Dr. Sanjiv S. Samant Profile

Dr. Sanjiv S. Samant

Associate Professor at Univ of Florida

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Publications (14)

Proceedings Article | 28 September 2011 Paper

Prototype high detective quantum efficiency imaging panel based on a fiber-optic scintillation glass array (FOSGA) for megavoltage imaging

Sanjiv Samant, Jim Baciak, Arun Gopal

Proceedings Volume 8142, 81420P (2011) https://doi.org/10.1117/12.896946

KEYWORDS: Sensors, Optical fibers, Prototyping, Imaging systems, Scintillation, Scintillators, Modulation transfer functions, Quantum efficiency, Glasses, X-rays

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Proceedings Article | 19 March 2007 Paper

The Juggler algorithm: a hybrid deformable image registration algorithm for adaptive radiotherapy

Junyi Xia, Yunmei Chen, Sanjiv Samant

Proceedings Volume 6510, 65105J (2007) https://doi.org/10.1117/12.713693

KEYWORDS: Image registration, Radiotherapy, Detection and tracking algorithms, Diffusion, 3D modeling, 4D CT imaging, Computed tomography, Tissues, Motion models, Computer simulations

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Proceedings Article | 15 March 2007 Paper

A new paradigm in portal imaging QA: fast measurements of modulation transfer function (MTF) and detective quantum efficiency (DQE) using line-pair bar patterns

Arun Gopal, Sanjiv Samant

Proceedings Volume 6510, 651048 (2007) https://doi.org/10.1117/12.713704

KEYWORDS: Modulation transfer functions, Image quality, Sensors, Modulation, Spatial resolution, Imaging systems, Spatial frequencies, Quantum efficiency, Amorphous silicon, Video

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Proceedings Article | 12 May 2004 Paper

Registration quality evaluator: application to automated patient setup verification in radiotherapy

Jian Wu, Sanjiv Samant

Proceedings Volume 5370, (2004) https://doi.org/10.1117/12.538080

KEYWORDS: Image registration, Radiotherapy, Image quality, Tolerancing, Receivers, Statistical analysis, Reliability, Biomedical engineering, Image analysis, Imaging devices

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Proceedings Article | 5 June 2003 Paper

Bar-pattern technique for modulation transfer function measurement in portal imaging

Arun Gopal, Sanjiv Samant

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.482400

KEYWORDS: Modulation transfer functions, Monte Carlo methods, Lead, Spatial frequencies, Sensors, Modulation, Imaging systems, Prototyping, Data acquisition, X-rays

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Proceedings Article | 5 June 2003 Paper

Study of the detective quantum efficiency for the kinestatic charge detector as a megavoltage imaging device

Sanjiv Samant, Arun Gopal, Frank DiBianca

Proceedings Volume 5030, (2003) https://doi.org/10.1117/12.482402

KEYWORDS: Modulation transfer functions, Monte Carlo methods, Sensors, Imaging systems, Prototyping, Quantum efficiency, Spatial resolution, Xenon, Signal to noise ratio, Spatial frequencies

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Proceedings Article | 28 May 1999 Paper

Spectral response of CsI(Tl) transparent scintillation detector for megavoltage imaging

Sanjiv Samant, Herbert Zeman, Brent Weinberg, Wei Zheng, Pradeep Patra

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349560

KEYWORDS: Scintillators, Spatial resolution, Imaging systems, CCD cameras, Modulation transfer functions, Aluminum, X-rays, Cameras, Charge-coupled devices, Signal attenuation

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In megavoltage imaging, current commercial electronic portal imaging devices (EPIDs), despite having the advantage of immediate digital imaging over film, suffer from poor image contrast and spatial resolution. In a previous paper, a prototype megavoltage portal imaging system was described that utilized a 3 mm thick 100 mm field of view CsI (Tl) transparent scintillating crystal (corresponding to a radiological thickness of 1350 mg/cm²) coupled to a liquid nitrogen cooled slow-scan CCD camera with a combination of two camera lenses to yield a 42 mm f1.0 macro lens and a 5:1 demagnification. The imaging display significantly superior contrast and spatial resolutions (1 lp/mm at 20% MTF) to that available from the commercial EPIDs, which typically consist of a CCD camera coupled to a relatively thin gadolinium oxysulfide screen (with a radiological thickness of 400 mg/cm²). However it required significantly higher dose than portal film. Subsequent effort has focused on optimization of the optics and scintillator thickness in order to reduce the required imaging dose, while still providing superior image and contrast resolutions to that of the commercial EPIDs. Improved images were acquired using a two- camera lens combination yielding a 50 mm f1.1 macro lens with a 7:1 demagnification. Subsequently, portal imaging with an even thicker 13 mm CsI(Tl) scintillator (corresponding to a radiological thickness of 5850 mg/cm²) was carried out. An increase in scintillator thickness was accompanied by only a small loss in spatial resolution (1 lp/mm at 17% MTF) by optimizing the optical geometry. The image quality was significantly superior to that of the commercial EPIDs (Elekta SRI-100 and Siemens BEAMVIEW), and comparable to that for portal film, while requiring an imaging dose that was less than or comparable to that for film or the EPIDs. The purpose of this research is to investigate the effect of spectral shifting and buildup material or imaging for this prototype system. The use of clear thick single crystal scintillators is relatively new in portal imaging. Early work on optimization of CCD based EPIDs dealt primarily with amorphous nontransparent scintillators, and the use of thick scintillators was abandoned due to a clinically unacceptable associated loss in spatial resolution. Optimization of CCD based EPIDs has been implicitly based on the use of thin scintillators. This recent imaging success of the CsI(Tl) scintillator CCD camera based system utilizing a relatively thick scintillator offers a possibly superior alternative to the current CCD based systems. This superior imaging was accomplished in the absence of any optimization dealing with the choice of buildup material or thickness. Such optimization presents the potential for further gains in imaging quality. Experimental results dealing with optimization of scintillator thickness and buildup plate thickness and material are presented. The effect on image quality due to a spectral shift in a 6 MV photon beam in the presence of phantom scatter is discussed.

