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Biomedical subjects

Y Akine

Publications and source records attributed to Y Akine.

At least 55 records · Page 3Linked to original sources
PubMed1990

Dose equivalence for high-dose-rate to low-dose-rate intracavitary irradiation in the treatment of cancer of the uterine cervix.

By comparing the incidence of major radiation injury, we estimated doses clinically equivalent for high-dose-rate (HDR) to conventional low-dose-rate (LDR) intracavitary irradiation in patients with Stages IIb and IIIb cancer of the uterine cervix. We reviewed a total of 300 patients who were treated with external beam therapy to the pelvis (50 Gy in 5 weeks) followed either by low-dose-rate (253 patients) or high-dose-rate (47 patients) intracavitary treatment. The high-dose-rate intracavitary treatment was given 5 Gy per session to point A, 4 fractions in 2 weeks, with a total dose of 20 Gy. The low-dose-rate treatment was given with one or two application(s) delivering 11-52 Gy to the point A. The local control rates were similar in both groups. The incidence of major radiation injury requiring surgical intervention were 5.1% (13/253) and 4.3% (2/47) for low-dose-rate and high-dose-rate groups, respectively. The 4.3% incidence corresponded to 29.8 Gy with low-dose-rate irradiation, thus, it was concluded that the clinically equivalent dose for high-dose-rate irradiation was approximately 2/3 (20/29.8) of the dose used in low-dose-rate therapy.

Aged↗
PubMed1990

Carcinoma of the uterine cervix treated by irradiation alone. Results of treatment at the National Cancer Center, Tokyo.

Six hundred and twelve patients with previously untreated invasive carcinoma of the uterine cervix were treated by irradiation alone at the National Cancer Hospital from 1972 to 1983. The number of patients was 7, 39, 43, 127, 15, 319, 28 and 34 in stages IA, IB, IIA, IIB, IIIA, IIIB, IVA and IVB respectively. Low-dose-rate intracavitary irradiation with or without external irradiation was used in 383 patients, high-dose-rate intracavitary irradiation with or without external irradiation in 130, external irradiation alone in 98, and external irradiation combined with radon-222 seed implantation in one patient. Five-year-survival rates were 85, 65, 57, 41, 14 11% for stages IB, IIA, IIB, IIIB, IVA, and IVB respectively. The rate of complications was rather high in the present series, and so we have been investigating whether it is possible to reduce the dose. Low-dose-rate intracavitary irradiation has been replaced by high-dose-rate irradiation by using a remotely controlled afterloading system.

Adult↗
PubMed1990

[Control of aftereffects due to intraoperative radiotherapy].

In cases of treating a pancreatic cancer, an aneurysm and thrombus of the abdominal aorta, necrosis of the vertebral body, and damage to the peripheral nerves can be caused by intraoperative radiotherapy (IORT). These aftereffects have been observed in tests conducted in experimental animal reported by Colorado State University. Similarly, our clinical experiences have led us to set safety guidelines to prevent damage due to IORT. The safety level of a radiation dose for IORT alone is limited to 30 Gy, and for IORT combined with external beam radiotherapy, from 20 Gy (IORT) plus 50 Gy (EBRT). Using these parameters, among 58 cases of a pancreatic tumor treated by IORT, only one case subsequently developed a pseudoaneurysm at the stump of splenic artery.

Adult↗
PubMed1990

Radiation effect of gadolinium-neutron capture reactions on the survival of Chinese hamster cells.

In gadolinium-neutron capture reactions, prompt gamma rays with an energy spectrum of up to 7 MeV, X-rays and electrons are released. We measured the effect of radiation as a result of capture reactions on cultured Chinese hamster cells. Cells in the medium containing 5000 ppm gadolinium were exposed to thermal neutrons from a nuclear reactor. The survival curve for those cells exhibited a shoulder in the low neutron fluence region. The survival curve for cells exposed to thermal neutrons in the absence of gadolinium was a simple exponential function. To obtain 10% survival levels, 5.4 x 10(12) neutrons/cm2 were required for cells irradiated in the absence of gadolinium, and 1.55 x 10(12) neutrons/cm2 for those irradiated in the presence of gadolinium. The therapeutic ratio in gadolinium-neutron capture therapy depends on the difference in 157Gd concentrations between the tumor and normal tissues. Thus, our current effort has been to develop a method of selectively delivering 157Gd to tumors.

