Objective To explore the effect of different additional filters on radiation dose and image quality in digital mammography.Methods Hologic company's Selenia digital mammography machine and the post-processing workstations and 5 M high resolution medical monitor were used in this study.Mammography phantoms with the thickness from 1.6 cm to 8.6 cm were used to simulate human breast tissue.The same exposure conditions,pressure,compression thickness,the anode were employed with the additional filters of Mo and Rh under the automatic and manual exposure mode.The image kV,mAs,pressure,filter,average glandular dose (AGD),entrance surface dose (ESD),signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR) and image score according to ACR criteria were recorded for the two additional filters.Paired sample t test was performed to compare the indices of Mo and Rh groups by using SPSS 17.0.Results AGD and ESD of Rh and Mo group were both higher with the increase of the thickness of all the phantoms.AGD,ESD and their increased value of Rh filter(1.484 ± 1.041,7.969 ± 7.633,0.423 ± 0.190 and 3.057 ± 2.139) were lower than those of Mo filter(1.915 ± 1.301,12.516 ± 11.632,0.539 ±0.246 and 4.731 ± 3.294),in all the phantoms with different thickness (t values were 4.614,3.209,3.396 and 3.605,P ＜0.05).SNR,CNR,and image score of Rh and Mo group both decreased with the increase of the thickness of all the phantoms.There were no statistical difference (P ＞ 0.05).Conclusions Compared with Mo filter,Rh filter could reduce the radiation dose,and this advantage is more obvious in the thicker phantom when the same image quality is required.

OBJECTIVETo investigate the current status of smoking and passive smoking among Chinese females to provide evidence for related strategy development.

METHODSData from 32 720 women aged 45-65 years old who participated in the 2008 to 2010 Chinese Multi-center Women Breast Cancer Screening Project, were used to analyze the prevalence rates of smoking/heavy smoking, daily smoking, smoking cessation, successful smoking cessation, passive smoking, etc.

RESULTSA total of 913 females, accounted for 2.8% of all the women in the study, had reported the history of smoking. There were significant differences seen regarding the prevalence rates of smoking in different regions (Beijing, 2.8%; Tianjin, 5.9%; Nanchang, 1.7%; Feicheng, 0.9%; Shenyang, 1.8%). The prevalence rates of current smoking, daily smoking, and heavy smoking were 1.8%, 1.0% and 0.2%, respectively. The prevalence rates of smoking and current smoking increased with age but not the prevalence rates of daily smoking and heavy smoking. Among the smokers, the median initiation age of smoking, the median daily cigarette per day, and median year of smoking were 30 years old, 10 cigarette, and 16 years, respectively. And the prevalence rates of smoking cessation and successful smoking cessation were 19.1% and 8.2%. The prevalence rate of passive smoking was 45.7% (12 730/27 874). After combing the number of smokers and the number of passive smokers, the total exposure rate to tobacco was 41.8% (13 670/32 720).

CONCLUSIONThere was a relatively low level of smoking among Chinese females, so as the rate of smoking cessation. However, passive smoking presented a relatively high level among Chinese females.

Aged ; China ; epidemiology ; Female ; Humans ; Middle Aged ; Prevalence ; Smoking ; epidemiology ; Tobacco Smoke Pollution ; statistics & numerical data