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Biomedical subjects

T A Iinuma

Publications and source records attributed to T A Iinuma.

At least 19 recordsLinked to original sources
PubMed1992

[Evaluation of performance in diagnosis of pneumoconiosis using FCR (Fuji Computed Radiography)].

The purpose of this study was to determine the applicability of the FCR system to the diagnosis of pneumoconiosis. In the study, images of pneumoconiosis obtained by FCR were collected from the Rosai Hospital for Silicosis, and the distribution, shape and size of small opacities of pneumoconiosis were determined by three of the authors. An image data base was prepared, and diagnosis of pneumoconiosis using FCR test films was performed by 12 physicians with reference to reduced ILO films. Among the data obtained, data relating to profusion were analyzed. The results were compared with those obtained in the previous study. It was found that, if suitable image processing was carried on FCR test films, profusion could be classified with an accuracy equal to that of the diagnosis of pneumoconiosis with usual full-size films. It was necessary to establish standard films obtained by FCR in order to improve the accuracy of diagnosis of pneumoconiosis using FCR.

Evaluation Studies as Topic↗
PubMed1991

Quantitative measurement of uptake of radiolabeled monoclonal antibody by means of planar data.

Data obtained from planar images were used to measure the uptake of monoclonal antibody in organs and tumors. Background counts included in the region of interest were eliminated, and the attenuation of the photons emitted by the radionuclide through the intervening tissues was compensated for. The background counts and the intensity of the attenuation were determined from the results of phantom studies and numerical integration with a personal computer. The quantitative uptake of 111In labeled anti-melanoma Monoclonal Antibody (ZME-018) in a melanoma lesion, the liver, and the bone marrow of a patient was measured by the planar method which we developed.

Antibodies, Monoclonal↗
PubMed1991

[The group study of diagnostic efficacy of cerebro-vascular disease by I-123 IMP SPECT images obtained with ring type SPECT scanner--the ROC analysis on the diagnosis of perfusion defect and redistribution].

We performed two image reading experiments in order to investigate the diagnostic capability of I-123 IMP SPECT obtained by the ring type SPECT scanner in cerebro-vascular disease. Fourteen physicians diagnosed SPECT images of 55 cases with reference to clinical neurological informations, first without brain XCT images and second with XCT images. Each physician detected perfusion defects and redistributions of I-123 IMP and assigned a confidence level of abnormality for these SPECT findings by means of five rating method. From results obtained by ROC analysis, we concluded as follows: (1) Generally, I-123 IMP SPECT is a stable diagnostic modality in the diagnosis of cerebro-vascular disease and the image reading of XCT had no effects on the diagnosis of SPECT on the whole of physician, (2) However, there were unnegligible differences among individuals in the detectability of findings and the effect of XCT image reading, (3) Detectability of redistribution of I-123 IMP was lower than that of perfusion defect and inter-observer variation in the diagnostic performance for redistribution was larger than that of perfusion defect. The results suggest that it is necessary to standardize diagnostic criteria among physicians for redistribution of I-123 IMP.

Amphetamines↗
PubMed1990

[Determination of the point position from two orthogonal X-ray photographs using least squares method and geometrical solutions].

Six sets of solutions for calculating the position of an interest point were obtained geometrically using four measured image coordinates on two X-ray photographs orthogonally projected. When the image coordinates had no error, all the solutions gave the same position without error. When an error occurred, the calculated positions differed from each other due to the propagation of error. Some solutions could not be used for this determination owing to a large propagation of error. Under conditions similar to those of clinical practice, the ratio of maximum error of position calculated by the six geometrical solutions to minimum error was about 426. The least squares method that we proposed gave results with less error. When one of the image coordinates could not be measured for some reason, the least squares method became automatically equivalent to one of the six geometrical solutions.

Image Processing, Computer-Assisted↗
PubMed1990

Carbon-13 NMR imaging study of in-vivo glucose metabolism.

Carbon-13 NMR spectroscopy and chemical shift selective imaging studies of in vivo glucose metabolism were performed at 2.0 T. Some metabolite peaks were observed in 13C NMR spectra, and carbon NMR imaging focused in the spectral region attributed to D-1-13C-glucose were also performed. A 13C NMR signal accumulated in the liver was detected and the average time resolution of these spectra and images were 10 and 30 minutes, respectively.

