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Objective To explore the dose of template-assisted 192Ir source hypofractionated stereotactic brachytherapy (SABT) for peripheral lung cancer. Methods We retrospectively analyzed the dose parameters of GTV and OARs of 28 peripheral lung cancer patients treated with template-assisted 192Ir-source hypofractionated SABT, and compared the dose parameters between SABT with virtual SBRT. Results The Dmean and V150 for the GTV in the SABT plan were significantly higher than those in the SBRT plan (all P < 0.01). For OARs, all dosimetric parameters in the SABT plan were significantly lower than those in the SBRT plan (all P < 0.01), except for the D1000cm3 and D1500cm3 for the lung (P > 0.05). Conclusion Template-assisted 192Ir source hypofractionated SABT ensures high dose in the gross tumor volume and reduces the dose in organs at risk in the treatment of peripheral lung cancer.
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Objective@#To preliminarily evaluate the safety of the coplanar template-assisted 192Ir hypofractionated stereotactic ablative brachytherapy (SABT) in patients with locally advanced non-small cell lung cancer (LA-NSCLC), and assess the effect of template-assisted technology upon the accuracy of SABT by comparing the consistency of dosimetric parameters between preoperative and operative plans.@*Methods@#Fifteen patients histologically confirmed with LA-NSCLC (stage ⅡB-ⅢA) were recruited and received the template-assisted SABT delivered in a risk-adapted fractionation (30 Gy/1F). Preoperative planning, template-assisted needle implantation, operative planning and implementation were performed in all patients. Dosimetric results of preoperative and operative plans were statistically compared by assessing the dosimetric parameters of gross tumor volume (HI, CI, D90, V100 and V150) and organ at risk(V5, V20 and mean dose of bilateral lung, D2cc of spinal cord. The incidence of perioperative complications of SABT was recorded. The safety and feasibility of SABT were evaluated.@*Results@#Slight changes were noted in terms of target dose and irradiated dose to the lung between preoperative and operative plans without statistical significance (both P>0.05). No severe adverse events, such as severe pneumothorax, hemothorax and hemoptysis were observed.@*Conclusions@#Application of the template-assisted SABT can enhance the accuracy of implantation, maintain the consistency of the dosimetric parameters between the preoperative and operative plans and guarantee the clinical efficacy.
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Objective To preliminarily evaluate the safety of the coplanar template-assisted 192Ir hypofractionated stereotactic ablative brachytherapy (SABT) in patients with locally advanced non-small cell lung cancer (LA-NSCLC),and assess the effect of template-assisted technology upon the accuracy of SABT by comparing the consistency of dosimetric parameters between preoperative and operative plans.Methods Fifteen patients histologically confirmed with LA-NSCLC (stage ⅡB-ⅢA) were recruited and received the template-assisted SABT delivered in a risk-adapted fractionation (30 Gy/1F).Preoperative planning,template-assisted needle implantation,operative planning and implementation were performed in all patients.Dosimetric results of preoperative and operative plans were statistically compared by assessing the dosimetric parameters of gross tumor volume (HI,CI,D90,V100 and V150) and organ at risk (V5,V20 and mean dose of bilateral lung,D2cc of spinal cord.The incidence of perioperative complications of SABT was recorded.The safety and feasibility of SABT were evaluated.Results Slight changes were noted in terms of target dose and irradiated dose to the lung between preoperative and operative plans without statistical significance (both P＞0.05).No severe adverse events,such as severe pneumothorax,hemothorax and hemoptysis were observed.Conclusions Application of the template-assisted SABT can enhance the accuracy of implantation,maintain the consistency of the dosimetric parameters between the preoperative and operative plans and guarantee the clinical efficacy.
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Objective To explore the relationship between the overlap volume of organ at risk (OAR) and target (Voverlap) and the mean dose to OAR (DmOAR) in intensity-modulated radiotherapy (IMRT).Methods Fifty randomly selected patients undergoing IMRT for nasopharyngeal carcinoma (NPC) and an equal number of patients undergoing radical IMRT for cervical cancer in our hospital were enrolled as subjects.The relationship between Voverlap and DmoAR in IMRT was analyzed.The Matlab software was used to generate function to fit the relationship between Voverlap and DmOAR for different OARs.Results The Voverlap varied among patients with NPC or cervical cancer.The ratio of Voverlap to the volume of OAR (VOAR) was positively correlated with the ratio of DmOAR to the prescribed dose (Dp) (all P=0.01).A function was generated to fit the correlation between Voverlap/VOAR ratio and DmOAR/Dp ratio.Conclusions In IMRT,patients have different Voverlap/VoAR ratios due to varicd target volume,disease stages,OAR filling status,and OAR volume.As criteria for plan verification,a specific DmOAR value for each OAR should be calculated before radiotherapy planning based on the corresponding correlation function and the Voverlap/VoAR ratio with a fixed dose prescription.It can be used to reduce the subjective influence on the optimization of radiotherapy planning.
