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Objective To detect the positive rates of antibodies against avian influenza virus (AIV) subtypes H5, H6, H7 and H9 among people in poultry occupations in Guangdong province and to analyze the transmission of various subtypes of AIV from poultry to human contacts for the prevention and control of novel AIV infection in human beings.Methods Serum specimens were collected from 1066 peo-ple in poultry occupations ( occupational group) and 205 people not in poultry occupations ( non-occupational group) in 10 cities of Guangdong province.The inactivated AIV strains, isolated from poultry or environment of Guangdong province, were used as antigens to detect antibodies against AIV subtypes H5, H6, H7 and H9 by using the hemagglutination inhibition ( HI) assay.Results The positive rates of antibodies against AIV subtypes H5, H6, H7 and H9 carried by people from the occupational group were respectively 0.44%, 0%, 0.30%and 0.30%in 2013 and 1.08%, 0.0%, 0.0%and 0.27%in 2014.Only the anti-H9 anti-bodies were detected in serum samples collected form people in the non-occupational group in 2013 with a positive rate of 0.95%.No significant differences with the positive rates of anti-AIV antibodies were found between the occupational group and the non-occupational group.However, the geometric mean titer ( GMT) of anti-AVI antibodies in people from the occupational group was higher than that of the non-occupational group.Conclusion Although a grand spread of AIV from avian to human is not likely to happen yet, con-tacting with poultry is the risk factor for AIV infection in Guangdong population.A long-term surveillance of anti-AIV antibodies in serum should be strengthened among people in poultry occupations for the timely pre-vention and control of novel AIV outbreak.
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<p><b>OBJECTIVE</b>To investigate the impact of metal implants with different materials on radiation dose distribution based on film measurement method.</p><p><b>METHODS</b>Titanium plate, titanium intramedullary pin and stainless steel plate were set into phantom and irradiated separately by 6 MV and 15 MV X ray from linear accelerator. Dose distributions derived from different materials metal implants were measured and analyzed by film dosimeter.</p><p><b>RESULTS</b>For 6 MV X ray, the maximum interface dose increments of titanium plate, titanium intramedullary pin and stainless steel plate were 12.3%, 15.4% and 20.3%. As the radiation energy was increased from 6 MV to 15MV, the maximum interface dose increment of the titanium plate rose from 12.3% to 15.1%, the maximum interface dose increment of the steel plate rose from 20.3% to 30.8%.</p><p><b>CONCLUSIONS</b>Metal implants with different materials have obvious impact on radiation dose distribution. With the increase of the metal atomic number and energy of radiation, the degree of elevated dose also increases. These results suggest that correction of dose distribution is required for radiotherapy of patients with metal implants.</p>
Subject(s)
Metals , Prostheses and Implants , Radiotherapy DosageABSTRACT
Objective:To analyze and compare the results and precision of three different methods to measure the surface dose of Intra-operative radiotherapy,and conclude some experience of clinical application in Intra- operative radiotherapy.Methods:The study compared the results of measurement surface dose in phantom through three ways:cylindrical ionization chamber with 3D water scanner,plane-parallel ionization chamber,and MOSFET detector.Results:the measurement results of plane-parallel-chamber and MOSFET detector have a better consistency,and the maximum deviation is -1.13%.The method with cylindrical ionization chamber and 3D water scanner has larger deviation compare to the other two methods,the deviation range from-5.55%to 4.55%.Conclusion:The methods of plane-parallel chamber and MOSFET detector to measure the surface dose of Intra-operative radiotherapy can obtain accurate results.
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The similarity and difference between stationary and mobile electronic linear accelerators in intra-operative radiation therapy are introduced. The contents and methods of quality assurance for stationary and mobile electronic linear accelerators and the key points to deliver intra-operative radiation therapy are described.