Objective To investigate the effect of SKP2 expression on radiation induced bystander effect (RIBE) of esophageal cancer cells.Methods The esophageal cancer cell lines with different SKP2 levels were applied for the study and the SKP2 expression was identified by Western blot.Micronuclei (MN) assay and DNA foci assay were used to evaluate the effect of SKP2 on RIBE.The cells were transfected with SKP2 gene or SKP2 siRNA to further verify the effect of SKP2 on RIBE.Results MN assay showed that the bystander effect induced by the cells with a high level of SKP2 was lower than that induced by the cells with a lower level of SKP2 (t =8.06,P ＜ 0.01).These results were further confirmed by the gene transfection experiments.When the expression of SKP2 was increased,RIBE was decreased (t=11.12,10.16,P ＜ 0.01).Contrarily,when the expression of SKP2 was reduced,RIBE was increased (t =8.39,8.83,P ＜ 0.01).γ-H2AX foci formation assay disclosed that when SKP2 expression in the irradiated cells increased,the repair ability of DNA damage in the bystander cells was higher than the control (t =6.85,7.10,P ＜ 0.01).With the expression of SKP2 decreased,the repair ability of DNA damage was lower than the control (t =7.66,8.47,P ＜ 0.01).Conclusions Over-expression of SKP2 inhibits RIBE of esophageal cancer cells,at least partly through regulating DNA damage repair ability.

Objective To evaluate the efficacy of superficial temporal artery(STA)pressure-guided selective cerebral perfusion(SCP)during deep hypothermic circulatory arrest(DHCA)in patients undergoing aortic arch surgery.Methods Ninety-six patients of both sexes,aged 35-64 yr,with body mass index of 19-23kg/m2,of American Society of Anesthesiologists physical status Ⅲ or Ⅳ,undergoing aortic arch surgery,were divided into STA pressure group(group A)and clinical experience group(group B)using a random number table,with 48 patients in each group.In group A,STA catheterization was performed after tracheal intubation,and arterial pressure was monitored.SCP flow was adjusted to maintain the target value of STA pressure between 30 and 40mmHg during DHCA in group A.SCP flow rate was set at 5-10ml·kg-1·min-1 according to clinical experience in group B.The volume of fluid perfused during SCP,emergence time,extubation time and duration of intensive care unit stay were recorded.Neurological function was evaluated during length of hospitalization after surgery,and the development of permanent and transient neurological dysfunction and mortality in hospital were recorded.Results Compared with group B,the volume of fluid perfused during SCP was significantly decreased,the emergence time,extubation time and duration of intensive care unit stay were shortened,the incidence of permanent and transient neurological dysfunction(2% and 4%,respectively)was decreased(P < 0.05),and no significant change was found in the mortality rate in hospital in group A(P>0.05).Conclusion Maintaining STA pressure at 30-40mmHg is a reliable method for guiding SCP during DHCA in patients undergoing aortic arch surgery.

In patients with medullary thyroid carcinoma (MTC), calcitonin (Ctn) and carcinoembryonic antigen (CEA) were the most important serum biomarkers for diagnosis, evaluation and follow-up. Approximately 0.3% to 5.9% of the thyroid nodule population could present with elevated Ctn on screening, and a diagnosis of MTC can be basically confirmed when serum Ctn > 100 pg/ml.. Ctn and CEA levels could reflect tumor burden and help determine the extent and timing of surgery. When preoperative serum Ctn >200 pg/mL or CEA >30 ng/mL, nearly more than one-third of patients had lateral neck lymph node metastasis. Few patients developed distant metastasis when Ctn<500 pg/mL, however the proportion of distant metastasis could reach 75% when CEA>100 ng/mL. In inherited MTC patients, tumors with Ctn<30 pg/mL were usually localized in the gland without metastasis. The time to normalization of serum Ctn and CEA postoperatively was one month in most patients. According to the response to initial therapy, patients with undetectable Ctn and normal CEA had a low risk of relapse and death in the follow-up period. The risk of local recurrence, LNM and distant metastasis increased as Ctn levels rose. The Ctn/CEA doubling time could predict the disease prognosis, and when it was less than 0.5 years, most patients would die.

Objective:To calculate the conversion coefficient from dose area product (DAP) to organ absorbed dose by Monte Carlo method in order to conveniently estimate doses to patient organ during coronary intervention procedure.Methods:The Geant4 Monte Carlo simulation kit was used to calculate the organ absorbed dose conversion coefficients by simulating exposure scene.Results:The conversion coefficients used in coronary angiography (CAG) for lung, bone marrow, liver and heart were (0.283±0.068), (0.169±0.049), (0.110±0.077) and (0.080±0.032) mGy/(Gy·cm 2) for male, and (0.376±0.121), (0.192±0.056), (0.153±0.105), and (0.102±0.033) mGy/(Gy·cm 2) for female, respectively. These were similar to those in the case of percutaneous coronary intervention (PCI). The DAPs for different interventional procedures were statistically significant ( t=-6.012, P<0.05). The DAPs for difference gender groups had no statistically significant ( P>0.05). Conclusions:Conversion coefficient for organ absorbed dose has little correlation with CAG and PCI in the same sex group. Dose conversion coefficients for female group are greater than those for male group in the same procedure. Conversion coefficients from DAP to organ absorbed dose calculated with Monte Carlo method can provide convenience for rapidly estimating the organ absorbed dose to clinical patients.

