Efficiency of respiratory-gated delivery of synchrotron-based pulsed proton irradiation.

Significant differences exist in respiratory-gated proton beam delivery with a synchrotron-based accelerator system when compared to photon therapy with a conventional linear accelerator. Delivery of protons with a synchrotron accelerator is governed by a magnet excitation cycle pattern. Optimal synchronization of the magnet excitation cycle pattern with the respiratory motion pattern is critical to the efficiency of respiratory-gated proton delivery.

Correlation between internal fiducial tumor motion and external marker motion for liver tumors imaged with 4D-CT.

Purpose: We investigated the correlation between the motions of an external marker and internal fiducials implanted in the liver for 8 patients undergoing respiratory-based computed tomography (four-dimensional CT [4D-CT]) procedures.

Methods And Materials: The internal fiducials were gold seeds, 3 mm in length and 1.2 mm in diameter.

Correlation between the respiratory waveform measured using a respiratory sensor and 3D tumor motion in gated radiotherapy.

Purpose: The purpose of this study is to investigate the correlation between the respiratory waveform measured using a respiratory sensor and three-dimensional (3D) tumor motion.

Methods And Materials: A laser displacement sensor (LDS: KEYENCE LB-300) that measures distance using infrared light was used as the respiratory sensor. This was placed such that the focus was in an area around the patient's navel.

Modeling of daily operation in proton radiotherapy by Monte Carlo method.

A simple model for efficiency analysis of daily operation in proton radiotherapy is applied to numerical calculation with fixed time advancing. For the simplifying, man power is assumed to be enough and troubles in the equipments are ignored. To generate random numbers which become the time for adjusting the patient position and for waiting the next patient, typical probability distributions are utilized in the simulation.

[Respiration gated CT scanning for radiation treatment planning by guided respiration method].

In Proton Medical Research Center (PMRC), we have performed the respiration-gated irradiation for treating the tumor in the body trunk. In the conventional method, patients must hold their expiration during CT scanning. The phase of holding expiration is different from the end-expiration phase.

The direct measurement using an imaging plate for coincidence of radiation centre and laser position in external radiation therapy.

A new method of quality assurance has been studied to measure coincidence of the radiation centre and a patient-setup laser position on a transverse plane to the beam at the isocentre. This measurement is achieved by using an imaging plate (IP). When radiation is applied to an IP, the energy is stored as trapped electrons.