction of this optical CT scanner, together with the simplicity of scanning gel samples without RI matching fluid increases the feasibility of using 3D gel dosimetry for clinical external beam dose verifications. PMID:22644104

  9. Pulmonary nodule classification based on CT density distribution using 3D thoracic CT images

    NASA Astrophysics Data System (ADS)

    Kawata, Yoshiki; Niki, Noboru; Ohamatsu, Hironobu; Kusumoto, Masahiko; Kakinuma, Ryutaro; Mori, Kiyoshi; Yamada, Kozo; Nishiyama, Hiroyuki; Eguchi, Kenji; Kaneko, Masahiro; Moriyama, Noriyuki

    2004-04-01

    Computer-aided diagnosis (CAD) has been investigated to provide physicians with quantitative information, such as estimates of the malignant likelihood, to aid in the classification of abnormalities detected at screening of lung cancers. The purpose of this study is to develop a method for classifying nodule density patterns that provides information with respect to nodule statuses such as lesion stage. This method consists of three steps, nodule segmentation, histogram analysis of CT density inside nodule, and classifying nodules into five types based on histogram patterns. In this paper, we introduce a two-dimensional (2-D) joint histogram with respect to distance from nodule center and CT density inside nodule and explore numerical features with respect to shape and position of the joint histogram.

  10. Multimodal visualization of 3D enhanced MRI and CT of acoustic schwannoma and related structures

    NASA Astrophysics Data System (ADS)

    Kucharski, Tomasz; Kujawinska, Malgorzata; Niemczyk, Kazimierz; Marchel, Andrzej

    2005-09-01

    According to the necessity of supporting vestibular schwannoma surgery, there is a demand to develop a convenient method of medical data visualization. The process of making choice of optimal operating access way has been uncomfortable for a surgeon so far, because there has been a necessity of analyzing two independent 3D images series (CT -bone tissues visible, MRI - soft tissues visible) in the region of ponto-cerebellar angle tumors. The authors propose a solution that will improve this process. The system used is equipped with stereoscopic helmet mounted display. It allows merged CT and MRI data representing tissues in the region of of ponto-cerebellar angle to be visualized in stereoscopic way. The process of data preparation for visualization includes: -automated segmentation algorithms, -different types of 3D images (CT, MRI) fusion. The authors focused on the development of novel algorithms for segmentation of vestibular schwannoma. It is important and difficult task due to different types of tumors and their inhomogeneous character dependent on growth models. The authors propose algorithms based on histogram spectrum and multimodal character of MRI imaging (T1 and T2 modes). However due to a variety of objects the library of algorithms with specific modifications matching to selected types of images is proposed. The applicability and functionality of the algorithms and library was proved on the series of data delivered by Warsaw Central Medical University Hospital.

  11. Analysis of the Possibilities of Using Low-Cost Scanning System in 3d Modeling

    NASA Astrophysics Data System (ADS)

    Kedzierski, M.; Wierzbickia, D.; Fryskowska, A.; Chlebowska, B.

    2016-06-01

    The laser scanning technique is still a very popular and fast growing method of obtaining information on modeling 3D objects. The use of low-cost miniature scanners creates new opportunities for small objects of 3D modeling based on point clouds acquired from the scan. The same, the development of accuracy and methods of automatic processing of this data type is noticeable. The article presents methods of collecting raw datasets in the form of a point-cloud using a low-cost ground-based laser scanner FabScan. As part of the research work 3D scanner from an open source FabLab project was constructed. In addition, the results for the analysis of the geometry of the point clouds obtained by using a low-cost laser scanner were presented. Also, some analysis of collecting data of different structures (made of various materials such as: glass, wood, paper, gum, plastic, plaster, ceramics, stoneware clay etc. and of different shapes: oval and similar to oval and prism shaped) have been done. The article presents two methods used for analysis: the first one - visual (general comparison between the 3D model and the real object) and the second one - comparative method (comparison between measurements on models and scanned objects using the mean error of a single sample of observations). The analysis showed, that the low-budget ground-based laser scanner FabScan has difficulties with collecting data of non-oval objects. Items built of glass painted black also caused problems for the scanner. In addition, the more details scanned object contains, the lower the accuracy of the collected point-cloud is. Nevertheless, the accuracy of collected data (using oval-straight shaped objects) is satisfactory. The accuracy, in this case, fluctuates between ± 0,4 mm and ± 1,0 mm whereas when using more detailed objects or a rectangular shaped prism the accuracy is much more lower, between 2,9 mm and ± 9,0 mm. Finally, the publication presents the possibility (for the future expansion of

  12. Overbeaming and overlapping of volume-scan CT with tube current modulation in a 320-detector row CT scanner

    NASA Astrophysics Data System (ADS)

    Liao, Ying-Lan; Chen, Yan-Shi; Lai, Nan-Ku; Chuang, Keh-Shih; Tsai, Hui-Yu

    2014-11-01

    The purpose of this study was to evaluate the performance of volume scan tube current modulation (VS-ATCM) with adaptive iterative dose reduction 3D (AIDR3D) technique in abdomen CT examinations. We scanned an elliptical cone-shaped phantom utilizing AIDR3D technique combined with VS-ATCM mode in a 320-detector row CT scanner. The image noise distributions with conventional filtered back-projction (FBP) technique and those with AIDR3D technique were compared. The radiation dose profile and tube current time product (mAs) in three noise levels of VS-ATCM modes were compared. The radiation beam profiles of five preset scan lengths were measured using Gafchromic film strips to assess the effects of overbeaming and everlapping. The results indicated that the image noises with AIDR3D technique was 13-74% lower than those in FBP technique. The mAs distributions can be a prediction for various abdominal sizes when undergoing a VS-ATCM mode scan. Patients can receive the radiation dose of overbeaming and overlapping during the VS-ATCM mode scans.

  13. TU-F-12A-05: Sensitivity of Textural Features to 3D Vs. 4D FDG-PET/CT Imaging in NSCLC Patients

    SciTech Connect

    Yang, F; Nyflot, M; Bowen, S; Kinahan, P; Sandison, G

    2014-06-15

    Purpose: Neighborhood Gray-level difference matrices (NGLDM) based texture parameters extracted from conventional (3D) 18F-FDG PET scans in patients with NSCLC have been previously shown to associate with response to chemoradiation and poorer patient outcome. However, the change in these parameters when utilizing respiratory-correlated (4D) FDG-PET scans has not yet been characterized for NSCLC. The Objectives: of this study was to assess the extent to which NGLDM-based texture parameters on 4D PET images vary with reference to values derived from 3D scans in NSCLC. Methods: Eight patients with newly diagnosed NSCLC treated with concomitant chemoradiotherapy were included in this study. 4D PET scans were reconstructed with OSEM-IR in 5 respiratory phase-binned images and corresponding CT data of each phase were employed for attenuation correction. NGLDM-based texture features, consisting of coarseness, contrast, busyness, complexity and strength, were evaluated for gross tumor volumes defined on 3D/4D PET scans by radiation oncologists. Variation of the obtained texture parameters over the respiratory cycle were examined with respect to values extracted from 3D scans. Results: Differences between texture parameters derived from 4D scans at different respiratory phases and those extracted from 3D scans ranged from −30% to 13% for coarseness, −12% to 40% for contrast, −5% to 50% for busyness, −7% to 38% for complexity, and −43% to 20% for strength. Furthermore, no evident correlations were observed between respiratory phase and 4D scan texture parameters. Conclusion: Results of the current study showed that NGLDM-based texture parameters varied considerably based on choice of 3D PET and 4D PET reconstruction of NSCLC patient images, indicating that standardized image acquisition and analysis protocols need to be established for clinical studies, especially multicenter clinical trials, intending to validate prognostic values of texture features for NSCLC.

  14. Recovering 3D tumor locations from 2D bioluminescence images and registration with CT images

    NASA Astrophysics Data System (ADS)

    Huang, Xiaolei; Metaxas, Dimitris N.; Menon, Lata G.; Mayer-Kuckuk, Philipp; Bertino, Joseph R.; Banerjee, Debabrata

    2006-02-01

    In this paper, we introduce a novel and efficient algorithm for reconstructing the 3D locations of tumor sites from a set of 2D bioluminescence images which are taken by a same camera but after continually rotating the object by a small angle. Our approach requires a much simpler set up than those using multiple cameras, and the algorithmic steps in our framework are efficient and robust enough to facilitate its use in analyzing the repeated imaging of a same animal transplanted with gene marked cells. In order to visualize in 3D the structure of the tumor, we also co-register the BLI-reconstructed crude structure with detailed anatomical structure extracted from high-resolution microCT on a single platform. We present our method using both phantom studies and real studies on small animals.

  15. First 3D reconstruction of the rhizocephalan root system using MicroCT

    NASA Astrophysics Data System (ADS)

    Noever, Christoph; Keiler, Jonas; Glenner, Henrik

    2016-07-01

    Parasitic barnacles (Cirripedia: Rhizocephala) are highly specialized parasites of crustaceans. Instead of an alimentary tract for feeding they utilize a system of roots, which infiltrates the body of their hosts to absorb nutrients. Using X-ray micro computer tomography (MicroCT) and computer-aided 3D-reconstruction, we document the spatial organization of this root system, the interna, inside the intact host and also demonstrate its use for morphological examinations of the parasites reproductive part, the externa. This is the first 3D visualization of the unique root system of the Rhizocephala in situ, showing how it is related to the inner organs of the host. We investigated the interna from different parasitic barnacles of the family Peltogastridae, which are parasitic on anomuran crustaceans. Rhizocephalan parasites of pagurid hermit crabs and lithodid crabs were analysed in this study.

  16. 3D segmentation of lung CT data with graph-cuts: analysis of parameter sensitivities

    NASA Astrophysics Data System (ADS)

    Cha, Jung won; Dunlap, Neal; Wang, Brian; Amini, Amir

    2016-03-01

    Lung boundary image segmentation is important for many tasks including for example in development of radiation treatment plans for subjects with thoracic malignancies. In this paper, we describe a method and parameter settings for accurate 3D lung boundary segmentation based on graph-cuts from X-ray CT data1. Even though previously several researchers have used graph-cuts for image segmentation, to date, no systematic studies have been performed regarding the range of parameter that give accurate results. The energy function in the graph-cuts algorithm requires 3 suitable parameter settings: K, a large constant for assigning seed points, c, the similarity coefficient for n-links, and λ, the terminal coefficient for t-links. We analyzed the parameter sensitivity with four lung data sets from subjects with lung cancer using error metrics. Large values of K created artifacts on segmented images, and relatively much larger value of c than the value of λ influenced the balance between the boundary term and the data term in the energy function, leading to unacceptable segmentation results. For a range of parameter settings, we performed 3D image segmentation, and in each case compared the results with the expert-delineated lung boundaries. We used simple 6-neighborhood systems for n-link in 3D. The 3D image segmentation took 10 minutes for a 512x512x118 ~ 512x512x190 lung CT image volume. Our results indicate that the graph-cuts algorithm was more sensitive to the K and λ parameter settings than to the C parameter and furthermore that amongst the range of parameters tested, K=5 and λ=0.5 yielded good results.

  17. Long-range laser scanning and 3D imaging for the Gneiss quarries survey

    NASA Astrophysics Data System (ADS)

    Schenker, Filippo Luca; Spataro, Alessio; Pozzoni, Maurizio; Ambrosi, Christian; Cannata, Massimiliano; Günther, Felix; Corboud, Federico

    2016-04-01

    In Canton Ticino (Southern Switzerland), the exploitation of natural stone, mostly gneisses, is an important activity of valley's economies. Nowadays, these economic activities are menaced by (i) the exploitation costs related to geological phenomena such as fractures, faults and heterogeneous rocks that hinder the processing of the stone product, (ii) continuously changing demand because of the evolving natural stone fashion and (iii) increasing administrative limits and rules acting to protect the environment. Therefore, the sustainable development of the sector for the next decades needs new and effective strategies to regulate and plan the quarries. A fundamental step in this process is the building of a 3D geological model of the quarries to constrain the volume of commercial natural stone and the volume of waste. In this context, we conducted Terrestrial Laser Scanning surveys of the quarries in the Maggia Valley to obtain a detailed 3D topography onto which the geological units were mapped. The topographic 3D model was obtained with a long-range laser scanning Riegl VZ4000 that can measure from up to 4 km of distance with a speed of 147,000 points per second. It operates with the new V-line technology, which defines the surface relief by sensing differentiated signals (echoes), even in the presence of obstacles such as vegetation. Depending on the esthetics of the gneisses, we defined seven types of natural stones that, together with faults and joints, were mapped onto the 3D models of the exploitation sites. According to the orientation of the geological limits and structures, we projected the different rock units and fractures into the excavation front. This way, we obtained a 3D geological model from which we can quantitatively estimate the volume of the seven different natural stones (with different commercial value) and waste (with low commercial value). To verify the 3D geological models and to quantify exploited rock and waste volumes the same

  18. Development of 3D-CT System Using MIRRORCLE-6X

    SciTech Connect

    Sasaki, M.; Yamada, H.; Takaku, J.; Hirai, T.

    2007-03-30

    The technique of computed tomography (CT) has been used in various fields, such as medical, non-destructive testing (NDT), baggage checking, etc. A 3D-CT system based on the portable synchrotron 'MIRRORCLE'-series will be a novel instrument for these fields. The hard x-rays generated from the 'MIRRORCLE' have a wide energy spectrum. Light and thin materials create absorption and refraction contrast in x-ray images by the lower energy component (< 60 keV), and heavy and thick materials create absorption contrast by the higher energy component. In addition, images with higher resolutions can be obtained using 'MIRRORCLE' with a small source size of micron order. Thus, high resolution 3D-CT images of specimens containing both light and heavy materials can be obtained using 'MIRRORCLE' and a 2D-detector with a wide dynamic range. In this paper, the development and output of a 3D-CT system using the 'MIRRORCLE-6X' and a flat panel detector are reported.A 3D image of a piece of concrete was obtained. The detector was a flat panel detector (VARIAN, PAXSCAN2520) with 254 {mu}m pixel size. The object and the detector were set at 50 cm and 250 cm respectively from the x-ray source, so that the magnification was 5x. The x-ray source was a 50 {mu}m Pt rod. The rotation stage and the detector were remote-controlled using a computer, which was originally created using LabView and Visual Basic software. The exposure time was about 20 minutes. The reconstruction calculation was based on the Feldkamp algorithm, and the pixel size was 50 {mu}m. We could observe sub-mm holes and density differences in the object. Thus, the 'MIRRORCLE-CV' with 1MeV electron energy, which has same x-ray generation principles, will be an excellent x-ray source for medical diagnostics and NDT.

  19. 3D patient-specific model of the tibia from CT for orthopedic use

    PubMed Central

    González-Carbonell, Raide A.; Ortiz-Prado, Armando; Jacobo-Armendáriz, Victor H.; Cisneros-Hidalgo, Yosbel A.; Alpízar-Aguirre, Armando

    2015-01-01

    Objectives 3D patient-specific model of the tibia is used to determine the torque needed to initialize the tibial torsion correction. Methods The finite elements method is used in the biomechanical modeling of tibia. The geometric model of the tibia is obtained from CT images. The tibia is modeled as an anisotropic material with non-homogeneous mechanical properties. Conclusions The maximum stress is located in the shaft of tibia diaphysis. With both meshes are obtained similar results of stresses and displacements. For this patient-specific model, the torque must be greater than 30 Nm to initialize the correction of tibial torsion deformity. PMID:25829755

  20. Automated detection system for pulmonary emphysema on 3D chest CT images

    NASA Astrophysics Data System (ADS)

    Hara, Takeshi; Yamamoto, Akira; Zhou, Xiangrong; Iwano, Shingo; Itoh, Shigeki; Fujita, Hiroshi; Ishigaki, Takeo

    2004-05-01

    An automatic extraction of pulmonary emphysema area on 3-D chest CT images was performed using an adaptive thresholding technique. We proposed a method to estimate the ratio of the emphysema area to the whole lung volume. We employed 32 cases (15 normal and 17 abnormal) which had been already diagnosed by radiologists prior to the study. The ratio in all the normal cases was less than 0.02, and in abnormal cases, it ranged from 0.01 to 0.26. The effectiveness of our approach was confirmed through the results of the present study.

  1. Grammar-based Automatic 3D Model Reconstruction from Terrestrial Laser Scanning Data

    NASA Astrophysics Data System (ADS)

    Yu, Q.; Helmholz, P.; Belton, D.; West, G.

    2014-04-01

    The automatic reconstruction of 3D buildings has been an important research topic during the last years. In this paper, a novel method is proposed to automatically reconstruct the 3D building models from segmented data based on pre-defined formal grammar and rules. Such segmented data can be extracted e.g. from terrestrial or mobile laser scanning devices. Two steps are considered in detail. The first step is to transform the segmented data into 3D shapes, for instance using the DXF (Drawing Exchange Format) format which is a CAD data file format used for data interchange between AutoCAD and other program. Second, we develop a formal grammar to describe the building model structure and integrate the pre-defined grammars into the reconstruction process. Depending on the different segmented data, the selected grammar and rules are applied to drive the reconstruction process in an automatic manner. Compared with other existing approaches, our proposed method allows the model reconstruction directly from 3D shapes and takes the whole building into account.

  2. ARCHAEO-SCAN: Portable 3D shape measurement system for archaeological field work

    NASA Astrophysics Data System (ADS)

    Knopf, George K.; Nelson, Andrew J.

    2004-10-01

    Accurate measurement and thorough documentation of excavated artifacts are the essential tasks of archaeological fieldwork. The on-site recording and long-term preservation of fragile evidence can be improved using 3D spatial data acquisition and computer-aided modeling technologies. Once the artifact is digitized and geometry created in a virtual environment, the scientist can manipulate the pieces in a virtual reality environment to develop a "realistic" reconstruction of the object without physically handling or gluing the fragments. The ARCHAEO-SCAN system is a flexible, affordable 3D coordinate data acquisition and geometric modeling system for acquiring surface and shape information of small to medium sized artifacts and bone fragments. The shape measurement system is being developed to enable the field archaeologist to manually sweep the non-contact sensor head across the relic or artifact surface. A series of unique data acquisition, processing, registration and surface reconstruction algorithms are then used to integrate 3D coordinate information from multiple views into a single reference frame. A novel technique for automatically creating a hexahedral mesh of the recovered fragments is presented. The 3D model acquisition system is designed to operate from a standard laptop with minimal additional hardware and proprietary software support. The captured shape data can be pre-processed and displayed on site, stored digitally on a CD, or transmitted via the Internet to the researcher's home institution.

  3. A multi-thread scheduling method for 3D CT image reconstruction using multi-GPU.

    PubMed

    Zhu, Yining; Zhao, Yunsong; Zhao, Xing

    2012-01-01

    As a whole process, we present a concept that the complete reconstruction of CT image should include the computation part on GPUs and the data storage part on hard disks. From this point of view, we propose a Multi-Thread Scheduling (MTS) method to implement the 3D CT image reconstruction such as using FDK algorithm, to trade off the computing and storage time. In this method we use Multi-Threads to control GPUs and a separate thread to accomplish data storage, so that we make the calculation and data storage simultaneously. In addition, we use the 4-channel texture to maintain symmetrical projection data in CUDA framework, which can reduce the calculation time significantly. Numerical experiment shows that the time for the whole process with our method is almost the same as the data storage time. PMID:22635174

  4. A real-time 3D scanning system for pavement distortion inspection

    NASA Astrophysics Data System (ADS)

    Li, Qingguang; Yao, Ming; Yao, Xun; Xu, Bugao

    2010-01-01

    Pavement distortions, such as rutting and shoving, are the common pavement distress problems that need to be inspected and repaired in a timely manner to ensure ride quality and traffic safety. This paper introduces a real-time, low-cost inspection system devoted to detecting these distress features using high-speed 3D transverse scanning techniques. The detection principle is the dynamic generation and characterization of the 3D pavement profile based on structured light triangulation. To improve the accuracy of the system, a multi-view coplanar scheme is employed in the calibration procedure so that more feature points can be used and distributed across the field of view of the camera. A sub-pixel line extraction method is applied for the laser stripe location, which includes filtering, edge detection and spline interpolation. The pavement transverse profile is then generated from the laser stripe curve and approximated by line segments. The second-order derivatives of the segment endpoints are used to identify the feature points of possible distortions. The system can output the real-time measurements and 3D visualization of rutting and shoving distress in a scanned pavement.

  5. Implementation of 3D prostrate ring-scanning mechanism for NIR diffuse optical imaging phantom validation

    NASA Astrophysics Data System (ADS)

    Yu, Jhao-Ming; Chen, Liang-Yu; Pan, Min-Cheng; Hsu, Ya-Fen; Pan, Min-Chun

    2015-03-01

    Diffuse optical imaging (DOI) providing functional information of tissues has drawn great attention for the last two decades. Near infrared (NIR) DOI systems composed of scanning bench, opt-electrical measurement module, system control, and data processing and image reconstruction schemes are developed for the screening and diagnosis of breast tumors. Mostly, the scanning bench belonging to fixed source-and-detector configuration limits computed image resolution to an extent. To cope with the issue, we propose, design and implement a 3D prostrate ring-scanning equipment for NIR DOI with flexible combinations of illumination and detection, and with the function of radial, circular and vertical movement without hard compression of breast tissue like the imaging system using or incorporating with X-ray mammographic bench. Especially, a rotation-sliding-and-moving mechanism was designed for the guidance of source- and detection-channel movement. Following the previous justification for synthesized image reconstruction, in the paper the validation using varied phantoms is further conducted and 3D image reconstruction for their absorption and scattering coefficients is illustrated through the computation of our in-house coded schemes. The source and detection NIR data are acquired to reconstruct the 3D images through the operation of scanning bench in the movement of vertical, radial and circular directions. Rather than the fixed configuration, the addressed screening/diagnosing equipment has the flexibility for optical-channel expansion with a compromise among construction cost, operation time, and spatial resolution of reconstructed μa and μs' images.

  6. A Tool-Free Calibration Method for Turntable-Based 3D Scanning Systems.

    PubMed

    Pang, Xufang; Lau, Rynson W H; Song, Zhan; Li, Yangyan; He, Shengfeng

    2016-01-01

    Turntable-based 3D scanners are popular but require calibration of the turntable axis. Existing methods for turntable calibration typically make use of specially designed tools, such as a chessboard or criterion sphere, which users must manually install and dismount. In this article, the authors propose an automatic method to calibrate the turntable axis without any calibration tools. Given a scan sequence of the input object, they first recover the initial rotation axis from an automatic registration step. Then they apply an iterative procedure to obtain the optimized turntable axis. This iterative procedure alternates between two steps: refining the initial pose of the input scans and approximating the rotation matrix. The performance of the proposed method was evaluated on a structured light-based scanning system. PMID:25137724

  7. A comprehensive evaluation of the PRESAGE∕optical-CT 3D dosimetry system

    PubMed Central

    Sakhalkar, H. S.; Adamovics, J.; Ibbott, G.; Oldham, M.

    2009-01-01

    This work presents extensive investigations to evaluate the robustness (intradosimeter consistency and temporal stability of response), reproducibility, precision, and accuracy of a relatively new 3D dosimetry system comprising a leuco-dye doped plastic 3D dosimeter (PRESAGE) and a commercial optical-CT scanner (OCTOPUS 5× scanner from MGS Research, Inc). Four identical PRESAGE 3D dosimeters were created such that they were compatible with the Radiologic Physics Center (RPC) head-and-neck (H&N) IMRT credentialing phantom. Each dosimeter was irradiated with a rotationally symmetric arrangement of nine identical small fields (1×3 cm2) impinging on the flat circular face of the dosimeter. A repetitious sequence of three dose levels (4, 2.88, and 1.28 Gy) was delivered. The rotationally symmetric treatment resulted in a dose distribution with high spatial variation in axial planes but only gradual variation with depth along the long axis of the dosimeter. The significance of this treatment was that it facilitated accurate film dosimetry in the axial plane, for independent verification. Also, it enabled rigorous evaluation of robustness, reproducibility and accuracy of response, at the three dose levels. The OCTOPUS 5× commercial scanner was used for dose readout from the dosimeters at daily time intervals. The use of improved optics and acquisition technique yielded substantially improved noise characteristics (reduced to ∼2%) than has been achieved previously. Intradosimeter uniformity of radiochromic response was evaluated by calculating a 3D gamma comparison between each dosimeter and axially rotated copies of the same dosimeter. This convenient technique exploits the rotational symmetry of the distribution. All points in the gamma comparison passed a 2% difference, 1 mm distance-to-agreement criteria indicating excellent intradosimeter uniformity even at low dose levels. Postirradiation, the dosimeters were all found to exhibit a slight increase in opaqueness

  8. A comprehensive evaluation of the PRESAGE/optical-CT 3D dosimetry system.

    PubMed

    Sakhalkar, H S; Adamovics, J; Ibbott, G; Oldham, M

    2009-01-01

    This work presents extensive investigations to evaluate the robustness (intradosimeter consistency and temporal stability of response), reproducibility, precision, and accuracy of a relatively new 3D dosimetry system comprising a leuco-dye doped plastic 3D dosimeter (PRESAGE) and a commercial optical-CT scanner (OCTOPUS 5x scanner from MGS Research, Inc). Four identical PRESAGE 3D dosimeters were created such that they were compatible with the Radiologic Physics Center (RPC) head-and-neck (H&N) IMRT credentialing phantom. Each dosimeter was irradiated with a rotationally symmetric arrangement of nine identical small fields (1 x 3 cm2) impinging on the flat circular face of the dosimeter. A repetitious sequence of three dose levels (4, 2.88, and 1.28 Gy) was delivered. The rotationally symmetric treatment resulted in a dose distribution with high spatial variation in axial planes but only gradual variation with depth along the long axis of the dosimeter. The significance of this treatment was that it facilitated accurate film dosimetry in the axial plane, for independent verification. Also, it enabled rigorous evaluation of robustness, reproducibility and accuracy of response, at the three dose levels. The OCTOPUS 5x commercial scanner was used for dose readout from the dosimeters at daily time intervals. The use of improved optics and acquisition technique yielded substantially improved noise characteristics (reduced to approximately 2%) than has been achieved previously. Intradosimeter uniformity of radiochromic response was evaluated by calculating a 3D gamma comparison between each dosimeter and axially rotated copies of the same dosimeter. This convenient technique exploits the rotational symmetry of the distribution. All points in the gamma comparison passed a 2% difference, 1 mm distance-to-agreement criteria indicating excellent intradosimeter uniformity even at low dose levels. Postirradiation, the dosimeters were all found to exhibit a slight increase in

  9. 3D cardiac motion reconstruction from CT data and tagged MRI.

    PubMed

    Wang, Xiaoxu; Mihalef, Viorel; Qian, Zhen; Voros, Szilard; Metaxas, Dimitris

    2012-01-01

    In this paper we present a novel method for left ventricle (LV) endocardium motion reconstruction using high resolution CT data and tagged MRI. High resolution CT data provide anatomic details on the LV endocardial surface, such as the papillary muscle and trabeculae carneae. Tagged MRI provides better time resolution. The combination of these two imaging techniques can give us better understanding on left ventricle motion. The high resolution CT images are segmented with mean shift method and generate the LV endocardium mesh. The meshless deformable model built with high resolution endocardium surface from CT data fit to the tagged MRI of the same phase. 3D deformation of the myocardium is computed with the Lagrangian dynamics and local Laplacian deformation. The segmented inner surface of left ventricle is compared with the heart inner surface picture and show high agreement. The papillary muscles are attached to the inner surface with roots. The free wall of the left ventricle inner surface is covered with trabeculae carneae. The deformation of the heart wall and the papillary muscle in the first half of the cardiac cycle is presented. The motion reconstruction results are very close to the live heart video. PMID:23366825

  10. 3D Cardiac Motion Reconstruction from CT Data and Tagged MRI

    PubMed Central

    Wang, Xiaoxu; Mihalef, Viorel; Qian, Zhen; Voros, Szilard; Metaxas, Dimitris

    2016-01-01

    In this paper we present a novel method for left ventricle (LV) endocardium motion reconstruction using high resolution CT data and tagged MRI. High resolution CT data provide anatomic details on the LV endocardial surface, such as the papillary muscle and trabeculae carneae. Tagged MRI provides better time resolution. The combination of these two imaging techniques can give us better understanding on left ventricle motion. The high resolution CT images are segmented with mean shift method and generate the LV endocardium mesh. The meshless deformable model built with high resolution endocardium surface from CT data fit to the tagged MRI of the same phase. 3D deformation of the myocardium is computed with the Lagrangian dynamics and local Laplacian deformation. The segmented inner surface of left ventricle is compared with the heart inner surface picture and show high agreement. The papillary muscles are attached to the inner surface with roots. The free wall of the left ventricle inner surface is covered with trabeculae carneae. The deformation of the heart wall and the papillary muscle in the first half of the cardiac cycle is presented. The motion reconstruction results are very close to the live heart video. PMID:23366825

  11. Assessment of angiogenesis in osseointegration of a silica-collagen biomaterial using 3D-nano-CT.

    PubMed

    Alt, Volker; Kögelmaier, Daniela Vera; Lips, Katrin S; Witt, Vera; Pacholke, Sabine; Heiss, Christian; Kampschulte, Marian; Heinemann, Sascha; Hanke, Thomas; Thormann, Ulrich; Schnettler, Reinhard; Langheinrich, Alexander C

    2011-10-01

    Bony integration of biomaterials is a complex process in which angiogenesis plays a crucial role. We evaluated micro- and nano-CT imaging to demonstrate and quantify neovascularization in bony integration of a biomaterial and to give an image based estimation for the needed resolution for imaging angiogenesis in an animal model of femora defect healing. In 8 rats 5mm full-size defects were created at the left femur that was filled with silica-collagen bone substitute material and internally fixed with plate osteosynthesis. After 6 weeks the femora were infused in situ with Microfil, harvested and scanned for micro-CT (9 μm)(3) and nano-CT (3 μm)(3) imaging. Using those 3D images, the newly formed blood vessels in the area of the biomaterial were assessed and the total vascular volume fraction, the volume of the bone substitute material and the volume of the bone defect were quantitatively characterized. Results were complemented by histology. Differences were statistically assessed using (ANOVA). High-resolution nano-CT demonstrated new blood vessel formation surrounding the biomaterial in all animals at capillary level. Immunohistochemistry confirmed the newly formed blood vessels surrounding the bone substitute material. The mean vascular volume fraction (VVF) around the implant was calculated to be 3.01 ± 0.4%. The VVF was inversely correlated with the volume of the bone substitute material (r=0.8) but not with the dimension of the fracture zone (r=0.3). Nano-CT imaging is feasible for quantitative analysis of angiogenesis during bony integration of biomaterials and a promising tool in this context for the future. PMID:21723963

  12. 3D shape measurement for moving scenes using an interlaced scanning colour camera

    NASA Astrophysics Data System (ADS)

    Cao, Senpeng; Cao, Yiping; Lu, Mingteng; Zhang, Qican

    2014-12-01

    A Fourier transform deinterlacing algorithm (FTDA) is proposed to eliminate the blurring and dislocation of the fringe patterns on a moving object captured by an interlaced scanning colour camera in phase measuring profilometry (PMP). Every frame greyscale fringe from three colour channels of every colour fringe is divided into even and odd field fringes respectively, each of which is respectively processed by FTDA. All of the six frames deinterlaced fringes from one colour fringe form two sets of three-step phase-shifted greyscale fringes, with which two 3D shapes corresponding to two different moments are reconstructed by PMP within a frame period. The deinterlaced fringe is identical with the exact frame fringe at the same moment theoretically. The simulation and experiments show its feasibility and validity. The method doubles the time resolution, maintains the precision of the traditional phase measurement profilometry, and has potential applications in the moving and online object’s 3D shape measurements.

  13. An efficient solid modeling system based on a hand-held 3D laser scan device

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Xu, Jun; Xu, Chenxi; Pan, Ming

    2014-12-01

    The hand-held 3D laser scanner sold in the market is appealing for its port and convenient to use, but price is expensive. To develop such a system based cheap devices using the same principles as the commercial systems is impossible. In this paper, a simple hand-held 3D laser scanner is developed based on a volume reconstruction method using cheap devices. Unlike convenient laser scanner to collect point cloud of an object surface, the proposed method only scan few key profile curves on the surface. Planar section curve network can be generated from these profile curves to construct a volume model of the object. The details of design are presented, and illustrated by the example of a complex shaped object.

  14. Analysis of method of 3D shape reconstruction using scanning deflectometry

    NASA Astrophysics Data System (ADS)

    Novák, Jiří; Novák, Pavel; Mikš, Antonín.

    2013-04-01

    This work presents a scanning deflectometric approach to solving a 3D surface reconstruction problem, which is based on measurements of a surface gradient of optically smooth surfaces. It is shown that a description of this problem leads to a nonlinear partial differential equation (PDE) of the first order, from which the surface shape can be reconstructed numerically. The method for effective finding of the solution of this differential equation is proposed, which is based on the transform of the problem of PDE solving to the optimization problem. We describe different types of surface description for the shape reconstruction and a numerical simulation of the presented method is performed. The reconstruction process is analyzed by computer simulations and presented on examples. The performed analysis confirms a robustness of the reconstruction method and a good possibility for measurements and reconstruction of the 3D shape of specular surfaces.

  15. Submucosal Hemangioma of the Trachea in an Infant: Diagnosis and Follow-Up with 3D-CT/Bronchoscopy

    PubMed Central

    Choi, Jungwha; Im, Soo Ah; Kim, Jee Young

    2016-01-01

    Introduction: Infantile hemangiomas of the airway are diagnosed at bronchoscopy as part of the investigation of stridor or other respiratory symptoms. Here, we present three-dimensional computed tomography (3D-CT)/bronchoscopy findings of submucosal subglottic hemangioma missed at bronchoscopy. Case Presentation: We report on the clinical usefulness of 3D-CT/bronchoscopy as the primary diagnostic tool and follow-up method in the evaluation of suspected airway infantile hemangiomas, especially when the hemangioma is the submucosal type. Conclusions: 3D-CT/bronchoscopy will reduce the need for invasive laryngoscopic studies and help to diagnose submucosal hemangiomas undetected on laryngoscope. Additionally, 3D-CT/bronchoscopy will help evaluating the extent of the lesion, degree of airway narrowing, and treatment response. PMID:26848371

  16. The effect of spatial micro-CT image resolution and surface complexity on the morphological 3D analysis of open porous structures

    SciTech Connect

    Pyka, Grzegorz; Kerckhofs, Greet

    2014-01-15

    In material science microfocus X-ray computed tomography (micro-CT) is one of the most popular non-destructive techniques to visualise and quantify the internal structure of materials in 3D. Despite constant system improvements, state-of-the-art micro-CT images can still hold several artefacts typical for X-ray CT imaging that hinder further image-based processing, structural and quantitative analysis. For example spatial resolution is crucial for an appropriate characterisation as the voxel size essentially influences the partial volume effect. However, defining the adequate image resolution is not a trivial aspect and understanding the correlation between scan parameters like voxel size and the structural properties is crucial for comprehensive material characterisation using micro-CT. Therefore, the objective of this study was to evaluate the influence of the spatial image resolution on the micro-CT based morphological analysis of three-dimensional (3D) open porous structures with a high surface complexity. In particular the correlation between the local surface properties and the accuracy of the micro-CT-based macro-morphology of 3D open porous Ti6Al4V structures produced by selective laser melting (SLM) was targeted and revealed for rough surfaces a strong dependence of the resulting structure characteristics on the scan resolution. Reducing the surface complexity by chemical etching decreased the sensitivity of the overall morphological analysis to the spatial image resolution and increased the detection limit. This study showed that scan settings and image processing parameters need to be customized to the material properties, morphological parameters under investigation and the desired final characteristics (in relation to the intended functional use). Customization of the scan resolution can increase the reliability of the micro-CT based analysis and at the same time reduce its operating costs. - Highlights: • We examine influence of the image resolution

  17. 3D camera assisted fully automated calibration of scanning laser Doppler vibrometers

    NASA Astrophysics Data System (ADS)

    Sels, Seppe; Ribbens, Bart; Mertens, Luc; Vanlanduit, Steve

    2016-06-01

    Scanning laser Doppler vibrometers (LDV) are used to measure full-field vibration shapes of products and structures. In most commercially available scanning laser Doppler vibrometer systems the user manually draws a grid of measurement locations on a 2D camera image of the product. The determination of the correct physical measurement locations can be a time consuming and diffcult task. In this paper we present a new methodology for product testing and quality control that integrates 3D imaging techniques with vibration measurements. This procedure allows to test prototypes in a shorter period because physical measurements locations will be located automatically. The proposed methodology uses a 3D time-of-flight camera to measure the location and orientation of the test-object. The 3D image of the time-of-flight camera is then matched with the 3D-CAD model of the object in which measurement locations are pre-defined. A time of flight camera operates strictly in the near infrared spectrum. To improve the signal to noise ratio in the time-of-flight measurement, a time-of-flight camera uses a band filter. As a result of this filter, the laser spot of most laser vibrometers is invisible in the time-of-flight image. Therefore a 2D RGB-camera is used to find the laser-spot of the vibrometer. The laser spot is matched to the 3D image obtained by the time-of-flight camera. Next an automatic calibration procedure is used to aim the laser at the (pre)defined locations. Another benefit from this methodology is that it incorporates automatic mapping between a CAD model and the vibration measurements. This mapping can be used to visualize measurements directly on a 3D CAD model. Secondly the orientation of the CAD model is known with respect to the laser beam. This information can be used to find the direction of the measured vibration relatively to the surface of the object. With this direction, the vibration measurements can be compared more precisely with numerical

  18. 3D scanning and imaging for quick documentation of crime and accident scenes

    NASA Astrophysics Data System (ADS)

    Barazzetti, L.; Sala, R.; Scaioni, M.; Cattaneo, C.; Gibelli, D.; Giussani, A.; Poppa, P.; Roncoroni, F.; Vandone, A.

    2012-06-01

    Fast documentation of complex scenes where accidents or crimes occurred is fundamental not to lose information for post-event analyses and lesson learning. Today 3D terrestrial laser scanning and photogrammetry offer instruments capable of achieving this task. The former allows the fast geometric reconstruction of complex scenes through dense point clouds. Different kinds of instruments can be used according to the size of the area to survey and to the required level of details. The latter can be used for both geometric reconstruction and for photo-realistic texturing of laser scans. While photogrammetry better focuses on small details, laser scanning gives out a more comprehensive view of geometry of whole crime/accident scene. Both techniques can be used for recording a scene just after a crime or a disaster occurred, before the area is cleared out to recover regular activities. Visualization of results through an easy-to-use 3D environment is another import issue to offer useful data to investigators. Here two experiences of crime scene documentation are proposed.

  19. Acceleration of EM-Based 3D CT Reconstruction Using FPGA.

    PubMed

    Choi, Young-Kyu; Cong, Jason

    2016-06-01

    Reducing radiation doses is one of the key concerns in computed tomography (CT) based 3D reconstruction. Although iterative methods such as the expectation maximization (EM) algorithm can be used to address this issue, applying this algorithm to practice is difficult due to the long execution time. Our goal is to decrease this long execution time to an order of a few minutes, so that low-dose 3D reconstruction can be performed even in time-critical events. In this paper we introduce a novel parallel scheme that takes advantage of numerous block RAMs on field-programmable gate arrays (FPGAs). Also, an external memory bandwidth reduction strategy is presented to reuse both the sinogram and the voxel intensity. Moreover, a customized processing engine based on the FPGA is presented to increase overall throughput while reducing the logic consumption. Finally, a hardware and software flow is proposed to quickly construct a design for various CT machines. The complete reconstruction system is implemented on an FPGA-based server-class node. Experiments on actual patient data show that a 26.9 × speedup can be achieved over a 16-thread multicore CPU implementation. PMID:26462240

  20. Description of patellar movement by 3D parameters obtained from dynamic CT acquisition

    NASA Astrophysics Data System (ADS)

    de Sá Rebelo, Marina; Moreno, Ramon Alfredo; Gobbi, Riccardo Gomes; Camanho, Gilberto Luis; de Ávila, Luiz Francisco Rodrigues; Demange, Marco Kawamura; Pecora, Jose Ricardo; Gutierrez, Marco Antonio

    2014-03-01

    The patellofemoral joint is critical in the biomechanics of the knee. The patellofemoral instability is one condition that generates pain, functional impairment and often requires surgery as part of orthopedic treatment. The analysis of the patellofemoral dynamics has been performed by several medical image modalities. The clinical parameters assessed are mainly based on 2D measurements, such as the patellar tilt angle and the lateral shift among others. Besides, the acquisition protocols are mostly performed with the leg laid static at fixed angles. The use of helical multi slice CT scanner can allow the capture and display of the joint's movement performed actively by the patient. However, the orthopedic applications of this scanner have not yet been standardized or widespread. In this work we present a method to evaluate the biomechanics of the patellofemoral joint during active contraction using multi slice CT images. This approach can greatly improve the analysis of patellar instability by displaying the physiology during muscle contraction. The movement was evaluated by computing its 3D displacements and rotations from different knee angles. The first processing step registered the images in both angles based on the femuŕs position. The transformation matrix of the patella from the images was then calculated, which provided the rotations and translations performed by the patella from its position in the first image to its position in the second image. Analysis of these parameters for all frames provided real 3D information about the patellar displacement.

