ABSTRACT
Objective To compare the dosimetric effects of micro-multileaf collimator (MLC)(2 mm leaf width) and conventional MLC (10 mm leaf width) on inverse intensity-modulated radiotherapy(IMRT) in intracranial stereotactic radiosurgery(SRS). Methods In view of the fact that the micro-MLC has a small open field,30 patients with intracranial tumor with a<10 cm diameter were enrolled in this study. Their inverse dynamic IMRT plans were established using conventional MLC (conventional group) and micro-MLC (micro group) with the same other conditions. The radiation doses to the target volume and the organs at risk (OAR) were compared between the two groups with t test. Results Compared with the conventional group, the micro group had a significantly better dose distribution in the target volume (P=0.019). However, there were no significant differences in D98,D95,D50,and D3between the two groups (P=0.774,0.650,0.170,0.080). The micro group had a 58.7% lower mean homogeneity index and a 20.1% higher mean conformity index than the conventional group (P=0.000). The micro group had significantly lower radiation doses to OAR than the conventional group (P=0.044). The mean Dmeanand Dmaxof the brain stem in the micro group were 10.0% and 8.2%,respectively,lower than those in the conventional group (P=0.768,0.753). The mean Dmeanand Dmax of the right eye and left eye in the micro group were 16.5%,19.3%,21.4%,and 13.4%,respectively,lower than those in the conventional group (P=0.572,0.775 and 0.734,0.630). The mean Dmaxof the left lens, right lens, left optic nerve, right optic nerve, and optic chiasm in the micro group were 50.4%, 24.1%, 38.5%, 27.8%, and 5.7%, respectively, lower than those in the conventional group (P=0.172,0.467, 0.521,0.740,0.899). The PRV100,PRV50,and PRV25of the normal tissue in the micro group were no more than those in the conventional group(P=0.839,0.832,0.972). Conclusions In inverse IMRT in intracranial SRS,micro-MLC is better than conventional MLC because it can improve CI of the target volume and reduce the radiation doses to OAR.
ABSTRACT
Objective To investigate the mechanism of an inhibitor of NADPH oxidases,diphenylene iodonium (DPI),in preventing radiation-induced lung injury.Methods Totally 48 adult SD male rats were randomly classified into 4 groups:control group (C),radiation group (R),radiation plus DPI group (R + D) and DPI group (D).The radiation induced pulmonary injury model was preformed by using 6 MV X-rays to deliver 8 Gy per day for 5 consecutive days with 40 Gy in total to the thorax of each animal.Rats in R + D group were subcutaneously administered with 0.02％ DPI (1 mg/kg) at 1 h prior to radiation while rats in D group received the same dose of DPI without radiation.DPI was given from 3 d before radiation to 30 d after the first radiation.Rats in C and D groups received the same dose of saline.Animals were sacrificed at 1 month and 6 months after radiation,respectively.The lungs were removed and processed for HE and Masson staining,hydroxyproline content measurement,and TGF-β1 immunohistochemical detection.Results At 1 month post-radiation,rats in R group showed typical alveolitis,the level of hydroxyproline was (0.69 ± 0.05) μg/mg,and the positive area of TGF-β1 expression was (39.97 ± 0.90) ％,while the level of hydroxyproline in R + D group was (0.55 ± 0.03) μg/mg and the positive area of TGF-β1 expression was(33.83 ± 1.55) ％,rats in R + D group showed less severe alveolitis compared with R group(t =5.32,5.93,P ＜0.05).At 6 months post-radiation,rats in R group showed typical lung fibrosis with hydroxyproline level of (1.04 ±-0.02) μg/mg and TGF-β1 expression of (37.80 ± 0.85) ％,whereas the hydroxyproline level in R + D group was (0.85 ± 0.02) μg/ mg,the TGF-β1 expression was(23.93 ± 1.16)％,rats in R + D group showed moderate lung fibrosis(t =15.77,16.68,P ＜ 0.05),rats in C and D group had no noticeable changes.Conclusions Diphenylene iodonium could prevent radiation-induced lung injury by reducing the level of hydroxyproline and the expression of TGF-β1.
ABSTRACT
Objective To investigate the phosphorylation and dephosphorylation of CDK1 based on the specific cell cycle apoptosis in Molt-4 cells and active variety of CDK1 in cell cycle specific apoptosis.Methods The exponential phase of growth Molt-4 cells (the human acute lymphoblastic leukemia cell line) were induced with dose response and time course of Camptothecin (CPT).The specific cell cycle apoptosis was detected with API method,then cell apoptosis was verified with post sorting confocal method.Meanwhile,the phosphorylation and dephosphorylation of CDK1 were detected by the protein electrophoretic analysis (Western blot).Results The specific cell cycle apoptosis occurred on exponential phase of growth Molt-4 cells after CPT treatment.When Molt-4 cells occured S-phase apoptosis, the apoptosis cell phosphorylation of CDK1-Thr161 band was more narrow than that of control cells, the apoptosis cell phosphorylation of CDK1-Thr15 band almost had the same band with control cells.Conclusion Cell apoptosis frequently developed in different cell cycle phase. API assay is quick and efficient method to analyze specific cell cycle apoptosis. When cell apoptosis take place in S-phase,the phosphorylation activity of CDK1 is inhibited.