Nanomaterials for Medical Imaging …
357
Fig. 13 Combination of up-conversion particles loaded into TaOx NPs. The unique combination
of particles depicts localization in the lymph node exposed with two different concentrations (a).
A gradual decrease in the contrast over time up to 144 h along with 3D reconstructed images (b).
Adapted from reference [122]
combination of nanoformulation showed excellent in vivo imaging in CT/MRI/Upconversion particle from TaO/Gd
3+ /NaYF 4 : Yb
3+ /Er
3+ /Tm
3+, respectively. Distribution of nanoprobes was imaged using CT by tail vein injection at a concentration of
64 mg mL
−1 were able to localize and map lymph nodes at different time points.
Within 10 min, CT imaging showed increased accumulation in the liver and spleen
and enhanced contrast after 3 h of injection (see Fig. 13).
6.7 Yttrium Based CT Agents
The above elements, such as Au, Ta, Bi, were used as CT contrast agents either
in its metallic or oxide or sulphide states [124]. In line with this, the ionic form
of Ytterbium (Yb) is another promising material like Iodine but has a high X-ray
attenuation at 62 keV. Most importantly, a chelated form of Ytterbium is less toxicity
in rodents [125] and the highest availability in earth crust [126], which enables them
to produce CT contrast agents in large amounts. Also, Yb has a significant absorption
in the NIR range that can be used for the synthesis of multimodal imaging probes
and also for up-conversion nanomaterials [127]. The first experiment was performed
in 1986 by Unger et al. by chelating Yb using DTPA as a potential intravascular CT
contrast [128]. Compared to Iodine, Yb and Gd showed much higher radiopacity
when injected in different dogs showed high SNR in imaging pulmonary artery
and its branches when excited at 125 kVp [129, 130]. Though there are several
remarkable studies shown in the literature that Yb based chelating agents have some
disadvantages when injected in vivo. 1. The large amount of Yb has to be injected
to obtain valuable diagnostic information. 2. They have minimal time in the blood
357
Fig. 13 Combination of up-conversion particles loaded into TaOx NPs. The unique combination
of particles depicts localization in the lymph node exposed with two different concentrations (a).
A gradual decrease in the contrast over time up to 144 h along with 3D reconstructed images (b).
Adapted from reference [122]
combination of nanoformulation showed excellent in vivo imaging in CT/MRI/Upconversion particle from TaO/Gd
3+ /NaYF 4 : Yb
3+ /Er
3+ /Tm
3+, respectively. Distribution of nanoprobes was imaged using CT by tail vein injection at a concentration of
64 mg mL
−1 were able to localize and map lymph nodes at different time points.
Within 10 min, CT imaging showed increased accumulation in the liver and spleen
and enhanced contrast after 3 h of injection (see Fig. 13).
6.7 Yttrium Based CT Agents
The above elements, such as Au, Ta, Bi, were used as CT contrast agents either
in its metallic or oxide or sulphide states [124]. In line with this, the ionic form
of Ytterbium (Yb) is another promising material like Iodine but has a high X-ray
attenuation at 62 keV. Most importantly, a chelated form of Ytterbium is less toxicity
in rodents [125] and the highest availability in earth crust [126], which enables them
to produce CT contrast agents in large amounts. Also, Yb has a significant absorption
in the NIR range that can be used for the synthesis of multimodal imaging probes
and also for up-conversion nanomaterials [127]. The first experiment was performed
in 1986 by Unger et al. by chelating Yb using DTPA as a potential intravascular CT
contrast [128]. Compared to Iodine, Yb and Gd showed much higher radiopacity
when injected in different dogs showed high SNR in imaging pulmonary artery
and its branches when excited at 125 kVp [129, 130]. Though there are several
remarkable studies shown in the literature that Yb based chelating agents have some
disadvantages when injected in vivo. 1. The large amount of Yb has to be injected
to obtain valuable diagnostic information. 2. They have minimal time in the blood