Document Type : Conference Proceedings
Departments of Physics, Faculty of Science, Urmia University, The west azaarbayjan, Iran
Introduction: Cancer is, in essence, a genetic disease and is the second leading cause of death globally. Fortunately, many common types of cancer are treatable if detected early and of course there are many medications and treatments available today. Among the new methods to treat cancer, radiotherapy seems to be hopeful in patients with malignancies. This work investigates the strontium beta irradiation (90Sr) dose response on the clonogenicity of Animal blood cancer cell row K562. Scope of this work is the survey of cells survival for three time periods of irradiations and calculating absorbed doses of cancer cells by Monte Carlo simulation.
Materials and Methods: The K562 cells were cultured and irradiated with β-particle emitted from 90Sr, daily 30 minutes, 1 hour and 2 hours for 3 days. Cells survival was evaluated by three methods of MTT assay, cell visual survey and DNA electrophoresis after irradiation. To compare the results of cells survival after irradiation, determination of absorbed dose of cancer cells is necessary. But, the short ranges of the emitted beta particles and the associated large dose gradients make experimental measurements particularly difficult. In this circumstance, we have motivated by using of Monte Carlo simulation techniques. To calculate absorbed doses of cancer cells via Monte Carlo, the problem was simulated with MCNP code. Of course, to verify results of simulation with results experimental, we used a Geiger Muller counter and estimated a Scaling Factor.
Results: cell visual survey presents photomicrographs of blood cancer cells sections indicating the number of the survive cells after irradiations. Survival percent were obtained for three time periods of irradiations in MTT assay. The survival of cells was described as a function of dose and these absorbed doses were determined using MCNPX code. Finally, to recognize that The cells death was been only due to the destruction of the cell membrane, or the irradiation affect DNA and break it, we did DNA electrophoresis assay.
Conclusion: Cell visual survey indicates the positive effectiveness of beta particles on cancer cells. Also, Comparing the survival curves, that hypersensitivity component and dose rate effects are small or absent in high LET, we estimated α component. Eventually, checking the DNA electrophoresis, we understood that in very low-dose- rate up to 2.213±0.0015cGy, cells death Arises from destructing the cell membrane but form 2.213±0.0015 cGy to top, ray begin to effect on DNA.