Mr. Brent D. Weinberg Profile

Brent D. Weinberg

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Publications (5)

Proceedings Article | 30 May 2003 Paper

3D parametric model of lesion geometry for evaluation of MR-guided radiofrequency ablation therapy

Roee Lazebnik, Brent Weinberg, Michael Breen, Jonathan Lewin, David Wilson

Proceedings Volume 5029, (2003) https://doi.org/10.1117/12.479759

KEYWORDS: Image segmentation, 3D modeling, Magnetic resonance imaging, Tissues, In vivo imaging, Data modeling, Animal model studies, Visual process modeling, Electrodes, Natural surfaces

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Proceedings Article | 15 May 2003 Paper

Automatic model-based 3D lesion segmentation for evaluation of MR-guided thermal ablation therapy

Roee Lazebnik, Brent Weinberg, Michael Breen, Jonathan Lewin, David Wilson

Proceedings Volume 5032, (2003) https://doi.org/10.1117/12.481385

KEYWORDS: Image segmentation, 3D modeling, Magnetic resonance imaging, Tissues, Electrodes, In vivo imaging, Visualization, Data modeling, Animal model studies, Thermal modeling

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Proceedings Article | 2 May 2003 Paper

Characterization of tissue response to radiofrequency ablation using 3D model-based analysis of interventional MR images

Brent Weinberg, Roee Lazebnik, Michael Breen, Jonathan Lewin, David Wilson

Proceedings Volume 5031, (2003) https://doi.org/10.1117/12.480414

KEYWORDS: Image segmentation, 3D modeling, Tissues, Magnetic resonance imaging, Electrodes, 3D image processing, In vivo imaging, Laser ablation, Data modeling, Radiofrequency ablation

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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 | 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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