Download or read book Development of a Fan beam Optical Computed Tomography Scanner for Three dimensional Dosimetry written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The current state of a prototype fan-beam optical computed tomography scanner for three-dimensional radiation dosimetry has been presented. The system uses a helium-neon laser and a line-generating lens for fan-beam creation. Five photodiode arrays form an approximate arc detector array of 320-elements. Two options of physical collimators provide two levels of scatter-rejection: single-slot (SS) and multi-hole (MH). A pair of linear polarizers has been introduced as a means of light intensity modulation. This work examined: (i) the characterization of system components, (ii) data acquisition & imaging protocols, and (iii) the scanning of an nPAG dosimeter. (i): The polarizer-pair method of light intensity modulation has been calibrated and the polarization sensitivity of the detector array was evaluated. The relationship between detected values and both light intensity and photodiode integration time was examined. This examination indicated the need for an offset correction to treat all data acquired by the system. Data corruption near the edges of each photodiode array was found to cause ring artefacts in image reconstructions. Two methods of extending the dynamic range of the system---via integration time and light intensity---were presented. The use of master absorbent solutions and spectrophotometric data allowed for the preparation of absorption-based and scatter-based samples of known opacities. This ability allowed for the evaluation of the relative scatter-rejection capabilities of the system's two collimators. The MH collimator accurately measured highly-attenuating solutions of both absorption-based and scatter-based agents. The SS collimator experienced some contamination by scattered light with absorption-based agents, and significant contamination with scatter-based agents. Also, using the SS collimator, a `spiking' artefact was observed in highly-attenuating samples of both solution types. (ii): A change in imaging protocol has been described that grea.
Download or read book Development of a Fan beam Optical Computed Tomography Scanner for Three dimensional Dosimetry written by Warren Gerard Campbell and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The current state of a prototype fan-beam optical computed tomography scanner for three-dimensional radiation dosimetry has been presented. The system uses a helium-neon laser and a line-generating lens for fan-beam creation. Five photodiode arrays form an approximate arc detector array of 320-elements. Two options of physical collimators provide two levels of scatter-rejection: single-slot (SS) and multi-hole (MH). A pair of linear polarizers has been introduced as a means of light intensity modulation. This work examined: (i) the characterization of system components, (ii) data acquisition & imaging protocols, and (iii) the scanning of an nPAG dosimeter. (i): The polarizer-pair method of light intensity modulation has been calibrated and the polarization sensitivity of the detector array was evaluated. The relationship between detected values and both light intensity and photodiode integration time was examined. This examination indicated the need for an offset correction to treat all data acquired by the system. Data corruption near the edges of each photodiode array was found to cause ring artefacts in image reconstructions. Two methods of extending the dynamic range of the system--via integration time and light intensity--were presented. The use of master absorbent solutions and spectrophotometric data allowed for the preparation of absorption-based and scatter-based samples of known opacities. This ability allowed for the evaluation of the relative scatter-rejection capabilities of the system's two collimators.
