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1.
Chinese Journal of Radiological Medicine and Protection ; (12): 653-656, 2023.
Article in Chinese | WPRIM | ID: wpr-993139

ABSTRACT

Compared with conventional radiotherapy, FLASH radiotherapy has advantages in protecting normal tissues, while the dose rate is increased by more than 100 times. If the shielding design of the treatment room is carried out according to the existing standard, the thickness and cost of the shielding wall will be significantly increased, or even hardly to meet the requirement of the standards, resultsing in the failure of the application of FLASH radiotherapy. By investigating the domestic and foreign standards and literature, this paper analyzes the challenges brought by FLASH radiotherapy technology to the shielding design of radiotherapy treatment room in China. Dose rate control standards adopted by different countries in the shielding design are emphatically compared as well. In several countries, the average dose rate under the actual treatment conditions was considered in the shielding design. In China, the method of instantaneous dose rate taking acount of occupancy factor is adopted. However, if FLASH radiotherapy technology is applied, the requirement of instantaneous dose rate will be difficult to meet. In order to improve the high dose rate radiotherapy technology such as FLASH radiotherapy, the revision of the existing standards is advised if the authorized limits are not changed. To use the average dose rate limit within a certain period of time for control, or to raise the control standard in the case of flash radiotherapy, are also avaliable.

2.
Chinese Journal of Experimental Traditional Medical Formulae ; (24): 72-81, 2023.
Article in Chinese | WPRIM | ID: wpr-972287

ABSTRACT

ObjectiveTo observe the protective effect and mechanism of Tianhuang formula (THF) against renal injury in hyperuricemia nephropathy (HN) mice through network pharmacology. MethodAll mice were randomly divided into a normal group, a model group, a febuxostat group (5 mg·kg-1), a low-dose THF group (L-THF, 60 mg·kg-1), and a high-dose THF group (H-THF, 120 mg·kg-1). The mice in the normal group were treated with 0.5% sodium carboxymethylcellulose (CMC-Na) by gavage daily. The HN model was induced by oral administration of 500 mg·kg-1 hypoxanthine and intraperitoneal injection of 200 mg·kg-1 oteracil potassium in mice except for those in the blank group. The mice in the groups with drug intervention were treated with corresponding drugs by gavage for three weeks. The levels of serum uric acid, creatinine, urea nitrogen, and 24-h albuminuria were measured. The renal injury was observed by hematoxylin-eosin (HE) staining and PAS staining, and renal fibrosis was observed by Sirius red staining. The effects and molecular mechanism of THF in HN mice were analyzed by Western blot, network pharmacology, and molecular docking. ResultBiochemical results indicated that compared with model group, BUN and 24 h urinary protein levels were significantly decreased in L-THF group (P<0.05), SUA and SCr levels were significantly decreased (P<0.01), and SUA, BUN, SCr and 24 h urinary protein levels in H-THF group were significantly decreased (P<0.01). The results of pathological staining showed that the kidney injury and interstitial fibrosis were improved in different doses of THF groups (P<0.05). Western blot results showed that the Nod-like receptor heat protein domain associated protein 3 (NLRP3) inflammatorome, interleukin-1β (IL-1β), fibronectin (FN), uric acid transporter 1 (URAT1), phosphorylated p65 (p-p65) and phosphorylated nuclear transcription factor (NF) -κB were inhibited in the H-THF group The expression of protein-producing α (p-IκBα) was reduced to the normal level (P<0.01), but the expression of IL-1β, URAT1 and p-IκBα in HN mice was not affected in the L-THF group. ConclusionTHF ameliorates renal inflammation and fibrosis by inhibiting the activation of NF-κB and NLRP3 inflammasomes to alleviate HN

3.
Chinese Journal of Medical Education Research ; (12): 1183-1187, 2023.
Article in Chinese | WPRIM | ID: wpr-991497

ABSTRACT

Objective:To investigate the value of mind map combined with blended teaching in improving the teaching quality of medicinal botany. Methods:A total of 102 students studying the course of medicinal botany were enrolled as subjects. The 51 students in the class of 2020 were enrolled as control group and received conventional teaching, and the 51 students in the class of 2021 were enrolled as observation group and received mind map combined with blended teaching. The two groups were assessed in terms of examination scores, critical thinking ability scores, self-learning ability scores, and student feedback on teaching quality. SPSS 22.0 was used for the t-test and the chi-square test. Results:Compared with the control group, the observation group had significantly higher examination scores ( t=3.01 and 3.14, P=0.003 and 0.002). After practice, both groups had increases in the scores of critical thinking ability and self-learning ability, and the observation group had significantly higher scores than the control group ( t=11.22 and 2.69, P<0.001 and P=0.008). Compared with the control group, the observation group had a better student feedback on teaching quality than the control group ( t=6.79, 7.83, 7.26, 7.43, and 8.54, P=0.009, 0.005, 0.007, 0.006, and 0.003). Conclusion:The combination of mind map and blended teaching can improve the examination scores of students and their critical thinking ability and self-learning ability, and students believe that this teaching model can help to improve teaching quality.

