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Biomedical subjects

A Akanuma

Publications and source records attributed to A Akanuma.

At least 55 records · Page 3Linked to original sources
PubMed1977

High-dose rate intracavitary radiation therapy for advanced head and neck tumors.

Fifty-seven treatments were performed on 27 head and neck pateints with recurrent or residual tumors on a high dose rate, remote controlled afterloading unit: There were 16 cases of maxillary sinus tumors, 6 epipharynx, 3 alveolar ridge, 1 hard palate and 1 floor of mouth. All patients have been followed up more than 2 years except one. Five patients are alive without local recurrence for more than 2 years. In 13 patients local tumors disappeared once and normal mucosa covered the tumor sites. Two patients died from local bleeding. In six patients this method failed to destroy tumors. Our prupose was palliative local control: therefore, in two-thirds of cases treated we were successful with this easy method of nonfractionated acute intracavitary radiation. This result is favorable, considering that all cases treated here were failures following full dose external radiation, although the treatment had to be repeated more than twice in 15 cases. Relief of symptoms is excellent when this therapy is used.

Alveolar Process↗
PubMed1976

Growth retardation in normal and malignant tissues.

A similiarity is found in the regression and regrowth curves of normal and malignant tissues after radiation treatments. The similarity implies that even in malignant tissues there is the practical, at least, limitation of tumor growth as in a normal organ, which is due to growth rate retardation. The retardation is considered to be the result from homologous inhibition of tumor cells. A tumor has its own growth rate which varies according to its total cell number and its environment. Approximately six months old skin metastases from breast carcinoma are still growing but are very close to the asymptote size which appears to be about 1000 cubic millimeters.

Animals↗
PubMedDate not supplied

Effect of human granulocyte colony-stimulating factor on neutropenia induced by radiotherapy and chemotherapy.

This study was designed to test the effect of human granulocyte colony-stimulating factor (hG-CSF) in patients at risk for neutropenia caused by radiotherapy plus chemotherapy. Twelve patients with advanced esophageal tumor were treated after operation with 'sandwich' radiochemotherapy (successive treatment with chemotherapy-radiotherapy-chemotherapy). hG-CSF was given subcutaneously at a dose of 2 micrograms/kg/day for 3-5 days after the white blood cell counts decreased to less than 3,000/mm3. Neutrophil counts significantly recovered to normal levels within 5 days in all patients treated with hG-CSF. No significant changes in the lymphocyte, platelet and red blood cell counts were shown. No side effects were observed. These results indicate that hG-CSF is a useful tool for the treatment of neutropenia induced by radiotherapy and chemotherapy.

Aged↗
PubMedDate not supplied

Multi-institutional clinical studies on hyperthermia combined with radiotherapy or chemotherapy in advanced cancer of deep-seated organs.

Multi-institutional studies on clinical hyperthermia of deep-seated tumours were undertaken using 8 MHz radiofrequency capacitive heating devices (Thermotron RF-8) at seven institutions. Each institute was designated to treat specific organs. This paper contains the accumulations of the results obtained at different institutions charged for different tumours. Deep-seated tumours in the lung, stomach, pancreas, liver, urinary bladder and rectum were treated. A total of 177 cases examined from January 1985 to December 1988 included 96 cases (54%) treated with radiotherapy plus hyperthermia, among which 14 cases were pre-operative. Of 177 cases, 81 (46%) were treated with chemotherapy plus hyperthermia. Complete response (CR) and partial response (PR) were obtained in 80% of the cases with lung cancer, 39% with stomach cancer, 56% with liver cancer, 35% with pancreas cancer, 71% with urinary bladder cancer, 100% with primary rectal cancer, and 47% with recurrent rectal cancer. Thermometry was performed using two techniques; one is direct measurement of intratumour temperature in lung and liver cancers, the other is indirect measurement of intracavitary temperature for stomach, pancreas, urinary bladder and rectal cancers. Intratumour temperatures were measured in 30 of the 43 tumours of the lung and liver. The maximum tumour temperature was greater than 42 degrees C in 23 (77%) of the 30 tumours. Intracavitary temperatures were measured in 133 (99%) of the 134 tumours of stomach, pancreas, urinary bladder and rectum. An intracavitary temperature greater than 42 degrees C was obtained in 98 (73.7%) of the 133 tumours. The contribution of hyperthermia in improving the quality of life of patients under terminal care was also investigated. It was indicated that hyperthermia was one of the most effective treatment techniques for advanced or inoperable cases. In this study local control rate (LCR) was mainly discussed because the period of follow-up was only 3 years. Side-effects were observed in 37 cases (21%); main side-effects were fatty induration, pain during treatment and burn. However, no side-effects were severe enough to interrupt therapy.

Adult↗
PubMedDate not supplied

Dosimetry of radiation scattered to thyroid gland from prophylactic cranial irradiation for childhood leukemia.

Dosimetry of radiation scattered to the thyroid gland was performed in 17 children (9 boys, 8 girls) who were treated for acute lymphoblastic leukemia and received cranial irradiation for prophylaxis against central nervous system leukemia at a median age of 4 years and 2 months (range, 1 year and 1 month to 14 years). The absorbed dose to the thyroid gland in these children ranged from 0.7% to 7.3% of the dose delivered to the cranium. Thus the total dose to the thyroid gland ranged from 0.13 to 1.32 Gy by the end of the entire course of cranial irradiation. Doses tended to be larger in younger children, but the radiation source also had a large influence on the dose to the thyroid gland; that is, the absorbed dose to the thyroid gland with delivery by linear accelerator was smaller than that by cobalt irradiation. Long-term survivors treated with cranial irradiation for acute leukemia during childhood should be followed for the possible development of thyroid diseases, including malignant tumors, for a long period.

