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The aim of this study was to propose a new dual-modality nanoprobe for positron emission tomography/magnetic resonance imaging (PET/MRI) for the early diagnosis of breast cancer. For synthesis of the nanoprobe, polyethylene glycol-coated ultra-small superparamagnetic iron-oxide nanoparticles (USPION) armed with NODA-GA chelate and grafted with bombesin (BBN) were radiolabeled with 68Ga. After characterization, in vitro studies to evaluate the cell binding affinity of the nanoprobe were done by performing Perl's Prussian blue cell staining and MRI imaging. Finally, for in vivo studies, magnetic resonance images were taken in SCID mice bearing breast cancer tumor pre- and post-injection, and a multimodal nanoScan PET/computed tomography was used to perform preclinical imaging of the radiolabeled nanoparticles. Afterwards, a biodistribution study was done on sacrificed mice. The results showed that the highest r1 and r2 values were measured for USPIONs at 20 and 60 MHz, respectively. From the in vitro studies, the optical density of the cells after incubation increased with the increase of the iron concentration and the duration of incubation. However, the T2 values decreased when the iron concentration increased. Furthermore, from in vivo studies, the T2 and signal intensity decreased during the elapsed time post-injection in the tumor area. In this study, the in vitro studies showed that the affinity of cancer cells to nanoprobe increases meaningfully after conjugation with BBN, and also by increasing the duration of incubation and the iron concentration. Meanwhile, the in vivo results confirmed that the blood clearance of the nanoprobe happened during the first 120 min post-injection of the radiolabeled nanoprobe and also confirmed the targeting ability of that to a gastrin-releasing peptide receptor positive tumor. [ABSTRACT FROM AUTHOR]

Byline: Saeed. Shanehsazzadeh, Mohammad. Oghabian, Barry. Allen, Massoud. Amanlou, Afshin. Masoudi, Fariba. Daha In order to evaluate the long-term viability, the iron content stability, and the labeling efficiency of mammalian [...]

The purpose of this study is to evaluate the biodistribution of polyethylene glycol (PEG) coated superparamagnetic iron oxide nanoparticles radiolabeled with Ga in normal mice after intravenous administration of this probe. Three mice were sacrificed at specific time intervals. The biodistribution data revealed high uptake by liver and spleen (60.62 and 12.65 %ID/g at 120 min post injection for liver and spleen, respectively). The clearance of other organs was fast. These results suggest that Ga-PEG-SPIONs has magnificent capabilities for applying in (PET-MRI) as a theranostic agent for detection of liver and spleen malignancies. [ABSTRACT FROM AUTHOR]

Introduction: Recent studies show that porphyrin derivatives have interesting pharmacological and photodynamic properties and wide range of usage in photodynamic therapy treatment. This study describes the preparation, biodistribution and absorbed dose prediction of [111In] labeled 5, 10, 15, 20-tetra phenyl porphyrin (TPP) in human organs, based on rats' biodistribution data. Methods: Five rats were sacrificed at each exact time intervals (2, 4 and 24 h post injection) and the percentage of injected dose per gram of each organ was measured by direct counting from rats data from 12 harvested organs. The Medical Internal Radiation Dose (MIRD) formulation was applied to extrapolate from rats to human and to project the absorbed radiation dose for various organs in humans. Results: From rat data we estimated that injection of [111In] TPP into the humans would result in an estimated effective absorbed dose of 0.09 mSv/MBq in the whole body. While the highest effective absorbed dose for 111In-TPP was in the heart wall (0.22 mSv), the organs that received the next highest doses were the Kidneys (0.06 mSv), thymus (0.04 mSv) and lungs (0.03 mSv). Conclusions: The skin dose will four times higher compare to the other 111In compounds, which was due to magnificent skin uptakes. According to the fast wash-out, tumor avidity and the short half-life, [111In] can be a suitable candidate for labeling of photo dynamic therapy (PDT) agents as a tracer for accurate biological evaluation of other PDT agents such as Photofrin and its homologs. [ABSTRACT FROM AUTHOR]

This study describes the preparation, biodistribution of 177Lu-DTPA-SPIO after intravenous injection in rats. The chelator DTPA dianhydride was conjugated to SPIO NPs using a small modification of the well-known cyclic anhydride method. Conjugation was done at a 1:2 (SPIO : ccDTPA) molar ratio. Conjugation reaction was purified with Magnetic assorting column (MACs) using high gradient magnetic field following incubation, the radio labeled conjugate was checked using RTLC method for labeling and purity checked. The RTLC showed that labeling yield was above 99% after purification and the compound have good in-vitro stabilities until 48 h post injection in the presence of human serum. The biodistribution of 177Lu-DTPA-SPIO in rats showed dramatic uptake in the reticuloendothelial system (RES) and their clearance is so fast in other organs especially in the blood. In conclusion, due to high uptakes of this radiotracer in the liver and spleen and their fast clearance from other tissues, especially in blood, it is suggested that this radiotracer would be suitable for RES studies. [ABSTRACT FROM AUTHOR]

In this study, Lu-(4-{[(bis(phosphonomethyl))carbamoyl]methyl}-7,10-bis(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl) acetic acid (Lu-BPAMD) was successfully prepared. The quality control, partition coefficient, hydroxyapatite binding assay and stability of the complex were determined. For better comparison, biodistribution patterns of Lu-BPAMD and Lu-EDTMP complexes were compared in same animal model. Lu-BPAMD was prepared with high radiochemical purity (>93 %) and specific activity of 534 GBq/mmol at the optimal conditions. Comparative study between Lu-BPAMD and Lu-EDTMP indicated higher bone uptake and lesser accumulation in the other organs for Lu-BPAMD. Lu-BPAMD can be considered as a promising agent for bone pain palliation in the near future. [ABSTRACT FROM AUTHOR]