  1. 3D Forward and Back-Projection for X-Ray CT Using Separable Footprints

    PubMed Central

    Long, Yong; Fessler, Jeffrey A.; Balter, James M.

    2010-01-01

    Iterative methods for 3D image reconstruction have the potential to improve image quality over conventional filtered back projection (FBP) in X-ray computed tomography (CT). However, the computation burden of 3D cone-beam forward and back-projectors is one of the greatest challenges facing practical adoption of iterative methods for X-ray CT. Moreover, projector accuracy is also important for iterative methods. This paper describes two new separable footprint (SF) projector methods that approximate the voxel footprint functions as 2D separable functions. Because of the separability of these footprint functions, calculating their integrals over a detector cell is greatly simplified and can be implemented efficiently. The SF-TR projector uses trapezoid functions in the transaxial direction and rectangular functions in the axial direction, whereas the SF-TT projector uses trapezoid functions in both directions. Simulations and experiments showed that both SF projector methods are more accurate than the distance-driven (DD) projector, which is a current state-of-the-art method in the field. The SF-TT projector is more accurate than the SF-TR projector for rays associated with large cone angles. The SF-TR projector has similar computation speed with the DD projector and the SF-TT projector is about two times slower. PMID:20529732

  2. 3D segmentation of the true and false lumens on CT aortic dissection images

    NASA Astrophysics Data System (ADS)

    Fetnaci, Nawel; Łubniewski, Paweł; Miguel, Bruno; Lohou, Christophe

    2013-03-01

    Our works are related to aortic dissections which are a medical emergency and can quickly lead to death. In this paper, we want to retrieve in CT images the false and the true lumens which are aortic dissection features. Our aim is to provide a 3D view of the lumens that we can difficultly obtain either by volume rendering or by another visualization tool which only directly gives the outer contour of the aorta; or by other segmentation methods because they mainly directly segment either only the outer contour of the aorta or other connected arteries and organs both. In our work, we need to segment the two lumens separately; this segmentation will allow us to: distinguish them automatically, facilitate the landing of the aortic prosthesis, propose a virtual 3d navigation and do quantitative analysis. We chose to segment these data by using a deformable model based on the fast marching method. In the classical fast marching approach, a speed function is used to control the front propagation of a deforming curve. The speed function is only based on the image gradient. In our CT images, due to the low resolution, with the fast marching the front propagates from a lumen to the other; therefore, the gradient data is insufficient to have accurate segmentation results. In the paper, we have adapted the fast marching method more particularly by modifying the speed function and we succeed in segmenting the two lumens separately.

  3. Diagnostic Capability of Peripapillary Retinal Thickness in Glaucoma Using 3D Volume Scans

    PubMed Central

    Simavli, Huseyin; Que, Christian John; Akduman, Mustafa; Rizzo, Jennifer L.; Tsikata, Edem; de Boer, Johannes F.; Chen, Teresa C.

    2015-01-01

    Purpose To determine the diagnostic capability of spectral domain optical coherence tomography (SD-OCT) peripapillary retinal thickness (RT) measurements from 3-dimensional (3D) volume scans for primary open angle glaucoma (POAG). Design Cross-sectional study. Methods Setting Institutional Study population 156 patients (89 POAG and 67 normal subjects) Observation procedures One eye of each subject was included. SD-OCT peripapillary RT values from 3D volume scans were calculated for four quadrants of three different sized annuli. Peripapillary retinal nerve fiber layer (RNFL) thickness values were also determined. Main outcome measures Area under the receiver operating characteristic curve (AUROC) values, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. Results The top five RT AUROCs for all glaucoma patients and for a subset of early glaucoma patients were for the inferior quadrant of outer circumpapillary annulus of circular grid (OCA) 1 (0.959, 0.939), inferior quadrant of OCA2 (0.945, 0.921), superior quadrant of OCA1 (0.890, 0.811), inferior quadrant of OCA3 (0.887, 0.854), and superior quadrant of OCA2 (0.879, 0.807). Smaller RT annuli OCA1 and OCA2 consistently showed better diagnostic performance than the larger RT annulus OCA3. For both RNFL and RT measurements, best AUROC values were found for inferior RT OCA1 and OCA2, followed by inferior and overall RNFL thickness. Conclusion Peripapillary RT measurements from 3D volume scans showed excellent diagnostic performance for detecting both glaucoma and early glaucoma patients. Peripapillary RT values have the same or better diagnostic capability compared to peripapillary RNFL thickness measurements, while also having fewer algorithm errors. PMID:25498354

  4. Determining the 3-D structure and motion of objects using a scanning laser range sensor

    NASA Technical Reports Server (NTRS)

    Nandhakumar, N.; Smith, Philip W.

    1993-01-01

    In order for the EVAHR robot to autonomously track and grasp objects, its vision system must be able to determine the 3-D structure and motion of an object from a sequence of sensory images. This task is accomplished by the use of a laser radar range sensor which provides dense range maps of the scene. Unfortunately, the currently available laser radar range cameras use a sequential scanning approach which complicates image analysis. Although many algorithms have been developed for recognizing objects from range images, none are suited for use with single beam, scanning, time-of-flight sensors because all previous algorithms assume instantaneous acquisition of the entire image. This assumption is invalid since the EVAHR robot is equipped with a sequential scanning laser range sensor. If an object is moving while being imaged by the device, the apparent structure of the object can be significantly distorted due to the significant non-zero delay time between sampling each image pixel. If an estimate of the motion of the object can be determined, this distortion can be eliminated; but, this leads to the motion-structure paradox - most existing algorithms for 3-D motion estimation use the structure of objects to parameterize their motions. The goal of this research is to design a rigid-body motion recovery technique which overcomes this limitation. The method being developed is an iterative, linear, feature-based approach which uses the non-zero image acquisition time constraint to accurately recover the motion parameters from the distorted structure of the 3-D range maps. Once the motion parameters are determined, the structural distortion in the range images is corrected.

  5. CT cardiac imaging: evolution from 2D to 3D backprojection

    NASA Astrophysics Data System (ADS)

    Tang, Xiangyang; Pan, Tinsu; Sasaki, Kosuke

    2004-04-01

    The state-of-the-art multiple detector-row CT, which usually employs fan beam reconstruction algorithms by approximating a cone beam geometry into a fan beam geometry, has been well recognized as an important modality for cardiac imaging. At present, the multiple detector-row CT is evolving into volumetric CT, in which cone beam reconstruction algorithms are needed to combat cone beam artifacts caused by large cone angle. An ECG-gated cardiac cone beam reconstruction algorithm based upon the so-called semi-CB geometry is implemented in this study. To get the highest temporal resolution, only the projection data corresponding to 180° plus the cone angle are row-wise rebinned into the semi-CB geometry for three-dimensional reconstruction. Data extrapolation is utilized to extend the z-coverage of the ECG-gated cardiac cone beam reconstruction algorithm approaching the edge of a CT detector. A helical body phantom is used to evaluate the ECG-gated cone beam reconstruction algorithm"s z-coverage and capability of suppressing cone beam artifacts. Furthermore, two sets of cardiac data scanned by a multiple detector-row CT scanner at 16 x 1.25 (mm) and normalized pitch 0.275 and 0.3 respectively are used to evaluate the ECG-gated CB reconstruction algorithm"s imaging performance. As a reference, the images reconstructed by a fan beam reconstruction algorithm for multiple detector-row CT are also presented. The qualitative evaluation shows that, the ECG-gated cone beam reconstruction algorithm outperforms its fan beam counterpart from the perspective of cone beam artifact suppression and z-coverage while the temporal resolution is well maintained. Consequently, the scan speed can be increased to reduce the contrast agent amount and injection time, improve the patient comfort and x-ray dose efficiency. Based up on the comparison, it is believed that, with the transition of multiple detector-row CT into volumetric CT, ECG-gated cone beam reconstruction algorithms will

  6. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

    NASA Astrophysics Data System (ADS)

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  7. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy.

    PubMed

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-21

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  8. Determination of 3D location and rotation of lumbar vertebrae in CT images by symmetry-based auto-registration

    NASA Astrophysics Data System (ADS)

    Vrtovec, Tomaž; Likar, Boštjan; Pernuš, Franjo

    2007-03-01

    Quantitative measurement of vertebral rotation is important in surgical planning, analysis of surgical results, and monitoring of the progression of spinal deformities. However, many established and newly developed techniques for measuring axial vertebral rotation do not exploit three-dimensional (3D) information, which may result in virtual axial rotation because of the sagittal and coronal rotation of vertebrae. We propose a novel automatic approach to the measurement of the location and rotation of vertebrae in 3D without prior volume reformation, identification of appropriate cross-sections or aid by statistical models. The vertebra under investigation is encompassed by a mask in the form of an elliptical cylinder in 3D, defined by its center of rotation and the rotation angles. We exploit the natural symmetry of the vertebral body, vertebral column and vertebral canal by dividing the vertebral mask by its mid-axial, mid-sagittal and mid-coronal plane, so that the obtained volume pairs contain symmetrical parts of the observed anatomy. Mirror volume pairs are then simultaneously registered to each other by robust rigid auto-registration, using the weighted sum of absolute differences between the intensities of the corresponding volume pairs as the similarity measure. The method was evaluated on 50 lumbar vertebrae from normal and scoliotic computed tomography (CT) spinal scans, showing relatively large capture ranges and distinctive maxima at the correct locations and rotation angles. The proposed method may aid the measurement of the dimensions of vertebral pedicles, foraminae and canal, and may be a valuable tool for clinical evaluation of the spinal deformities in 3D.

  9. Exploring miniature insect brains using micro-CT scanning techniques.

    PubMed

    Smith, Dylan B; Bernhardt, Galina; Raine, Nigel E; Abel, Richard L; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J

    2016-01-01

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures. PMID:26908205

  10. Exploring miniature insect brains using micro-CT scanning techniques

    PubMed Central

    Smith, Dylan B.; Bernhardt, Galina; Raine, Nigel E.; Abel, Richard L.; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J.

    2016-01-01

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures. PMID:26908205

  11. 3D scanning electron microscopy applied to surface characterization of fluorosed dental enamel.

    PubMed

    Limandri, Silvina; Galván Josa, Víctor; Valentinuzzi, María Cecilia; Chena, María Emilia; Castellano, Gustavo

    2016-05-01

    The enamel surfaces of fluorotic teeth were studied by scanning electron stereomicroscopy. Different whitening treatments were applied to 25 pieces to remove stains caused by fluorosis and their surfaces were characterized by stereomicroscopy in order to obtain functional and amplitude parameters. The topographic features resulting for each treatment were determined through these parameters. The results obtained show that the 3D reconstruction achieved from the SEM stereo pairs is a valuable potential alternative for the surface characterization of this kind of samples. PMID:26930005

  12. Scanning cross-correlator for monitoring uniform 3D ellipsoidal laser beams

    SciTech Connect

    Zelenogorskii, V V; Andrianov, A V; Gacheva, E I; Gelikonov, G V; Mironov, S Yu; Potemkin, A K; Khazanov, E A; Krasilnikov, M; Stephan, F; Mart'yanov, M A; Syresin, E M

    2014-01-31

    The specific features of experimental implementation of a cross-correlator with a scan rate above 1600 cm s{sup -1} and a spatial delay amplitude of more than 15 mm are considered. The possibility of measuring the width of femtosecond pulses propagating in a train 300 μs in duration with a repetition rate of 1 MHz is demonstrated. A time resolution of 300 fs for the maximum time window of 50 ps is attained. The cross-correlator is aimed at testing 3D pulses of a laser driver of an electron photo-injector. (laser applications and other topics in quantum electronics)

  13. 3D laser scanning microscopy of hypervelocity impact features in metal and aerogel targets

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Postberg, F.; Price, M. C.; Trieloff, M.; Li, Y. W.; Srama, R.

    2012-09-01

    We present the results of a study into the mapping of hypervelocity impact features using a Keyence VK-X200 3D laser scanning microscope. The impact features observed are impact craters in a variety of different metal targets (Al, Au and Cu) and impact tracks in aerogel targets, similar to those used in the Stardust mission. Differences in crater morphology between different target materials and impact velocities, as well as differences in track depth and diameter in aerogel, for particles of known constant dimensions, are discussed.

  14. Semi-automatic 3D segmentation of costal cartilage in CT data from Pectus Excavatum patients

    NASA Astrophysics Data System (ADS)

    Barbosa, Daniel; Queirós, Sandro; Rodrigues, Nuno; Correia-Pinto, Jorge; Vilaça, J.

    2015-03-01

    One of the current frontiers in the clinical management of Pectus Excavatum (PE) patients is the prediction of the surgical outcome prior to the intervention. This can be done through computerized simulation of the Nuss procedure, which requires an anatomically correct representation of the costal cartilage. To this end, we take advantage of the costal cartilage tubular structure to detect it through multi-scale vesselness filtering. This information is then used in an interactive 2D initialization procedure which uses anatomical maximum intensity projections of 3D vesselness feature images to efficiently initialize the 3D segmentation process. We identify the cartilage tissue centerlines in these projected 2D images using a livewire approach. We finally refine the 3D cartilage surface through region-based sparse field level-sets. We have tested the proposed algorithm in 6 noncontrast CT datasets from PE patients. A good segmentation performance was found against reference manual contouring, with an average Dice coefficient of 0.75±0.04 and an average mean surface distance of 1.69+/-0.30mm. The proposed method requires roughly 1 minute for the interactive initialization step, which can positively contribute to an extended use of this tool in clinical practice, since current manual delineation of the costal cartilage can take up to an hour.

  15. Automatic 3D pulmonary nodule detection in CT images: A survey.

    PubMed

    Valente, Igor Rafael S; Cortez, Paulo César; Neto, Edson Cavalcanti; Soares, José Marques; de Albuquerque, Victor Hugo C; Tavares, João Manuel R S

    2016-02-01

    This work presents a systematic review of techniques for the 3D automatic detection of pulmonary nodules in computerized-tomography (CT) images. Its main goals are to analyze the latest technology being used for the development of computational diagnostic tools to assist in the acquisition, storage and, mainly, processing and analysis of the biomedical data. Also, this work identifies the progress made, so far, evaluates the challenges to be overcome and provides an analysis of future prospects. As far as the authors know, this is the first time that a review is devoted exclusively to automated 3D techniques for the detection of pulmonary nodules from lung CT images, which makes this work of noteworthy value. The research covered the published works in the Web of Science, PubMed, Science Direct and IEEEXplore up to December 2014. Each work found that referred to automated 3D segmentation of the lungs was individually analyzed to identify its objective, methodology and results. Based on the analysis of the selected works, several studies were seen to be useful for the construction of medical diagnostic aid tools. However, there are certain aspects that still require attention such as increasing algorithm sensitivity, reducing the number of false positives, improving and optimizing the algorithm detection of different kinds of nodules with different sizes and shapes and, finally, the ability to integrate with the Electronic Medical Record Systems and Picture Archiving and Communication Systems. Based on this analysis, we can say that further research is needed to develop current techniques and that new algorithms are needed to overcome the identified drawbacks. PMID:26652979

  16. 3D CT-guided pulsed radiofrequency treatment for trigeminal neuralgia.

    PubMed

    Fang, Luo; Ying, Shen; Tao, Wang; Lan, Meng; Xiaotong, Yu; Nan, Ji

    2014-01-01

    Trigeminal neuralgia (TN) is a pain syndrome characterized by pain in the trigeminal area often accompanied by a brief facial spasm or tic. The purpose of our study was to investigate the efficacy and clinical utility of CT-guided pulsed radiofrequency (PRF) for treatment of TN. Patients who were diagnosed with severe TN between September 2010 and October 2010 at Beijing Tiantan Hospital were included. Pulsed radiofrequency treatment (PRFT) was employed to treat TN. To verify the accurate needle position, a thin-section cranial CT scan was performed by using a multidetector CT scanner. Three-dimensional reconstruction was performed to visualize the location of the needle and the foramen ovale. A total of 20 patients were included in the study. Seven patients (35%) had favorable outcome 1 year after the PRFT. The numeric rating scale in the 7 patients with good outcome was significantly lower than the 13 patients with bad outcome at 1 day, 1 week, and 2 weeks after the treatment. The remaining 13 patients had residual pain 2 weeks after the PRFT and had to receive radiofrequency thermocoagulation (RFTC). In conclusion, the results of our study demonstrate that CT-guided PRFT is not an effective method of pain treatment for idiopathic TN as compared with conventional RFTC. However, CT-guided PRFT is associated with less complication than RFTC. PMID:23433058

  17. Optimization of 3D laser scanning speed by use of combined variable step

    NASA Astrophysics Data System (ADS)

    Garcia-Cruz, X. M.; Sergiyenko, O. Yu.; Tyrsa, Vera; Rivas-Lopez, M.; Hernandez-Balbuena, D.; Rodriguez-Quiñonez, J. C.; Basaca-Preciado, L. C.; Mercorelli, P.

    2014-03-01

    The problem of 3D TVS slow functioning caused by constant small scanning step becomes its solution in the presented research. It can be achieved by combined scanning step application for the fast search of n obstacles in unknown surroundings. Such a problem is of keynote importance in automatic robot navigation. To maintain a reasonable speed robots must detect dangerous obstacles as soon as possible, but all known scanners able to measure distances with sufficient accuracy are unable to do it in real time. So, the related technical task of the scanning with variable speed and precise digital mapping only for selected spatial sectors is under consideration. A wide range of simulations in MATLAB 7.12.0 of several variants of hypothetic scenes with variable n obstacles in each scene (including variation of shapes and sizes) and scanning with incremented angle value (0.6° up to 15°) is provided. The aim of such simulation was to detect which angular values of interval still permit getting the maximal information about obstacles without undesired time losses. Three of such local maximums were obtained in simulations and then rectified by application of neuronal network formalism (Levenberg-Marquradt Algorithm). The obtained results in its turn were applied to MET (Micro-Electro-mechanical Transmission) design for practical realization of variable combined step scanning on an experimental prototype of our previously known laser scanner.

  18. Error Analysis of Terrestrial Laser Scanning Data by Means of Spherical Statistics and 3D Graphs

    PubMed Central

    Cuartero, Aurora; Armesto, Julia; Rodríguez, Pablo G.; Arias, Pedro

    2010-01-01

    This paper presents a complete analysis of the positional errors of terrestrial laser scanning (TLS) data based on spherical statistics and 3D graphs. Spherical statistics are preferred because of the 3D vectorial nature of the spatial error. Error vectors have three metric elements (one module and two angles) that were analyzed by spherical statistics. A study case has been presented and discussed in detail. Errors were calculating using 53 check points (CP) and CP coordinates were measured by a digitizer with submillimetre accuracy. The positional accuracy was analyzed by both the conventional method (modular errors analysis) and the proposed method (angular errors analysis) by 3D graphics and numerical spherical statistics. Two packages in R programming language were performed to obtain graphics automatically. The results indicated that the proposed method is advantageous as it offers a more complete analysis of the positional accuracy, such as angular error component, uniformity of the vector distribution, error isotropy, and error, in addition the modular error component by linear statistics. PMID:22163461

  19. Topographical surveys: Classical method versus 3D laser scanning. Case study - An application in civil engineering

    NASA Astrophysics Data System (ADS)

    Grigoraş, I.-R.; Covăsnianu, A.; Pleşu, G.; Benedict, B.

    2009-04-01

    The paper describes an experiment which took place in Iasi town, Romania, consisted in two different topographical survey techniques applied for one and the same objective placed in a block within the city (western part) - a thermal power station. The purpose was to compare those methods and to determine which one is proper to be used in this domain in terms of fastness, optimization and speed of data processing. First technique applied for our survey was the classical one, with a total station. Using the CAD technique, we obtained a final product (a dwg file) and a list of coordinates (a text file). The second method, which we focused our attention more, was the measurement with a very precise 3D laser scanstation, also very suitable in archeology. The data obtained were processed with special software. Result was a 3D model of the thermal power plant composed of measurable cloud point data. Finally, analyzing the advantages and disadvantages of each method, we came to the conclusion that the 3D laser scanning which we used matches well the application, in this case civil engineering, but the future of accepting and implementing this technique is in the hands of Romanian authorities.

  20. State of the art of 3D scanning systems and inspection of textile surfaces

    NASA Astrophysics Data System (ADS)

    Montilla, M.; Orjuela-Vargas, S. A.; Philips, W.

    2014-02-01

    The rapid development of hardware and software in the digital image processing field has boosted research in computer vision for applications in industry. The development of new electronic devices and the tendency to decrease their prices makes possible new developments that few decades ago were possible only in the imagination. This is the case of 3D imaging technology which permits to detect failures in industrial products by inspecting aspects on their 3D surface. In search of an optimal solution for scanning textiles we present in this paper a review of existing techniques for digitizing 3D surfaces. Topographic details of textiles can be obtained by digitizing surfaces using laser line triangulation, phase shifting optical triangulation, projected-light, stereo-vision systems and silhouette analysis. Although we are focused on methods that have been used in the textile industry, we also consider potential mechanisms used for other applications. We discuss the advantages and disadvantages of the evaluated methods and state a summary of potential implementations for the textile industry.

  1. Three-dimensional image technology in forensic anthropology: Assessing the validity of biological profiles derived from CT-3D images of the skeleton

    NASA Astrophysics Data System (ADS)

    Garcia de Leon Valenzuela, Maria Julia

    This project explores the reliability of building a biological profile for an unknown individual based on three-dimensional (3D) images of the individual's skeleton. 3D imaging technology has been widely researched for medical and engineering applications, and it is increasingly being used as a tool for anthropological inquiry. While the question of whether a biological profile can be derived from 3D images of a skeleton with the same accuracy as achieved when using dry bones has been explored, bigger sample sizes, a standardized scanning protocol and more interobserver error data are needed before 3D methods can become widely and confidently used in forensic anthropology. 3D images of Computed Tomography (CT) scans were obtained from 130 innominate bones from Boston University's skeletal collection (School of Medicine). For each bone, both 3D images and original bones were assessed using the Phenice and Suchey-Brooks methods. Statistical analysis was used to determine the agreement between 3D image assessment versus traditional assessment. A pool of six individuals with varying experience in the field of forensic anthropology scored a subsample (n = 20) to explore interobserver error. While a high agreement was found for age and sex estimation for specimens scored by the author, the interobserver study shows that observers found it difficult to apply standard methods to 3D images. Higher levels of experience did not result in higher agreement between observers, as would be expected. Thus, a need for training in 3D visualization before applying anthropological methods to 3D bones is suggested. Future research should explore interobserver error using a larger sample size in order to test the hypothesis that training in 3D visualization will result in a higher agreement between scores. The need for the development of a standard scanning protocol focusing on the optimization of 3D image resolution is highlighted. Applications for this research include the possibility

  2. Swarm Intelligence Integrated Graph-Cut for Liver Segmentation from 3D-CT Volumes

    PubMed Central

    Eapen, Maya; Korah, Reeba; Geetha, G.

    2015-01-01

    The segmentation of organs in CT volumes is a prerequisite for diagnosis and treatment planning. In this paper, we focus on liver segmentation from contrast-enhanced abdominal CT volumes, a challenging task due to intensity overlapping, blurred edges, large variability in liver shape, and complex background with cluttered features. The algorithm integrates multidiscriminative cues (i.e., prior domain information, intensity model, and regional characteristics of liver in a graph-cut image segmentation framework). The paper proposes a swarm intelligence inspired edge-adaptive weight function for regulating the energy minimization of the traditional graph-cut model. The model is validated both qualitatively (by clinicians and radiologists) and quantitatively on publically available computed tomography (CT) datasets (MICCAI 2007 liver segmentation challenge, 3D-IRCAD). Quantitative evaluation of segmentation results is performed using liver volume calculations and a mean score of 80.8% and 82.5% on MICCAI and IRCAD dataset, respectively, is obtained. The experimental result illustrates the efficiency and effectiveness of the proposed method. PMID:26689833

  3. Validation of bone segmentation and improved 3-D registration using contour coherency in CT data.

    PubMed

    Wang, Liping Ingrid; Greenspan, Michael; Ellis, Randy

    2006-03-01

    A method is presented to validate the segmentation of computed tomography (CT) image sequences, and improve the accuracy and efficiency of the subsequent registration of the three-dimensional surfaces that are reconstructed from the segmented slices. The method compares the shapes of contours extracted from neighborhoods of slices in CT stacks of tibias. The bone is first segmented by an automatic segmentation technique, and the bone contour for each slice is parameterized as a one-dimensional function of normalized arc length versus inscribed angle. These functions are represented as vectors within a K-dimensional space comprising the first K amplitude coefficients of their Fourier Descriptors. The similarity or coherency of neighboring contours is measured by comparing statistical properties of their vector representations within this space. Experimentation has demonstrated this technique to be very effective at identifying low-coherency segmentations. Compared with experienced human operators, in a set of 23 CT stacks (1,633 slices), the method correctly detected 87.5% and 80% of the low-coherency and 97.7% and 95.5% of the high coherency segmentations, respectively from two different automatic segmentation techniques. Removal of the automatically detected low-coherency segmentations also significantly improved the accuracy and time efficiency of the registration of 3-D bone surface models. The registration error was reduced by over 500% (i.e., a factor of 5) and 280%, and the computational performance was improved by 540% and 791% for the two respective segmentation methods. PMID:16524088

  4. 3-D micro surface profilometry employing novel Mirau-based lateral scanning interferometry

    NASA Astrophysics Data System (ADS)

    Chen, Liang-Chia; Le, Manh-Trung; Lin, Yi-Shiuan

    2014-09-01

    An innovative 3-D surface imaging methodology for reconstructing micro surface profiles with a long depth measuring range and a nano-scale resolution was developed using the newly developed Mirau-based lateral scanning interferometry (LSI). The current measuring field of view (FOV) of conventional white light interferometers is limited by microscopic views of the existing interferometric objectives, such as those in Michelson, Mirau or Linnik designs. Moreover, the vertical scanning operation required for acquiring volumetric interferometric data is extremely time-consuming and makes white light vertical scanning interferometry (VSI) infeasible for automatic optical inspection (AOI) of micro 3-D structures. To resolve this, a newly developed white light LSI method based on Mirau’s optical configuration was developed by controlling the tilting angle of the reference mirror in the Mirau interferometric objective. With the proposed optical configuration, the surface is inspected at a tilting angle with respect to the maximum coherence plane of the interferometric system along its lateral scanning direction when the objective lies perpendicular to the tested surface. In addition, a system calibration method was developed to establish an accurate mathematical mapping model between the object depth and the lateral axis. To evaluate the feasibility of the methodology, a calibrated step height was measured for evaluating the accuracy and repeatability. Some industrial samples, such as photon spacers and other microstructures fabricated by nano-imprinting processes, were measured to verify the actual performance on real components. It was found that the measurement repeatability was controlled less than 60 nm within one standard deviation for a maximum measurable depth of 27.21 µm.

  5. 3D change detection at street level using mobile laser scanning point clouds and terrestrial images

    NASA Astrophysics Data System (ADS)

    Qin, Rongjun; Gruen, Armin

    2014-04-01

    Automatic change detection and geo-database updating in the urban environment are difficult tasks. There has been much research on detecting changes with satellite and aerial images, but studies have rarely been performed at the street level, which is complex in its 3D geometry. Contemporary geo-databases include 3D street-level objects, which demand frequent data updating. Terrestrial images provides rich texture information for change detection, but the change detection with terrestrial images from different epochs sometimes faces problems with illumination changes, perspective distortions and unreliable 3D geometry caused by the lack of performance of automatic image matchers, while mobile laser scanning (MLS) data acquired from different epochs provides accurate 3D geometry for change detection, but is very expensive for periodical acquisition. This paper proposes a new method for change detection at street level by using combination of MLS point clouds and terrestrial images: the accurate but expensive MLS data acquired from an early epoch serves as the reference, and terrestrial images or photogrammetric images captured from an image-based mobile mapping system (MMS) at a later epoch are used to detect the geometrical changes between different epochs. The method will automatically mark the possible changes in each view, which provides a cost-efficient method for frequent data updating. The methodology is divided into several steps. In the first step, the point clouds are recorded by the MLS system and processed, with data cleaned and classified by semi-automatic means. In the second step, terrestrial images or mobile mapping images at a later epoch are taken and registered to the point cloud, and then point clouds are projected on each image by a weighted window based z-buffering method for view dependent 2D triangulation. In the next step, stereo pairs of the terrestrial images are rectified and re-projected between each other to check the geometrical

  6. Automated kidney detection for 3D ultrasound using scan line searching

    NASA Astrophysics Data System (ADS)

    Noll, Matthias; Nadolny, Anne; Wesarg, Stefan

    2016-04-01

    Ultrasound (U/S) is a fast and non-expensive imaging modality that is used for the examination of various anatomical structures, e.g. the kidneys. One important task for automatic organ tracking or computer-aided diagnosis is the identification of the organ region. During this process the exact information about the transducer location and orientation is usually unavailable. This renders the implementation of such automatic methods exceedingly challenging. In this work we like to introduce a new automatic method for the detection of the kidney in 3D U/S images. This novel technique analyses the U/S image data along virtual scan lines. Here, characteristic texture changes when entering and leaving the symmetric tissue regions of the renal cortex are searched for. A subsequent feature accumulation along a second scan direction produces a 2D heat map of renal cortex candidates, from which the kidney location is extracted in two steps. First, the strongest candidate as well as its counterpart are extracted by heat map intensity ranking and renal cortex size analysis. This process exploits the heat map gap caused by the renal pelvis region. Substituting the renal pelvis detection with this combined cortex tissue feature increases the detection robustness. In contrast to model based methods that generate characteristic pattern matches, our method is simpler and therefore faster. An evaluation performed on 61 3D U/S data sets showed, that in 55 cases showing none or minor shadowing the kidney location could be correctly identified.

  7. 3D surface scan of biological samples with a Push-broom Imaging Spectrometer

    NASA Astrophysics Data System (ADS)

    Yao, Haibo; Kincaid, Russell; Hruska, Zuzana; Brown, Robert L.; Bhatnagar, Deepak; Cleveland, Thomas E.

    2013-08-01

    The food industry is always on the lookout for sensing technologies for rapid and nondestructive inspection of food products. Hyperspectral imaging technology integrates both imaging and spectroscopy into unique imaging sensors. Its application for food safety and quality inspection has made significant progress in recent years. Specifically, hyperspectral imaging has shown its potential for surface contamination detection in many food related applications. Most existing hyperspectral imaging systems use pushbroom scanning which is generally used for flat surface inspection. In some applications it is desirable to be able to acquire hyperspectral images on circular objects such as corn ears, apples, and cucumbers. Past research describes inspection systems that examine all surfaces of individual objects. Most of these systems did not employ hyperspectral imaging. These systems typically utilized a roller to rotate an object, such as an apple. During apple rotation, the camera took multiple images in order to cover the complete surface of the apple. The acquired image data lacked the spectral component present in a hyperspectral image. This paper discusses the development of a hyperspectral imaging system for a 3-D surface scan of biological samples. The new instrument is based on a pushbroom hyperspectral line scanner using a rotational stage to turn the sample. The system is suitable for whole surface hyperspectral imaging of circular objects. In addition to its value to the food industry, the system could be useful for other applications involving 3-D surface inspection.

  8. Accuracy of 3D volumetric image registration based on CT, MR and PET/CT phantom experiments.

    PubMed

    Li, Guang; Xie, Huchen; Ning, Holly; Citrin, Deborah; Capala, Jacek; Maass-Moreno, Roberto; Guion, Peter; Arora, Barbara; Coleman, Norman; Camphausen, Kevin; Miller, Robert W

    2008-01-01

    Registration is critical for image-based treatment planning and image-guided treatment delivery. Although automatic registration is available, manual, visual-based image fusion using three orthogonal planar views (3P) is always employed clinically to verify and adjust an automatic registration result. However, the 3P fusion can be time consuming, observer dependent, as well as prone to errors, owing to the incomplete 3-dimensional (3D) volumetric image representations. It is also limited to single-pixel precision (the screen resolution). The 3D volumetric image registration (3DVIR) technique was developed to overcome these shortcomings. This technique introduces a 4th dimension in the registration criteria beyond the image volume, offering both visual and quantitative correlation of corresponding anatomic landmarks within the two registration images, facilitating a volumetric image alignment, and minimizing potential registration errors. The 3DVIR combines image classification in real-time to select and visualize a reliable anatomic landmark, rather than using all voxels for alignment. To determine the detection limit of the visual and quantitative 3DVIR criteria, slightly misaligned images were simulated and presented to eight clinical personnel for interpretation. Both of the criteria produce a detection limit of 0.1 mm and 0.1 degree. To determine the accuracy of the 3DVIR method, three imaging modalities (CT, MR and PET/CT) were used to acquire multiple phantom images with known spatial shifts. Lateral shifts were applied to these phantoms with displacement intervals of 5.0+/-0.1 mm. The accuracy of the 3DVIR technique was determined by comparing the image shifts determined through registration to the physical shifts made experimentally. The registration accuracy, together with precision, was found to be: 0.02+/-0.09 mm for CT/CT images, 0.03+/-0.07 mm for MR/MR images, and 0.03+/-0.35 mm for PET/CT images. This accuracy is consistent with the detection limit

  9. Measuring Fracture Properties of Meteorites: 3D Scans and Disruption Experiments.

    NASA Astrophysics Data System (ADS)

    Cotto-Figueroa, Desireé; Asphaug, Erik; Morris, Melissa A.; Garvie, Laurence

    2014-11-01

    The Arizona State University (ASU) Center for Meteorite Studies (CMS) houses over 30,000 specimens that represent almost every known meteorite type. A number of these are available for fragmentation experiments in small samples, but in most cases non-destructive experiments are desired in order to determine the fundamental mechanical properties of meteorites, and by extension, the Near-Earth Asteroids (NEAs) and other planetary bodies they derive from. We present results from an ongoing suite of measurements and experiments, featuring automated 3D topographic scans of a comprehensive suite of meteorites in the CMS collection, basic mechanical studies, and culminating in catastrophic fragmentation of four representative meteorites: Tamdakht (H5), Allende (CV3), Northwest Africa 869 (L3-6) and Chelyabinsk (LL5). Results will include high-resolution 3D color-shape models of meteorites, including specimens such as the 349g oriented and fusion crusted Martian (shergottite) Tissint, and the delicately fusion crusted and oriented 131g Whetstone Mountains (H5) ordinary chondrite. The 3D color-shape models will allow us to obtain basic physical properties (such as volume to derive density) and to derive fractal dimensions of fractured surfaces. Fractal dimension is closely related to the internal structural heterogeneity and fragmentation of the material, to macroscopic optical properties, and to rubble friction and cohesion. Freshly fractured surfaces of fragments that will result from catastrophic hypervelocity impact experiments will be subsequently scanned and analyzed in order to determine whether fractal dimension is preserved or if it changes with surface maturation.

  10. Combining supine MRI and 3D optical scanning for improved surgical planning of breast conserving surgeries

    NASA Astrophysics Data System (ADS)

    Pallone, Matthew J.; Poplack, Steven P.; Barth, Richard J., Jr.; Paulsen, Keith D.

    2012-02-01

    Image-guided wire localization is the current standard of care for the excision of non-palpable carcinomas during breast conserving surgeries (BCS). The efficacy of this technique depends upon the accuracy of wire placement, maintenance of the fixed wire position (despite patient movement), and the surgeon's understanding of the spatial relationship between the wire and tumor. Notably, breast shape can vary significantly between the imaging and surgical positions. Despite this method of localization, re-excision is needed in approximately 30% of patients due to the proximity of cancer to the specimen margins. These limitations make wire localization an inefficient and imprecise procedure. Alternatively, we investigate a method of image registration and finite element (FE) deformation which correlates preoperative supine MRIs with 3D optical scans of the breast surface. MRI of the breast can accurately define the extents of very small cancers. Furthermore, supine breast MR reduces the amount of tissue deformation between the imaging and surgical positions. At the time of surgery, the surface contour of the breast may be imaged using a handheld 3D laser scanner. With the MR images segmented by tissue type, the two scans are approximately registered using fiducial markers present in both acquisitions. The segmented MRI breast volume is then deformed to match the optical surface using a FE mechanical model of breast tissue. The resulting images provide the surgeon with 3D views and measurements of the tumor shape, volume, and position within the breast as it appears during surgery which may improve surgical guidance and obviate the need for wire localization.

  11. 3-D x-ray mirror metrology with a vertical scanning long trace profiler

    SciTech Connect

    Takacs, P.Z.; Li, H.; Li, X.; Grindel, M.W.

    1996-09-01

    The long trace profiler (LTP) was originally developed at Brookhaven National Laboratory for the specific purpose of measuring the surface figure of large cylindrical mirrors used at grazing incidence in synchrotron radiation (SR) beamlines. In its original configuration, it could measure only along one line down the center of the cylinder. A single linear profile is often sufficient to gauge the quality of the optical surface on these kinds of mirrors. For some applications it is necessary to measure the topography of the entire surface, not just along one line but over a grid that covers the entire surface area. We have modified a standard LTP to enable measurement of the complete surface of Wolter telescope optics in a vertical configuration. The vertical scanning LTP (VSLTP) is capable of producing a complete 3-D map of the surface topography errors relative to the ideal desired surface on complete segments of paraboloids and hyperboloids. The instrument uses a penta prism assembly to scan the probe beam in the longitudinal direction parallel to the mirror symmetry axis and uses a precision rotary stage to provide scans in the azimuthal direction. A Risley prism pair and a dove prism are used to orient the probe beam in the proper direction for the azimuthal scans. The repeatability of the prototype instrument is better than 20 nm over trace lengths of 35 mm with a slope measurement accuracy of about 1 microradian. {copyright} {ital 1996 American Institute of Physics.}

  12. Automated segmentation of mesothelioma volume on CT scan

    NASA Astrophysics Data System (ADS)

    Zhao, Binsheng; Schwartz, Lawrence; Flores, Raja; Liu, Fan; Kijewski, Peter; Krug, Lee; Rusch, Valerie

    2005-04-01

    In mesothelioma, response is usually assessed by computed tomography (CT). In current clinical practice the Response Evaluation Criteria in Solid Tumors (RECIST) or WHO, i.e., the uni-dimensional or the bi-dimensional measurements, is applied to the assessment of therapy response. However, the shape of the mesothelioma volume is very irregular and its longest dimension is almost never in the axial plane. Furthermore, the sections and the sites where radiologists measure the tumor are rather subjective, resulting in poor reproducibility of tumor size measurements. We are developing an objective three-dimensional (3D) computer algorithm to automatically identify and quantify tumor volumes that are associated with malignant pleural mesothelioma to assess therapy response. The algorithm first extracts the lung pleural surface from the volumetric CT images by interpolating the chest ribs over a number of adjacent slices and then forming a volume that includes the thorax. This volume allows a separation of mesothelioma from the chest wall. Subsequently, the structures inside the extracted pleural lung surface, including the mediastinal area, lung parenchyma, and pleural mesothelioma, can be identified using a multiple thresholding technique and morphological operations. Preliminary results have shown the potential of utilizing this algorithm to automatically detect and quantify tumor volumes on CT scans and thus to assess therapy response for malignant pleural mesothelioma.