4.
Chinese Journal of Organ Transplantation ; (12): 611-616, 2022.
Article in Chinese | WPRIM | ID: wpr-994612

ABSTRACT

Objective:To evaluate the efficacy and safety of upfront autologous hematopoietic stem cell transplantation(auto-HSCT)as a consolidation therapy of progressive nasal type extranodal NK/T-cell lymphoma, (ENKL).Methods:From January 2012 to June 2021, clinical data were retrospectively reviewed for 28 patients with advanced-stage ENKL on chemotherapy of asparaginase-containing regimen followed by upfront auto-HSCT as a consolidation therapy.The median age at transplantation was 34.5(14-61)years.There were 19 males and 9 females.Clinical types were nasal(n=22)and non-nasal(n=6). Clinical stages were Ann Arbor III(n=15)and IV(n=13). Clinical risks were intermediate(n=8)and high(n=20)according to the Prognostic Index for Natural-Killer cell lymphoma-Epstein-Barr virus(PINK-E).Results:Hematopoietic reconstruction was performed.Median time of neutrophil engraftment was 10(8-17)days and 13(10-22)days for platelet.Median follow-up time was 59.5 months and 5-year OS/PFS 70.0%(95% CI: 50.60%-89.40%)and 59.1%(95% CI: 39.11%-79.10%). And 5-year cumulative recurrence and non-recurrence mortality rates were 35.42%(95% CI: 19.11%-59.39%)and 4.2%(95% CI: 2.16%-29.87%). Conclusions:Asparaginase-based chemotherapy followed by auto-HSCT is both safe and efficacious for progressive ENKTL.

5.
Journal of Clinical Hepatology ; (12): 1030-1034, 2022.
Article in Chinese | WPRIM | ID: wpr-924771

ABSTRACT

Objective To investigate the onset of liver inflammation and related predictive factors in patients with HBeAg-positive chronic hepatitis B virus (HBV) infection who have normal alanine aminotransferase (ALT) and a high viral load. Methods A retrospective analysis was performed for the clinical data of 183 patients with HBeAg-positive chronic HBV infection who had normal ALT and a high viral load and were treated from October 2008 to May 2015, and according to the results of liver biopsy, they were divided into hepatitis group and non- hepatitis group. The t -test or Mann-Whitney U testwas used for comparison of normally distributed continuous data between groups, the chi-square test was used for comparison of categorical data. The predictive factors were analyzed by univariate binary logistic regression, the multivariate binary logistic regression was carried out by stepback method, and the cut-off values were analyzed by receiver operating characteristic curve (ROC) and Jordan index. Results There were 37 patients (20.2%) in the hepatitis group and 146 patients (79.8%) in the non-hepatitis group. Compared with the non-hepatitis group, the hepatitis group had a significantly lower proportion of male patients (45.9% vs 68.5%, χ 2 =6.508, P =0.011), a significantly higher level of aspartate aminotransferase [24 (21.25~35.55) U/L vs 21.2 (18.08~ 24.65) U/L, Z =-3.344, P =0.001], and a significantly lower log(HBsAg) value [4.4(4.28~4.49) vs 4.46(4.4~4.74), Z =-2.184, P =0.029]. Log(HBsAg) value was a predictive factor for hepatitis (odds ratio=0.077, P =0.017), and the cutoff value of HBsAg was 33884.4I U/mL. Conclusion Among the patients with HBeAg-positive chronic HBV infection who have normal ALT and a high viral load, 20.2% have liver inflammation, and HBsAg may be a predictive factor for liver inflammation.

