Diarmuid O'Connell

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The article aims to determine if a prospective acquisition algorithm can be used to find the ideal set of free-breathing phases for fast-helical model-based 4D-CT. A retrospective five-patient dataset that consisted of 25 repeated free breathing CT scans per patient was used. The sum of the square root amplitude difference between all the breathing phases(More)
This paper introduces a new actuation scheme for implementing Pulsed Digital Oscillators (PDOs) for electrostatic MEMS resonators. In this scheme, the capacitance of the device is biased with a voltage and it is periodically sampled. Short pulses of zero voltage are applied depending on the decisions taken by the oscillator loop. The paper discusses in(More)
PURPOSE Magnetic resonance image (MRI) guided radiotherapy enables gating directly on target position for soft-tissue targets in the lung and abdomen. We present a dosimetric evaluation of a commercially-available FDA-approved MRI-guided radiotherapy system's gating performance using a MRI-compatible respiratory motion phantom and radiochromic film. (More)
PURPOSE To evaluate the effect of inter- and intra-fractional tumor motion on the error in four-dimensional computed tomography (4DCT) maximal intensity projection (MIP)-based lung tumor internal target volumes (ITV), using deformable image registration of real-time 2D-sagital cine-mode MRI acquired during lung SBRT treatments. METHODS Five lung tumor(More)
PURPOSE 5DCT employs 25 fast helical scans and breathing surrogate monitoring to sample the respiratory cycle. Deformable image registration is used to fit a correspondence model between tissue motion and breathing amplitude and rate. The number of scans was chosen to ensure a high probability that tissues were imaged at sufficiently distinct breathing(More)
PURPOSE A published 5DCT breathing motion model enables image reconstruction at any user-selected breathing phase, defined by the model as a specific amplitude (v) and rate (f). Generation of reconstructed phase-specific CT scans will be required for time-independent radiation dose distribution simulations. This work answers the question: how many amplitude(More)
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