Abstract
It is reported that microplaner beams obtained from synchrotron radiations show higher radiobiological effects on tumor tissues than normal tissue. The radiobiological mechanisms are not known, but the potential those beams for cancer therapy is discussed as a novel radiotherapy.
We have obtained a microplaner beam at a beam line BL28B2 in Spring-8, JASRI, Harima, using a slit block having 20 mm width in horizontally, and ten 25 μm slits every 200 μm in 2 mm height. Here, we measured tumor growth delay as a pilot study with the beam. Ten to 6th cells of NFSa fibrosarcoma were transplanted in a leg of C3H mice 8 days before irradiation at NIRS, and shipped to JASRI few days before the beam-time. Mice were fixed on a plastic board under anesthesia, and 10 mm height area including the tumor was irradiated to the beam with 200 to 1600 Gy as the peak dose. Irradiated mice were transferred to Kitasato University in Aomori, and measured tumor volume every day. The tumor growth time to be 1000 mm3 from 200 mm3 at the day of irradiation were measured. The growth time for 800 Gy irradiated mice group was 10.5 days, and 5.5 days for unirradiated mice group. We could fine 5 days of the tumor growth delay in the case.
Together with tumor growth delay experiment, we tried to obtain biological dose distributions of the beam as apoptosis induction and DNA double strand break induction in the total irradiated area.
