title: Non-invasive Imaging in Gene Therapy.
abstract: Several methods are available for non-invasive imaging of gene delivery and transgene expression, including magnetic resonance imaging (MRI), single photon emission tomography (SPECT)/positron emission tomography (PET), and fluorescence and bioluminescence imaging. However, these imaging modalities differ greatly in terms of their sensitivity, cost, and ability to measure the signal. Whereas MRI can produce a resolution of approximately 50 mum, optical imaging achieves only 3-5 mm but outperforms MRI in terms of the cost of the imaging device. Similarly, SPECT and PET give a resolution of only 1-2 mm but provide for relatively easy quantitation of the signal and need only nanograms of probe, compared with the microgram or milligram levels required for MRI and optical imaging. To develop safer and more efficient gene delivery vectors, it is essential to perform rigorous in vivo experiments, to image particle biodistribution and transduction patterns, and to quantify the transgene expression profile. Differences between modalities have a significant effect on the resultant imaging resolution for gene therapy. This review describes the methodologies in use and highlights recent key approaches using the latest imaging modalities in gene therapy. Future trends in gene therapy imaging are also discussed.
authors.affiliation: Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland.
authors.forename: Jani Kristian
authors.initials: JK
authors.lastname: Räty
authors.forename: Timo
authors.initials: T
authors.lastname: Liimatainen
authors.forename: Minna
authors.initials: M
authors.lastname: Unelma Kaikkonen
authors.forename: Olli
authors.initials: O
authors.lastname: Gröhn
authors.forename: Kari Juhani
authors.initials: KJ
authors.lastname: Airenne
authors.forename: Kari
authors.initials: K
authors.lastname: Jumani Airenne
authors.forename: Seppo
authors.initials: S
authors.lastname: Ylä-Herttuala
mesh_terms: D000818:Animals; D003952:Diagnostic Imaging / Q000191:economics / Q000379:methods*; D015316:Genetic Therapy / Q000379:methods*; D006801:Humans; D008163:Luminescent Measurements; D008279:Magnetic Resonance Imaging; D049268:Positron-Emission Tomography; D015203:Reproducibility of Results; D015899:Tomography, Emission-Computed, Single-Photon