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Biomedical subjects

R Ozawa

Publications and source records attributed to R Ozawa.

30 records · Page 2Linked to original sources
PubMed1981

A modified dose monitoring system in remote afterloading therapy of carcinoma of the uterine cervix using semi-conductor dosimeter.

A dose monitoring system in high dose rate intracavitary remote afterloading therapy of carcinoma of the uterine cervix using semi-conductor dosimeter was developed in July 1979 at our department. During early experience with the above system, extremely high values of mgh as well as high doses to rectum and bladder were encountered in the cases with poor local anatomy or unsuitable application. Solving this problem, such limitations as to the mgh as well as point-A dose were added to the computerized rapid processing system for the pretreatment dose calculation and correction of the treatment parameters to adjust the point-A dose to within +/- 5% of the planned dose. In the majority of the cases treated with Ralstron, this modified dose monitoring system brought considerable success in the optimization of point-A, mgh, rectal and bladder doses, in a simple manner.

Brachytherapy↗
PubMed1980

A dose monitoring system in high dose rate intracavitary remote afterloading therapy of carcinoma of the uterine cervix using semi-conductor dosimeter.

Our intention was to develop a high accuracy procedure in high dose rate intracavitary remote afterloading therapy of carcinoma of the uterine cervix similar to the accurate dosimetry used in external irradiation. Semi-conductor in-vivo-dosimetry was carried out in order to determine the extent of errors in the calculated dose at reference points and in the definition of point A. The use of a rapid processing computerized system before the treatment was developed in order to decrease the difference between the dose delivered at point A dose and the planned dose. Errors in calculation of within +/- 10% seemed to be unavoidable in the hgh dose rate intracavitary afterloading therapy of carcinoma of the uterine cervix. Two definitions should be used in patients to compute the point A dose according to the ovoid position. Using the rapid processing system, wo could deliver a point A dose within +/- 5% level of the planned dose. The remotely controlled afterloader was safely operated by means of in-vivo-dosimetry which was backed up in routine clinical practice by a pretreatment calculated dose.

Brachytherapy↗
PubMed1976

[Inhibition of cholinesterase activity induced by pyridaphenthion].

Inhibitory effects on cholinesterase (ChE) activity in blood of the rabbit induced by pyridaphenthion(PD), an organophosphorus compound, and effects of 2-pyridine aldoxime methiodide(PAM) on this inhibition were examined. 1) Experimental results within 24 hr: An oral administration of each dose of PD(100 approximately 750 mg/kg) gradually decreased ChE activity and ChE activity value decreased to 20.5% in the erythrocytes and 21.5% in the plasma 24 hr after administration of 500 mg/kg of PD. However, this value recovered remarkably with an intravenous injection of PAM. The ChE activity value was 55.5% in the erythrocytes and 41.4% in the plasma with a single injection, and respectively 67.8% and 59.1% when PAM was injected three times. 2) Experimental results for 14 days: Following an increase of the administered dose (100 approximately 400 mg/kg) of PD, a decrease in ChE activity was apparent and a recovery to normal values was delayed. This inhibition could be ameliorated quickly with an injection of PAM. Considering that PAM does not have remarkable detoxicative effects on organophosphorus compounds which have a low toxicity, PAM appears to be a promising antidote against PD.

Administration, Oral↗