Purpose: Adaptive filtration facilitates spectral breast CT by decreasing count rate and dynamic range requirements of photon counting detectors. This project investigated the effect of adaptive filtration on beam hardening, CT numbers, noise, and dose in dedicated breast CT. Methods: Adaptive filters were simulated to provide a flat fluence at the detector surface when used with a 14 cm breast phantom at 120 kVp. Beam hardening with each filter type was measured against increasing x-ray beam half-fan angle.. Breast CT images were simulated with and without an adaptive filter in the beam at multiple tube voltages. CT number, noise, and contrast to noise ratio (CNR) were measured for contrast elements inside the phantom. Finally, dose measurements were performed with and without an adaptive filter to determine its effect on breast dose. Results: Acrylic filters, while larger in size, provided a more uniform spectral distribution across the detector field of view compared to other filters tested. Without the adaptive filter in the beam, CT numbers, noise and CNR of the contrast elements were non-uniform across the CT images, and became uniform when the adaptive filter was used. When combining an adaptive filter and scaled x-ray exposure, the CNR increased and became comparable to or higher than the CNR without using an adaptive filter. Measurements showed breast dose distributions were more spatially uniform with an adaptive filter than without. Furthermore, the dose distribution across the phantom with the adaptive filter was more uniform at lower tube voltages than at higher tube voltages. Conclusion: We concluded the filter material should be similar to breast tissue with respect to the attenuation coefficients and density. Acrylic adaptive filters provided the flattest intensity with minimal beam hardening for the 14 cm breast phantom. Finally, breast dose uniformity with filter was comparable or better than without filter.

Purpose: To investigate the feasibility of volumetric modulated arc therapy (VMAT) for post-mastectomy radiotherapy (PMRT) and to compare dual-arc VMAT treatment plans to helical tomotherapy (HT) plans on the basis of dosimetric quality, radiobiological calculations and delivery efficiency. Methods: Dual-arc VMAT and HT treatment plans were created for fifteen patients previously treated at our clinic. Planning target volumes (PTV) included the chest wall and regional lymph nodes. The following metrics were used to compare treatment plans for each patient: dose homogeneity index (DHI) and conformity index (CI); coverage of the PTV; dose to organs at risk (OAR); tumor control probability (TCP), normal tissue complication probability (NTCP) and secondary cancer complication probability (SCCP); and treatment delivery time. Differences between treatment plans were tested for significance using the paired Students t-test. Results: Both modalities produced clinically acceptable PMRT plans. VMAT plans showed better CI (p < 0.01) and better OAR sparing at low doses than HT plans. For example, VMAT plans showed a 26% (p < 0.01) and 9% (p < 0.01) decrease in V5Gy in the lungs and heart respectively. On the other hand, HT plans showed better DHI (p < 0.01) and PTV coverage (p < 0.01). HT plans also showed better sparing at higher doses for some OARs, including 8% (p < 0.01) and 9% (p < 0.01) lower maximum doses to the lungs and heart, respectively. Both modalities achieved nearly 100% tumor control and approximately 1% NTCP in the lungs and heart, with VMAT showing lower SCCP (p < 0.01). VMAT plans also required 66.2% less time to deliver. Conclusion: Both VMAT and HT provide acceptable treatment plans for PMRT. Our study showed that VMAT in addition to being significantly faster achieved better CI and low-dose OAR sparing while HT achieved better DHI.

