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Jason Geng - One of the best experts on this subject based on the ideXlab platform.
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Review of 3-D Endoscopic Surface Imaging Techniques
IEEE Sensors Journal, 2014Co-Authors: Jason GengAbstract:This paper provides an overview of state-of-the-art 3-D endoscopic Imaging technologies. Physical objects in the world are 3-D, yet traditional endoscopes can only acquire 2-D images that lack depth information. This fundamental restriction greatly limits our ability to perceive and understand the complexity of real world objects. Lack of 3-D information also hinders our ability to quantitatively measure 3-D objects. In both medical Imaging and industrial inspection applications, 3-D Surface Imaging capability would add one more dimension, literally and figuratively, to the existing Imaging technologies. Over the past decades, tremendous new technologies and methods emerged in the 3-D Surface Imaging field. In this paper, we first provide a classification of these technologies. We then describe each category in detail, with representative designs and examples. This overview would be useful to researchers in the field since it provides a snapshot of the current state-of-the-art, from which subsequent research in meaningful directions is encouraged. This overview also contributes to the efficiency of research by preventing unnecessary duplication of already performed research.
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Performance assessment of 3D Surface Imaging technique for medical Imaging applications
Emerging Digital Micromirror Device Based Systems and Applications V, 2013Co-Authors: Jason GengAbstract:Recent development in optical 3D Surface Imaging technologies provide better ways to digitalize the 3D Surface and its motion in real-time. The non-invasive 3D Surface Imaging approach has great potential for many medical Imaging applications, such as motion monitoring of radiotherapy, pre/post evaluation of plastic surgery and dermatology, to name a few. Various commercial 3D Surface Imaging systems have appeared on the market with different dimension, speed and accuracy. For clinical applications, the accuracy, reproducibility and robustness across the widely heterogeneous skin color, tone, texture, shape properties, and ambient lighting is very crucial. Till now, a systematic approach for evaluating the performance of different 3D Surface Imaging systems still yet exist. In this paper, we present a systematic performance assessment approach to 3D Surface Imaging system assessment for medical applications. We use this assessment approach to exam a new real-time Surface Imaging system we developed, dubbed "Neo3D Camera" , for image-guided radiotherapy (IGRT). The assessments include accuracy, field of view, coverage, repeatability, speed and sensitivity to environment, texture and color.
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Structured-light 3D Surface Imaging: a tutorial
Advances in Optics and Photonics, 2011Co-Authors: Jason GengAbstract:We provide a review of recent advances in 3D Surface Imaging technologies. We focus particularly on noncontact 3D Surface measurement techniques based on structured illumination. The high-speed and high-resolution pattern projection capability offered by the digital light projection technology, together with the recent advances in Imaging sensor technologies, may enable new generation systems for 3D Surface measurement applications that will provide much better functionality and performance than existing ones in terms of speed, accuracy, resolution, modularization, and ease of use. Performance indexes of 3D Imaging system are discussed, and various 3D Surface Imaging schemes are categorized, illustrated, and compared. Calibration techniques are also discussed, since they play critical roles in achieving the required precision. Numerous applications of 3D Surface Imaging technologies are discussed with several examples.
Todd Pawlicki - One of the best experts on this subject based on the ideXlab platform.
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The Role of Optical Surface Imaging Systems in Radiation Therapy.
Seminars in radiation oncology, 2018Co-Authors: Jeremy D.p. Hoisak, Todd PawlickiAbstract:Optical Surface Imaging is a nonradiographic, noninvasive technology for continuous localization of patients during radiation therapy. Surface-guided radiation therapy (SGRT) has been applied to many treatment sites including breast, intracranial, head and neck, and extremities. SGRT enables a reduction of initial setup variability, provides verification of immobilization continuously during treatment including at noncoplanar linac gantry angles, and provides dynamic Surface information for use in gated and breath-hold treatment techniques, all of which can permit reductions in the margins required to account for target localization uncertainty. Ancillary benefits from Surface Imaging include the ability to use immobilization techniques that confer greater comfort to patients, a reduction in Imaging dose through reduced radiographic localization requirements, and improvements to the speed, efficiency, and safety of clinical workflows. This review will describe the objectives of SGRT, review the commercially available Surface Imaging systems, and provide an overview of SGRT applications by treatment site. Limitations and future applications of surfacing Imaging systems are also discussed.
