Objective To investigate the effects of high glucose and lysophosphatidylcholine (LPC) on the immune function of in vitro cultured macrophages during Nocardia farcinica infection. Meth-ods RAW264.7 macrophages were cultured in vitro under different conditions as follows: routine culture (control group),50 mmol/L glucose (high glucose group),10 mg/L LPC(LPC groupⅠ),25 mg/L LPC (LPC groupⅡ) and 50 mmol/L glucose+25 mg/L LPC(high glucose and LPC group). The activity of mac-rophages in each group was tested after 6,12,24 and 36 h of culture. After 24 h of culture, macrophages were collected from every group and co-cultured with Nocardia farcinica. Dynamic phagocytosis rates were detected at 1,2,3,4,5 and 6 h after co-culture. Toxic effects of Nocardia farcinica on macrophages and concentrations of IL-10 and TNF-α were measured at 1,3 and 6 h after co-culture. Results Macrophages in all four experimental groups showed decreased activity as compared with those in the control group (P<0.01). Phagocytosis of Nocardia farcinica by macrophages was also reduced by high glucose and LPC. Phagocytosis rates of high glucose group and LPC groupⅡ at 1 and 2 h,LPC groupⅠat 1,2 and 3 h,and high glucose and LPC group at 1,2,3 and 4 h after co-culture were significantly lower than that of the con-trol group (P<0.05 or P<0.01). Compared with the control group, significantly reduced toxic effects on macrophages caused by Nocardia farcinica was observed in the experimental groups (P<0.05 or P<0.01). Compared with the control group,LPC groupsⅠand Ⅱ and high glucose and LPC group had decreased se-cretion of IL-10 at 3 h,and high glucose group and LPC groupⅠhad decreased secretion of TNF-α at 1 h(P<0.05). Conclusion Culture macrophages under the conditions of high glucose and LPC would reduce their activity and impair their ability to phagocytose Nocardia farcinica. Moreover, high glucose and LPC might have impacts on the toxic effects of Nocardia farcinica on macrophages and the secretion of IL-10 and TNF-α.

Objective To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) with flattening filter(FF) and flattening filter-free(FFF) modes in hippocampal avoidance whole brain radiotherapy. Methods We included 15 patients with hippocampal-sparing whole brain radiotherapy, and designed two radiotherapy plans of FF-VMAT and FFF-VMAT for each patient. On the premise of meeting clinical dose requirements, the two plans’ dosimetry, total number of monitor units, and beam-on time were compared. Results There were no significant differences in the target coverage, conformity index, and dose gradient of the FF-VMAT and FFF-VMAT plans (P > 0.05). The D_max, D_100%, and D_mean to the hippocampal tissue were significantly lower with FFF-VMAT [(15.13 ± 0.38) Gy, (7.12 ± 0.34) Gy, and (9.76 ± 0.43) Gy, respectively)] than with FF-VMAT (16.46 ± 0.56) Gy, (7.72 ± 0.28) Gy, and (10.54 ± 0.48) Gy, respectively)] (P < 0.05). The D_max to the left and right lenses and the D_mean to the left and right eyeballs with FFF-VMAT were (7.26 ± 0.43) Gy, (6.29 ± 1.13) Gy, (11.01 ± 0.94) Gy, and (9.78 ± 1.13) Gy, respectively, which were significantly lower than FF-VMAT’s corresponding doses of (8.09 ± 0.66) Gy, (7.80 ± 0.74) Gy, (11.38 ± 1.09) Gy, and (11.05 ± 0.90) Gy, respectively (P < 0.05). The doses to other organs at risk including the optic nerve and optic chiasm were all controlled within the safe dosage ranges, with no significant differences between the two plans (P > 0.05). The FFF-VMAT plan had a significantly greater number of monitor units and a significantly shorter beam-on time than the FF-VMAT plan (P < 0.05). Conclusion Both FF-VMAT and FFF-VMAT can meet the clinical requirements, with FFF-VMAT having better hippocampus and lens protection, shorter beam-on time, and higher treatment efficiency.

Objective To propose a method for correcting the attenuation of positron emission tomography (PET) data in PET/magnetic resonance (MR) based on transmission scan, and to improve image quality, diagnostic accuracy, and lesion location accuracy. Methods In this study, the head phantom in the national standard GB/T 18988.1—2013 was used as the experimental model. The head phantom contained three 50 mm diameter cylindrical inserts filled with air, water, and solid teflon. The attenuation correction coefficients were calculated and analyzed based on transmission scan. Results With slice = 33 and theta = 0, the attenuation correction coefficient was the largest (about 7.5) when the coincidence line passed through the axis of the phantom. The spatial distribution of the attenuation correction coefficients clearly showed the positions of air insert and teflon insert, indicating that the attenuation correction coefficients calculated from transmission scan data were accurate. In the clinical verification experiment, the attenuation correction method based on transmission scan significantly improved the image quality and showed efficient attenuation correction. Conclusion This paper studied the attenuation correction method for PET data in PET/MR based on transmission scan. This method can improve the image quality. In the future work, the attenuation correction method of PET/MR will be further studied and optimized to facilitate clinical applications.

Objective To propose a method for correcting the attenuation of positron emission tomography (PET) data in PET/magnetic resonance (MR) based on transmission scan, and to improve image quality, diagnostic accuracy, and lesion location accuracy. Methods In this study, the head phantom in the national standard GB/T 18988.1—2013 was used as the experimental model. The head phantom contained three 50 mm diameter cylindrical inserts filled with air, water, and solid teflon. The attenuation correction coefficients were calculated and analyzed based on transmission scan. Results With slice = 33 and theta = 0, the attenuation correction coefficient was the largest (about 7.5) when the coincidence line passed through the axis of the phantom. The spatial distribution of the attenuation correction coefficients clearly showed the positions of air insert and teflon insert, indicating that the attenuation correction coefficients calculated from transmission scan data were accurate. In the clinical verification experiment, the attenuation correction method based on transmission scan significantly improved the image quality and showed efficient attenuation correction. Conclusion This paper studied the attenuation correction method for PET data in PET/MR based on transmission scan. This method can improve the image quality. In the future work, the attenuation correction method of PET/MR will be further studied and optimized to facilitate clinical applications.