Objective:To assess the consistency between displayed doses and actual doses of the computed tomography(CT)equipment of different manufactories and types through compares the actual measured dose and the displayed dose in CT examination on head of children,so as to provide references for rapid estimation and scientific assessment for the dose in CT examination on head of children.Methods:The CT equipment of two kinds of commonly used brands were selected,which included Brand A(imported equipment,16-slice and 64-slice)and Brand B(domestic equipment,16-slice and 32-slice).A pediatric head phantom was used to conduct scan according to pre-set scan protocol for children at different ages.A ionization chamber that like a pen was adopted to measure CT dose index(CTDI)values of scanning the head of children under various scan parameters,which were compared with the displayed values in equipment.Results:For 16-slices CT of Brand A,the ratio range of actually measured dose to displayed dose was between 1.08 and 1.10.For the 64-slices CT of Brand A,that was between 1.11 and 1.17.For the 16-slices CT of Brand B,that was between 1.00 to 1.04.For the 32-slices CT of Brand B,that was between 1.12 to 1.21.All ratios were slightly higher than 1,but were within a relatively concentrated range.Under the products of different tube voltages(kV)and tube current-time(mAs),the volatility of ratio range of actually measured dose to displayed dose of different ages was less than 5%,which indicated the deviations were stable,and the influence of parameters was less.Conclusion:In CT examinations on head of children,the consistency of the ratio value between actually measured value and displayed value is higher under the acquiescent scan conditions of the scan protocol for head of children at different ages,which can conduct rapidly dose estimation as a certain conversion coefficient.

Objective:To assess the consistency between displayed doses and actual doses of the computed tomography(CT)equipment of different manufactories and types through compares the actual measured dose and the displayed dose in CT examination on head of children,so as to provide references for rapid estimation and scientific assessment for the dose in CT examination on head of children.Methods:The CT equipment of two kinds of commonly used brands were selected,which included Brand A(imported equipment,16-slice and 64-slice)and Brand B(domestic equipment,16-slice and 32-slice).A pediatric head phantom was used to conduct scan according to pre-set scan protocol for children at different ages.A ionization chamber that like a pen was adopted to measure CT dose index(CTDI)values of scanning the head of children under various scan parameters,which were compared with the displayed values in equipment.Results:For 16-slices CT of Brand A,the ratio range of actually measured dose to displayed dose was between 1.08 and 1.10.For the 64-slices CT of Brand A,that was between 1.11 and 1.17.For the 16-slices CT of Brand B,that was between 1.00 to 1.04.For the 32-slices CT of Brand B,that was between 1.12 to 1.21.All ratios were slightly higher than 1,but were within a relatively concentrated range.Under the products of different tube voltages(kV)and tube current-time(mAs),the volatility of ratio range of actually measured dose to displayed dose of different ages was less than 5%,which indicated the deviations were stable,and the influence of parameters was less.Conclusion:In CT examinations on head of children,the consistency of the ratio value between actually measured value and displayed value is higher under the acquiescent scan conditions of the scan protocol for head of children at different ages,which can conduct rapidly dose estimation as a certain conversion coefficient.

Objective　: To verify the feasibility of using a homemade lung phantom for quality control of Cyberknife by comparing the measurement results of the homemade lung phantom and CIRS dynamic phantom in E2E testing of Cyberknife lung tracking.  Methods　 : The patient treatment process was simulated, including CT positioning, plan design, irra- diation implementation, film scanning, and analysis using the homemade phantom and CIRS phantom. The two phantoms were measured five times using MLC under the S7 generation Cyberknife and five times using Iris under the M6 generation Cyberknife. The differences in measurement results between the two phantoms were analyzed using independent sample t-test. Results　: For the S7 generation Cyberknife, the statistical analysis of differences between the two phantoms in the detection values on the X-axis, Y-axis, Z-axis, and total deviation showed P values of 0.236, 0.175, 0.289, and 0.668, respect- ively. For the M6 generation Cyberknife, the statistical analysis showed P values of 0.880, 0.891, 0.573, and 0.433, respect- ively. The P values were all > 0.05. Therefore, there were no statistically significant differences in the detection results between the homemade lung phantom and the CIRS phantom under the S7 and M6 generation Cyberknife. The total deviation values were <1.5 mm. Conclusion　 The homemade lung phantom and CIRS phantom have consistent measurement results in the E2E testing of Cyberknife lung tracking and meet the requirements of Report of AAPM TG-135 and WS 667- 2019 standard. Therefore, the homemade lung phantom is feasible for clinical quality control of Cyberknife.

