Internal absorbed dose calculation in body organs due to injection of Rhenium-188 labeled to Mu-9 antibody.

The use of radiopharmaceuticals has gained a special place in the diagnosis and treatment of cancers and evaluation of the function of different organs of the body. In this study, the absorbed dose distribution of organs after injection of 188Re-Mu-9 has been investigated using MIRD method and MCNP-4C simulation code. The 188Re-Mu-9 labeled was injected the mouse body and the amount of 188Re-labeled accumulation was evaluated after 1, 4 and 2 4 h. Having a map of the distribution of radiopharmaceutical activity in the animal body, it is possible to convert it into a human model to obtain the internal dose received by 188Re-Mu-9 injection using the MIRD calculation method and the MCNP simulation code. According to the results of the study, the animal/human model can be acceptable method for dose estimation of antibody-based radiopharmaceuticals.

Internal dosimetry studies of 177Lu-BBN-GABA-DOTA, as a cancer therapy agent, in human tissues based on animal data.

The goal of using radiopharmaceuticals for therapeutic purposes is twofold: first, the most damage to cancer cells and, second, the most negligible dose transfers to healthy tissues. As 177Lu has the potential to cure a wide range of malignancies due to its varied range of beta energies, 177Lu-BBN-GABA-DOTA has been developed for therapeutic applications. In addition, 177Lu-BBN-GABA-DOTA can be over-expressed on gastrin-releasing peptide (GRP) receptors of the prostate, breast, small cell lung cancer, gastric, and colon tumors. The purpose of this study was to calculate the amount of dose absorption in human body organs using medical internal radiation dose (MIRD) and GATE code methods, after animal injection. In this study, the amount of absorbed dose in different organs (spleen, kidney, Lung, Pancreas, Heart, Adrenal, Intestine, Stomach, and Liver) were calculated for 1-MBq accumulation of 177Lu-BBN-GABA-DOTA in source organs (spleen, kidney, Lung, Pancreas, Heart, Adrenal, Intestine, Stomach, and Liver) using Monte Carlo Simulation (GATE code) with Zubal phantom. Moreover, compared with MIRD method, the results of the simulation showed considerable consistency. It was estimated that a 1-MBq administration of 177Lu-BBN-GABA-DOTA to the human body would result in an absorbed dose of 1.07E-02 mGy and 4.97E-02 (MIRD method) and 1.26E-02 mGy and 5.19E-02 (Gate code) in the Pancreas and adrenal 120 h after injection, respectively. The highest and lowest percentage differences between MIRD and Gate results are related to the Pancreas and spleen, respectively. Finally, the results showed that there is a good agreement between MIRD method and Gate code simulation for absorbed dose estimation.

Internal dosimetry studies of 170Tm-EDTMP complex, as a bone pain palliation agent, in human tissues based on animal data.

Radiopharmaceuticals with therapeutic applications are designed to deliver high doses of radiation to target organs with minimizing unwanted radiation to healthy tissues. Owing to the potential of targeted radiotherapy to treat a wide range of malignancies, 170Tm -EDTMP was developed for possible therapeutic applications. This study describes absorbed dose prediction of 170Tm-EDTMP in human organs after animal injection which is determined via medical internal radiation dose (MIRD) and MCNP-4C code methods. It was estimated that a 1-MBq administration of 170Tm-EDTMP into the human body would result in an absorbed dose of 37.9 mGy (MIRD method) and 38.02 mGy (MCNP-4C code) in the bone surface after 60 days post injection. Highest and lowest difference between MIRD and MCNP results are for lung and bone surface respectively. Finally, the results show that there is a good agreement between MIRD method and MCNP-4C simulation code for absorbed dose estimation.

Comparison of two purified toxic fractions from Mesobuthus eupeus scorpion venom

Iranian scorpions belong mainly to the Buthidae and Scorpionidae families, distributed into 16 genera and 25 species. In Iran, similar to other parts of the world, there are a few known species of scorpions responsible for severe envenoming; amongst which Mesobuthus eupeus is the most common. Its venom contains several toxin fractions that may affect the ion channel. In the present study purification, labeling and biological evaluation of M. eupeus venom are described. For separation, soluble venom was loaded on a chromatography column packed with Sephadex G-50 gel. Subsequently, the fractions were collected according to UV absorption at a wavelength of 280 nm. Toxic fraction (F3) was loaded on an anionic ion exchanger resin and then on a cationic resin. Finally, toxic subfractions F3.1.6 and F3.1.9 were labeled with 99mTc and injected into normal mice to distinguish excretion pathway. The venom toxic fraction was successfully obtained in its purified form. Radiolabeling of toxic fractions was performed at high specific activity with radiochemical purity of more than 97 and 95 percent respectively for F3.1.6 and F3.1.9. Biodistribution studies in normal mice with two toxic fractions usually show rapid clearance of the compounds from blood and tissue except for kidneys. Since tissue distribution studies are very important for clinical purpose, the present findings suggest that 99mTc labeling of venom is a useful tool for in vivo studies and comprises an excellent approach to monitoring the process of biodistribution and kinetics of toxins.(AU)