Clinical, physiological and anatomical determinants for radiofrequency XXXX .

@entity1 @entity221 @entity5 @entity22226
Temperature/time curves and corresponding CT scans of > 200 regional heat treatments with the @entity221 system BSD-2000 in 43 @entity1 have been analysed. In vivo variables and treatment parameters such as local specific absorption rate @entity22226 , local relative @entity22226 parallel @entity22226 parallel, total power P, local cooling coefficients wb, and local steady-state temperature elevations delta Tss (above systemic temperature) have been determined. For determination of wb the well-known and accepted steady-state approach has been used, which was slightly modified for the purposes of this study. Specifically, comparison of cooling coefficients at the beginning and end of heat treatments were performed in @entity5 and normal tissues. Other variables are anatomical descriptors from CT scans, score of side effects plim, and various clinical factors. A variance analysis of the dependent variables, specifically delta Tss and parallel @entity22226 parallel, is performed with respect to factors which were estimated as predictive. The intratumoral steady-state temperature elevations are determined by the perfusion-related cooling coefficients and local @entity22226 to almost the same extent. Increase of cooling coefficients in @entity5 during the heat treatment characterizing the thermoregulatory potential have a slight but less important influence with respect to the achieved temperature elevations. @entity22226 is influenced by several anatomical factors which determine the relative @entity22226 distribution and clinical factors which limit the total power P. However, options for controlling present RHT systems in order to optimize the relative @entity22226 distribution or to avoid hot spot phenomena appear limited. Three-dimensional modelling calculations show that the spatial arrangement of electrical interfaces emerging from bone and fat structures limits @entity22226 control in available RHT technology and is mainly responsible for local power-dependent discomfort (Wust et al. 1994b). Some conclusions are drawn, about how technological development of @entity221 technology can contribute towards overcoming this problem.