6.
Journal of Clinical Hepatology ; (12): 148-153, 2022.
Article in Chinese | WPRIM | ID: wpr-913129

ABSTRACT

Objective To investigate the clinical features and autoantibody characteristics of patients with drug-induced liver injury (DILI). Methods A retrospective analysis was performed for the patients with abnormal liver function who were admitted to Beijing Ditan Hospital, Capital Medical University, from September 2014 to September 2018 and were diagnosed with DILI based on RUCAM score, and related data on admission were collected, including baseline liver function, renal function, routine blood test results, five immune indices, autoantibody, and liver biopsy results. The t -test was used for comparison of normally distributed continuous data between two groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups; the chi-square test was used to compare the detection rate of autoantibody between the patients with different sexes or types of liver injury. A logistic regression analysis was used to investigate whether autoantibody had a regression relationship with sex, age, and type of injury, and an ordinal logistic regression analysis was performed with baseline laboratory results as independent variables and anti-nuclear antibody (ANA) titer as the dependent variable. Results A total of 419 patients with DILI were enrolled in the study, with a median age of 47 (35-55) years, among whom male patients accounted for 32.5% (136/419) and female patients accounted for 67.5% (283/419). Among these 419 patients, 88 (21.5%) had hepatocellular-type liver injury, 87 (21.2%) had mixed-type liver injury, and 235 (57.3%) had cholestasis-type liver injury. The detection rate of autoantibodies was 50.6% (212/419), and the detection rate of ANA was 42.9% (180/419), with a titer of mainly 1∶ 100 (104/180). There was no significant difference in the detection rate of autoantibodies between the patients with different sexes ( χ 2 =2.658, P =0.103) or different types of injury ( χ 2 =0.859, P =0.651). The binary logistic regression analysis showed that autoantibody did not have a regression relationship with sex, age, and type of injury (all P > 0.05) There were significant differences in prothrombin time activity (PTA) and international normalized ratio (INR) between the positive autoantibody group and the negative autoantibody group ( t =2.161, P =0.031; Z =-3.010, P =0.003). The ordinal logistic regression analysis showed that INR (odds ratio [ OR ]=3.101, P =0.040) and IgG ( OR =1.043, P =0.014) were associated with ANA grade. Conclusion There is a relatively high detection rate of autoantibodies in patients with DILI, and the detection rate of autoantibodies is not associated with sex, age, or type of injury. There are differences in PTA and INR between autoantibody-positive patients and autoantibody-negative patients, and the levels of INR and IgG are correlated with antibody titer.

7.
Chinese Journal of Radiation Oncology ; (6): 29-34, 2022.
Article in Chinese | WPRIM | ID: wpr-932623

ABSTRACT

Objective:To introduce the clinical dosimetry commissioning methods and results of the 1.5 T MR-linac.Methods:In May, 2019, an Elekta Unity 1.5 T MR-linac was installed in Cancer Hospital, Chinese Academy of Medical Sciences and dosimetry commissioning was performed with magnetic field compatible measuring instruments. Commissioning items include absolute dose calibration, data acquisition and planning system model verification.Results:Absolute dose calibration in magnetic field should be corrected by magnetic field correction factor. The standard output dose of Unity was 87 cGy. Gamma analysis (3%/2 mm) was performed on the beam collection data and the planning system calculation data. The average pass rate of dose verification of standard field test cases was 96.41%, and the TG119 test case was 98.24%. The IROC end to end test case was 97.5%(7%/4 mm).Conclusions:The planning system model and the beam collection data have good consistency. The dose verification results of the standard field and TG119 test cases meet the general tolerance limit requirements of the AAPM TG218 report, and the verification results of the IROC end-to-end test cases meet the IROC center standards.

8.
International Journal of Cerebrovascular Diseases ; (12): 109-114, 2022.
Article in Chinese | WPRIM | ID: wpr-929891

ABSTRACT

Objective:To investigate the difference in efficacy between transsylvian-transinsular approach and transcortical-transtemporal approach for hematoma evacuation in the treatment of severe basal ganglia intracerebral hemorrhage in young adults.Methods:Young adult patients with severe intracerebral hemorrhage in the basal ganglia region underwent craniotomy hematoma removal in Ankang Central Hospital from February 2012 to February 2021 were retrospectively enrolled. The Glasgow Outcome Scale score was used to evaluate the outcome at 6 months after onset. 4-5 were defined as good outcome and 1-3 were defined as poor outcome. Multivariate logistic regression analysis was used to determine the independent influencing factors of the poor outcomes. Results:A total of 51 patients were enrolled. Their median age was 41 (interquartile range 39-43) years, and 29 were men (56.8%). The median Glasgow Coma Scale score at admission was 6.0 (interquartile range 5.5-7.0), and the median baseline hematoma volume was 38.0 ml (34.5-47.5 ml). Twenty-one patients (41.2%) were in the transsylvian-transinsular approach group and 30 (58.8%) were in the transcortical-transtemporal approach group. There were no significant differences in demographics, vascular risk factors and baseline clinical data between the transsylvian-transinsular approach group and the transcortical-transtemporal approach group. Compared with the transcortical-transtemporal approach group, the amount of intraoperative bleeding and hematoma residue in the transsylvian-transinsular approach group were less, the proportion of patients requiring decompressive craniectomy was lower (33.3% vs. 63.3%; χ2=4.449, P=0.035), and the duration of dehydration medication and hospital stay were shorter (all P<0.05). However, there was no significant difference in the good outcome rate between the two groups (66.7% vs. 56.7%; χ2=0.518, P=0.472). Multivariate logistic regression analysis showed that lower scores of Glasgow Coma Scale at admission (odds ratio 0.128, 95% confidence interval 0.017-0.977; P=0.047) and longer hospital stay (odds ratio 1.402, 95% confidence interval 1.065-1.844; P=0.016) were independently associated with the poor outcomes. Conclusion:For young adult patients with severe basal ganglia intracerebral hemorrhage who underwent hematoma removal, although there was no significant difference between the outcomes of patients with transsylvian-transinsular approach and transcortical-transtemporal approach, the former had more advantages.