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SU‐E‐T‐570: Setup and Monitoring in SRS Treatments with Surface Imaging
Medical Physics, 2011Co-Authors: Laura Cervino, Steve B Jiang, N. Detorie, Matthew Taylor, Joshua D. Lawson, T Harry, Kevin T. Murphy, Arno J. Mundt, Todd PawlickiAbstract:Purpose: To evaluate the initial clinical experience with a frameless and maskless technique for stereotactic radiosurgery using minimal patient immobilization and real-time patient motion monitoring during treatment. Methods: The study considered the first 23 patients treated with this technique. Head positioning was achieved with a patient-specific head mold made out of expandable foam that conforms to the patientˈs head. The face of the patient is left open for maximal comfort. Motion of a region of interest consisting of the forehead, nose, eyes, and temporal bones, is monitored during treatment using a video Surface Imaging system (VisionRT, Inc, UK). Initial setup of the patient was performed with the Surface Imaging system using the Surface of the patient obtained from the treatment planning CT scan and verified with cone-beam CT (CBCT). Shifts provided by the CBCT and the duration of all the steps in the treatment process were recorded. Patients were monitored during treatment with Surface Imaging, and a beam hold-off was initiated when the patientˈs motion exceeded a pre-specified tolerance. Results: The average total setup time was 26 minutes, while the portion corresponding to Surface Imaging was 14 minutes. The average treatment time including setup was 40 minutes. Eight (35%) patients needed repositioning during the treatment. The average shifts identified from CBCT after initial setup with Surface Imaging were 1.85 mm in the AP direction, and less than 1.0 mm in the lateral and SI directions. Conclusions: The frameless and maskless treatment using minimal immobilization and Surface Imaging has proven to be fast and accurate enough for routine clinical use. Patient compliance is important. Setup time was greatly reduced with a couch extension with tilt and spin correction capabilities. An additional degree of semi-rigid immobilization would be helpful for patients that fall asleep and involuntarily move during the procedure.
Karabi Ghose - One of the best experts on this subject based on the ideXlab platform.
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The Colour and Stereo Surface Imaging System (CaSSIS) for the ExoMars Trace Gas Orbiter
Space Science Reviews, 2017Co-Authors: Nicholas Thomas, R. Ziethe, M. Erismann, Giulia Bruno, Gabriele Cremonese, M Gerber, T. Gerber, Matthias Brandli, Giovanni Bruno, Lisa Gambicorti, Karabi GhoseAbstract:The Colour and Stereo Surface Imaging System (CaSSIS) is the main Imaging system onboard the European Space Agency’s ExoMars Trace Gas Orbiter (TGO) which was launched on 14 March 2016. CaSSIS is intended to acquire moderately high resolution (4.6 m/pixel) targeted images of Mars at a rate of 10–20 images per day from a roughly circular orbit 400 km above the Surface. Each image can be acquired in up to four colours and stereo capability is foreseen by the use of a novel rotation mechanism. A typical product from one image acquisition will be a 9.5km×∼45km$9.5~\mbox{km} \times {\sim}45~\mbox{km}$ swath in full colour and stereo in one over-flight of the target thereby reducing atmospheric influences inherent in stereo and colour products from previous high resolution imagers. This paper describes the instrument including several novel technical solutions required to achieve the scientific requirements.
George T Y Chen - One of the best experts on this subject based on the ideXlab platform.
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Comparison of target registration errors for multiple image-guided techniques in accelerated partial breast irradiation.
International journal of radiation oncology biology physics, 2008Co-Authors: David P. Gierga, Alphonse G. Taghian, Marco Riboldi, J Turcotte, Greg Sharp, Steve B Jiang, George T Y ChenAbstract:Purpose External beam accelerated partial breast irradiation requires accurate localization of the target volume for each treatment fraction. Using the concept of target registration error (TRE), the performance of several methods of target localization was compared. Methods and Materials Twelve patients who underwent external beam accelerated partial breast irradiation were included in this study. TRE was quantified for four methods of image guidance: standard laser-based setup, kilovoltage Imaging of the chest wall, kilovoltage Imaging of surgically implanted clips, and three-dimensional Surface Imaging of the breast. The use of a reference Surface created from a free-breathing computed tomography scan and a reference Surface directly captured with three-dimensional video Imaging were compared. The effects of respiratory motion were also considered, and gating was used for 8 of 12 patients. Results The median value of the TRE for the laser, chest wall, and clip alignment was 7.1 mm ( n = 94), 5.4 mm ( n = 81), and 2.4 mm ( n = 93), respectively. The median TRE for gated Surface Imaging based on the first fraction reference Surface was 3.2 mm ( n = 49), and the TRE for gated Surface Imaging using the computed tomography-based reference Surface was 4.9 mm ( n = 56). The TRE for nongated Surface Imaging using the first fraction reference Surface was 6.2 mm ( n = 25). Conclusions The TRE of Surface Imaging using a reference Surface directly captured with three-dimensional video and the TRE for clip-based setup were within 1 mm. Gated capture is important for Surface Imaging to reduce the effects of respiratory motion in accelerated partial breast irradiation.
