Research Abstract |
Pilot study of non co-planar and conformal fast neutrons (FNs) therapy for 28 patients (35 sites ) of brain tumors was evaluated. Patients were consisted of 9 cases (9 sites) of primary brain tumor (3 sites of astrocytoma grade II,4 sites of anaplastic astrocytoma and 2 sites of glioblastoma multiform) and 19 cases (26 sites) of metastatic brain tumors (24 sites of adenocarcinoma of the lung and 2 sites of the renal cell carcinoma). FNs were irradiated through 6 daily different ports in single plane and maximum 3 planes (total 18 ports) were sued in this study and irradiated 3 fractions in a week. For primary tumors, FNs of fraction dose of 0.9 Gy (n, gamma) through total dose of 16.2 Gy (n, gamma)/18 fractions were irradiated for 4 sited and one site was irradiated by total dose of 10.8 Gy (n, gamma)/12 fractions brcause of first case of this study. Residual 4 sites of primary tumors were irradiated by combined radiotherapy with 10 MeV X rays 0f 40 Gy/16 fractions/4 weeks and FNs of 4
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.0 Gy (n, gamma)/6 fractions-10.0 Gy (n, gamma)/9 fractions brcause of large irradiated volume. For 8 sites of metastatic tumor, so-called neutron knife which means 6 ports irradiation in a day was applied. Total dose of neutron knife was 3.0 Gy (n, gamma) for initial 3 cases and 5.0 Gy (n, gamma) for later 5 cases. For 10 sites of metastatic tumor, fraction dose of 1.1-1.3 Gy (n, gamma) through total dose of 7.8 Gy (n, gamma)/6 fractions-20.0 Gy (n, gamma)/18 fractions (average of 16.1 Gy (n, gamma)/14 fractions) of FNs were irradiated. For residual 8 sites of metastatic tumors, 10 MeV X rays irradiation of 10 Gy/4 fraction-37.5 Gy/15 fractions was combined followed by boost therapy of FNs of 5.4 Gy (n, gamma)/6 fractions-13.3 Gy (n, gamma)/12 fractions. Tumor reactions at one month after the treatment were 3 sites of partial reaction (PR) and 1 site of no change (NC) in primary tumors treated by FN alone, 1 site of complete remisson (CR) and 4 of PR in primary tumors treated by combined irradiation, 1 of CR,3 of PR,2 of NC and 1 site of progressive disease (PD) in metastatic tumors treated by FN alone, 2 of CR,5 of PR 2 of NC and 1 of unknown (because of death within 1 month after treatment) in neutron knives and 4 of CR,1 of PR and 3 of unlnown in metastatic tumors treated by combined radiotherapy. One year and 2 years survival rates were 67% and 0% in primary tumors treated by FNs alone, 100% and 67% in primary tumors treated by combined irradiation, 75% and 75% in metastatic tumors treated by fast neutron alone, 40% and 0% in nutron knives and 14% and 14% in metastatic tumors treated by combined radiotherapy. In 28 patients with 35 sites, there was no definitive acute and/or late complications associated with neutron therapy. Past literatures reported unacceptable brain complications after FNs irradiation of 14.0-16.0 Gy (n, gamma) for the whole brain. In this study, 20 Gy (n, gamma) of FNs was irradiated to localized volume of the brain. Although the tumor rea Less
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