9.
Chinese Journal of Thoracic and Cardiovascular Surgery ; (12): 590-595, 2022.
Article in Chinese | WPRIM | ID: wpr-958446

ABSTRACT

Objective:To investigate the risk factors of spinal cord injury after FET for ATAAD.Methods:We analyzed perioperative data of 111 patients with ATAAD who underwent FET in the First Affiliated Hospital of Nanjing Medical University from January 2020 to October 2021.Results:Eleven(9.9%)of 111 patients had postoperative spinal cord injury, which showed varying degrees of paralysis or paraplegia. There was no significant difference in age, sex, medical history, cardiopulmonary bypass time, aortic cross-clamping time, circulatory arrest time and FET length between spinal cord injury group and non-spinal cord injury group( P>0.05). Univariate analysis showed that aortic true lumen away from the spinal side( P<0.001) and the number of segmental arteries originating from the true lumen<3 in T9-L3( P<0.001), left subclavian artery involvement( P<0.05) and stent coverage at T8 or beyond( P<0.05) was associated with postoperative spinal cord injury. Multivariate Logistic analysis showed that aortic true lumen away from the spinal side( P<0.001) and the number of segmental arteries originating from the true lumen<3( P<0.001) in T9-L3 and left subclavian artery involvement( P<0.05) were independent risk factors for postoperative spinal cord injury. Conclusion:The pathogenesis of spinal cord injury is complicated. This study suggests that the occurrence of spinal cord injury is significantly related to aortic true lumen away from the spinal side and the number of segmental arteries originating from the true lumen<3 in T9-L3 and left subclavian artery involvement. It is of great clinical significance to identify the high risk factors of postoperative spinal cord injury as early as possible.

10.
Journal of Biomedical Engineering ; (6): 370-379, 2022.
Article in Chinese | WPRIM | ID: wpr-928234

ABSTRACT

There is a shared problem in current optical imaging technologies of how to obtain the optical parameters of biological tissues with complex profiles. In this work, an imaging system for obtaining the optical parameters of biological tissues with complex profile was presented. Firstly, Fourier transformation profilometry was used for obtaining the profile information of biological tissues, and then the difference of incident light intensity at different positions on biological tissue surface was corrected with the laws of illumination, and lastly the optical parameters of biological tissues were achieved with the spatial frequency domain imaging technique. Experimental results indicated the proposed imaging system could obtain the profile information and the optical parameters of biological tissues accurately and quickly. For the slab phantoms with height variation less than 30 mm and angle variation less than 40º, the maximum relative errors of the profile uncorrected optical parameters were 46.27% and 72.18%, while the maximum relative errors of the profile corrected optical parameters were 6.89% and 10.26%. Imaging experiments of a face-like phantom and a human's prefrontal lobe were performed respectively, which demonstrated the proposed imaging system possesses clinical application value for the achievement of the optical parameters of biological tissues with complex profiles. Besides, the proposed profile corrected method can be used to combine with the current optical imaging technologies to reduce the influence of the profile information of biological tissues on imaging quality.


Subject(s)
Humans , Diagnostic Imaging , Light , Optical Imaging , Phantoms, Imaging
11.
Chinese Journal of Radiation Oncology ; (6): 587-591, 2021.
Article in Chinese | WPRIM | ID: wpr-910432

ABSTRACT

Objective:To design a drum-shaped applicator through Monte Carlo simulation for breast intraoperative radiotherapy.Methods:Applicator designing process is as follows: first, determined the shape of the applicator based on the geometric characteristics of the breast tumor bed closed to the chest wall; second, calculated the scattering angle and dose rate of the electron beam after passing through a series of scattering foils of different thicknesses to determine the thickness of the scattering foil; thrid, modeled the layer according to the applicator′s geometric characteristics where modulator located, and designed the modulator through the relationship between the geometric characteristics of the layer and the surface dose of the applicator. EGSnrc/BEAMnrc and EGS4/DOSXYZ were employed to model the head of the Mobetron, the layer, the applicator, and to calculate the dose distributions.Results:The applicator has two components. The upper component is a 3cm-diametre cylindrical collimator with 0.5cm wall made of 0.3cm steel and 0.2cm water equivalent material (WEM), a 0.13cm-foil made of tansgen. The lower component is a 4cm-diametre drum made of 0.2cm WEM and a 0.14cm maximum thickness hill-shaped modulator made of steel. When the energy of electron beam was 12MeV, the dose rate was about 90.44 cGy/min, and the depth of the 50% isodose curve was 1cm.Conclusion:The applicator is successfully designed, and can obtain a drum-shaped dose distribution.

