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Papers by Mitchell Sommerville

Research paper thumbnail of TU-F-CAMPUS-I-02: Validation of a CT X-Ray Source Characterization Technique for Dose Computation Using An Anthropomorphic Thorax Phantom

Medical Physics, 2015

ABSTRACT

Research paper thumbnail of Sci-Thur AM: YIS - 09: Validation of a General Empirically-Based Beam Model for kV X-ray Sources

Medical Physics, 2014

A floristic survey of Cholistan desert was carried out during 2009-2011 and total of 38 families,... more A floristic survey of Cholistan desert was carried out during 2009-2011 and total of 38 families, 106 genera and 154 species were documented from the area. Among families, 33 families belong to Dicotyledons of 79 genera and 115 species, while the 38 species of 26 genera belong to 4 families of Monocotyledons and 1 family of gymnosperms with 1 genus and 1 species. The largest family was Poaceae with 34 species followed by Papilionaceae and Zygophyllaceae with 10 species while Asteraceae with 9 species respectively. The life form of plant species was determined by following the Raunkier's method. Therophytes comprised of 74 species (48%), Chamaephyte 40 species (26%), Hemicryptophyte 18 species (12%), Phanerophyte 19 species (12%) and Cryptophyte 3 species (2%) of the flroa of the area. It will be helpful and serve for the conservation and sustainable utilization of plant resources of the study area.

Research paper thumbnail of MO-D-134-10: Using HVL and KVp to Portray An X-Ray Source for Dose Calculations in CT

Medical Physics, 2013

ABSTRACT

Research paper thumbnail of A measurement-based X-ray source model characterization for CT dosimetry computations

Journal of applied clinical medical physics, 2015

The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and meas... more The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and measured half-value layer (HVL) can be used to generate energy spectra and fluence profiles for characterizing a computed tomography (CT) X-ray source, and to validate the source model and an in-house kV X-ray dose computation algorithm (kVDoseCalc) for computing machine- and patient-specific CT dose. Spatial variation of the X-ray source spectra of a Philips Brilliance and a GE Optima Big Bore CT scanner were found by measuring the HVL along the direction of the internal bow-tie filter axes. Third-party software, Spektr, and the nominal kVp settings were used to generate the energy spectra. Beam fluence was calculated by dividing the integral product of the spectra and the in-air NIST mass-energy attenuation coefficients by in-air dose measurements along the filter axis. The authors found the optimal number of photons to seed in kVDoseCalc to achieve dose convergence. The Philips Brilliance...

Research paper thumbnail of An Experimental X-Ray Source Characterization Method for Computed Tomography (CT) Dosimetry Simulations

Research paper thumbnail of A measurement-based X-ray source model characterization for CT dosimetry computations

Journal of applied clinical medical physics / American College of Medical Physics, Jan 8, 2015

The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and meas... more The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and measured half-value layer (HVL) can be used to generate energy spectra and fluence profiles for characterizing a computed tomography (CT) X-ray source, and to validate the source model and an in-house kV X-ray dose computation algorithm (kVDoseCalc) for computing machine- and patient-specific CT dose. Spatial variation of the X-ray source spectra of a Philips Brilliance and a GE Optima Big Bore CT scanner were found by measuring the HVL along the direction of the internal bow-tie filter axes. Third-party software, Spektr, and the nominal kVp settings were used to generate the energy spectra. Beam fluence was calculated by dividing the integral product of the spectra and the in-air NIST mass-energy attenuation coefficients by in-air dose measurements along the filter axis. The authors found the optimal number of photons to seed in kVDoseCalc to achieve dose convergence. The Philips Brilliance...