Objective:To establish a metaheuristics-based automatic radiotherapy treatment planning method (ATP-STAR) and verify its effectiveness.Methods:The main process of the ATP-STAR method was as follows. First, the optimization parameters were vectorized for encoding and corrected using Gaussian convolution. Then, the candidate optimization parameter vector set was selected through simulated annealing. Finally, the optimal combination of optimization parameters was determined by combining the field fluence optimization to achieve automatic trial-and-error. Twenty cases with large individual differences in tumors were selected for testing. Clinical physicists with more than five years of experience were invited to perform manual planning. Both the manual and ATP-STAR plans were made utilizing the matRad open source software for radiation treatment planning, with the fields and prescribed doses consistent with those of the clinical treatment plans. The dosimetric differences of target volumes and organs at risk between the ATP-STAR and manual plans for different diseases were analyzed.Results:For the target volumes, the ATP-STAR plans showed superior homogeneity compared with the manual plans (brain tumors: z = 2.28, P = 0.022; lung cancers: z = 2.29, P = 0.022; liver cancers: z = 2.11, P = 0.035). The conformability of the ATP-STAR plans was comparable to that of the manual plans for brain tumors and liver cancer and was slightly lower than that of the manual plans for lung cancer ( z = 2.29, P = 0.022). The comparison result of doses to organs at risk (OARs) between the manual plans and STAR plans were as follows. For OARs of brain tumors, the ATP-STAR plans decreased the mean left lens Dmean from 2.19 Gy to 1.76 Gy ( z = 2.28, P = 0.022), decreased left optic nerve Dmean from 11.36 Gy to 10.22 Gy ( z = 2.28, P = 0.022), decreased right optic nerve Dmax from 32.92 Gy to 29.97 Gy ( z = 2.10, P = 0.036), and decreased pituitary Dmax from 39.53 Gy to 35.21 Gy ( z = 2.29, P = 0.022). For OARs of lung cancer, the ATP-STAR plans decreased the mean spinal cord Dmax from 38.00 Gy to 31.17 Gy ( z = 2.12, P = 0.034), decreased the bilateral lungs Dmean from 8.51 Gy to 8.07 Gy ( z = 2.29, P = 0.022), and decreased cardiac Dmean from 3.21 Gy to 2.69 Gy ( z =2.29, P = 0.022). For OARs of liver cancer, the ATP-STAR plans decreased spinal cord Dmax from 18.19 Gy to 14.76 Gy ( z = 2.11, P = 0.035), decreased liver Dmean from 15.61 Gy to 14.45 Gy ( z = 2.11, P = 0.035), and decreased kidneys Dmean from 4.76 Gy to 4.04 Gy ( z = 2.10, P = 0.036). Conclusions:The proposed ATP-STAR method relies little on the experience of manual planning and thus is easy to be widely applied. This method is expected to improve the quality and consistency of IMRT plans and save clinical labor and time costs.

Objective:To investigate the effects of off-target isocenter plans with different off-target distances on the plan quality and delivery accuracy of stereotactic body radiotherapy (SBRT) for lung cancer, aiming to provide a reference for the clinical plan design of SBRT for lung cancer.Methods:For 10 lung cancer patients treated with SBRT, isocenter reference plans were designed by setting the plan isocenters at the mass centers of tumors and 60 off-target isocenter plans by setting the isocenters at distances of 1, 3, 5, 8, and 10 cm from the mass centers of tumors. The dosimetric differences between the off-target isocenter plans and the reference plans. Subsequently was analyzed, under different positional errors (0-5 mm). The gamma pass rates (GPRs) of these plans were measured using the Octavius 4D high-resolution dose verification system, and 240 verifications of these plans were completed. The robustness of the delivery accuracy of the reference plans and off-target isocenter plans were analyzed under different positional errors.Results:The off-target isocenter plans yielded slightly worse dose gradient indices than the isocenter reference plans, but there was no statistically significant differences. With an increase in the off-target distance, the mean lung dose (MLD), V20 of normal lungs, as well as the Dmax of bronchi, showed slight upward trends. Compared with the isocenter reference plans, the MLD of the off-target isocenter plans increased by 0.8%, 0.8%, and 1.9% at off-target distances of 1, 3, and 10 cm, respectively, with statistically significant differences ( z = -2.34 to -1.99, P < 0.05), and the V20 of the off-target isocenter plans increased by 2.0%, 2.5%, and 3.7% at off-target distances of 1, 5, and 10 cm, respectively, with statistically significant differences ( z =-2.11 to -1.99, P < 0.05). In the case of a positional error of up to 5 mm, the GPRs of plans with off-target distances of 5 cm and above decreased by more than 1.0% on average and up to a maximum of 3.5%, showing statistically significant differences ( z = 2.13-2.75, P < 0.05). Conclusions:Compared to the reference plans, the off-target isocenter plans showed slightly lower dosimetric quality and less robust delivery accuracy under different positional errors. Therefore, it is necessary to avoid the plans and treatment with too large off-target distances (≥ 5 cm) as far as possible for SBRT of lung cancer.