Anuj J Kapadia
Assistant Professor in the Department of Radiology
1) Experimental Implementation of NSECT
Neutron spectroscopy techniques are showing significant promise in determining element concentrations in the human body. We have developed a tomographic imaging system capable of generating tomographic images of the element concentration within a body through a single non-invasive in-vivo scan. This system has been implemented using a Van-de-Graaf accelerator fast neutron source and high-purity germanium gamma detectors at the Triangle Universities Nuclear Laboratory. This setup has been used to obtain NSECT scans for several samples such as bovine liver, mouse specimens and human breast tissue. In order to extract maximum information about a target sample with the lowest possible levels of dose, it is essential to maximize the sensitivity of the scanning system. In other words, the signal to noise ratio for the experimental setup must be maximized. This project aims at increasing the sensitivity of the NSECT system by understanding the various sources of noise and implementing techniques to reduce their effect. Noise in the system may originate from several factors such as the radiative background in the scanning room, and neutron scatter off of components of the system other than the target. Some of these effects can be reduced by using Time-of-Flight background reduction, while others can be reduced by acquiring a separate sample-out scan. Post processing background reduction techniques are also being developed for removing detector efficiency dependent noise. At this point we have acquired element information from whole mouse specimens and iron-overloaded liver models made of bovine liver tissue artificially injected with iron. Tomographic images have been generated from a solid iron and copper phantom. Our final goal is to implement a low-dose non-invasive scanning system for diagnosis of iron overload and breast cancer.
2) Monte-Carlo simulations in GEANT4
For each tomographic scan of a sample using NSECT, there are several acquisition parameters that can be varied. These parameters can broadly be classified into three categories: (i) Neutron Beam parameters: neutron flux, energy and beam width, (ii) Detector parameters: detector type, size, efficiency and location; (iii) Scanning Geometry: spatial and angular sampling rates. Due to the enormous number of combinations possible using these parameters, it is not feasible to investigate the effects of each parameter on the reconstructed image using a real neutron beam in the limited beam time available. A feasible alternative to this is to use Monte-Carlo simulations to reproduce the entire experiment in a virtual world. The effect of each individual parameter can then be studied using only computer processing time and resources. We use the high energy physics Monte-Carlo software package GEANT4, developed by CERN, which incorporates numerous tools required for building particle sources and detectors, and tracking particle interactions within them. The simulations built so far include the neutron source, HPGE and BGO gamma detectors, and several target materials such as iron, liver and breast tissue.
Simulation Tools for 3D and 4D CT and Dosimetry awarded by National Institutes of Health (Investigator). 2007 to 2018
Characterizing, modeling, and mitigating texturing in X-ray diffraction imaging awarded by Northeastern University (Co-Principal Investigator). 2017 to 2018
International Workshop on the Next Generation Gamma-ray Sources awarded by Department of Energy (Co-Principal Investigator). 2015 to 2017
Cross-disciplinary Training in Medical Physics awarded by National Institutes of Health (Mentor). 2007 to 2013
Stimulation to Evaluate Accuracy and Patient Dose in Neutron Stimulated Emission Computed Tomography (NSECT) awarded by United States Army Medical Research and Materiel Command (PI-Fellow). 2006 to 2009
Breast Elemental Composition Imaging awarded by National Institutes of Health (Graduate Student). 2004 to 2007
Lakshmanan, MN, Greenberg, JA, Samei, E, and Kapadia, AJ. "Accuracy assessment and characterization of x-ray coded aperture coherent scatter spectral imaging for breast cancer classification." Journal of medical imaging (Bellingham, Wash.) 4.1 (January 2017): 013505-. Full Text
Lakshmanan, MN, Greenberg, JA, Samei, E, and Kapadia, AJ. "Design and implementation of coded aperture coherent scatter spectral imaging of cancerous and healthy breast tissue samples." Journal of medical imaging (Bellingham, Wash.) 3.1 (January 2016): 013505-. Full Text
Odinaka, I, O'Sullivan, JA, Politte, DG, MacCabe, KP, Kaganovsky, Y, Greenberg, JA, Lakshmanan, MN, Krishnamurthy, K, Kapadia, AJ, Carin, L, and Brady, DJ. "Joint System and Algorithm Design for Computationally Efficient Fan Beam Coded Aperture X-ray Coherent Scatter Imaging." CoRR abs/1603.06400 (2016).
