| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
|
|---|
| Research Abstract |
1. Clinical research
(1) The postoperative irradiation was effective for subclinical disease or microscopic tumor of the head and neck, uterus, lung, and rectum. The amount of residual tumors was strongly related to control rate. (2) The effect of preoperative 20Gy dose for rectal cancer was significantly related to P21 and apoptosis rather than histologic differentiation. (3) The control rate for small-sized brain metastases by 30Gy dose was significantly not related to central necrosis of MRI and metastatic size, but histopathology. The central necrosis was more abounding for pulmonary adenocarcinoma than breast cancer, and it appeared >4 mm of metastasis with rapid growth rate. Necrotic tumors containing hypoxic cells were considered to be radioresistant, but they histologically have fewer cell number.
2.Basic research
(1) Tumor cell number and radiation effect strongly correlated in microscopic tumor, but it became radioresistant after 10^5 cells. It was considered the appearance of hypoxic cells, because of the enhancement by hypoxic radiosensitizer. We observed rapid tumor growth in the microscopic phase. In comparison with macroscopic tumors, RBE and dose rate effect was not different. (2) In the experiment of spontaneous lung metastases of Lewis lung cancer, the relationship between hypoxic cell, proliferation capability, blood vessel density, apoptosis and tumor cell number is studying using various sized-microscopic tumors. (3) Immunohistologic study using 50-300mm?3 sized tumors showed the microscopic tumors was histologically no difference from the macroscopic tumors, but the amount of hypoxic cells or necroses depended on tumor size and tumor bed.
3.Conclusion
In the microscopic tumors or metastases, the presence of hypoxic cells and its modifications are still important in radiotherapy.
|
