Objective To study the calculational method for the radiotherapy facilities of the medical linear accelerator' s useful beam towars its maze.Methods The shielding calculation was made under the relevant national standards for a radiotherapy treatment room and compared with the test results.Results The dose rates at the maze entrance as calculated and measured were 89 and 86 μSv/h inside the maze door,as well as 5.7 and 6.2 μSv/h outside the maze door,respectively.The calculated results were consistent with measured results.Conclusions By comparison of calculated results with measured results,the accuracy of the theoretical calculation method could be verified.

Clinical and imaging data of 11 patients with dysembryoplastic neuroepithelial tumors (DNET) and 15 patients with low-grade glioma (LGG) admitted in Northern Jiangsu People's Hospital were analyzed retrospectively.Routine MRI scan,diffusion weighted imaging (DWI) and enhanced scan were performed.The workstation automatically generated apparent diffusion coefficient (ADC) maps and then to obtain ADC values of the tumor parenchymal area and the contralateral normal reference area.Relative tumor/reference ADC values (rADC) were also calculated.The ADC values of parenchymal regions of tumor and contralateral normal reference areas and the rADC between DNET and LGG were compared.There was significant difference in age distribution between the two groups [(16.6± 13.1) vs.(43.0± 19.2) years,t=3.938,P＜0.01].Six out of 11 DNET cases and none of 15 LGG cases were cuneiform or fan-shaped (P＜0.01);5/11 DNET and 0/15 LGG showed circular high signal in fluid attenuated inversion recovery-T2 weighted imaging (T2FLAIR) sequence (P＜0.01),while there no significant differences in intracapsular segmentation,peritumor edema and mass effect,enhancement,and skull compression between two groups (all P＞0.05).The ADC values of tumor parenchymal regions in both groups were significantly higher than those in contralateral reference regions (both P＜0.01),the rADC of DNET was significantly higher than that of LGG (P＜0.01).It is difficult to identify DNET and LGG by conventional image morphology,however the rADC value of DNET in DWI is significantly higher than that of LGG,and can provide important reference for differential diagnosis between them.

Infectious bone defect is bone defect with infection or as a result of treatment of bone infection. It requires surgical intervention, and the treatment processes are complex and long, which include bone infection control,bone defect repair and even complex soft tissue reconstructions in some cases. Failure to achieve the goals in any step may lead to the failure of the overall treatment. Therefore, infectious bone defect has been a worldwide challenge in the field of orthopedics. Conventionally, sequestrectomy, bone grafting, bone transport, and systemic/local antibiotic treatment are standard therapies. Radical debridement remains one of the cornerstones for the management of bone infection. However, the scale of debridement and the timing and method of bone defect reconstruction remain controversial. With the clinical application of induced membrane technique, effective infection control and rapid bone reconstruction have been achieved in the management of infectious bone defect. The induced membrane technique has attracted more interests and attention, but the lack of understanding the basic principles of infection control and technical details may hamper the clinical outcomes of induced membrane technique and complications can possibly occur. Therefore, the Chinese Orthopedic Association organized domestic orthopedic experts to formulate An evidence-based clinical guideline for the treatment of infectious bone defect with induced membrane technique ( version 2023) according to the evidence-based method and put forward recommendations on infectious bone defect from the aspects of precise diagnosis, preoperative evaluation, operation procedure, postoperative management and rehabilitation, so as to provide useful references for the treatment of infectious bone defect with induced membrane technique.