  13. Image Quality and Radiation Dose of CT Coronary Angiography with Automatic Tube Current Modulation and Strong Adaptive Iterative Dose Reduction Three-Dimensional (AIDR3D)

    PubMed Central

    Shen, Hesong; Dai, Guochao; Luo, Mingyue; Duan, Chaijie; Cai, Wenli; Liang, Dan; Wang, Xinhua; Zhu, Dongyun; Li, Wenru; Qiu, Jianping

    2015-01-01

    Purpose To investigate image quality and radiation dose of CT coronary angiography (CTCA) scanned using automatic tube current modulation (ATCM) and reconstructed by strong adaptive iterative dose reduction three-dimensional (AIDR3D). Methods Eighty-four consecutive CTCA patients were collected for the study. All patients were scanned using ATCM and reconstructed with strong AIDR3D, standard AIDR3D and filtered back-projection (FBP) respectively. Two radiologists who were blinded to the patients' clinical data and reconstruction methods evaluated image quality. Quantitative image quality evaluation included image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). To evaluate image quality qualitatively, coronary artery is classified into 15 segments based on the modified guidelines of the American Heart Association. Qualitative image quality was evaluated using a 4-point scale. Radiation dose was calculated based on dose-length product. Results Compared with standard AIDR3D, strong AIDR3D had lower image noise, higher SNR and CNR, their differences were all statistically significant (P<0.05); compared with FBP, strong AIDR3D decreased image noise by 46.1%, increased SNR by 84.7%, and improved CNR by 82.2%, their differences were all statistically significant (P<0.05 or 0.001). Segments with diagnostic image quality for strong AIDR3D were 336 (100.0%), 486 (96.4%), and 394 (93.8%) in proximal, middle, and distal part respectively; whereas those for standard AIDR3D were 332 (98.8%), 472 (93.7%), 378 (90.0%), respectively; those for FBP were 217 (64.6%), 173 (34.3%), 114 (27.1%), respectively; total segments with diagnostic image quality in strong AIDR3D (1216, 96.5%) were higher than those of standard AIDR3D (1182, 93.8%) and FBP (504, 40.0%); the differences between strong AIDR3D and standard AIDR3D, strong AIDR3D and FBP were all statistically significant (P<0.05 or 0.001). The mean effective radiation dose was (2.55±1.21) mSv. Conclusion

  14. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from a series of horizontal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  15. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. These views depict vertical slices from side to middle of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  16. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the specimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view is made from three orthogonal slices. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: Los Alamos National Laboratory and the University of Colorado at Boulder).

  17. CT Scans of Soil Specimen Processed in Space

    NASA Technical Reports Server (NTRS)

    1998-01-01

    CT scans of the spcimens on STS-79 reveal internal cone-shaped features and radial patterns not seen in specimens processed on the ground. The lighter areas are the densest in these images. CT scans produced richly detailed images allowing scientists to build 3D models of the interior of the specimens that can be compared with microscopic examination of thin slices. This view depict horizontal slices from top to bottom of a flight specimen. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: Los Alamos National Laboratory and the University of Colorado at Boulder.

  18. 3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

    NASA Astrophysics Data System (ADS)

    Späth, Florian; Behrendt, Andreas; Muppa, Shravan Kumar; Metzendorf, Simon; Riede, Andrea; Wulfmeyer, Volker

    2016-04-01

    High-resolution three-dimensional (3-D) water vapor data of the atmospheric boundary layer (ABL) are required to improve our understanding of land-atmosphere exchange processes. For this purpose, the scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) was developed as well as new analysis tools and visualization methods. The instrument determines 3-D fields of the atmospheric water vapor number density with a temporal resolution of a few seconds and a spatial resolution of up to a few tens of meters. We present three case studies from two field campaigns. In spring 2013, the UHOH DIAL was operated within the scope of the HD(CP)2 Observational Prototype Experiment (HOPE) in western Germany. HD(CP)2 stands for High Definition of Clouds and Precipitation for advancing Climate Prediction and is a German research initiative. Range-height indicator (RHI) scans of the UHOH DIAL show the water vapor heterogeneity within a range of a few kilometers up to an altitude of 2 km and its impact on the formation of clouds at the top of the ABL. The uncertainty of the measured data was assessed for the first time by extending a technique to scanning data, which was formerly applied to vertical time series. Typically, the accuracy of the DIAL measurements is between 0.5 and 0.8 g m-3 (or < 6 %) within the ABL even during daytime. This allows for performing a RHI scan from the surface to an elevation angle of 90° within 10 min. In summer 2014, the UHOH DIAL participated in the Surface Atmosphere Boundary Layer Exchange (SABLE) campaign in southwestern Germany. Conical volume scans were made which reveal multiple water vapor layers in three dimensions. Differences in their heights in different directions can be attributed to different surface elevation. With low-elevation scans in the surface layer, the humidity profiles and gradients can be related to different land cover such as maize, grassland, and forest as well as different surface layer

  19. Imaging knee position using MRI, RSA/CT and 3D digitisation.

    PubMed

    McPherson, A; Kärrholm, J; Pinskerova, V; Sosna, A; Martelli, S

    2005-02-01

    The purpose of this study was to compare 3 methods of imaging knee position. Three fresh cadaver knees were imaged at 6 flexion angles between 0 degrees and 120 degrees by MRI, a combination of RSA and CT and 3D digitisation (in two knees). Virtual models of all 42 positions were created using suitable computer software. Each virtual model was aligned to a newly defined anatomically based Cartesian coordinate system. The angular rotations around the 3 coordinate system axes were calculated directly from the aligned virtual models using rigid body kinematics and found to be equally accurate for the 3 methods. The 3 rotations in each knee could be depicted using anatomy-based diagrams for all 3 methods. We conclude that the 3 methods of data acquisition are equally and adequately accurate in vitro. MRI may be the most useful in vivo. PMID:15598452

  20. Use of 3D reconstruction of emergency and postoperative craniocerebral CT images to explore craniocerebral trauma mechanism.

    PubMed

    Li, Zhengdong; Zou, Donghua; Zhang, Jianhua; Shao, Yu; Huang, Ping; Chen, Yijiu

    2015-10-01

    We report a craniocerebral trauma case in which a man sustained severe skull fractures and cerebral contusions and it demanded elucidating the injury mechanism of being formed by strike or tumble. However, the initial features of skull fractures were mostly lost when the forensic pathologists involved in the case 5 months later because of injury healing and craniocerebral surgery. Therefore, we aimed to reconstruct the original skull fracture features by utilizing the digital reconstruction technologies in terms of CT (computed tomography) scanning, 3D (3-dimentional) reconstruction, and virtual surgical tools. The original fracture skull was assembled by using Mimics 13.0 based on the CT slices of postoperative head and the removed craniotomy skull flaps, which revealed fracture features of focal and overall skull deformation. Based on the assembly skull model and the contrecoup cerebral contusions, we conclude that the man suffered a tumble after being drunk and the serious craniocerebral trauma occurred. The case demonstrated that the digital reconstruction technologies can serve as effective approaches for forensic investigation in case of survived craniocerebral trauma patients without direct evidences interpreting the original trauma patterns, which could potentially be helpful in exploring the injury mechanisms. PMID:26232886

  1. CT and MRI Assessment and Characterization Using Segmentation and 3D Modeling Techniques: Applications to Muscle, Bone and Brain

    PubMed Central

    Helgason, Thordur; Ramon, Ceon; jr, Halldór Jónsson; Carraro, Ugo

    2014-01-01

    This paper reviews the novel use of CT and MRI data and image processing tools to segment and reconstruct tissue images in 3D to determine characteristics of muscle, bone and brain. This to study and simulate the structural changes occurring in healthy and pathological conditions as well as in response to clinical treatments. Here we report the application of this methodology to evaluate and quantify: 1. progression of atrophy in human muscle subsequent to permanent lower motor neuron (LMN) denervation, 2. muscle recovery as induced by functional electrical stimulation (FES), 3. bone quality in patients undergoing total hip replacement and 4. to model the electrical activity of the brain. Study 1: CT data and segmentation techniques were used to quantify changes in muscle density and composition by associating the Hounsfield unit values of muscle, adipose and fibrous connective tissue with different colors. This method was employed to monitor patients who have permanent muscle LMN denervation in the lower extremities under two different conditions: permanent LMN denervated not electrically stimulated and stimulated. Study 2: CT data and segmentation techniques were employed, however, in this work we assessed bone and muscle conditions in the pre-operative CT scans of patients scheduled to undergo total hip replacement. In this work, the overall anatomical structure, the bone mineral density (BMD) and compactness of quadriceps muscles and proximal femoral was computed to provide a more complete view for surgeons when deciding which implant technology to use. Further, a Finite element analysis provided a map of the strains around the proximal femur socket when solicited by typical stresses caused by an implant press fitting. Study 3 describes a method to model the electrical behavior of human brain using segmented MR images. The aim of the work is to use these models to predict the electrical activity of the human brain under normal and pathological conditions by

  2. Radiation dose reduction for coronary artery calcium scoring at 320-detector CT with adaptive iterative dose reduction 3D.

    PubMed

    Tatsugami, Fuminari; Higaki, Toru; Fukumoto, Wataru; Kaichi, Yoko; Fujioka, Chikako; Kiguchi, Masao; Yamamoto, Hideya; Kihara, Yasuki; Awai, Kazuo

    2015-06-01

    To assess the possibility of reducing the radiation dose for coronary artery calcium (CAC) scoring by using adaptive iterative dose reduction 3D (AIDR 3D) on a 320-detector CT scanner. Fifty-four patients underwent routine- and low-dose CT for CAC scoring. Low-dose CT was performed at one-third of the tube current used for routine-dose CT. Routine-dose CT was reconstructed with filtered back projection (FBP) and low-dose CT was reconstructed with AIDR 3D. We compared the calculated Agatston-, volume-, and mass scores of these images. The overall percentage difference in the Agatston-, volume-, and mass scores between routine- and low-dose CT studies was 15.9, 11.6, and 12.6%, respectively. There were no significant differences in the routine- and low-dose CT studies irrespective of the scoring algorithms applied. The CAC measurements of both imaging modalities were highly correlated with respect to the Agatston- (r = 0.996), volume- (r = 0.996), and mass score (r = 0.997; p < 0.001, all); the Bland-Altman limits of agreement scores were -37.4 to 51.4, -31.2 to 36.4 and -30.3 to 40.9%, respectively, suggesting that AIDR 3D was a good alternative for FBP. The mean effective radiation dose for routine- and low-dose CT was 2.2 and 0.7 mSv, respectively. The use of AIDR 3D made it possible to reduce the radiation dose by 67% for CAC scoring without impairing the quantification of coronary calcification. PMID:25754302

  3. 3D Alternating Direction TV-Based Cone-Beam CT Reconstruction with Efficient GPU Implementation

    PubMed Central

    Cai, Ailong; Zhang, Hanming; Li, Lei; Xi, Xiaoqi; Guan, Min; Li, Jianxin

    2014-01-01

    Iterative image reconstruction (IIR) with sparsity-exploiting methods, such as total variation (TV) minimization, claims potentially large reductions in sampling requirements. However, the computation complexity becomes a heavy burden, especially in 3D reconstruction situations. In order to improve the performance for iterative reconstruction, an efficient IIR algorithm for cone-beam computed tomography (CBCT) with GPU implementation has been proposed in this paper. In the first place, an algorithm based on alternating direction total variation using local linearization and proximity technique is proposed for CBCT reconstruction. The applied proximal technique avoids the horrible pseudoinverse computation of big matrix which makes the proposed algorithm applicable and efficient for CBCT imaging. The iteration for this algorithm is simple but convergent. The simulation and real CT data reconstruction results indicate that the proposed algorithm is both fast and accurate. The GPU implementation shows an excellent acceleration ratio of more than 100 compared with CPU computation without losing numerical accuracy. The runtime for the new 3D algorithm is about 6.8 seconds per loop with the image size of 256 × 256 × 256 and 36 projections of the size of 512 × 512. PMID:25045400

  4. Automated 2D-3D registration of a radiograph and a cone beam CT using line-segment enhancement

    SciTech Connect

    Munbodh, Reshma; Jaffray, David A.; Moseley, Douglas J.; Chen Zhe; Knisely, Jonathan P.S.; Cathier, Pascal; Duncan, James S.

    2006-05-15

    The objective of this study was to develop a fully automated two-dimensional (2D)-three-dimensional (3D) registration framework to quantify setup deviations in prostate radiation therapy from cone beam CT (CBCT) data and a single AP radiograph. A kilovoltage CBCT image and kilovoltage AP radiograph of an anthropomorphic phantom of the pelvis were acquired at 14 accurately known positions. The shifts in the phantom position were subsequently estimated by registering digitally reconstructed radiographs (DRRs) from the 3D CBCT scan to the AP radiographs through the correlation of enhanced linear image features mainly representing bony ridges. Linear features were enhanced by filtering the images with ''sticks,'' short line segments which are varied in orientation to achieve the maximum projection value at every pixel in the image. The mean (and standard deviations) of the absolute errors in estimating translations along the three orthogonal axes in millimeters were 0.134 (0.096) AP(out-of-plane), 0.021 (0.023) ML and 0.020 (0.020) SI. The corresponding errors for rotations in degrees were 0.011 (0.009) AP, 0.029 (0.016) ML (out-of-plane), and 0.030 (0.028) SI (out-of-plane). Preliminary results with megavoltage patient data have also been reported. The results suggest that it may be possible to enhance anatomic features that are common to DRRs from a CBCT image and a single AP radiography of the pelvis for use in a completely automated and accurate 2D-3D registration framework for setup verification in prostate radiotherapy. This technique is theoretically applicable to other rigid bony structures such as the cranial vault or skull base and piecewise rigid structures such as the spine.

  5. 3D In Vivo Dosimetry Using Megavoltage Cone-Beam CT and EPID Dosimetry

    SciTech Connect

    Elmpt, Wouter van Nijsten, Sebastiaan; Petit, Steven; Mijnheer, Ben; Lambin, Philippe; Dekker, Andre

    2009-04-01

    Purpose: To develop a method that reconstructs, independently of previous (planning) information, the dose delivered to patients by combining in-room imaging with transit dose measurements during treatment. Methods and Materials: A megavoltage cone-beam CT scan of the patient anatomy was acquired with the patient in treatment position. During treatment, delivered fields were measured behind the patient with an electronic portal imaging device. The dose information in these images was back-projected through the cone-beam CT scan and used for Monte Carlo simulation of the dose distribution inside the cone-beam CT scan. Validation was performed using various phantoms for conformal and IMRT plans. Clinical applicability is shown for a head-and-neck cancer patient treated with IMRT. Results: For single IMRT beams and a seven-field IMRT step-and-shoot plan, the dose distribution was reconstructed within 3%/3mm compared with the measured or planned dose. A three-dimensional conformal plan, verified using eight point-dose measurements, resulted in a difference of 1.3 {+-} 3.3% (1 SD) compared with the reconstructed dose. For the patient case, planned and reconstructed dose distribution was within 3%/3mm for about 95% of the points within the 20% isodose line. Reconstructed mean dose values, obtained from dose-volume histograms, were within 3% of prescribed values for target volumes and normal tissues. Conclusions: We present a new method that verifies the dose delivered to a patient by combining in-room imaging with the transit dose measured during treatment. This verification procedure opens possibilities for offline adaptive radiotherapy and dose-guided radiotherapy strategies taking into account the dose distribution delivered during treatment sessions.

  6. Tomosynthesis using high speed CT scanning system

    SciTech Connect

    Boyd, D.P.; Rutt, B.K.

    1988-04-05

    In a high-speed CT scanning system in which fan beams of radiation are generated by sweeping an electron beam along a target and collimated X-rays emitted by the target are received by an array of detectors after passing through a patient area between the target and the array of detectors, a method of obtaining a tomograph of a patient is described comprising the steps of sweeping the electron beam along the target, measuring radiation received at detector positions as the electron beam is swept along the target; moving the patient past the collimated X-rays, and combining measurements at the detector positions as correlated in time to positions of the patient and tomosynthesizing the tomograph from data for lines in the desired plane for the positions of the patient.

  7. Fast, high-resolution 3D dosimetry utilizing a novel optical-CT scanner incorporating tertiary telecentric collimation.

    PubMed

    Sakhalkar, H S; Oldham, M

    2008-01-01

    This study introduces a charge coupled device (CCD) area detector based optical-computed tomography (optical-CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of approximately 5 min to acquire a complete three-dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray-light sources, and (iii) high resolution (potentially 50 microm) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS-scanner for the same PRESAGE dosimeters. The OCTOPUS scanner was considered the "gold standard" technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment-planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2-field open beam parallel-opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7-field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose-difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold-standard readout from the OCTOPUS-scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few

  8. Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices.

    PubMed

    Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

    2015-01-01

    In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given. PMID:26703624

  9. The study of craniofacial growth patterns using 3D laser scanning and geometric morphometrics

    NASA Astrophysics Data System (ADS)

    Friess, Martin

    2006-02-01

    Throughout childhood, braincase and face grow at different rates and therefore exhibit variable proportions and positions relative to each other. Our understanding of the direction and magnitude of these growth patterns is crucial for many ergonomic applications and can be improved by advanced 3D morphometrics. The purpose of this study is to investigate this known growth allometry using 3D imaging techniques. The geometry of the head and face of 840 children, aged 2 to 19, was captured with a laser surface scanner and analyzed statistically. From each scan, 18 landmarks were extracted and registered using General Procrustes Analysis (GPA). GPA eliminates unwanted variation due to position, orientation and scale by applying a least-squares superimposition algorithm to individual landmark configurations. This approach provides the necessary normalization for the study of differences in size, shape, and their interaction (allometry). The results show that throughout adolescence, boys and girls follow a different growth trajectory, leading to marked differences not only in size but also in shape, most notably in relative proportions of the braincase. These differences can be observed during early childhood, but become most noticeable after the age of 13 years, when craniofacial growth in girls slows down significantly, whereas growth in boys continues for at least 3 more years.

  10. Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices

    PubMed Central

    Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

    2015-01-01

    In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given. PMID:26703624

  11. Shape Analysis of 3D Head Scan Data for U.S. Respirator Users

    NASA Astrophysics Data System (ADS)

    Zhuang, Ziqing; Slice, DennisE; Benson, Stacey; Lynch, Stephanie; Viscusi, DennisJ

    2010-12-01

    In 2003, the National Institute for Occupational Safety and Health (NIOSH) conducted a head-and-face anthropometric survey of diverse, civilian respirator users. Of the 3,997 subjects measured using traditional anthropometric techniques, surface scans and 26 three-dimensional (3D) landmark locations were collected for 947 subjects. The objective of this study was to report the size and shape variation of the survey participants using the 3D data. Generalized Procrustes Analysis (GPA) was conducted to standardize configurations of landmarks associated with individuals into a common coordinate system. The superimposed coordinates for each individual were used as commensurate variables that describe individual shape and were analyzed using Principal Component Analysis (PCA) to identify population variation. The first four principal components (PC) account for 49% of the total sample variation. The first PC indicates that overall size is an important component of facial variability. The second PC accounts for long and narrow or short and wide faces. Longer narrow orbits versus shorter wider orbits can be described by PC3, and PC4 represents variation in the degree of ortho/prognathism. Geometric Morphometrics provides a detailed and interpretable assessment of morphological variation that may be useful in assessing respirators and devising new test and certification standards.

  12. Fast 3D visualization of endogenous brain signals with high-sensitivity laser scanning photothermal microscopy.

    PubMed

    Miyazaki, Jun; Iida, Tadatsune; Tanaka, Shinji; Hayashi-Takagi, Akiko; Kasai, Haruo; Okabe, Shigeo; Kobayashi, Takayoshi

    2016-05-01

    A fast, high-sensitivity photothermal microscope was developed by implementing a spatially segmented balanced detection scheme into a laser scanning microscope. We confirmed a 4.9 times improvement in signal-to-noise ratio in the spatially segmented balanced detection compared with that of conventional detection. The system demonstrated simultaneous bi-modal photothermal and confocal fluorescence imaging of transgenic mouse brain tissue with a pixel dwell time of 20 μs. The fluorescence image visualized neurons expressing yellow fluorescence proteins, while the photothermal signal detected endogenous chromophores in the mouse brain, allowing 3D visualization of the distribution of various features such as blood cells and fine structures probably due to lipids. This imaging modality was constructed using compact and cost-effective laser diodes, and will thus be widely useful in the life and medical sciences. PMID:27231615

  13. Laser Scanning for 3D Object Characterization: Infrastructure for Exploration and Analysis of Vegetation Signatures

    NASA Astrophysics Data System (ADS)

    Koenig, K.; Höfle, B.

    2012-04-01

    Mapping and characterization of the three-dimensional nature of vegetation is increasingly gaining in importance. Deeper insight is required for e.g. forest management, biodiversity assessment, habitat analysis, precision agriculture, renewable energy production or the analysis of interaction between biosphere and atmosphere. However the potential of 3D vegetation characterization has not been exploited so far and new technologies are needed. Laser scanning has evolved into the state-of-the-art technology for highly accurate 3D data acquisition. By now several studies indicated a high value of 3D vegetation description by using laser data. The laser sensors provide a detailed geometric presentation (geometric information) of scanned objects as well as a full profile of laser energy that was scattered back to the sensor (radiometric information). In order to exploit the full potential of these datasets, profound knowledge on laser scanning technology for data acquisition, geoinformation technology for data analysis and object of interest (e.g. vegetation) for data interpretation have to be joined. A signature database is a collection of signatures of reference vegetation objects acquired under known conditions and sensor parameters and can be used to improve information extraction from unclassified vegetation datasets. Different vegetation elements (leaves, branches, etc.) at different heights above ground with different geometric composition contribute to the overall description (i.e. signature) of the scanned object. The developed tools allow analyzing tree objects according to single features (e.g. echo width and signal amplitude) and to any relation of features and derived statistical values (e.g. ratio of laser point attributes). For example, a single backscatter cross section value does not allow for tree species determination, whereas the average echo width per tree segment can give good estimates. Statistical values and/or distributions (e.g. Gaussian

  14. Fast 3D visualization of endogenous brain signals with high-sensitivity laser scanning photothermal microscopy

    PubMed Central

    Miyazaki, Jun; Iida, Tadatsune; Tanaka, Shinji; Hayashi-Takagi, Akiko; Kasai, Haruo; Okabe, Shigeo; Kobayashi, Takayoshi

    2016-01-01

    A fast, high-sensitivity photothermal microscope was developed by implementing a spatially segmented balanced detection scheme into a laser scanning microscope. We confirmed a 4.9 times improvement in signal-to-noise ratio in the spatially segmented balanced detection compared with that of conventional detection. The system demonstrated simultaneous bi-modal photothermal and confocal fluorescence imaging of transgenic mouse brain tissue with a pixel dwell time of 20 μs. The fluorescence image visualized neurons expressing yellow fluorescence proteins, while the photothermal signal detected endogenous chromophores in the mouse brain, allowing 3D visualization of the distribution of various features such as blood cells and fine structures probably due to lipids. This imaging modality was constructed using compact and cost-effective laser diodes, and will thus be widely useful in the life and medical sciences. PMID:27231615

  15. Four-chamber heart modeling and automatic segmentation for 3D cardiac CT volumes

    NASA Astrophysics Data System (ADS)

    Zheng, Yefeng; Georgescu, Bogdan; Barbu, Adrian; Scheuering, Michael; Comaniciu, Dorin

    2008-03-01

    Multi-chamber heart segmentation is a prerequisite for quantification of the cardiac function. In this paper, we propose an automatic heart chamber segmentation system. There are two closely related tasks to develop such a system: heart modeling and automatic model fitting to an unseen volume. The heart is a complicated non-rigid organ with four chambers and several major vessel trunks attached. A flexible and accurate model is necessary to capture the heart chamber shape at an appropriate level of details. In our four-chamber surface mesh model, the following two factors are considered and traded-off: 1) accuracy in anatomy and 2) easiness for both annotation and automatic detection. Important landmarks such as valves and cusp points on the interventricular septum are explicitly represented in our model. These landmarks can be detected reliably to guide the automatic model fitting process. We also propose two mechanisms, the rotation-axis based and parallel-slice based resampling methods, to establish mesh point correspondence, which is necessary to build a statistical shape model to enforce priori shape constraints in the model fitting procedure. Using this model, we develop an efficient and robust approach for automatic heart chamber segmentation in 3D computed tomography (CT) volumes. Our approach is based on recent advances in learning discriminative object models and we exploit a large database of annotated CT volumes. We formulate the segmentation as a two step learning problem: anatomical structure localization and boundary delineation. A novel algorithm, Marginal Space Learning (MSL), is introduced to solve the 9-dimensional similarity transformation search problem for localizing the heart chambers. After determining the pose of the heart chambers, we estimate the 3D shape through learning-based boundary delineation. Extensive experiments demonstrate the efficiency and robustness of the proposed approach, comparing favorably to the state-of-the-art. This

  16. Permanent 3D laser scanning system for an active landslide in Gresten (Austria)

    NASA Astrophysics Data System (ADS)

    Canli, Ekrem; Höfle, Bernhard; Hämmerle, Martin; Benni, Thiebes; Glade, Thomas

    2015-04-01

    Terrestrial laser scanners (TLS) have widely been used for high spatial resolution data acquisition of topographic features and geomorphic analyses. Existing applications encompass different landslides including rockfall, translational or rotational landslides, debris flow, but also coastal cliff erosion, braided river evolution or river bank erosion. The main advantages of TLS are (a) the high spatial sampling density of XYZ-measurements (e.g. 1 point every 2-3 mm at 10 m distance), particularly in comparison with the low data density monitoring techniques such as GNSS or total stations, (b) the millimeter accuracy and precision of the range measurement to centimeter accuracy of the final DEM, and (c) the highly dense area-wide scanning that enables to look through vegetation and to measure bare ground. One of its main constraints is the temporal resolution of acquired data due to labor costs and time requirements for field campaigns. Thus, repetition measurements are generally performed only episodically. However, for an increased scientific understanding of the processes as well as for early warning purposes, we present a novel permanent 3D monitoring setup to increase the temporal resolution of TLS measurements. This accounts for different potential monitoring deliverables such as volumetric calculations, spatio-temporal movement patterns, predictions and even alerting. This system was installed at the active Salcher landslide in Gresten (Austria) that is situated in the transition zone of the Gresten Klippenbelt (Helvetic) and the Flyschzone (Penninic). The characteristic lithofacies are the Gresten Beds of Early Jurassic age that are covered by a sequence of marly and silty beds with intercalated sandy limestones. Permanent data acquisition can be implemented into our workflow with any long-range TLS system offering fully automated capturing. We utilize an Optech ILRIS-3D scanner. The time interval between two scans is currently set to 24 hours, but can be

  17. Dual energy micro CT SkyScan 1173 for the characterization of urinary stone

    NASA Astrophysics Data System (ADS)

    Fitri, L. A.; Asyana, V.; Ridwan, T.; Anwary, F.; Soekersi, H.; Latief, F. D. E.; Haryanto, F.

    2016-03-01

    Knowledge of the composition of urinary stones is an essential part to determine suitable treatments for patients. The aim of this research is to characterize the urinary stones by using dual energy micro CT SkyScan 11173. This technique combines high-energy and low- energy scanning during a single acquisition. Six human urinary stones were scanned in vitro using 80 kV and 120 kV micro CT SkyScan 1173. Projected images were produced by micro CT SkyScan 1173 and then reconstructed using NRecon (in-house software from SkyScan) to obtain a complete 3D image. The urinary stone images were analysed using CT analyser to obtain information of internal structure and Hounsfield Unit (HU) values to determine the information regarding the composition of the urinary stones, respectively. HU values obtained from some regions of interest in the same slice are compared to a reference HU. The analysis shows information of the composition of the six scanned stones obtained. The six stones consist of stone number 1 (calcium+cystine), number 2 (calcium+struvite), number 3 (calcium+cystine+struvite), number 4 (calcium), number 5 (calcium+cystine+struvite), and number 6 (calcium+uric acid). This shows that dual energy micro CT SkyScan 1173 was able to characterize the composition of the urinary stone.

  18. Development of the 3D volumetric micro-CT scanner for preclinical animals

    NASA Astrophysics Data System (ADS)

    Kim, Kyong-Woo; Kim, Kyu-Gyeom; Kim, Jae-Hee; Min, Jong-Hwan; Lee, Hee-Sin; Lee, Joonwhoan

    2011-06-01

    A high resolution micro computed tomography (micro-CT) system for live small animal imaging has been developed. The system consists of an x-ray source with micro focus spot and high brightness, rotating gantry with a x-ray tube and flat panel detector pair and a stationary and a horizontally positioned small animal bed to achieve a conebeam mode scan. The system is optimized for in vivo small animal imaging and the capability of administering respiratory anesthesia during scanning. The Feldkamp algorithm was adopted in image reconstruction with graphic processing unit (GPU). We evaluated the spatial resolution, image contrast, and uniformity of system using phantom. As the result, the spatial resolution of the system was the 56lp/mm at 10% of the MTF curve, and the radiation dose to the sample was 98mGy. The minimal resolving contrast was found to be less than 46 CT numbers on low-contrast phantom. We present the image test results of the bone and lung, and heart of the live mice. [Figure not available: see fulltext.

  19. Application of a Hybrid 3D-2D Laser Scanning System to the Characterization of Slate Slabs

    PubMed Central

    López, Marcos; Martínez, Javier; Matías, José María; Vilán, José Antonio; Taboada, Javier

    2010-01-01

    Dimensional control based on 3D laser scanning techniques is widely used in practice. We describe the application of a hybrid 3D-2D laser scanning system to the characterization of slate slabs with structural defects that are difficult for the human eye to characterize objectively. Our study is based on automating the process using a 3D laser scanner and a 2D camera. Our results demonstrate that the application of this hybrid system optimally characterizes slate slabs in terms of the defects described by the Spanish UNE-EN 12326-1 standard. PMID:22219696

  20. 3D imaging of mammalian cells with ion-abrasion scanning electron microscopy.

    PubMed

    Heymann, Jurgen A W; Shi, Dan; Kim, Sang; Bliss, Donald; Milne, Jacqueline L S; Subramaniam, Sriram

    2009-04-01

    Understanding the hierarchical organization of molecules and organelles within the interior of large eukaryotic cells is a challenge of fundamental interest in cell biology. We are using ion-abrasion scanning electron microscopy (IA-SEM) to visualize this hierarchical organization in an approach that combines focused ion-beam milling with scanning electron microscopy. Here, we extend our previous studies on imaging yeast cells to image subcellular architecture in human melanoma cells and melanocytes at resolutions as high as approximately 6 and approximately 20 nm in the directions parallel and perpendicular, respectively, to the direction of ion-beam milling. The 3D images demonstrate the striking spatial relationships between specific organelles such as mitochondria and membranes of the endoplasmic reticulum, and the distribution of unique cellular components such as melanosomes. We also show that 10nm-sized gold particles and quantum dot particles with 7 nm-sized cores can be detected in single cross-sectional images. IA-SEM is thus a useful tool for imaging large mammalian cells in their entirety at resolutions in the nanometer range. PMID:19116171

  1. Automated analysis of barley organs using 3D laser scanning: an approach for high throughput phenotyping.

    PubMed

    Paulus, Stefan; Dupuis, Jan; Riedel, Sebastian; Kuhlmann, Heiner

    2014-01-01

    Due to the rise of laser scanning the 3D geometry of plant architecture is easy to acquire. Nevertheless, an automated interpretation and, finally, the segmentation into functional groups are still difficult to achieve. Two barley plants were scanned in a time course, and the organs were separated by applying a histogram-based classification algorithm. The leaf organs were represented by meshing algorithms, while the stem organs were parameterized by a least-squares cylinder approximation. We introduced surface feature histograms with an accuracy of 96% for the separation of the barley organs, leaf and stem. This enables growth monitoring in a time course for barley plants. Its reliability was demonstrated by a comparison with manually fitted parameters with a correlation R(2) = 0:99 for the leaf area and R(2) = 0:98 for the cumulated stem height. A proof of concept has been given for its applicability for the detection of water stress in barley, where the extension growth of an irrigated and a non-irrigated plant has been monitored. PMID:25029283

  2. Automated Analysis of Barley Organs Using 3D Laser Scanning: An Approach for High Throughput Phenotyping

    PubMed Central

    Paulus, Stefan; Dupuis, Jan; Riedel, Sebastian; Kuhlmann, Heiner

    2014-01-01

    Due to the rise of laser scanning the 3D geometry of plant architecture is easy to acquire. Nevertheless, an automated interpretation and, finally, the segmentation into functional groups are still difficult to achieve. Two barley plants were scanned in a time course, and the organs were separated by applying a histogram-based classification algorithm. The leaf organs were represented by meshing algorithms, while the stem organs were parameterized by a least-squares cylinder approximation. We introduced surface feature histograms with an accuracy of 96% for the separation of the barley organs, leaf and stem. This enables growth monitoring in a time course for barley plants. Its reliability was demonstrated by a comparison with manually fitted parameters with a correlation R2 = 0.99 for the leaf area and R2 = 0.98 for the cumulated stem height. A proof of concept has been given for its applicability for the detection of water stress in barley, where the extension growth of an irrigated and a non-irrigated plant has been monitored. PMID:25029283

  3. Accuracy of 3D white light scanning of abutment teeth impressions: evaluation of trueness and precision

    PubMed Central

    Jeon, Jin-Hun; Kim, Hae-Young; Kim, Ji-Hwan

    2014-01-01

    PURPOSE This study aimed to evaluate the accuracy of digitizing dental impressions of abutment teeth using a white light scanner and to compare the findings among teeth types. MATERIALS AND METHODS To assess precision, impressions of the canine, premolar, and molar prepared to receive all-ceramic crowns were repeatedly scanned to obtain five sets of 3-D data (STL files). Point clouds were compared and error sizes were measured (n=10 per type). Next, to evaluate trueness, impressions of teeth were rotated by 10°-20° and scanned. The obtained data were compared with the first set of data for precision assessment, and the error sizes were measured (n=5 per type). The Kruskal-Wallis test was performed to evaluate precision and trueness among three teeth types, and post-hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction (α=.05). RESULTS Precision discrepancies for the canine, premolar, and molar were 3.7 µm, 3.2 µm, and 7.3 µm, respectively, indicating the poorest precision for the molar (P<.001). Trueness discrepancies for teeth types were 6.2 µm, 11.2 µm, and 21.8 µm, respectively, indicating the poorest trueness for the molar (P=.007). CONCLUSION In respect to accuracy the molar showed the largest discrepancies compared with the canine and premolar. Digitizing of dental impressions of abutment teeth using a white light scanner was assessed to be a highly accurate method and provided discrepancy values in a clinically acceptable range. Further study is needed to improve digitizing performance of white light scanning in axial wall. PMID:25551007

  4. Location constraint based 2D-3D registration of fluoroscopic images and CT volumes for image-guided EP procedures

    NASA Astrophysics Data System (ADS)

    Liao, Rui; Xu, Ning; Sun, Yiyong

    2008-03-01

    Presentation of detailed anatomical structures via 3D Computed Tomographic (CT) volumes helps visualization and navigation in electrophysiology procedures (EP). Registration of the CT volume with the online fluoroscopy however is a challenging task for EP applications due to the lack of discernable features in fluoroscopic images. In this paper, we propose to use the coronary sinus (CS) catheter in bi-plane fluoroscopic images and the coronary sinus in the CT volume as a location constraint to accomplish 2D-3D registration. Two automatic registration algorithms are proposed in this study, and their performances are investigated on both simulated and real data. It is shown that compared to registration using mono-plane fluoroscopy, registration using bi-plane images results in substantially higher accuracy in 3D and enhanced robustness. In addition, compared to registering the projection of CS to the 2D CS catheter, it is more desirable to reconstruct a 3D CS catheter from the bi-plane fluoroscopy and then perform a 3D-3D registration between the CS and the reconstructed CS catheter. Quantitative validation based on simulation and visual inspection on real data demonstrates the feasibility of the proposed workflow in EP procedures.

  5. Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data

    NASA Astrophysics Data System (ADS)

    van der Bom, M. J.; Pluim, J. P. W.; Gounis, M. J.; van de Kraats, E. B.; Sprinkhuizen, S. M.; Timmer, J.; Homan, R.; Bartels, L. W.

    2011-02-01

    Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data is not a trivial task because of their fundamental difference in tissue contrast. This paper presents a technique that generates pseudo-computed tomography (CT) data from multi-spectral MRI acquisitions which is sufficiently similar to real CT data to enable registration of x-ray to MRI with comparable accuracy as registration of x-ray to CT. The method is based on a k-nearest-neighbors (kNN)-regression strategy which labels voxels of MRI data with CT Hounsfield Units. The regression method uses multi-spectral MRI intensities and intensity gradients as features to discriminate between various tissue types. The efficacy of using pseudo-CT data for registration of x-ray to MRI was tested on ex vivo animal data. 2D-3D registration experiments using CT and pseudo-CT data of multiple subjects were performed with a commonly used 2D-3D registration algorithm. On average, the median target registration error for registration of two x-ray images to MRI data was approximately 1 mm larger than for x-ray to CT registration. The authors have shown that pseudo-CT data generated from multi-spectral MRI facilitate registration of MRI to x-ray images. From the experiments it could be concluded that the accuracy achieved was comparable to that of registering x-ray images to CT data.

  6. Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

    NASA Astrophysics Data System (ADS)

    Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

    2015-03-01

    Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

  7. Best fit refractive index of matching liquid for 3D NIPAM gel dosimeters using optical CT

    NASA Astrophysics Data System (ADS)

    Chen, Chin-Hsing; Wu, Jay; Hsieh, Bor-Tsung; Chen, De-Shiou; Wang, Tzu-Hwei; Chien, Sou-Hsin; Chang, Yuan-Jen

    2014-11-01

    The accuracy of an optical computed tomography (CT)-based dosimeter is significantly affected by the refractive index (RI) of the matching liquid. Mismatched RI induces reflection and refraction as the laser beam passes through the gel phantom. Moreover, the unwanted light rays collected by the photodetector produce image artifacts after image reconstruction from the collected data. To obtain the best image quality, this study investigates the best-fit RI of the matching liquid for a 3D NIPAM gel dosimeter. The three recipes of NIPAM polymer gel used in this study consisted of 5% gelatin, 5% NIPAM and 3% N,N'-methylene bisacrylamide, which were combined with three compositions (5, 10, and 20 mM) of Tetrakis (hydroxymethyl) phosphonium chloride. Results were evaluated using a quantitative evaluation method of the gamma evaluation technique. Results showed that the best-fit RI for the non-irradiated NIPAM gel ranges from 1.340 to 1.346 for various NIPAM recipes with sensitivities ranging from 0.0113 to 0.0227. The greatest pass rate of 88.00% is achieved using best-fit RI=1.346 of the matching liquid. The adoption of mismatching RI decreases the gamma pass rate by 2.63% to 16.75% for all three recipes of NIPAM gel dosimeters. In addition, the maximum average deviation is less than 0.1% for the red and transparent matching liquids. Thus, the color of the matching liquid does not affect the measurement accuracy of the NIPAM gel dosimeter, as measured by optical CT.

  8. Vertical Scan (V-SCAN) for 3-D Grid Adaptive Mesh Refinement for an atmospheric Model Dynamical Core

    NASA Astrophysics Data System (ADS)

    Andronova, N. G.; Vandenberg, D.; Oehmke, R.; Stout, Q. F.; Penner, J. E.

