Subjects: Physics >> Nuclear Physics submitted time 2023-11-01
Abstract： Carbon ion radiotherapy is expected to become a workhorse for head and neck tumors radiotherapy due to its inverted depth dose distribution and high relative biological effectiveness, which has the advantages of less damage to normal tissues and low side effects. The accuracy of dose algorithms directly affects the accuracy of clinical irradiation doses, and reducing the dose calculation error of carbon ion radiotherapy could help improve patient’s survival and local control rates. In this paper, the dose distribution of carbon ion radiotherapy for 5 head and neck patients were calculated by the analytic pencil beam algorithm and validated using Monte Carlo method. Three analysis methods were carried out for the calculated and simulated results: (1) Gamma pass rate analysis under multiple evaluation criteria combination (2%/2mm, 3%/2mm, 3%/3mm, 3%/5mm), (2) DVH and reference index analysis, (3) central axis dose curve comparison. The analysis results showed that the average gamma pass rate of the pencil beam algorithm was 90.441% under the evaluation criteria of 3%/2mm, which met the dose calculation requirements of carbon ion radiotherapy for head and neck tumors. The pencil beam algorithm calculated more accurate in the beam transverse direction, and there is a range deviation by which the structure inhomogeneity and cavity exited in the irradiation path. In order to reduce the impact of dose calculation error, a more conservative angle selection to carbon-ion beam treatment of head and neck tumors is recommended. The results herein could be used to guide the design of carbon ion radiotherapy for head and neck tumors based on analytical pencil beam algorithm.
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Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-20 Cooperative journals: 《计算机应用研究》
Abstract： With the global aging population increasing, the daily behavior regulation and care of the old people have become a challenging social problem. In order to deal with the growing demand of society, this paper proposes a method that is driven by data and knowledge, and uses PSL (probabilistic soft logic) and multi-level analysis for modeling the old people's daily activities to solve the problem of nursing activity recognition. Experiments show that the method has higher accuracy than HMM in the event identification and abnormal activity detection, and has faster response speed than the non-hierarchical recognition method.
Subjects: Medicine, Pharmacy >> Preclinical Medicine submitted time 2017-12-07 Cooperative journals: 《南方医科大学学报》
Abstract： Objective To assess the effects of minimal invasive surgery through an incision near the rectus abdominis muscle for treatment of pelvic fractures sustained in earthquake. Methods Nine patients with pelvic fractures during Ludian earthquake (August 3, 2014) were treated with minimal invasive surgery through an incision near the rectus abdominis muscle followed by anterior ring fixation and reconstruction plate or posterior ring fixation with percutaneous sacroiliac lag screws. The operative time, incision length, blood loss volume, and pre- and postoperative pain levels were recorded. The surgical complications such as lateral femoral cutaneous nerve injury and hip adduction incapability were observed. Results The minimal invasive surgery achieved satisfactory clinical effects and allowed convenient operation with better surgical exposure, shorter operative time, less blood loss and pain. The patients showed excellent fracture reduction and stable internal fixation without lateral femoral cutaneous nerve injury or hip adduction incapability. Conclusions The minimal invasive surgery through an incision near the rectus abdominis muscle is suitable for treatment of pelvic fractures with anteriorly interior fixation, especially in rescuing victims in the event of an earthquake where blood supply can be very limited.
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