[Molecular imaging--diagnosis by functional imaging].

In the 20th century, technological innovation in instrumentation has enabled us to noninvasively observe the structural detail of organs and tissues in diagnostic imaging. The 21st century is the era of analyzing the whole body at the molecular level as symbolized by post-genomic studies. In addition to structural information, functional information will be applied to the non-invasive imaging of the human organ functions in the near future. Thus, the era of structural imaging will progress to the era of functional imaging. Recent progress in optical imaging has accelerated the multimodality of instruments for structural imaging such as magnetic resonance imaging(MRI)and computerized tomography( CT), and functional imaging with molecular probes. Although there are many limitations to optical modality for whole body imaging, the multi-functional nature of optics will cause a revolution in diagnostic imaging.