    2009-12-01

    One of the major building blocks of a rigorous representation of cloud evolution in global atmospheric models is a parallel adaptive grid MPI-based communication library (an Adaptive Blocks for Locally Cartesian Topologies library -- ABLCarT), which manages the block-structured data layout, handles ghost cell updates among neighboring blocks and splits a block as refinements occur. The library has several modules that provide a layer of abstraction for adaptive refinement: blocks, which contain individual cells of user data; shells - the global geometry for the problem, including a sphere, reduced sphere, and now a 3D sphere; a load balancer for placement of blocks onto processors; and a communication support layer which encapsulates all data movement. A major performance concern with adaptive mesh refinement is how to represent calculations that have need to be sequenced in a particular order in a direction, such as calculating integrals along a specific path (e.g. atmospheric pressure or geopotential in the vertical dimension). This concern is compounded if the blocks have varying levels of refinement, or are scattered across different processors, as can be the case in parallel computing. In this paper we describe an implementation in ABLCarT of a vertical scan operation, which allows computing along vertical paths in the correct order across blocks transparent to their resolution and processor location. We test this functionality on a 2D and a 3D advection problem, which tests the performance of the model’s dynamics (transport) and physics (sources and sinks) for different model resolutions needed for inclusion of cloud formation.

  9. Use of 3D imaging in CT of the acute trauma patient: impact of a PACS-based software package.

    PubMed

    Soto, Jorge A; Lucey, Brain C; Stuhlfaut, Joshua W; Varghese, Jose C

    2005-04-01

    To evaluate the impact of a picture archiving and communication systems (PACS)-based software package on the requests for 3D reconstructions of multidetector CT (MDCT) data sets in the emergency radiology of a level 1 trauma center, we reviewed the number and type of physician requests for 3D reconstructions of MDCT data sets for patients admitted after sustaining multiple trauma, during a 12-month period (January 2003-December 2003). During the first 5 months of the study, 3D reconstructions were performed in dedicated workstations located separately from the emergency radiology CT interpretation area. During the last 7 months of the study, reconstructions were performed online by the attending radiologist or resident on duty, using a software package directly incorporated into the PACS workstations. The mean monthly number of 3D reconstructions requested during the two time periods was compared using Student's t test. The monthly mean +/- SD of 3D reconstructions performed before and after 3D software incorporation into the PACS was 34+/-7 (95% CI, 10-58) and 132+/-31 (95% CI, 111-153), respectively. This difference was statistically significant (p<0.0001). In the multiple trauma patient, implementation of PACS-integrated software increases utilization of 3D reconstructions of MDCT data sets. PMID:16028324

  10. Clinical Application of Solid Model Based on Trabecular Tibia Bone CT Images Created by 3D Printer

    PubMed Central

    Cho, Jaemo; Park, Chan-Soo; Kim, Yeoun-Jae

    2015-01-01

    Objectives The aim of this work is to use a 3D solid model to predict the mechanical loads of human bone fracture risk associated with bone disease conditions according to biomechanical engineering parameters. Methods We used special image processing tools for image segmentation and three-dimensional (3D) reconstruction to generate meshes, which are necessary for the production of a solid model with a 3D printer from computed tomography (CT) images of the human tibia's trabecular and cortical bones. We examined the defects of the mechanism for the tibia's trabecular bones. Results Image processing tools and segmentation techniques were used to analyze bone structures and produce a solid model with a 3D printer. Conclusions These days, bio-imaging (CT and magnetic resonance imaging) devices are able to display and reconstruct 3D anatomical details, and diagnostics are becoming increasingly vital to the quality of patient treatment planning and clinical treatment. Furthermore, radiographic images are being used to study biomechanical systems with several aims, namely, to describe and simulate the mechanical behavior of certain anatomical systems, to analyze pathological bone conditions, to study tissues structure and properties, and to create a solid model using a 3D printer to support surgical planning and reduce experimental costs. These days, research using image processing tools and segmentation techniques to analyze bone structures to produce a solid model with a 3D printer is rapidly becoming very important. PMID:26279958

  11. Physical evaluation of CT scan methods for radiation therapy planning: comparison of fast, slow and gating scan using the 256-detector row CT scanner

    NASA Astrophysics Data System (ADS)

    Mori, Shinichiro; Kanematsu, Nobuyuki; Mizuno, Hideyuki; Sunaoka, Masayoshi; Endo, Masahiro

    2006-02-01

    Although slow-rotation CT scanning (slow-scan CT: SSCT) has been used for radiation therapy planning, based on the rationale that the average duration of the human respiratory cycle is 4 s, a number of physical and quantitative questions require answering before it can be adopted for clinical use. This study was performed to evaluate SSCT physically in comparison with other scan methods, including respiratory-gated CT (RGCT), and to develop procedures to improve treatment accuracy. Evaluation items were geometrical accuracy, volume accuracy, water equivalent length and dose distribution using the 256-detector row CT with three scan methods. Fast-scan CT (FSCT) was defined as obtaining all respiratory phases in cine scan mode at 1.0 s per rotation. FSCT-ave was the averaged FSCT images in all respiratory phases, obtained by reconstructing short time intervals. SSCT has been defined as scanning with slow gantry rotation to capture the whole respiratory cycle in one rotation. RGCT was scanned at the most stable point in the respiratory cycle, which provides the same image as that by FSCT at the most stable point. Results showed that all evaluation items were dependent on motion characteristics. The findings of this study indicate that 3D planning based solely on SSCT under free breathing may result in underdosing of the target volume and increase toxicity to surrounding normal tissues. Of the three methods, RGCT showed the best ability to significantly increase the accuracy of dose distribution, and provided more information to minimize the margins. FSCT-ave is a satisfactory radiotherapy planning alternative if RGCT is not available.

  12. 3D segmentation of non-isolated pulmonary nodules in high resolution CT images

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangwei; McLennan, Geoffrey; Hoffman, Eric A.; Sonka, Milan

    2005-04-01

    The purpose of this study is to develop a computer-aided diagnosis (CAD) system to segment small size non-isolated pulmonary nodules in high resolution helical CT scans. A new automated method of segmenting juxtapleural nodules was proposed, in which a quadric surface fitting procedure was used to create a boundary between a juxtapleural nodule and its neighboring pleural surface. Experiments on some real CT nodule data showed that this method was able to yield results that reflect the local shape of the pleural surface. Additionally, a scheme based on parametrically deformable geometric model was developed to deal with the problem of segmenting nodules attached to vessels. A vessel segment connected to a nodule was modeled using superquadrics with parametric deformations. The boundary between a vascularized nodule and the attached vessels can be recovered by finding the deformed superquadrics which approximates the vessels. Gradient descent scheme was utilized to optimize the parameters of the superquadrics. Simple experiments on synthetic data showed this scheme is promising.

  13. A primary study of appropriate intraoral scanning frequency of single 3D image

    NASA Astrophysics Data System (ADS)

    Li, Hong; Lyu, Peijun; Sun, Yuchun; Wang, Yong; Liang, Xiaoyue

    2015-07-01

    Objective To make a quantitative analysis between sampling frequencies and micro-movement distance of mark points on tooth surfaces, and to provide a reference for sampling frequency settings of intraoral scanning systems. Methods Mark points affixed to the incisors of five subjects. In total, 3600 groups of tracking point coordinates were obtained with frequencies of 60, 150 and 300 Hz using an optical 3D tracking system. The data was then re-sampled to obtain coordinates at lower frequencies (5, 10, 15 and 20 Hz) at equal intervals of groups of tracking point coordinates. Change in distance (Δd) was defined as the change in position of a single v from one sampling time point to another, and was valued by clinical accuracy requirement (20-100μm). The curve equation was fit quantitatively between Δd median (M) and the sampling frequency (f). The difference between upper and lower incisor mark points were analyzed by a non-parametric test; α=0.05. Result When the frequency (f) was 60 Hz, upper jaw Δd median (M) and interquartile (Q) were 14.4 μm and 9.2 μm, respectively, while the lower Δd(M) and (Q) were 6.4 μm and 10.2 μm, respectively. Every Δd value was less than 100 μm, while 74% of Δd vales were less than 20 μm. Δd(M) and f satisfy the power curve equation: Δd(M)=0.526×f-0.979(f∈[5,300]). Significant differences of incisor feature points were noted between upper and lower jaws of the same subject (P<0.01). Conclusion Clinical accuracy can be met when the sampling frequency of the intraoral scanning system is 60 Hz.

  14. Imaging the Aqueous Humor Outflow Pathway in Human Eyes by Three-dimensional Micro-computed Tomography (3D micro-CT)

    SciTech Connect

    C Hann; M Bentley; A Vercnocke; E Ritman; M Fautsch

    2011-12-31

    The site of outflow resistance leading to elevated intraocular pressure in primary open-angle glaucoma is believed to be located in the region of Schlemm's canal inner wall endothelium, its basement membrane and the adjacent juxtacanalicular tissue. Evidence also suggests collector channels and intrascleral vessels may have a role in intraocular pressure in both normal and glaucoma eyes. Traditional imaging modalities limit the ability to view both proximal and distal portions of the trabecular outflow pathway as a single unit. In this study, we examined the effectiveness of three-dimensional micro-computed tomography (3D micro-CT) as a potential method to view the trabecular outflow pathway. Two normal human eyes were used: one immersion fixed in 4% paraformaldehyde and one with anterior chamber perfusion at 10 mmHg followed by perfusion fixation in 4% paraformaldehyde/2% glutaraldehyde. Both eyes were postfixed in 1% osmium tetroxide and scanned with 3D micro-CT at 2 {mu}m or 5 {mu}m voxel resolution. In the immersion fixed eye, 24 collector channels were identified with an average orifice size of 27.5 {+-} 5 {mu}m. In comparison, the perfusion fixed eye had 29 collector channels with a mean orifice size of 40.5 {+-} 13 {mu}m. Collector channels were not evenly dispersed around the circumference of the eye. There was no significant difference in the length of Schlemm's canal in the immersed versus the perfused eye (33.2 versus 35.1 mm). Structures, locations and size measurements identified by 3D micro-CT were confirmed by correlative light microscopy. These findings confirm 3D micro-CT can be used effectively for the non-invasive examination of the trabecular meshwork, Schlemm's canal, collector channels and intrascleral vasculature that comprise the distal outflow pathway. This imaging modality will be useful for non-invasive study of the role of the trabecular outflow pathway as a whole unit.

  15. Mapping motion from 4D-MRI to 3D-CT for use in 4D dose calculations: A technical feasibility study

    SciTech Connect

    Boye, Dirk; Lomax, Tony; Knopf, Antje

    2013-06-15

    Purpose: Target sites affected by organ motion require a time resolved (4D) dose calculation. Typical 4D dose calculations use 4D-CT as a basis. Unfortunately, 4D-CT images have the disadvantage of being a 'snap-shot' of the motion during acquisition and of assuming regularity of breathing. In addition, 4D-CT acquisitions involve a substantial additional dose burden to the patient making many, repeated 4D-CT acquisitions undesirable. Here the authors test the feasibility of an alternative approach to generate patient specific 4D-CT data sets. Methods: In this approach motion information is extracted from 4D-MRI. Simulated 4D-CT data sets [which the authors call 4D-CT(MRI)] are created by warping extracted deformation fields to a static 3D-CT data set. The employment of 4D-MRI sequences for this has the advantage that no assumptions on breathing regularity are made, irregularities in breathing can be studied and, if necessary, many repeat imaging studies (and consequently simulated 4D-CT data sets) can be performed on patients and/or volunteers. The accuracy of 4D-CT(MRI)s has been validated by 4D proton dose calculations. Our 4D dose algorithm takes into account displacements as well as deformations on the originating 4D-CT/4D-CT(MRI) by calculating the dose of each pencil beam based on an individual time stamp of when that pencil beam is applied. According to corresponding displacement and density-variation-maps the position and the water equivalent range of the dose grid points is adjusted at each time instance. Results: 4D dose distributions, using 4D-CT(MRI) data sets as input were compared to results based on a reference conventional 4D-CT data set capturing similar motion characteristics. Almost identical 4D dose distributions could be achieved, even though scanned proton beams are very sensitive to small differences in the patient geometry. In addition, 4D dose calculations have been performed on the same patient, but using 4D-CT(MRI) data sets based on

  16. Application of offset-CT scanning to the inspection of high power feeder lines and connections

    NASA Astrophysics Data System (ADS)

    Schneberk, Daniel; Maziuk, Robert; Soyfer, Boris; Shashishekhar, N.; Alreja, Rahul

    2016-02-01

    VJT is developing techniques and scanning methods for the in-situ Radiographic and Computed Tomographic inspection of underground high-power feeder cables. The goals for the inspection are to measure the 3D state of the cables and the cable-connections. Recent in-situ Digital Radiographic inspections performed by VJT have demonstrated the value of NDE inspection information for buried power lines. These NDE data have raised further questions as to the exact state of the cables and connections and pointed to the need for more 3D information of the type provided by volumetric CT scanning. VJT is pursuing a three phased approach to address the many issues involved in this type of inspection: 1) develop a high-power feeder-cable test-bed CT scanner, 2) acquire scans on underground feeder pipes that have been removed from service, and 3) from the work in 1) and 2) develop limited-angle CT scanning methods for extending in-situ Digital Radiography to volumetric CT measurements. To this end, VJT has developed and fielded a high-energy test-bed Gantry-type CT scanner (the source and detector move around the object) with a number of important properties. First, the geometry of the gantry-scans can be configured to match the techniques used in the in-situ radiographic inspection. The same X-ray source is employed as in portable Radiographic inspections, a 7.5 MeV Betatron coupled to a Perkin-Elmer Amorphous Silicon detector. Offset-CT scanning is employed as the high-power feeder line assembly is larger than the detector. A description of this scanner and the scan geometry will be presented showing the connection to in-situ radiography. Results from the CT scans of high-power feeder-cable specimens removed from service will be presented with a focus on the inspection potential of volumetric CT data on these assemblies. An evaluation of the scan performance properties of these data compared to the spectrum of life-cycle inspection issues will be presented. Continuing and

  17. Studying post depositional damage on Acheulian bifaces using 3-D scanning.

    PubMed

    Grosman, Leore; Sharon, Gonen; Goldman-Neuman, Talia; Smikt, Oded; Smilansky, Uzy

    2011-04-01

    In this study, we explore post-depositional damage observed on Acheulian bifacial tools by comparing two assemblages: a collection of archaeological handaxes which shows pronounced damage marks associated with high energy water accumulation system, and an experimental assemblage that was rolled and battered in a controlled simulation experiment. Scanning the two assemblages with a precise 3-D optical scanner and subjecting the measured surfaces to the same mathematical analysis enabled the development of quantitative measures assessing and comparing the degree of damage observed on archaeological and experimental tools. The method presented here enables the definition of morphological patterns typically resulting from battering and different from intentional controlled knapping. The most important kinds of damage included the formation of deep, random 'notch-like' scars on the lateral edges and substantial degrees of damage to the tip of the tools, but minimal damage to the artifact's butt. Quantifying the degree of damage and its location and morphological characters allows us to present a method by which post depositional damage on archaeological tools can be measured. PMID:20304464

  18. A real-time 3D scanning system for pavement rutting and pothole detections

    NASA Astrophysics Data System (ADS)

    Li, Qingguang; Yao, Ming; Yao, Xun; Yu, Wurong; Xu, Bugao

    2009-08-01

    Rutting and pothole are the common pavement distress problems that need to be timely inspected and repaired to ensure ride quality and safe traffic. This paper introduces a real-time, automated inspection system devoted for detecting these distress features using high-speed transverse scanning. The detection principle is based on the dynamic generation and characterization of 3D pavement profiles obtained from structured light measurements. The system implementation mainly involves three tasks: multi-view coplanar calibration, sub-pixel laser stripe location, and pavement distress recognition. The multi-view coplanar scheme was employed in the calibration procedure to increase the feature points and to make the points distributed across the field of view of the camera, which greatly improves the calibration precision. The laser stripe locating method was implemented in four steps: median filtering, coarse edge detection, fine edge adjusting, stripe curve mending and interpolation by cubic splines. The pavement distress recognition algorithms include line segment approximation of the profile, searching for the feature points, and parameters calculations. The parameter data of a curve segment between two feature points, such as width, depth and length, were used to differentiate rutting, pothole, and pothole under different constraints. The preliminary experiment results show that the system is capable of locating these pavement distresses, and meets the needs for real-time and accurate pavement inspection.

  19. Building a 3d Reference Model for Canal Tunnel Surveying Using Sonar and Laser Scanning

    NASA Astrophysics Data System (ADS)

    Moisan, E.; Charbonnier, P.; Foucher, P.; Grussenmeyer, P.; Guillemin, S.; Koehl, M.

    2015-04-01

    Maintaining canal tunnels is not only a matter of cultural and historical preservation, but also a commercial necessity and a security issue. This contribution adresses the problem of building a full 3D reference model of a canal tunnel by merging SONAR (for underwater data recording) and LASER data (for the above-water parts). Although both scanning devices produce point clouds, their properties are rather different. In particular, SONAR data are very noisy and their processing raises several issues related to the device capacities, the acquisition setup and the tubular shape of the tunnel. The proposed methodology relies on a denoising step by meshing, followed by the registration of SONAR data with the geo-referenced LASER data. Since there is no overlap between point clouds, a 3-step procedure is proposed to robustly estimate the registration parameters. In this paper, we report a first experimental survey, which concerned the entrance of a canal tunnel. The obtained results are promising and the analysis of the method raises several improvement directions that will help obtaining more accurate models, in a more automated fashion, in the limits of the involved technology.

  20. Scanned bi-orthogonal radiographs as a source for 3D cephalometric data

    NASA Astrophysics Data System (ADS)

    Subramanyan, Krishna; Dean, David

    1996-04-01

    We have developed a visualization environment, CEPH, for the analysis of plain film, biothogonally registered, head x-rays, i.e., cephalograms. Most importantly this program facilitates the collection of 3D landmark data from biorthogonal cephalogram pairs, i.e., correlated frontal and lateral images. To this end we have implemented tools for: contrast enhancement, image compression, morphological feature extraction, and grayscale shape recognition for automatic landmark detection. These data are useful for clinical craniofacial: (1) diagnosis, (2) treatment planning, (3) computed-assisted surgery, and (4) post-procedure follow-up. We are currently using the CEPH visualization environment to produce average landmark sets from the nearly 2000 'Bolton Standards' images. These images were collected for the Bolton-Brush Growth Study at Case Western Reserve University. Two dimensional landmark data captured from these images are universally recognized and used as diagnostic and treatment 'norms.' We are planning to make new three dimensional Bolton Standards data available this year. To this end we have scanned all of the Bolton Standards cephalograms at 2400 by 2400 resolution with 12 bits of grayscale information on a TDI scanner.

  1. Size-based emphysema cluster analysis on low attenuation area in 3D volumetric CT: comparison with pulmonary functional test

    NASA Astrophysics Data System (ADS)

    Lee, Minho; Kim, Namkug; Lee, Sang Min; Seo, Joon Beom; Oh, Sang Young

    2015-03-01

    To quantify low attenuation area (LAA) of emphysematous regions according to cluster size in 3D volumetric CT data of chronic obstructive pulmonary disease (COPD) patients and to compare these indices with their pulmonary functional test (PFT). Sixty patients with COPD were scanned by a more than 16-multi detector row CT scanner (Siemens Sensation 16 and 64) within 0.75mm collimation. Based on these LAA masks, a length scale analysis to estimate each emphysema LAA's size was performed as follows. At first, Gaussian low pass filter from 30mm to 1mm kernel size with 1mm interval on the mask was performed from large to small size, iteratively. Centroid voxels resistant to the each filter were selected and dilated by the size of the kernel, which was regarded as the specific size emphysema mask. The slopes of area and number of size based LAA (slope of semi-log plot) were analyzed and compared with PFT. PFT parameters including DLco, FEV1, and FEV1/FVC were significantly (all p-value< 0.002) correlated with the slopes (r-values; -0.73, 0.54, 0.69, respectively) and EI (r-values; -0.84, -0.60, -0.68, respectively). In addition, the D independently contributed regression for FEV1 and FEV1/FVC (adjust R sq. of regression study: EI only, 0.70, 0.45; EI and D, 0.71, 0.51, respectively). By the size based LAA segmentation and analysis, we evaluated the Ds of area, number, and distribution of size based LAA, which would be independent factors for predictor of PFT parameters.

  2. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

    NASA Astrophysics Data System (ADS)

    Welch, D.; Harken, A. D.; Randers-Pehrson, G.; Brenner, D. J.

    2015-05-01

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions.

  3. Construction of mouse phantoms from segmented CT scan data for radiation dosimetry studies

    PubMed Central

    Welch, D; Harken, A D; Randers-Pehrson, G; Brenner, D J

    2015-01-01

    We present the complete construction methodology for an anatomically accurate mouse phantom made using materials which mimic the characteristics of tissue, lung, and bone for radiation dosimetry studies. Phantoms were constructed using 2 mm thick slices of tissue equivalent material which was precision machined to clear regions for insertion of lung and bone equivalent material where appropriate. Images obtained using a 3D computed tomography (CT) scan clearly indicate regions of tissue, lung, and bone that match their position within the original mouse CT scan. Additionally, radiographic films are used with the phantom to demonstrate dose mapping capabilities. The construction methodology presented here can be quickly and easily adapted to create a phantom of any specific small animal given a segmented CT scan of the animal. These physical phantoms are a useful tool to examine individual organ dose and dosimetry within mouse systems that are complicated by density inhomogeneity due to bone and lung regions. PMID:25860401

  4. 3D Riesz-wavelet based Covariance descriptors for texture classification of lung nodule tissue in CT.

    PubMed

    Cirujeda, Pol; Muller, Henning; Rubin, Daniel; Aguilera, Todd A; Loo, Billy W; Diehn, Maximilian; Binefa, Xavier; Depeursinge, Adrien

    2015-08-01

    In this paper we present a novel technique for characterizing and classifying 3D textured volumes belonging to different lung tissue types in 3D CT images. We build a volume-based 3D descriptor, robust to changes of size, rigid spatial transformations and texture variability, thanks to the integration of Riesz-wavelet features within a Covariance-based descriptor formulation. 3D Riesz features characterize the morphology of tissue density due to their response to changes in intensity in CT images. These features are encoded in a Covariance-based descriptor formulation: this provides a compact and flexible representation thanks to the use of feature variations rather than dense features themselves and adds robustness to spatial changes. Furthermore, the particular symmetric definite positive matrix form of these descriptors causes them to lay in a Riemannian manifold. Thus, descriptors can be compared with analytical measures, and accurate techniques from machine learning and clustering can be adapted to their spatial domain. Additionally we present a classification model following a "Bag of Covariance Descriptors" paradigm in order to distinguish three different nodule tissue types in CT: solid, ground-glass opacity, and healthy lung. The method is evaluated on top of an acquired dataset of 95 patients with manually delineated ground truth by radiation oncology specialists in 3D, and quantitative sensitivity and specificity values are presented. PMID:26738126

  5. 3D texture analysis of solitary pulmonary nodules using co-occurrence matrix from volumetric lung CT images

    NASA Astrophysics Data System (ADS)

    Dhara, Ashis Kumar; Mukhopadhyay, Sudipta; Khandelwal, Niranjan

    2013-02-01

    In this paper we have investigated a new approach for texture features extraction using co-occurrence matrix from volumetric lung CT image. Traditionally texture analysis is performed in 2D and is suitable for images collected from 2D imaging modality. The use of 3D imaging modalities provide the scope of texture analysis from 3D object and 3D texture feature are more realistic to represent 3D object. In this work, Haralick's texture features are extended in 3D and computed from volumetric data considering 26 neighbors. The optimal texture features to characterize the internal structure of Solitary Pulmonary Nodules (SPN) are selected based on area under curve (AUC) values of ROC curve and p values from 2-tailed Student's t-test. The selected texture feature in 3D to represent SPN can be used in efficient Computer Aided Diagnostic (CAD) design plays an important role in fast and accurate lung cancer screening. The reduced number of input features to the CAD system will decrease the computational time and classification errors caused by irrelevant features. In the present work, SPN are classified from Ground Glass Nodule (GGN) using Artificial Neural Network (ANN) classifier considering top five 3D texture features and top five 2D texture features separately. The classification is performed on 92 SPN and 25 GGN from Imaging Database Resources Initiative (IDRI) public database and classification accuracy using 3D texture features and 2D texture features provide 97.17% and 89.1% respectively.

  6. Axial-Stereo 3-D Optical Metrology for Inner Profile of Pipes Using a Scanning Laser Endoscope

    NASA Astrophysics Data System (ADS)

    Gong, Yuanzheng; Johnston, Richard S.; Melville, C. David; Seibel, Eric J.

    2015-07-01

    As the rapid progress in the development of optoelectronic components and computational power, 3-D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surfaces. This article proposed a new approach to measure tiny internal 3-D surfaces with a scanning fiber endoscope and axial-stereo vision algorithm. A dense, accurate point cloud of internally machined threads was generated to compare with its corresponding X-ray 3-D data as ground truth, and the quantification was analyzed by Iterative Closest Points algorithm.

  7. 3D multiple optical tweezers based on time-shared scanning with a fast focus tunable lens

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshio

    2013-02-01

    Three-dimensional controlled manipulation of individual micro-objects requires multiple optical tweezers that can be independently controlled in a 3D working space with high spatiotemporal resolution. Here, the author presents 3D multiple optical tweezers based on a time-shared scanning technique with an electrically focus tunable lens for axial steering and a two-axis steering mirror for lateral steering. Four typical examples of 3D controlled manipulation, including the rotation of a single bead on its axis, are demonstrated in real time. The optical system design and the control method are also described.

  8. Axial-Stereo 3-D Optical Metrology for Inner Profile of Pipes Using a Scanning Laser Endoscope

    PubMed Central

    Gong, Yuanzheng; Johnston, Richard S.; Melville, C. David; Seibel, Eric J.

    2015-01-01

    As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surfaces. This paper proposed a new approach to measure tiny internal 3D surfaces with a scanning fiber endoscope and axial-stereo vision algorithm. A dense, accurate point cloud of internally machined threads was generated to compare with its corresponding X-ray 3D data as ground truth, and the quantification was analyzed by Iterative Closest Points algorithm. PMID:26640425

  9. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    PubMed Central

    Yuan, Liang (Leon); Herman, Peter R.

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  10. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors.

    PubMed

    Yuan, Liang Leon; Herman, Peter R

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  11. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    NASA Astrophysics Data System (ADS)

    Yuan, Liang (Leon); Herman, Peter R.

    2016-02-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

  12. Atlas and feature based 3D pathway visualization enhancement for skull base pre-operative fast planning from head CT

    NASA Astrophysics Data System (ADS)

    Aghdasi, Nava; Li, Yangming; Berens, Angelique; Moe, Kris S.; Bly, Randall A.; Hannaford, Blake

    2015-03-01

    Minimally invasive neuroendoscopic surgery provides an alternative to open craniotomy for many skull base lesions. These techniques provides a great benefit to the patient through shorter ICU stays, decreased post-operative pain and quicker return to baseline function. However, density of critical neurovascular structures at the skull base makes planning for these procedures highly complex. Furthermore, additional surgical portals are often used to improve visualization and instrument access, which adds to the complexity of pre-operative planning. Surgical approach planning is currently limited and typically involves review of 2D axial, coronal, and sagittal CT and MRI images. In addition, skull base surgeons manually change the visualization effect to review all possible approaches to the target lesion and achieve an optimal surgical plan. This cumbersome process relies heavily on surgeon experience and it does not allow for 3D visualization. In this paper, we describe a rapid pre-operative planning system for skull base surgery using the following two novel concepts: importance-based highlight and mobile portal. With this innovation, critical areas in the 3D CT model are highlighted based on segmentation results. Mobile portals allow surgeons to review multiple potential entry portals in real-time with improved visualization of critical structures located inside the pathway. To achieve this we used the following methods: (1) novel bone-only atlases were manually generated, (2) orbits and the center of the skull serve as features to quickly pre-align the patient's scan with the atlas, (3) deformable registration technique was used for fine alignment, (4) surgical importance was assigned to each voxel according to a surgical dictionary, and (5) pre-defined transfer function was applied to the processed data to highlight important structures. The proposed idea was fully implemented as independent planning software and additional

  13. Fusion of image and laser-scanning data in a large-scale 3D virtual environment

    NASA Astrophysics Data System (ADS)

    Shih, Jhih-Syuan; Lin, Ta-Te

    2013-05-01

    Construction of large-scale 3D virtual environment is important in many fields such as robotic navigation, urban planning, transportation, and remote sensing, etc. Laser scanning approach is the most common method used in constructing 3D models. This paper proposes an automatic method to fuse image and laser-scanning data in a large-scale 3D virtual environment. The system comprises a laser-scanning device installed on a robot platform and the software for data fusion and visualization. The algorithms of data fusion and scene integration are presented. Experiments were performed for the reconstruction of outdoor scenes to test and demonstrate the functionality of the system. We also discuss the efficacy of the system and technical problems involved in this proposed method.

  14. Investigations into the feasibility of optical-CT 3D dosimetry with minimal use of refractively matched fluids

    PubMed Central

    Chisholm, Kelsey; Miles, Devin; Rankine, Leith; Oldham, Mark

    2015-01-01

    Purpose: In optical-CT, the use of a refractively matched polyurethane solid-tank in place of a fluid bath has the potential to greatly increase practical convenience, reduce cost, and possibly improve the efficacy of flood corrections. This work investigates the feasibility of solid-tank optical-CT imaging for 3D dosimetry through computer simulation. Methods: A matlab ray-tracing simulation platform, ScanSim, was used to model a parallel-source telecentric optical-CT imaging system through a polyurethane solid-tank containing a central cylindrical hollow into which PRESAGE radiochromic dosimeters can be placed. A small amount of fluid fills the 1–5 mm gap between the dosimeter and the walls of the tank. The use of the solid-tank reduces the required amount of fluid by approximately 97%. To characterize the efficacy of solid-tank, optical-CT scanning simulations investigated sensitivity to refractive index (RI) mismatches between dosimeter, solid-tank, and fluid, for a variety of dosimeter (RI = 1.5–1.47) and fluid (RI = 1.55–1.0) combinations. Efficacy was evaluated through the usable radius (ru) metric, defined as the fraction of the radius of the dosimeter where measured dose is predicted to be within 2% of the ground truth entered into the simulation. Additional simulations examined the effect of increasing gap size (1–5 mm) between the dosimeter and solid-tank well. The effects of changing the lens tolerance (0.5°–5.0°) were also investigated. Results: As the RI mismatch between the dosimeter and solid-tank increased from 0 to 0.02, the usable radius decreased from 97.6% to 50.2%. The optimal fluid RI decreased nonlinearly from 1.5 to 1.34 as the mismatch increased and was up to 9% lower than the tank. Media mismatches between the dosimeter and solid-tank also exacerbate the effects of changing the gap size, with no easily quantifiable relationship with usable radius. Generally, the optimal fluid RI value increases as gap size increases and is

  15. Investigations into the feasibility of optical-CT 3D dosimetry with minimal use of refractively matched fluids

    SciTech Connect

    Chisholm, Kelsey; Miles, Devin; Rankine, Leith; Oldham, Mark

    2015-05-15

    Purpose: In optical-CT, the use of a refractively matched polyurethane solid-tank in place of a fluid bath has the potential to greatly increase practical convenience, reduce cost, and possibly improve the efficacy of flood corrections. This work investigates the feasibility of solid-tank optical-CT imaging for 3D dosimetry through computer simulation. Methods: A MATLAB ray-tracing simulation platform, ScanSim, was used to model a parallel-source telecentric optical-CT imaging system through a polyurethane solid-tank containing a central cylindrical hollow into which PRESAGE radiochromic dosimeters can be placed. A small amount of fluid fills the 1–5 mm gap between the dosimeter and the walls of the tank. The use of the solid-tank reduces the required amount of fluid by approximately 97%. To characterize the efficacy of solid-tank, optical-CT scanning simulations investigated sensitivity to refractive index (RI) mismatches between dosimeter, solid-tank, and fluid, for a variety of dosimeter (RI = 1.5–1.47) and fluid (RI = 1.55–1.0) combinations. Efficacy was evaluated through the usable radius (r{sub u}) metric, defined as the fraction of the radius of the dosimeter where measured dose is predicted to be within 2% of the ground truth entered into the simulation. Additional simulations examined the effect of increasing gap size (1–5 mm) between the dosimeter and solid-tank well. The effects of changing the lens tolerance (0.5°–5.0°) were also investigated. Results: As the RI mismatch between the dosimeter and solid-tank increased from 0 to 0.02, the usable radius decreased from 97.6% to 50.2%. The optimal fluid RI decreased nonlinearly from 1.5 to 1.34 as the mismatch increased and was up to 9% lower than the tank. Media mismatches between the dosimeter and solid-tank also exacerbate the effects of changing the gap size, with no easily quantifiable relationship with usable radius. Generally, the optimal fluid RI value increases as gap size increases and

  16. Clinical Utility of 4D FDG-PET/CT Scans in Radiation Treatment Planning

    SciTech Connect

    Aristophanous, Michalis; Sher, David J.; Allen, Aaron M.; Larson, Elysia; Chen, Aileen B.

    2012-01-01

    Purpose: The potential role of four-dimensional (4D) positron emission tomography (PET)/computed tomography (CT) in radiation treatment planning, relative to standard three-dimensional (3D) PET/CT, was examined. Methods and Materials: Ten patients with non-small-cell lung cancer had sequential 3D and 4D [{sup 18}F]fluorodeoxyglucose PET/CT scans in the treatment position prior to radiation therapy. The gross tumor volume and involved lymph nodes were contoured on the PET scan by use of three different techniques: manual contouring by an experienced radiation oncologist using a predetermined protocol; a technique with a constant threshold of standardized uptake value (SUV) greater than 2.5; and an automatic segmentation technique. For each technique, the tumor volume was defined on the 3D scan (VOL3D) and on the 4D scan (VOL4D) by combining the volume defined on each of the five breathing phases individually. The range of tumor motion and the location of each lesion were also recorded, and their influence on the differences observed between VOL3D and VOL4D was investigated. Results: We identified and analyzed 22 distinct lesions, including 9 primary tumors and 13 mediastinal lymph nodes. Mean VOL4D was larger than mean VOL3D with all three techniques, and the difference was statistically significant (p < 0.01). The range of tumor motion and the location of the tumor affected the magnitude of the difference. For one case, all three tumor definition techniques identified volume of moderate uptake of approximately 1 mL in the hilar region on the 4D scan (SUV maximum, 3.3) but not on the 3D scan (SUV maximum, 2.3). Conclusions: In comparison to 3D PET, 4D PET may better define the full physiologic extent of moving tumors and improve radiation treatment planning for lung tumors. In addition, reduction of blurring from free-breathing images may reveal additional information regarding regional disease.

  17. A very low-cost system for capturing 3D motion scans with color and texture data

    NASA Astrophysics Data System (ADS)

    Straub, Jeremy

    2015-05-01

    This paper presents a technique for capturing 3D motion scans using hardware that can be constructed for approximately $5,000 in cost. This hardware-software solution, in addition to capturing the movement of the physical structures also captures color and texture data. The scanner configuration developed at the University of North Dakota is sufficient in size for capturing scans of a group of humans. Scanning starts with synchronization and then requires modeling of each frame. For some applications linking structural elements from frame-to-frame may also be required. The efficacy of this scanning approach is discussed and prospective applications for it are considered.

  18. SU-C-201-06: Utility of Quantitative 3D SPECT/CT Imaging in Patient Specific Internal Dosimetry of 153-Samarium with GATE Monte Carlo Package

    SciTech Connect

    Fallahpoor, M; Abbasi, M; Sen, A; Parach, A; Kalantari, F

    2015-06-15

    Purpose: Patient-specific 3-dimensional (3D) internal dosimetry in targeted radionuclide therapy is essential for efficient treatment. Two major steps to achieve reliable results are: 1) generating quantitative 3D images of radionuclide distribution and attenuation coefficients and 2) using a reliable method for dose calculation based on activity and attenuation map. In this research, internal dosimetry for 153-Samarium (153-Sm) was done by SPECT-CT images coupled GATE Monte Carlo package for internal dosimetry. Methods: A 50 years old woman with bone metastases from breast cancer was prescribed 153-Sm treatment (Gamma: 103keV and beta: 0.81MeV). A SPECT/CT scan was performed with the Siemens Simbia-T scanner. SPECT and CT images were registered using default registration software. SPECT quantification was achieved by compensating for all image degrading factors including body attenuation, Compton scattering and collimator-detector response (CDR). Triple energy window method was used to estimate and eliminate the scattered photons. Iterative ordered-subsets expectation maximization (OSEM) with correction for attenuation and distance-dependent CDR was used for image reconstruction. Bilinear energy mapping is used to convert Hounsfield units in CT image to attenuation map. Organ borders were defined by the itk-SNAP toolkit segmentation on CT image. GATE was then used for internal dose calculation. The Specific Absorbed Fractions (SAFs) and S-values were reported as MIRD schema. Results: The results showed that the largest SAFs and S-values are in osseous organs as expected. S-value for lung is the highest after spine that can be important in 153-Sm therapy. Conclusion: We presented the utility of SPECT-CT images and Monte Carlo for patient-specific dosimetry as a reliable and accurate method. It has several advantages over template-based methods or simplified dose estimation methods. With advent of high speed computers, Monte Carlo can be used for treatment planning

  19. 3D left ventricular extracellular volume fraction by low-radiation dose cardiac CT: Assessment of interstitial myocardial fibrosis

    PubMed Central

    Nacif, Marcelo Souto; Liu, Yixun; Yao, Jianhua; Liu, Songtao; Sibley, Christopher T.; Summers, Ronald M.; Bluemke, David A.

    2014-01-01

    Background Myocardial fibrosis leads to impaired cardiac function and events. Extracellular volume fraction (ECV) assessed with an iodinated contrast agent and measured by cardiac CT may be a useful noninvasive marker of fibrosis. Objective The purpose of this study was to develop and evaluate a 3-dimensional (3D) ECV calculation toolkit (ECVTK) for ECV determination by cardiac CT. Methods Twenty-four subjects (10 systolic heart failure, age, 60 ± 17 years; 5 diastolic failure, age 56 ± 20 years; 9 matched healthy subjects, age 59 ± 7 years) were evaluated. Cardiac CT examinations were done on a 320-multidetector CT scanner before and after 130 mL of iopamidol (Isovue-370; Bracco Diagnostics, Plainsboro, NJ, USA) was administered. A calcium score type sequence was performed before and 7 minutes after contrast with single gantry rotation during 1 breath hold and single cardiac phase acquisition. ECV was calculated as (ΔHUmyocardium/ΔHUblood) × (1 − Hct) where Hct is the hematocrit, and ΔHU is the change in Hounsfield unit attenuation = HUafter iodine − HUbefore iodine. Cardiac magnetic resonance imaging was performed to assess myocardial structure and function. Results Mean 3D ECV values were significantly higher in the subjects with systolic heart failure than in healthy subjects and subjects with diastolic heart failure (mean, 41% ± 6%, 33% ± 2%, and 35% ± 5%, respectively; P = 0.02). Interobserver and intraobserver agreements were excellent for myocardial, blood pool, and ECV (intraclass correlation coefficient, >0.90 for all). Higher 3D ECV by cardiac CT was associated with reduced systolic circumferential strain, greater end-diastolic and -systolic volumes, and lower ejection fraction (r = 0.70, r = 0.60, r = 0.73, and r = −0.68, respectively; all P < 0.001). Conclusion 3D ECV by cardiac CT can be performed with ECVTK. We demonstrated increased ECV in subjects with systolic heart failure compared with healthy subjects. Cardiac CT results also

  20. Web-based 3D digital pathology framework for large-mapping data scanned by FF-OCT

    NASA Astrophysics Data System (ADS)

    Chang, ChiaKai; Tsai, Chien-Chung; Chien, Meng-Ting; Li, Yu-I.; Shun, Chia-Tung; Huang, Sheng-Lung

    2015-03-01

    Full-Field Optical Coherence Tomography (FF-OCT) is a high resolution instrument in 3 dimensional (3D) space, including lateral and longitudinal direction. With FF-OCT, we can perform 3D scanning for excised biopsy or cell culture sample to obtain cellular information. In this work, we have set up a high resolution FF-OCT scanning instrument that can perform cellular resolution tomography scanning of skin tissue for histopathology study. In a scan range of 1cm(x), 1cm(y), 106μm(z), for example, digital data occupies 253 GB capacity. Copying these materials is time consuming, not to mention efficient browsing and analyzing of these data. To solve the problem of information delivery, we have established a network service to browse and analyze the huge volume data.

