Radiation Oncology

Introduction
Radiation therapy (RT) plays an essential role in the care of patients with cancer. It is used as curative treatment for many patients with malignant disease, as integrated therapy with chemotherapy and surgery, and as palliative treatment for those in whom curative treatment is not an option. The dose of radiation delivered to the tumor must be as high as possible, while being as low as possible to surrounding normal tissues.
The focus of The Radiation Oncology Division is to develop, evaluate and expand the role of RT in cancer treatment. Establishing optimal irradiation technique, including proton treatment, is also an important goal of the division.

Routine Activities　
The Radiation Oncology Division includes five consultant physicians, six radiation technologists and two medical physicists. Treatment has been mostly based on three-dimensional planning with isodose distributions, performed by RT-dedicated helical scanning CT, to conform the dose to the tumor. More than 800 new patients were treated annually, and more than 15 clinical trials that involve RT as a sole or a combined treatment modality, for various cancers are ongoing.
The conventional (photon-electron) treatment division is equipped with three treatment machines (a Microtron with 2 gantries, a linear accelerator and a high dose rate brachytherapy unit), a CT-simulator, three treatment planning computer workstations, and many other devices. The proton treatment division, the first such hospital-based treatment facility in Japan, is equipped with a cyclotron capable of generating a 235 MeV proton beam. The proton beam is delivered to three treatment rooms (two isocentrically rotational gantries and one fixed horizontal beam line). In this year, the system was approved as a imedical equipmenti from the Japanese Government. Regular maintenance and calibration of all the division equipment is an important activity whose aim is the continual safe and accurate delivery of RT.

New Developments
1. Proton therapy was initiated in Nov. 1998 at our hospital. Proton therapy was approved as a ihighly advanced medical technologyi from the Japanese Government in July 2001. It means that the cost of the treatment can be charged to the patient, and is partly covered by social insurance. New clinical trials employing proton therapy for nasopharyngeal cancer, maxillary sinus cancer, other head & neck cancer, and prostate cancer were initiated in 2001.
2. In our proton therapy, respiration-gated irradiation technique is routinely used in the treatment of body trunk tumors. Respiration-related target motion can be evaluated by using the newly developed real-time digital radiography system and respiration-gated irradiation system. We have analyzed the targeting accuracy during respiration-gating, and also developed the model of 4-dimensional treatment planning.
3. New protocol of combined short course accelerated RT and gemcitabine for unresectable locally advanced pancreatic cancer was proposed from the division and started the clinical trial.
4. Radiotherapy Quality assurance (QA) survey of the clinical trials was initiated in both Japan Radiation Oncology Group (JROG) and Japan Clinical Oncology Group (JCOG).

T. OGINO

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