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a phantom evaluation of a stereo vision Surface Imaging system for radiotherapy patient setup
Medical Physics, 2005Co-Authors: Christoph Bert, Katherine G Metheany, Karen P Doppke, George T Y ChenAbstract:External beam irradiation requires precise positioning of the target relative to the treatment planning coordinate system. A three-dimensional (3D) Surface Imaging system for patient positioning has recently been installed in one of our linear accelerator (linac) rooms. The device utilizes close-range photogrammetry to generate a 3D model of the patient's Surface. This geometric model can be made to look like a digital camera image if wrapped with a gray-level image (texture mapping) that shows Surface coloration. The system is calibrated to the linac coordinate system and has been designed as a patient setup device. To reproduce patient position in fractionated radiotherapy, the daily patient Surface model is registered to a previously recorded reference Surface. Using Surface registration, the system calculates the rigid-body transformation that minimizes the distance between the treatment and the reference Surface models in a region-of-interest (ROI). This transformation is expressed as a set of new couch coordinates at which the patient position best matches with the reference data. If respiratory motion is a concern, the Surface can be obtained with a gated acquisition at a specified phase of the respiratory cycle. To analyze the accuracy of the system, we performed several experiments with phantoms to assess stability,more » alignment accuracy, precision of the gating function, and Surface topology. The reproducibility of Surface measurements was tested for periods up to 57 h. Each recorded frame was registered to the reference Surface to calculate the required couch adjustment. The system stability over this time period was better than 0.5 mm. To measure the accuracy of the system to detect and quantify patient shift relative to a reference image, we compared the shift detected by the Surface Imaging system with known couch transitions in a phantom study. The maximum standard deviation was 0.75 mm for the three translational degrees of freedom, and less than 0.1 deg. for each rotation. Surface model precision was tested against computed tomography (CT)-derived Surface topology. The root-mean-square rms of the distance between the Surfaces was 0.65 mm, excluding regions where beam hardening caused artifacts in the CT data. Measurements were made to test the gated acquisition mode. The time-dependent amplitude was measured with the Surface Imaging system and an established respiratory gating system based on infrared (IR)-marker detection. The measured motion trajectories from both systems were compared to the known trajectory of the stage. The standard deviations of the amplitude differences to the motor trajectory were 0.04 and 0.15 mm for the IR-marker system and the 3D Surface Imaging system, respectively. A limitation of the Surface-Imaging device is the frame rate of 6.5 Hz, because rapid changes of the motion trajectory cannot be detected. In conclusion, the system is accurate and sufficiently stable to be used in the clinic. The errors computed when comparing the Surface model with CT geometry were submillimeter, and deviations in the alignment and gating-signal tests were of the same magnitude.« less
David P. Gierga - One of the best experts on this subject based on the ideXlab platform.
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Analysis of setup uncertainties for extremity sarcoma patients using Surface Imaging
Practical radiation oncology, 2013Co-Authors: David P. Gierga, J Turcotte, Long W. Tong, Yen-lin Chen, Thomas F. DelaneyAbstract:Abstract Purpose Proper positioning of patients with extremity sarcoma tumors can be challenging. A Surface Imaging technique was utilized to quantify the setup uncertainties for sarcoma patients and to assess whether Surface Imaging could improve the accuracy of patient positioning. Methods and materials Pretreatment and posttreatment 3-dimensional (3D) Surface images were obtained for 16 patients and 236 treatments. Offline Surface registration was performed to quantify interfraction and intrafraction setup errors, and the required planning target volume (PTV) margins were calculated. Setup differences were also assessed using root mean square (RMS) error analysis. Results For intrafraction variation, the mean 3D vector shift was 2.1 mm, and the systematic and random errors were 1.3 mm or less. When using a reference Surface from the first fraction, the mean interfraction setup variation (3D vector shift) was 7.6 mm. Systematic and random errors were 3-4 mm in each direction. When using a computed tomographic based reference Surface, the mean 3D vector shift was 9.5 mm. Systematic and random errors ranged from 3.1 to 7.9 mm. The required PTV margins were 1.0 cm, 1.2 cm, and 1.3 cm in the anterior–posterior, superior–inferior, and lateral directions, respectively. The mean (standard deviation) RMS errors for the uncorrected position were 4.7 mm (1.9 mm) and were reduced to 2.2 mm (0.8 mm) and 1.7 mm (0.8 mm), for 4 degree of freedom (DOF) and 6 DOF Surface alignment, respectively. Conclusions Intrafraction motion is small. Interfraction motion can exceed typical PTV margins and daily Imaging should be utilized to reduce setup variations. Surface Imaging may reduce setup errors and is a feasible technique for daily image guidance.