Lakshmanan, MN, Harrawood, BP, Samei, E, and Kapadia, AJ. "Volumetric x-ray coherent scatter imaging of cancer in resected breast tissue: a Monte Carlo study using virtual anthropomorphic phantoms." Physics in medicine and biology 60.16 (August 3, 2015): 6355-6370. Full Text
Lakshmanan, MN, Harrawood, BP, Rusev, G, Agasthya, GA, and Kapadia, AJ. "Simulations of nuclear resonance fluorescence in Geant4." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 763 (November 2014): 89-96. Full Text
Harrawood, BP, Agasthya, GA, Lakshmanan, MN, Raterman, G, and Kapadia, AJ. "Geant4 distributed computing for compact clusters." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 764 (November 2014): 11-17. Full Text
Lakshmanan, MN, Kapadia, AJ, Sahbaee, P, Wolter, SD, Harrawood, BP, Brady, D, and Samei, E. "An X-ray scatter system for material identification in cluttered objects: A Monte Carlo simulation study." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 335 (September 2014): 31-38. Full Text
Belley, MD, Segars, WP, and Kapadia, AJ. "Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver." Medical physics 41.6 (June 2014): 063902-. Full Text
Lakshmanan, MN, Harrawood, BP, Agasthya, GA, and Kapadia, AJ. "Simulations of breast cancer imaging using gamma-ray stimulated emission computed tomography." IEEE transactions on medical imaging 33.2 (February 2014): 546-555. Full Text
Lakshmanan, MN, Kapadia, AJ, Harrawood, BP, Brady, D, and Samei, E. "X-ray coherent scatter imaging for surgical margin detection: A Monte Carlo study." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 9033 (January 1, 2014). Full Text
Hoye, J, Zhang, Y, Agasthya, G, Sturgeon, G, Kapadia, A, Segars, WP, and Samei, E. "An atlas-based organ dose estimator for tomosynthesis and radiography." January 1, 2017. Full Text
Spencer, JR, Carter, JE, Leung, CK, McCall, SJ, Greenberg, JA, and Kapadia, AJ. "Coded aperture coherent scatter spectral imaging for assessment of breast cancers: An ex-vivo demonstration." January 1, 2017. Full Text
Fu, W, Sturgeon, GM, Agasthya, G, Segars, WP, Kapadia, AJ, and Samei, E. "Estimation of breast dose reduction potential for organ-based tube current modulated CT with wide dose reduction arc." January 1, 2017. Full Text
Abadi, E, Sturgeon, GM, Agasthya, G, Harrawood, B, Hoeschen, C, Kapadia, A, Segars, WP, and Samei, E. "Airways, vasculature, and interstitial tissue: Anatomically informed computational modeling of human lungs for virtual clinical trials." January 1, 2017. Full Text
Lakshmanan, MN, Morris, RE, Greenberg, JA, Samei, E, and Kapadia, AJ. "Coded aperture coherent scatter imaging for breast cancer detection: A Monte Carlo evaluation." January 1, 2016. Full Text
Morris, RE, Albanese, KE, Lakshmanan, MN, McCall, SJ, Greenberg, JA, and Kapadia, AJ. "Validation of coded aperture coherent scatter spectral imaging for normal and neoplastic breast tissues via surgical pathology." January 1, 2016. Full Text
Greenberg, JA, Lakshmanan, MN, Brady, DJ, and Kapadia, AJ. "Optimization of a coded aperture coherent scatter spectral imaging system for medical imaging." January 1, 2015. Full Text
Lakshmanan, MN, Greenberg, JA, Samei, E, and Kapadia, AJ. "Experimental implementation of coded aperture coherent scatter spectral imaging of cancerous and healthy breast tissue samples." January 1, 2015. Full Text
Kapadia, AJ, Gallmeier, FX, Iverson, EB, Ferguson, PD, and IEEE, . "Detection of Iron Overload with the ORNL Spallation Neutron Source: an MCNPX Simulation Study." 2009.