Download or read book Prototype Fan Beam Optical Computed Tomography Scanner for Three dimensional Radiotherapy Dose Verification written by David Rudko and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A prototype rapid, high precision fan beam optical computed tomography (OptCT) scanner for three-dimensional polymer gel dosimetry of complex radiotherapy protocols has been developed. This study documents the design. construction and characterization of the system, as well as preliminary reconstructed optical attenuation images and dosimetric verification experiments. The principal goal in scanner design and implementation was to satisfy the Radiotherapy Accuracy and Precision (RTAP) criteria consisting of a spatial resolution of 1 x 1 x 1 mm3, an imaging time of 60 minutes, a dose accuracy within 3% and a precision within 1%. The scanner, which employs a sixty degree fan beam of 543 nm laser light to scan irradiated polymer gel samples up to 19 cm in cross-sectional diameter. has several defining attributes. Data acquisition for a single slice through a dosimeter is achieved in two minutes, using one signal acquisition per CT projection angle over a total of 360 projections. The effects of scatter and refraction of visible light are minimized by using the unique radial design of the matching medium tank, the concentric arrangement of a prototype, computer numerical control (CNC)-machined collimator and five Hamamatsu photodiode detector arrays for light detection. The novel tertiary collimation eliminates scattered light by 13% and improves reconstructed image contrast-to-noise ratio. Other characteristics of the scanner include: a laser power output variation of only 0.7%:, signal-to-noise ratio (SNR.) for calibration projections of up to 294:1, SNR for transmission projections through an irradiated polymer gel dosimeter of up to 161:1, a large absorbance dynamic range extending from 0.1 to 1.7 absorbance units and a spatial resolution of 0.25 mm2 in the axial plane of the scan?ning geometry and 0.8 mm along the longitudinal z-axis of the scan plane. Images of optical attenuation coefficients and concomitant dose maps extracted from irradi?ated, normoxic N--isopropylacylamide (NIPAM) polymer gels were used to investigate the potential of the system for dosimetric verification. Three different NIPAM gel irradiation experiments were performed and the resultant OptCT dose distributions were compared to the Eclipse? (Varian Medical Systems. Palo Alto. CA.) treatment planning system model. While the fan beam OptCT scanner provides promising ini?tial images of reconstructed optical attenuation coefficients, its dosimetric accuracy compared to Eclipse - nominally 7% in low dose gradient regions and 5% on the field edges - constitutes the most significant area for future refinement.
Download or read book Enabling Industry 4 0 through Advances in Mechatronics written by Ismail Mohd. Khairuddin and published by Springer Nature. This book was released on 2022-05-14 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents part of the iM3F 2021 proceedings from the mechatronics track. It highlights key challenges and recent trends in mechatronics engineering and technology that are non-trivial in the age of Industry 4.0. It discusses traditional as well as modern solutions that are employed in the multitude spectra of mechatronics-based applications. The readers are expected to gain an insightful view on the current trends, issues, mitigating factors as well as solutions from this book.
Download or read book Development of Three dimensional Ex Vivo Optical Imaging written by Angela Maria D'Esposito and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Specification and Acceptance Testing of Computed Tomography Scanners written by American Association of Physicists in Medicine. Diagnostic X-Ray Imaging Committee and published by . This book was released on 1993 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrotechnology for Development written by and published by . This book was released on 1981 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three dimensional Cone beam Computed Tomography ActiveX Style written by Stefano Agostinelli (fisico.) and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of an Intelligent Three Dimensional Optical Inspection System written by Chan-Teh Kuo and published by . This book was released on 1999 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MDCT written by Mannudeep K. Kalra and published by Springer Science & Business Media. This book was released on 2009-11-16 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: "MDCT: From Protocols to Practice" tackles contemporary and topical issues in MDCT technology and applications. As an updated edition of MDCT: A Practical Approach, this volume offers new content as well as revised chapters from the previous volume. New chapters discuss important topics such as imaging of children and obese subjects, the use of contrast medium in pregnant women, coronary MDCT angiography, and PET/CT in abdominal and pelvic malignancies. Furthermore an Appendix with over 50 updated MDCT scanning protocols completes this publication. The book emphasizes the practical aspects of MDCT, making it an invaluable source of information for radiologists, residents, medical physicists, and radiology technologists in everyday clinical practice.
Download or read book Index Medicus written by and published by . This book was released on 2004 with total page 1780 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Download or read book Proceedings of MELECON written by and published by . This book was released on with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combined fan beam parallel beam scanning in high resolution computed tomography written by Yeong-Ho Ha and published by . This book was released on 1985 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three dimensional Reconstruction from Cone beam Projections for Flat and Curved Detectors written by Hui Hu and published by . This book was released on 1989 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fan beam Computed Tomography written by Martin Joel Yaffe and published by c1978.. This book was released on 1978 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multispectral Three dimensional Optical Coherence Tomography written by Aneesh Alex and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Redesign of a Three dimensional Laser Scanner and Development of a Focus based Ranging System written by Ronald M. Pasquini and published by . This book was released on 1996 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