12.
Chinese Journal of Clinical Infectious Diseases ; (6): 9-15, 2020.
Article in Chinese | WPRIM | ID: wpr-869282

ABSTRACT

Objective:To compare the efficacy of the combination of abidol, lopinavir/ritonavir plus recombinant interferon α-2b (rIFNα-2b) and the combination of lopinavir/ritonavir plus rIFNα-2b for patients with COVID-19 in Zhejiang province.Methods:A multicenter prospective study was carried out to compare the efficacy of triple combination antiviral therapy and dual combination antiviral therapy in 15 medical institutions of Zhejiang province during January 22 to February 16, 2020. All patients were treated with rIFNα-2b (5 million U, 2 times/d) aerosol inhalation, in addition 196 patients were treated with abidol (200 mg, 3 times/d) + lopinavir/ritonavir (2 tablets, 1 time/12 h) (triple combination group) and 41 patients were treated with lopinavir/ritonavir (2 tablets, 1 time/12 h) (dual combination group). The patients who received triple combination antiviral therapy were further divided into three subgroups: <48 h, 3-5 d and >5 d according the time from the symptom onset to medication starting. The therapeutic efficacy was compared between triple combination group and dual combination group, and compared among 3 subgroups of patients receiving triple combination antiviral therapy. SPSS 17.0 software was used to analyze the data.Results:The virus nucleic acid-negative conversion time in respiratory tract specimens was (12.2±4.7) d in the triple combination group, which was shorter than that in the dual combination group [(15.0±5.0) d] ( t=6.159, P<0.01). The length of hospital stay in the triple combination group [12.0 (9.0, 17.0) d] was also shorter than that in the dual combination group [15.0 (10.0, 18.0) d] ( H=2.073, P<0.05). Compared with the antiviral treatment which was started within after the symptom onset of in the triple combination group, the time from the symptom onset to the viral negative conversion was 13.0 (10.0, 17.0), 17.0 (13.0, 22.0) and 21.0 (18.0, 24.0) d in subgroups of 48 h, 3-5 d and >5 d, respectively ( Z=32.983, P<0.01), while the time from antiviral therapy to viral negative conversion was (11.8±3.9), (13.5±5.1) and (11.2±4.3) d, respectively( Z=6.722, P<0.05). Conclusions:The triple combination antiviral therapy of abidol, lopinavir/litonavir and rIFNα-2b shows shorter viral shedding time and shorter hospitalization time, compared with the dual combination antiviral therapy; and the earlier starting triple combination antiviral therapy will result in better antiviral efficacy.

13.
Chinese Journal of Radiation Oncology ; (6): 963-967, 2020.
Article in Chinese | WPRIM | ID: wpr-868712

ABSTRACT

Objective:The Lorentz force produced by magnetic field deflects the paths of secondary electrons. The X-ray beam dosimetry characteristics of the magnetic resonance accelerator (MR-Linac) are different from conventional accelerators. The purpose of this study was to measure and analyze the X-ray beam dosimetry characteristics of 1.5T MR-Linac.Methods:In May 2019, our hospital installed a Unity 1.5T MR-Linac and measured it with magnetic field compatible tools. The measurement indexes include: surface dose, maximum dose point depth, beam quality, off-axis dose profile center, beam symmetry, penumbra width, output changes of different gantry angles.Results:The average surface dose was 40.48%, and the average maximum dose depth was 1.25 cm. The center of the 10 cm×10 cm beam field was offset by 1.47 mm to the x2 side and 0.3 mm to the y2 side. The x-axis symmetry was 101.33%, and the penumbra width on both sides was 6.86 mm and 7.14 mm, respectively. The y-axis symmetry was 100.85%, and the penumbra width on both sides was 5.92 mm and 5.95 mm, respectively. The maximum deviation of output dose with different gantry angles reached 1.50%. Conclusions:The surface dose of MR-Linac tend to be consistent, and the depth of the maximum dose point became shallower. The off-axis in the x-axis direction was shifted to the x2 side, which resulting in worse symmetry and penumbra asymmetry. The output dose at different angles has obvious variation and needs correction.

