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Showing 5 results for Yousefnia
Dr. S.m.j. Mortazavi, M.a. Mosleh-Shirazi, M.r. Maheri, H. Yousefnia, S. Zolghadri, A. Haji-Pour,
Volume 5, Issue 3 (12-2007)
Abstract
Background: In megavoltage radiotherapy rooms, ordinary concrete is usually used due to its low construction costs, although higher density concrete are sometimes used, as well. The use of high-density concrete decreases the required thickness of the concrete barrier hence, its disadvantage is its high cost. In a nuclear reactor, neutron radiation is the most difficult to shield. A method for production of economic high-density concrete with appropriate engineering properties would be very useful. Materials and Methods: Galena (PbS) mineral was used to produce of a high-density concrete. Galena can be found in many parts of Iran. Two types of concrete mixes were produced. The water-to-concrete (w/c) ratios of the reference and galena concrete mixes were 0.53 and 0.25, respectively. To measure the gamma radiation attenuation of Galena concrete samples, they were exposed to a narrow beam of gamma rays emitted from a cobalt-60 therapy unit. Results: The Galena mineral used in this study had a density of 7400 kg/m3. The concrete samples had a density of 4800 kg/m3. The measured half value layer thickness of the Galena concrete samples for cobalt- 60 gamma rays was much less than that of ordinary concrete (2.6 cm compared to 6.0 cm). Furthermore, the galena concrete samples had significantly higher compressive strength (500 kg/cm2 compared to 300 kg/cm2). Conclusion: The Galena concrete samples made in our laboratories had showed good shielding/engineering properties in comparison with all samples made by using high-density materials other than depleted uranium. Based on the preliminary results, Galena concrete is maybe a suitable option where high-density concrete is required in megavoltage radiotherapy rooms as well as nuclear reactors.
A. Rabiei, M. Shamsaei, Dr. H. Yousefnia, A.r. Jalilian,
Volume 16, Issue 4 (10-2018)
Abstract
Background: In this study, human absorbed dose of a newly introduced bone imaging agent, 68Ga-(4-{[(bis(phosphonomethyl))carbamoyl]methyl}-7,10-bis(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl) acetic acid (68Ga-BPAMD), was estimated based on the rats data. Materials and Methods: 68Ga was obtained from the 68Ge/68Ga generator and it's radionuclidic and radiochemical purities were investigated. 68Ga-BPAMD complex was prepared at optimal conditions and the radiochemical purity was studied using instant thin layer chromatography (ITLC) method. The final preparation was injected to the normal rats and the biodistribution of the complex was followed up to 120 min post injection. The accumulated activity for animal organs was calculated. Finally, the human absorbed dose of the complexes was estimated by RADAR method. Results: 68Ga-BPAMD complex was prepared in high radiochemical purity (>99%, ITLC) at optimal conditions. The biodistribution of the complex demonstrated that the main remained radioactivity would considerably accumulate into the bones. The results showed the highest amounts of absorbed dose on the bone surface (0.253 mGy/MBq) and in the bone marrow (0.250 mGy/MBq), while the other organs would receive an insignificant absorbed dose after injection of the 68Ga-BPAMD complex. Conclusion: The comparison of dosimetric results for 68Ga-BPAMD with other complexes shows this complex is a safer agent for bone scanning. This property as well as other characteristics such as the high resolution images of the positron emission tomography (PET) scanning and the availability of 68Ga in the form of 68Ge/68Ga generator, make this complex as a suitable agent for PET bone imaging.