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a voluntary breath hold treatment technique for the left breast with unfavorable cardiac anatomy using Surface Imaging
International Journal of Radiation Oncology Biology Physics, 2012Co-Authors: David P. Gierga, J Turcotte, G Sharp, Daniel E Sedlacek, Christopher Cotter, Alphonse G. TaghianAbstract:Purpose Breath-hold (BH) treatments can be used to reduce cardiac dose for patients with left-sided breast cancer and unfavorable cardiac anatomy. A Surface Imaging technique was developed for accurate patient setup and reproducible real-time BH positioning. Methods and Materials Three-dimensional Surface images were obtained for 20 patients. Surface Imaging was used to correct the daily setup for each patient. Initial setup data were recorded for 443 fractions and were analyzed to assess random and systematic errors. Real time monitoring was used to verify Surface placement during BH. The radiation beam was not turned on if the BH position difference was greater than 5 mm. Real-time Surface data were analyzed for 2398 BHs and 363 treatment fractions. The mean and maximum differences were calculated. The percentage of BHs greater than tolerance was calculated. Results The mean shifts for initial patient setup were 2.0 mm, 1.2 mm, and 0.3 mm in the vertical, longitudinal, and lateral directions, respectively. The mean 3-dimensional vector shift was 7.8 mm. Random and systematic errors were less than 4 mm. Real-time Surface monitoring data indicated that 22% of the BHs were outside the 5-mm tolerance (range, 7%-41%), and there was a correlation with breast volume. The mean difference between the treated and reference BH positions was 2 mm in each direction. For out-of-tolerance BHs, the average difference in the BH position was 6.3 mm, and the average maximum difference was 8.8 mm. Conclusions Daily real-time Surface Imaging ensures accurate and reproducible positioning for BH treatment of left-sided breast cancer patients with unfavorable cardiac anatomy.
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Comparison of target registration errors for multiple image-guided techniques in accelerated partial breast irradiation.
International journal of radiation oncology biology physics, 2008Co-Authors: David P. Gierga, Alphonse G. Taghian, Marco Riboldi, J Turcotte, Greg Sharp, Steve B Jiang, George T Y ChenAbstract:Purpose External beam accelerated partial breast irradiation requires accurate localization of the target volume for each treatment fraction. Using the concept of target registration error (TRE), the performance of several methods of target localization was compared. Methods and Materials Twelve patients who underwent external beam accelerated partial breast irradiation were included in this study. TRE was quantified for four methods of image guidance: standard laser-based setup, kilovoltage Imaging of the chest wall, kilovoltage Imaging of surgically implanted clips, and three-dimensional Surface Imaging of the breast. The use of a reference Surface created from a free-breathing computed tomography scan and a reference Surface directly captured with three-dimensional video Imaging were compared. The effects of respiratory motion were also considered, and gating was used for 8 of 12 patients. Results The median value of the TRE for the laser, chest wall, and clip alignment was 7.1 mm ( n = 94), 5.4 mm ( n = 81), and 2.4 mm ( n = 93), respectively. The median TRE for gated Surface Imaging based on the first fraction reference Surface was 3.2 mm ( n = 49), and the TRE for gated Surface Imaging using the computed tomography-based reference Surface was 4.9 mm ( n = 56). The TRE for nongated Surface Imaging using the first fraction reference Surface was 6.2 mm ( n = 25). Conclusions The TRE of Surface Imaging using a reference Surface directly captured with three-dimensional video and the TRE for clip-based setup were within 1 mm. Gated capture is important for Surface Imaging to reduce the effects of respiratory motion in accelerated partial breast irradiation.