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Objective To analyze the effect of needle arrangement on the lung dose in interstitial brachytherapy for lung cancer. Methods For 15 patients undergoing interstitial brachytherapy for lung cancer, a virtual radiotherapy plan in which needle arrangement was not restricted by the ribs was designed and compared with the original plan. For the two plans, V5, V20, V30, and mean lung dose(MLD)of the whole lung were determined when the prescribed doses were 10,30, 60, and 120 Gy, respectively. The data were analyzed by Wilcoxon signed-rank test. Results The lung V5,V20, V30, and MLD were significantly smaller in the virtual plan than in the actual plan(all P<0.05). Conclusions Irregular needle arrangement prevents a further reduction in the lung dose in interstitial brachytherapy for lung cancer. In the implantation surgery, therefore, the needles should be arranged as regularly as possible.
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Objective: To apply level set motion-based elastic registration method to radiotherapy CT image, then to provide technical support for the accurate evaluation of tumor and changing process of patients with endanger organ and its accumulative dose. Methods: Based on Vemuri’s level set motion method, we wrote the algorithm program using Matlab software and applied on two sets of 3D CT images from patients with cervical cancer and NPC for fully automatic elastic registration. Results: Comparing CT images before and after registration, for the cervical cancer patient, the minimum mean square error (MSE) decreased by 55.1%and correlation coefficient (CC) increased by 5.3%. For the NPC patient, MSE decreased by 32.1%and CC increased by 4.6%. Conclusion: From the image difference and evaluation parameters, the efficacy of level set motion-based elastic registration method was preliminarily demonstrated. In order to apply this method to clinical radiotherapy, dit needs to find a more accurate mathematical algorithm further in order to compute human anatomy deformation through image motion.
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AIM: To investigate the effect of selective silencing of SLC7a8 on uptaking L-dopa in renal tubular epithelial cells of rat (NRK-52E). METHODS: The three siRNAs targeting SLC7a8 (siRNA-1, siRNA-2, siRNA-3) were designed and synthesized. A siRNA with nonspecific coding sequence (siRNA-con) was used for control. All siRNAs were transfected into NRK-52E cells. The siRNA-con transfected group, blank control group and gene-specific silencing SLC7a8 group were set up. The efficiency of transfection was estimated by flow cytometry. The efficiency of RNA interference was detected and screened by RT-PCR preliminarily, and was followed by Western blotting at protein level. The concentrations of L-dopa uptake into the NRK-52E cells were detected by ultraviolet spectrophotometry at different time points (6, 12, 24, 36, 48, 60, 72 and 120 min). RESULTS: The transfection efficiency was 94% detected by flow cytometry. The initial screening of RT-PCR showed that the efficiencies of RNA interference of siRNA-1 and siRNA-3 were higher, and siRNA-3 was the highest at protein level determined by Western blotting. No distinctive change was found between siRNA-con treated NRK-52E and blank control cells. The L-dopa uptake at different time points (6, 12, 24, 36, 48, 60, 72 and 120min) in siRNA-interference group was lower than that in siRNA-con transfected group and blank control group. No significant difference of L-dopa uptake between siRNA-con group and blank control group was observed. CONCLUSION: RNA interference technology selectively down-regulates SLC7a8 expression in rat renal tubular epithelial cells. The L-dopa uptake is also decreased after specifically silencing the slc7a8 expression.
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AIM: To investigate the downstream genes of the transcriptional factor Pax-8 related to cardiopathy. METHODS: The total RNA derived from the heart of Pax-8 KO~(-/-) and Pax-8 KO~(+/-) mice was extracted. Mouse genome DNA microarray containing 31 802 mouse oligonucleotides probes was used to investigate the differential expression between the Pax-8 KO~(-/-) and the Pax-8 KO~(+/-) mice hearts. The candidate genes were confirmed by RT-PCR and real time RT-PCR assay. RESULTS: Microarray results showed that, compared to the Pax-8 KO~(+/-) mice, 25 genes were down-regulated and 17 were up-regulated in the Pax-8 KO~(-/-) mice, concerning metabolize enzymes, cell signal conducting and nuclear transcript factors and so on. Bcl2-like 14 (Bcl2l14) was proved to be up-regulated by RT-PCR. Real time RT-PCR results revealed that Bcl2l14 in the Pax-8 KO~(-/-) mice was 2.07 and 2.23 fold as much as that in the Pax-8 KO~(+/-) and the Pax-8KO~(+/+) mice (P<0.01). CONCLUSION: The Bcl2l14 gene is one of the downstream genes of Pax-8 and probably plays an important role in the mechanism of ventricular septum defect.