Rotational output and beam quality evaluations for helical tomotherapy with use of a third-party quality assurance tool.

Our aim was to determine whether a third-party quality assurance (QA) tool was suitable for the measurement of rotational output and beam quality in place of on-board detector signals. A Rotational Therapy Phantom 507 (507 Phantom) was used as a QA tool. The rotational output constancy (ROC507) and the beam quality index ([Formula: see text]) were evaluated by analysis of signals from an ion chamber inserted into the 507 Phantom. On-board detector signals were obtained for comparisons with the data from the 507 Phantom. The rotational output (ROC(detector)) and beam quality (corrected cone ratio; CCR) were determined by analysis of on-board detector signals that were generated by irradiation. The tissue phantom ratio at depth 20 and 10 cm (TPR20, 10) was measured with a Farmer-type ionization chamber inserted in a plastic-slab phantom. For rotational output measurement, the correlation coefficient between ROC507 and ROC(detector) values was 0.68 (p < 0.001). ROC507 and ROC(detector) values showed a reduced coefficient of variation after magnetron replacement, which was done during the measurement period. In addition, ROC507 values were reduced significantly along with ROC(detector) values after target replacement (p < 0.001). Regarding the beam quality index, [Formula: see text] showed a change similar to CCR and an increase similar to TPR20, 10 after magnetron/target replacement. This QA tool could check for daily rotational output and detect changes in rotational output and beam quality caused by magnetron or target failure as well as when on-board detector signals were used. Without needing a tomotherapy quality assurance license, we could effectively and quantitatively estimate the rotational output and beam quality at a low cost.

Influence of ligand flexibility on the electronic structure of oxidized Ni(III)-phenoxide complexes.

One-electron-oxidized Ni(III)-phenoxide complexes with salen-type ligands, [Ni(salen)py2](2+) ([1(en)-py](2+)) and [Ni(1,2-salcn)py2](2+) ([1(cn)-py](2+)), with a five-membered chelate dinitrogen backbone and [Ni(salpn)py2](2+) ([2(pn)-py](2+)), with a six-membered chelate backbone, have been characterized with a combination of experimental and theoretical methods. The five-membered chelate complexes [1(en)-py](2+) and [1(cn)-py](2+) were assigned as Ni(III)-phenoxyl radical species, while the six-membered chelate complex [2(pn)-py](2+) was concluded to be a Ni(II)-bis(phenoxyl radical) species with metal-centered reduction in the course of the one-electron oxidation of the Ni(III)-phenoxide complex [2(pn)-py](+). Thus, the oxidation state of the one-electron-oxidized Ni(III) salen-type complexes depends on the chelate ring size of the dinitrogen backbone.

[Three successful case reports of advanced gastric cancer with chemotherapy].

We report three successful cases with continuous systemic chemotherapy for advanced gastric cancer. Case 1: A 67-year-old male with gastric cancer. Abdominal CT showed the invasion in the pancreas and as a result, continuous systemic infusion of low-dose cisplatin (CDDP 20 mg/day) and 5-fluorouracil (5-FU 1,000 mg/day) was performed. This infusion chemotherapy, CDDP and 5-FU, was continued for 5 days and discontinued for 25 days. Three months after the chemotherapy, the main tumor was remarkably reduced (downstaging was obtained), and consequently, total gastrectomy was performed. Case 2: A 78-year-old male with gastric cancer and hepatic multiple metastases. Abdominal CT scan before operation did not reveal the hepatic metastasis. In the operation for distal gastrectomy, we found multiple metastases on the surface of the liver. Continuous systemic infusion of low-dose CDDP (20 mg/day) and 5-FU (1,000 mg/day) was performed. This infusion chemotherapy, CDDP and 5-FU, was continued for 5 days and discontinued for 2 days. One month after the chemotherapy, Liver metastases had almost disappeared. Case 3: A 73-year-old male had received a distal gastrectomy based on the diagnosis of gastric cancer. The tumor marker, CA19-9, immediately decreased after the operation, but had increased again. He was treated with a combination chemotherapy of TS-1 and CDDP. The treatment consisted of 4 weeks of TS-1 administration (100 mg daily) followed by a 2-week break. CDDP of 10 mg/day was infused intravenously (day 1-5). Four weeks after the infusion, CA19-9 had returned to almost normal. We conclude that the combination chemotherapy of 5-FU (or TS-1) and CDDP might be an effective treatment for advanced and metastatic gastric cancer.