14.
Chinese Journal of Radiation Oncology ; (6): 877-881, 2020.
Article in Chinese | WPRIM | ID: wpr-868700

ABSTRACT

Objective:To compare the setup errors between deep inspiration breath hold (DIBH) and free breathing (FB) for breast cancer patients who were treated with whole breast irradiation (WBI) after breast conserving surgery (BCS).Methods:In this retrospective analysis, 30 breast cancer patients receiving WBI following BCS using DIBH in National Cancer Center/ Chinese Academy of Medical Sciences, an 30 patients treated with WBI using FB were enrolled as comparator.The kilovoltage cone-beam computed tomography (CBCT) was performed to evaluate and reduce setup errors. The optimal margins from clinical target volume (CTV) to planning target volume (PTV) for DIBH were estimated. The differences of setup errors between two techniques were compared using independent two-sample t-test. Results:A total of 318 sets of CBCT images were acquired, with (5.1±1.1) sets per patient on average. The setup errors along the three translational directions (laternal, longitudinal and vertical) were (2.1±1.6) mm, (2.6±1.7) mm and (2.5±2.1) mm for DIBH, and (2.2±1.7) mm, (3.1±2.5) mm and (3.3±2.3) mm for FB, respectively. Compared with FB, DIBH significantly reduced setup errors in the longitudinal ( P=0.015) and vertical ( P=0.004) directions, whereas the setup errors in the lateral direction did not significantly differ ( P=0.294). The optimal margins from CTV to PTV using DIBH were 6.2 mm, 7.3 mm and 7.8 mm, respectively. In the DIBH group, treatment fractions at the beginning and higher body mass index (BMI) did not associate with larger set-up deviation. Conclusions:DIBH technique yields less setup errors than FB for breast cancer patients treated with WBI after BCS. The CTV-PTV margins of 6-8 mm are recommended for DIBH.

15.
Chinese Journal of Radiation Oncology ; (6): 461-465, 2020.
Article in Chinese | WPRIM | ID: wpr-868618

ABSTRACT

Objective:To evaluate the effect of fast cone beam CT (CBCT) scan mode on image quality and registration results, and to establish the scanning pre-settings for fast CBCT.Methods:Three scanning modes were utilized to the CBCT phantom, and the registration accuracy and image quality were quantitatively evaluated. The correlation and consistency of measurement results under different scanning modes were further verified by 278 sets of CBCT data from 33 clinical tumor patients.Results:The maximum deviation between the measurement results of three scanning models and the actual value was 0.70 mm (0.51 mm on average). The measurement results of the same location were consistent among three scanning modes (0.00 mm). For the uniformity, the results of the normal mode were the best (3.62% on average), followed by the fast 1 mode (3.90% on average) and the fast 2 mode (4.84% on average). For the noise, the results of the normal mode were the best (15.69 on average), followed by the fast 2 mode (17.23 on average) and the fast 1 mode (21.74 on average). Regarding the high contrast resolution, the measurement results of three scanning modes were consistent (at least 3 pairs could be distinguished). For the low contrast resolution, the results of the fast 1 mode were the best (1.69 on average), followed by the normal mode (2.10 on average), and the fast 2 mode (2.31 on average). For the geometric accuracy, the measurement results of the three scanning modes were basically consistent with a mean deviation of 0.05 mm. The correlation of the measurement results between normal mode and fast 1 mode was the highest in clinical cases ( R2>0.90, P<0.01) with a high degree of consistency (95% consistency limit of the above two scanning modes< 1 mm threshold). Conclusion:Compared with the normal mode, the fast 1 mode can yield equivalent image quality, consistent registration results, faster scanning speed and lower scanning dose. Therefore, the fast 1 mode is recommended as the scan mode in clinical practice.

16.
Chinese Journal of Radiological Medicine and Protection ; (12): 868-872, 2020.
Article in Chinese | WPRIM | ID: wpr-868526

ABSTRACT

Objective:To design a semi-spherical applicator for delivery of semi-spherical dose distributions and assess its dosemetric characteristics.Methods:The applicator was designed in the following way. First, the scattering angle and dose rate of the electron beam having passed through a series of scattering foils of different thicknesses were calculated to determine the thickness of the scattering foil. And then, a series of location model was designed, and the variances of the mean electron energy on the surface of these models were calculated to determine the foil location. Finally, the relationship between the geometric characteristics of the layer and the surface dose on the applicator was established to design the modulator. Monte Carlo (MC) codes EGSnrc/BEAMnrc and EGS4/DOSXYZ were employed to model the head of the Mobetron, the location model, the layer, the semi-spherical applicator, and to calculate the dose distributions.Results:A semi-spherical applicator was designed for electron beam of energy 12 MeV, which consisted of a 2.5 cm diametre cylindrical collimator with 0.5 cm thick wall made of 0.3 cm thick steel and 0.2 cm thick water equivalent material (WEM), a 0.14 cm-thick foil made of tansgen, and a 2.5 cm diametre hollow semi-sphere containing a crescent modulator made of WEM. The dose rate was about 160 cGy/min, and the depth of the 50% isodose curve was 0.85 cm.Conclutions:We designed and performed a MC simulation of a semi-spherical applicator to deliver a semi-spherical dose distribution from a high energy electron beam.

