Public member dose assessment of Bushehr Nuclear Power Plant under normal operation by modeling the fallout from stack using the HYSPLIT atmospheric dispersion model.

In this work, public dose resulting from fission products released from Bushehr Nuclear Power Plant (BNPP) under normal operation is assessed. Due to the long range transport of radionuclides in this work (80 km) and considering terrain and meteorological data, HYbrid Single-Particle Lagrangian Integrated Trajectory (HYsplit) model, which uses three dimensional long-range numerical models, has been employed to calculate atmospheric dispersion. Annual effective dose calculation is carried out for inhalation, ingestion, and external exposure pathways in 16directions and within 80 km around the site for representative person. The results showed the maximum dose of inhalation and external exposure for adults is 3.8 × 10-8Sv/y in the SE direction and distance of 600 m from the BNPP site which is less than ICRP 103 recommended dose limit (1 mSv). Children and infants' doses are higher in comparison with adults, although they are less than 1 mSv. Ingestion dose percentage in the total dose is less than 0.1%. The results of this study underestimate the Final Safety Analysis Report ofBNPP-1 (FSAR)data.

A novel energy mapping approach for CT-based attenuation correction in PET.

PURPOSE: Dual-energy CT (DECT) is arguably the most accurate energy mapping technique in CT-based attenuation correction (CTAC) implemented on hybrid PET/CT systems. However, this approach is not attractive for clinical use owing to increased patient dose. The authors propose a novel energy mapping approach referred to as virtual DECT (VDECT) taking advantage of the DECT formulation but using CT data acquired at a single energy (kV(P)). For this purpose, the CT image acquired at one energy is used to generate the CT image at a second energy using calculated kV(P) conversion curves derived from phantom studies. METHODS: The attenuation map (µ-map) at 511 keV was generated for the XCAT phantom and clinical studies using the bilinear, DECT, and VDECT techniques. The generated µ-maps at 511 keV are compared to the reference derived from the XCAT phantom serving as ground truth. PET data generated from a predefined activity map for the XCAT phantom were then corrected for attenuation using µ-maps generated using the different energy mapping approaches. In addition, the generated µ-maps using the above described methods for a cylindrical polyethylene phantom containing different concentrations of K(2)HPO(4) in water were compared to actual attenuation coefficients. Likewise, CT images of five clinical whole-body studies were used to generate µ-maps using the various energy-mapping approaches were compared with µ-maps acquired at 511 keV using (68)Ge/(68)Ga rod sources for the clinical studies. RESULTS: The results of phantom studies demonstrate that the proposed method is more accurate than the bilinear technique. All three µ-maps yielded almost similar results for soft and lung tissues whereas for bone tissues, the DECT and the VDECT methods produced a much smaller mean relative difference (3.0% and 2.8%, respectively) than the bilinear approach (11.8%). Likewise, the comparison of PET images corrected for attenuation using the various methods showed that the proposed method provides better accuracy (6.5%) than the bilinear method (13.4%). Clinical studies further demonstrated that, compared to the bilinear method, the VDECT approach has better agreement for bony structures with the DECT technique (1.5% versus 8.9%) and transmission scanning (8.8% versus 17.7%). CONCLUSIONS: It was concluded that the proposed method outperforms the bilinear method especially in bony structures. Further evaluation using a large clinical PET/CT database is underway to evaluate the potential of the technique in a clinical setting.

Comparison of Enterocystoplasty and Ureterocystoplasty before Kidney Transplantation.

BACKGROUND: Augmentation cystoplasty before or after renal transplantation is an option for patients with end-stage renal disease who are candidates for renal transplantation and have low capacity and poorly compliant bladders. OBJECTIVE: To compare two surgical methods of bladder augmentation-enterocystoplasty (EC) and ureterocystoplasty (UC)-before kidney transplantation, and their outcome with that in kidney recipients who had normal bladder function. METHODS: During a 20-year period (1988-2008), 1406 renal transplantation were performed in our center by our team. In 16 patients having a mean age of 18.8 years, EC (group A) and in 8 with mean age of 11.5 years, UC (group B) were performed before renal transplantation. These two groups were compared with a control group of 30 recipients with normal bladder (group C) with mean age of 15.6 years, for kidney function, graft and patient survival, and the frequency of urinary tract infection (UTI). RESULTS: There was normal graft function in 11 of group A, 7 of group B, and 24 of group C patients, during a mean follow-up of 73.1 months. The mean±SD serum creatinine in follow-up was 1.72±0.31, 1.37±0.13 and 1.33±0.59 mg/dL in groups A, B and C, respectively. No statistically significant differences were observed among the 3 studied groups in terms of 1-, 5- and 10-year graft and patient survivals. Number of episodes of febrile UTI requiring hospitalization was 23, 6 and 2 in groups A, B and C, respectively. UTI and urosepsis were significantly more frequent in group A than groups B (p=0.025) and C (p=0.001); no significant difference was observed in the frequency between groups B and C (p=0.310). CONCLUSION: Both EC and UC are equally recommended before renal transplantation for reconstruction of the lower urinary tract; use of each method should be individualized depending on specific conditions of recipient.