Animals↗
PubMed1989

The second carcinoma of the anterior two-thirds of the tongue after successful radiotherapy to the tongue.

Of 221 patients with carcinoma of the mobile tongue treated by radiotherapy, 129 survived without local recurrence for 5 years or longer after initial treatment. These 129 patients were studied to determine the incidence of second carcinoma of the tongue which first appeared more than 5 years after the initial treatment. Modalities of irradiation were radium needle implantation and intraoral electron irradiation for 105 and 24 patients, respectively. Twenty-two of the patients were found to have second carcinoma of the tongue. The incidence appeared to increase as the amount of radiation given increased. No obvious relationships were observed between the second carcinoma and modality of irradiation, T classification, presence of leukoplakia before the treatment, degree of histological differentiation, or degree of radiation injury. There were moderate to severe radiation injuries in 50% of the patients treated by radium needle implantation. It is likely that most of the second carcinomas of the tongue represent the late appearance of one of the multicentric foci of the tumor, not a regrowth of the residual primary tumor. In spite of the rather high rate of second carcinoma of the tongue, radiotherapy remains an excellent modality of treatment when patients are properly selected.

Brachytherapy↗
PubMed1989

[Basic study for measurement of radiation damage of DNA using a flow cytometry].

Radiation damage of DNA in HeLa cells was measured according to a method reported by Milner, et al. Cells were suspended in lysis buffer to obtain nucleoid. They were stained with ethidium bromide immediately before the measurement by using a system of flow cytometry. The mean position of channels for forward scatters increased at first and decreased thereafter as the concentration of ethidium bromide increased. The biphasic response disappeared with irradiation given to the cells. When the concentration of ethidium bromide was constant, the mean position of channels for forward scatters increased as the dose of irradiation increased. It might be possible to use the method in predicting the response of a tumor to irradiation in the clinical practice.

Cell Nucleus↗
PubMed1988

High-dose-rate intracavitary irradiation in the treatment of carcinoma of the uterine cervix: early experience with 84 patients.

Eighty-four patients with previously untreated invasive carcinoma of the uterine cervix were treated by high-dose-rate intracavitary irradiation using a remotely controlled afterloading system (Ralstron) with or without external irradiation at the National Cancer Center Hospital, Tokyo, between 1977 and 1981. Survival rates and local control rates were comparable to those for 372 patients treated by low-dose-rate intracavitary irradiation with or without external irradiation from 1972 to 1981 at the hospital. The incidence of major complications was 5.1 and 2.4% for the patients treated by low-dose-rate intracavitary irradiation and by high-dose-rate irradiation, respectively. The results are comparable to those reported by other institutions. We have abandoned the conventional low-dose-rate intracavitary irradiation with the impression that the high-dose-rate remotely controlled afterloading system is a good alternative to the conventional one.

Adult↗
PubMed1988

Hyperthermic therapy of deep seated tumors: comparison of the heating efficiencies of an annular array applicator and a capacitively coupled radiofrequency system.

Among 82 cases of deep seated tumors treated by hyperthermia with an annular array applicator (AA) and/or a capacitively coupled 8 mHz system (CCS) combined with radiation therapy, 13 cases were treated by both devices. The efficiencies of tumor heating were compared in terms of the time required to attain 42 degrees C, the duration of heating time and the thermal dose as determined by a biological iso-effect formula for equivalent minutes at 42.5 degrees C. Temperature profiles and percent of temperature levels greater than 42 degrees C were better in the cases treated by the AA, but higher thermal doses were obtained with the CCS because longer treatment times were tolerated with the CCS than with the AA. Methods are necessary to prevent excess elevation of body temperature in the case of the AA, and to reduce superficial pain where the applicators contact the skin in the case of the CCS.

Adult↗
PubMed1988

Radiation therapy for advanced gastric cancer.