17.
Chinese Journal of Clinical Infectious Diseases ; (6): E010-E010, 2020.
Article in Chinese | WPRIM | ID: wpr-811497

ABSTRACT

Objective@#Comparing the benefit of Abidor, lopinavir/ritonavir and recombinant interferon α-2b triple combination antiviral therapy and lopinavir/ritonavir and interferon dual combination antiviral therapy to hospitalized novel coronavirus pneumonia 2019 in Zhejiang province.@*Methods@#A multi-center prospective study was carried out to compare the effect of triple combination antiviral therapy with dual combination antiviral therapy in 15 medical institutions of Zhejiang Province. All patients were treated with recombinant interferon α-2b (5 million U, 2 times/d) aerosol inhalation. 196 patients were treated with abidol (200 mg, 3 times/d) + lopinavir / ritonavir (2 tablets, 1 time/12 h) as the triple combination antiviral treatment group. 41 patients were treated with lopinavir / ritonavir (2 tablets, 1 time/12 h) as the dual combination antiviral treatment group. The patients who received triple combination antiviral therapy were divided into three groups: within 48 hours, 3-5 days and > 5 days after the symptom onset. To explore the therapeutic effects of triple combination antiviral drugs and dual combination antiviral drugs, as well as triple combination antiviral drugs with different antiviral initiate time. SPSS17.0 software was used to analyze the data.@*Results@#The time of virus nucleic acid turning negative was (12.2 ± 4.7) days in the triple combination antiviral drug group, which was shorter than that in the dual combination antiviral drug group [(15.0 ± 5.0) days] (t = 6.159, P < 0.01 ). The length of hospital stay [12 (9, 17) d] in the triple combination antiviral drug group was also shorter than that in the dual combination antiviral drug group [15 (10, 18) d] (H = 2.073, P < 0.05). Comparing the antiviral treatment which was started within 48 hours, 3-5 days and > 5 days after the symptom onset of triple combination antiviral drug group, the time from the symptom onset to the negative of viral shedding was 13 (10,16.8), 17 (13,22) and 21 (18-24) days respectively (Z = 32.983, P < 0.01), and the time from antiviral therapy to the negative of viral shedding was (11.8±3.9) , (13.5±5.1) and (11.2±4.3) d. The differences among the three groups were statistically significant (Z=32.983 and 6.722, P<0.01 or<0.05).@*Conclusions@#The triple combination antiviral therapy of Abidor, Lopinavir/Litonavir and recombinant interferon α-2b showed shorter viral shedding time and hospitalization time compared with the dual combination antiviral therapy. The earlier the time to initiate triple antiviral treatment, the shorter the time of virus shedding.

18.
Chinese Journal of Radiation Oncology ; (6): 532-535, 2019.
Article in Chinese | WPRIM | ID: wpr-755066

ABSTRACT

Objective To investigate the setup errors and influencing factors of the whole breast intensity-modulated radiotherapy (IMRT) after breast-conserving surgery,and to identify the margins from clinical target volume (CTV) to planning target volume (PTV).Methods Thirty patients with left-sided (n=15) or right-sided breast cancer (n=15) receiving whole breast hypofractionated IMRT with breast board immobilization after breast-conserving surgery in Cancer Hospital from 2016 to 2017 were enrolled.The kilo-voltage cone-beam computed tomography (CBCT) was used to compare the errors of planning CT and treatment unit and determine the setup errors.The margins from CTV to PTV were calculated.The setup errors under different conditions were statistically compared by t-test.Results A total of 151 sets of CBCT images were taken in the whole cohort,(5.0± 1.3) sets per patient on average.The setup errors in the x-axis (left-right direction),y-axis (cranial-caudal direction) and z-axis (anterior-posterior direction) were (2.2± 1.7) mm,(3.1±2.5) mm and (3.3±2.3) mm,respectively.The margins from CTV to PTV were 6.39 mm,10.00 mm and 8.57 mm,respectively.The setup error in anterior-posterior direction in the first week was (3.7±2.5) mm,significantly larger than (2.6±1.6) mm in the following week (P=0.002).The setup error of the patients with overweight or obesity was (3.9±2.6) mm,significantly higher than (2.9±2.0) mm in those with normal weight in the z-axis direction (P=0.033).Conclusion The margins from CTV to PTV are recommended to be ranged from 6 to 10 mm during hypofractionated whole breast IMRT with breast board immobilization after breast-conserving surgery.More frequent imaging verification should be applied in the first week of IMRT.

