Dr. Moiz U. Ahmad Profile

Dr. Moiz U. Ahmad

at Univ of Texas MD Anderson Cancer Center

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Publications (6)

SPIE Journal Paper | 22 August 2024

Cone-beam CT with a noncircular (sine-on-sphere) orbit: imaging performance of a clinical system for image-guided interventions

A. Kyle Jones, Moiz Ahmad, Shaan Raza, Stephen Chen, Jeffrey H. Siewerdsen

JMI, Vol. 11, Issue 04, 043503, (August 2024) https://doi.org/10.1117/12.10.1117/1.JMI.11.4.043503

KEYWORDS: Modulation transfer functions, Imaging systems, Cone beam computed tomography, Computed tomography, Image quality, Head, Spatial resolution, Skull, Reconstruction algorithms, Voxels

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PurposeWe aim to compare the imaging performance of a cone-beam CT (CBCT) imaging system with noncircular scan protocols (sine-on-sphere) to a conventional circular orbit.ApproachA biplane C-arm system (ARTIS Icono; Siemens Healthineers) capable of circular and noncircular CBCT acquisition was used, with the latter orbit (sine-on-sphere, “Sine Spin”) executing a sinusoidal motion with ±10 deg tilt amplitude over the half-scan orbit. A test phantom was used for the characterization of image uniformity, noise, noise-power spectrum (NPS), spatial resolution [modulation transfer function (MTF) in axial and oblique directions], and cone-beam artifacts. Findings were interpreted using an anthropomorphic head phantom with respect to pertinent tasks in skull base neurosurgery.ResultsThe noncircular scan protocol exhibited several advantages associated with improved 3D sampling—evident in the NPS as filling of the null cone about the fz spatial frequency axis and reduction of cone-beam artifacts. The region of support at the longitudinal extrema was reduced from 16 to ∼12 cm at a radial distance of 6.5 cm. Circular and noncircular orbits exhibited nearly identical image uniformity and quantum noise, demonstrating cupping of −16.7% and overall noise of ∼27 HU. Although both the radially averaged axial MTF (fx,y) and 45 deg oblique MTF (fx,y,z) were ∼20% lower for the noncircular orbit compared with the circular orbit at the default full reconstruction field of view (FOV), there was no difference in spatial resolution for the medium reconstruction FOV (smaller voxel size). Differences in the perceptual image quality for the anthropomorphic phantom reinforced the objective, quantitative findings, including reduced beam-hardening and cone-beam artifacts about structures of interest in the skull base.ConclusionsImage quality differences between circular and noncircular CBCT orbits were quantitatively evaluated on a clinical system in the context of neurosurgery. The primary performance advantage for the noncircular orbit was the improved sampling and elimination of cone-beam artifacts.

Proceedings Article | 7 May 2024 Presentation + Paper

Patient-specific NEQ(f): automatic local and global determination of spatial-frequency-dependent SNR and task performance in clinical CT

Parvathy Pillai, Jeffrey Siewerdsen, Tatiana Rypinski, Anshuj Deva, Bhavin Soni, A. Kyle Jones, Moiz Ahmad

Proceedings Volume 12925, 1292517 (2024) https://doi.org/10.1117/12.3008465

KEYWORDS: Modulation transfer functions, Computed tomography, Image quality, Quality control, Imaging systems, Spatial resolution, Signal detection, Cancer, Abdomen, 3D image processing

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Proceedings Article | 7 April 2023 Presentation + Paper

Cone-beam CT with a noncircular (sine-on-sphere) orbit: imaging performance of a clinical system for image-guided interventions

A. Kyle Jones, Moiz Ahmad, Shaan Raza, Stephen Chen, Jeffrey Siewerdsen

Proceedings Volume 12463, 1246313 (2023) https://doi.org/10.1117/12.2654347

KEYWORDS: Imaging systems, Cone beam computed tomography, Image quality, Computed tomography, Image guided intervention, Head, Voxels, Quantum sampling

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Proceedings Article | 17 March 2011 Paper

Four-dimensional volume-of-interest reconstruction for cone-beam computerized tomography based image-guided radiation therapy of the lung

Moiz Ahmad, Tinsu Pan

Proceedings Volume 7961, 79615R (2011) https://doi.org/10.1117/12.878919

KEYWORDS: Lung, Tumors, Computed tomography, Radiotherapy, Temporal resolution, Tomography, 3D modeling, 3D image processing, Optical spheres, Composites

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Proceedings Article | 16 March 2011 Paper

Optimization of four-dimensional cone-beam computed tomography in image-guided radiation therapy of the lung

Moiz Ahmad, Tinsu Pan

Proceedings Volume 7961, 79615T (2011) https://doi.org/10.1117/12.878902

KEYWORDS: Image quality, Radiotherapy, Lung, Computer simulations, Tumors, Computed tomography, Temporal resolution, Imaging systems, Image quality standards, X-ray computed tomography

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Proceedings Article | 11 March 2009 Paper

Optimization of 4D cone-beam CT: evaluation of streaking artifacts and noise with various simulated gantry rotation speeds

Moiz Ahmad, Peter Balter, Peter Munro, Jun Lu, Tinsu Pan

Proceedings Volume 7258, 725808 (2009) https://doi.org/10.1117/12.813739

KEYWORDS: Signal to noise ratio, Image quality, Imaging systems, Radiotherapy, Tumors, Computer simulations, Computed tomography, Data acquisition, Visualization, Sensors

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