Objective To study the spectrum structure of X-ray and simplify the description method of it. Methods By the general program of Monte Carlo Geant4 to study X-ray spectrum structure and angular distribution of X-ray energy spectrum. Results The results of percentage depth doses and profile curves at different depths of any radiation fields in water phantom calculated by Monte Carlo Geant4 were consistent with the measurements. Conclusions In radiotherapy, X-ray with same nominal energy have very similar dosimetry characteristics, this indicates they have very similar energy spectrum and angular distribution of spectrum. the differences of dosimetric details reflect the different details of the X-ray spectrum structure and angular distribution of X-ray energy spectrum. These studies have very important significances to rapidly build precise virtual source modeling for Monte Carlo calculation based on dose curves measurements in water phantom.

ObjectiveTo analyze the effects of high-order scattered X-ray in dose calculation in radiotherapy,to resolve the problem of correcting the dose contribution of secondary and high-order scattering X-ray to the primary scattered X ray,and to provide a support for photon fast dose calculation method of Monte Carlo.MethodsBy the theory of cross-section in interaction between X-ray with material and Monte Carlo calculating results,to analysis the relative importance of primary scattered X-ray,secondary and high-order scattered of X-ray in dose calculation.ResultsThe contribution of secondary and high-order scattered X-ray to dose calculation was very small,it can be corrected to the primary scattered X-ray with a correction factor.ConclusionsThe results show that we can obtain a precise dose calculation for radiotherapy by only to tracking the contribution of primary X-rays and primary scattering X-ray,so,to establishing the database for primary scattering X-ray by Monte Carlo methods is important for fast dose calculation of Monte Carlo method.

Objective To study the growth suppressive effect of demethylation drug 5-aza-2'-deoxycytidine on bladder tumor cells. Methods The growth suppressive effect of DAC on 4 transitional cell carcinoma (TCC) cell lines was measured using the Cell Proliferation Reagent WST-1 assay.The effects of DAC on apoptosis induction and cell cycle arrest were analyzed by flow cytometric analysis. Caspase 3, 9 activities were analyzed by APOPCYTO Caspase Colorimetric Assay Kit and PCNA expression was also investigated by Western blot to clarify the mechanism of DAC against TCC. Results DAC inhibited the growth of all TCC cell lines tested in a dose-dependant manner, however,growth suppressive effect of DAC was independent of p53 status in TCC. DAC inhibited proliferation via inducing G2/M cell cycle arrest but not via inducing apoptosis. After treated with 0, 1 and 8 μmol/L DAC, cells of RTl 12 in G2/M phase was (36.3 ± 3.4) %, (46.2 ± 4.6) % and (56.5 ±6.2) %, TCCsup was (37.5 ± 3.8) %, (48.4 ±4.9) % and (60.1 ± 6.7) %, respectively. The expression of PCNA was decreased by DAC, but caspase3, 9 activities were not activated. Conclusion DAC could suppress the growth of TCC cells and might be a new strategy to treat bladder malignancy in the future.

Objective To observe the anti-proliferation effects of rapamycin and paclitaxel of different hu-man prostate cancer cells in vitro. Methods The methods of MTr and flow cytometry were respectively ap-plied to observe the effect of rapamycin, paclitaxel and rapamycin+paclitaxel on proliferation and apoptosis of different prostate cancer cell lines (LNCaP-C4, LNCaP-C4-2, PC-3). Results When the concentration of rapamycin was 0.01 μmol/L, the impressive effect showed a remarkable difference in contrast to the con-trol. While in group LNCaP-C4-2 and PC-3, the goal concentration of rapamycin was 0.001μmol/L. When the concentration of paclitaxel was 0. 2 ng/mL, the impressive effect showed a remarkable difference in con-trast to the control. In group rapamycin (10 nmol/L) and in group paclitaxel (1 ng/mL) there were signifi-cant differences in growth inhibition, compared with control. While in group rapamycin(5 nmoL/L)+pacli-taxel(0.5ng/mL) there was significant difference in growth inhibition, compared with rapamycin (10 nmol/L) and paclitaxel (1 ng/mL) respectively. After cultured with rapamycin or paclitaxel alone, more tumor cells induced apoptosis than control. While after cultured with rapamycin and paclitaxel simultaneously, more tumor cells induced apoptosis than with rapamycin or paclitaxel alone. Conclusions Both rapamycin and paclitaxel had a good impressive effect on the three prostate cell lines (LNCaP-CA, LNCaP-C4-2, PC-3) with dose-dependent manner. After cultured with rapamycin and paclitaxel simultaneously, more tumor cells were induced apoptosis than with rapamycin or paclitaxel alone.