Abstract
Purpose: Malignant pleural mesothelioma(MPM) is an aggressive tumor arising from serous surfaces and often related to asbestos exposure. MPM is resistant to various forms of therapy, such as radiotherapy, surgery or chemotherapy, and only slightly improve prognosis. So far, no effective therapeutics including chemotherapy or radiotherapy has been established for the disease-advanced case. The present study was carried out in order to examine the radiosensitivity of MPM cell lines by X rays and carbon-ion beams.Materials and methods: Officially distributed 6 kinds of MPM cell lines were used and irradiated with X-ray or carbon-ion beams (13keV/&mu and approximately 80keV/&mu) at the Heavy Ion Medical Accelerator in Chiba. Cell-killing effect was detected using a colony-formation assay.
Result: The relative biological effectiveness (RBE) values calculated by the D10,relative to X-ray, range from 1.25 to 1.62 for 13keV/&mu ion beam and from 2.42 to 3.15 for approximate 80keV/&mu ion beam irradiation on each cell line . Conclusion: The data of previous reports using carbon ion beams, Suzuki et al. showed that RBE values for 16 different human cell lines were about 1.06 to 1.33 for 13keV/&mu and from 2.00 to 3.01 for 77keV/&mu beam. The RBE values of 6 cell lines of MPM in this study for the carbon beams are almost consistent with that report using carbon ion beams with lower (13keV/&mu) and higher(approximate 77keV/&mu) LET values. This result suggest that high LET carbon ion irradiations are also significantly more cell killing effective for the 6 kinds of MPN cell lines.
