Introduction: Registration of SCATTERed photons along with the primary photons is a major cause of degrading image quality and quantitative accuracy in single photon emission tomography. To deal with the problem some techniques have been developed. Deconvolution is the technique that considers the effect of SCATTER as convolution of the primary photons with a SCATTER function. Therefore the image of the non-SCATTERed photons could be extracted from a mixed image of SCATTERed and non-SCATTERed photons using a deconvolution technique. Methods and materials: In this study the complex wavelet wiener deconvolution was used as a method of deconvolution. We used Monte Carlo generated phantoms to simulate the SCATTERed and SCATTER free Images. Results: This simulated study showed that the method improves the image quality and quantitative accuracy up to 1.5 dB in comparison to SCATTER reduction in the energy window of 20%. Conclusion: Complex wavelet wiener deconvolution has the potential to be used as an efficient SCATTER compensation method. Other deconvolution methods such as iterative may also be used on the high pass sub-bands components of complex wavelet decomposition as a complementary method.      

Introduction: Myocardial perfusion imaging is a nuclear medicine imaging method that is used to detect coronary artery diseases. One of the main sources of error in this imaging method is the detection of Compton SCATTERed photons in the photopeak energy window used for data acquisition. This results in the degradation of the image contrast, and therefore decreases the diagnostic accuracy. Material and Methods: In this study, the efficiency of dual-energy window (DEW) correction method regarding the reduction of the undesirable influence of SCATTERing was investigated using the images acquired from the 3D-NCAT simulated phantom, and a group of patients (18 males and 27 females) in both rest and stressful situations. To evaluate the SCATTER correction method, the image contrasts are calculated before and after applying the SCATTER correction. Results: The results obtained from this study indicated that the calculated image contrasts enhanced by applying the SCATTER correction in both simulation and patient studies. In the simulation study, the relative values of increase in image contrast are about 10. 15% and 12. 58% when using a k value equal to 0. 5, and the linear fitting method, respectively. In the patient study, the relative values of increase in image contrasts regarding the rest and stress situations were about 13. 63% and 10. 84% for females and 12. 03% and 10. 56% for males, respectively. Conclusion: The utilization of the DEW method for SCATTER correction of cardiac SPECT images results in an increase in the image contrast and the improvement of the image quality.

Background: Tomography can be corrected by SCATTER correction (SC) to improve image quality.Siemens SPECT has several function of optional marked SC in the tomographic image reconstruction.The aim of this research is to distinguish the difference between the different function settings.Materials and Methods: "SC‐Tc‐99m‐NMG" energy peak of Brain model tomographic data were used.Dual lsotopes loaded in "Tomo Reconstruction" activity primary and secondary energy peak to analyze separately in 2 groups. Single lsotopes loaded in "Tomo Reconstruction" activity divided into SC and NSC to analyze separately in 2 groups. Dual lsotopes loaded in "AutoRecon" activity divided into SC and NSC to analyze separately in 2 groups. Limited by "AutoRecon" activity, we use Flash 3D (8, 8) gaussian 8.00 function to reconstruct and analyze the range of image to the largest extent.Results: With all 128 layers summed in axial section, the average radioactive counts of the 6 groups respectively were 10092.30±24.20, 4199.40±13.41, 10092.60±24.95, 10084.30±16.05, 8151.60±20.64 and 10238.80±20.64, and the maximum counts were 10328, 3621, 10370, 10338, 8546 and 10445. Except secondary energy peak data, others met the clinical requirements through visual assessment brain SPECT. There was no statistically significant differences between a, c, d groups after paired T test.Conclusions: SC could only be done with Flash 3D function in “AutoRecon” activity using Siemens syngo V60B.

In this paper we develop a new hybrid metaheuristic algorithm based on the SCATTER search approach to solve the well-known resource-constrained project scheduling problem. This algorithm combines two solutions from SCATTER search to build a set of precedence feasible activity lists and select some of them as children for the new population. We use the idea presented in the forward/backward improvement technique to define two types of schedule, direct and reverse, and the members of the sequential populations change alternately between these two types of schedule. Extensive computational tests were performed on standard benchmark datasets and the results are compared with the best available results. Comparative computational tests indicate that our procedure is a very effective metaheuristic algorithm.

Introduction: This study aimed to investigate the absorbed dose of SCATTER radiation in coronary angiography. Material and Methods: The SCATTER radiation dose was measured for 20 patients at four different heights (50, 100, 150, and 165 cm) from the floor. The spatial dose was measured by RTI Piranha r100b solid-state dose probe at different points around the patient in an actual clinical situation and with a phantom. Also, the measurement was repeated using a designed phantom in fluoroscopy and cine mode in posterior anterior (PA), left lateral (LLAT), left posterior oblique (LPO45°, ), right posterior oblique (RPO45°, ), and right-lateral (RLAT)projections. Organ-absorbed doses were normalized to dose area product (DAP). Results: The dose rate at different heights between the projections on the patient and the phantom as well as organ dose DAP conversion coefficients were different (p˂, 0. 05). It was found that the dose rate changes in fluoroscopic mode compared to cine mode are significantly different (p = 0. 001). The dose rate in cine mode is approximately four times that in fluoroscopy mode. The dose rate around the cardiologist's waist could be reduced by 37 –,43 % with a displacement of 20cm away. In this study, the effective dose rate received by the cardiologist’, s eyes was higher than those reported by ICRP. Conclusion: Taking a suitable projection could reduce the dose rate delivered to the angiography team. Further studies should be conducted about the effect of different projections with the same clinical use on dose distribution in coronary angiography to provide the best working conditions for physicians and staff.