The maximum spatial peak exposure of each commercial mobile phone determined in compliance with the relevant safety and product standards is publicly available. However, this information is not sufficient for epidemiological studies aiming to correlate the use of mobile phones with specific cancers or to behavioral alterations. The objective of this study was to develop a methodology to determine tissue-specific exposure by expanding the post-processing of the measured surface or volume scans using standardized compliance testing equipment. A transformation matrix was developed to evaluate the SAR in virtual brain regions of the homogeneous SAM head compared to the SAR in four anatomical heads of the Virtual Family. The new methodology enables the reliable determination of the maximum and averaged exposure of specific tissues (e.g., brain tissues) to mobile phones when combined with over-the-air performance data, and therefore greatly strengthens epidemiological evaluations and improves information for the consumer.