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 an optimal irradiation technique, including proton treatment, is also an important goal of the Division.

　Routine Activities

　　The Radiation Oncology Division includes five consultant physicians and six technologists. A medical physicist is employed in the Division this year. Around 600 new patients were treated in 1998. 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 15 clinical trials, which 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 hospital-based treatment facility in Japan, is equipped with a cyclotron which generates 235MeV proton beam. Proton beam is delivered to three treatment rooms (two isocentrically rotational gantries and one fixed horizontal beam line). Regular maintenance and calibration of these machines is also an important project aimed at delivering RT safely and accurately.
　　Case conferences are held on Wednesday afternoons. A tele-image conference between the Radiation Oncology Division, the National Cancer Center Hospital, Tokyo, and our Division was initiated in 1995.
New Developments
1.　Proton treatment was initiated in November 1998 at our hospital. The first clinical trial of proton therapy is a pilot study for head and neck malignancies. Before initiating patient treatment, beam tests and biological experiments were carried out in 1998.
2.　Patient position verifying systems using digital imaging technology was newly developed. One uses a computed radiography system and the other a real-time digital fluoroscopic radiography system. We have applied these systems, which have been originally used for diagnostic puroposes, to radiation therapy.
3.　Intraluminal brachytherapy for portal vein tumor thrombi of hepatocellular carcinoma was established and a clinical trial initiated.

　Statistics

Number of Patients Treated Receiving Radiotherapy

	1994	1995	1996	1997	1998
New patients	458	558	593	631	616
New treatments	629	809	796	807	769
Head and neck	99	134	138	144	143
Lung, mediastinum	206	247	267	237	224
Breast	75	78	82	94	94
Gastrointestinal tract	79	128	135	150	133
Hepatobiliary and pancreatic regions	91	103	85	77	89
Gynecology	5	17	11	11	18
Urology	8	17	7	12	12
Bone and soft tissue	22	45	29	22	12
Hematology	25	34	32	46	37
Others	19	6	10	14	7
Primary site	202	297	312	352	375
Recurrent, metastatic site	315	399	367	344	311
Prophylactic purpose	112	114	117	111	84
Intraoperative RT	50	62	57	55	49
Brachytherapy	5	39	27	15	18

RT, Radiation therapy.

(T. Ogino)　

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