Proceedings Article | 28 May 1999 Paper

New calibration technique for KCD-based megavoltage imaging

Sanjiv Samant, Wei Zheng, Frank DiBianca, Herbert Zeman, Joseph Laughter

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349559

KEYWORDS: Calibration, Signal to noise ratio, Imaging systems, Spatial resolution, Sensors, Data acquisition, Modulation transfer functions, X-rays, Digital imaging, Prototyping

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In megavoltage imaging, current commercial electronic portal imaging devices (EPIDs), despite having the advantage of immediate digital imaging over film, suffer from poor image contrast and spatial resolution. The feasibility of using a kinestatic charge detector (KCD) as an EPID to provide superior image contrast and spatial resolution for portal imaging has already been demonstrated in a previous paper. The KCD system had the additional advantage of requiring an extremely low dose per acquired image, allowing for superior imaging to be reconstructed form a single linac pulse per image pixel. The KCD based images utilized a dose of two orders of magnitude less that for EPIDs and film. Compared with the current commercial EPIDs and film, the prototype KCD system exhibited promising image qualities, despite being handicapped by the use of a relatively simple image calibration technique, and the performance limits of medical linacs on the maximum linac pulse frequency and energy flux per pulse delivered. This image calibration technique fixed relative image pixel values based on a linear interpolation of extrema provided by an air-water calibration, and accounted only for channel-to-channel variations. The counterpart of this for area detectors is the standard flat fielding method. A comprehensive calibration protocol has been developed. The new technique additionally corrects for geometric distortions due to variations in the scan velocity, and timing artifacts caused by mis-synchronization between the linear accelerator and the data acquisition system (DAS). The role of variations in energy flux (2 - 3%) on imaging is demonstrated to be not significant for the images considered. The methodology is presented, and the results are discussed for simulated images. It also allows for significant improvements in the signal-to- noise ratio (SNR) by increasing the dose using multiple images without having to increase the linac pulse frequency or energy flux per pulse. The application of this protocol to a KCD system under construction is expected shortly.

Proceedings Article | 28 May 1999 Paper

Human subject portal images with a Csl(Tl) transparent scintillator

Herbert Zeman, Sanjiv Samant, Amit Sawant

Proceedings Volume 3659, (1999) https://doi.org/10.1117/12.349548

KEYWORDS: Imaging systems, Spatial resolution, X-rays, Cameras, CCD cameras, X-ray imaging, Crystals, Scintillators, Charge-coupled devices, Modulation transfer functions

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Proceedings Article | 21 May 1999 Paper

Adaptive median filter algorithm to remove impulse noise in x-ray and CT images and speckle in ultrasound images

Amit Sawant, Herbert Zeman, Diane Muratore, Sanjiv Samant, Frank DiBianca

Proceedings Volume 3661, (1999) https://doi.org/10.1117/12.348522

KEYWORDS: Digital filtering, Image filtering, Speckle, X-ray imaging, Ultrasonography, Image processing, X-rays, Optical filters, Image resolution, X-ray computed tomography

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Proceedings Article | 24 July 1998 Paper

Development of portal CT reconstruction using MLS-ART technique and the kinestatic charge detector imaging system: I. Low-energy x-ray studies

M. Waleed Gaber, Huaiqun Guan, Frank DiBianca, Sanjiv Samant, Yunping Zhu

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317077

KEYWORDS: Sensors, Reconstruction algorithms, X-ray computed tomography, X-rays, CT reconstruction, X-ray detectors, Computed tomography, Imaging systems, Image sensors, Diagnostics

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Proceedings Article | 24 July 1998 Paper

Portal imaging with a CsI(Tl) transparent scintillator x-ray detector

Herbert Zeman, Sanjiv Samant, Gunnar Lovhoiden, Brent Weinberg, Amit Sawant

Proceedings Volume 3336, (1998) https://doi.org/10.1117/12.317015

KEYWORDS: Imaging systems, Spatial resolution, X-rays, CCD cameras, Scintillators, Cameras, Crystals, X-ray imaging, X-ray detectors, Energy efficiency

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Proceedings Article | 2 May 1997 Paper

6-MVp x-ray imaging with a transparent scintillator x-ray detector

Herbert Zeman, Sanjiv Samant, Jacob Rasmussen

Proceedings Volume 3032, (1997) https://doi.org/10.1117/12.274006

KEYWORDS: X-rays, Charge-coupled devices, Scintillators, Imaging systems, CCD cameras, X-ray imaging, Composites, Cameras, Ceramics, Image resolution

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Proceedings Article | 2 May 1997 Paper

Use of a kinestatic charge detector for megavoltage portal imaging

Frank DiBianca, Sanjiv Samant, Joseph Laughter, Jacob Rasmussen, Carlos Rodriguez

Proceedings Volume 3032, (1997) https://doi.org/10.1117/12.273985

KEYWORDS: Imaging systems, Monte Carlo methods, Sensors, Modulation transfer functions, Spatial resolution, Energy efficiency, Image quality, Quantum efficiency, X-rays, Image resolution

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Showing 5 of 14 publications

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