F. Habibi, R. Faghihi, S. Zolghadri, Ph.d., H. Yousefnia, S. Sina, F. I Mohammadpour-Ghaz,
Volume 20, Issue 1 (1-2022)
Abstract
Background: In recent years, Gallium-68 citrate has become known as an alternative radioisotope in nuclear medicine. As for its influences, 68Ga-based tracers have already been proposed as agents for positron emission tomography. In this research, the values of human absorbed dose for 68Ga-citrate and 67Ga-citrate were estimated using the medical internal radiation dose method based on biodistribution data in rats. Materials and Methods: 68Ga/67Ga-citrate was prepared from eluted 68Ga/67Ga-Cl3 and sodium citrate under multiple reaction forms. The biodistribution of 68Ga/67Ga–citrate radiolabeled compounds was investigated by dissection of five male rats at specific times after injection. The organs of the rats were removed and counted. Percentage of injected dose per gram was determined for each rat organ and the human absorbed dose was extrapolated using the rats’ data. Results: The results of estimating the human absorbed dose illustrate that 68Ga-citrate caused a much lower human absorbed dose compared with 67Ga-citrate. Conclusion: According to the results, it may be concluded that 68Ga-citrate, despite the better quality of PET imaging, is much safer in terms of absorption dose compared with 67Ga-citrate, and from this point of view, it is a more appropriate agent for imaging applications.
M. Hadisi, N. Vosoughi, Ph.d H. Yousefnia, A. Bahrami-Samani Bahrami-Samani, S. Zolghadri, R. Bagheri,
Volume 20, Issue 4 (10-2022)
Abstract
Background: PSMA is known as a suitable marker for imaging and targeted therapy of malignant tumors, especially prostate cancer. While; 177Lu-labeled PSMA is recognized as a promising compound for the treatment of metastatic castration-resistant prostate cancer patients, deployment of radionuclides with higher beta energy, including 188Re, can be useful for larger-sized tumors. However, the absorbed dose of the PSMA radiolabeled compound is substantial according to the considerable accumulation in the kidney. Materials and Methods: In this study; the biodistribution of 188Re-HYNIC-PSMA was studied in Wistar rats. ANACOMP software was utilized for compartmental modeling. The human absorbed dose of this new agent was assessed according to the rats’ biodistribution data using the RADAR method. Results: The highest accumulation of activity in Wistar rats’ organs were observed in the kidney. The human organs that received the highest absorbed dose were the kidneys and bladder wall with 0.69 and 0.46 mSv/MBq, respectively. Conclusion: The absorbed dose of 188Re-PSMA-617 in critical organs is comparable to the values of 177Lu-PSMA-617. 188Re-HYNIC-PSMA can be considered a safe compound for the treatment of PSMA expressing tumors.
N. Amraee, Ph.d., B. Alirezapour, M. Hosntalab, A. Hadadi, H. Yousefnia,
Volume 21, Issue 3 (7-2023)
Abstract
Background: Due to the excellent physical and biochemical characteristics of 68Ga, 68Ga-1,4,7-triazacy–clononane–glutaric acid– 4,7 acetic acid- arginyl-glycyl-aspartic acid- bombesin (68Ga-NODAGA-RGD-BBN) was prepared as a new positron emission tomography (PET) imaging agent, and afterward, the preclinical evaluation of this labeled peptide was studied. Materials and Methods: 68Ga radioisotope was extracted from a 68Ge/68Ga generator with high radionuclide, chemical and radiochemical purities. Then; the 68Ga-NODAGA-RGD-BBN radiolabeled complex was prepared at optimized conditions. The stability of the complex was evaluated in phosphate-buffered saline (PBS) for at least 2 h. Cell studies of the radiolabeled peptide were also assessed on the gastrin releasing peptide receptor (GRPR)-expressing cell line. Finally; the biodistribution and whole-body scan imaging study of 68Ga-NODAGA-RGD-BBN was studied in normal and tumor-bearing mice. Results: The biodistribution and whole-body scan imaging of the radiolabeled compound on GRPR-expressing tumor-bearing mice demonstrated the high uptake in the tumor site at all post-injection intervals. The biodistribution results also demonstrated the major excretion route of the complex is the urinary tract. Conclusions: 68Ga-NODAGA-RGD-BBN shows high potential for PET imaging of patients with GRPR-expressing tumors; however, more biological studies are still needed.
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