A retrospective study of 75 patients with advanced inoperable gastric cancers, referred to the National Cancer Center Hospital between 1962 and 1982, was performed. According to the Borrmann classification based on X ray findings, Type 1 was found in 3 patients, Type 2 in 5, Type 3 in 40, and Type 4 in 15. Twelve patients could not be classified. The histological type was papillary adenocarcinoma in 7 patients, tubular adenocarcinoma in 23, mucinous carcinoma in 6, poorly differentiated adenocarcinoma in 14, signet ring cell carcinoma in 12 and others in 13. The site of remote metastasis in 19 patients was Virchow's lymph node in 8 patients, Douglas pouch in 3, liver and lung in 2 each and others in 4. All patients were treated by a either telecobalt 60 unit or a linear accelerator using 6 Mv photon and the total dose to primary lesion was 4000 cGy in 5 weeks to 7000 cGy in 8-9 weeks. Complete response (CR) was achieved in 6 patients or 8.0%, partial response (PR) in 46 or 61.3%, and no change (NC) in 23 or 30.7%. The response rate based on the sum of CR and PR was about 70%. The 50% survival period in months was 26.5, 7.3, and 3.2, respectively for patients with CR, PR, and NC. For the response of advanced gastric cancer to chemotherapy in the National Cancer Center Hospital, the combined use of UFT and Mitomycin C gave the highest rate, 46%. As for as local response is concerned, the response rate to radiation was 70%, a better result than that of chemotherapy alone.

Adenocarcinoma↗
PubMed1988

[Hyperthermia in bone and soft tissue tumors].

Local response of hyperthermia for soft tissue and bone tumors was investigated. Ten tumors were superficial tumors and 16 were deep seated tumors; 9 tumors were malignant fibrous histiocytoma, 5 were liposarcoma, 4 were neurogenic and 3 were myogenic sarcoma. The other five tumors were an angiosarcoma, a malignant mesenchymoma, an Ewing's sarcoma, a chordoma and an osteosarcoma. Some 23 tumors were heated in combination with radiation therapy, and 3 were combined with arterial infusion of ADR. Four of 10 superficial tumors disappeared (CR), and, 2 of 10 signified PR. Only one of 16 deep seated tumors showed CR, 3 were PR and 12 showed no response. But 4 of 12 tumors without regression in tumor volume indicated coagulation necrosis owing to histological examinations, and 5 of 12 were regarded as the same response from hypodensity area with CT examination after hyperthermia. Local response rate of of superficial tumors was 60% and that of deep-seated tumors was 81.4%.

Bone Neoplasms↗
PubMed1987

[Results of radiation therapy of recurrent gastric cancer].

Thirty-six cases with recurrent gastric carcinoma were treated with radiation at the National Cancer Center Hospital between 1962 and 1983. There are 17 local, 12 peritoneal and 7 lymph node recurrences, and the 50% survival months were 7.2, 5.1, and 3.8 months respectively. The survival rates of these patients were 17% at one year, 5% at two year, and 3% at three year. As a conclusion, it was suggested that combined radiation therapy with some anticancer drugs should be effective procedure to prolong the life of patients with recurrent gastric carcinoma.

Adenocarcinoma↗
PubMed1986

Carcinoma of the uterine cervix treated with external irradiation alone.

One hundred and four out of 2701 patients with carcinoma of the uterine cervix were treated with a curative intent by external irradiation alone at the National Cancer Center Hospital from 1962 to 1979. All patients were judged inappropriate for the combined treatment of intracavitary and external irradiation, which was the treatment of choice for patients with advanced carcinoma of the uterine cervix in the hospital. The 5-year survival rate was 17% overall and 36, 17, and 5% for patients with Stage II, III, and IV disease, respectively. The local control rate was 20%, at 2 years, for all patients. Major complications were observed in five patients. There were no major complications in patients given a total dose of less than 115 in the Time Dose Fractionation factor (TDF). External irradiation combined with interstitial irradiation and/or hyperthermia is being considered to improve the results.

Adult↗
PubMed1986

Radiotherapy of brain metastases.

The effect of radiotherapy in 254 cases of brain metastases, treated between 1977 and 1984, were studied. The cases included 141 of lung cancer, 28 of mammary cancer, and 85 of other primary sites. The percentages of patients with improvement in clinical symptoms were 8, 39, and 66, respectively. These were groups of patients irradiated with less than 30 Gy, 30 Gy to 50 Gy, and more than 50 Gy. The 50% survival periods from the start of irradiation for the last group were as follows: for radiotherapy only, 4.1 months, radiotherapy and surgery, 4.2 months, radiotherapy and chemotherapy combined, 6.9 months, radiotherapy, surgery and chemotherapy combined, 12.1 months. The intervals between the initial diagnosis and brain metastases were different in lung cancer and mammary cancer, but the prognosis after brain metastases showed little difference between them.

Brain Neoplasms↗