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Biomedical subjects

A Akanuma

Publications and source records attributed to A Akanuma.

At least 37 records · Page 2Linked to original sources
PubMed1993

Esthesioneuroblastoma. A report of seven cases.

The biologic behavior of esthesioneuroblastoma in seven patients, treated from 1978 to 1989, is reviewed. The patients were initially treated with surgical resection (2 cases), radiation alone (1 case) or a combination of radiation and surgery (4 cases). The radiation dose ranged from 30 to 62 Gy. Operations were performed via a transmaxillary approach (2 cases), lateral rhinotomy approach (3 cases) and craniofacial approach (1 case). Four of the seven patients experienced local recurrence, occurring after disease-free intervals as long as 6 years. The other three patients died of distant metastasis within one year after initial treatment. The effectiveness of radiation therapy varied, and in some patients a dose of 60 Gy was not enough to control microscopic disease. One patient developed bone marrow metastases which was fatal due to the ensuing pancytopenia. One patient developed a brain metastasis. Hyams' histopathologic staging of the tumor appeared to be related to prognosis.

Adolescent↗
PubMed1993

[Current status and future prospects of the radiation oncology treatment planning system].

Treatment planning is the most essential radiation oncology practice and has been developing owing to various technological innovations such as faster computing speed, advanced computer graphics and enormous data storage capacity. Treatment planning consists of CT data retrieval, target input, selection of treatment techniques and dose calculation, evaluation of dose distribution, and data transfer to the accelerator, each of which has been progressing quite rapidly. In particular, ongoing topics in treatment planning include multi-leaf conformation, non-coplanar technique, CT scanner dedicated to treatment planning and data transfer through LAN. Target delineation using PACS, and megavoltage verification imaging represented by portal imaging, are also useful. Higher local control rates as well as lower complication probabilities are expected with the sophisticated treatment planning system.

Forecasting↗
PubMed1989

Postradiation astrocytoma. Report of two cases.

The authors describe two cases of malignant astrocytomas associated with previous radiation therapy in childhood for intracranial germinoma and craniopharyngioma. In both patients, there was no recurrence at the primary tumor site. Because of a geometric coincidence between the tumor location and the radiation field, radiotherapy was strongly implicated as a cause of these two astrocytomas.

Adolescent↗
PubMed1989

Conservative treatment of carcinoma of the anorectal region--the role of radiation therapy.

Radiation therapy has now an increasing role in the treatment of rectal cancer. Formerly it was used for the palliation of recurrent or residual tumors, but now it is more frequently used for preoperative purposes. Preoperative radiotherapy has the following advantages. It often makes unresectable tumors resectable, prevents tumor seeding during the operation, treats the lateral involvement by the tumor, and makes resectable tumors resected more conservatively. So far we've treated 22 patients with advanced stage rectal cancer by preoperative radiotherapy. Their 3 year local control rate and survival rate was 79% and 86%, respectively, with 9% complication rate. And as for the anal cancers preoperative irradiation and more conservatively, definitive irradiation with doses more than 60 Gy are quite worthwhile both in terms of local control and complication. Both for rectal and anal cancers radiotherapy seems quite promising modality in local tumor control and the patient's quality of life. Further clinical trials are necessary.

Adult↗
PubMed1988

Factors possibly influencing the prognosis of oligodendroglioma.

Fifty-seven cases of oligodendroglioma (including eight cases of malignant oligodendroglioma) treated at the University of Tokyo Hospital between 1961 and 1985 were analyzed for factors influencing the survival rate. Factors related to a poor outcome were findings of malignancy and symptoms of dementia. Survival rate and postoperative survival period were not influenced significantly by radiation therapy, extent of resection, tumor characteristics, or ABO blood groups.

Adolescent↗
PubMed1984

[Synchronization chemoradiotherapy for malignant gliomas].

