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AIM: The aim of this study is to find an optimum material to protect garment for protection against 99Tcm radionuclide. MATERIALS AND METHODS: Monte Carlo simulation code was applied to investigate radiation attenuation of 13 shielding materials including: Ba, gray Sn, white Sn, Sb, Bi, Bi2O3, BaSO4, Sn/W, Sb/W, Pb and W with thicknesses of 0.5 and 1 mm to determine an optimum protective garment material in nuclear medicine against 99Tcm. Furthermore, the dose enhancement on the staff body was investigated for shielding materials such as tungsten and lead. RESULTS: The findings of the simulations show that the maximum and minimum attenuation obtained with thicknesses of 1 mm W and 1 mm BaSO4 were 96.46% and 14.2%, respectively. The results also demonstrate that tungsten does not cause any dose enhancement on staff body but this is not true for lead. Tungsten provides the highest radiation attenuation without dose enhancement on the body of staff. CONCLUSION: Among materials evaluated, tungsten is the optimum material and it can be applied for the design of protective garment for nuclear medicine staff against 99Tcm.
RESUMO
BACKGROUND AND OBJECTIVE: Professional radiation workers are occupationally exposed to long-term low levels of ionizing radiation. Occupational health hazards from radiation exposure, in a large occupational segment of the population, are of special concern. Biological dosimetry can be performed in addition to physical dosimetry with the aim of individual dose assessment and biological effects. METHODS: In this biodosimetry study, some hematological parameters have been examined in 40 exposed and 40 control subjects who were matched by gender, age and occupational records (±3 years) in Kermanshah hospitals in Iran (2013-2014). The occupational radiation dose was measured by personal dosimetry device (film badges). The data was analyzed using SPSS V.20 and statistical tests such as two-sided Student's t-test. RESULTS: Exposed subjects had a median exposure of 0.68±1.58 mSv/year by film badge dosimetry. Radiation workers with at least a 10-year record showed lower values of Mean Hemoglobin (Hb) and Mean Corpuscular Volume (MCV) compared to the control group (p<0.05). The mean value of Red Blood Cells (RBCs) in personnel working in Radiology departments seemed to show decrease in comparison with other radiation workers. CONCLUSION: Although the radiation absorbed doses were below the permissible limits based on the ICRP, this study showed the role of low-level chronic exposure in decreasing Hb and MCV in the blood of radiation workers with at least 10 years records. Therefore, the findings from the present study suggest that monitoring of hematological parameters of radiation workers can be useful as biological dosimeter, and also the exposed medical personnel should carefully follow the radiation protection instructions and radiation exposure should be minimized as possible.
RESUMO
OBJECTIVE: In this study the relationship between degree of spasticity and strength of knee extensor and ankle plantar flexor muscles of post stroke hemiparetic patients has been investigated. MATERIALS & METHODS: The participants of this study were 40 stroke patients whose elapsed time of stroke onset was at least 3 months. Their age averaged 59 years. Spasticity was measured with the Modified Ashworth Scale. Isokinetic muscle strength was measured with an isokinetic dynamometer. Two methods of torque normalization - subtractive and weight based normalization - were used for comparing torques among participants. RESULTS: Kendall's tau-b coefficient was calculated for investigating this relationship. This coefficient was not significant for the relationship between weight based normalized data and modified Ashworth scale (MAS) in any of each muscle groups (α = 0.05). This coefficient was significant for the relationship between the subtractive normalization method and MAS in knee extensors (P = 0.005, α = 0.01) and ankle plantar flexors (P = 0.002, α = 0.01). CONCLUSION: This study suggests a negative relationship between spasticity and muscle strength and provided evidence that spastic muscles are weaker.
