ABSTRACT
Objective@#To explore the possibility that the neck extension in chest CT scanning would make thyroid move upward and reduce thyroid radiation exposure.@*Methods@#The images of 1 994 patients who underwent chest CT examination in Beijing Chaoyang Hospital from March to June in 2017 were compared and analyzed retrospectively. According to different cervical positions, patients were divided into extension group and routine group with 997 cases in each group. In the extension group, the head and neck bended back to the maxillary top position while in the regular group with normal position. The length of thyroid glands exposed to the scanning range and the number of cases of all glands moved out of the scanning range were observed with the first rib head as the baseline counting mark. The differences in exposed length of thyroid gland in primary radiation area between the two groups were compared.@*Results@#The length of exposed thyroid gland by primary radiation in the extension group (4.69±5.68) mm was significantly shorter (U=91 073.5, P<0.05) than that in the routine group (17.16±6.68) mm. In addition, the number of thyroid glands out of scanning range completely in the extension group (n=519, with ratio of 52.1%) was significantly more (U=594.8, P<0.05) than those in the routine group (n=32, with ratio of 3.2%).@*Conclusions@#During chest CT scan, the length of thyroid gland in the scanning field can be shortened with neck backbend position and the radioation protection for thyroid gland can be effectively improved.
ABSTRACT
Objective To explore the possibility that the neck extension in chest CT scanning would make thyroid move upward and reduce thyroid radiation exposure.Methods The images of 1 994 patients who underwent chest CT examination in Beijing Chaoyang Hospital from March to June in 2017 were compared and analyzed retrospectively.According to different cervical positions,patients were divided into extension group and routine group with 997 cases in each group.In the extension group,the head and neck bended back to the maxillary top position while in the regular group with normal position.The length of thyroid glands exposed to the scanning range and the number of cases of all glands moved out of the scanning range were observed with the first rib head as the baseline counting mark.The differences in exposed length of thyroid gland in primary radiation area between the two groups were compared.Results The length of exposed thyroid gland by primary radiation in the extension group (4.69± 5.68) mm was significantly shorter (U=91 073.5,P＜0.05) than that in the routine group (17.16±6.68) mm.In addition,the number of thyroid glands out of scanning range completely in the extension group (n =519,with ratio of 52.1％) was significantly more (U=594.8,P＜0.05) than those in the routine group (n=32,with ratio of 3.2％).Conclusions During chest CT scan,the length of thyroid gland in the scanning field can be shortened with neck backbend position and the radioation protection for thyroid gland can be effectively improved.
ABSTRACT
PMV (Predicted Mean Vote) is a widely used index for evaluating the thermal environment. However, few studies have been conducted to take physiological values directly as evaluating indices. This paper assumes a linear relation between body temperature and both sweating rate and heat produced by shivering, and introduces the linear relation into the human heat balance equation to revise the classic PMV. And the assumption of linear relation is subsequently proved. The revised PMV possesses the same characteristic of dependent heat load as that of the classic one, and moreover it is convenient to be calculated.
ABSTRACT
AIM: By studying the ultrastructure of organs (hearts, brains, lungs, livers, kidneys) and vascular endothelial cells, and changes of physiological and biochemical indexes with multiple organ dysfunction syndrome in the elderly rats, their signification and their developing rules were analyzed. METHODS: Wistar rats(Half of Wister rats were three-month-old and another half of twenty-month-old) were anaesthetized and dealt with cecal ligation puncture (CLP) operation. They were defined as MODSE group and MODSY group, respectively. They were perfused through all vascular circulation by 1% glutaric dialdehyde. These slices were observed under transmission electron microscopy. RESULTS: Physiological and biochemical indexes at 24 huor in elder rats were shown significant difference compared with the younger rats ( P