Shielding evaluation of a typical radiography department: a comparison between NCRP reports No.49 and 147

Designing and shielding of an appropriate radiography room has been one of the major concerns of radiation scientists since the first decade after the invention of X-rays. Recently, report no.147 of National Council on Radiation Protection and Measurements [NCRP] has been published. In this study the researchers have investigated the effect of new report recommendations on primary and secondary barriers thicknesses in comparison to NCRP 49, and 116 recommendations. To calculate the walls thickness of a conventional radiography room, the workload of a radiography room of a university hospital was determined by recording the number of exposures, mAs and kVp for each patient during six months. Three types of calculations were done: [1] Using NCRP 49 formulations and dose limits [2] Using the NCRP 49 formulations and dose NCRP 116 dose limits and [3] Using the NCRP 147 recommendations. The estimated workload was 172 mA min wk [-1] for the studied radiography room which was slightly lower than the workload recommended by NCRP 147. The results showed that using the NCRP 49 formulation and NCRP116 dose limits, the barriers thickness increases substantially. Moreover, the dose limits were lower in NCRP 147, using the third method. The primary barrier the results of the two methods [1] and [3] did not differ and remained the same. Application of NCRP 49 and NCRP 116 dose limits for radiography room shielding [second method] overestimated the primary and secondary barriers thickness, significantly. But, applying NCRP 147, not only the new dose limits were considered, but also the cost of primary barrier construction was reduced

[Evaluation of total plasma homocysteine, folic acid and vitamin B12 in 25-64 aged inhabitants of Tehran University of medical sciences population lab region]

Introduction: elevated plasma total homocysteine is an independent risk factor for cardiovascular disease and a sensitive marker of vitamin B12 and folate insufficiency. Folate and vitamin B12 have a protective effect on cardiovascular disease. This effect may be partly explained by mechanisms independent of homocysteine. This survey is the first population based study to evaluate the plasma total homocysteine, folic acid and vitamin B12 in 1214 healthy Iranian persons

Methods: this study which was a part of the Cardiovascular Risk Factors Survey in the Population Lab region, has been designed and conducted based on MONICA/WHO project. A total of 1214 people have been recruited and assessed on serum homocysteine, folic acid and vitamin B12 with interview, questionnaires, examination and blood sampling. Blood samples were gathered in Venoject tubes and analyzed according to standard methods

Results: the variables were assessed in 1214 participants include 428 men [35.3%] and 786 women [64.7%]. Prevalence of hyperhomocysteinemia was 96.4% in men and 83.3% in women [p<0.0001]. Geometric mean of serum homocysteine was 19.02 +/- 1.46 [micro]mol/l in men and 14.05+/- 1.45 [micro]mol/l in women [p<0.004] and increased with age. Folic acid deficiency was seen in 527 [98.9%] men and 833 women [98.0%]. 161 [30.1%]men and 232[27.2%] women had vitamin B12 deficiency

Conclusion: these results revealed that the prevalence of hyperhomocysteinemia, folic acid and vitamin B12 deficiency was higher than other communities considerably. Preventive interventions as food fortification with folic acid is necessary