Animals↗
PubMed1989

[Risk-benefit analysis for mass screening of breast cancer utilizing mammography as a screening test].

Incidence of breast cancers in Japanese women is increasing steadily. Mass screening of breast cancer was started in Japan under auspices of Adult Health Promotion Act of the Japanese Government from 1987. As the first screening method, the palpation of breasts is employed at present, but it is expected to be replaced by the mammography. In this report, the risk-benefit analysis is presented between risk of breast carcinogenesis due to radiation and benefit of mass screening of breast cancer. The benefit of mass screening is taken as the net elongation of average life expectancy of women due to survival from breast cancers. The risk of mammography is taken as the net loss of average life expectancy of women due to breast carcinogenesis. In the latter, the latency time and plateau period of radiation carcinogenesis were taken into consideration in the calculation. The results show that the ages at which the benefit and risk become equal are between 30 and 35 years old when dose equivalent of mammography is between 10 and 20 mSv, that are conventionally used. However, the critical age will be reduced to 20 years old if the dose equivalent becomes 1 mSv. Therefore, it is strongly recommended that a low dose mammographic system should be developed in order to achieve 1 mSv for the mass screening of breast cancer of Japanese women. In author's opinion, this is quite feasible by employing a new digital radiography with imaging plate.

Adolescent↗
PubMed1989

[On the assessment of the diagnostic accuracy of imaging diagnosis by ROC and BVC analyses--in reference to X-ray CT and ultrasound examination of liver disease].

To achieve an effective assessment of diagnostic accuracies of currently used imaging methods on liver diseases, X-ray CT (CT) and realtime ultrasound (US), ROC analysis and a new analysis method, "the bias to variance characteristics (BVC)" were applied in parallel. The survey has been carried out to assess an image interpretation accuracy on cases with established diagnosis collected on the multi-institutional basis. The images, CT and US of liver diseases including localized and diffuse lesions were selected for image reading sessions and the interpretative difficulties were geared to an appropriate grade so that it does fit to the basic requirement of ROC analysis. Consequently, 91 cases were selected from a total of 258 cases which were collected from 16 institutions. Two image reading sessions were scheduled and a total of 28 radiologists and sonologists undertook the first session. The final analysis covered 8 radiologists for CT and 9 sonologists who carried out both sessions. The image interpretation results were fed to the computer and analyses were made accordingly. Analysis of the first image reading session gave true positive ratios (TPR) of CT and US as 92.5% and 97.4%, and true negative ratios (TNR) of 50.5% and 46.8%, respectively. The second reading session, in which both CT and US images were interpreted simultaneously, gave the similar values of TPRs, 96-97% and TNRs, 44-47%. The ROC analysis of existence of liver mass and diagnosis of malignancy resulted in the higher values in US compared to CT in the first separate reading, however, the 2nd session gave almost identical values in each modality. The diagnostic accuracy for the benign tumors, mostly consisted of hemangioma, CT reading gave higher accuracy rates compared to the US. The entirely new interpretations scheme, arbitrarily named as BVC was carried ou on matrix data obtained in the same experiment. The scatterograms plotted according to the BV values, the mean and the standard deviation inherent to individual cases have demonstrated marked variations among individual cases most likely reflecting the interpretative difficulty of respective images, thus indicating the method to be well in adjunct to the ROC analysis.

Adult↗
PubMed1989

Computer system and software of POSITOLOGICA II: a whole body positron emission tomograph.

Since a whole body PET-scanner POSITOLOGICA II was installed at the National Institute of Radiological Sciences (NIRS) in 1982, improvements of the computer system and developments of new software have been continuously made to correspond to clinical requirements. As the result, POSITOLOGICA II possesses one of the most powerful systems and sophisticated software in Japan. This report describes the present status of the computer system and software of POSITOLOGICA II. It also discusses problems which still exist and proposes a future computer system for the PET study.

Brain↗
PubMed1989

[Cancer diagnosis by medical images with reference to medical physics].