Research paper thumbnail of TU-F-CAMPUS-I-02: Validation of a CT X-Ray Source Characterization Technique for Dose Computation Using An Anthropomorphic Thorax Phantom

Medical Physics, 2015

ABSTRACT

Research paper thumbnail of MO-D-134-10: Using HVL and KVp to Portray An X-Ray Source for Dose Calculations in CT

Medical Physics, 2013

ABSTRACT

Research paper thumbnail of Sci—Thur AM: YIS - 09: Validation of a General Empirically-Based Beam Model for kV X-ray Sources

Medical Physics, 2014

ABSTRACT

Research paper thumbnail of TU-F-CAMPUS-I-02: Validation of a CT X-Ray Source Characterization Technique for Dose Computation Using An Anthropomorphic Thorax Phantom

Medical Physics, 2015

ABSTRACT

Research paper thumbnail of Sci-Thur AM: YIS - 09: Validation of a General Empirically-Based Beam Model for kV X-ray Sources

Medical Physics, 2014

A floristic survey of Cholistan desert was carried out during 2009-2011 and total of 38 families,... more A floristic survey of Cholistan desert was carried out during 2009-2011 and total of 38 families, 106 genera and 154 species were documented from the area. Among families, 33 families belong to Dicotyledons of 79 genera and 115 species, while the 38 species of 26 genera belong to 4 families of Monocotyledons and 1 family of gymnosperms with 1 genus and 1 species. The largest family was Poaceae with 34 species followed by Papilionaceae and Zygophyllaceae with 10 species while Asteraceae with 9 species respectively. The life form of plant species was determined by following the Raunkier's method. Therophytes comprised of 74 species (48%), Chamaephyte 40 species (26%), Hemicryptophyte 18 species (12%), Phanerophyte 19 species (12%) and Cryptophyte 3 species (2%) of the flroa of the area. It will be helpful and serve for the conservation and sustainable utilization of plant resources of the study area.

Research paper thumbnail of MO-D-134-10: Using HVL and KVp to Portray An X-Ray Source for Dose Calculations in CT

Medical Physics, 2013

ABSTRACT

Research paper thumbnail of A measurement-based X-ray source model characterization for CT dosimetry computations

Journal of applied clinical medical physics, 2015

The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and meas... more The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and measured half-value layer (HVL) can be used to generate energy spectra and fluence profiles for characterizing a computed tomography (CT) X-ray source, and to validate the source model and an in-house kV X-ray dose computation algorithm (kVDoseCalc) for computing machine- and patient-specific CT dose. Spatial variation of the X-ray source spectra of a Philips Brilliance and a GE Optima Big Bore CT scanner were found by measuring the HVL along the direction of the internal bow-tie filter axes. Third-party software, Spektr, and the nominal kVp settings were used to generate the energy spectra. Beam fluence was calculated by dividing the integral product of the spectra and the in-air NIST mass-energy attenuation coefficients by in-air dose measurements along the filter axis. The authors found the optimal number of photons to seed in kVDoseCalc to achieve dose convergence. The Philips Brilliance...

Research paper thumbnail of An Experimental X-Ray Source Characterization Method for Computed Tomography (CT) Dosimetry Simulations

Research paper thumbnail of A measurement-based X-ray source model characterization for CT dosimetry computations

Journal of applied clinical medical physics / American College of Medical Physics, Jan 8, 2015

The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and meas... more The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and measured half-value layer (HVL) can be used to generate energy spectra and fluence profiles for characterizing a computed tomography (CT) X-ray source, and to validate the source model and an in-house kV X-ray dose computation algorithm (kVDoseCalc) for computing machine- and patient-specific CT dose. Spatial variation of the X-ray source spectra of a Philips Brilliance and a GE Optima Big Bore CT scanner were found by measuring the HVL along the direction of the internal bow-tie filter axes. Third-party software, Spektr, and the nominal kVp settings were used to generate the energy spectra. Beam fluence was calculated by dividing the integral product of the spectra and the in-air NIST mass-energy attenuation coefficients by in-air dose measurements along the filter axis. The authors found the optimal number of photons to seed in kVDoseCalc to achieve dose convergence. The Philips Brilliance...

Research paper thumbnail of TU-F-CAMPUS-I-02: Validation of a CT X-Ray Source Characterization Technique for Dose Computation Using An Anthropomorphic Thorax Phantom

Medical Physics, 2015

ABSTRACT

Research paper thumbnail of MO-D-134-10: Using HVL and KVp to Portray An X-Ray Source for Dose Calculations in CT

Medical Physics, 2013

ABSTRACT

Research paper thumbnail of Sci—Thur AM: YIS - 09: Validation of a General Empirically-Based Beam Model for kV X-ray Sources

Medical Physics, 2014

ABSTRACT

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