Cellular synchronization chemoradiotherapy was performed in 122 patients with glioblastoma and malignant astrocytoma (GrIII) registered between April 1977 and August 1982. The study was a non-randomized clinical phase II trial. The chemotherapeutic agents employed as synchronizers during the irradiation were VM26 (epipodophyllotoxin) and vincristine (VCR) as plant alkaloids and ACNU as a nitrosourea. Either VM26 or VCR was administered on D1, D2 and D3 at the dosage of 1 mg/kg (0.025 mg/kg-VCR) body weight. ACNU was administered on D2 and D3 at the dosage of 1 mg/kg body weight. The duration of the chemotherapy was eight to fourteen days at the initial induction stage and almost eight weeks at the maintenance stage. Thus, two synchronization arms of VM26 + ACNU and VCR + ACNU were employed. The regimen-VM 26 + ACNU + Radiation (Rad) could yield the initial induction of CR + PR-30%, NC-50%, and PG-15% in 58 cases. Long-term survival, calculated by the cumulative survival rate, was as follows: one year, 58%; two years, 42%; three years, 32%; four years, 30%, and five years, 25%. The regimen VCR + ACNU + Rad could yield the initial induction of CR + PR-28%, NC-49%, and PG-23% in 64 cases. The cumulative survival rate was calculated as follows: one year, 55%; two years, 42%; three years, 27%; four years, 22%, and five years, 22%. As a control, particularly for the survival rate, the data of the All-Japan Registry were revised to correspond to our study population. The survival rate of simple radiation cases thus revised was as follows: one year, 43%; two years, 23%; three years, 11%; four years, 7%, and five years, 5%. The comparison between VM 26 plus ACNU and VCR plus ACNU yielded a higher initial induction response of 35% for the former (vs. 28% for the latter), although it is difficult to make a judgement on the excellence of the regimen involving VM 26 plus ACNU, because this trial was clinical phase II. On the other hand, compared with the data from the All-Japan Registry, each regimen of cellular synchronization radiation therapy could achieve statistically more excellent responses both in the initial induction and the long-term survival (p less than 0.01). Thus, cellular synchronization radiation therapy is a hopeful therapeutic method for malignant glioma, with less side effects and statistically confirmed higher responses.(ABSTRACT TRUNCATED AT 400 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

[Standardized radiation treatment method for carcinoma of the uterine cervix].

Due to a world-wide information exchange on cancer therapy, a standardized treatment method for cancer is desirable. Radiation therapy for carcinoma of the uterine cervix is usually in combination with external and intracavitary irradiation. A basic treatment regiment for carcinoma of the uterine cervix with external and intracavitary irradiation was established by the major Japanese institutions. The consensus include: size and shape of irradiation field, dose, the reference from which to calculate the point A dose the external orifice of cervix is point A dose is regarded as the minor dose between right and left point As', categorized treatment methods with RALS according to cancer stage, the post operative irradiation method. This standardized treatment method will be applied for data analysis at each institution and will promote the further development of radiation therapy.

Brachytherapy↗
PubMed1982

Compensation techniques in NIRS proton beam radiotherapy.

Proton beam has the dose distribution advantage in radiation therapy, although it has little advantage in biological effects. One of the best advantages is its sharp fall off of dose after the peak. With proton beam, therefore, the dose can be given just to cover a target volume and potentially no dose is delivered thereafter in the beam direction. To utilize this advantage, bolus techniques in conjunction with CT scanning are employed in NIRS proton beam radiation therapy planning. A patient receives CT scanning first so that the target volume can be clearly marked and the radiation direction and fixation method can be determined. At the same time bolus dimensions are calculated. The bolus frames are made with dental paraffin sheets according to the dimensions. The paraffin frame is replaced with dental resin. Alginate (a dental impression material with favorable physical density and skin surface contact) is now employed for the bolus material. With fixation device and bolus on, which are constructed individually, the patient receives CT scanning again prior to a proton beam treatment in order to prove the devices are suitable. Alginate has to be poured into the frame right before each treatments. Further investigations are required to find better bolus materials and easier construction methods.

Aged↗
PubMed1979

[Theoretical derivation of a logarithmic equivalence function for the fractionation in depth therapy (author's transl)].

The effect of fractionated radiation therapy is essentially dependent on recovery of the tissues during the fractionation intervals. Supposing the recuperative capacity of irradiated tissues is lessening in the course of a depth therapy series (introduction of the term "change of the seeming recovery"), an equivalence function for fractionation is obtained and the conventional logarithmic function therefrom derived. Qualities of the here developed equivalence function are discussed.

Radiotherapy Dosage↗