Assessment of the local SAR distortion by major anatomical structures in a cylindrical neck phantom
| Autor: | G. C. Van Rhoon, D. H. M. Wielheesen, Margarethus M. Paulides, J. van der Zee |
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| Přispěvatelé: | Radiation Oncology |
| Rok vydání: | 2005 |
| Předmět: |
Physics
Cancer Research Hot Temperature Physiology Phantoms Imaging Anatomical structures Finite-difference time-domain method High resolution Cylindrical phantom Anatomy Hyperthermia Induced Models Theoretical equipment and supplies Imaging phantom body regions Antenna array Head and Neck Neoplasms Physiology (medical) Intensive care Humans skin and connective tissue diseases Head and neck Biomedical engineering |
| Zdroj: | International Journal of Hyperthermia, 21(2), 125-140. Informa Healthcare |
| ISSN: | 0265-6736 |
| Popis: | The objective of this work is to gain insight in the distortions on the local SAR distribution by various major anatomical structures in the neck. High resolution 3D FDTD calculations based on a variable grid are made for a semi-3D generic phantom based on average dimensions obtained from CT-derived human data and in which simplified structures representing trachea, cartilage, spine and spinal cord are inserted. In addition, phantoms with dimensions equal to maximum and minimum values within the CT-derived data are also studied. In all cases, the phantoms are exposed to a circular coherent array of eight dipoles within a water bolus and driven at 433 MHz. Comparisons of the SAR distributions due to individual structures or a combination of structures are made relative to a cylindrical phantom with muscle properties. The calculations predict a centrally located region of high SAR within all neck phantoms. This focal region, expressed as contours at either 50% or 75% of the peak SAR, changes from a circular cross-section in the case of the muscle phantom to a doughnut shaped region when the anatomical structures are present. The presence of the spine causes the greatest change in the SAR distribution, followed closely by the trachea. Global changes in the mean SAR relative to the uniform phantom are |
| Databáze: | OpenAIRE |
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