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Biomedical subjects

Y Akine

Publications and source records attributed to Y Akine.

At least 19 recordsLinked to original sources
PubMed1992

Neutron-capture therapy of murine ascites tumor with gadolinium-containing microcapsules.

Gadolinium-containing microcapsules were evaluated as an agent for gadolinium neutron-capture therapy. Mice were inoculated intraperitoneally with 10(7) Ehrlich ascites tumor cells and gadolinium microcapsules and exposed to thermal neutrons for 12 min (approximately 1.86 x 10(12) neutrons cm-2). Significantly more mice given gadolinium microcapsules than those given placebo microcapsules or control survived for 60 days and considerably longer (P < 0.0001), indicating that gadolinium neutron-capture reactions effectively suppressed the growth of ascites tumor cells in mice. The results suggest that these microcapsules are an effective gadolinium carrier for neutron-capture therapy.

Animals↗
PubMed1992

Radiotherapy for bone metastases of hepatocellular carcinoma.

Radiotherapeutic effects of 42 bone metastases in 26 hepatocellular carcinoma patients were retrospectively analyzed. Pain relief was observed in 79% of 37 bone metastases treated (29/37). Antitumor effects and improvement of paralysis were also observed in 88% (8/9) and 17% (1/6), respectively. The toxicities experienced were tolerable. Radiotherapy was an effective means of palliation in the treatment of hepatocellular carcinoma bone metastases.

Adult↗
PubMed1992

[Linac based radiosurgery; a technical report].

A method for highly dose-localized irradiation using a linear accelerator (linac) for a brain tumor has been developed. The method requires a linac, a computed tomography (CT) system, a CT simulator, and a treatment planning system for radiotherapy, with which most major radiotherapy centers are equipped. To immobilize a patient during irradiation, a custom-made device made of synthetic material which became flexible with heating was used. With the CT system and the CT simulator the target was identified and geometrical data for positioning the tumor at a point to which x-ray beams were directed (an isocenter of the linac) were obtained. By rotating a treatment couch it was made possible for the x-ray source to rotate around the isocenter on multiple planes. Dose distribution obtained with this method was compared to that of the gamma unit and found comparable. Since the method requires no invasive procedure, it appears suitable for treatment, with fractionated irradiation, of malignant tumors.

Brain Neoplasms↗
PubMed1991

Stage I-II carcinoma of the anterior two-thirds of the tongue treated with different modalities: a retrospective analysis of 244 patients.

Treatment results of 244 patients with stage I-II cancer of the mobile tongue were analyzed according to the modalities employed (implantation, surgery, cryosurgery and intraoral irradiation). Overall local control rates at three years were 90 +/- 3% for implant, 89 +/- 7% for cryosurgery, and 84 +/- 9% for surgery. Local control rates in stage II patients treated with intraoral electron irradiation, however, were only 50 +/- 13%. Five-year survival rates were 72 +/- 3% with no significant differences observed in patients with either stage I or stage II regardless of treatment modality. Sixty percent (29/48) of the patients with local recurrences were salvaged by the second treatment. Since the local control and survival achieved by these modalities were similar, with the exception of patients with stage II treated by intraoral electron irradiation, we recommend interstitial implantation with iridium, intraoral electron irradiation or surgery for patients with T1 tumors, and iridium implantation or surgery for patients with T2 tumors. For those with superficial lesions measuring 5 mm or less in thickness, cryosurgery is being offered as an alternative. The patient can choose the treatment modality taking into account his/her age, sex and profession.

Combined Modality Therapy↗
PubMed1991

Radiotherapy of T1 glottic cancer with 6 MeV X rays.

We treated 154 patients with T1 glottic carcinoma with 6 MeV X rays through 16 cm2 parallel-opposing open fields on a free set-up delivering a median dose of 67 Gy in 6 2/3 weeks. Observed and relative 5-year survival rates for all patients were 87% and 100%, respectively. The local control rate at 5 years was 89%. Of 18 patients who clinically had local recurrence, 17 were salvaged by a secondary treatment. There were no complications requiring medical or surgical attention. A tendency toward increasing local control rates with increasing total doses was observed in the range between 57.5 Gy and 72.5. No significant correlation was found between local control rates and field size, daily dose, or the technique used. A tendency toward a lower local control rate was noted for patients whose anterior commissures were grossly involved; however, it is not known if this could be attributed to the use of 6 MeV X rays. The results are comparable to those obtained with 60Co as reported in the literature. It is concluded that 6 MeV X rays on a free set-up delivering 65-70 Gy in 6 1/2-7 weeks can be used satisfactorily for the treatment of early glottic carcinoma.

Adult↗
PubMed1990

[Radiotherapy for endobronchially invading recurrence of esophageal cancer after resective surgery].

Sixty-eight patients with endobronchially invading recurrence of esophageal cancer after resective surgery were treated with radiotherapy from 1966 to 1988. The mean interval between resective surgery and diagnosis of recurrence was 11.1 months, that was significantly shortened in a3 group. The dose of radiation for recurrence ranged from 2 to 70.3 Gy, with a mean dose of 42.6 Gy. The mean survival time after treatment of recurrence was 4.9 months. The dose of radiation was found to have a positive correlation with survival time. The cause of death was bleeding in 20 patients, and respiratory failure in 36. High dose of radiation was thought to induce high incidence of bleeding. The results indicated that external beam radiotherapy with conventional fractionation was not so much effective for the recurrence.

Adult↗
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↗