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Biomedical subjects

T Kanai

Publications and source records attributed to T Kanai.

At least 271 records · Page 15Linked to original sources
PubMed1987

Radial dose distribution for 18.3 MeV/n alpha beams in tissue-equivalent gas.

Experimental measurements of the radial restricted linear energy transfer (LETr) for alpha beams of 18.3 MeV/n in tissue-equivalent gas were presented. The radial dose distribution for the alpha beam was deduced from the restricted LET measurements. A differential W value for the alpha particle in the tissue-equivalent gas was also deduced. The result for the differential W value was 29.0 +/- 0.9 eV/ion pair. The radial dose varied according to an inverse-square function with distance from the track center for radii larger than 0.026 micron. The maximum extension of the track, the penumbra radius, as 2.73 +/- 1.67 microns, which was less than predicted by calculations (7-9 microns).

Alpha Particles↗
PubMed1987

Estimation of interaction function gamma(x) with sparsely ionizing radiation.

The interaction function gamma(chi), which was introduced in the theory of dual radiation action as the probability that two energy transfers separated by distance chi combine with each other to produce a lesion, was estimated with sparsely ionizing radiation (60Co gamma rays and 40 kV X rays). Gamma(chi) was deduced on the assumption that the sensitive matrix is made up of small spherical flocculi distributed over the cell nucleus. The diameter of a flocculus was estimated at (4.0-11.2) X 10(-8) m when the diameter of the cell nucleus d was assumed to be 5 microns, and (4.0-11.4) X 10(-8) m when d was assumed to be 10 microns. It seems reasonable to hypothesize that the flocculus corresponds to the linker DNA in the chromatin structure of DNA, because the size of the linker DNA as a target (about 40 nm) is consistent with the diameter of flocculi obtained in this study.

Animals↗
PubMed1986

[A case of multiple liver metastases from sigmoid carcinoma treated successfully with arterial infusion chemotherapy].

A 63-year-old female, who had undergone sigmoidectomy for sigmoid carcinoma one year before, was admitted for multiple liver metastases. A urokinase-immobilized catheter was introduced into the proper hepatic artery via the gastroepiploic artery operatively. A daily arterial infusion of 5-FU (250 mg) was combined with a weekly arterial infusion of adriamycin (30 mg) or MMC (10 mg). After discharge, 5-FU (200 mg/day) was given orally and MMC (10 mg) was infused intraarterially every other week at an outpatient clinic. ADR or MMC was infused with angiotensin II, known to increase arterial blood supply to a malignant lesion. Ultrasonography demonstrated 35 to 50% reduction in tumor diameter. The density of metastases seen in computerized tomography became low indicating tumor necrosis. Plasma CEA level, which had initially been as high as 864 ng/ml, decreased rapidly and has remained within normal limits up to the present time. Arterial infusion chemotherapy using 5-FU, ADR or MMC in combination with angiotensin II seems to be effective in the treatment of multiple hepatic metastases from colorectal carcinoma.

Adenocarcinoma↗
PubMed1985

Proton therapy in Japan.

There are two facilities for clinical trials with protons in Japan: the National Institute of Radiological Sciences (NIRS), Chiba, and the Particle Radiation Medical Science Center (PARMS), University of Tsukuba. At the National Institute of Radiological Sciences, patient treatment with the 70 MeV proton beam began in November 1979, and 29 patients were treated through December 1984. Of 11 patients who received protons only, 9 have had local control of the tumor. Two of the 9 patients, suffering from recurrent tumor after radical photon beam irradiation, developed complications after proton treatment. In the patients treated with photons or neutrons followed by proton boost, tumors were controlled in 12 of 18 patients (66.6%), and no complications were observed in this series. Malignant melanoma could not be controlled with the proton beam. A spot-beam-scanning system for protons has been effectively used in the clinical trials to minimize the dose to the normal tissues and to concentrate the dose in the target volume. At the Particle Radiation Medical Science Center, University of Tsukuba, treatment with a vertical 250 MeV proton beam was begun in April 1983, and 22 patients were treated through February 1984. Local control of the tumor was observed in 14 of 22 patients (63.6%), whereas there was no local control in the treatment of glioblastoma multiforme. There have been no severe complications in patients treated at PARMS. The results suggest that local control of tumors will be better with proton beams than with photon beams, whereas additional modalities are required to manage radioresistant tumors.

Adult↗
PubMed1984

Corneal findings in a foetus with Fabry's disease.

The cornea of a 22-week foetus with Fabry's disease was examined biochemically and histopathologically. The alpha-galactosidase activity in the cornea was very low compared with that of the normal control. Histopathologic examination revealed that intracytoplasmic lamellar bodies surrounded by a single membrane were present in the epithelial cells. The lamellar bodies were thought to result from the abnormal accumulation of ceramide trihexoside. We conclude that ceramide trihexoside already has begun to accumulate progressively in the epithelial cells in the mid-trimester of gestation.

Adult↗
PubMed1983

Three dimensional spot beam scanning method for proton conformation radiation therapy.

In order to fully utilize the excellent dose distribution of heavy charged particles for radiation therapy a 3-D spot beam scanning method for proton conformation therapy has been developed. It is effective in reducing the dose to normal tissues compared with the ordinary beam scattering method or the 2-D spot beam scanning method. Hopefully, it will also be useful for heavy charged particle therapy in the future.

Humans↗
PubMed1983

[The range of removing fatty tissue and lymph nodes by a modified radical mastectomy with preservation of the major and minor pectoral muscles].

Thirty five patients with mammary carcinoma were selected and completeness of lymph node dissection in modified radical mastectomy (MRM) was evaluated by two step procedures, i.e., MRM was performed at the first step and then standard radical mastectomy was added immediately following the first step. Complete axillary dissection was possible in all the cases with MRM, however, in some cases, excision of the other areas was insufficient, especially in an obese patient. There were number of cases in which the number of subclavicular lymph nodes and Halsted lymph nodes felt by palpation during the MRM operation did not correspond to the actual number of excised lymph nodes. MRM may be indicated in those cases where no metastasis is observed in the histological examination of the frozen section of axillary lymph nodes during operation and/or where there is no recognizable swelling of axillary lymph nodes under palpation when the size of breast lump is less than 2 cm in diameter.

Adipose Tissue↗
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↗