10.3969/j.issn.1007-3969.2013.04.011

Objective: To apply GBZ/T298-2017 "Guidelines for occupational health risk assessment of chemicals in the workplace" to conduct an occupational health risk assessment of 2-butoxyethanol exposure in a printing enterprise, in order to protect the laborers' health. Methods: Conducted a worksite survey of occupational health include data collection, site investigation, determination 2-butoxyethanol in workplace air and raw and auxiliary material, determination 2-butoxyacetic acid in urine after shift from May 17 to 24, 2017, using the above results, conducting 2-butoxyethanol occupational health risk assessment. Results: Concentrations of 2-butoxyethanol in the workplace air ranged from 1.2-30.8 mg/m³. Concentrations of 2-butoxyaceticacid in urine ranged from 35.5 mg/L to 563.3 mg/L. The printing shop with the highest concentration of air in the workplace in the enterprise was a medium risk for 2-butoxyethanol occupational health risks, and the binding workshop printer was a low risk for 2-butoxyethanol occupational health risks. The occupational health risk of 2-butoxyethanol in the print shop was medium. Conclusion Occupational health risks of 2-butoxyethanol for companies is medium, which should be included in the evaluation of routine occupational hazards and provide more targeted recommendations based on the action levels.

Objective:To study the impact of the Varian real-time position management (RPM) respiratory gating system on radiotherapy planning dosimetry.Methods:The radiotherapy plans of 40 cases with thoracic or abdominal tumors were retrospectively selected in this study. The motion phantom for quality control was adopted to generate respiratory gating signals, and the 30%-60% stable phase at the end of expiratory was selected as the respiratory gating window. The dose verification for the abovementioned radiotherapy plans was performed using the Portal Dosimetry (PD) system under RPM respiratory gating mode with the Edge accelerator. Afterwards, dose analysis was performed with different γ passing rate criteria and the distribution characteristics of γ values were analyzed. Finally, the verification results between the non-gating mode and the gating mode were compared.Results:Under the respiratory gating mode, the passing rates of all intensity-modulated radiation therapy/volumetric-modulated arc therapy (IMRT/VMAT) plans with or without flattening filters were over 95.5% by γ criteria of (3%, 3 mm) or (3%, 2 mm) and were over 90% by stricter γ criteria of (2%, 2 mm). All plans met the clinical requirements recommended by the American Association of Physicists in Medicine (AAPM). The passing rates of dose verification under non-gating mode were slightly better than those under respiratory gating mode, and the differences between the two modes were statistically significant (3%/3 mm, Z =-1.45; 3%/2 mm, Z =-2.86; 2%/2 mm, Z =-3.70; 1%/1 mm, Z =-4.52; P<0.05). There was no significant difference in the minimum and maximum values of γ and the share of γ > 1.5 of plan verification result under the two modes. However, the average value and standard deviation of the γ were generally smaller under the non-gating mode. Conclusions:The impact of the introduction of RPM respiratory gating technology on dose is clinically acceptable, and the execution of these plans in this gating mode is safe and reliable.