Publications by authors named "Christopher R Dillon"
Article Synopsis
- In focused ultrasound (FUS) thermal ablation, a new treatment planning method using hybrid angular spectrum and Pennes' bioheat equation has been validated through experiments on tissue-mimicking phantoms.
- Simulated temperature profiles showed a mean error of +0.33°C when compared to actual MR thermometry imaging, indicating the simulations are reliable despite some uncertainty.
- The study highlights the significance of accurately measuring patient-specific tissue properties to enhance treatment planning and outcomes for FUS surgeries.
Article Synopsis
- The study aims to create a model that links the duration and symmetry of k-space-weighted image contrast (KWIC) windows to the temporal resolution in ultrasound imaging.
- A modulation analysis of temperature measurements was conducted, leading to the comparison of simulated and experimental results using different KWIC window setups.
- Findings reveal that the effectiveness of KWIC reconstructions varies with object size, with shorter window durations improving accuracy but potentially reducing precision; symmetric windows minimize response delays but complicate reconstruction timings.
Purpose: This study validates that phase aberrations in breast magnetic resonance-guided focussed ultrasound (MRgFUS) therapies can be corrected in a clinically relevant time frame to generate more intense, smaller and more spatially accurate foci.
Materials And Methods: Hybrid angular spectrum (HAS) ultrasound calculations in an magnetic resonance imaging (MRI)-based tissue model, were used to compute phase aberration corrections for improved experimental MRgFUS heating in four heterogeneous breast-mimicking phantoms (n = 18 total locations). Magnetic resonance(MR) temperature imaging was used to evaluate the maximum temperature rise, focus volume and focus accuracy for uncorrected and phase aberration-corrected sonications.
Article Synopsis
- This study assesses whether thermal diffusivity and the Pennes perfusion parameter can be measured non-invasively using temperature data from magnetic resonance-guided focused ultrasound (MRgFUS) in both pre-clinical and clinical settings.
- Experiments involving rabbits and human clinical cases were performed, showing that including cooling data significantly reduces variability in the measured properties, leading to results that are comparable to traditional invasive measurements.
- The findings indicate that these thermal properties can be determined effectively with MRgFUS techniques, with better accuracy when cooling data is used, supporting future clinical applications.
Purpose: This simulation study evaluates the effects of phase aberration in breast MR-guided focused ultrasound (MRgFUS) ablation treatments performed with a phased-array transducer positioned laterally to the breast. A quantification of these effects in terms of thermal dose delivery and the potential benefits of phase correction is demonstrated in four heterogeneous breast numerical models.
Methods: To evaluate the effects of varying breast tissue properties on the quality of the focus, four female volunteers with confirmed benign fibroadenomas were imaged using 3T MRI.
Purpose: The use of correct tissue thermal diffusivity values is necessary for making accurate thermal modelling predictions during magnetic resonance-guided focused ultrasound (MRgFUS) treatment planning. This study evaluates the accuracy and precision of two non-invasive thermal diffusivity estimation methods, a Gaussian temperature method and a Gaussian specific absorption rate (SAR) method.
Materials And Methods: Both methods utilise MRgFUS temperature data obtained during cooling following a short (<25 s) heating pulse.