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Smith, A

Publications and source records attributed to Smith, A.

11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

SU-F-J-29: Dosimetric Effect of Image Registration ROI Size and Focus in Automated CBCT Registration for Spine SBRT

Purpose: Spinal stereotactic body radiotherapy (SBRT) involves highly conformal dose distributions and steep dose gradients due to the proximity of the spinal cord to the treatment volume. To achieve the planning goals while limiting the spinal cord dose, patients are setup using kV cone-beam CT (kV-CBCT) with 6 degree corrections. The kV-CBCT registration with the reference CT is dependent on a user selected region of interest (ROI). The objective of this work is to determine the dosimetric impact of ROI selection. Methods: Twenty patients were selected for this study. For each patient, the kV-CBCT was registered to the reference CT using three ROIs including: 1) the external body, 2) a large anatomic region, and 3) a small region focused in the target volume. Following each registration, the aligned CBCTs and contours were input to the treatment planning system for dose evaluation. The minimum dose, dose to 99% and 90% of the tumor volume (D99%, D90%), dose to 0.03cc and the dose to 10% of the spinal cord subvolume (V10Gy) were compared to the planned values. Results: The average deviations in the tumor minimum dose were 2.68%±1.7%, 4.6%±4.0%, 14.82%±9.9% for small, large and the external ROIs, respectively. The average deviations in tumor D99% were 1.15%±0.7%, 3.18%±1.7%, 10.0%±6.6%, respectively. The average deviations in tumor D90% were 1.00%±0.96%, 1.14%±1.05%, 3.19%±4.77% respectively. The average deviations in the maximum dose to the spinal cord were 2.80%±2.56%, 7.58%±8.28%, 13.35%±13.14%, respectively. The average deviation in V10Gy to the spinal cord were 1.69%±0.88%, 1.98%±2.79%, 2.71%±5.63%. Conclusion: When using automated registration algorithms for CBCT-Reference alignment, a small target-focused ROI results in the least dosimetric deviation from the plan. It is recommended to focus narrowly on the target volume to keep the spinal cord dose below tolerance.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

HerMES: A STATISTICAL MEASUREMENT OF THE REDSHIFT DISTRIBUTION OF HERSCHEL-SPIRE SOURCES USING THE CROSS-CORRELATION TECHNIQUE

The wide-area imaging surveys with the Herschel Space Observatory at submillimeter (sub-mm) wavelengths have now resulted in catalogs of the order of one-hundred-thousand dusty, starburst galaxies. These galaxies capture an important phase of galaxy formation and evolution, but, unfortunately, the redshift distribution of these galaxies, N(z), is still mostly uncertain due to limitations associated with counterpart identification at optical wavelengths and spectroscopic follow-up. We make a statistical estimate of N(z) using a clustering analysis of sub-mm galaxies detected at each of 250, 350 and 500 {mu}m from the Herschel Multi-tiered Extragalactic Survey centered on the Booetes field. We cross-correlate Herschel galaxies against galaxy samples at optical and near-IR wavelengths from the Sloan Digital Sky Survey, the NOAO Deep Wide Field Survey, and the Spitzer Deep Wide Field Survey. We create optical and near-IR galaxy samples based on their photometric or spectroscopic redshift distributions and test the accuracy of those redshift distributions with similar galaxy samples defined with catalogs from the Cosmological Evolution Survey (COSMOS), which has superior spectroscopic coverage. We model the clustering auto- and cross-correlations of Herschel and optical/IR galaxy samples to estimate N(z) and clustering bias factors. The S{sub 350} > 20 mJy galaxies have a bias factor varying with redshift as b(z) = 1.0{sup +1.0}{sub -0.5}(1 + z){sup 1.2{sup +{sup 0{sup .{sup 3{sub -}{sub -}{sub 0}{sub .}{sub 7}}}}}}. This bias and the redshift dependence is broadly in agreement with galaxies that occupy dark matter halos of mass in the range of 10{sup 12} to 10{sup 13} M{sub Sun }. We find that galaxy selections in all three Spectral and Photometric Imaging Receiver (SPIRE) bands share a similar average redshift, with (z) = 1.8 {+-} 0.2 for 250 {mu}m selected samples, and (z) = 1.9 {+-} 0.2 for both 350 and 500 {mu}m samples, while their distributions behave differently. For 250 {mu}m selected galaxies we find the a larger number of sources with z {<=} 1 when compared with the subsequent two SPIRE bands, with 350 and 500 {mu}m selected SPIRE samples having peaks in N(z) at progressively higher redshifts. We compare our clustering-based N(z) results to sub-mm galaxy model predictions in the literature, and with an estimate of N(z) using a stacking analysis of COSMOS 24 {mu}m detections.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

Techniques in teaching statistics : linking research production and research use.

