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Objective To explore the influencing factors of目的 分析PET/CT显像中影响棕色脂肪(BAT)

To characterize the brown adipose tissue (BAT) uptake of 18F-FDG on positron emission tomography (PET)/computed tomography (CT) imaging.We retrospectively analyzed the clinical data of 1 080 patients who received all whole-body PET/CT studies in Peking Union Medica College Hospital from July 2008 to February 2009.Forty-one patients (3.8%) were identified to be with BAT uptake, especially during cold seasons. BAT uptake was mostly observed at the neck regions symmetrically (n = 39), and was also seen at paravertebral junctions (n = 30), perinephric regions (n = 21), and mediastinum (n = 10). Patients with BAT uptake had significantly lower male/female ratio (P = 0.0030), younger age (P = 0.0001), and less body mass index (BMI) (P = 0.0415). Three patients with high BAT uptake underwent repeat PET/CT scans 3-7 days later. By keeping warm and full relaxation, BAT uptake disappeared in 2 cases and dramatically decreased in the other case.BAT uptake commonly occurs during cold seasons in Beijing, especially in young females with low BMI. It usually has specific patterns, and can be avoided or remarkably reduced by asking the patients keep warm and full relaxation a few days before the scanning.

In one software system, the software’s reliability and safety are ultimately determined by the program operating states, which will be changed as the exterior and interior environment changing. in this paper, according with the environmental factor which lead to the changing of program states, the definition of the deviation loss caused by the changing of program states is presented, and in some conditions is proposed ? the formal method is used to describe the transition rules between the software reliability and safety. Finally, the formal proofs of these rules are given.

In this paper, the transition between the software reliability and safety of a software system is studied. A transition occurs when the program states are changed and different environmental factors are chosen. By using the formal method, the transition rules are established and proved in this paper.

A new method based on sequential Monte Carlo algorithm is proposed for tracking multi-target and data association in non-linear system. The algorithm partitions the problem of multi-target tracking into two problems: single target tracking and data association. Single target tracking is implemented by using UKF and data association by using sequential Monte Carlo algorithm. Since Particle Filter has advantages in non-linear non-Gauss system, the proposed method performs well in the experiment.

To observe the characteristics of the physiological uptake of uterus and ovaries on 18F-fluorodeoxyglucose positron emission tomography (FDG PET).A total of 288 PET examinations performed in 247 women (164 with malignancies, 44 with benign diseases, and 39 without remarkable abnormality) were included for analysis, and clinical follow-ups were applied for at least 10 months to exclude pelvic diseases. The menstrual statuses, menstrual cycles, and related pelvic examinations with other modalities were inquired before each PET examination. PET scanning was performed from pelvis to neck with a Siemens ECAT EXACT HR + system. The uptake levels of uterus and ovaries were set as intense, moderate, and mild by comparing to liver uptake.In 116 patients (131 examinations ) with regular menstruation, the endometrial uptake, usually in inverted cone shape surrounded by relatively low-uptake uterine wall, was observed with two peaks in the early menstrual flow phase and in the mid-cycle respectively; the ovarian uptake was more prominent in the mid-cycle, with the foci of uptake in ovoidal shape and located at the left and/or right side superior-posterior to the bladder. From the early menstrual flow phase to the late secretory phase of the menstrual cycles, the probabilities of mild uptake in both endometrium and ovaries were 7%, 86%, 80%, 58%, 20%, 40%, 64%, and 59%, respectively, indicating that the late menstrual flow phase and the early proliferative phase had the least probability of intense or moderate uptake. No intense uptake was observed in the 17 patients (19 examinations) presenting remarkably irregular menstrual cycle, 112 patients (136 studies) in menopause for 3 months to 39 years, and 2 patients without menstruation yet. Only one patient within 1 year of menopause and a 14-year-old girl expected to start menstruation showed mild to moderate uptake in the endometrium.The physiological endometrial and ovarian uptakes have specific shapes and positions on 18F-FDG PET images, which correlates well with the menstrual phases.