Adolescent↗
PubMedDate not supplied

Radiation therapy of intracranial germ cell tumors with radiosensitivity assessment.

Fifty patients with pineal and/or suprasellar tumors were treated in the Department of Radiology, University of Tokyo, from 1975 to 1988. Histological diagnosis was obtained in 28 cases, whereas 22 patients were irradiated without pathological verification. Of the 28 patients with histological diagnosis, 11 had germinomas, 13 non-germinoma germ cell tumors, including nine teratomas, two choriocarcinomas and two embryonal carcinomas, two pineocytomas and two pineoblastomas. The treatment protocol since 1981 has been that, after 20 Gy is given with a local irradiation field, if tumor regression is marked and germinoma is highly suspected, whole brain or whole CNS irradiation is performed subsequently; otherwise, surgical intervention is performed followed by systemic chemotherapy plus radiation therapy. The five-year survival rates of histologically proven germinomas, histologically proven non-germinoma germ cell tumors, and clinically suspected germinomas by means of the above-mentioned method as well as tumor marker status were 73%, 28%, and 83%, respectively. The overall five-year survival rate was 61.3%. A statistically significant difference was found between the survival rates for the 11 cases with histologically proven germinoma and the 13 cases with non-germinoma germ cell tumors, although there was no significant difference between the survival rates for the histologically proven germinomas and the clinically suspected germinomas. Therefore radiation therapy is an effective treatment method for the management of intracranial germ cell tumors.

Adolescent↗
PubMedDate not supplied

A dose distribution evaluation utilizing megavoltage CT imaging system.

An isodose distribution (collision kinetic energy distribution) was acquired using a megavoltage CT imaging system. Direct comparison of dose distributions has become important for verification in innovative treatment techniques. Three-dimensional implementation of this system is considered highly feasible.

Humans↗
PubMedDate not supplied

Radiation therapy of carcinoma of the oropharynx.

Forty consecutive cases of carcinoma of the oropharynx were treated by irradiation from 1973 through 1987. The overall five-year survival rate calculated by the Kaplan-Meier method was 21%. Data were also analyzed retrospectively to investigate the factors associated with prognosis. The following results were obtained. (1) The results of re-irradiation as salvage treatment were poor. (2) Irradiation to neck lymph node metastases was not particularly effective, especially under 50 Gy. (3) Stage T2(-4) primary tumors were difficult to control with irradiation of 50 Gy.

Adult↗
PubMedDate not supplied

Radiation therapy for primary non-Hodgkin's lymphoma of the head and neck in stages I and II.

From January 1975 through December 1986, 58 previously untreated patients with primary non-Hodgkin's lymphoma of the head and neck in stages I and II were treated at our department. Thirty-seven patients were classified as stage I and 21 as stage II. Complete local remission was obtained in all cases. The 5-year survival rates were 68% and 79% in stages I and II, respectively. The 5-year survival rates according to site of origin were as follows: Waldeyer's ring 77% and neck lymph node 63%. The 5-year survival rates according to the histological classification of the Working Formulation were 73% intermediate grade malignancy and 63% for high grade malignancy. Chemotherapy combined with radiotherapy was essential, especially for cases in stage II. The 5-year survival rate was 100% for patients with chemotherapy and 71% without chemotherapy. The relapse-free 5-year survival rate was 67% with chemotherapy and 36% without chemotherapy. Most first failures were due to the development of generalized disease and the 5-year survival rate after salvage was 44%.

Adolescent↗
PubMedDate not supplied

Carcinoma of the maxillary sinus: the role of radiotherapy.

From 1975 to 1986, 75 M0 patients with squamous cell carcinoma of the maxillary sinus were treated at the Department of Radiology, Tokyo University Hospital. The overall 5-year survival rate calculated with the Kaplan-Meier method was 24%. During the period of the study, the method of treatment used in our hospital changed. From 1975 to 1979 (the first period), the treatment of choice was low-dose irradiation and frequent necrotomy. From 1980 to 1982 (the second period), more extensive surgery was performed and 50 to 60 Gy of irradiation was given. The 5-year survival in the first period was 20%, that in the second 14%. From 1983 to 1986 (the third period), trimodal therapy (surgery + radiation + intra-arterial infusion) was introduced and 5-year survival was improved to 50%. Intra-arterial cisplatinum infusion and treatment planning using CT scans were especially useful in improving survival.

Adult↗
PubMedDate not supplied

An integrated radiotherapy treatment system and its clinical application.

A new total system for radiation therapy installed in our department consists of a linear accelerator unit with microcomputer-controlled multileaf collimators, along with a CT scanner installed in the same treatment room. Also included are a digitally controlled communal couch, a minicomputer, and a system of treatment planning devices. We have developed various kinds of external radiation treatment planning techniques (including dynamic ones) with this system on the basis of the concept of dose corresponding technique. A reference point setup method is needed to maintain a unified coordinate system through each step of the treatment procedure, and, as developed by us, permits a volume-oriented setup. This system has been evaluated for accuracy in a variety of clinical setups. A true three-dimensional dose calculation algorithm is required for treatment planning associated with multileaf collimator treatments in order to realize the potential accuracy of such a system.

Computer Simulation↗