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Volume 3 (1986)
- Issue 3 Pages 135-
- Issue 2 Pages 57-
- Issue 1 Pages 1-
Volume 3, Issue 1
Displaying 1-3 of 3 articles from this issue
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Hiroshi ISOBE1986 Volume 3 Issue 1 Pages 1-22
Published: 1986
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSThe construction of a high intensity flash X-ray (FX) generator with two new types of FX tubes for biomedical radiography is described. The FX generator may be used for condenser charging voltages of 50 to 100 kV, and peak currents of 20 to 40 kA. The electric pulse width of the FX wave forms ranged from 0.2 to 0.4 μs, and the maximum intensities of the two tubes were about 70 and 150 mR at 1 m per pulse, respectively. The effective focal spots obtained by these tubes varied according to the kind of tube, the condenser charging voltage, the anode-cathode (A-C) space, etc., ranging from 0.2 to 4.0 mm in diameter. We selected two combinations of electrodes: (a) for normal focusing and a high dose rate; (b) for fine focusing and a low dose rate. The FX intensity was determined by the condenser charging voltage and the A-C distance, while the FX quality (average spectrum distribution)was determined by the average voltage of the FX tube and insertion of metal filters. Various clear FX images were obtained by controlling the FX intensity and quality. We used Fuji Computed Radiography (FCR) in conjunction with our FX radiography, and by controlling the FX quality and the focal spot size, we obtained some interesting new biomedical radiograms.View full abstractDownload PDF (11242K) -
Seihaku HIGUCHI1986 Volume 3 Issue 1 Pages 31-38
Published: 1986
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSIn this paper concerning with the parameter estimation of the blurred images, original images are assumed to be the random variables generated from the autoregressive processes, and the blurred images are considered as the degraded versions of above processes by blurred function (or onedimensional point spread function). Introducing the state variables, we will formulate this model as linear dynamical system with triplet (F, G, H). Though there are many approaches to these estimation problems, based on the correlation sequences computed from the blurred data, system parameters (F, G, H) are obtained by employing the realization method of stochastic processes. As pointed later, this approach is widely applicable to various blurred function. Simple simulation results are presented for the demonstration of the proposed method.View full abstractDownload PDF (2646K) -
Masao MATSUMOTO, Nobuyuki NAKAMORI, Hitoshi KANAMORI1986 Volume 3 Issue 1 Pages 39-50
Published: 1986
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSA high-purity germanium spectrometer system was used to measure primary X-ray spectra of 70 kVp. Methods were devised for producing and examining spectra simulating diagnostic conditions without operating the X-ray generator at high current levels. The collimations used to measure the 70 kVp spectra are discussed. The results, presented graphically, have been normalized to yield the relative number of photons per 1-keV interval. Methods for converting an exposure spectrum into a photon fluence spectrum that will produce attenuation curves of the objects (Al and acrylic resin) are presented. The results, presented graphically, have been normalized by the exposure of 3% ripple.View full abstractDownload PDF (1529K)
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