In this study, a proton pencil beam dose calculation algorithm was developed for a parallel, monoenergetic beam incident on a homogeneous water phantom. Fermi-Eyges theory (Eyges 1948) was used to transport pencil beams, and the characteristic width of elastic scatter events was modeled using the differential Moliere scattering power (Gottschalk 2010). The incorporation of this scattering power formalism allowed our model to account for multiple Coulomb scattering, single scattering, plural scattering, and rigorously accounted for material effects on scatter. Nonelastic nuclear interactions were incorporated into an additional pencil beam model. The attenuation of primary fluence due to nuclear events was accounted for using a weighted sum of primary and nuclear pencil beam components (Pedroni et al. 2005, Soukup et al. 2005). Free parameters of the nuclear pencil beam model were determined by a non-linear least squares fit to narrow field Monte Carlo data. Our dose calculation model was commissioned using central-axis depth dose data extracted from Monte Carlo simulations. Analytical corrections were incorporated to ensure that all input central-axis data satisfied side scatter equilibrium. <p> The dose calculation model was evaluated against Monte Carlo simulations of dose in a simplified beamline. Proton beam energies of 50, 100, 150, 200, and 250 MeV and field sizes of 4x4 cm² and 10x10 cm² were evaluated in three geometries: (1) flat phantom; (2) step phantoms (step heights of 1 and 4 cm); and (3) oblique phantom (rotation angle of 45°). All geometries evaluated with Monte Carlo dose calculations yielded 100% of points passing distance-to-agreement (DTA) ≤ 1 mm or Percent Dose Difference ≤ 3%. At least 99% of points passed with a DTA ≤ 1 mm or Percent Dose Difference ≤ 2%. The pencil beam dose calculation model provided excellent results when compared with Monte Carlo data.

In this thesis we describe data quality considerations for the Side Muon Rang Detector (SMRD), one of the six sub-detectors of the ND280 near detector of the Tokai to Kamiokande (T2K) long baseline neutrino oscillation experiment. Herein we show that the data quality of the SMRD has taken good data 99.9584% of the time it has been recording data. Also, 99.676% of SMRD data channels are shown to be operating optimally. In addition we discuss the stability of the SMRD. We find that based on a subset of data unbiased cosmic triggers have light yield of 112.8 +/- 0.3 p.e. vs. 100.7 +/- 0.5 p.e. for vertical and horizontal counters respectively. For a more stringent data set cosmic light yield for tracks with a nearly vertical path is determined to be 79:6 +/- 0.5 p.e. Detector stability is found to be related to the applied cosmic trigger mask, and this is evidenced in the increased stability of Run II over that of Run I. Also included is a basic introduction to neutrino physics and an overview of the T2K experiment.

This thesis presents a summary of the foundation and background of the field of quantum optics, and an analysis of some recent discoveries in various fields of which I have aided in furthering investigative research and advancement through publications. Such topics include numerical optimization of generalized quantum states used in phase sensitive quantum metrology, an analysis of object detection through the use of quantum interferometry in the presence of lossy conditions, and the use of the latter technique to propose an invisible quantum tripwire. First is a collaborative effort to numerically optimize quantum optical states for quantum metrological applications. We optimize two-mode, entangled, number states of light in the presence of loss in order to maximize the Fisher information, which is equivalent to minimizing the phase uncertainty. We find that in the limit of zero loss the optimal state is the so-called N00N state, for small loss, the optimal state gradually deviates from the N00N state, and in the limit of large loss the optimal state converges to a generalized two-mode coherent state, with a finite total number of photons. The results provide a general protocol for optimizing the performance of a quantum optical interferometer in the presence of photon loss. The next topic is statistical hypothesis testing of interaction free measurement and a quantitative limit on the obtainable error. Previous analyses have been based solely on detection probabilities known only in the infinite photon limit. Our analysis assumes a finite number of photons, and an investigation of reliability in the presence of photon loss and phase fluctuations. We use symmetric hypothesis testing and the Chernoff bound to provide error estimation after N independent, single photon trials. Finally, we present a quantum optical interrogation technique capable of detecting an intrusion with very low probability of the quantum tripwire being revealed to the intruder. The tripwire exploits a curious nonlinear behavior of the quantum Zeno effect we discovered, which occurs in a lossy system. We also employ statistical hypothesis testing, allowing us to calculate a confidence level of interaction-free measurement after a given number of trials.

In this dissertation I will probe the innate uncertainty of quantum mechanics. After deriving the necessary tools I will tackle Popper's experiment, a long misunderstood thought experiment with recent experimental results. I will then discuss how uncertainty changes when making measurements from different relativistic reference frames and resolve some on the tension between quantum mechanics and relativity. Finally I utilize the practical aspect of quantum uncertainty and describe a practical quantum key distribution scheme.

