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Spherical polar co-ordinate calculations of induced fields in the retina and head for applied magnetic fields at 50 Hz.
MedLine Citation:
PMID:  21725142     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
This paper sets out to explore the effects of voxel resolution, from 2 mm down to 0.1 mm for Cartesian co-ordinates and the differences between Cartesian and spherical polar co-ordinates for a standardized test-bed model of the eye. This model was taken from the work of Yoriyaz et al (2005 Radiat. Prot. Dosim. 115 316-9) who have developed a detailed geometric description of the eye including choroid, retina, sclera, lens, cornea, anterior chamber, vitreous humour and optic nerve for ophthalmic brachytherapy. The spherical co-ordinate model has radial and angular steplengths of 0.1 mm and 0.25°, respectively. The current density averaged over 1 cm(2) and the 99th percentile value of the induced electric field have been calculated in the retina and central nervous system for uniform magnetic fields. The Cartesian co-ordinate calculations proceed in a sequence of grids at 2, 1, 0.5, 0.2 and 0.1 mm resolution with the potentials from the previous calculation at a coarser grid providing the boundary conditions on the finer grid. The 0.2 mm grid provides the boundary conditions for the spherical polar calculations. Comparisons are made with the International Commission on Non-Ionizing Radiation Protection reference levels.
Authors:
Peter Dimbylow
Publication Detail:
Type:  Journal Article     Date:  2011-07-01
Journal Detail:
Title:  Physics in medicine and biology     Volume:  56     ISSN:  1361-6560     ISO Abbreviation:  Phys Med Biol     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-07-04     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  4597-611     Citation Subset:  IM    
Affiliation:
Health Protection Agency, Chilton, Didcot, Oxon OX11 0RQ, UK.
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