The evaluation of non-invasive microwave thermometry using a differential microwave imaging appro... more The evaluation of non-invasive microwave thermometry using a differential microwave imaging approach is investigated in an experimental setup. The setup consists of a monopole microwave tomographic system, a muscle phantom, and a circulation/heating system. The saline solution is used as the heated medium inside the muscle phantom. Based on Born Approximation and regularization by TSVD we reconstructed the distribution of both dielectric parameters, relative permittivity and electrical conductivity inside the investigation area. A promising agreement between measured and reconstructed electrical conductivity was achieved and some specifics for future improvement of microwave thermometry were identified.
European Conference on Antennas and Propagation, 2014
A novel antenna applicator for microwave hyperthermia allowing treatment of deep brain tumors is ... more A novel antenna applicator for microwave hyperthermia allowing treatment of deep brain tumors is proposed. The applicator consists of up to 16 antennas placed around the head in a helmet-like set-up and operates at a frequency range of 430-1000~MHz. The self-grounded bow-tie antennas are housed in a molded plastic enclosure with the shape of a truncated cone. The inner space of the enclosure is filled with distilled water. The antennas are attached to a perimetric water bolus with a thickness of 2 cm and aligned with the head shape. The focusing ability of the applicator was investigated on a homogeneous SAM model and on a model of a 13-year old patient containing a spherical tumor of 2 cm radius. Two different tumor positions were investigated: the right frontal lobe and the central brain. The obtained SAR distributions are favorable, although a relatively high level of energy is also absorbed on the surface of the body. This heating is however not expected to cause problems as it can be cooled by blood perfusion and water bolus. Our results show that focused microwave heating in the brain is feasible and warrants further verification on phantoms.
Phased arrays are the common type of applicators for deep hyperthermia systems to heat tumors sel... more Phased arrays are the common type of applicators for deep hyperthermia systems to heat tumors selectively while keeping healthy tissues at normal temperatures. Annular array applicators with dipoles and water bolus have been improved in several studies to deposit energy efficiently in head and neck tumors. In this study we investigate the performance of a modified Bow-Tie antenna versus half-wave dipole as single elements in annular phased array applicators to heat tumors in head and neck region. Hyperthermia quality indicators have been calculated for each case to quantify the quality of treatment outcome in two different tumor positions in a head-and-neck phantom. The obtained results indicates that dipoles are appropriate phased array elements to heat superficial tumors, while modified Bow-Ties are more suitable in heating big deep-seated tumors.
The evaluation of non-invasive microwave thermometry using a differential microwave imaging appro... more The evaluation of non-invasive microwave thermometry using a differential microwave imaging approach is investigated in an experimental setup. The setup consists of a monopole microwave tomographic system, a muscle phantom, and a circulation/heating system. The saline solution is used as the heated medium inside the muscle phantom. Based on Born Approximation and regularization by TSVD we reconstructed the distribution of both dielectric parameters, relative permittivity and electrical conductivity inside the investigation area. A promising agreement between measured and reconstructed electrical conductivity was achieved and some specifics for future improvement of microwave thermometry were identified.
European Conference on Antennas and Propagation, 2014
A novel antenna applicator for microwave hyperthermia allowing treatment of deep brain tumors is ... more A novel antenna applicator for microwave hyperthermia allowing treatment of deep brain tumors is proposed. The applicator consists of up to 16 antennas placed around the head in a helmet-like set-up and operates at a frequency range of 430-1000~MHz. The self-grounded bow-tie antennas are housed in a molded plastic enclosure with the shape of a truncated cone. The inner space of the enclosure is filled with distilled water. The antennas are attached to a perimetric water bolus with a thickness of 2 cm and aligned with the head shape. The focusing ability of the applicator was investigated on a homogeneous SAM model and on a model of a 13-year old patient containing a spherical tumor of 2 cm radius. Two different tumor positions were investigated: the right frontal lobe and the central brain. The obtained SAR distributions are favorable, although a relatively high level of energy is also absorbed on the surface of the body. This heating is however not expected to cause problems as it can be cooled by blood perfusion and water bolus. Our results show that focused microwave heating in the brain is feasible and warrants further verification on phantoms.
Phased arrays are the common type of applicators for deep hyperthermia systems to heat tumors sel... more Phased arrays are the common type of applicators for deep hyperthermia systems to heat tumors selectively while keeping healthy tissues at normal temperatures. Annular array applicators with dipoles and water bolus have been improved in several studies to deposit energy efficiently in head and neck tumors. In this study we investigate the performance of a modified Bow-Tie antenna versus half-wave dipole as single elements in annular phased array applicators to heat tumors in head and neck region. Hyperthermia quality indicators have been calculated for each case to quantify the quality of treatment outcome in two different tumor positions in a head-and-neck phantom. The obtained results indicates that dipoles are appropriate phased array elements to heat superficial tumors, while modified Bow-Ties are more suitable in heating big deep-seated tumors.
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