Objective To establish testing and evaluation methods for radiation shielding performance of a self-shielded radiotherapy system by measuring the radiation levels around the self-shielded head and neck radiotherapy system. Methods A total of 14 monitoring points were selected outside the restricted zone of the system. Under radiation conditions from five different fixed directions, an ion chamber survey meter was used to measure and identify the maximum ambient dose equivalent rate at the 14 points. The time-averaged dose rate was then calculated based on the workload. In accordance with relevant radiation protection standards, an instantaneous dose rate of 10 μSv/h and a time-averaged dose rate of 2.0 μSv/h were proposed as the criteria for shielding protection evaluation. Results Based on the ambient dose equivalent rates at the 14 monitoring points outside the restricted zone, the maximum instantaneous dose rate outside the restricted zone was 7.4 μSv/h. With a workload of 15 patients per day, the maximum time-averaged dose rate was 1.0 μSv/h, which can be used as the criteria for shielding protection evaluation. Conclusion By considering both instantaneous dose rate and time-averaged dose rate, a comprehensive safety assessment of the radiation shielding performance of a self-shielded radiotherapy system can be conducted.

Objective To explore the feasibility of quartz glass for radiotherapy dosimetry through the experimental study of the thermoluminescence characteristics of synthetic quartz glass. Methods The thermoluminescence glow curves of quartz glass under different annealing conditions were analyzed, the thermoluminescence characteristics of quartz glass were studied, and the measurement parameters were optimized. Using the Co-60 reference radiation field in the National Secondary Standard Dosimetry Laboratory, the quartz glass samples under different annealing conditions were irradiated following the dose levels of radiotherapy, i.e., 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 Gy, respectively. According to the relationship between the absorbed dose of quartz glass and the relative thermoluminescence signal intensity, the linearity and dispersion of the dose response of quartz glass were obtained, and the feasibility of quartz glass for radiotherapy dosimetry was analyzed. Results The linear correlation coefficient of dose response of quartz glass under annealing condition of 430℃ for 10 min was 0.9984, and the dose response dispersion was 0.97% at the absorbed dose of 2 Gy. The linear correlation coefficient of dose response of quartz glass under annealing condition of 600℃ for 1 h was 0.9911, and the dose response dispersion was 1.4% at the absorbed dose of 2 Gy. Conclusion Preliminary results suggest that quartz glass with annealing condition of 430℃ for 10 min has the potential to be used for radiotherapy dosimetry.

Objective:To evaluate the radiation shielding performance for a novel self-shielded ZAP-X radiotherapy system used for intra-cranial and neck treatments. The present evaluation was performed according to the relevant Chinese national standards and the clinical placement of the radiotherapy system in an unshielded treatment room.Methods:The radiation source of the ZAP-X was a 3 MV linear accelerator. A total of 33 detection sites were selected surrounding the self-shielded system at 1.3, 2.3 and 3.3 m away from the periphery of the equipment. The maximum ambient dose equivalent rate in each irradiation condition was measured accordingly. A commonly used clinical treatment plan was selected to simulate the treatment process. During the delivery of this treatment plan, the cumulative doses of these 33 sites were measured, separately. The applicable current radiation protection standard for radiotherapy in China was chosen to evaluate the radiation shielding performance of the system.Results:According to the measurement result of the ambient dose equivalent rates along the aforementioned perimeter lines, a suggestion was put forward to redefine the existing 1 m controlled area by determining the distance at which the instantaneous dose rate of 10 μSv/h will not be exceeded. This is to meet the requirements of the Chinese standard GBZ 121-2020.Conclusions:According to the existing Chinese national radiation protection standards, the self-shielded radiotherapy system in the unshielded treatment room has the clinical applicability in China. But for such a novel self-shielded system, the corresponding performance testing and radiation protection standards shall be formulated.

ObjectiveTo investigate the intestinal absorption characteristics of multi-index components in Danggui Buxuetang with drug absorption simulating system （DASS） established by everted intestinal sac model. MethodThe intestinal absorption solution at different time points after administration of Danggui Buxuetang was collected and detected by high performance liquid chromatography （HPLC）， acetonitrile （A）-0.2% glacial acetic acid solution （B） was used as the mobile phase for gradient elution （0-16 min， 15%-23%A； 16-20 min， 23%-28%A； 20-25 min， 28%-30%A； 25-30 min， 30%A； 30-35 min， 30%-65%A； 35-45 min， 65%-95%A）， the detection wavelength was 302 nm. HPLC fingerprint of intestinal absorption solution was established and the common peak was calibrated， and the relative cumulative absorption rate of each index component was calculated. The relative cumulative absorption curves of components were fitted with various mathematical models by DDSolver 1.0 to explore the absorption law of different components. ResultThe absorption process of C2 （calycosin-7-glucoside） and C6 in Danggui Buxuetang was in line with zero-order equation， C9 was best fitted by Weibull equation， and the remaining 7 components were in line with Makoid-Banakar equation. C1 with C2， C3， C5， C7 and C10， C2 with C5 and C7， C3 with C4， C5， C7 and C10， C4 with C6 and C10， C5 with C7， C6 with C10， C7 with C10， C8 with C9 were absorbed simultaneously during the absorption process. With the prolongation of time， the overall cumulative absorption rate of Danggui Buxuetang increased. At 120 min， the overall cumulative absorption rate of Danggui Buxuetang exceeded 38%， and reached 49.14% at 180 min. ConclusionTen ingredients in Danggui Buxuetang are absorbed in the jejunum， but absorption law of various components is different， which shows that the intestinal absorption of compound preparations of traditional Chinese medicine （TCM） has multiple characteristics. Intestinal absorption study of TCM compound preparations with chemical composition as the index can reveal some of its absorption law， but it is not complete.