  1. Methodologies for Development of Patient Specific Bone Models from Human Body CT Scans

    NASA Astrophysics Data System (ADS)

    Chougule, Vikas Narayan; Mulay, Arati Vinayak; Ahuja, Bharatkumar Bhagatraj

    2016-06-01

    This work deals with development of algorithm for physical replication of patient specific human bone and construction of corresponding implants/inserts RP models by using Reverse Engineering approach from non-invasive medical images for surgical purpose. In medical field, the volumetric data i.e. voxel and triangular facet based models are primarily used for bio-modelling and visualization, which requires huge memory space. On the other side, recent advances in Computer Aided Design (CAD) technology provides additional facilities/functions for design, prototyping and manufacturing of any object having freeform surfaces based on boundary representation techniques. This work presents a process to physical replication of 3D rapid prototyping (RP) physical models of human bone from various CAD modeling techniques developed by using 3D point cloud data which is obtained from non-invasive CT/MRI scans in DICOM 3.0 format. This point cloud data is used for construction of 3D CAD model by fitting B-spline curves through these points and then fitting surface between these curve networks by using swept blend techniques. This process also can be achieved by generating the triangular mesh directly from 3D point cloud data without developing any surface model using any commercial CAD software. The generated STL file from 3D point cloud data is used as a basic input for RP process. The Delaunay tetrahedralization approach is used to process the 3D point cloud data to obtain STL file. CT scan data of Metacarpus (human bone) is used as the case study for the generation of the 3D RP model. A 3D physical model of the human bone is generated on rapid prototyping machine and its virtual reality model is presented for visualization. The generated CAD model by different techniques is compared for the accuracy and reliability. The results of this research work are assessed for clinical reliability in replication of human bone in medical field.

  2. 3D registration of micro PET-CT for measurable correlates of dyspeptic symptoms in mice

    NASA Astrophysics Data System (ADS)

    Camp, Jon; Simpson, Kathryn; Bardsley, Michael R.; Popko, Laura N.; Young, David L.; Kemp, Bradley J.; Lowe, Val; Ordog, Tamas; Robb, Richard

    2009-02-01

    Patients with chronic calorie insufficiency commonly suffer from upper gastrointestinal dysfunction and consequent dyspeptic symptoms, which may interfere with their nutritional rehabilitation. To investigate the relationship between gastric dysfunction and feeding behavior, we exposed mice to chronic caloric restriction and demonstrated gastric motor abnormalities in them. Gastric dysmotility is typically associated with dyspeptic symptoms but sensations cannot be directly assessed in animal models. Therefore, as an initial step toward establishing measurable correlates of postprandial symptoms in small animals, we have attempted to characterize central responses to food intake by positron emission tomography-computerized microtomography (PET-CT) in normal and calorically restricted mice. Animals consumed a standard test meal after an overnight fast before receiving 2-deoxy-2[18F]fluoro-D-glucose tracer. The same mice were also scanned in the fasting state on a separate day. We were able to bring the fed and fasting PET volume images into spatial registration with each other and with an MR-derived atlas of the mouse brain, so that the differences in uptake between the two states could be mapped quantitatively against the neuroanatomic regions of the atlas. Our approach is suitable for studying the effects of gastric dysmotilities on central responses to feeding.

  3. 3D motion artifact compenstation in CT image with depth camera

    NASA Astrophysics Data System (ADS)

    Ko, Youngjun; Baek, Jongduk; Shim, Hyunjung

    2015-02-01

    Computed tomography (CT) is a medical imaging technology that projects computer-processed X-rays to acquire tomographic images or the slices of specific organ of body. A motion artifact caused by patient motion is a common problem in CT system and may introduce undesirable artifacts in CT images. This paper analyzes the critical problems in motion artifacts and proposes a new CT system for motion artifact compensation. We employ depth cameras to capture the patient motion and account it for the CT image reconstruction. In this way, we achieve the significant improvement in motion artifact compensation, which is not possible by previous techniques.

  4. 3D detection of colonic polyps by CT colonography: accuracy, pitfalls, and solutions by adjunct 2D workup.

    PubMed

    Schmidt, S A; Ernst, A S; Beer, M; Juchems, M S

    2015-10-01

    Computed tomography colonography (CTC) enables evaluation of the colon with minimal invasiveness. In spite of advances in multidetector CT (MDCT) technology and advanced software features, including electronic bowel cleansing (digital removal and tagging of fluid and debris), a number of potential pitfalls in the evaluation of the 3D volumetric dataset persist. The purpose of this article is to illustrate the strengths and potential pitfalls in the detection of colorectal polyps using CTC via a primary three-dimensional (3D) approach for evaluation. PMID:26220124

  5. A New CT Method for Assessing 3D Movements in Lumbar Facet Joints and Vertebrae in Patients before and after TDR

    PubMed Central

    Svedmark, Per; Berg, Svante; Noz, Marilyn E.; Maguire, Gerald Q.; Zeleznik, Michael P.; Weidenhielm, Lars; Nemeth, Gunnar; Olivecrona, Henrik

    2015-01-01

    This study describes a 3D-CT method for analyzing facet joint motion and vertebral rotation in the lumbar spine after TDR. Ten patients were examined before and then three years after surgery, each time with two CT scans: provoked flexion and provoked extension. After 3D registration, the facet joint 3D translation and segmental vertebral 3D rotation were analyzed at the operated level (L5-S1) and adjacent level (L4-L5). Pain was evaluated using VAS. The median (±SD) 3D movement in the operated level for the left facet joint was 3.2 mm (±1.9 mm) before and 3.5 mm (±1.7 mm) after surgery and for the right facet joint was 3.0 mm (±1.0 mm) before and 3.6 mm (±1.4 mm) after surgery. The median vertebral rotation in the sagittal plane at the operated level was 5.4° (±2.3°) before surgery and 6.8° (±1.7°) after surgery and in the adjacent level was 7.7° (±4.0°) before and 9.2° (±2.7°) after surgery. The median VAS was reduced from 6 (range 5–8) to 3 (range 2–8) in extension and from 4 (range 2–6) to 2 (range 1–3) in flexion. PMID:26587533

  6. Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays

    PubMed Central

    Contreras, Javier; Tornero, Josep; Ferreira, Isabel; Martins, Rodrigo; Gomes, Luis; Fortunato, Elvira

    2015-01-01

    A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. PMID:26633403

  7. Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays.

    PubMed

    Contreras, Javier; Tornero, Josep; Ferreira, Isabel; Martins, Rodrigo; Gomes, Luis; Fortunato, Elvira

    2015-01-01

    A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. PMID:26633403

  8. Self-calibration of cone-beam CT geometry using 3D-2D image registration.

    PubMed

    Ouadah, S; Stayman, J W; Gang, G J; Ehtiati, T; Siewerdsen, J H

    2016-04-01

    Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM-e.g. on the CBCT bench, FWHM  =  0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p  <  0.001). Similar improvements were measured in RPE-e.g. on the robotic C-arm, RPE  =  0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p  <  0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is

  9. Self-calibration of cone-beam CT geometry using 3D-2D image registration

    NASA Astrophysics Data System (ADS)

    Ouadah, S.; Stayman, J. W.; Gang, G. J.; Ehtiati, T.; Siewerdsen, J. H.

    2016-04-01

    Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a ‘self-calibration’ of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM—e.g. on the CBCT bench, FWHM  =  0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p  <  0.001). Similar improvements were measured in RPE—e.g. on the robotic C-arm, RPE  =  0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p  <  0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is

  10. Non-rigid registration of small animal skeletons from micro-CT using 3D shape context

    NASA Astrophysics Data System (ADS)

    Xiao, Di; Bourgeat, Pierrick; Fripp, Jurgen; Acosta Tamayo, Oscar; Gregoire, Marie Claude; Salvado, Olivier

    2009-02-01

    Small animal registration is an important step for molecular image analysis. Skeleton registration from whole-body or only partial micro Computerized Tomography (CT) image is often performed to match individual rats to atlases and templates, for example to identify organs in positron emission tomography (PET). In this paper, we extend the shape context matching technique for 3D surface registration and apply it for rat hind limb skeleton registration from CT images. Using the proposed method, after standard affine iterative closest point (ICP) registration, correspondences between the 3D points from sour and target objects were robustly found and used to deform the limb skeleton surface with thin-plate-spline (TPS). Experiments are described using phantoms and actual rat hind limb skeletons. On animals, mean square errors were decreased by the proposed registration compared to that of its initial alignment. Visually, skeletons were successfully registered even in cases of very different animal poses.

  11. Documentation and Instructions for Running Two Python Scripts that Aid in Setting up 3D Measurements using the Polytec 3D Scanning Laser Doppler Vibrometer.

    SciTech Connect

    Rohe, Daniel Peter

    2015-08-24

    Sandia National Laboratories has recently purchased a Polytec 3D Scanning Laser Doppler Vibrometer for vibration measurement. This device has proven to be a very nice tool for making vibration measurements, and has a number of advantages over traditional sensors such as accelerometers. The non-contact nature of the laser vibrometer means there is no mass loading due to measuring the response. Additionally, the laser scanning heads can position the laser spot much more quickly and accurately than placing an accelerometer or performing a roving hammer impact. The disadvantage of the system is that a significant amount of time must be invested to align the lasers with each other and the part so that the laser spots can be accurately positioned. The Polytec software includes a number of nice tools to aid in this procedure; however, certain portions are still tedious. Luckily, the Polytec software is readily extensible by programming macros for the system, so tedious portions of the procedure can be made easier by automating the process. The Polytec Software includes a WinWrap (similar to Visual Basic) editor and interface to run macros written in that programming language. The author, however, is much more proficient in Python, and the latter also has a much larger set of libraries that can be used to create very complex macros, while taking advantage of Python’s inherent readability and maintainability.

  12. A 3D metal artifact correction method in cone-beam CT bone imaging by using an implant image library

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Ning, Ruola; Conover, David

    2008-03-01

    Cone-beam CT (CBCT) technique has been used by orthopedists to monitor bone graft growth after orthopedic surgery. In order to correct severe metal artifacts in reconstructed images caused by metal implants used in bone grafting, a three-dimensional metal artifact correction method has been previously proposed. The implants' mathematic boundaries were generated to help to segment metal from reconstructed images. The segmented metal implants were forward-projected onto the detector to create metal-only projections to compensate for beam-hardening effect. This method was proved effective with the metal implants of regular shape which can be simulated by simple 3D primitives, such as cuboid, cylinder and cone. But for metal implants of arbitrary shape, their boundaries are difficult to define mathematically. To solve this problem, this paper proposed a method by setting up an implant image library and using the implants' a priori shape information from the library during the artifact correction. The implants were acquired and scanned before the surgery and their a priori information were stored in a library. During the artifact correction, the library was called to provide the shape information of the implants to help to do the implant segmentation. The segmented implants were forward-projected onto the detector to generate implant-only projections by a cone-beam forward-projection technique. Beam-hardening effect in the original projections was then compensated by high polynomial orders of implant projections. Finally, the corrected projections were back-projected to produce artifacts-reduced images. Both phantom studies and patient studies were conducted to test this correction method. Results from both studies show the artifacts have been greatly reduced and the accuracy of bone volume measurement has been increased.

  13. Clinically feasible reconstruction of 3D whole-body PET/CT data using blurred anatomical labels

    NASA Astrophysics Data System (ADS)

    Comtat, Claude; Kinahan, Paul E.; Fessler, Jeffrey A.; Beyer, Thomas; Townsend, David W.; Defrise, Michel; Michel, Christian

    2002-01-01

    We present the results of utilizing aligned anatomical information from CT images to locally adjust image smoothness during the reconstruction of three-dimensional (3D) whole-body positron emission tomography (PET) data. The ability of whole-body PET imaging to detect malignant neoplasms is becoming widely recognized. Potentially useful, however, is the role of whole-body PET in quantitative estimation of tracer uptake. The utility of PET in oncology is often limited by the high level of statistical noise in the images. Reduction in noise can be obtained by incorporating a priori image smoothness information from correlated anatomical information during the reconstruction of PET data. A combined PET/CT scanner allows the acquisition of accurately aligned PET and x-ray CT whole-body data. We use the Fourier rebinning algorithm (FORE) to accurately convert the 3D PET data to two-dimensional (2D) data to accelerate the image reconstruction process. The 2D datasets are reconstructed with successive over-relaxation of a penalized weighted least squares (PWLS) objective function to model the statistics of the acquisition, data corrections, and rebinning. A 3D voxel label model is presented that incorporates the anatomical information via the penalty weights of the PWLS objective function. This combination of FORE + PWLS + labels was developed as it allows for both reconstruction of 3D whole-body data sets in clinically feasible times and also the inclusion of anatomical information in such a way that convergence can be guaranteed. Since mismatches between anatomical (CT) and functional (PET) data are unavoidable in practice, the labels are 'blurred' to reflect the uncertainty associated with the anatomical information. Simulated and experimental results show the potential advantage of incorporating anatomical information by using blurred labels to calculate the penalty weights. We conclude that while the effect of this method on detection tasks is complicated and unclear

  14. Three-dimensional analysis of alveolar bone resorption by image processing of 3-D dental CT images

    NASA Astrophysics Data System (ADS)

    Nagao, Jiro; Kitasaka, Takayuki; Mori, Kensaku; Suenaga, Yasuhito; Yamada, Shohzoh; Naitoh, Munetaka

    2006-03-01

    We have developed a novel system that provides total support for assessment of alveolar bone resorption, caused by periodontitis, based on three-dimensional (3-D) dental CT images. In spite of the difficulty in perceiving the complex 3-D shape of resorption, dentists assessing resorption location and severity have been relying on two-dimensional radiography and probing, which merely provides one-dimensional information (depth) about resorption shape. However, there has been little work on assisting assessment of the disease by 3-D image processing and visualization techniques. This work provides quantitative evaluation results and figures for our system that measures the three-dimensional shape and spread of resorption. It has the following functions: (1) measures the depth of resorption by virtually simulating probing in the 3-D CT images, taking advantage of image processing of not suffering obstruction by teeth on the inter-proximal sides and much smaller measurement intervals than the conventional examination; (2) visualizes the disposition of the depth by movies and graphs; (3) produces a quantitative index and intuitive visual representation of the spread of resorption in the inter-radicular region in terms of area; and (4) calculates the volume of resorption as another severity index in the inter-radicular region and the region outside it. Experimental results in two cases of 3-D dental CT images and a comparison of the results with the clinical examination results and experts' measurements of the corresponding patients confirmed that the proposed system gives satisfying results, including 0.1 to 0.6mm of resorption measurement (probing) error and fairly intuitive presentation of measurement and calculation results.

  15. Stereolithographic vascular replicas from CT scans: choosing treatment strategies, teaching, and research from live patient scan data.

    PubMed

    Knox, Kimberly; Kerber, Charles W; Singel, Soren A; Bailey, Michael J; Imbesi, Steven G

    2005-01-01

    Our goal was to develop a system that would allow us to recreate live patient arterial pathology by using an industrial technique known as stereolithography (or rapid prototyping). In industry, drawings rendered into dicom files can be exported to a computer programmed to drive various industrial tools. Those tools then make a 3D structure shown by the original drawings. We manipulated CT scan dicom files to drive a stereolithography machine and were able to make replicas of the vascular diseases of three patients. PMID:15956511

  16. VIRO 3D: fast three-dimensional full-body scanning for humans and other living objects

    NASA Astrophysics Data System (ADS)

    Stein, Norbert; Minge, Bernhard

    1998-03-01

    The development of a family of partial and whole body scanners provides a complete technology for fully three-dimensional and contact-free scans on human bodies or other living objects within seconds. This paper gives insight into the design and the functional principles of the whole body scanner VIRO 3D operating on the basis of the laser split-beam method. The arrangement of up to 24 camera/laser combinations, thus dividing the area into different camera fields and an all- around sensor configuration travelling in vertical direction allow the complete 360-degree-scan of an object within 6 - 20 seconds. Due to a special calibration process the different sensors are matched and the measured data are combined. Up to 10 million 3D measuring points with a resolution of approximately 1 mm are processed in all coordinate axes to generate a 3D model. By means of high-performance processors in combination with real-time image processing chips the image data from almost any number of sensors can be recorded and evaluated synchronously in video real-time. VIRO 3D scanning systems have already been successfully implemented in various applications and will open up new perspectives in different other fields, ranging from industry, orthopaedic medicine, plastic surgery to art and photography.

  17. Algorithm of pulmonary emphysema extraction using thoracic 3-D CT images

    NASA Astrophysics Data System (ADS)

    Saita, Shinsuke; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Nakano, Yasutaka; Ohmatsu, Hironobu; Tominaga, Keigo; Eguchi, Kenji; Moriyama, Noriyuki

    2008-03-01

    Emphysema patients have the tendency to increase due to aging and smoking. Emphysematous disease destroys alveolus and to repair is impossible, thus early detection is essential. CT value of lung tissue decreases due to the destruction of lung structure. This CT value becomes lower than the normal lung- low density absorption region or referred to as Low Attenuation Area (LAA). So far, the conventional way of extracting LAA by simple thresholding has been proposed. However, the CT value of CT image fluctuates due to the measurement conditions, with various bias components such as inspiration, expiration and congestion. It is therefore necessary to consider these bias components in the extraction of LAA. We removed these bias components and we proposed LAA extraction algorithm. This algorithm has been applied to the phantom image. Then, by using the low dose CT(normal: 30 cases, obstructive lung disease: 26 cases), we extracted early stage LAA and quantitatively analyzed lung lobes using lung structure.

  18. Construction and test of an X-ray CT setup for material resolved 3D imaging with Medipix based detectors

    NASA Astrophysics Data System (ADS)

    Schioppa, Enrico, Jr.; Uher, Josef; Visser, Jan

    2012-10-01

    A prototype computerized tomography (CT) setup has been recently built at Nikhef in order to exploit the material resolved capabilities of Medipix based detectors in X-ray imaging. The CT scanner contains a Hamamatsu 90 kVp microfocus X-ray tube and an entirely remotely controllable sample alignment system. The complete setup is fully integrated with the detector operation software. Moreover the 120 frames/s RelaxD readout system [1] allows real time X-ray imaging of fast moving samples. In this work, the description of the setup is given and the first results obtained with Medipix2 [2] and Timepix [3] detectors are presented. They concern detector calibration with fluorescence lines, CT reconstruction of small biological and non-biological samples and material resolved 3D micro-imaging [4].

  19. Non-rigid registration between 3D ultrasound and CT images of the liver based on intensity and gradient information

    NASA Astrophysics Data System (ADS)

    Lee, Duhgoon; Nam, Woo Hyun; Lee, Jae Young; Ra, Jong Beom

    2011-01-01

    In order to utilize both ultrasound (US) and computed tomography (CT) images of the liver concurrently for medical applications such as diagnosis and image-guided intervention, non-rigid registration between these two types of images is an essential step, as local deformation between US and CT images exists due to the different respiratory phases involved and due to the probe pressure that occurs in US imaging. This paper introduces a voxel-based non-rigid registration algorithm between the 3D B-mode US and CT images of the liver. In the proposed algorithm, to improve the registration accuracy, we utilize the surface information of the liver and gallbladder in addition to the information of the vessels inside the liver. For an effective correlation between US and CT images, we treat those anatomical regions separately according to their characteristics in US and CT images. Based on a novel objective function using a 3D joint histogram of the intensity and gradient information, vessel-based non-rigid registration is followed by surface-based non-rigid registration in sequence, which improves the registration accuracy. The proposed algorithm is tested for ten clinical datasets and quantitative evaluations are conducted. Experimental results show that the registration error between anatomical features of US and CT images is less than 2 mm on average, even with local deformation due to different respiratory phases and probe pressure. In addition, the lesion registration error is less than 3 mm on average with a maximum of 4.5 mm that is considered acceptable for clinical applications.

  20. Fast high-resolution 3D total internal reflection fluorescence microscopy by incidence angle scanning and azimuthal averaging

    PubMed Central

    Boulanger, Jérôme; Gueudry, Charles; Münch, Daniel; Cinquin, Bertrand; Paul-Gilloteaux, Perrine; Bardin, Sabine; Guérin, Christophe; Senger, Fabrice; Blanchoin, Laurent; Salamero, Jean

    2014-01-01

    Total internal reflection fluorescence microscopy (TIRFM) is the method of choice to visualize a variety of cellular processes in particular events localized near the plasma membrane of live adherent cells. This imaging technique not relying on particular fluorescent probes provides a high sectioning capability. It is, however, restricted to a single plane. We present here a method based on a versatile design enabling fast multiwavelength azimuthal averaging and incidence angles scanning to computationally reconstruct 3D images sequences. We achieve unprecedented 50-nm axial resolution over a range of 800 nm above the coverslip. We apply this imaging modality to obtain structural and dynamical information about 3D actin architectures. We also temporally decipher distinct Rab11a-dependent exocytosis events in 3D at a rate of seven stacks per second. PMID:25404337

  1. State-of-the-art in CT hardware and scan modes for cardiovascular CT

    PubMed Central

    Halliburton, Sandra; Arbab-Zadeh, Armin; Dey, Damini; Einstein, Andrew J.; Gentry, Ralph; George, Richard T.; Gerber, Thomas; Mahesh, Mahadevappa; Weigold, Wm. Guy

    2013-01-01

    Multidetector row computed tomography (CT) allows noninvasive anatomic and functional imaging of the heart, great vessels, and the coronary arteries. In recent years, there have been several advances in CT hardware, which have expanded the clinical utility of CT for cardiovascular imaging; such advances are ongoing. This review article from the Society of Cardiovascular Computed Tomography (SCCT) Basic and Emerging Sciences and Technology (BEST) Working Group summarizes the technical aspects of current state-of-the-art CT hardware and describes the scan modes this hardware supports for cardiovascular CT imaging. PMID:22551595

  2. Structured Light Based 3d Scanning for Specular Surface by the Combination of Gray Code and Phase Shifting

    NASA Astrophysics Data System (ADS)

    Zhang, Yujia; Yilmaz, Alper

    2016-06-01

    Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i) A complete setup of the structured light based 3D scanning system; (ii) A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the advantages of our new

  3. Rigid 2D/3D registration of intraoperative digital x-ray images and preoperative CT and MR images

    NASA Astrophysics Data System (ADS)

    Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo

    2002-05-01

    This paper describes a novel approach to register 3D computed tomography (CT) or magnetic resonance (MR) images to a set of 2D X-ray images. Such a registration may be a valuable tool for intraoperative determination of the precise position and orientation of some anatomy of interest, defined in preoperative images. The registration is based solely on the information present in 2D and 3D images. It does not require fiducial markers, X-ray image segmentation, or construction of digitally reconstructed radiographs. The originality of the approach is in using normals to bone surfaces, preoperatively defined in 3D MR or CT data, and gradients of intraoperative X-ray images, which are back-projected towards the X-ray source. The registration is then concerned with finding that rigid transformation of a CT or MR volume, which provides the best match between surface normals and back projected gradients, considering their amplitudes and orientations. The method is tested on a lumbar spine phantom. Gold standard registration is obtained by fidicual markers attached to the phantom. Volumes of interest, containing single vertebrae, are registered to different pairs of X-ray images from different starting positions, chosen randomly and uniformly around the gold standard position. Target registration errors and rotation errors are in order of 0.3 mm and 0.35 degrees for the CT to X-ray registration and 1.3 mm and 1.5 degrees for MR to X-ray registration. The registration is shown to be fast and accurate.

  4. Local plate/rod descriptors of 3D trabecular bone micro-CT images from medial axis topologic analysis

    SciTech Connect

    Peyrin, Francoise; Attali, Dominique; Chappard, Christine; Benhamou, Claude Laurent

    2010-08-15

    Purpose: Trabecular bone microarchitecture is made of a complex network of plate and rod structures evolving with age and disease. The purpose of this article is to propose a new 3D local analysis method for the quantitative assessment of parameters related to the geometry of trabecular bone microarchitecture. Methods: The method is based on the topologic classification of the medial axis of the 3D image into branches, rods, and plates. Thanks to the reversibility of the medial axis, the classification is next extended to the whole 3D image. Finally, the percentages of rods and plates as well as their mean thicknesses are calculated. The method was applied both to simulated test images and 3D micro-CT images of human trabecular bone. Results: The classification of simulated phantoms made of plates and rods shows that the maximum error in the quantitative percentages of plate and rods is less than 6% and smaller than with the structure model index (SMI). Micro-CT images of human femoral bone taken in osteoporosis and early or advanced osteoarthritis were analyzed. Despite the large physiological variability, the present method avoids the underestimation of rods observed with other local methods. The relative percentages of rods and plates were not significantly different between osteoarthritis and osteoporotic groups, whereas their absolute percentages were in relation to an increase of rod and plate thicknesses in advanced osteoarthritis with also higher relative and absolute number of nodes. Conclusions: The proposed method is model-independent, robust to surface irregularities, and enables geometrical characterization of not only skeletal structures but entire 3D images. Its application provided more accurate results than the standard SMI on simple simulated phantoms, but the discrepancy observed on the advanced osteoarthritis group raises questions that will require further investigations. The systematic use of such a local method in the characterization of

  5. Study of Shortwave Spectra in Fully 3D Environment: Synergy Between Scanning Radars and Spectral Radiation Measurements

    NASA Technical Reports Server (NTRS)

    Wiscombe, Warren J.

    2012-01-01

    The main theme for our research is the understanding and closure of the surface spectral shortwave radiation problem in fully 3D cloud situations by combining the new ARM scanning radars, shortwave spectrometers, and microwave radiometers with the arsenal of radiative transfer tools developed by our group. In particular, we define first a large number of cloudy test cases spanning all 3D possibilities not just the customary uniform-overcast ones. Second, for each case, we define a "Best Estimate of Clouds That Affect Shortwave Radiation" using all relevant ARM instruments, notably the new scanning radars, and contribute this to the ARM Archive. Third, we test the ASR-signature radiative transfer model RRTMG_SW for those cases, focusing on the near-IR because of long-standing problems in this spectral region, and work with the developers to improve RRTMG_SW in order to increase its penetration into the modeling community.

  6. Dynamic CT scanning of spinal column trauma

    SciTech Connect

    Brown, B.M.; Brant-Zawadzki, M.; Cann, C.E.

    1982-12-01

    Dynamic sequential computed tomographic scanning with automatic table incrementation uses low milliampere-second technique to eliminate tube cooling delays between scanning slices and, thus, markedly shortens examination times. A total of 25 patients with spinal column trauma involving 28 levels were studied with dynamic scans and retrospectively reviewed. Dynamic studies were considerably faster than conventional spine examinations and yielded reliable diagnosis. Bone disruption and subluxation was accurately evaluated, and the use of intrathecal metrizamide in low doses allowed direct visualization of spinal cord or radicular compromise. Multiplanar image reformation was aided by the dynamic incrementation technique, since motion between slices (and the resulting misregistration artifact on image reformation) was minimized. A phantom was devised to test spatial resolution of computed tomography for objects 1-3 mm in size and disclosed minimal differences for dynamic and conventional computed tomographic techniques in resolving medium-to-high-contrast objects.

  7. Feasibility study on 3-D shape analysis of high-aspect-ratio features using through-focus scanning optical microscopy

    PubMed Central

    Attota, Ravi Kiran; Weck, Peter; Kramar, John A.; Bunday, Benjamin; Vartanian, Victor

    2016-01-01

    In-line metrologies currently used in the semiconductor industry are being challenged by the aggressive pace of device scaling and the adoption of novel device architectures. Metrology and process control of three-dimensional (3-D) high-aspect-ratio (HAR) features are becoming increasingly important and also challenging. In this paper we present a feasibility study of through-focus scanning optical microscopy (TSOM) for 3-D shape analysis of HAR features. TSOM makes use of 3-D optical data collected using a conventional optical microscope for 3-D shape analysis. Simulation results of trenches and holes down to the 11 nm node are presented. The ability of TSOM to analyze an array of HAR features or a single isolated HAR feature is also presented. This allows for the use of targets with area over 100 times smaller than that of conventional gratings, saving valuable real estate on the wafers. Indications are that the sensitivity of TSOM may match or exceed the International Technology Roadmap for Semiconductors (ITRS) measurement requirements for the next several years. Both simulations and preliminary experimental results are presented. The simplicity, lowcost, high throughput, and nanometer scale 3-D shape sensitivity of TSOM make it an attractive inspection and process monitoring solution for nanomanufacturing. PMID:27464112

  8. Feasibility study on 3-D shape analysis of high-aspect-ratio features using through-focus scanning optical microscopy.

    PubMed

    Attota, Ravi Kiran; Weck, Peter; Kramar, John A; Bunday, Benjamin; Vartanian, Victor

    2016-07-25

    In-line metrologies currently used in the semiconductor industry are being challenged by the aggressive pace of device scaling and the adoption of novel device architectures. Metrology and process control of three-dimensional (3-D) high-aspect-ratio (HAR) features are becoming increasingly important and also challenging. In this paper we present a feasibility study of through-focus scanning optical microscopy (TSOM) for 3-D shape analysis of HAR features. TSOM makes use of 3-D optical data collected using a conventional optical microscope for 3-D shape analysis. Simulation results of trenches and holes down to the 11 nm node are presented. The ability of TSOM to analyze an array of HAR features or a single isolated HAR feature is also presented. This allows for the use of targets with area over 100 times smaller than that of conventional gratings, saving valuable real estate on the wafers. Indications are that the sensitivity of TSOM may match or exceed the International Technology Roadmap for Semiconductors (ITRS) measurement requirements for the next several years. Both simulations and preliminary experimental results are presented. The simplicity, lowcost, high throughput, and nanometer scale 3-D shape sensitivity of TSOM make it an attractive inspection and process monitoring solution for nanomanufacturing. PMID:27464112

  9. Model based assessment of vestibular jawbone thickness using high frequency 3D ultrasound micro-scanning

    NASA Astrophysics Data System (ADS)

    Habor, Daniel; Neuhaus, Sarah; Vollborn, Thorsten; Wolfart, Stefan; Radermacher, Klaus; Heger, Stefan

    2013-03-01

    Endosseous implants are well-established in modern dentistry. However, without appropriate therapeutic intervention, progressive peri-implant bone loss may lead to failing implants. Conventionally, the particularly relevant vestibular jawbone thickness is monitored using radiographic 3D imaging methods. Ionizing radiation, as well as imaging artifacts caused by metallic implants and superstructures are major drawbacks of these imaging modalities. In this study, a high frequency ultrasound (HFUS) based approach to assess the vestibular jawbone thickness is being introduced. It should be emphasized that the presented method does not require ultrasound penetration of the jawbone. An in-vitro study using two porcine specimens with inserted endosseous implants has been carried out to assess the accuracy of our approach. The implant of the first specimen was equipped with a gingiva former while a polymer superstructure was mounted onto the implant of the second specimen. Ultrasound data has been acquired using a 4 degree of freedom (DOF) high frequency (<50MHz) laboratory ultrasound scanner. The ultrasound raw data has been converted to polygon meshes including the surfaces of bone, gingiva, gingiva former (first specimen) and superstructure (second specimen). The meshes are matched with a-priori acquired 3D models of the implant, the superstructure and the gingiva former using a best-fit algorithm. Finally, the vestibular peri-implant bone thickness has been assessed in the resulting 3D models. The accuracy of this approach has been evaluated by comparing the ultrasound based thickness measurement with a reference measurement acquired with an optical extra-oral 3D scanner prior to covering the specimens with gingiva. As a final result, the bone thicknesses of the two specimens were measured yielding an error of -46+/-89μm (first specimen) and 70+/-93μm (second specimen).

  10. Accurate 3d Scanning of Damaged Ancient Greek Inscriptions for Revealing Weathered Letters

    NASA Astrophysics Data System (ADS)

    Papadaki, A. I.; Agrafiotis, P.; Georgopoulos, A.; Prignitz, S.

    2015-02-01

    In this paper two non-invasive non-destructive alternative techniques to the traditional and invasive technique of squeezes are presented alongside with specialized developed processing methods, aiming to help the epigraphists to reveal and analyse weathered letters in ancient Greek inscriptions carved in masonry or marble. The resulting 3D model would serve as a detailed basis for the epigraphists to try to decipher the inscription. The data were collected by using a Structured Light scanner. The creation of the final accurate three dimensional model is a complicated procedure requiring large computation cost and human effort. It includes the collection of geometric data in limited space and time, the creation of the surface, the noise filtering and the merging of individual surfaces. The use of structured light scanners is time consuming and requires costly hardware and software. Therefore an alternative methodology for collecting 3D data of the inscriptions was also implemented for reasons of comparison. Hence, image sequences from varying distances were collected using a calibrated DSLR camera aiming to reconstruct the 3D scene through SfM techniques in order to evaluate the efficiency and the level of precision and detail of the obtained reconstructed inscriptions. Problems in the acquisition processes as well as difficulties in the alignment step and mesh optimization are also encountered. A meta-processing framework is proposed and analysed. Finally, the results of processing and analysis and the different 3D models are critically inspected and then evaluated by a specialist in terms of accuracy, quality and detail of the model and the capability of revealing damaged and "hidden" letters.

  11. High-resolution 3D OCT imaging with a MEMS scanning endoscope

    NASA Astrophysics Data System (ADS)

    Fan, Li S.; Piyawattanametha, Wibool; Wu, Ming C.; Aguirre, Aaron D.; Herz, Paul R.; Chen, Yu; Fujimoto, James G.

    2005-01-01

    Three-dimensional imaging is achieved by optical coherence tomography (OCT) integrated with a two-axis MEMS scanner to enable noninvasive volume imaging of biological tissues. The longitudinal scan is obtained by optical coherence interferometry. The transverse scan is obtained by tilting the two-axis MEMS mirror to scan the optical beam across the target. High-resolution OCT imaging has enabled in vivo observation of tissue architectural layers and differentiation of normal from tumor lesions within the human gastrointestinal tract. MEMS scanner based catheters with distal beam scanning can image with higher speed, precision, and repeatability than conventional linear scanning catheters. In this work, a 1-mm diameter MEMS scanning mirror with collimator and focusing optics is integrated into a compact 5-mm diameter package that is compatible with limited space in the endoscope. A large fill factor mirror provides high aperture over large scan angle and frequencies of hundreds of Hz in both axes. Using a broadband femtosecond laser light source, high axial image resolution of ~5 um is achieved at 1.06 um wavelength. Transverse resolution of ~ 12-um is demonstrated for cross-sectional image with the endoscope.

  12. Numerical investigation of 3-D constraint effects on brittle fracture in SE(B) and C(T) specimens

    SciTech Connect

    Nevalainen, M.; Dodds, R.H. Jr.

    1996-07-01

    This investigation employs 3-D nonlinear finite element analyses to conduct an extensive parametric evaluation of crack front stress triaxiality for deep notch SE(B) and C(T) specimens and shallow notch SE(B) specimens, with and without side grooves. Crack front conditions are characterized in terms of J-Q trajectories and the constraint scaling model for cleavage fracture toughness proposed previously by Dodds and Anderson. The 3-D computational results imply that a significantly less strict size/deformation limit, relative to the limits indicated by previous plane-strain computations, is needed to maintain small-scale yielding conditions at fracture by a stress- controlled, cleavage mechanism in deep notch SE(B) and C(T) specimens. Additional new results made available from the 3-D analyses also include revised {eta}-plastic factors for use in experimental studies to convert measured work quantities to thickness average and maximum (local) J-values over the crack front.

  13. A new method for detecting colonic polyps based on local intensity structure analysis from 3D abdominal CT images

    NASA Astrophysics Data System (ADS)

    Oda, Masahiro; Nakada, Yuichi; Kitasaka, Takayuki; Mori, Kensaku; Suenaga, Yasuhito; Takayama, Tetsuji; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi; Nawano, Shigeru

    2007-03-01

    This paper presents a new method for detecting colonic polyps from abdominal CT images based on Hessian matrix analysis. Recently, virtual colonoscopy (VC) has widely received attention as a new and less-invasive colon diagnostic method. A physician diagnoses the inside of the colon using a virtual colonoscopy system. However, since the colon has many haustra and its shape is long and convoluted, a physician has to change viewpoints and viewing directions of the virtual camera many times while diagnosing. Lesions behind haustra may be overlooked. Thus this paper proposes an automated colonic polyp detection method from 3D abdominal CT images. Colonic polyps are located on the colonic wall, and their CT values are higher than colonic lumen regions. In addition, CT values inside polyps tend to gradually increase from outward to inward (blob-like structure). We employ a blob structure enhancement filter based on the eigenvalues of a Hessian matrix to detect polyps with the above blob-shaped characteristics. For reducing FPs, we eliminate polyp candidate regions in which the maximum output value of the blob structure enhancement filter is smaller than given threshold values. Also small regions are removed from candidates. We applied the proposed method to 23 cases of abdominal CT images. Overall, 74.4% of the polyps were detected with 3.8 FPs per case.

  14. Pulmonary CT image registration and warping for tracking tissue deformation during the respiratory cycle through 3D consistent image registration

    PubMed Central

    Li, Baojun; Christensen, Gary E.; Hoffman, Eric A.; McLennan, Geoffrey; Reinhardt, Joseph M.

    2008-01-01

    Tracking lung tissues during the respiratory cycle has been a challenging task for diagnostic CT and CT-guided radiotherapy. We propose an intensity- and landmark-based image registration algorithm to perform image registration and warping of 3D pulmonary CT image data sets, based on consistency constraints and matching corresponding airway branchpoints. In this paper, we demonstrate the effectivenss and accuracy of this algorithm in tracking lung tissues by both animal and human data sets. In the animal study, the result showed a tracking accuracy of 1.9 mm between 50% functional residual capacity (FRC) and 85% total lung capacity (TLC) for 12 metal seeds implanted in the lungs of a breathing sheep under precise volume control using a pulmonary ventilator. Visual inspection of the human subject results revealed the algorithm’s potential not only in matching the global shapes, but also in registering the internal structures (e.g., oblique lobe fissures, pulmonary artery branches, etc.). These results suggest that our algorithm has significant potential for warping and tracking lung tissue deformation with applications in diagnostic CT, CT-guided radiotherapy treatment planning, and therapeutic effect evaluation. PMID:19175115

  15. Interactive lung segmentation in abnormal human and animal chest CT scans

    SciTech Connect

    Kockelkorn, Thessa T. J. P. Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

    2014-08-15

    Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

  16. CT Scanning Imaging Method Based on a Spherical Trajectory

    PubMed Central

    2016-01-01

    In industrial computed tomography (CT), the mismatch between the X-ray energy and the effective thickness makes it difficult to ensure the integrity of projection data using the traditional scanning model, because of the limitations of the object’s complex structure. So, we have developed a CT imaging method that is based on a spherical trajectory. Considering an unrestrained trajectory for iterative reconstruction, an iterative algorithm can be used to realise the CT reconstruction of a spherical trajectory for complete projection data only. Also, an inclined circle trajectory is used as an example of a spherical trajectory to illustrate the accuracy and feasibility of this new scanning method. The simulation results indicate that the new method produces superior results for a larger cone-beam angle, a limited angle and tabular objects compared with traditional circle trajectory scanning. PMID:26934744

  17. [Usefulness of CT scan in the diagnosis of pulmonary aspergilloma].

    PubMed

    Gea, J; Arán, X; Sauleda, J; Broquetas, J M; Alegret, X; Bartrina, J

    1991-05-01

    Early diagnosis and precise anatomical localization of aspergillomas are essential for an effective treatment of their complications. We have evaluated the usefulness of thorax CT scan in the fulfillment of these objectives. Nine consecutive patients were studied with a presumable diagnosis of pulmonary aspergilloma. A thorax CT scan was performed in all patients (sections every 5 to 10 mm) in lying position and with lateral mobilizations. This technique allowed to rule out as fibrotic lesions some of the images previously attributed to mycetomas by conventional X-ray. On the other hand it helped to identify small size aspergillomas, to precise their localization and to demonstrate the possible communication between the main cavity and bronchial tree. In three patients who died in the period immediately following the study an excellent correlation between CT scan and underlying pathological lesions was observed. PMID:1891635

  18. CT Scanning Imaging Method Based on a Spherical Trajectory.

    PubMed

    Chen, Ping; Han, Yan; Gui, Zhiguo

    2016-01-01

    In industrial computed tomography (CT), the mismatch between the X-ray energy and the effective thickness makes it difficult to ensure the integrity of projection data using the traditional scanning model, because of the limitations of the object's complex structure. So, we have developed a CT imaging method that is based on a spherical trajectory. Considering an unrestrained trajectory for iterative reconstruction, an iterative algorithm can be used to realise the CT reconstruction of a spherical trajectory for complete projection data only. Also, an inclined circle trajectory is used as an example of a spherical trajectory to illustrate the accuracy and feasibility of this new scanning method. The simulation results indicate that the new method produces superior results for a larger cone-beam angle, a limited angle and tabular objects compared with traditional circle trajectory scanning. PMID:26934744

  19. Continuous-scanning laser Doppler vibrometry: Extensions to arbitrary areas, multi-frequency and 3D capture

    SciTech Connect

    Weekes, B.; Ewins, D.; Acciavatti, F.

