A proton therapy system in Nagoya Proton Therapy Center.

The purpose of this paper is to describe an outline of a proton therapy system in Nagoya Proton Therapy Center (NPTC). The NPTC has a synchrotron with a linac injector and three treatment rooms: two rooms are equipped with a gantry and the other one is equipped with a fixed horizontal beamline. One gantry treatment room has a pencil beam scanning treatment delivery nozzle.

A patient-specific aperture system with an energy absorber for spot scanning proton beams: Verification for clinical application.

Purpose: In the authors' proton therapy system, the patient-specific aperture can be attached to the nozzle of spot scanning beams to shape an irradiation field and reduce lateral fall-off. The authors herein verified this system for clinical application.

Methods: The authors prepared four types of patient-specific aperture systems equipped with an energy absorber to irradiate shallow regions less than 4 g/cm(2).

[Analysis of radioactivation induced by high-energy X-rays in medical linear accelerators -estimation of short-lived radioactivated nuclides-].

In medical linear accelerators, radioactivation is induced on the target and neighborhood parts by photoneutrons accompanying a photo-nuclear reaction and leading to higher acceleration energy. We measured the residual radiation from the radioactivated materials according to the time, and tried to identify radioactivated nuclides and their relative quantities by means of measurement results. It was presumed that the main source of residual radiations was the Target, Flattening filter and Primary collimator in the linac head.

[Analysis of photonuclear activation effect of high-energy medical linear accelerators--measurement of spatial dose distribution and temporal decay curve, and assessment of personnel dosimetry].

The characteristics of activation after high-energy X-rays have been generated by medical linear accelerators were measured using an ionization chamber. Radiation doses increased with rising X-ray energy, based on 10 MV, 15 MV, and 18 MVX-ray measurements. When the total irradiation dose was changed, radiation dose increased with total irradiation dose.