Objective: To discuss the feasibility of applying home-made auto quality assurance (AQA) phantom in Cyberknife AQA test. Methods: The same treatment plan for AQA test was designed in the Cyberknife treatment planning system. The AQA tests were performed under the same conditions using the home-made AQA phantom and the AQA phantom in the fourth-generation (G4) Cyberknife mode and the fifth-generation (VSI) Cyberknife mode, respectively, and each measurement was repeated five times to analyze and compare the differences in test results between the two phantoms. Results: The total deviations of the home-made AQA phantom and the AQA phantom in the AQA test under the G4 Cy- berknife mode were (0.28 ± 0.12) mm and (0.28 ± 0.15) mm, respectively (P > 0.05); the test results under the VSI Cy- berknife mode were (0.46 ± 0.19) mm and (0.50 ± 0.07) mm, respectively (P > 0.05); the total deviations of all test results were smaller than 1.0 mm, which met the requirements of WS 667—2019 Specification for Testing of Quality Control in Ro- botic Arm Radiotherapy Device. Conclusion The test results of the home-made AQA phantom and the AQA phantom are consistent in the AQA test, and the home-made AQA phantom can be used for Cyberknife quality control.

Congenital hydrocephalus is a major neurological disorder with high rates of morbidity and mortality; however, the underlying cellular and molecular mechanisms remain largely unknown. Reproducible animal models mirroring both embryonic and postnatal hydrocephalus are also limited. Here, we describe a new mouse model of congenital hydrocephalus through knockout of β-catenin in Nkx2.1-expressing regional neural progenitors. Progressive ventriculomegaly and an enlarged brain were consistently observed in knockout mice from embryonic day 12.5 through to adulthood. Transcriptome profiling revealed severe dysfunctions in progenitor maintenance in the ventricular zone and therefore in cilium biogenesis after β-catenin knockout. Histological analyses also revealed an aberrant neuronal layout in both the ventral and dorsal telencephalon in hydrocephalic mice at both embryonic and postnatal stages. Thus, knockout of β-catenin in regional neural progenitors leads to congenital hydrocephalus and provides a reproducible animal model for studying pathological changes and developing therapeutic interventions for this devastating disease.
Animals ; Disease Models, Animal ; Hydrocephalus/genetics* ; Mice ; Mice, Knockout ; Neurons ; beta Catenin/genetics*

BACKGROUND:With more and more elderly patients suffering lumbar degenerative disease undergoing internal fixation, infection after spinal internal fixation is a common complication in orthopedic surgeries, but its treatment strategy remains controversial.OBJECTIVE: To explore the curative efficacy of incision infection after internal fixation in the elderly with lumbar degenerative disease.METHODS: 197 patients with lumbar degenerative disease undergoing internal fixation and followed up for more than 2 years admitted in Department of Orthopedics, Beijing Shijitan Hospital Affiliated to Capital Medical University from January 2012 to January 2015, were analyzed retrospectively. The follow-up time was 2-4.9 years. There were 97 cases of lumbar stenosis, 29 cases of lumbar disc herniation, 33 cases of lumbar spondylolisthesis, 17 cases of degenerative scoliosis and 21 cases of lumbar compression fractures.RESULTS AND CONCLUSION: (1) Eleven patients experienced incision infection, including ten acute, and one delayed infection. (2) Among acute infected cases, three were superficial infection in three cases and seven had deep infection,who characterized as exudation (10/10), local pain (8/10) and fever (9/10). Acute infected cases received bacterial culture, drug sensitive test, antibiotic therapy, and debridement of the infected wound, and leaving all internal fixators in situ in all but one case. (3) For delayed infection, one patient had local pain, incision exudation, and intermittent fever,and then the internal fixators were removed. (4) Pseudarthrosis was not founded during 2-year follow-up in all patients.(5) These results suggest that for the elderly patients suffering lumbar degenerative disease with infection after internal fixation, intravenous antibiotics, debridement plus drainage are recommended, but without internal fixator removal, and repetitive debridement and drainage is a rational choice if necessary.