Preparation and biodistribution study of a [99m]Tc-labeled toxic fraction of Iranian mesobuthus eupeus scorption venom

Iranian scorpion species are classified in Buthidae and Scorpionidae with 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. Mesobuthus eupeus is the most common species in Iran. Its venom contains several toxin fractions which can affect the ion channel. In this study purification, labeling and biological evaluation of Mesobuthus eupeus scorpion venom are described. To separate different venom fractions, soluble venom was loaded on a chromatography column packed with sephadex G50 gel then the fractions were collected according to UV absorption at 280 nm wavelength. Toxic fraction [F3] was loaded on anionic ion exchanger resin [DEAE] and then on a cationic resins [CM]. Finally toxic fraction F319 was labeled with [99m]Tc and radiochemical analysis was determined by paper chromatography. The biodistribution was studied after injection into normal mice. Toxic fraction of venom was successfully obtained in purified form. Radiolabeling of venom was performed at high specific activity with radiochemical purity more than 95% which was stable for more than 4 h. Biodistribution studies in normal mice showed rapid clearance of compound from blood [2.64% ID at 4 h] and tissues except the kidneys [27% ID at 4 h]. As tissue distribution studies are very important for clinical use, results of this study suggest that [99m]Tc labeling of venom can be a useful tool for in vivo studies and is an excellent approach to follow the process of biodistribution and kinetics of toxins

novel dual energy CT-based attenuation correction method in PET/CT systems: a phantom study

In present PET/CT scanners, PET attenuation correction is performed by relying on the information given by CT scan. In the CT-based attenuation correction methods, dual-energy technique [DECT] is the most accurate approach, which has been limited due to the increasing patient dose. In this feasibility study, we have introduced a new method that can implement dual-energy technique with only a single energy CT scan. The implementation was done by CT scans of RANDO phantom at tube voltages of 80 kV[P] and 140 kV[P]. The acquired data was used to obtain conversion curves [which scale CT numbers at different kV[P] to each other], in three regions including lung tissue [HU<-100], soft tissue [-100200] for the combination of 80 kV[P] /140 kV[P]. Therefore, with having the CT image in one energy, we generate the CT image at the second energy [from now we call it virtual dual-energy technique] using these kV[P] conversion curves. The attenuation map at 511 ke[V] was generated using bilinear [the most commonly used method in commercially available PET/CT scanners], real dual-energy and virtual dual-energy technique in a polyethylene phantom. In the phantom study, the created attenuation map using mentioned methods are compared to the theoretical values calculated using XCOM cross section library. The results in the phantom data show 10.1%, 4.2% and 4.3% errors for bilinear, dual-energy and virtual dual-energy techniques respectively. Further evaluation using a larger patient data is underway to evaluate the potential of the technique in a clinical setting