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Biomedical subjects

M Koakutsu

Publications and source records attributed to M Koakutsu.

At least 19 recordsLinked to original sources
PubMed1991

[Diagnosis of pancreatic cancer using 201Tl-chloride and a three-head rotating gamma camera SPECT system].

201Tl SPECT was performed on 17 patients with pancreatic cancer or chronic pancreatitis using a three-head rotating gamma camera SPECT system. In 7 of 10 patients with pancreatic cancer, the lesions were clearly delineated by 201Tl SPECT. Whereas the lesion of 30 mm in diameter was visualized, a large tumor of 80 mm in diameter could not be visualized. Namely, it was thought that 201Tl uptake by pancreatic cancer might be well correlated with tumor blood flow and/or its histological subtype rather than with tumor size. In 5 of 7 patients with chronic pancreatitis, no uptake by the pancreas was shown. The sensitivity, specificity, and accuracy in diagnosing pancreatic cancer by 201Tl SPECT were 70%, 71%, and 71%, respectively. The present results obtained by 201Tl SPECT were thought satisfactory enough to evaluate pancreatic cancer under the present conditions where there was no useful imaging agent for visualizing pancreatic cancer by SPECT. 201Tl SPECT is expected to be a new diagnostic tool for investigation of pancreatic tumorous lesion.

Adenocarcinoma↗
PubMed1991

[Blood flow measurement of brain tumor by 123I-IMP using 3-heads rotating gamma camera SPECT].

Using 3-heads rotating gamma camera SPECT system, regional blood flow was measured from the super-early image obtained 4 to 6 minutes after the intravenous injection of 123I-IMP on 11 patients with various brain tumors. Two cases of olfactory groove meningioma and malignant astrocytoma showed significantly high 123I-IMP uptake by the lesion visualized by MRI compared to the uptake by normal brain cortex on super-early image but 123I-IMP uptake by the tumor decreased on early image. In both cases, blood flow of the tumor measured from super-early image showed values much higher than those of normal brain cortex. It was thought that usual correction method based on early image did not correctly represent the blood flow of the lesion but that the present method based on super-early image could show the increase of blood flow of the tumor.

Adult↗
PubMed1990

[Factor analysis in thallium-201 chloride thyroid studies].

Factor analysis was applied to thyroid thallium-201 imaging to get separated image of tumor from normal thyroid tissue. Thirty-eight patients with various thyroid tumors which were histologically confirmed were included in this study. Following intravenous injection of 111 MBq (3 mCi) of 201Tl chloride, thyroid images in 64 frames were taken for 30 to 60 minutes using Toshiba gamma camera system and data were analyzed by 2 or 3 factor analysis. In 28 of 38 patients separated images of the lesions from normal thyroid were obtained and time-activity curves of various shapes corresponding to the lesions were also obtained. When the curves were classified into 3 groups according to their shapes: increasing, flat and decreasing, follicular carcinoma did not show increasing shape whilst neither of papillary carcinoma, squamous cell carcinoma and anaplastic carcinoma showed decreasing shape. The shapes of the curves were thought to be reflected in clearance of the agent from the lesions. Factor analysis in 201Tl chloride thyroid scan provided separated image of tumor from normal thyroid gland automatically and the obtained curves corresponding to the lesions provided information for estimating the characteristics of thyroid tumors.

Adult↗
PubMed1989

Two cases of adenocarcinoma of the lung in which thallium-201 gave a better delineation of metastatic lesions than gallium-67.

The authors report two cases of adenocarcinoma of the lung in which Tl-201 gave a better delineation of metastatic lesions than did Ga-67. In the case of multiple bone metastases, the metastatic lesion of the skull was clearly demonstrated by Tl-201 but not by Ga-67. In another case of multiple brain metastases, the lesions were also visualized by Tl-201 but not by Ga-67. Tl-201 is occasionally superior to Ga-67 for visualizing metastatic adenocarcinoma of the lung.