In the spirit of closing the 'research-practice gap,' the authors extend evidence-based principles to statistics instruction in social science graduate education. The authors employ a Delphi method to survey experienced statistics instructors to identify teaching techniques to overcome the challenges inherent in teaching statistics to students enrolled in practitioner-oriented master's degree programs. Among the teaching techniques identi?ed as essential are using real-life examples, requiring data collection exercises, and emphasizing interpretation rather than results. Building on existing research, preliminary interviews, and the ?ndings from the study, the authors develop a model describing antecedents to the strength of the link between research and practice.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2011

Neutron-unbound states in {sup 25,26}F

Neutron-unbound states in {sup 25}F and {sup 26}F were populated via the reactions {sup 9}Be({sup 26}Ne,{sup 24}F + n) and {sup 9}Be({sup 26}Ne,{sup 25}F + n), respectively. A resonance close to the neutron separation energy in {sup 25}F was identified with a decay energy of 28{+-}4 keV. This resonance corresponds to an excited state in {sup 25}F at 4249{+-}116 keV assuming it decays to the ground state of {sup 24}F. Guided by shell-model calculations, a spin and parity of 1/2{sup -} can be assigned to this state. In the spectrum of {sup 26}F, which was produced in a nucleon-exchange reaction, there are indications for an excited state with a decay energy of {approx}270 keV.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

ISSUES ASSOCIATED WITH SAFE PACKAGING AND TRANSPORT OF NANOPARTICLES

Nanoparticles have long been recognized a hazardous substances by personnel working in the field. They are not, however, listed as a separate, distinct category of dangerous goods at present. As dangerous goods or hazardous substances, they require packaging and transportation practices which parallel the established practices for hazardous materials transport. Pending establishment of a distinct category for such materials by the Department of Transportation, existing consensus or industrial protocols must be followed. Action by DOT to establish appropriate packaging and transport requirements is recommended.

42 ENGINEERING↗
DOE OSTI2010

Charge Diagnostics for Laser Plasma Accelerators

The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1% per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/ps/mm{sup 2}, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within {+-}10%.

43 PARTICLE ACCELERATORS↗
DOE OSTI2010

EARLY TESTS OF DRUM TYPE PACKAGINGS - THE LEWALLEN REPORT

The need for robust packagings for radioactive materials (RAM) was recognized from the earliest days of the nuclear industry. The U.S. Department of Energy (DOE) Rocky Flats Plant developed a packaging for shipment of Pu in the early 1960's, which became the U.S. Department of Transportation (DOT) 6M specification package. The design concepts were employed in other early packagings. Extensive tests of these at Savannah River Laboratory (now Savannah River National Laboratory) were performed in 1969 and 1970. The results of these tests were reported in 'Drum and Board-Type Insulation Overpacks of Shipping Packages for Radioactive Materials', by E. E. Lewallen. The Lewallen Report was foundational to design of subsequent drum type RAM packaging. This paper summarizes this important early study of drum type packagings. The Lewallen Report demonstrated the ability packagings employing drum and insulation board overpacks and engineered containment vessels to meet the Type B package requirements. Because of the results of the Lewallen Report, package designers showed high concern for thermal protection of 'Celotex'. Subsequent packages addressed this by following strategies like those recommended by Lewallen and by internal metal shields and supplemental, encapsulated insulation disks, as in 9975. The guidance provide by the Lewallen Report was employed in design of a large number of drum size packagings over the following three decades. With the increased public concern over transportation of radioactive materials and recognition of the need for larger margins of safety, more sophisticated and complex packages have been developed and have replaced the simple packagings developed under the Lewallen Report paradigm.

42 ENGINEERING↗
DOE OSTI2010

CRUSH TESTING OF 9977 GENERAL PURPOSE FISSILE PACKAGINGS

The 9977 General Purpose Fissile Package (GPFP) was designed in response to the adoption of the crush test requirement in the US regulations for packages for radioactive materials (10 CFR 71). This presentation on crush testing of the 9977 GPFP Reviews origins of Crush Test Requirements and implementation of crush test requirements in 10 CFR 71. SANDIA testing performed to support the rule making is reviewed. The differences in practice, on the part of the US Department of Energy from those required by the NRC for commercial purposes, are explained. The design features incorporated into the 9977 GPFP to enable it to withstand the crush test and the crush tests performed on the 9977 are described. Lessons learned from crush testing of GPFP packagings are given.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2010

Charge Diagnostics for Laser Plasma Accelerators

The electron energy dependence of a scintillating screen (Lanex Fast) was studied with sub-nanosecond electron beams ranging from 106 MeV to 1522 MeV at the Lawrence Berkeley National Laboratory Advanced Light Source (ALS) synchrotron booster accelerator. The sensitivity of the Lanex Fast decreased by 1percent per 100 MeV increase of the energy. The linear response of the screen against the charge was verified with charge density and intensity up to 160 pC/mm2 and 0.4 pC/ps/mm2, respectively. For electron beams from the laser plasma accelerator, a comprehensive study of charge diagnostics has been performed using a Lanex screen, an integrating current transformer, and an activation based measurement. The charge measured by each diagnostic was found to be within +/-10 percent.

43 PARTICLE ACCELERATORS↗