Objective(s): The energy resolution of a cadmium-zinc-telluride (CZT) solid-state semiconductor detector is about 5%, and is superior to the resolution of the conventional Anger type detector which is 10%. Also, the window width of the high-energy part and of the low-energy part of a photo peak window can be changed separately. In this study, we used a semiconductor detector and examined the effects of changing energy window widths for 99mTc and 123 I simultaneous SPECT.Methods: The energy “centerline” for 99mTc was set at 140.5 keV and that for 123I at 159.0 keV. For 99mTc, the “low-energy-window width” was set to values that varied from 3% to 10% of 140.5 keV and the “high-energy-window width” were independently set to values that varied from 3% to 6% of 140.5 keV. For 123I, the “low energy-window-width” varied from 3% to 6% of 159.0 keV and the high-energy-window width from 3% to 10% of 159 keV. In this study we imaged the cardiac phantom, using single or dual radionuclide, changing energy window width, and comparing SPECT counts as well as crosstalk ratio.Results: The contamination to the 123I window from 99mTc (the crosstalk) was only 1% or less with cutoffs of 4% at lower part and 6% at upper part of 159KeV. On the other hand, the crosstalk from 123I photons into the 99mTc window mostly exceeded 20%. Therefore, in order to suppress the rate of contamination to 20% or less, 99mTc window cutoffs were set at 3% in upper part and 7% at lower part of 140.5 KeV. The semiconductor detector improves separation accuracy of the acquisition inherently at dual radionuclide imaging. In, this phantom study we simulated dual radionuclide simultaneous SPECT by 99mTc-tetrofosmin and 123 I-BMIPP.Conclusion: We suggest that dual radionuclide simultaneous SPECT of 99mTc and 123I using a CZT semiconductor detector is possible employing the recommended windows.

Background : Selenium-73 (T 1/2 =7.1h) and Selenium-75 (T 1/2 =119.8d) are useful RADIOISOTOPES in many research fields. The wide ranges of applications of these RADIOISOTOPES arose great interest for their production. Simultaneous production of 73 Se and 75 Se is more cost-effective and less time-consuming. Materials and Methods : 73 As (p, 3n) 73 Se and 75 As (p,n) 75 Se reactions were determined as the best choices for the production of 73 Se and 75 Se RADIOISOTOPES, according to the present facilities and conditions. The bombardment was performed by 30 MeV protons in Cyclone 30-IBA accelerator. ALICE and SRIM nuclear codes were used to determine the best energy and target thicknesses. Targets were specifically designed for simultaneous production of the RADIOISOTOPES as two consecutive pellets. Chemical processing was performed by no carrier added solvent extraction method. Radio-TLC was performed on polymer backed silica gel. A colorimetricmethod was used for chemical quality control. Radionuclidic quality control of the inal products was carried out by gamma spectroscopy with HPGe detector. Results: The production yield was 5.3 mCi/µAh for 73 Se and 50 µCi/µAh and 678 µCi/µAh for 75 Se in the first and second pellets respectively. The specific activity of 73 Se was 1.06 mCi/ml and that of 75 Se was 135.6 µCi/ml after one hour of proton bombardment with a current of 5µA. The isotopic purity of 73 Se was 99% in the first pellet and that of 75 Se was 100% in the second, just after the end of bombardment. A 0.04 ppm colorimetric method showed no traces of arsenic in the final product. Conclusion : The quick and inexpensive procedure used in this research, resulted in high yields,high chemical and high isotopic purity for both RADIOISOTOPES. It can be considered as the method of choice for simultaneous production of 73 Se and 75 Se

Introduction: 238U decays with alpha particles emission into 234Th and the series ends with 206Pb. The unstable nucleus loses the energy with emitting ionizing alpha particles for reaching a stable state. It is undergoing alpha decay with decay energy (4. 679 MeV). Alpha particles enter the human and animal bodies through inhalation of air or ingestion of contaminated food and water. This study aimed to perform a radiological analysis on the natural alpha particle emission rates of the human teeth as the biomarkers of radiation exposure and environmental pollution. Materials and Methods: This study was conducted on 68 teeth samples of 27 males and 41 females collected from the hospitals distributed across Najaf governorate, including many districts in Iraq. Alpha particle emission rates were measured using CR-39 nuclear track detector. Results: The mean emission rate of alpha particles in the female teeth was 0. 0396± 0. 0070 mBq cm-2, which was relatively higher than that in the male teeth (0. 0390± 0. 0048 mBq cm-2). Nevertheless, there was no significant difference between the female and male teeth regarding the emission rate of alpha particles. Furthermore, the emission rate of alpha particles in the teeth of the samples taken from Kufa (0. 0417± 0. 0057 mBq cm-2) was higher than those obtained from Najaf (0. 0384± 0. 0053 mBq cm-2). Conclusion: As the findings of this study revealed, Najaf governorate had a lower emission rate of alpha particles as compared to other sites of the worldwide. Therefore, it could be concluded that there is no negative consequence threatening the people’ s health in this regard.