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Objective To explore the effect of β-element on the oadiosensitivity of transplanted tumor, and its relationship with the expression of survivin. Methods The transplanted mice model was established through the cell suspension inoculation. The mice with transplanted tumor size of 0. 8-1.0 cm3 were randomly divided into 8 groups as blank control, 25, 45 and 100 mg/kg group, irradiation group,25 mg/kg + irradiation group, 45 mg/kg + irradiation group, 100 mg/kg + irradiation group. The tumor size was measured every other day until tumor size was double, and the growth curve was obtained. The average tumor growth inhibition rate of β-element and tumor size were attained at 2,4,6 and 8 d after β-element injection. The expression of survivin was detected with immunohistochemistry. Results The nude mice model was successfully established and the growth curves were obtained according to the tumor size.Between 2 and 8 d after β-elemene injection, the variation tendency of the average tumor growth inhibition rate was consistent with the size in β-elemene treatment groups. The antitumor effect of β-elemene was in a dose-dependent manner. The values of radiosensitivity enhancement factor were 0. 84,1.24,2.04 for 25,45 and 100 mg/kg group, respectively ,and the optimal dose was 45 mg/kg. β-element had little effect on the expression of survivin, and the expression of survivin significantly enhanced in irradiation group and decreased in β-element + irradiation groups. Conclusions β-elemene could enhance the tumor radiosensitivity through inhibitiong the expression of survivin.
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nges in standard square field.
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Purpose: To understand the influence to depth doses and peripheral doses by Enhanced Dynamic Wedge and physical wedge.Methods: The depth doses and peripheral doses were measurement for open field and Enhanced Dynamic Wedge field as well as physical wedge.Results: ⑴ depth doses and peripheral doses for Enhanced Dynamic Wedge fields was very similar to those for open fields ⑵ depth doses and peripheral doses for physical wedge fields was large than those for open fields. Conclusion: depth doses measured for open fields can also be used for Enhanced Dynamic Wedge fields dose calculation. Wedge depth dose must be used in the physical wedge fields dose calculation. It should be pay attend to peripheral doses for physical wedge fields in the clinic.
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Purpose: To analyses the variation regularity of output factor of lead block fields for high energy electron beam of Varian 2300 C/D linear accelerator. Methods: Output factors of lead block fields were measured for four standard applicators under various electron beam energy. Results: The variations of output factor with field side or with applicators size were no obvious regularity Output factor of lead block fields was related to standard applicators size and lead block fields side Output factor of lead block fields was related to electron beam energy. Conclusion: Electron beam energy, standard applicator size and lead block fields side had a obvious influence upon output factor. The accurate measurement should be performed for use electron beam energy in the clinic.
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Objective To compare the accuracy of output factor calculation for rectangular inserts of electron beams by using three kinds of algorisms: square root, one dimensional formula and area periphery ration. Methods The differences between the values of output factor calculated by these three algorithms mentioned above and the results measured by ionization chamber for seven rectangular inserts were compared. Results When beam energy was fixed, the difference between calculated and measured output factors was larger for area periphery ration algorithm than that of the square root or one dimensional formula algorithms. The electron cone size, beam energy and rectangular inserts size all had some effect on the value of output factor calculated by the three algorithms. Conclusions The area periphery ration algorithm is not recommended for clinical use because of its great deviation. One dimensional formula and square root algorisms possess a good accuracy. One dimensional formula is superior to square root algorithm, but square root algorithm is more practical for clinical use.