Christopher M Collins1, Michael B Smith. 1. Center for NMR Research, Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA. cmcollins@psu.edu
Abstract
PURPOSE: To examine how fine a model resolution is necessary for calculation of specific energy absorption rate (SAR) for the human head in regions as small as 1 g. MATERIALS AND METHODS: Here we perform a simple study comparing the maximum SAR averaged over any 1 cm(3) and SAR averaged over the entire head for several models of the same human head within the same radiofrequency coil, but with spatial resolutions varying from 8-100 Yee cells per cm(3). RESULTS: Over the range of model resolutions from 8-100 Yee cells per cm(3), there is only a 16% variation in maximum SAR in any 1 cm(3) of tissue in the head, and only a 7% variation in SAR averaged over the entire head. CONCLUSION: While it is always desirable to perform SAR calculations with the greatest possible accuracy, in calculations of the maximum SAR levels in any 1 cm(3) of tissue, spatial resolutions greater than 5 mm may not yield notably different results than those with a spatial resolution of 5 mm. Copyright 2003 Wiley-Liss, Inc.
PURPOSE: To examine how fine a model resolution is necessary for calculation of specific energy absorption rate (SAR) for the human head in regions as small as 1 g. MATERIALS AND METHODS: Here we perform a simple study comparing the maximum SAR averaged over any 1 cm(3) and SAR averaged over the entire head for several models of the same human head within the same radiofrequency coil, but with spatial resolutions varying from 8-100 Yee cells per cm(3). RESULTS: Over the range of model resolutions from 8-100 Yee cells per cm(3), there is only a 16% variation in maximum SAR in any 1 cm(3) of tissue in the head, and only a 7% variation in SAR averaged over the entire head. CONCLUSION: While it is always desirable to perform SAR calculations with the greatest possible accuracy, in calculations of the maximum SAR levels in any 1 cm(3) of tissue, spatial resolutions greater than 5 mm may not yield notably different results than those with a spatial resolution of 5 mm. Copyright 2003 Wiley-Liss, Inc.
Authors: Zhangwei Wang; James C Lin; Weihua Mao; Wanzhan Liu; Michael B Smith; Christopher M Collins Journal: J Magn Reson Imaging Date: 2007-08 Impact factor: 4.813
Authors: Nikos Makris; Leonardo Angelone; Seann Tulloch; Scott Sorg; Jonathan Kaiser; David Kennedy; Giorgio Bonmassar Journal: Med Biol Eng Comput Date: 2008-11-05 Impact factor: 2.602
Authors: Hongbae Jeong; Georgios Ntolkeras; Michel Alhilani; Seyed Reza Atefi; Lilla Zöllei; Kyoko Fujimoto; Ali Pourvaziri; Michael H Lev; P Ellen Grant; Giorgio Bonmassar Journal: PLoS One Date: 2021-01-13 Impact factor: 3.240