    2014-05-27

    To date, differing implementations of continuous scan laser Doppler vibrometry have been demonstrated by various academic institutions, but since the scan paths were defined using step or sine functions from function generators, the paths were typically limited to 1D line scans or 2D areas such as raster paths or Lissajous trajectories. The excitation was previously often limited to a single frequency due to the specific signal processing performed to convert the scan data into an ODS. In this paper, a configuration of continuous-scan laser Doppler vibrometry is demonstrated which permits scanning of arbitrary areas, with the benefit of allowing multi-frequency/broadband excitation. Various means of generating scan paths to inspect arbitrary areas are discussed and demonstrated. Further, full 3D vibration capture is demonstrated by the addition of a range-finding facility to the described configuration, and iteratively relocating a single scanning laser head. Here, the range-finding facility was provided by a Microsoft Kinect, an inexpensive piece of consumer electronics.

  20. Continuous-scanning laser Doppler vibrometry: Extensions to arbitrary areas, multi-frequency and 3D capture

    NASA Astrophysics Data System (ADS)

    Weekes, B.; Ewins, D.; Acciavatti, F.

    2014-05-01

    To date, differing implementations of continuous scan laser Doppler vibrometry have been demonstrated by various academic institutions, but since the scan paths were defined using step or sine functions from function generators, the paths were typically limited to 1D line scans or 2D areas such as raster paths or Lissajous trajectories. The excitation was previously often limited to a single frequency due to the specific signal processing performed to convert the scan data into an ODS. In this paper, a configuration of continuous-scan laser Doppler vibrometry is demonstrated which permits scanning of arbitrary areas, with the benefit of allowing multi-frequency/broadband excitation. Various means of generating scan paths to inspect arbitrary areas are discussed and demonstrated. Further, full 3D vibration capture is demonstrated by the addition of a range-finding facility to the described configuration, and iteratively relocating a single scanning laser head. Here, the range-finding facility was provided by a Microsoft Kinect, an inexpensive piece of consumer electronics.

  1. Geometry-based vs. intensity-based medical image registration: A comparative study on 3D CT data.

    PubMed

    Savva, Antonis D; Economopoulos, Theodore L; Matsopoulos, George K

    2016-02-01

    Spatial alignment of Computed Tomography (CT) data sets is often required in numerous medical applications and it is usually achieved by applying conventional exhaustive registration techniques, which are mainly based on the intensity of the subject data sets. Those techniques consider the full range of data points composing the data, thus negatively affecting the required processing time. Alternatively, alignment can be performed using the correspondence of extracted data points from both sets. Moreover, various geometrical characteristics of those data points can be used, instead of their chromatic properties, for uniquely characterizing each point, by forming a specific geometrical descriptor. This paper presents a comparative study reviewing variations of geometry-based, descriptor-oriented registration techniques, as well as conventional, exhaustive, intensity-based methods for aligning three-dimensional (3D) CT data pairs. In this context, three general image registration frameworks were examined: a geometry-based methodology featuring three distinct geometrical descriptors, an intensity-based methodology using three different similarity metrics, as well as the commonly used Iterative Closest Point algorithm. All techniques were applied on a total of thirty 3D CT data pairs with both known and unknown initial spatial differences. After an extensive qualitative and quantitative assessment, it was concluded that the proposed geometry-based registration framework performed similarly to the examined exhaustive registration techniques. In addition, geometry-based methods dramatically improved processing time over conventional exhaustive registration. PMID:26771247

  2. Multi-frequency, 3D ODS measurement by continuous scan laser Doppler vibrometry

    NASA Astrophysics Data System (ADS)

    Weekes, Ben; Ewins, David

    2015-06-01

    Continuous scan laser Doppler vibrometry (CSLDV) is a technique which has been described and explored in the literature for over two decades, but remains niche compared to SLDV inspection by a series of discrete-point measurements. This is in part because of the unavoidable phenomenon of laser speckle, which deteriorates signal quality when velocity data is captured from a moving spot measurement. Further, applicability of CSLDV has typically been limited to line scans and rectangular areas by the application of sine, step, or ramp functions to the scanning mirrors which control the location of the measurement laser spot. In this paper it is shown that arbitrary functions to scan any area can easily be derived from a basic calibration routine, equivalent to the calibration performed in conventional discrete-point laser vibrometry. This is extended by performing the same scan path upon a test surface from three independent locations of the laser head, and decomposing the three sets of one-dimensional deflection shapes into a single set of three-dimensional deflection shapes. The test was performed with multi-sine excitation, yielding 34 operating deflection shapes from each scan.

  3. 3D inpatient dose reconstruction from the PET-CT imaging of {sup 90}Y microspheres for metastatic cancer to the liver: Feasibility study

    SciTech Connect

    Fourkal, E.; Veltchev, I.; Lin, M.; Meyer, J.; Koren, S.; Doss, M.; Yu, J. Q.

    2013-08-15

    Purpose: The introduction of radioembolization with microspheres represents a significant step forward in the treatment of patients with metastatic disease to the liver. This technique uses semiempirical formulae based on body surface area or liver and target volumes to calculate the required total activity for a given patient. However, this treatment modality lacks extremely important information, which is the three-dimensional (3D) dose delivered by microspheres to different organs after their administration. The absence of this information dramatically limits the clinical efficacy of this modality, specifically the predictive power of the treatment. Therefore, the aim of this study is to develop a 3D dose calculation technique that is based on the PET imaging of the infused microspheres.Methods: The Fluka Monte Carlo code was used to calculate the voxel dose kernel for {sup 90}Y source with voxel size equal to that of the PET scan. The measured PET activity distribution was converted to total activity distribution for the subsequent convolution with the voxel dose kernel to obtain the 3D dose distribution. In addition, dose-volume histograms were generated to analyze the dose to the tumor and critical structures.Results: The 3D inpatient dose distribution can be reconstructed from the PET data of a patient scanned after the infusion of microspheres. A total of seven patients have been analyzed so far using the proposed reconstruction method. Four patients underwent treatment with SIR-Spheres for liver metastases from colorectal cancer and three patients were treated with Therasphere for hepatocellular cancer. A total of 14 target tumors were contoured on post-treatment PET-CT scans for dosimetric evaluation. Mean prescription activity was 1.7 GBq (range: 0.58–3.8 GBq). The resulting mean maximum measured dose to targets was 167 Gy (range: 71–311 Gy). Mean minimum dose to 70% of target (D70) was 68 Gy (range: 25–155 Gy). Mean minimum dose to 90% of target

  4. Development of a Hausdorff distance based 3D quantification technique to evaluate the CT imaging system impact on depiction of lesion morphology

    NASA Astrophysics Data System (ADS)

    Sahbaee, Pooyan; Robins, Marthony; Solomon, Justin; Samei, Ehsan

    2016-04-01

    The purpose of this study was to develop a 3D quantification technique to assess the impact of imaging system on depiction of lesion morphology. Regional Hausdorff Distance (RHD) was computed from two 3D volumes: virtual mesh models of synthetic nodules or "virtual nodules" and CT images of physical nodules or "physical nodules". The method can be described in following steps. First, the synthetic nodule was inserted into anthropomorphic Kyoto thorax phantom and scanned in a Siemens scanner (Flash). Then, nodule was segmented from the image. Second, in order to match the orientation of the nodule, the digital models of the "virtual" and "physical" nodules were both geometrically translated to the origin. Then, the "physical" was gradually rotated at incremental 10 degrees. Third, the Hausdorff Distance was calculated from each pair of "virtual" and "physical" nodules. The minimum HD value represented the most matching pair. Finally, the 3D RHD map and the distribution of RHD were computed for the matched pair. The technique was scalarized using the FWHM of the RHD distribution. The analysis was conducted for various shapes (spherical, lobular, elliptical, and speculated) of nodules. The calculated FWHM values of RHD distribution for the 8-mm spherical, lobular, elliptical, and speculated "virtual" and "physical" nodules were 0.23, 0.42, 0.33, and 0.49, respectively.

  5. Deconvolution approach for 3D scanning microscopy with helical phase engineering.

    PubMed

    Roider, Clemens; Heintzmann, Rainer; Piestun, Rafael; Jesacher, Alexander

    2016-07-11

    RESCH (refocusing after scanning using helical phase engineering) microscopy is a scanning technique using engineered point spread functions which provides volumetric information. We present a strategy for processing the collected raw data with a multi-view maximum likelihood deconvolution algorithm, which inherently comprises the resolution gain of pixel-reassignment microscopy. The method, which we term MD-RESCH (for multi-view deconvolved RESCH), achieves in our current implementation a 20% resolution advantage along all three axes compared to RESCH and confocal microscopy. Along the axial direction, the resolution is comparable to that of image scanning microscopy. However, because the method inherently reconstructs a volume from a single 2D scan, a significantly higher optical sectioning becomes directly visible to the user, which would otherwise require collecting multiple 2D scans taken at a series of axial positions. Further, we introduce the use of a single-helical detection PSF to obtain an increased post-acquisition refocusing range. We present data from numerical simulations as well as experiments to confirm the validity of our approach. PMID:27410820

  6. Digital radiographic localization for CT scanning of the larynx

    SciTech Connect

    Silverman, P.M.; Korobkin, M.; Rauch, R.F.

    1983-12-01

    Computed tomography (CT) of the larynx is the preferred method for staging laryngeal carcinoma and assessing the extent of injury from trauma. The standard method of examination consists of 5 mm contiguous scans throughout the larynx in quiet respiration. Scans are performed with the patient supine with the neck slightly extended allowing the long axis of the larynx to be perpendicular to the scanning plane. A complete examination requires scanning from the supraglottic region (level of hyoid bone) to the subglottic region (level of cricoid cartlage). In the authors' experience when this method is used, multiple scans are performed cephalad to the level of interest because no upper limit of the examination is established before transaxial scans are done. We have used the lateral digital radiograph of the neck to identify specific landmarks so that the upper and lower limets of the examination can be established before scanning.

  7. Micro-CT for the quantification of 3D voids within damaged structures

    SciTech Connect

    Patterson, Brian M; Hamilton, Christopher E; Cerreta, Ellen K; Dennis - Koller, Darcie; Bronkhorst, C. A.; Hansen, B. L.

    2011-01-26

    Micro X-ray Computed Tomography (MXCT) is widely used in the materials community to examine the internal structure of materials for voids and cracks due to damage or casting, or other defects. Most research in this area focuses on the qualitative aspect of the image, simply answering; Are there voids present? Here we present an ongoing study of the quantified incipient spall voids in Cu with different grain sizes, using a gas gun with various velocities. Data analysis packages for MXCT are just now becoming able to dimensionally measure and produce statistics on the voids-present. In order to make the size of the features in the 3D image quantifiable, the question, how many radiographs are required to render the object dimensionally accurate in 3D, must be answered. A series of data sets has been coUected, varying the number of radiographs collected in order to determine the appropriate number required.

  8. Combining population and patient-specific characteristics for prostate segmentation on 3D CT images

    NASA Astrophysics Data System (ADS)

    Ma, Ling; Guo, Rongrong; Tian, Zhiqiang; Venkataraman, Rajesh; Sarkar, Saradwata; Liu, Xiabi; Tade, Funmilayo; Schuster, David M.; Fei, Baowei

    2016-03-01

    Prostate segmentation on CT images is a challenging task. In this paper, we explore the population and patient-specific characteristics for the segmentation of the prostate on CT images. Because population learning does not consider the inter-patient variations and because patient-specific learning may not perform well for different patients, we are combining the population and patient-specific information to improve segmentation performance. Specifically, we train a population model based on the population data and train a patient-specific model based on the manual segmentation on three slice of the new patient. We compute the similarity between the two models to explore the influence of applicable population knowledge on the specific patient. By combining the patient-specific knowledge with the influence, we can capture the population and patient-specific characteristics to calculate the probability of a pixel belonging to the prostate. Finally, we smooth the prostate surface according to the prostate-density value of the pixels in the distance transform image. We conducted the leave-one-out validation experiments on a set of CT volumes from 15 patients. Manual segmentation results from a radiologist serve as the gold standard for the evaluation. Experimental results show that our method achieved an average DSC of 85.1% as compared to the manual segmentation gold standard. This method outperformed the population learning method and the patient-specific learning approach alone. The CT segmentation method can have various applications in prostate cancer diagnosis and therapy.

  9. Development of a temporal multiplexed 3D beam-scanning Lissajous trajectory microscope for rapid multimodal volumetric imaging

    NASA Astrophysics Data System (ADS)

    Newman, Justin A.; Sullivan, Shane Z.; Dinh, Janny; Sarkar, Sreya; Simpson, Garth J.

    2016-03-01

    A beam-scanning microscope is described based on a temporally multiplexed Lissajous trajectory for achieving 1 kHz frame rate 3D imaging. The microscope utilizes two fast-scan resonant mirrors to direct the optical beam on a circuitous, Lissajous trajectory through the field of view. Acquisition of two simultaneous focal planes is achieved by implementation of an optical delay line, producing a second incident beam at a different focal plane relative to the initial incident beam. High frame rates are achieved by separating the full time-domain data into shorter sub-trajectories resulting in undersampling of the field of view. A model-based image reconstruction (MBIR) 3D in-painting algorithm is utilized for interpolating the missing data to recover full images. The MBIR algorithm uses a maximum a posteriori estimation with a generalized Gaussian Markov random field prior model for image interpolation. Because images are acquired using photomultiplier tubes or photodiodes, parallelization for multi-channel imaging is straightforward. Preliminary results obtained using a Lissajous trajectory beam-scanning approach coupled with temporal multiplexing by the implementation of an optical delay line demonstrate the ability to acquire 2 distinct focal planes simultaneously at frame rates >450 Hz for full 512 × 512 images. The use of multi-channel data acquisition cards allows for simultaneous multimodal image acquisition with perfect image registry between all imaging modalities. Also discussed here is the implementation of Lissajous trajectory beam-scanning on commercially available microscope hardware.

  10. Treatment of Alzheimer Disease With CT Scans

    PubMed Central

    Moore, Eugene R.; Hosfeld, Victor D.; Nadolski, David L.

    2016-01-01

    Alzheimer disease (AD) primarily affects older adults. This neurodegenerative disorder is the most common cause of dementia and is a leading source of their morbidity and mortality. Patient care costs in the United States are about 200 billion dollars and will more than double by 2040. This case report describes the remarkable improvement in a patient with advanced AD in hospice who received 5 computed tomography scans of the brain, about 40 mGy each, over a period of 3 months. The mechanism appears to be radiation-induced upregulation of the patient’s adaptive protection systems against AD, which partially restored cognition, memory, speech, movement, and appetite. PMID:27103883

  11. Analysis of thin baked-on silicone layers by FTIR and 3D-Laser Scanning Microscopy.

    PubMed

    Funke, Stefanie; Matilainen, Julia; Nalenz, Heiko; Bechtold-Peters, Karoline; Mahler, Hanns-Christian; Friess, Wolfgang

    2015-10-01

    Pre-filled syringes (PFS) and auto-injection devices with cartridges are increasingly used for parenteral administration. To assure functionality, silicone oil is applied to the inner surface of the glass barrel. Silicone oil migration into the product can be minimized by applying a thin but sufficient layer of silicone oil emulsion followed by thermal bake-on versus spraying-on silicone oil. Silicone layers thicker than 100nm resulting from regular spray-on siliconization can be characterized using interferometric profilometers. However, the analysis of thin silicone layers generated by bake-on siliconization is more challenging. In this paper, we have evaluated Fourier transform infrared (FTIR) spectroscopy after solvent extraction and a new 3D-Laser Scanning Microscopy (3D-LSM) to overcome this challenge. A multi-step solvent extraction and subsequent FTIR spectroscopy enabled to quantify baked-on silicone levels as low as 21-325μg per 5mL cartridge. 3D-LSM was successfully established to visualize and measure baked-on silicone layers as thin as 10nm. 3D-LSM was additionally used to analyze the silicone oil distribution within cartridges at such low levels. Both methods provided new, highly valuable insights to characterize the siliconization after processing, in order to achieve functionality. PMID:26316044

  12. Semi-automated extraction and delineation of 3D roads of street scene from mobile laser scanning point clouds

    NASA Astrophysics Data System (ADS)

    Yang, Bisheng; Fang, Lina; Li, Jonathan

    2013-05-01

    Accurate 3D road information is important for applications such as road maintenance and virtual 3D modeling. Mobile laser scanning (MLS) is an efficient technique for capturing dense point clouds that can be used to construct detailed road models for large areas. This paper presents a method for extracting and delineating roads from large-scale MLS point clouds. The proposed method partitions MLS point clouds into a set of consecutive "scanning lines", which each consists of a road cross section. A moving window operator is used to filter out non-ground points line by line, and curb points are detected based on curb patterns. The detected curb points are tracked and refined so that they are both globally consistent and locally similar. To evaluate the validity of the proposed method, experiments were conducted using two types of street-scene point clouds captured by Optech's Lynx Mobile Mapper System. The completeness, correctness, and quality of the extracted roads are over 94.42%, 91.13%, and 91.3%, respectively, which proves the proposed method is a promising solution for extracting 3D roads from MLS point clouds.

  13. Design of a VLSI scan conversion processor for high-performance 3-D graphics systems

    SciTech Connect

    Huang, H.U.

    1988-01-01

    Scan-conversion processing is the bottleneck in the image generation process. To solve the problem of smooth shading and hidden surface elimination, a new processor architecture was invented which has been labeled as a scan-conversion processor architecture (SCP). The SCP is designed to perform hidden surface elimination and scan conversion for 64 pixels. The color intensities are dual-buffered so that when one buffer is being updated the other can be scanned out. Z-depth is used to perform the hidden surface elimination. The key operation performed by the SCP is the evaluation of linear functions of a form like F(X,Y) = A X + B Y + C. The computation is further simplified by using incremental addition. The z-depth buffer and the color buffers are incorporated onto the same chip. The SCP receives from its preprocessor the information for the definition of polygons and the computation of z-depth and RGB color intensities. Many copies of this processor will be used in a high-performance graphics system.

  14. Increase of Readability and Accuracy of 3d Models Using Fusion of Close Range Photogrammetry and Laser Scanning

    NASA Astrophysics Data System (ADS)

    Gašparović, M.; Malarić, I.

    2012-07-01

    The development of laser scanning technology has opened a new page in geodesy and enabled an entirely new way of presenting data. Products obtained by the method of laser scanning are used in many sciences, as well as in archaeology. It should be noted that 3D models of archaeological artefacts obtained by laser scanning are fully measurable, written in 1:1 scale and have high accuracy. On the other hand, texture and RGB values of the surface of the object obtained by a laser scanner have lower resolution and poorer radiometric characteristics in relation to the textures captured with a digital camera. Scientific research and the goal of this paper are to increase the accuracy and readability of the 3D model with textures obtained with a digital camera. Laser scanning was performed with triangulation scanner of high accuracy, Vivid 9i (Konica Minolta), while for photogrammetric recording digital camera Nikon D90 with a lens of fixed focal length 20 mm, was used. It is important to stress that a posteriori accuracy score of the global registration of point clouds in the form of the standard deviation was ± 0.136 mm while the average distance was only ± 0.080 mm. Also research has proven that the quality projection texture model increases readability. Recording of archaeological artefacts and making their photorealistic 3D model greatly contributes to archaeology as a science, accelerates processing and reconstruction of the findings. It also allows the presentation of findings to the general public, not just to the experts.

  15. An open-source, automated platform for visualizing subdural electrodes using 3D CT-MRI coregistration

    PubMed Central

    Pearce, Allison; Krish, Veena T.; Wagenaar, Joost; Chen, Weixuan; Zheng, Yuanjie; Wang, Hongzhi; Lucas, Timothy H.; Gee, James C.; Litt, Brian; Davis, Kathryn A.

    2014-01-01

    Objective Visualizing implanted subdural electrodes in 3D space can greatly aid planning, executing, and validating resection in epilepsy surgery. Coregistration software is available, but cost, complexity, insufficient accuracy or validation limit adoption. We present a fully automated open-source application, based upon a novel method using post-implant CT and post-implant MR images, for accurately visualizing intracranial electrodes in 3D space. Methods CT-MR rigid brain coregistration, MR non-rigid registration, and prior-based segmentation were carried out on 7 subjects. Post-implant CT, post-implant MR, and an external labeled atlas were then aligned in the same space. The coregistration algorithm was validated by manually marking identical anatomical landmarks on the post-implant CT and post-implant MR images. Following coregistration, distances between the center of the landmark masks on the post-implant MR and the coregistered CT images were calculated for all subjects. Algorithms were implemented in open-source software and translated into a “drag and drop” desktop application for Apple Mac OS X. Results Despite post-operative brain deformation, the method was able to automatically align intra-subject multi-modal images and segment cortical subregions so that all electrodes could be visualized on the parcellated brain. Manual marking of anatomical landmarks validated the coregistration algorithm with a mean misalignment distance of 2.87 ± 0.58 mm between the landmarks. Software was easily used by operators without prior image processing experience. Significance We demonstrate an easy to use, novel platform for accurately visualizing subdural electrodes in 3D space on a parcellated brain. We rigorously validated this method using quantitative measures. The method is unique because it involves no pre-processing, is fully automated, and freely available worldwide. A desktop application, as well as the source code, are both available for download on the

  16. Uncertainty studies of topographical measurements on steel surface corrosion by 3D scanning electron microscopy.

    PubMed

    Kang, K W; Pereda, M D; Canafoglia, M E; Bilmes, P; Llorente, C; Bonetto, R

    2012-02-01

    Pitting corrosion is a damage mechanism quite serious and dangerous in both carbon steel boiler tubes for power plants which are vital to most industries and stainless steels for orthopedic human implants whose demand, due to the increase of life expectation and rate of traffic accidents, has sharply increased. Reliable methods to characterize this kind of damage are becoming increasingly necessary, when trying to evaluate the advance of damage and to establish the best procedures for component inspection in order to determine remaining lives and failure mitigation. A study about the uncertainties on the topographies of corrosion pits from 3D SEM images, obtained at low magnifications (where errors are greater) and different stage tilt angles were carried out using an in-house software previously developed. Additionally, measurements of pit depths on biomaterial surfaces, subjected to two different surface treatments on stainless steels, were carried out. The different depth distributions observed were in agreement with electrochemical measurements. PMID:22051087

  17. Utilization of 3-D elastic transformation in the registration of chest x-ray CT and whole body PET

    SciTech Connect

    Tai, Yuan-Chuan; Hoh, C.K.; Hoffman, E.J.

    1996-12-31

    X-ray CT is widely used for detection and localization of lesions in the thorax. Whole Body PET with 18-FDG is becoming accepted for staging of cancer because of its ability to detect malignancy. Combining information from these two modalities has a significant value to improve lung cancer staging and treatment planning. Due to the non-rigid nature of the thorax and the differences in the acquisition conventions, the subject is stretched non-uniformly and the images of these two modalities requires non-rigid transformation for proper registration. Techniques to register chest x-ray CT and Whole Body PET images were developed and evaluated. Accuracy of 3-D elastic transformation was tested by phantom study. Studies on patients with lung carcinoma were used to validate the technique in localizing the 18-FDG uptake and in correlating PET to x-ray CT images. The fused images showed an accurate alignment and provided confident identification of the detailed anatomy of the CT with the functional information of the PET images.

  18. Toward acquiring comprehensive radiosurgery field commissioning data using the PRESAGE®/optical-CT 3D dosimetry system

    PubMed Central

    Clift, Corey; Thomas, Andrew; Adamovics, John; Chang, Zheng; Das, Indra; Oldham, Mark

    2010-01-01

    Achieving accurate small field dosimetry is challenging. This study investigates the utility of a radiochromic plastic PRESAGE® read with optical-CT for the acquisition of radiosurgery field commissioning data from a Novalis Tx system with a high-definition multileaf collimator (HDMLC). Total scatter factors (Sc, p), beam profiles, and penumbrae were measured for five different radiosurgery fields (5, 10, 20, 30 and 40 mm) using a commercially available optical-CT scanner (OCTOPUS, MGS Research). The percent depth dose (PDD), beam profile and penumbra of the 10 mm field were also measured using a higher resolution in-house prototype CCD-based scanner. Gafchromic EBT® film was used for independent verification. Measurements of Sc, p made with PRESAGE® and film agreed with mini-ion chamber commissioning data to within 4% for every field (range 0.2–3.6% for PRESAGE®, and 1.6–3.6% for EBT). PDD, beam profile and penumbra measurements made with the two PRESAGE®/optical-CT systems and film showed good agreement with the high-resolution diode commissioning measurements with a competitive resolution (0.5 mm pixels). The in-house prototype optical-CT scanner allowed much finer resolution compared with previous applications of PRESAGE®. The advantages of the PRESAGE® system for small field dosimetry include 3D measurements, negligible volume averaging, directional insensitivity, an absence of beam perturbations, energy and dose rate independence. PMID:20134082

  19. Metal artifacts from titanium and steel screws in CT, 1.5T and 3T MR images of the tibial Pilon: a quantitative assessment in 3D

    PubMed Central

    Radzi, Shairah; Cowin, Gary; Robinson, Mark; Pratap, Jit; Volp, Andrew; Schuetz, Michael A.

    2014-01-01

    Radiographs are commonly used to assess articular reduction of the distal tibia (pilon) fractures postoperatively, but may reveal malreductions inaccurately. While magnetic resonance imaging (MRI) and computed tomography (CT) are potential three-dimensional (3D) alternatives they generate metal-related artifacts. This study aims to quantify the artifact size from orthopaedic screws using CT, 1.5T and 3T MRI data. Three screws were inserted into one intact human cadaver ankle specimen proximal to and along the distal articular surface, then CT, 1.5T and 3T MRI scanned. Four types of screws were investigated: titanium alloy (TA), stainless steel (SS) (Ø =3.5 mm), cannulated TA (CTA) and cannulated SS (CSS) (Ø =4.0 mm, Ø empty core =2.6 mm). 3D artifact models were reconstructed using adaptive thresholding. The artifact size was measured by calculating the perpendicular distance from the central screw axis to the boundary of the artifact in four anatomical directions with respect to the distal tibia. The artifact sizes (in the order of TA, SS, CTA and CSS) from CT were 2.0, 2.6, 1.6 and 2.0 mm; from 1.5T MRI they were 3.7, 10.9, 2.9, and 9 mm; and 3T MRI they were 4.4, 15.3, 3.8, and 11.6 mm respectively. Therefore, CT can be used as long as the screws are at a safe distance of about 2 mm from the articular surface. MRI can be used if the screws are at least 3 mm away from the articular surface except for SS and CSS. Artifacts from steel screws were too large thus obstructed the pilon from being visualised in MRI. Significant differences (P<0.05) were found in the size of artifacts between all imaging modalities, screw types and material types, except 1.5T versus 3T MRI for the SS screws (P=0.063). CTA screws near the joint surface can improve postoperative assessment in CT and MRI. MRI presents a favourable non-ionising alternative when using titanium hardware. Since these factors may influence the quality of postoperative assessment, potential improvements in

  20. Metal artifacts from titanium and steel screws in CT, 1.5T and 3T MR images of the tibial Pilon: a quantitative assessment in 3D.

    PubMed

    Radzi, Shairah; Cowin, Gary; Robinson, Mark; Pratap, Jit; Volp, Andrew; Schuetz, Michael A; Schmutz, Beat

    2014-06-01

    Radiographs are commonly used to assess articular reduction of the distal tibia (pilon) fractures postoperatively, but may reveal malreductions inaccurately. While magnetic resonance imaging (MRI) and computed tomography (CT) are potential three-dimensional (3D) alternatives they generate metal-related artifacts. This study aims to quantify the artifact size from orthopaedic screws using CT, 1.5T and 3T MRI data. Three screws were inserted into one intact human cadaver ankle specimen proximal to and along the distal articular surface, then CT, 1.5T and 3T MRI scanned. Four types of screws were investigated: titanium alloy (TA), stainless steel (SS) (Ø =3.5 mm), cannulated TA (CTA) and cannulated SS (CSS) (Ø =4.0 mm, Ø empty core =2.6 mm). 3D artifact models were reconstructed using adaptive thresholding. The artifact size was measured by calculating the perpendicular distance from the central screw axis to the boundary of the artifact in four anatomical directions with respect to the distal tibia. The artifact sizes (in the order of TA, SS, CTA and CSS) from CT were 2.0, 2.6, 1.6 and 2.0 mm; from 1.5T MRI they were 3.7, 10.9, 2.9, and 9 mm; and 3T MRI they were 4.4, 15.3, 3.8, and 11.6 mm respectively. Therefore, CT can be used as long as the screws are at a safe distance of about 2 mm from the articular surface. MRI can be used if the screws are at least 3 mm away from the articular surface except for SS and CSS. Artifacts from steel screws were too large thus obstructed the pilon from being visualised in MRI. Significant differences (P<0.05) were found in the size of artifacts between all imaging modalities, screw types and material types, except 1.5T versus 3T MRI for the SS screws (P=0.063). CTA screws near the joint surface can improve postoperative assessment in CT and MRI. MRI presents a favourable non-ionising alternative when using titanium hardware. Since these factors may influence the quality of postoperative assessment, potential improvements in

  1. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues.

    PubMed

    Gignac, Paul M; Kley, Nathan J; Clarke, Julia A; Colbert, Matthew W; Morhardt, Ashley C; Cerio, Donald; Cost, Ian N; Cox, Philip G; Daza, Juan D; Early, Catherine M; Echols, M Scott; Henkelman, R Mark; Herdina, A Nele; Holliday, Casey M; Li, Zhiheng; Mahlow, Kristin; Merchant, Samer; Müller, Johannes; Orsbon, Courtney P; Paluh, Daniel J; Thies, Monte L; Tsai, Henry P; Witmer, Lawrence M

    2016-06-01

    Morphologists have historically had to rely on destructive procedures to visualize the three-dimensional (3-D) anatomy of animals. More recently, however, non-destructive techniques have come to the forefront. These include X-ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard-tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT-based research is the use of chemical agents to render visible, and differentiate between, soft-tissue structures in X-ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine-based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine-based, contrast-enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting-edge applications of diffusible iodine-based contrast-enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward. PMID:26970556

  2. 3D micro-CT analysis of void formations and push-out bonding strength of resin cements used for fiber post cementation

    PubMed Central

    2016-01-01

    PURPOSE To investigate the void parameters within the resin cements used for fiber post cementation by micro-CTCT) and regional push-out bonding strength. MATERIALS AND METHODS Twenty-one, single and round shaped roots were enlarged with a low-speed drill following by endodontic treatment. The roots were divided into three groups (n=7) and fiber posts were cemented with Maxcem Elite, Multilink N and Superbond C&B resin cements. Specimens were scanned using µCT scanner at resolution of 13.7 µm. The number, area, and volume of voids between dentin and post were evaluated. A method of analysis based on the post segmentation was used, and coronal, middle and apical thirds considered separately. After the µCT analysis, roots were embedded in epoxy resin and sectioned into 2 mm thick slices (63 sections in total). Push-out testing was performed with universal testing device at 0.5 mm/min cross-head speed. Data were analyzed with Kruskal–Wallis and Mann–Whitney U tests (α=.05). RESULTS Overall, significant differences between the resin cements and the post level were observed in the void number, area, and volume (P<.05). Super-Bond C&B showed the most void formation (44.86 ± 22.71). Multilink N showed the least void surface (3.51 ± 2.24 mm2) and volume (0.01 ± 0.01 mm3). Regional push-out bond strength of the cements was not different (P>.05). CONCLUSION µCT proved to be a powerful non-destructive 3D analysis tool for visualizing the void parameters. Multilink N had the lowest void parameters. When efficiency of all cements was evaluated, direct relationship between the post region and push-out bonding strength was not observed. PMID:27141253

  3. Digital-Particle-Image-Velocimetry (DPIV) in a scanning light-sheet: 3D starting flow around a short cylinder

    NASA Astrophysics Data System (ADS)

    Brücker, Ch.

    1995-08-01

    Scanning-Particle-Image-Velocimetry Technique (SPIV), introduced by Brücker (1992) and Brücker and Althaus (1992), offers the quantitative investigation of three-dimensional vortical structures in unsteady flows. On principle, this technique combines classical Particle-Image-Velocimetry (PIV) with volume scanning using a scanning light-sheet. In our previous studies, single scans obtained from photographic frame series were evaluated to show the instantaneous vortical structure of the respective flow phenomena. Here, continuous video recordings are processed to capture also the temporal information for the study of the set-up of 3D effects in the cylinder wake. The flow is continuously sampled in depth by the scanning light-sheet and in each of the parallel planes frame-to-frame cross-correlation of the video images (DPIV) is applied to obtain the 2D velocity field. Because the scanning frequency and repetition rate is high in comparison with the characteristic time-scale of the flow, the evaluation provides a complete time-record of the 3D flow during the starting process. With use of the continuity concept as described by Robinson and Rockwell (1993), we obtained in addition the out-of-plane component of the velocity in spanwise direction. This in view, the described technique enabled the reconstruction of the three-dimensional time-dependent velocity and vorticity field. The visualization of the dynamical behaviour of these quantities as, e.g. by video, gave a good impression of the spanwise flow showing the “tornado-like” suction effect of the starting vortices.

  4. Development, Calibration and Evaluation of a Portable and Direct Georeferenced Laser Scanning System for Kinematic 3D Mapping

    NASA Astrophysics Data System (ADS)

    Heinz, Erik; Eling, Christian; Wieland, Markus; Klingbeil, Lasse; Kuhlmann, Heiner

    2015-12-01

    In recent years, kinematic laser scanning has become increasingly popular because it offers many benefits compared to static laser scanning. The advantages include both saving of time in the georeferencing and a more favorable scanning geometry. Often mobile laser scanning systems are installed on wheeled platforms, which may not reach all parts of the object. Hence, there is an interest in the development of portable systems, which remain operational even in inaccessible areas. The development of such a portable laser scanning system is presented in this paper. It consists of a lightweight direct georeferencing unit for the position and attitude determination and a small low-cost 2D laser scanner. This setup provides advantages over existing portable systems that employ heavy and expensive 3D laser scanners in a profiling mode. A special emphasis is placed on the system calibration, i. e. the determination of the transformation between the coordinate frames of the direct georeferencing unit and the 2D laser scanner. To this end, a calibration field is used, which consists of differently orientated georeferenced planar surfaces, leading to estimates for the lever arms and boresight angles with an accuracy of mm and one-tenth of a degree. Finally, point clouds of the mobile laser scanning system are compared with georeferenced point clouds of a high-precision 3D laser scanner. Accordingly, the accuracy of the system is in the order of cm to dm. This is in good agreement with the expected accuracy, which has been derived from the error propagation of previously estimated variance components.

  5. Application of 3D laser scanning technology in historical building preservation: a case study of a Chinese temple

    NASA Astrophysics Data System (ADS)

    Chang, Yu Min; Lu, Nien Hua; Wu, Tsung Chiang

    2005-06-01

    This study applies 3D Laser scanning technology to develop a high-precision measuring system for digital survey of historical building. It outperformed other methods in obtaining abundant high-precision measuring points and computing data instantly. In this study, the Pei-tien Temple, a Chinese Taoism temple in southern Taiwan famous for its highly intricate architecture and more than 300-year history, was adopted as the target to proof the high accuracy and efficiency of this system. By using French made MENSI GS-100 Laser Scanner, numerous measuring points were precisely plotted to present the plane map, vertical map and 3D map of the property. Accuracies of 0.1-1 mm in the digital data have consistently been achieved for the historical heritage measurement.

  6. Study of 3D remote sensing system based on optical scanning holography

    NASA Astrophysics Data System (ADS)

    Zhao, Shihu; Yan, Lei

    2009-06-01

    High-precision and real-time remote sensing imaging system is an important part of remote sensing development. Holography is a method of wave front record and recovery which was presented by Dennis Gabor. As a new kind of holography techniques, Optical scanning holography (OSH) and remote sensing imaging are intended to be combined together and applied in acquisition and interference measurement of remote sensing. The key principles and applicability of OSH are studied and the mathematic relation between Fresnel Zone Plate number, numerical aperture and object distance was deduced, which are proved to be feasible for OSH to apply in large scale remote sensing. At last, a new three-dimensional reflected OSH remote sensing imaging system is designed with the combination of scanning technique to record hologram patterns of large scale remote sensing scenes. This scheme is helpful for expanding OSH technique to remote sensing in future.

  7. Nanoscale 3D cellular imaging by axial scanning transmission electron tomography

    PubMed Central

    Hohmann-Marriott, Martin F.; Sousa, Alioscka A.; Azari, Afrouz A.; Glushakova, Svetlana; Zhang, Guofeng; Zimmerberg, Joshua; Leapman, Richard D.

    2009-01-01

    Electron tomography provides three-dimensional structural information about supramolecular assemblies and organelles in a cellular context but image degradation, caused by scattering of transmitted electrons, limits applicability in specimens thicker than 300 nm. We show that scanning transmission electron tomography of 1000 nm thick samples using axial detection provides resolution comparable to conventional electron tomography. The method is demonstrated by reconstructing a human erythrocyte infected with the malaria parasite Plasmodium falciparum. PMID:19718033

  8. Full-color holographic 3D imaging system using color optical scanning holography

    NASA Astrophysics Data System (ADS)

    Kim, Hayan; Kim, You Seok; Kim, Taegeun

    2016-06-01

    We propose a full-color holographic three-dimensional imaging system that composes a recording stage, a transmission and processing stage and reconstruction stage. In recording stage, color optical scanning holography (OSH) records the complex RGB holograms of an object. In transmission and processing stage, the recorded complex RGB holograms are transmitted to the reconstruction stage after conversion to off-axis RGB holograms. In reconstruction stage, the off-axis RGB holograms are reconstructed optically.

  9. Harms of CT scanning prior to surgery for suspected appendicitis.

    PubMed

    Rogers, William; Hoffman, Jerome; Noori, Naudereh

    2015-02-01

    In this brief analysis we compare the risks and benefits of performing a CT scan to confirm appendicitis prior to surgery instead of operating based on the surgeon's clinical diagnosis. We conclude that the benefit of universal imaging is to avoid 12 unnecessary appendectomies but the cost of those 12 avoided surgeries is one cancer death due to the imaging. PMID:25429870

  10. Photo-Based 3d Scanning VS. Laser Scanning - Competitive Data Acquisition Methods for Digital Terrain Modelling of Steep Mountain Slopes

    NASA Astrophysics Data System (ADS)

    Kolecka, N.

    2011-09-01

    The paper presents how terrestrial laser scanning (TLS) and terrestrial digital photogrammetry were used to create a 3D model of a steep mountain wall. Terrestrial methods of data acquisition are the most suitable for such relief, as the most effective registration is perpendicular to the surface. First, various aspects of photo-based scanning and laser scanning were discussed. The general overview of both technologies was followed by the description of a case study of the western wall of the Kościelec Mountain (2155 m). The case study area is one of the most interesting and popular rock climbing areas in the Polish High Tatra Mts. The wall is about 300 meters high, has varied relief and some parts are overhung. Triangular irregular mesh was chosen to represent the true- 3D surface with its complicated relief. To achieve a more smooth result for visualization NURBS curves and surfaces were utilized. Both 3D models were then compared to the standard DTM of the Tatra Mountains in TIN format, obtained from aerial photographs (0.2 m ground pixel size). The results showed that both TLS and terrestrial photogrammetry had similar accuracy and level of detail and could effectively supplement very high resolution DTMs of the mountain areas.