Purpose: To design a dual foil scattering system within Elekta Infinity radiotherapy accelerator constraints that results in clinical electron beams that meet flatness criteria of ±3% (±4%) along its principal axes (diagonal axes) for the 25x25cm2 applicator and most probable surface energies of 7-20 MeV (1 MeV increments). Methods: An analytical electron dual scattering foil system simulator was commissioned and verified using Monte Carlo (MC) simulations. Verification required comparing analytical simulator with MC-calculated electron fluence profiles for identical geometries: (1) only primary foil and (2) both primary and secondary foils in the beam. Also, simulator-calculated bremsstrahlung dose was validated by comparison to measured data. Measured dose profiles, with and without 25x25cm2 applicator, and simulator profiles were used to estimate objective profiles. Objective profiles (ideal profiles), which if achieved should produce uniform beams, were determined for current Elekta beam energies. Objective profiles were then interpolated for beam energies of 7-20 MeV in 1-MeV increments. Then, the simulator was used to design a new dual scattering foil system (5 primary and 3 secondary foils) such that the simulators design profiles closely matched the objective profiles. Design profiles were compared with MC-calculated dose profiles, after which the initial objective profiles were modified, and a second design optimization was performed. MC dose calculations were used to evaluate the modified dual scattering foil design. Results: For all design energies (7-20 MeV), the modified dual scattering foil design produced MC dose profiles that were within the flatness criteria of ±3% along the principal axes, except for 8 MeV (3.2% maximum deviation). Along the diagonal axes, the modified designs produced MC dose profiles within the flatness criteria of ±4% except at 7, 8, and 17 MeV (maximum deviation of 5.1% at 8 MeV). Conclusions: The dual scattering foil system simulator and present methodology should be capable of designing electron dual scattering foil systems provided a validated MC model of the accelerator produces accurate dose calculations (1% accuracy in beams umbra). Results of this study did not prove the hypothesis, believed due to the need for a greater number of iterations and more optimal primary foil thickness selections.

Radioactive waste is an inevitable outcome of using radioactive elements in research, education, medicine, energy, and weapons production. Low-level waste (LLW) makes up 85% of the radioactive waste produced in the United States. In 2010, over 2 million ft3 of LLW were shipped to disposal sites. Despite efforts from several states and government agencies, the options for disposing of LLW are very limited. It is the intention of this project to design a GIS based method to determine suitability of potential disposal sites based on the Code of Federal Regulations (CFR) requirements and criteria as well as supporting literature and reports. The goal of this project is to apply this method to Louisiana as the initial screening process to locate regions suitable for further evaluation as prospective disposal sites. Criteria were derived from 10 CFR part 61.50s 10 minimum requirements, the Nuclear Regulatory Commissions Regulatory Guide 0902, and a study of experiences at existing sites. A suitability formula was developed allowing for weighting factors and normalization of all criteria to a 100% scale. Data were collected and compiled into Geographic Information Systems (GIS) data sets and analyzed on a cell grid of approximately 14,000 cells (70,000 square miles) using the suitability formula and the state of Louisiana as a region of interest. Requirements were analyzed for each cell using multiple sub-criteria and surrogates for unavailable datasets. Additional criteria were added when appropriate. The method designed in this project was sufficient for initial screening tests in determining the most suitable areas for prospective disposal sites. The top 10%, 5%, and 1% include respectively 404, 88, and 4 cells suitable for further analysis. With these areas identified, the next step in siting a low-level radioactive waste storage facility would be on-site analysis using additional requirements as specified by regulatory guidelines. GIS provides an efficient and cost effective means of analyzing areas for siting LLW storage facilities and has great potential for use in other states where sufficient GIS data exist.

