Nuclear medicine techniques for <i>in vivo</i> animal imaging
The object of the study was to analyze radionuclide detection techniques for in vivo animal imaging. Material and Methods. A total of 49 publications available from Scopus, Web of Science, Google Scholar eLIBRARY and Pubmed and published between 2013 and 2019 were reviewed. Results. The nuclear medicine techniques, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT) are the most suitable imaging modalities for in vivo animal imaging. Besides traditional radiopharmaceuticals, such as [<sup>18</sup>F]-FDG and [<sup>99</sup>mTc]-MDP, the new radiolabeled tracers, such as [<sup>99m</sup>Tc]-3PRGD2, [<sup>99m</sup>Tc]-HisoDGR targeted to integrin, [<sup>18</sup>F]- tetrafluoroborate, labeled antibodies and others have been used for the noninvasive detection of tumors and for monitoring their response to treatment in mice and rats. <sup>111</sup> In and <sup>89</sup>Zr -labeled monoclonal antibodies are used to evaluate the expression level of many receptors such as EGFR, HER-2 and others in different tumors. PET imaging has demonstrated a good efficacy in tumor hypoxia imaging with [<sup>64</sup>Cu]-ATSM, [<sup>18</sup>F]-FMISO. PET and SPECT can also be used for early evaluation of anticancer therapy response. Nuclear imaging techniques may assist in the vivo assessment of DNA damage (double-and single-strand brakes) as well as apoptosis intensity in tumor and normal tissues. [<sup>99m</sup>Tc]- duramycin is the most commonly used tracer for imaging of apoptosis. Changes in tumor cell proliferation in response to anticancer therapy can be assessed by PET imaging with [<sup>18</sup>F]-FLT. Conclusion. Nuclear medicine offers a unique means to study cancer biology in vivo and to optimize cancer therapy.