  11. Justification of CT scans using referral guidelines for imaging.

    PubMed

    Stanescu, G; Rosca-Fartat, G; Stanescu, D

    2015-07-01

    This study analyses the efficiency of the justification of individual computed tomography (CT) procedures using the good practice guide. The conformity of the CT scans with guide's recommendations was retrospectively analysed in a paediatric emergency hospital in Romania. The involved patient doses were estimated. The results show that around one-third of the examinations were not prescribed in conformity with the guide's recommendations, but these results are affected by unclear guide provisions, discussed here. The implications of the provisions of the revised International Atomic Energy Agency's Basic Safety Standards and of the Council Directive 2013/59/EURATOM were analysed. The education and training courses for medical doctors disseminating the provisions of the good practice guide should be considered as the main support for the justification of the CT scans at the individual level. PMID:25805882

  12. Acetabular fractures: what radiologists should know and how 3D CT can aid classification.

    PubMed

    Scheinfeld, Meir H; Dym, Akiva A; Spektor, Michael; Avery, Laura L; Dym, R Joshua; Amanatullah, Derek F

    2015-01-01

    Correct recognition, description, and classification of acetabular fractures is essential for efficient patient triage and treatment. Acetabular fractures may result from high-energy trauma or low-energy trauma in the elderly. The most widely used acetabular fracture classification system among radiologists and orthopedic surgeons is the system of Judet and Letournel, which includes five elementary (or elemental) and five associated fractures. The elementary fractures are anterior wall, posterior wall, anterior column, posterior column, and transverse. The associated fractures are all combinations or partial combinations of the elementary fractures and include transverse with posterior wall, T-shaped, associated both column, anterior column or wall with posterior hemitransverse, and posterior column with posterior wall. The most unique fracture is the associated both column fracture, which completely dissociates the acetabular articular surface from the sciatic buttress. Accurate categorization of acetabular fractures is challenging because of the complex three-dimensional (3D) anatomy of the pelvis, the rarity of certain acetabular fracture variants, and confusing nomenclature. Comparing a 3D image of the fractured acetabulum with a standard diagram containing the 10 Judet and Letournel categories of acetabular fracture and using a flowchart algorithm are effective ways of arriving at the correct fracture classification. Online supplemental material is available for this article. PMID:25763739

  13. A multinational deployment of 3D laser scanning to study craniofacial dysmorphology in fetal alcohol spectrum disorders

    NASA Astrophysics Data System (ADS)

    Rogers, Jeff; Wernert, Eric; Moore, Elizabeth; Ward, Richard; Wetherill, Leah F.; Foroud, Tatiana

    2007-01-01

    Craniofacial anthropometry (the measurement and analysis of head and face dimensions) has been used to assess and describe abnormal craniofacial variation (dysmorphology) and the facial phenotype in many medical syndromes. Traditionally, anthropometry measurements have been collected by the direct application of calipers and tape measures to the subject's head and face, and can suffer from inaccuracies due to restless subjects, erroneous landmark identification, clinician variability, and other forms of human error. Three-dimensional imaging technologies promise a more effective alternative that separates the acquisition and measurement phases to reduce these variabilities while also enabling novel measurements and longitudinal analysis of subjects. Indiana University (IU) is part of an international consortium of researchers studying fetal alcohol spectrum disorders (FASD). Fetal alcohol exposure results in predictable craniofacial dysmorphologies, and anthropometry has been proven to be an effective diagnosis tool for the condition. IU is leading a project to study the use of 3D surface scanning to acquire anthropometry data in order to more accurately diagnose FASD, especially in its milder forms. This paper describes our experiences in selecting, verifying, supporting, and coordinating a set of 3D scanning systems for use in collecting facial scans and anthropometric data from around the world.

  14. Efficient and robust 3D CT image reconstruction based on total generalized variation regularization using the alternating direction method.

    PubMed

    Chen, Jianlin; Wang, Linyuan; Yan, Bin; Zhang, Hanming; Cheng, Genyang

    2015-01-01

    Iterative reconstruction algorithms for computed tomography (CT) through total variation regularization based on piecewise constant assumption can produce accurate, robust, and stable results. Nonetheless, this approach is often subject to staircase artefacts and the loss of fine details. To overcome these shortcomings, we introduce a family of novel image regularization penalties called total generalized variation (TGV) for the effective production of high-quality images from incomplete or noisy projection data for 3D reconstruction. We propose a new, fast alternating direction minimization algorithm to solve CT image reconstruction problems through TGV regularization. Based on the theory of sparse-view image reconstruction and the framework of augmented Lagrange function method, the TGV regularization term has been introduced in the computed tomography and is transformed into three independent variables of the optimization problem by introducing auxiliary variables. This new algorithm applies a local linearization and proximity technique to make the FFT-based calculation of the analytical solutions in the frequency domain feasible, thereby significantly reducing the complexity of the algorithm. Experiments with various 3D datasets corresponding to incomplete projection data demonstrate the advantage of our proposed algorithm in terms of preserving fine details and overcoming the staircase effect. The computation cost also suggests that the proposed algorithm is applicable to and is effective for CBCT imaging. Theoretical and technical optimization should be investigated carefully in terms of both computation efficiency and high resolution of this algorithm in application-oriented research. PMID:26756406

  15. Estimation of aortic valve leaflets from 3D CT images using local shape dictionaries and linear coding

    NASA Astrophysics Data System (ADS)

    Liang, Liang; Martin, Caitlin; Wang, Qian; Sun, Wei; Duncan, James

    2016-03-01

    Aortic valve (AV) disease is a significant cause of morbidity and mortality. The preferred treatment modality for severe AV disease is surgical resection and replacement of the native valve with either a mechanical or tissue prosthetic. In order to develop effective and long-lasting treatment methods, computational analyses, e.g., structural finite element (FE) and computational fluid dynamic simulations, are very effective for studying valve biomechanics. These computational analyses are based on mesh models of the aortic valve, which are usually constructed from 3D CT images though many hours of manual annotation, and therefore an automatic valve shape reconstruction method is desired. In this paper, we present a method for estimating the aortic valve shape from 3D cardiac CT images, which is represented by triangle meshes. We propose a pipeline for aortic valve shape estimation which includes novel algorithms for building local shape dictionaries and for building landmark detectors and curve detectors using local shape dictionaries. The method is evaluated on real patient image dataset using a leave-one-out approach and achieves an average accuracy of 0.69 mm. The work will facilitate automatic patient-specific computational modeling of the aortic valve.

  16. A user-friendly nano-CT image alignment and 3D reconstruction platform based on LabVIEW

    NASA Astrophysics Data System (ADS)

    Wang, Sheng-Hao; Zhang, Kai; Wang, Zhi-Li; Gao, Kun; Wu, Zhao; Zhu, Pei-Ping; Wu, Zi-Yu

    2015-01-01

    X-ray computed tomography at the nanometer scale (nano-CT) offers a wide range of applications in scientific and industrial areas. Here we describe a reliable, user-friendly, and fast software package based on LabVIEW that may allow us to perform all procedures after the acquisition of raw projection images in order to obtain the inner structure of the investigated sample. A suitable image alignment process to address misalignment problems among image series due to mechanical manufacturing errors, thermal expansion, and other external factors has been considered, together with a novel fast parallel beam 3D reconstruction procedure that was developed ad hoc to perform the tomographic reconstruction. We have obtained remarkably improved reconstruction results at the Beijing Synchrotron Radiation Facility after the image calibration, the fundamental role of this image alignment procedure was confirmed, which minimizes the unwanted blurs and additional streaking artifacts that are always present in reconstructed slices. Moreover, this nano-CT image alignment and its associated 3D reconstruction procedure are fully based on LabVIEW routines, significantly reducing the data post-processing cycle, thus making the activity of the users faster and easier during experimental runs.

  17. Reconstruction of a time-averaged midposition CT scan for radiotherapy planning of lung cancer patients using deformable registration

    SciTech Connect

    Wolthaus, J. W. H.; Sonke, J.-J.; Herk, M. van; Damen, E. M. F.

    2008-09-15

    Purpose: lower lobe lung tumors move with amplitudes of up to 2 cm due to respiration. To reduce respiration imaging artifacts in planning CT scans, 4D imaging techniques are used. Currently, we use a single (midventilation) frame of the 4D data set for clinical delineation of structures and radiotherapy planning. A single frame, however, often contains artifacts due to breathing irregularities, and is noisier than a conventional CT scan since the exposure per frame is lower. Moreover, the tumor may be displaced from the mean tumor position due to hysteresis. The aim of this work is to develop a framework for the acquisition of a good quality scan representing all scanned anatomy in the mean position by averaging transformed (deformed) CT frames, i.e., canceling out motion. A nonrigid registration method is necessary since motion varies over the lung. Methods and Materials: 4D and inspiration breath-hold (BH) CT scans were acquired for 13 patients. An iterative multiscale motion estimation technique was applied to the 4D CT scan, similar to optical flow but using image phase (gray-value transitions from bright to dark and vice versa) instead. From the (4D) deformation vector field (DVF) derived, the local mean position in the respiratory cycle was computed and the 4D DVF was modified to deform all structures of the original 4D CT scan to this mean position. A 3D midposition (MidP) CT scan was then obtained by (arithmetic or median) averaging of the deformed 4D CT scan. Image registration accuracy, tumor shape deviation with respect to the BH CT scan, and noise were determined to evaluate the image fidelity of the MidP CT scan and the performance of the technique. Results: Accuracy of the used deformable image registration method was comparable to established automated locally rigid registration and to manual landmark registration (average difference to both methods <0.5 mm for all directions) for the tumor region. From visual assessment, the registration was good

  18. Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images

    NASA Astrophysics Data System (ADS)

    Botta, F.; Mairani, A.; Hobbs, R. F.; Vergara Gil, A.; Pacilio, M.; Parodi, K.; Cremonesi, M.; Coca Pérez, M. A.; Di Dia, A.; Ferrari, M.; Guerriero, F.; Battistoni, G.; Pedroli, G.; Paganelli, G.; Torres Aroche, L. A.; Sgouros, G.

    2013-11-01

    Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 108 primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3-4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image

  19. Use of the FLUKA Monte Carlo code for 3D patient-specific dosimetry on PET-CT and SPECT-CT images*

    PubMed Central

    Botta, F; Mairani, A; Hobbs, R F; Vergara Gil, A; Pacilio, M; Parodi, K; Cremonesi, M; Coca Pérez, M A; Di Dia, A; Ferrari, M; Guerriero, F; Battistoni, G; Pedroli, G; Paganelli, G; Torres Aroche, L A; Sgouros, G

    2014-01-01

    Patient-specific absorbed dose calculation for nuclear medicine therapy is a topic of increasing interest. 3D dosimetry at the voxel level is one of the major improvements for the development of more accurate calculation techniques, as compared to the standard dosimetry at the organ level. This study aims to use the FLUKA Monte Carlo code to perform patient-specific 3D dosimetry through direct Monte Carlo simulation on PET-CT and SPECT-CT images. To this aim, dedicated routines were developed in the FLUKA environment. Two sets of simulations were performed on model and phantom images. Firstly, the correct handling of PET and SPECT images was tested under the assumption of homogeneous water medium by comparing FLUKA results with those obtained with the voxel kernel convolution method and with other Monte Carlo-based tools developed to the same purpose (the EGS-based 3D-RD software and the MCNP5-based MCID). Afterwards, the correct integration of the PET/SPECT and CT information was tested, performing direct simulations on PET/CT images for both homogeneous (water) and non-homogeneous (water with air, lung and bone inserts) phantoms. Comparison was performed with the other Monte Carlo tools performing direct simulation as well. The absorbed dose maps were compared at the voxel level. In the case of homogeneous water, by simulating 108 primary particles a 2% average difference with respect to the kernel convolution method was achieved; such difference was lower than the statistical uncertainty affecting the FLUKA results. The agreement with the other tools was within 3–4%, partially ascribable to the differences among the simulation algorithms. Including the CT-based density map, the average difference was always within 4% irrespective of the medium (water, air, bone), except for a maximum 6% value when comparing FLUKA and 3D-RD in air. The results confirmed that the routines were properly developed, opening the way for the use of FLUKA for patient-specific, image

  20. Parallel graph search: application to intraretinal layer segmentation of 3D macular OCT scans

    NASA Astrophysics Data System (ADS)

    Lee, Kyungmoo; Abràmoff, Michael D.; Garvin, Mona K.; Sonka, Milan

    2012-02-01

    Image segmentation is of paramount importance for quantitative analysis of medical image data. Recently, a 3-D graph search method which can detect globally optimal interacting surfaces with respect to the cost function of volumetric images has been introduced, and its utility demonstrated in several application areas. Although the method provides excellent segmentation accuracy, its limitation is a slow processing speed when many surfaces are simultaneously segmented in large volumetric datasets. Here, we propose a novel method of parallel graph search, which overcomes the limitation and allows the quick detection of multiple surfaces. To demonstrate the obtained performance with respect to segmentation accuracy and processing speedup, the new approach was applied to retinal optical coherence tomography (OCT) image data and compared with the performance of the former non-parallel method. Our parallel graph search methods for single and double surface detection are approximately 267 and 181 times faster than the original graph search approach in 5 macular OCT volumes (200 x 5 x 1024 voxels) acquired from the right eyes of 5 normal subjects. The resulting segmentation differences were small as demonstrated by the mean unsigned differences between the non-parallel and parallel methods of 0.0 +/- 0.0 voxels (0.0 +/- 0.0 μm) and 0.27 +/- 0.34 voxels (0.53 +/- 0.66 μm) for the single- and dual-surface approaches, respectively.

  1. Morphologic 3D scanning of fallopian tubes to assist ovarian cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Madore, Wendy-Julie; De Montigny, Etienne; Deschênes, Andréanne; Benboujja, Fouzi; Leduc, Mikael; Mes-Masson, Anne-Marie; Provencher, Diane M.; Rahimi, Kurosh; Boudoux, Caroline; Godbout, Nicolas

    2016-02-01

    Pathological evaluation of the fallopian tubes is an important diagnostic result but tumors can be missed using routine approaches. As the majority of high-grade serous ovarian cancers are now believed to originate in the fallopian tubes, pathological examination should include in a thorough examination of the excised ovaries and fallopian tubes. We present an dedicated imaging system for diagnostic exploration of human fallopian tubes. This system is based on optical coherence tomography (OCT), a laser imaging modality giving access to sub- epithelial tissue architecture. This system produces cross-sectional images up to 3 mm in depth, with a lateral resolution of ≍15μm and an axial resolution of ≍12μm. An endoscopic single fiber probe was developed to fit in a human fallopian tube. This 1.2 mm probe produces 3D volume data of the entire inner tube within a few minutes. To demonstrate the clinical potential of OCT for lesion identification, we studied 5 different ovarian lesions and healthy fallopian tubes. We imaged 52 paraffin-embedded human surgical specimens with a benchtop system and compared these images with histology slides. We also imaged and compared healthy oviducts from 3 animal models to find one resembling the human anatomy and to develop a functional ex vivo imaging procedure with the endoscopic probe. We also present an update on an ongoing clinical pilot study on women undergoing prophylactic or diagnostic surgery in which we image ex vivo fallopian tubes with the endoscopic probe.

  2. Foot roll-over evaluation based on 3D dynamic foot scan.

    PubMed

    Samson, William; Van Hamme, Angèle; Sanchez, Stéphane; Chèze, Laurence; Van Sint Jan, Serge; Feipel, Véronique

    2014-01-01

    Foot roll-over is commonly analyzed to evaluate gait pathologies. The current study utilized a dynamic foot scanner (DFS) to analyze foot roll-over. The right feet of ten healthy subjects were assessed during gait trials with a DFS system integrated into a walkway. A foot sole picture was computed by vertically projecting points from the 3D foot shape which were lower than a threshold height of 15 mm. A 'height' value of these projected points was determined; corresponding to the initial vertical coordinates prior to projection. Similar to pedobarographic analysis, the foot sole picture was segmented into anatomical regions of interest (ROIs) to process mean height (average of height data by ROI) and projected surface (area of the projected foot sole by ROI). Results showed that these variables evolved differently to plantar pressure data previously reported in the literature, mainly due to the specificity of each physical quantity (millimeters vs Pascals). Compared to plantar pressure data arising from surface contact by the foot, the current method takes into account the whole plantar aspect of the foot, including the parts that do not make contact with the support surface. The current approach using height data could contribute to a better understanding of specific aspects of foot motion during walking, such as plantar arch height and the windlass mechanism. Results of this study show the underlying method is reliable. Further investigation is required to validate the DFS measurements within a clinical context, prior to implementation into clinical practice. PMID:24119779

  3. Reproducibilty test of ferrous xylenol orange gel dose response with optical cone beam CT scanning

    NASA Astrophysics Data System (ADS)

    Jordan, K.; Battista, J.

    2004-01-01

    Our previous studies of ferrous xylenol orange gelatin gel have revealed a spatial dependence to the dose response of samples contained in 10 cm diameter cylinders. Dose response is defined as change in optical attenuation coefficient divided by the dose (units cm-1 Gy-1). This set of experiments was conducted to determine the reproducibility of our preparation, irradiation and full 3D optical cone beam CT scanning. The data provided an internal check of a larger storage time-dose response dependence study.

  4. Development of Kinematic 3D Laser Scanning System for Indoor Mapping and As-Built BIM Using Constrained SLAM

    PubMed Central

    Jung, Jaehoon; Yoon, Sanghyun; Ju, Sungha; Heo, Joon

    2015-01-01

    The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM). The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM) technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m) according to the guidelines of the General Services Administration for BIM accuracy. PMID:26501292

  5. Development of kinematic 3D laser scanning system for indoor mapping and as-built BIM using constrained SLAM.

    PubMed

    Jung, Jaehoon; Yoon, Sanghyun; Ju, Sungha; Heo, Joon

    2015-01-01

    The growing interest and use of indoor mapping is driving a demand for improved data-acquisition facility, efficiency and productivity in the era of the Building Information Model (BIM). The conventional static laser scanning method suffers from some limitations on its operability in complex indoor environments, due to the presence of occlusions. Full scanning of indoor spaces without loss of information requires that surveyors change the scanner position many times, which incurs extra work for registration of each scanned point cloud. Alternatively, a kinematic 3D laser scanning system, proposed herein, uses line-feature-based Simultaneous Localization and Mapping (SLAM) technique for continuous mapping. Moreover, to reduce the uncertainty of line-feature extraction, we incorporated constrained adjustment based on an assumption made with respect to typical indoor environments: that the main structures are formed of parallel or orthogonal line features. The superiority of the proposed constrained adjustment is its reduction for uncertainties of the adjusted lines, leading to successful data association process. In the present study, kinematic scanning with and without constrained adjustment were comparatively evaluated in two test sites, and the results confirmed the effectiveness of the proposed system. The accuracy of the 3D mapping result was additionally evaluated by comparison with the reference points acquired by a total station: the Euclidean average distance error was 0.034 m for the seminar room and 0.043 m for the corridor, which satisfied the error tolerance for point cloud acquisition (0.051 m) according to the guidelines of the General Services Administration for BIM accuracy. PMID:26501292

  6. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    PubMed

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

  7. Scanning all-fiber-optic endomicroscopy system for 3D nonlinear optical imaging of biological tissues

    PubMed Central

    Wu, Yicong; Leng, Yuxin; Xi, Jiefeng; Li, Xingde

    2009-01-01

    An extremely compact all-fiber-optic scanning endomicroscopy system was developed for two-photon fluorescence (TPF) and second harmonic generation (SHG) imaging of biological samples. A conventional double-clad fiber (DCF) was employed in the endomicroscope for single-mode femtosecond pulse delivery, multimode nonlinear optical signals collection and fast two-dimensional scanning. A single photonic bandgap fiber (PBF) with negative group velocity dispersion at two-photon excitation wavelength (i.e. ~810 nm) was used for pulse prechirping in replacement of a bulky grating/lens-based pulse stretcher. The combined use of DCF and PBF in the endomicroscopy system made the endomicroscope basically a plug-and-play unit. The excellent imaging ability of the extremely compact all-fiber-optic nonlinear optical endomicroscopy system was demonstrated by SHG imaging of rat tail tendon and depth-resolved TPF imaging of epithelial tissues stained with acridine orange. The preliminary results suggested the promising potential of this extremely compact all-fiber-optic endomicroscopy system for real-time assessment of both epithelial and stromal structures in luminal organs. PMID:19434122

  8. Correcting for 3D distortion when using backscattered electron detectors in a scanning electron microscope.

    PubMed

    Proctor, Jacob M

    2009-01-01

    A variable pressure scanning electron microscope (VPSEM) can produce a topographic surface relief of a physical object under examination, in addition to its two-dimensional (2D) image. This topographic surface relief is especially helpful when dealing with porous rock because it may elucidate the pore-space structure as well as grain shape and size. Whether the image accurately reproduces the physical object depends on the management of the hardware, acquisition, and postprocessing. Two problems become apparent during testing: (a) a topographic surface relief of a precision ball bearing is distorted and does not correspond to the physical dimensions of the actual sphere and (b) an image of a topographic surface relief of a Berea sandstone is geometrically tilted and topographically distorted even after standard corrections are applied. The procedure presented here is to ensure the veracity of the image, and includes: (a) adjusting the brightness and contrast levels originally provided by the manufacturer and (b) tuning the amplifiers of the backscatter detector plates to be equal to each other, and producing zero voltage when VPSEM is idle. This procedure is tested and verified on the said two physical samples. SCANNING 31: 59-64, 2009. (c) 2009 Wiley Periodicals, Inc. PMID:19204999

  9. Geodesic Distance Algorithm for Extracting the Ascending Aorta from 3D CT Images

    PubMed Central

    Jang, Yeonggul; Jung, Ho Yub; Hong, Youngtaek; Cho, Iksung; Shim, Hackjoon; Chang, Hyuk-Jae

    2016-01-01

    This paper presents a method for the automatic 3D segmentation of the ascending aorta from coronary computed tomography angiography (CCTA). The segmentation is performed in three steps. First, the initial seed points are selected by minimizing a newly proposed energy function across the Hough circles. Second, the ascending aorta is segmented by geodesic distance transformation. Third, the seed points are effectively transferred through the next axial slice by a novel transfer function. Experiments are performed using a database composed of 10 patients' CCTA images. For the experiment, the ground truths are annotated manually on the axial image slices by a medical expert. A comparative evaluation with state-of-the-art commercial aorta segmentation algorithms shows that our approach is computationally more efficient and accurate under the DSC (Dice Similarity Coefficient) measurements. PMID:26904151

  10. 3D-Laser-Scanning Technique Applied to Bulk Density Measurements of Apollo Lunar Samples

    NASA Technical Reports Server (NTRS)

    Macke, R. J.; Kent, J. J.; Kiefer, W. S.; Britt, D. T.

    2015-01-01

    In order to better interpret gravimetric data from orbiters such as GRAIL and LRO to understand the subsurface composition and structure of the lunar crust, it is import to have a reliable database of the density and porosity of lunar materials. To this end, we have been surveying these physical properties in both lunar meteorites and Apollo lunar samples. To measure porosity, both grain density and bulk density are required. For bulk density, our group has historically utilized sub-mm bead immersion techniques extensively, though several factors have made this technique problematic for our work with Apollo samples. Samples allocated for measurement are often smaller than optimal for the technique, leading to large error bars. Also, for some samples we were required to use pure alumina beads instead of our usual glass beads. The alumina beads were subject to undesirable static effects, producing unreliable results. Other investigators have tested the use of 3d laser scanners on meteorites for measuring bulk volumes. Early work, though promising, was plagued with difficulties including poor response on dark or reflective surfaces, difficulty reproducing sharp edges, and large processing time for producing shape models. Due to progress in technology, however, laser scanners have improved considerably in recent years. We tested this technique on 27 lunar samples in the Apollo collection using a scanner at NASA Johnson Space Center. We found it to be reliable and more precise than beads, with the added benefit that it involves no direct contact with the sample, enabling the study of particularly friable samples for which bead immersion is not possible

  11. Multitemporal 3D data capturing and GIS analysis of fluvial processes and geomorphological changes with terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Hämmerle, Martin; Forbriger, Markus; Höfle, Bernhard

    2013-04-01

    LiDAR is a state of the art method for directly capturing 3D geodata. A laser beam is emitted in a known direction. The time of flight of the laser pulse is recorded and transformed into the distance between sensor and scanned object. The result of the scanning process is a 3D laser point cloud densely covering the surveyed area. LiDAR is used in a vast variety of research fields. In this study, the focus is on the application of terrestrial laser scanning (TLS), the static and ground-based LiDAR operation, in a multitemporal analysis of fluvial geomorphology. Within the framework of two study projects in 2011/2012, two TLS surveys were carried out. The surveys covered a gravel bar of about 150 m × 25 m size in a side branch of the Neckar River near Heidelberg (49°28'36''N, 8°34'32''E) located in a nature reserve with natural river characteristics. The first survey was performed in November 2011, the second in June 2012. Due to seasonally changing water levels, the gravel bar was flooded and the morphology changed. For the field campaigns, a Riegl VZ-400 was available. Height control points and tie points for registration and georeferencing were obtained with a total station and GPS equipment. The first survey was done from 6 scan positions (77 million points) and the second from 5 positions (89 million points). The point spacing for each single scan was set to 3 mm at 10 m distance. Co-registration of the individual campaigns was done via an Iterative Closest Point algorithm. Thereafter, co-registration and fine georeferencing of both epochs was performed using manually selected tie points and least-squares adjustment. After filtering of vegetation in the 3D point cloud in the software OPALS, a digital terrain model (DTM) with 0.25 m by 0.25 m cell size was generated for each epoch. A difference raster model of the two DTMs for assessing the changes was derived excluding water surface areas using the signal amplitude recorded for each echo. From the mean

  12. Parallel deconvolution of large 3D images obtained by confocal laser scanning microscopy.

    PubMed

    Pawliczek, Piotr; Romanowska-Pawliczek, Anna; Soltys, Zbigniew

    2010-03-01

    Various deconvolution algorithms are often used for restoration of digital images. Image deconvolution is especially needed for the correction of three-dimensional images obtained by confocal laser scanning microscopy. Such images suffer from distortions, particularly in the Z dimension. As a result, reliable automatic segmentation of these images may be difficult or even impossible. Effective deconvolution algorithms are memory-intensive and time-consuming. In this work, we propose a parallel version of the well-known Richardson-Lucy deconvolution algorithm developed for a system with distributed memory and implemented with the use of Message Passing Interface (MPI). It enables significantly more rapid deconvolution of two-dimensional and three-dimensional images by efficiently splitting the computation across multiple computers. The implementation of this algorithm can be used on professional clusters provided by computing centers as well as on simple networks of ordinary PC machines. PMID:19725070

  13. See-Through Imaging of Laser-Scanned 3d Cultural Heritage Objects Based on Stochastic Rendering of Large-Scale Point Clouds

    NASA Astrophysics Data System (ADS)

    Tanaka, S.; Hasegawa, K.; Okamoto, N.; Umegaki, R.; Wang, S.; Uemura, M.; Okamoto, A.; Koyamada, K.

    2016-06-01

    We propose a method for the precise 3D see-through imaging, or transparent visualization, of the large-scale and complex point clouds acquired via the laser scanning of 3D cultural heritage objects. Our method is based on a stochastic algorithm and directly uses the 3D points, which are acquired using a laser scanner, as the rendering primitives. This method achieves the correct depth feel without requiring depth sorting of the rendering primitives along the line of sight. Eliminating this need allows us to avoid long computation times when creating natural and precise 3D see-through views of laser-scanned cultural heritage objects. The opacity of each laser-scanned object is also flexibly controllable. For a laser-scanned point cloud consisting of more than 107 or 108 3D points, the pre-processing requires only a few minutes, and the rendering can be executed at interactive frame rates. Our method enables the creation of cumulative 3D see-through images of time-series laser-scanned data. It also offers the possibility of fused visualization for observing a laser-scanned object behind a transparent high-quality photographic image placed in the 3D scene. We demonstrate the effectiveness of our method by applying it to festival floats of high cultural value. These festival floats have complex outer and inner 3D structures and are suitable for see-through imaging.

  14. Body mass estimations for Plateosaurus engelhardti using laser scanning and 3D reconstruction methods

    NASA Astrophysics Data System (ADS)

    Gunga, Hanns-Christian; Suthau, Tim; Bellmann, Anke; Friedrich, Andreas; Schwanebeck, Thomas; Stoinski, Stefan; Trippel, Tobias; Kirsch, Karl; Hellwich, Olaf

    2007-08-01

    Both body mass and surface area are factors determining the essence of any living organism. This should also hold true for an extinct organism such as a dinosaur. The present report discusses the use of a new 3D laser scanner method to establish body masses and surface areas of an Asian elephant (Zoological Museum of Copenhagen, Denmark) and of Plateosaurus engelhardti, a prosauropod from the Upper Triassic, exhibited at the Paleontological Museum in Tübingen (Germany). This method was used to study the effect that slight changes in body shape had on body mass for P. engelhardti. It was established that body volumes varied between 0.79 m3 (slim version) and 1.14 m3 (robust version), resulting in a presumable body mass of 630 and 912 kg, respectively. The total body surface areas ranged between 8.8 and 10.2 m2, of which, in both reconstructions of P. engelhardti, ˜33% account for the thorax area alone. The main difference between the two models is in the tail and hind limb reconstruction. The tail of the slim version has a surface area of 1.98 m2, whereas that of the robust version has a surface area of 2.73 m2. The body volumes calculated for the slim version were as follows: head 0.006 m3, neck 0.016 m3, fore limbs 0.020 m3, hind limbs 0.08 m3, thoracic cavity 0.533 m3, and tail 0.136 m3. For the robust model, the following volumes were established: 0.01 m3 head, neck 0.026 m3, fore limbs 0.025 m3, hind limbs 0.18 m3, thoracic cavity 0.616 m3, and finally, tail 0.28 m3. Based on these body volumes, scaling equations were used to assess the size that the organs of this extinct dinosaur have.

  15. Incorporation of 3-D Scanning Lidar Data into Google Earth for Real-time Air Pollution Observation

    NASA Astrophysics Data System (ADS)

    Chiang, C.; Nee, J.; Das, S.; Sun, S.; Hsu, Y.; Chiang, H.; Chen, S.; Lin, P.; Chu, J.; Su, C.; Lee, W.; Su, L.; Chen, C.

    2011-12-01

    3-D Differential Absorption Scanning Lidar (DIASL) system has been designed with small size, light weight, and suitable for installation in various vehicles and places for monitoring of air pollutants and displays a detailed real-time temporal and spatial variability of trace gases via the Google Earth. The fast scanning techniques and visual information can rapidly identify the locations and sources of the polluted gases and assess the most affected areas. It is helpful for Environmental Protection Agency (EPA) to protect the people's health and abate the air pollution as quickly as possible. The distributions of the atmospheric pollutants and their relationship with local metrological parameters measured with ground based instruments will also be discussed. Details will be presented in the upcoming symposium.

  16. Characterizing microscale aluminum composite layer properties on silicon solar cells with hybrid 3D scanning force measurements

    PubMed Central

    Bae, Sung-Kuk; Choi, Beomjoon; Chung, Haseung; Shin, Seungwon; Song, Hee-eun; Seo, Jung Hwan

    2016-01-01

    This article presents a novel technique to estimate the mechanical properties of the aluminum composite layer on silicon solar cells by using a hybrid 3-dimensional laser scanning force measurement (3-D LSFM) system. The 3-D LSFM system measures the material properties of sub-layers constituting a solar cell. This measurement is critical for realizing high-efficient ultra-thin solar cells. The screen-printed aluminum layer, which significantly affects the bowing phenomenon, is separated from the complete solar cell by removing the silicon (Si) layer with deep reactive ion etching. An elastic modulus of ~15.1 GPa and a yield strength of ~35.0 MPa for the aluminum (Al) composite layer were obtained by the 3-D LSFM system. In experiments performed for 6-inch Si solar cells, the bowing distances decreased from 12.02 to 1.18 mm while the Si layer thicknesses increased from 90 to 190 μm. These results are in excellent agreement with the theoretical predictions for ultra-thin Si thickness (90 μm) based on the obtained Al composite layer properties. PMID:26948248

  17. Characterizing microscale aluminum composite layer properties on silicon solar cells with hybrid 3D scanning force measurements

    NASA Astrophysics Data System (ADS)

    Bae, Sung-Kuk; Choi, Beomjoon; Chung, Haseung; Shin, Seungwon; Song, Hee-Eun; Seo, Jung Hwan

    2016-03-01

    This article presents a novel technique to estimate the mechanical properties of the aluminum composite layer on silicon solar cells by using a hybrid 3-dimensional laser scanning force measurement (3-D LSFM) system. The 3-D LSFM system measures the material properties of sub-layers constituting a solar cell. This measurement is critical for realizing high-efficient ultra-thin solar cells. The screen-printed aluminum layer, which significantly affects the bowing phenomenon, is separated from the complete solar cell by removing the silicon (Si) layer with deep reactive ion etching. An elastic modulus of ~15.1 GPa and a yield strength of ~35.0 MPa for the aluminum (Al) composite layer were obtained by the 3-D LSFM system. In experiments performed for 6-inch Si solar cells, the bowing distances decreased from 12.02 to 1.18 mm while the Si layer thicknesses increased from 90 to 190 μm. These results are in excellent agreement with the theoretical predictions for ultra-thin Si thickness (90 μm) based on the obtained Al composite layer properties.

  18. Measuring surface topography with scanning electron microscopy. I. EZEImage: a program to obtain 3D surface data.

    PubMed

    Ponz, Ezequiel; Ladaga, Juan Luis; Bonetto, Rita Dominga

    2006-04-01

    Scanning electron microscopy (SEM) is widely used in the science of materials and different parameters were developed to characterize the surface roughness. In a previous work, we studied the surface topography with fractal dimension at low scale and two parameters at high scale by using the variogram, that is, variance vs. step log-log graph, of a SEM image. Those studies were carried out with the FERImage program, previously developed by us. To verify the previously accepted hypothesis by working with only an image, it is indispensable to have reliable three-dimensional (3D) surface data. In this work, a new program (EZEImage) to characterize 3D surface topography in SEM has been developed. It uses fast cross correlation and dynamic programming to obtain reliable dense height maps in a few seconds which can be displayed as an image where each gray level represents a height value. This image can be used for the FERImage program or any other software to obtain surface topography characteristics. EZEImage also generates anaglyph images as well as characterizes 3D surface topography by means of a parameter set to describe amplitude properties and three functional indices for characterizing bearing and fluid properties. PMID:17481354

  19. Characterizing microscale aluminum composite layer properties on silicon solar cells with hybrid 3D scanning force measurements.

    PubMed

    Bae, Sung-Kuk; Choi, Beomjoon; Chung, Haseung; Shin, Seungwon; Song, Hee-Eun; Seo, Jung Hwan

    2016-01-01

    This article presents a novel technique to estimate the mechanical properties of the aluminum composite layer on silicon solar cells by using a hybrid 3-dimensional laser scanning force measurement (3-D LSFM) system. The 3-D LSFM system measures the material properties of sub-layers constituting a solar cell. This measurement is critical for realizing high-efficient ultra-thin solar cells. The screen-printed aluminum layer, which significantly affects the bowing phenomenon, is separated from the complete solar cell by removing the silicon (Si) layer with deep reactive ion etching. An elastic modulus of ~15.1 GPa and a yield strength of ~35.0 MPa for the aluminum (Al) composite layer were obtained by the 3-D LSFM system. In experiments performed for 6-inch Si solar cells, the bowing distances decreased from 12.02 to 1.18 mm while the Si layer thicknesses increased from 90 to 190 μm. These results are in excellent agreement with the theoretical predictions for ultra-thin Si thickness (90 μm) based on the obtained Al composite layer properties. PMID:26948248

  20. Adaptive model based pulmonary artery segmentation in 3D chest CT

    NASA Astrophysics Data System (ADS)

    Feuerstein, Marco; Kitasaka, Takayuki; Mori, Kensaku

    2010-03-01

    The extraction and analysis of the pulmonary artery in computed tomography (CT) of the chest can be an important, but time-consuming step for the diagnosis and treatment of lung disease, in particular in non-contrast data, where the pulmonary artery has low contrast and frequently merges with adjacent tissue of similar intensity. We here present a new method for the automatic segmentation of the pulmonary artery based on an adaptive model, Hough and Euclidean distance transforms, and spline fitting, which works equally well on non-contrast and contrast enhanced data. An evaluation on 40 patient data sets and a comparison to manual segmentations in terms of Jaccard index, sensitivity, specificity, and minimum mean distance shows its overall robustness.

  1. Estimation of vocal fold plane in 3D CT images for diagnosis of vocal fold abnormalities.

    PubMed

    Hewavitharanage, Sajini; Gubbi, Jayavardhana; Thyagarajan, Dominic; Lau, Ken; Palaniswami, Marimuthu

    2015-01-01

    Vocal folds are the key body structures that are responsible for phonation and regulating air movement into and out of lungs. Various vocal fold disorders may seriously impact the quality of life. When diagnosing vocal fold disorders, CT of the neck is the commonly used imaging method. However, vocal folds do not align with the normal axial plane of a neck and the plane containing vocal cords and arytenoids does vary during phonation. It is therefore important to generate an algorithm for detecting the actual plane containing vocal folds. In this paper, we propose a method to automatically estimate the vocal fold plane using vertebral column and anterior commissure localization. Gray-level thresholding, connected component analysis, rule based segmentation and unsupervised k-means clustering were used in the proposed algorithm. The anterior commissure segmentation method achieved an accuracy of 85%, a good estimate of the expert assessment. PMID:26736949

  2. 3D chemical mapping: application of scanning transmission (soft) X-ray microscopy (STXM) in combination with angle-scan tomography in bio-, geo-, and environmental sciences.

    PubMed

    Obst, Martin; Schmid, Gregor

    2014-01-01

    The identification of environmental processes and mechanisms often requires information on the organochemical and inorganic composition of specimens at high spatial resolution. X-ray spectroscopy (XAS) performed in the soft X-ray range (100-2,200 eV) provides chemical speciation information for elements that are of high biogeochemical relevance such as carbon, nitrogen, and oxygen but also includes transition metals such as iron, manganese, or nickel. Synchrotron-based scanning transmission X-ray microscopy (STXM) combines XAS with high resolution mapping on the 20-nm scale. This provides two-dimensional (2D) quantitative information about the distribution of chemical species such as organic macromolecules, metals, or mineral phases within environmental samples. Furthermore, the combination of STXM with angle-scan tomography allows for three-dimensional (3D) spectromicroscopic analysis of bio-, geo-, or environmental samples. For the acquisition of STXM tomography data, the sample is rotated around an axis perpendicular to the X-ray beam. Various sample preparation approaches such as stripes cut from TEM grids or the preparation of wet cells allow for preparing environmentally relevant specimens in a dry or in a fully hydrated state for 2D and 3D STXM measurements. In this chapter we give a short overview about the principles of STXM, its application to environmental sciences, different preparation techniques, and the analysis and 3D reconstruction of STXM tomography data. PMID:24357389

  3. Compact 3D lidar based on optically coupled horizontal and vertical scanning mechanism for the autonomous navigation of robots

    NASA Astrophysics Data System (ADS)

    Lee, Min-Gu; Baeg, Seung-Ho; Lee, Ki-Min; Lee, Hae-Seok; Baeg, Moon-Hong; Park, Jong-Ok; Kim, Hong-Ki

    2011-06-01

    The purpose of this research is to develop a new 3D LIDAR sensor, named KIDAR-B25, for measuring 3D image information with high range accuracy, high speed and compact size. To measure a distance to the target object, we developed a range measurement unit, which is implemented by the direct Time-Of-Flight (TOF) method using TDC chip, a pulsed laser transmitter as an illumination source (pulse width: 10 ns, wavelength: 905 nm, repetition rate: 30kHz, peak power: 20W), and an Si APD receiver, which has high sensitivity and wide bandwidth. Also, we devised a horizontal and vertical scanning mechanism, climbing in a spiral and coupled with the laser optical path. Besides, control electronics such as the motor controller, the signal processing unit, the power distributor and so on, are developed and integrated in a compact assembly. The key point of the 3D LIDAR design proposed in this paper is to use the compact scanning mechanism, which is coupled with optical module horizontally and vertically. This KIDAR-B25 has the same beam propagation axis for emitting pulse laser and receiving reflected one with no optical interference each other. The scanning performance of the KIDAR-B25 has proven with the stable operation up to 20Hz (vertical), 40Hz (horizontal) and the time is about 1.7s to reach the maximum speed. The range of vertical plane can be available up to +/-10 degree FOV (Field Of View) with a 0.25 degree angular resolution. The whole horizontal plane (360 degree) can be also available with 0.125 degree angular resolution. Since the KIDAR-B25 sensor has been planned and developed to be used in mobile robots for navigation, we conducted an outdoor test for evaluating its performance. The experimental results show that the captured 3D imaging data can be usefully applicable to the navigation of the robot for detecting and avoiding the moving objects with real time.