Adenocarcinoma↗
PubMed1983

[Quantitative study of single photon radionuclide computed tomography--delineation of body contours].

Several methods to obtain the body contour which is necessary to reconstruct the quantitative images with single photon radionuclide computed tomography (SPRCT) are described in this paper. A multipurpose gamma camera system which is composed of 2 detectors, data processor and others were used to collect the data of SPRCT and body contour. An iterative reconstruction technique was implemented to reconstruct the image. Three methods for obtaining the body contour were tested. The first method utilizes X-ray CT data. The data which are obtained by GE CT/T are transferred to the data processor of SPRCT through the off-line magnetic tape and delineate the body contour. The second method uses a transmission source which was attached on the opposite side to detector. The third method uses gamma-rays which are generated by Compton scatter in the tissue of patient. The first and the second methods were able to use to obtain the body contour, but the contour obtained by third method was not accurate.

Gamma Rays↗
PubMed1982

[Clinical evaluation of transaxial bone imaging with 99mTc-phosphate compounds].

Single photon emission computed tomography using newly designed whole body imaging system which was composed of opposing dual gamma cameras, a rotating gantry and a sliding table was clinically evaluated for bone imaging. Two hundred and seventeen portions of various bone diseases were performed single photon emission computed tomography following conventional bone imaging with 99mTc-MDP (methylen diphosphonate) or -HMDP (hydroxymethylene diphosphonate) and the results were discussed. Transaxial images were sometimes superior than conventional images in the diagnosis of the tumor localization and extension of the facial bone. Combination of emission computed tomography to conventional methods also presented more exact informations for the diagnosis of the vertebral change. Separation of the overlapped radioactivities of the bone and the soft tissue is another advantage of the tomographic image, and cross-sectional images with enoughly high qualities were available in early time after administration of 99mTc-phosphate compounds. Useful diagnostic informations could be obtained by tomographic bone imaging combined with conventional imagings.

Adult↗
PubMed1982

[RCT image study by angular interval of sampling].

A multi-purpose gamma camera system which had 2 detectors of opposed position and was capable of radionuclide computed tomography (RCT) imaging was installed in Division of Nuclear Medicine, Chiba Cancer Center Hospital. In this study, the variance of RCT image due to the angular interval of sampling was analyzed. The full width at half maximum (FWHM) and full width at tenth maximum (FWTM) of point source were almost same for all sampling intervals investigated. The distortion of RCT images with uniform activity source could not be detected even for larger intervals. When the RCT images were obtained using a phantom contained 3 line sources and a bar phantom for RCT which were located at right angle with the plane of reconstruction, the images did not change between 1 degrees and 6 degrees of sampling interval, but for 9 degrees or more the distortion of images occurred explicity. For our system, sampling interval of 2 degrees was predicted from the theorectical calculation considering both resolution and statistical noise. But, results from the phantom studies of present work showed that sampling interval of 6 degrees was sufficient to reconstruct RCT images without distortion, and could be applicable to dynamic RCT images.

Models, Structural↗
PubMed1979

[Single photon radioisotope emission computed tomography image using gamma camera (author's transl)].

Single photon radioisotope computed tomography (RCT) images were obtained using the following devices such as conventional gamma camera, data processer for exclusive use of nuclear medicine (C.D.S.-4096), magnetic tape and medium size electronic computer FACOM 230-28S (48K) for multipurposes, which are routinely used for clinical purpose. To reconstruct the RCT image we made absorption correction by geometric mean of opposing counts considering the thickness of source and used the convolution integral method. The reconstructed images of phantom study resolved one centimeter clearly and were very similar to original. The RCT image of patient was acquired by the rotation of patients using the revolving chair and the handmade implement which settles the center of patient's head. Three dimensional informations were obtained by one examination with a gamma camera which collects two dimensional images. When using a gamma camera, therefore, not only a transaxial but an arbitraly RCT image will be important to contribute for diagnosis.

Brain Neoplasms↗