Medical imaging technology has developed dramatically during recent 15 years, triggered by X-ray computed tomography. Cancer diagnosis has been greatly influenced by newly invented devices such as XCT, ultrasound, and MRI. In this report, a brief historical review is made of medical imaging after 1973 when XCT appeared on the market. Cancer diagnosis is divided into various stages such as detection, diagnosis, staging, planning, verification, response to therapy, follow-up, relapse and restaging. The effect of each imaging modality on various stages of cancer diagnosis is explained, and future directions are suggested. Finally, the picture archiving and communication system (PACS) is illustrated in detail in relation to cancer diagnosis. PACS will not only improve the diagnostic efficacy of cancer, but also contribute to reduction in health care expenditures. Thus, it is one of the most important goals of medical physicists for medical practice in the 21st century.

Diagnostic Imaging↗
PubMed1988

A method for calculating the optimum irradiation condition for intracavitary radiotherapy using quadratic programming.

A method of calculating optimum irradiation conditions for intracavitary radiotherapy using quadratic programming has been formulated and then modified for practical application. The allowable range of obtained dose, which is usually fixed in advance, is automatically computed to be as small as possible. The variance of the product of the activity and the irradiation time of the tandem source is also minimised to avoid the occurrence of cold and/or hot spots. Optimum irradiation conditions for conventional intracavitary radiotherapy of carcinoma of the uterine cervix were obtained on the basis of isodose curves passed through the points A of the Manchester system. Those for carcinoma of the other organs and special cases of carcinoma of the uterine cervix can be determined after consideration of the tumour state.

Brachytherapy↗
PubMed1987

Noninvasive quantification of regional myocardial blood flow and ammonia extraction fraction using nitrogen-13 ammonia and positron emission tomography.

This report describes the theoretical basis and a method to quantitate regional myocardial blood flow (RMBF) and ammonia extraction fraction (E) in man, noninvasively, with N-13 ammonia and positron emission tomography (PET). Two patients with hypertrophic cardiomyopathy, whose left ventricular (LV) walls were markedly thick, were employed in this study to avoid partial volume effects and cross contamination between LV walls and blood pool. RMBF and E were calculated from time-activity curves of myocardial tissue and left atrium derived from serial 6-second PET images of the heart. The time-activity curve of left atrium was used as an arterial input function. The results were RMBF = 67 +/- 4 ml/min/100 g, E = 80 +/- 13% and 65 +/- 10 ml/min/100 g, 81 +/- 16% for each patient. The validity of the present method was discussed.

Ammonia↗
PubMed1987

[Count rate characteristics and count loss correction of Positologica II: a whole body positron emission tomograph].

This paper describes evaluation and correction of count rate characteristics of POSITOLOGICA II, a multi-slice whole body positron emission tomography system. The present study was performed using three phantoms; a 5 cm inner diameter, water-filled lucite cylinder, a 20 cm inner diameter, water-filled lucite cylinder and a chest phantom. After injection of high activity (about 1.85 GBq (50 mCi] of 13N ammonia into each phantom, rates of true coincidence, random coincidence and single photon detections were measured during decay of the isotope through more than two orders of magnitude of activity. At very high levels of activity, count rate characteristics of the system were saturated and limited to 660 kcps of total coincidence rate, which was the sum of rates in on-time and off-time windows, by the FIFO (first-in first-out) output frequency. Below those levels of activity the relationship between count loss and true coincidence rate was not unique but depended on the phantom configurations, suggesting that count loss correction using the above relationship was inadequate for quantitative study. However, the relationship between count loss and single rate was almost independent of the phantom configurations. Thus in conclusion count loss could be corrected using single rate for POSITOLOGICA II. A practical method of count loss correction was also proposed.

Models, Structural↗
PubMed1987

Automatic radiologic reporting system using speech recognition.

A radiograph report is usually made from an oral dictation by a radiologist, which is then typed. Typing Japanese is rather inconvenient and consumes many hours. In this paper we introduce a computer-assisted reporting system for radiologic images using speech recognition. The hardware of the reporting system consists of a speech recognizer DP-200(NEC) and a personal computer PC-8801 or PC-9801. The DP-200 has the capability of storing 500 different words spoken by a radiologist. At present, three application programs have been designed. These are for the interpretation of a liver scintigram, a bone scintigram and a chest radiograph. Data entry is done by the radiologist at a CRT display terminal in a conversational manner with predefined and predetermined branching. The time required to make a normal report using the liver or bone scintigram system was within one minute. The reporting time was several minutes in the case of an abnormality report. It is suggested that the system is useful for making an imaging report, for constructing the data base for the interpretation of medical images and for the picture archiving and communication system.

Bone and Bones↗