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Chinese Journal of Radiation Oncology ; (6): 452-456, 2019.
Article in Chinese | WPRIM | ID: wpr-755049

ABSTRACT

Objective The IAEA report No.483 describes the latest method of small field dosimetry.The field output factor measurement and correction methods are used to improve the accuracy and consistency of the measurement results for different type detectors.Methods The field output factors from 0.6 cm×0.6 cm to 10 cm× 10 cm were measured using IBA's CC13 ionization chamber,CC01 ionization chamber,PFD semiconductor detector,EFD semiconductor detector and Razor semiconductor detector,respectively.The field output correction factors were used to correct the measurement result.Results Compared with the corrected data,the results of ionization chamber are mainly affected by the volume averaging and the fluence perturbation effect,lead to the measurement result which is 4.70% lower at 0.6 cm × 0.6 cm;The results of Shielded semiconductors are mainly affected by fluence perturbation effect,lead to the measurement result which is 4.80% higher at 0.6 cm × 0.6 cm.The results of unshielded semiconductors are mainly affected by energy response and fluence perturbation effect,resulting in lower measurement results at the field size>0.8 cm×0.8 cm,2.10% lower at field size of 1.5 cm× 1.5 cm,higher measurement results at field size<0.8 cm×0.8 cm and 1.1% higher at field size of 0.6 cm×0.6 cm.Before the correction,the measurement results from different types of detectors are quite different,average standard deviation is 0.016 6.After the correction,the difference among the detectors is significantly reduced,average standard deviation is 0.006 6.Conclusions For detectors such as ionization chambers and semiconductors,the field output correction factors can be used to correct the output factors of the small field to improve the accuracy and consistency of the measurement results.

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Chinese Journal of Radiation Oncology ; (6): 217-221, 2019.
Article in Chinese | WPRIM | ID: wpr-745285

ABSTRACT

Objective To quantify the setup errors measured with kV cone-beam CT (CBCT) using breast board with or without a thermoplastic head mask in breast cancer patients who received whole breast and supraclavicular nodal region irradiation.Clinical target volume (CTV) to planning target volume (PTV) in 3 directions were also calculated.Methods The study included thirty patient receiving both whole breast and supraclavicular nodal region irradiation on Elekta Versa HD linear accelerators (Elekta Oncology Systems,Crawley,UK) between June 2016 and January 2018.The setup error data were retrospectively analyzed.All the patients were immobilized in the supine position on a breast board system (Carbon fibre breast board,Civco,Iowa,USA) with both arms raised.Twenty of the patients added an extra thermoplastic head mask to immobilize the neck.A CBCT scan was taken before treatment at the first 3 to 5 fractions and then once every week.Registration with the planning CT was performed and adjusted to match the target volume of the supraclavicular nodal region and the cervical vertebra by experienced medical staff,the position of the arms and the breast were also considered.For all patients the couch shifts in left-right (x),superior-inferior (y),anterior-posterior (z) were recorded.Statistical analysis included two-tails significance tests (t-Student and Manne-Whitney test for means,x2 test for variances).Population of the two groups was compared in terms of distribution of the mean shift (systematic error) and their standard deviations (random error).Van Herk's setup margin defined as MPTV =2.5Σ + 0.7δ was calculated in patients with or without mask immobilization.Results Altogether,56 images and 109 images were acquired in breast board only group and head mask group,respectively.Shifts of the breast board only group and the head mask group in x,y,z were 0.212±0.174 cm vs.0.272±0.242 cm (P=0.070);0.364±0.246 cm vs.0.242±0.171 cm (P=0.001);0.423±0.302 cm vs.0.364±0.269 cm (P=0.204).Proportion of the shift less than 5 mm in the breast board only group and the head mask group were 91.07% vs.85.32% (P=0.294);67.86% vs.89.91% (P=0.001);67.86% vs.74.31% (P=0.381).The CTV to PTV margin in x,y,z were 0.645 cm,0.981 cm,1.317 cm in breast board only group and 0.873 cm,0.709 cm,0.961 cm in head mask group,respectively.Setup error in the x direction was significantly correlated with BMI (P=0.001).Conclusions For the alignment and immobilization of patients who received whole breast and supraclavicular nodal region irradiation,using a breast board in combination of a thermoplastic head mask may significantly help to reduce the shift variance in superior-inferior direction compared to using breast board only.The anterior-posterior error is relatively large,other immobilization device or patient alignment methods are needed to be further explored to improve the accuracy.

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