  4. Automatic thermographic scanning with the creation of 3D panoramic views of buildings

    NASA Astrophysics Data System (ADS)

    Ferrarini, G.; Cadelano, G.; Bortolin, A.

    2016-05-01

    Infrared thermography is widely applied to the inspection of building, enabling the identification of thermal anomalies due to the presence of hidden structures, air leakages, and moisture. One of the main advantages of this technique is the possibility to acquire rapidly a temperature map of a surface. However, due to the actual low-resolution of thermal camera and the necessity of scanning surfaces with different orientation, during a building survey it is necessary to take multiple images. In this work a device based on quantitative infrared thermography, called aIRview, has been applied during building surveys to automatically acquire thermograms with a camera mounted on a robotized pan tilt unit. The goal is to perform a first rapid survey of the building that could give useful information for the successive quantitative thermal investigations. For each data acquisition, the instrument covers a rotational field of view of 360° around the vertical axis and up to 180° around the horizontal one. The obtained images have been processed in order to create a full equirectangular projection of the ambient. For this reason the images have been integrated into a web visualization tool, working with web panorama viewers such as Google Street View, creating a webpage where it is possible to have a three dimensional virtual visit of the building. The thermographic data are embedded with the visual imaging and with other sensor data, facilitating the understanding of the physical phenomena underlying the temperature distribution.

  5. 3D imaging of biofilms on implants by detection of scattered light with a scanning laser optical tomograph

    PubMed Central

    Heidrich, Marko; Kühnel, Mark P.; Kellner, Manuela; Lorbeer, Raoul-Amadeus; Lange, Tineke; Winkel, Andreas; Stiesch, Meike; Meyer, Heiko; Heisterkamp, Alexander

    2011-01-01

    Biofilms – communities of microorganisms attached to surfaces – are a constant threat for long-term success in modern implantology. The application of laser scanning microscopy (LSM) has increased the knowledge about microscopic properties of biofilms, whereas a 3D imaging technique for the large scale visualization of bacterial growth and migration on curved and non-transparent surfaces is not realized so far. Towards this goal, we built a scanning laser optical tomography (SLOT) setup detecting scattered laser light to image biofilm on dental implant surfaces. SLOT enables the visualization of living biofilms in 3D by detecting the wavelength-dependent absorption of non-fluorescent stains like e.g. reduced triphenyltetrazolium chloride (TTC) accumulated within metabolically active bacterial cells. Thus, the presented system allows the large scale investigation of vital biofilm structure and in vitro development on cylindrical and non-transparent objects without the need for fluorescent vital staining. We suggest SLOT to be a valuable tool for the structural and volumetric investigation of biofilm formation on implants with sizes up to several millimeters. PMID:22076261

  6. Final Report – Study of Shortwave Spectra in Fully 3D Environment. Synergy Between Scanning Radars and Spectral Radiation Measurements

    SciTech Connect

    Chiu, Jui-Yuan

    2015-09-14

    ARM set out 20 years ago to “close” the radiation problem, that is, to improve radiation models to the point where they could routinely predict the observed spectral radiation fluxes knowing the optical properties of the surface and of gases, clouds and aerosols in the atmosphere. Only then could such radiation models form a proper springboard for global climate model (GCM) parameterizations of spectral radiation. Sustained efforts have more or less achieved that goal with regard to longwave radiation; ASR models now routinely predict ARM spectral longwave radiances to 1–2%. Similar efforts in the shortwave have achieved far less; the successes are mainly for carefully selected 1D stratiform cloud cases. Such cases amount, even with the most optimistic interpretation, to no more than 30% of all cases at SGP. The problem has not been lack of effort but lack of appropriate instruments.The new ARM stimulus-funded instruments, with their new capabilities, will dramatically improve this situation and once again make progress possible on the shortwave problem. The new shortwave spectrometers will provide a reliable, calibrated record including the near infrared – and for other climatic regimes than SGP. The new scanning radars will provide the 3D cloud view, making it possible to tackle fully 3D situations. Thus, our main theme for the project is the understanding and closure of the surface spectral shortwave radiation problem in fully 3D cloud situations by combining the new ARM scanning radars and shortwave spectrometers with the arsenal of radiative transfer tools.

  7. Development and verification of a novel device for dental intra-oral 3D scanning using chromatic confocal technology

    NASA Astrophysics Data System (ADS)

    Zint, M.; Stock, K.; Graser, R.; Ertl, T.; Brauer, E.; Heyninck, J.; Vanbiervliet, J.; Dhondt, S.; De Ceuninck, P.; Hibst, R.

    2015-03-01

    The presented work describes the development and verification of a novel optical, powder-free intra-oral scanner based on chromatic confocal technology combined with a multifocal approach. The proof of concept for a chromatic confocal area scanner for intra-oral scanning is given. Several prototype scanners passed a verification process showing an average accuracy (distance deviation on flat surfaces) of less than 31μm +/- 21μm and a reproducibility of less than 4μm +/- 3μm. Compared to a tactile measurement on a full jaw model fitted with 4mm ceramic spheres the measured average distance deviation between the spheres was 49μm +/- 12μm for scans of up to 8 teeth (3- unit bridge, single Quadrant) and 104μm +/- 82μm for larger scans and full jaws. The average deviation of the measured sphere diameter compared to the tactile measurement was 27μm +/- 14μm. Compared to μCT scans of plaster models equipped with human teeth the average standard deviation on up to 3 units was less than 55μm +/- 49μm whereas the reproducibility of the scans was better than 22μm +/- 10μm.

  8. Method for visualization and presentation of priceless old prints based on precise 3D scan

    NASA Astrophysics Data System (ADS)

    Bunsch, Eryk; Sitnik, Robert

    2014-02-01

    Graphic prints and manuscripts constitute main part of the cultural heritage objects created by the most of the known civilizations. Their presentation was always a problem due to their high sensitivity to light and changes of external conditions (temperature, humidity). Today it is possible to use an advanced digitalization techniques for documentation and visualization of mentioned objects. In the situation when presentation of the original heritage object is impossible, there is a need to develop a method allowing documentation and then presentation to the audience of all the aesthetical features of the object. During the course of the project scans of several pages of one of the most valuable books in collection of Museum of Warsaw Archdiocese were performed. The book known as "Great Dürer Trilogy" consists of three series of woodcuts by the Albrecht Dürer. The measurement system used consists of a custom designed, structured light-based, high-resolution measurement head with automated digitization system mounted on the industrial robot. This device was custom built to meet conservators' requirements, especially the lack of ultraviolet or infrared radiation emission in the direction of measured object. Documentation of one page from the book requires about 380 directional measurements which constitute about 3 billion sample points. The distance between the points in the cloud is 20 μm. Provided that the measurement with MSD (measurement sampling density) of 2500 points makes it possible to show to the publicity the spatial structure of this graphics print. An important aspect is the complexity of the software environment created for data processing, in which massive data sets can be automatically processed and visualized. Very important advantage of the software which is using directly clouds of points is the possibility to manipulate freely virtual light source.

  9. 3D µCT and SEM Analysis of Resolidified Tips of Cored Wires Used in Twin-Wire Arc Spraying

    NASA Astrophysics Data System (ADS)

    Nellesen, J.; Abdulgader, M.; Tillmann, W.; Beckmann, F.

    2015-01-01

    In twin-wire arc spraying (TWAS), the in-flight particles are atomized from a melting bath which generates an inhomogeneous spraying plume. This inhomogeneity is due to the fact that these particles are generated by the impingement of fast continuous flowing air upon the melting tips of electrically conductive wires. This work aims to contribute to the understanding of the initiation of such particles in the TWAS process. For this purpose, cored wires filled with W-rich particles were sprayed. After interrupting the TWAS process, the tips of these cored wires were imaged by 3D µCT and scanning electron microscopy in order to analyze how the filling powder interacts with the melted part of the sheath. The analysis of the 3D tomograms shows that the resolidified melting bath of the cored wires is interspersed with both spherical and irregular-shaped W-rich particles. This irregular shape suggests a partial melting of the W-rich particles.

  10. Terrestrial and Aerial Laser Scanning Data Integration Using Wavelet Analysis for the Purpose of 3D Building Modeling

    PubMed Central

    Kedzierski, Michal; Fryskowska, Anna

    2014-01-01

    Visualization techniques have been greatly developed in the past few years. Three-dimensional models based on satellite and aerial imagery are now being enhanced by models generated using Aerial Laser Scanning (ALS) data. The most modern of such scanning systems have the ability to acquire over 50 points per square meter and to register a multiple echo, which allows the reconstruction of the terrain together with the terrain cover. However, ALS data accuracy is less than 10 cm and the data is often incomplete: there is no information about ground level (in most scanning systems), and often around the facade or structures which have been covered by other structures. However, Terrestrial Laser Scanning (TLS) not only acquires higher accuracy data (1–5 cm) but is also capable of registering those elements which are incomplete or not visible using ALS methods (facades, complicated structures, interiors, etc.). Therefore, to generate a complete 3D model of a building in high Level of Details, integration of TLS and ALS data is necessary. This paper presents the wavelet-based method of processing and integrating data from ALS and TLS. Methods of choosing tie points to combine point clouds in different datum will be analyzed. PMID:25004157

  11. Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer

    NASA Astrophysics Data System (ADS)

    Kolappan Geetha, Ganesh; Roy Mahapatra, D.; Srinivasan, Gopalakrishnan

    2012-04-01

    Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

  12. Classification of pulmonary emphysema from chest CT scans using integral geometry descriptors

    NASA Astrophysics Data System (ADS)

    van Rikxoort, E. M.; Goldin, J. G.; Galperin-Aizenberg, M.; Brown, M. S.

    2011-03-01

    To gain insight into the underlying pathways of emphysema and monitor the effect of treatment, methods to quantify and phenotype the different types of emphysema from chest CT scans are of crucial importance. Current standard measures rely on density thresholds for individual voxels, which is influenced by inspiration level and does not take into account the spatial relationship between voxels. Measures based on texture analysis do take the interrelation between voxels into account and therefore might be useful for distinguishing different types of emphysema. In this study, we propose to use Minkowski functionals combined with rotation invariant Gaussian features to distinguish between healthy and emphysematous tissue and classify three different types of emphysema. Minkowski functionals characterize binary images in terms of geometry and topology. In 3D, four Minkowski functionals are defined. By varying the threshold and size of neighborhood around a voxel, a set of Minkowski functionals can be defined for each voxel. Ten chest CT scans with 1810 annotated regions were used to train the method. A set of 108 features was calculated for each training sample from which 10 features were selected to be most informative. A linear discriminant classifier was trained to classify each voxel in the lungs into a subtype of emphysema or normal lung. The method was applied to an independent test set of 30 chest CT scans with varying amounts and types of emphysema with 4347 annotated regions of interest. The method is shown to perform well, with an overall accuracy of 95%.

  13. Automated torso organ segmentation from 3D CT images using structured perceptron and dual decomposition

    NASA Astrophysics Data System (ADS)

    Nimura, Yukitaka; Hayashi, Yuichiro; Kitasaka, Takayuki; Mori, Kensaku

    2015-03-01

    This paper presents a method for torso organ segmentation from abdominal CT images using structured perceptron and dual decomposition. A lot of methods have been proposed to enable automated extraction of organ regions from volumetric medical images. However, it is necessary to adjust empirical parameters of them to obtain precise organ regions. This paper proposes an organ segmentation method using structured output learning. Our method utilizes a graphical model and binary features which represent the relationship between voxel intensities and organ labels. Also we optimize the weights of the graphical model by structured perceptron and estimate the best organ label for a given image by dynamic programming and dual decomposition. The experimental result revealed that the proposed method can extract organ regions automatically using structured output learning. The error of organ label estimation was 4.4%. The DICE coefficients of left lung, right lung, heart, liver, spleen, pancreas, left kidney, right kidney, and gallbladder were 0.91, 0.95, 0.77, 0.81, 0.74, 0.08, 0.83, 0.84, and 0.03, respectively.

  14. Characterization of image quality for 3D scatter-corrected breast CT images

    NASA Astrophysics Data System (ADS)

    Pachon, Jan H.; Shah, Jainil; Tornai, Martin P.

    2011-03-01

    The goal of this study was to characterize the image quality of our dedicated, quasi-monochromatic spectrum, cone beam breast imaging system under scatter corrected and non-scatter corrected conditions for a variety of breast compositions. CT projections were acquired of a breast phantom containing two concentric sets of acrylic spheres that varied in size (1-8mm) based on their polar position. The breast phantom was filled with 3 different concentrations of methanol and water, simulating a range of breast densities (0.79-1.0g/cc); acrylic yarn was sometimes included to simulate connective tissue of a breast. For each phantom condition, 2D scatter was measured for all projection angles. Scatter-corrected and uncorrected projections were then reconstructed with an iterative ordered subsets convex algorithm. Reconstructed image quality was characterized using SNR and contrast analysis, and followed by a human observer detection task for the spheres in the different concentric rings. Results show that scatter correction effectively reduces the cupping artifact and improves image contrast and SNR. Results from the observer study indicate that there was no statistical difference in the number or sizes of lesions observed in the scatter versus non-scatter corrected images for all densities. Nonetheless, applying scatter correction for differing breast conditions improves overall image quality.

  15. Anatomy of hepatic arteriolo-portal venular shunts evaluated by 3D micro-CT imaging

    PubMed Central

    Kline, Timothy L; Knudsen, Bruce E; Anderson, Jill L; Vercnocke, Andrew J; Jorgensen, Steven M; Ritman, Erik L

    2014-01-01

    The liver differs from other organs in that two vascular systems deliver its blood – the hepatic artery and the portal vein. However, how the two systems interact is not fully understood. We therefore studied the microvascular geometry of rat liver hepatic artery and portal vein injected with the contrast polymer Microfil®. Intact isolated rat livers were imaged by micro-CT and anatomic evidence for hepatic arteriolo-portal venular shunts occurring between hepatic artery and portal vein branches was found. Simulations were performed to rule out the possibility of the observed shunts being artifacts resulting from image blurring. In addition, in the case of specimens where only the portal vein was injected, only the portal vein was opacified, whereas in hepatic artery injections, both the hepatic artery and portal vein were opacified. We conclude that mixing of the hepatic artery and portal vein blood can occur proximal to the sinusoidal level, and that the hepatic arteriolo-portal venular shunts may function as a one-way valve-like mechanism, allowing flow only from the hepatic artery to the portal vein (and not the other way around). PMID:24684343

  16. Initial experience with optical-CT scanning of RadBall Dosimeters.

    PubMed

    Oldham, M; Clift, C; Thomas, A; Farfan, E; Foley, T; Jannik, T; Adamovics, J; Holmes, C; Stanley, S

    2010-12-01

    The RadBall dosimeter is a novel device for providing 3-D information on the magnitude and distribution of contaminant sources of unknown radiation in a given hot cell, glovebox, or contaminated room. The device is presently under evaluation by the National Nuclear Lab (NNL, UK) and the Savannah River National Laboratory (SRNL, US), for application as a diagnostic device for such unknown contaminants in the nuclear industry. A critical component of the technique is imaging the dose distribution recorded in the RadBall using optical-CT scanning. Here we present our initial investigations using the Duke Mid-sized Optical-CT Scanner (DMOS) to image dose distributions deposited in RadBalls exposed to a variety of radiation treatments. PMID:21218190

  17. Initial experience with optical-CT scanning of RadBall Dosimeters

    PubMed Central

    Oldham, M; Clift, C; Thomas, A; Farfan, E; Foley, T; Jannik, T; Adamovics, J; Holmes, C; Stanley, S

    2010-01-01

    The RadBall dosimeter is a novel device for providing 3-D information on the magnitude and distribution of contaminant sources of unknown radiation in a given hot cell, glovebox, or contaminated room. The device is presently under evaluation by the National Nuclear Lab (NNL, UK) and the Savannah River National Laboratory (SRNL, US), for application as a diagnostic device for such unknown contaminants in the nuclear industry. A critical component of the technique is imaging the dose distribution recorded in the RadBall using optical-CT scanning. Here we present our initial investigations using the Duke Mid-sized Optical-CT Scanner (DMOS) to image dose distributions deposited in RadBalls exposed to a variety of radiation treatments. PMID:21218190

  18. Initial experience with optical-CT scanning of RadBall Dosimeters

    NASA Astrophysics Data System (ADS)

    Oldham, M.; Clift, C.; Thomas, A.; Farfan, E.; Foley, T.; Jannik, T.; Adamovics J.; Holmes, C.; Stanley, S.

    2010-11-01

    The RadBall dosimeter is a novel device for providing 3-D information on the magnitude and distribution of contaminant sources of unknown radiation in a given hot cell, glovebox, or contaminated room. The device is presently under evaluation by the National Nuclear Lab (NNL, UK) and the Savannah River National Laboratory (SRNL, US), for application as a diagnostic device for such unknown contaminants in the nuclear industry. A critical component of the technique is imaging the dose distribution recorded in the RadBall using optical-CT scanning. Here we present our initial investigations using the Duke Mid-sized Optical-CT Scanner (DMOS) to image dose distributions deposited in RadBalls exposed to a variety of radiation treatments.

  19. A robust and efficient approach to detect 3D rectal tubes from CT colonography

    SciTech Connect

    Yang Xiaoyun; Slabaugh, Greg

    2011-11-15

    Purpose: The rectal tube (RT) is a common source of false positives (FPs) in computer-aided detection (CAD) systems for CT colonography. A robust and efficient detection of RT can improve CAD performance by eliminating such ''obvious'' FPs and increase radiologists' confidence in CAD. Methods: In this paper, we present a novel and robust bottom-up approach to detect the RT. Probabilistic models, trained using kernel density estimation on simple low-level features, are employed to rank and select the most likely RT tube candidate on each axial slice. Then, a shape model, robustly estimated using random sample consensus (RANSAC), infers the global RT path from the selected local detections. Subimages around the RT path are projected into a subspace formed from training subimages of the RT. A quadratic discriminant analysis (QDA) provides a classification of a subimage as RT or non-RT based on the projection. Finally, a bottom-top clustering method is proposed to merge the classification predictions together to locate the tip position of the RT. Results: Our method is validated using a diverse database, including data from five hospitals. On a testing data with 21 patients (42 volumes), 99.5% of annotated RT paths have been successfully detected. Evaluated with CAD, 98.4% of FPs caused by the RT have been detected and removed without any loss of sensitivity. Conclusions: The proposed method demonstrates a high detection rate of the RT path, and when tested in a CAD system, reduces FPs caused by the RT without the loss of sensitivity.

  20. Object-constrained meshless deformable algorithm for high speed 3D nonrigid registration between CT and CBCT

    SciTech Connect

    Chen Ting; Kim, Sung; Goyal, Sharad; Jabbour, Salma; Zhou Jinghao; Rajagopal, Gunaretnum; Haffty, Bruce; Yue Ning

    2010-01-15

    Purpose: High-speed nonrigid registration between the planning CT and the treatment CBCT data is critical for real time image guided radiotherapy (IGRT) to improve the dose distribution and to reduce the toxicity to adjacent organs. The authors propose a new fully automatic 3D registration framework that integrates object-based global and seed constraints with the grayscale-based ''demons'' algorithm. Methods: Clinical objects were segmented on the planning CT images and were utilized as meshless deformable models during the nonrigid registration process. The meshless models reinforced a global constraint in addition to the grayscale difference between CT and CBCT in order to maintain the shape and the volume of geometrically complex 3D objects during the registration. To expedite the registration process, the framework was stratified into hierarchies, and the authors used a frequency domain formulation to diffuse the displacement between the reference and the target in each hierarchy. Also during the registration of pelvis images, they replaced the air region inside the rectum with estimated pixel values from the surrounding rectal wall and introduced an additional seed constraint to robustly track and match the seeds implanted into the prostate. The proposed registration framework and algorithm were evaluated on 15 real prostate cancer patients. For each patient, prostate gland, seminal vesicle, bladder, and rectum were first segmented by a radiation oncologist on planning CT images for radiotherapy planning purpose. The same radiation oncologist also manually delineated the tumor volumes and critical anatomical structures in the corresponding CBCT images acquired at treatment. These delineated structures on the CBCT were only used as the ground truth for the quantitative validation, while structures on the planning CT were used both as the input to the registration method and the ground truth in validation. By registering the planning CT to the CBCT, a

  1. Pregnant female anthropometry from ct scans for finite element model development.

    PubMed

    Loftis, Kathryn; Halsey, Michael; Anthony, Evelyn; Duma, Stefan M; Stitzel, Joel

    2008-01-01

    In this study, anthropometry data is collected from a CT scan of a pregnant abdomen at 32 weeks gestation. Over 1500 fetal losses occur each year in the United States due to motor vehicles crashes. Pregnant occupants involved in motor vehicle crashes are at risk for pregnancy-specific injuries. Masks of the fetus, uterus, placenta, and each of the abdominal organs are created by segmentation of the CT slices and three-dimensional volume renderings are formed. The volume and Hounsfield unit ranges for the masks of each abdominal organ are calculated. The total volume of the uterus in the 3rd trimester is measured as 3378 cm3. By measuring the length of bones on the fetal skeleton from CT slices and the 3D rendering, the gestational age of the fetus is estimated to be 32 weeks by comparison with literature values. Measurements of each of the abdominal organs are also obtained from the 3D rendering to create a blueprint of the pregnant anatomy. The masks developed and the anthropometric measurements taken will be used to develop a more accurate FE model of the pregnant female for use in the research and development in academia, industry, and government. PMID:19141941

  2. On the feasibility of polyurethane based 3D dosimeters with optical CT for dosimetric verification of low energy photon brachytherapy seeds

    PubMed Central

    Adamson, Justus; Yang, Yun; Juang, Titania; Chisholm, Kelsey; Rankine, Leith; Adamovics, John; Yin, Fang Fang; Oldham, Mark

    2014-01-01

    Purpose: To investigate the feasibility of and challenges yet to be addressed to measure dose from low energy (effective energy <50 keV) brachytherapy sources (Pd-103, Cs-131, and I-125) using polyurethane based 3D dosimeters with optical CT. Methods: The authors' evaluation used the following sources: models 200 (Pd-103), CS-1 Rev2 (Cs-131), and 6711 (I-125). The authors used the Monte Carlo radiation transport code MCNP5, simulations with the ScanSim optical tomography simulation software, and experimental measurements with PRESAGE® dosimeters/optical CT to investigate the following: (1) the water equivalency of conventional (density = 1.065 g/cm3) and deformable (density = 1.02 g/cm3) formulations of polyurethane dosimeters, (2) the scatter conditions necessary to achieve accurate dosimetry for low energy photon seeds, (3) the change in photon energy spectrum within the dosimeter as a function of distance from the source in order to determine potential energy sensitivity effects, (4) the optimal delivered dose to balance optical transmission (per projection) with signal to noise ratio in the reconstructed dose distribution, and (5) the magnitude and characteristics of artifacts due to the presence of a channel in the dosimeter. Monte Carlo simulations were performed using both conventional and deformable dosimeter formulations. For verification, 2.8 Gy at 1 cm was delivered in 92 h using an I-125 source to a PRESAGE® dosimeter with conventional formulation and a central channel with 0.0425 cm radius for source placement. The dose distribution was reconstructed with 0.02 and 0.04 cm3 voxel size using the Duke midsized optical CT scanner (DMOS). Results: While the conventional formulation overattenuates dose from all three sources compared to water, the current deformable formulation has nearly water equivalent attenuation properties for Cs-131 and I-125, while underattenuating for Pd-103. The energy spectrum of each source is relatively stable within the first

  3. On the feasibility of polyurethane based 3D dosimeters with optical CT for dosimetric verification of low energy photon brachytherapy seeds

    SciTech Connect

    Adamson, Justus Yang, Yun; Juang, Titania; Chisholm, Kelsey; Rankine, Leith; Yin, Fang Fang; Oldham, Mark; Adamovics, John

    2014-07-15

    Purpose: To investigate the feasibility of and challenges yet to be addressed to measure dose from low energy (effective energy <50 keV) brachytherapy sources (Pd-103, Cs-131, and I-125) using polyurethane based 3D dosimeters with optical CT. Methods: The authors' evaluation used the following sources: models 200 (Pd-103), CS-1 Rev2 (Cs-131), and 6711 (I-125). The authors used the Monte Carlo radiation transport code MCNP5, simulations with the ScanSim optical tomography simulation software, and experimental measurements with PRESAGE{sup ®} dosimeters/optical CT to investigate the following: (1) the water equivalency of conventional (density = 1.065 g/cm{sup 3}) and deformable (density = 1.02 g/cm{sup 3}) formulations of polyurethane dosimeters, (2) the scatter conditions necessary to achieve accurate dosimetry for low energy photon seeds, (3) the change in photon energy spectrum within the dosimeter as a function of distance from the source in order to determine potential energy sensitivity effects, (4) the optimal delivered dose to balance optical transmission (per projection) with signal to noise ratio in the reconstructed dose distribution, and (5) the magnitude and characteristics of artifacts due to the presence of a channel in the dosimeter. Monte Carlo simulations were performed using both conventional and deformable dosimeter formulations. For verification, 2.8 Gy at 1 cm was delivered in 92 h using an I-125 source to a PRESAGE{sup ®} dosimeter with conventional formulation and a central channel with 0.0425 cm radius for source placement. The dose distribution was reconstructed with 0.02 and 0.04 cm{sup 3} voxel size using the Duke midsized optical CT scanner (DMOS). Results: While the conventional formulation overattenuates dose from all three sources compared to water, the current deformable formulation has nearly water equivalent attenuation properties for Cs-131 and I-125, while underattenuating for Pd-103. The energy spectrum of each source is

  4. Semi-automatic classification of textures in thoracic CT scans

    NASA Astrophysics Data System (ADS)

    Kockelkorn, Thessa T. J. P.; de Jong, Pim A.; Schaefer-Prokop, Cornelia M.; Wittenberg, Rianne; Tiehuis, Audrey M.; Gietema, Hester A.; Grutters, Jan C.; Viergever, Max A.; van Ginneken, Bram

    2016-08-01

    The textural patterns in the lung parenchyma, as visible on computed tomography (CT) scans, are essential to make a correct diagnosis in interstitial lung disease. We developed one automatic and two interactive protocols for classification of normal and seven types of abnormal lung textures. Lungs were segmented and subdivided into volumes of interest (VOIs) with homogeneous texture using a clustering approach. In the automatic protocol, VOIs were classified automatically by an extra-trees classifier that was trained using annotations of VOIs from other CT scans. In the interactive protocols, an observer iteratively trained an extra-trees classifier to distinguish the different textures, by correcting mistakes the classifier makes in a slice-by-slice manner. The difference between the two interactive methods was whether or not training data from previously annotated scans was used in classification of the first slice. The protocols were compared in terms of the percentages of VOIs that observers needed to relabel. Validation experiments were carried out using software that simulated observer behavior. In the automatic classification protocol, observers needed to relabel on average 58% of the VOIs. During interactive annotation without the use of previous training data, the average percentage of relabeled VOIs decreased from 64% for the first slice to 13% for the second half of the scan. Overall, 21% of the VOIs were relabeled. When previous training data was available, the average overall percentage of VOIs requiring relabeling was 20%, decreasing from 56% in the first slice to 13% in the second half of the scan.

  5. The Monte Carlo SRNA-VOX code for 3D proton dose distribution in voxelized geometry using CT data

    NASA Astrophysics Data System (ADS)

    Ilic, Radovan D.; Spasic-Jokic, Vesna; Belicev, Petar; Dragovic, Milos

    2005-03-01

    This paper describes the application of the SRNA Monte Carlo package for proton transport simulations in complex geometry and different material compositions. The SRNA package was developed for 3D dose distribution calculation in proton therapy and dosimetry and it was based on the theory of multiple scattering. The decay of proton induced compound nuclei was simulated by the Russian MSDM model and our own using ICRU 63 data. The developed package consists of two codes: the SRNA-2KG, which simulates proton transport in combinatorial geometry and the SRNA-VOX, which uses the voxelized geometry using the CT data and conversion of the Hounsfield's data to tissue elemental composition. Transition probabilities for both codes are prepared by the SRNADAT code. The simulation of the proton beam characterization by multi-layer Faraday cup, spatial distribution of positron emitters obtained by the SRNA-2KG code and intercomparison of computational codes in radiation dosimetry, indicate immediate application of the Monte Carlo techniques in clinical practice. In this paper, we briefly present the physical model implemented in the SRNA package, the ISTAR proton dose planning software, as well as the results of the numerical experiments with proton beams to obtain 3D dose distribution in the eye and breast tumour.

  6. The Monte Carlo SRNA-VOX code for 3D proton dose distribution in voxelized geometry using CT data.

    PubMed

    Ilić, Radovan D; Spasić-Jokić, Vesna; Belicev, Petar; Dragović, Milos

    2005-03-01

    This paper describes the application of the SRNA Monte Carlo package for proton transport simulations in complex geometry and different material compositions. The SRNA package was developed for 3D dose distribution calculation in proton therapy and dosimetry and it was based on the theory of multiple scattering. The decay of proton induced compound nuclei was simulated by the Russian MSDM model and our own using ICRU 63 data. The developed package consists of two codes: the SRNA-2KG, which simulates proton transport in combinatorial geometry and the SRNA-VOX, which uses the voxelized geometry using the CT data and conversion of the Hounsfield's data to tissue elemental composition. Transition probabilities for both codes are prepared by the SRNADAT code. The simulation of the proton beam characterization by multi-layer Faraday cup, spatial distribution of positron emitters obtained by the SRNA-2KG code and intercomparison of computational codes in radiation dosimetry, indicate immediate application of the Monte Carlo techniques in clinical practice. In this paper, we briefly present the physical model implemented in the SRNA package, the ISTAR proton dose planning software, as well as the results of the numerical experiments with proton beams to obtain 3D dose distribution in the eye and breast tumour. PMID:15798273

  7. Bone canalicular network segmentation in 3D nano-CT images through geodesic voting and image tessellation

    NASA Astrophysics Data System (ADS)

    Zuluaga, Maria A.; Orkisz, Maciej; Dong, Pei; Pacureanu, Alexandra; Gouttenoire, Pierre-Jean; Peyrin, Françoise

    2014-05-01

    Recent studies emphasized the role of the bone lacuno-canalicular network (LCN) in the understanding of bone diseases such as osteoporosis. However, suitable methods to investigate this structure are lacking. The aim of this paper is to introduce a methodology to segment the LCN from three-dimensional (3D) synchrotron radiation nano-CT images. Segmentation of such structures is challenging due to several factors such as limited contrast and signal-to-noise ratio, partial volume effects and huge number of data that needs to be processed, which restrains user interaction. We use an approach based on minimum-cost paths and geodesic voting, for which we propose a fully automatic initialization scheme based on a tessellation of the image domain. The centroids of pre-segmented lacunæ are used as Voronoi-tessellation seeds and as start-points of a fast-marching front propagation, whereas the end-points are distributed in the vicinity of each Voronoi-region boundary. This initialization scheme was devised to cope with complex biological structures involving cells interconnected by multiple thread-like, branching processes, while the seminal geodesic-voting method only copes with tree-like structures. Our method has been assessed quantitatively on phantom data and qualitatively on real datasets, demonstrating its feasibility. To the best of our knowledge, presented 3D renderings of lacunæ interconnected by their canaliculi were achieved for the first time.

  8. Bone canalicular network segmentation in 3D nano-CT images through geodesic voting and image tessellation.

    PubMed

    Zuluaga, Maria A; Orkisz, Maciej; Dong, Pei; Pacureanu, Alexandra; Gouttenoire, Pierre-Jean; Peyrin, Françoise

    2014-05-01

    Recent studies emphasized the role of the bone lacuno-canalicular network (LCN) in the understanding of bone diseases such as osteoporosis. However, suitable methods to investigate this structure are lacking. The aim of this paper is to introduce a methodology to segment the LCN from three-dimensional (3D) synchrotron radiation nano-CT images. Segmentation of such structures is challenging due to several factors such as limited contrast and signal-to-noise ratio, partial volume effects and huge number of data that needs to be processed, which restrains user interaction. We use an approach based on minimum-cost paths and geodesic voting, for which we propose a fully automatic initialization scheme based on a tessellation of the image domain. The centroids of pre-segmented lacunæ are used as Voronoi-tessellation seeds and as start-points of a fast-marching front propagation, whereas the end-points are distributed in the vicinity of each Voronoi-region boundary. This initialization scheme was devised to cope with complex biological structures involving cells interconnected by multiple thread-like, branching processes, while the seminal geodesic-voting method only copes with tree-like structures. Our method has been assessed quantitatively on phantom data and qualitatively on real datasets, demonstrating its feasibility. To the best of our knowledge, presented 3D renderings of lacunæ interconnected by their canaliculi were achieved for the first time. PMID:24710691

  9. SU-E-T-294: Simulations to Investigate the Feasibility of ‘dry’ Optical-CT Imaging for 3D Dosimetry

    SciTech Connect

    Chisholm, K; Rankine, L; Oldham, M

    2014-06-01

    Purpose: To perform simulations investigating the feasibility of “dry” optical-CT, and determine optimal design and scanning parameters for a novel dry tank telecentric optical-CT 3D dosimetry system. Such a system would have important advantages in terms of practical convenience and reduced cost. Methods: A Matlab based ray-tracing simulation platform, ScanSim, was used to model a telecentric system with a polyurethane dry tank, cylindrical dosimeter, and surrounding fluid. This program's capabilities were expanded for the geometry and physics of dry scanning. To categorize the effects of refractive index (RI) mismatches, simulations were run for several dosimeter (RI = 1.5−1.48) and fluid (RI = 1.55−1.33) combinations. Additional simulations examined the effect of increasing gap size (1–5mm) between the dosimeter and tank wall, and of changing the telecentric lens tolerance (0.5°−5°). The evaluation metric is the usable radius; the distance from the dosimeter center where the measured and true doses differ by less than 2%. Results: As the tank/dosimeter RI mismatch increases from 0–0.02, the usable radius decreases from 97.6% to 50.2%. The fluid RI for matching is lower than either the tank or dosimeter RI. Changing gap sizes has drastic effects on the usable radius, requiring more closely matched fluid at large gap sizes. Increasing the telecentric tolerance through a range from 0.5°–5.0° improved the usable radius for every combination of media. Conclusion: Dry optical-CT with telecentric lenses is feasible when the dosimeter and tank RIs are closely matched (<0.01 difference), or when data in the periphery is not required. The ScanSim tool proved very useful in situations when the tank and dosimeter have slight differences in RI by enabling estimation of the optimal choice of RI of the small amount of fluid still required. Some spoiling of the telecentric beam and increasing the tolerance helps recover the usable radius.

  10. Integrated 3D view of postmating responses by the Drosophila melanogaster female reproductive tract, obtained by micro-computed tomography scanning.

    PubMed

    Mattei, Alexandra L; Riccio, Mark L; Avila, Frank W; Wolfner, Mariana F

    2015-07-01

    Physiological changes in females during and after mating are triggered by seminal fluid components in conjunction with female-derived molecules. In insects, these changes include increased egg production, storage of sperm, and changes in muscle contraction within the reproductive tract (RT). Such postmating changes have been studied in dissected RT tissues, but understanding their coordination in vivo requires a holistic view of the tissues and their interrelationships. Here, we used high-resolution, multiscale micro-computed tomography (CT) scans to visualize and measure postmating changes in situ in the Drosophila female RT before, during, and after mating. These studies reveal previously unidentified dynamic changes in the conformation of the female RT that occur after mating. Our results also reveal how the reproductive organs temporally shift in concert within the confines of the abdomen. For example, we observed chiral loops in the uterus and in the upper common oviduct that relax and constrict throughout sperm storage and egg movement. We found that specific seminal fluid proteins or female secretions mediate some of the postmating changes in morphology. The morphological movements, in turn, can cause further changes due to the connections among organs. In addition, we observed apparent copulatory damage to the female intima, suggesting a mechanism for entry of seminal proteins, or other exogenous components, into the female's circulatory system. The 3D reconstructions provided by high-resolution micro-CT scans reveal how male and female molecules and anatomy interface to carry out and coordinate mating-dependent changes in the female's reproductive physiology. PMID:26041806

  11. Integrated 3D view of postmating responses by the Drosophila melanogaster female reproductive tract, obtained by micro-computed tomography scanning

    PubMed Central

    Mattei, Alexandra L.; Riccio, Mark L.; Avila, Frank W.; Wolfner, Mariana F.

    2015-01-01

    Physiological changes in females during and after mating are triggered by seminal fluid components in conjunction with female-derived molecules. In insects, these changes include increased egg production, storage of sperm, and changes in muscle contraction within the reproductive tract (RT). Such postmating changes have been studied in dissected RT tissues, but understanding their coordination in vivo requires a holistic view of the tissues and their interrelationships. Here, we used high-resolution, multiscale micro-computed tomography (CT) scans to visualize and measure postmating changes in situ in the Drosophila female RT before, during, and after mating. These studies reveal previously unidentified dynamic changes in the conformation of the female RT that occur after mating. Our results also reveal how the reproductive organs temporally shift in concert within the confines of the abdomen. For example, we observed chiral loops in the uterus and in the upper common oviduct that relax and constrict throughout sperm storage and egg movement. We found that specific seminal fluid proteins or female secretions mediate some of the postmating changes in morphology. The morphological movements, in turn, can cause further changes due to the connections among organs. In addition, we observed apparent copulatory damage to the female intima, suggesting a mechanism for entry of seminal proteins, or other exogenous components, into the female’s circulatory system. The 3D reconstructions provided by high-resolution micro-CT scans reveal how male and female molecules and anatomy interface to carry out and coordinate mating-dependent changes in the female’s reproductive physiology. PMID:26041806

  12. SU-C-BRB-06: Utilizing 3D Scanner and Printer for Dummy Eye-Shield: Artifact-Free CT Images of Tungsten Eye-Shield for Accurate Dose Calculation

    SciTech Connect

    Park, J; Lee, J; Kim, H; Kim, I; Ye, S

    2015-06-15

    Purpose: To evaluate the effect of a tungsten eye-shield on the dose distribution of a patient. Methods: A 3D scanner was used to extract the dimension and shape of a tungsten eye-shield in the STL format. Scanned data was transferred into a 3D printer. A dummy eye shield was then produced using bio-resin (3D systems, VisiJet M3 Proplast). For a patient with mucinous carcinoma, the planning CT was obtained with the dummy eye-shield placed on the patient’s right eye. Field shaping of 6 MeV was performed using a patient-specific cerrobend block on the 15 x 15 cm{sup 2} applicator. The gantry angle was 330° to cover the planning target volume near by the lens. EGS4/BEAMnrc was commissioned from our measurement data from a Varian 21EX. For the CT-based dose calculation using EGS4/DOSXYZnrc, the CT images were converted to a phantom file through the ctcreate program. The phantom file had the same resolution as the planning CT images. By assigning the CT numbers of the dummy eye-shield region to 17000, the real dose distributions below the tungsten eye-shield were calculated in EGS4/DOSXYZnrc. In the TPS, the CT number of the dummy eye-shield region was assigned to the maximum allowable CT number (3000). Results: As compared to the maximum dose, the MC dose on the right lens or below the eye shield area was less than 2%, while the corresponding RTP calculated dose was an unrealistic value of approximately 50%. Conclusion: Utilizing a 3D scanner and a 3D printer, a dummy eye-shield for electron treatment can be easily produced. The artifact-free CT images were successfully incorporated into the CT-bas