Purpose/Objectives: A drawbackof tandem and ovoid (T&O) ICBT is exposure of the posterior bladder and anterior rectal walls to relatively high isodoses. To mitigate this effect, intra-ovoid shielding may be used to reducedose to these OARs. However, metal artifactspresent in images acquired via kVCT make anatomy segmentation and catheter localization difficult for the purpose of 3D treatment planning. We present a method that combines MVCT-based imaging and applicator modeling to increase the quality of 3D treatment plans for shielded T&O ICBT. Materials/Methods: Using Oncentras TPS, 9 participants from multiple institutions performed organ segmentation and catheter reconstruction for KVCT and MVCT data sets acquired of a water phantom containing bladder and rectum surrogatesand various HDR T&O applicators: Nucletrons CT/MR compatible(CTMR),Nucletrons shielded Fletcher Williamson (FW) and (3) Varians shielded Fletcher-Suit-Delclos style(FSD).The dimensions of OAR structures were determined using in-air kVCT and physical measurements. By comparing the 3D volumes andcentroid-to-perimeter (C2P) measurements of individual OAR contours, segmentation accuracy was assessed in regions exhibiting artifact under kVCT (1cm superior and inferior to shielding). Comparing the TPS-defined coordinate of the most distal dwell position to that of the true position (determined using radiographs of a fiducial affixed to the applicators), assessed catheter reconstruction accuracy. For Nucletron devices, this metricwas also quantified using an applicator-model for localization. Results:The percentage of points for C2P measurements that differ (greater than 2mm) from the true contour extentsdecreased underMVCT for the shielded T&Os (78.4 vs. 71.3%), while the converse is observed for the CTMR. Similarly, the volume of the OAR surrogates follows the same trend. This is attributed to the lack of metal artifacts as well as the decrease in the contrast of low Z materials observed when utilizing MVCT. Catheter reconstruction accuracy improved by 26% under MVCT for shielded T&Os, was invariant for the CTMR and within 2.29mm of the true position using applicator modeling. Conclusions:The quality of MVCT 3D ICBT treatment plans of shielded T&O is comparable to MVCT CTMR treatment plans. Further improvements were observed when using an applicator model for catheter reconstruction.

Purpose: The purpose of this work was to create a Monte Carlo BEAMnrc/EGSnrc model of the electron beam delivery system of an Elekta Infinity linear accelerator that could simulate electron percent depth doses and off-axis profiles to within a specified tolerance criteria, ±2% relative quantities (Dmax) or 1 mm distance to agreement (DTA), when compared to a subset of the measured commissioning data for the accelerators existing set of scattering foils and applicators. Methods: The model was constructed with the BEAMnrc user code from vendor provided schematics and correspondence with manufacturer engineers under a nondisclosure agreement. The spatial distribution of the initial electron source was derived by matching the large field (open-insert 25x25 cm2 applicator) cross beam profiles calculated by the model with the measured data. The measured data was re-sampled and symmetrized about the central axis (CAX) and the simulation data was smoothed before the two data sets were normalized to reference values along the CAX. The two data sets were compared to test to the hypothesis. Results: The model was able to meet the tolerance criteria (2% of Dmax or 1 mm DTA) for all large-field %DD curves. The model was unable to meet the criteria for any large field, shallow depth cross-beam profiles. The low energy (7-, 9-MeV) and high energy (16-, 20-MeV) models over-predict off-axis dose. The medium energy (10-, 11-, 13-MeV) beam model under-predict off-axis dose. These off-axis dose discrepancies were not pronounced at smaller field-sizes (6x6 and 14x14 cm2) for the subset of the clinical beam energies (7-, 13-, 20-MeV) that were compared. Conclusions: The Monte Carlo model of the Elekta Infinity electron beam delivery system could not simulate the considered subset of measured beam data to within the tolerance criteria of the study. The model could accurately reproduce the smaller field-sizes that were compared but could not reproduce the measured large field data. The large-field off-axis dose discrepancies observed with the medium beam energies (10-, 11-, 13-MeV) could be resolved by introducing a small initial angular spread (∼2°) to the incident electron source of the model.