Serum homocysteine in deep venous thrombosis, peripheral atherosclerosis and healthy Iranians: a case-control study.

This study was aimed to evaluate the association of serum homocysteine with peripheral atherosclerosis and deep vein thrombosis in an Iranian population complaining from vascular symptoms in lower limbs referred to a university general hospital in the capital of Iran. The study design was case-control. Deep vein thrombosis and atherosclerosis groups were, respectively consisted of 25 patients presenting with signs and symptoms of deep vein thrombosis whom disease was confirmed by duplex ultrasonography and 25 patients presenting with signs and symptoms of chronic arterial insufficiency who were candidate for arterial reconstruction whom disease was confirmed by angiography. The control group was consisted of 25 persons selected among relatives accompanying the traumatic patients admitted in the general surgery ward of the same hospital. The age of atherosclerosis, DVT and control group were 61 +/- 14, 47 +/- 16 and 40 +/- 14, respectively. The serum level of homocysteine was higher in males (p < 0.01) except for atherosclerotic patients. The prevalence of high homocysteine was 15% (control), 36% (DVT) and 56% (atherosclerosis) among females and 75% (control), 73% (DVT) and 56% (atherosclerosis) among males. The serum homocysteine in the control group which was representative of Tehran population who do not take vitamin B supplements was unexpectedly high. It seems that fortification of popular foodstuffs should be considered for Tehran. The association between homocysteine and atherosclerosis and deep vein thrombosis was not confirmed in this study especially for men who had higher serum homocysteine than women. It is possible that this association fades away in populations with high prevalence of hyperhomocysteinema.

Concomitant carotid endarterectomy and coronary artery bypass grafting versus staged carotid stenting followed by coronary artery bypass grafting.

AIM: Significant carotid stenosis (>or=70%) in patients undergoing coronary artery bypass grafting (CABG) can increase the risk of perioperative cerebral vascular accident (CVA). In this study, we compared the results of two common operative strategies: concomitant carotid endarterectomy and CABG versus carotid stenting and CABG. METHODS: This cohort study was conducted from January 2001 to September 2006. Significant carotid artery stenosis was detected in patients who were candidates for CABG at the Tehran Heart Center. The stenosis was detected by carotid Doppler screening and was confirmed by magnetic resonance angiography. Reluctant patients or those with previous major CVA, significant bilateral carotid stenosis and intracranial lesions were excluded. Patients were divided into 2 groups. Group A underwent concomitant carotid endarterectomy and CABG (n=19), while carotid stenting and CABG were done in group B (n=28). RESULTS: The mean age in group A was 67.37+/-7.09 years and 65.57+/-8.13 years in group B. The mean hospital stay (days) was 18.68+/-7.95 in group A and 26.35+/-77.04 in group B (P=0.01). The median charge was dollars 252.79 in group A and dollars 2206.66 in group B (P <0.0001). There was a significant difference in frequency of hypotension and bradycardia between the 2 groups (P <0.05). There were 2 cases of in-hospital mortality in each group (10.5% and 7.1%, respectively). Two postoperative strokes occurred in group A and 3 in group B (10.5% and 10.7%, respectively). CONCLUSION: Concomitant carotid endarterectomy and CABG is as safe as carotid stenting and CABG, with fewer neurologic events and less hypotension, bradycardia, cost and shorter hospital stay.

Characteristics and outcome of injured patients treated in urban trauma centers in Iran.

BACKGROUND: Because of the need to improve the quality of care of trauma patients in our country, we decided to evaluate the epidemiology and find the most powerful tool for prediction of survival. The Trauma and Injury Severity Score (TRISS) has been known as conventional method for this purpose. We planned to test its ability for prediction of survival of our trauma patients, and also we wanted to compare its ability with the New Injury Severity Score (NISS) in combination with Revised Trauma Score (RTS) and age. We used the most suitable model to evaluate the trauma care in our centers. METHODS: From the Tehran University data registry on trauma patients of three different hospitals during 1 year, we selected trauma patients admitted to hospital for at least 1 day and all those patients who were declared dead at the emergency department. Epidemiologic description of patients has been given and evaluation of TRISS and (NISS + RTS + age) for prediction of survival has been performed. We determined factors affecting mortality and morbidity, evaluated hospitals, and analyzed patients admitted directly and the patients transferred from other hospitals. RESULTS: A total of 2,662 patients had complete data necessary for the calculation of probability of survival based on the TRISS method. The population at risk for trauma was the young, especially students and industrial workers. The major mechanisms of trauma were road traffic crashes and falls. The time expenditure and means of transportation as well as the time of stay in emergency department all seemed to be far less than optimal. We found that TRISS has higher performance than (NISS + RTS + age). CONCLUSION: Based on our descriptive findings, we proposed some suggestions that seem to be necessary for improvement of trauma care in our centers. Among them were improved measures for prehospital service, and emergency department and other health care units of our centers. The findings of this study suggest that conducting trauma surgery training programs and direct transportation to trauma centers can improve the outcome of trauma patients. We conclude that small sample size, mixing penetrating trauma cases with blunt trauma cases, and differences in the mechanism of trauma between study populations may be responsible for the difference between our results and others.