Lipid-Based Pharmaceutical Nanocarriers for Imaging Applications - Nanotechnology for Biomedical Imaging and Diagnostics - page 64

0 h 4 h

figure 3.4 Three-dimensional angiography of mice injected with antitumor mAb2C5-
modified gd-pAp-containing pEgylated liposomes. dotted ovals show tumor location. Notice
good tumor visualization with 2C5-modified liposomes already after 4 h. (With kind permis-
sion from ref. [111]. © John Wiley & sons, inc.)

pEgylated liposomes labeled with positron emitter ( 18 f) have been used for pET
imaging of brain cancer (glioma) in rats [118]. 64 Cu-labeled liposomes represent
another example of pET imaging agent and have been successfully used for tumor
imaging in mice [119]. similar liposomes have also been used for pET imaging of
the human neuroendocrine carcinoma in mice [120].

3.4.3 contrast-Loaded Nanocarriers in cardiovascular system

Blood pool imaging is of special interest for the evaluation of the current state of
blood flow and for the discovery of its irregularities caused by atherosclerotic lesions,
thrombi, or tumors. Blood pool imaging (experimental so far) requires the prolonged
circulation of diagnostic nanocarriers and is usually based on the utilization of steri-
cally protected nanocarriers loaded with 111 in, 67 ga, gd, heavily iodinated organic
compounds, and gas bubbles. Blood perfusion and various cardiac parameters (ven-
tricular ejection fraction, cardiac output, and wall motion being among them) can be
evaluated in all imaging modalities [92, 121]. Therefore contrast-loaded nanocarriers
may serve as a good alternative for currently used 99m Tc-labeled red blood cells for
the same purposes, which do not allow acquisition of desirable quality images
because of the fast accumulation of the latter in the liver.
plain, nonmodified nanocarriers loaded with 99m Tc-dTpA accumulate to some
extent in infarcted areas (experimental myocardial infarction) via the impaired filtra-
tion mechanism (extravasation through ischemically damaged blood vessels) [122].
However, the degree of this accumulation is insufficient to obtain diagnostically