Browsing by Author "Martinez Fernandez, Pedro Enrique"
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- ItemOpen AccessApplication of a finite-difference scheme for the time-domain computation of 1D anelastic wavefields to fractured media.(2014-07-07) Martinez Fernandez, Pedro Enrique; Krebes, Edward StephenIn this work, I develop a 1D finite-difference formulation that is capable of simulating non-welded contact boundary conditions in anelastic media. I include, in the linear-slip boundary conditions for non-welded contact, the memory variables that are obtained as a result of considering a generalized Maxwell rheology. Then I proceed to obtain a heterogeneous formulation which is a result of the introduction of a fictitious points scheme for the boundary conditions. In other words I obtain a generalized homogeneous formulation. I solve the resulting system of equations and substitute the amplitudes obtained into the equation of motion. I analyze the numerical results obtained and compare these with an analytical solution and two other anelastic formulations for the welded contact case. I examine different scenarios such as anelastic-anelastic and elastic-anelastic wave propagation in welded and non-welded contact by looking at the transmitted and reflected pulse in welded as well as non-welded contact.
- ItemOpen AccessCatheter Placement Optimization using Hybrid Inverse Planning and Optimization for Focal High Dose Rate Brachytherapy in Patients with Pubic Arch Interference(2021-09-20) Martinez Fernandez, Pedro Enrique; Thind, Kundan; Meyer, Tyler; Martell, Kevin; McGeachy, Philip; Morrison, HaliPositive clinical outcomes are well correlated with an increase in dose delivered to the Dominant Intraprostatic Lesion (DIL) in prostate cancer radiotherapy treatments. The DIL represents a concentration of high-grade cancerous tissue and is the most common site of prostate cancer recurrence. One of the most promising tools to achieve dose escalation is via focal High Dose Rate Brachytherapy (FHDR-BT). Traditionally, HDR-BT is used along with External Beam Radiotherapy (EBRT) to deliver a whole prostate boost for unfavourable intermediate and high-risk patients or as a monotherapy alternative for low, very low, and favourable intermediate patients. However, with the introduction of new imaging techniques such as multiparametric Magnetic Resonance Imaging (mp-MRI), there is the potential to further escalate the dose to the DIL. Currently, there is limited information on the impact of Pubic Arch Interference (PAI) in dose escalation therapies such as FHDR-BT. In this work, we use Hybrid Inverse Planning and Optimization (HIPO) to simulate the planning of clinically representative scenarios built using a cohort of patients with Pubic Arch Interference (PAI), previously treated at our institution. We simulate varying levels of PAI by changing the location of the DIL. In addition, we also test the capability of HIPO to create clinically satisfactory plans under challenging anatomical conditions of PAI and prostate size. The results presented in this investigation show that HIPO can be used as an effective tool for dose escalation to the DIL in patients with PAI.