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[en] Osteoporosis is often diagnosed after fracture occurrence, when therapy is less effective. The dual photon densitometry has been the proposed method for osteoporosis early diagnosis. In the present study is presented our experience on the lumbar vertebral and femoral neck bone mass measurement by utilizing a Lunar DP-3 densitometer in normal young 82 volunteers and 103 women with radiologically and clinically diagnosed osteoporosis. The values found in osteoporotical patients were significantly lower when compared to those normals either in lumbar vertebrae (L2-L4) or in the femoral neck. The method's coefficient of variation was <0.5%, when determinated with a synthetic phanton aid and <1.5% repeating the exam in 10 normal volunteers. These results show that dual photon densitometry is a simple, sensitive and non-invasible method for early diagnosis and therapeutic follow-up of osteoporotical patients. (author)
[pt]A osteoporose e frequentemente diagnosticada somente apos o aparecimento de fraturas, quando a terapia e menos efetiva. A densitometria por dois fotons tem sido o metodo proposto para o diagnostico precoce dessa doenca. No presente estudo, relatamos nossa experiencia na medida de massa ossea das vertebras lombares e femur proximal utilizando um densitometro DP-3 Lunar em 82 voluntarias jovens normais e 103 mulheres com osteoporose diagnosticada clinica e radiologicamente. Os valores encontrados nas pacientes com osteoporose foram significativamente inferiores aos normais, tanto em coluna lombar (L2-L4) como em femur proximal. O coeficiente de variacao do metodo foi <0,5%, quando determinado com auxilio de um phantom sintetico, e <1,5%, repetindo-se o exame em dez voluntarias normais. Esses resultados confirmam que a densitometria por dois fotons e um metodo simples, nao invasivo e sensivel para diagnostico precoce e acompanhamento terapeutico de pacientes portadores de osteoporose. (autor)
[en] This study was undertaken to investigate the relationships film and processing solution at different processing temperature. Three kinds of periapical film were used for this study. They included EP-21 film, DF-58, and A film EAch film was processed by automatic film processor with RD-III, X-dol 90, and A processing solutions at 68 degree, 74 degree, 80 degree, 86 degree, and 92 degree F. Film density was measured with the densitometer, and base plus fog density, film relative speed, film contrast, and subject contrast were evaluated. The following results were obtained: 1. As the processing temperature was increased, base plus density was increased. Inadequate base plus fog densities were obtained with three films in combination with three processing solutions at 92 degree F. 2. Lowest base plus fog densities were obtained with A film, followed in ascending order by EP-21, and DF-58 film i n combination with A or RD-III processing solutions. The sequence of base plus fog densities was in ascending order by EP-21, A, and DF-58 film in combination with X-dol 90 processing solution. 3. The sequence of film relative speed values was in ascending order of EP-21, A, and DF-58 film in combination with A and RD-III processing solutions, respectively.
[en] Quantitative angiography of coronary arteries using densitometry is less sensitive than edge detection to variations in imaging system resolution, quantum noise, and stenosis cross-sectional shape. In theory, densitometry more directly measures stenosis cross-sectional area which is more closely related than vessel diameter to coronary flow of hemodynamics. However, densitometry is much more sensitive than edge detection to densitometric non-linearities, oblique projection of the artery, and overlap with other structures. The potential error from each of these sources is large, perhaps as much as 50 percent. Overlap and obliquity problems can often be identified by inspection of the angiogram and can be reduced by careful selection of radiographic views, although in many cases lesions are located such that it is impossible to obtain views which avoid both overlap and obliquity. Important progress has been made recently on the correction of densitometric error due to scatter and veiling glare. The most promising approaches use a blurred and scaled version of each image to produce an estimate of scatter and veiling glare which is then subtracted from the raw images. Initial results with this type of algorithm appear able to reduce the densito-metric error in coronary cross-sectional areas to less than 10 percent. Thus, at the present time it seems possible to perform quantitative densitometric angiography with a total error between 5 and 20 percent. Densitometric error depends on factors which differ from those influencing edge detection, and therefore the information from stenosis densitometry may be used to complement that from the edge detection. (author). 15 refs.; 7 figs.; 1 tab
[en] The fourth study meeting 'Tree growth rings' was held in Tomakomai Experimental Plantation attached to the Department of Agriculture, Hokkaido University, different from what it used to be. Though the attendance and the papers presented were not many because of the distance and the improper timing, it was very delightful that the meeting became an earnest gathering. In this report, seven papers presented at the meeting are collected. (K.I.)
[en] A report on the LOFT advanced densitometer lab testing that was conducted at ARA-3 in preparation for the non-nuclear L1-4 blowdown at LOFT is presented. The densitometer uses a pulse height analysis method for determining PWR coolant fluid chordal average density. The average density of the coolant fluid along the Cs-137 gamma beam path is determined by measuring the uncollided flux count rate in a Cs-137 photopeak and knowing the LOFT primary coolant hot leg piping geometry. This is an application of a gamma densitometer technique which processes discrete pulses and with no pulse pile-up or integration taking place. Time sampling of the piping and fluid attenuated Cs-137 spectrum provides the data which is related to the changing coolant fluid density as a function of time
[en] The purpose of this study was to propose the utility which was evaluated the digital image processing and clinical application of the video densitometry. The experiments were performed with IBM-PC/16 bit-AT compatible, video camera (CCdtr55, Sony Co., Japan), an colormonitor (MultiSync 3D, NEC, Japan) providing the resolution of 512 X 480 and 64 levels of gray. Sylvia Image Capture Board for the ADC (analog to digital converter) was used, composed of digitized image from digital signal and the radiographic density was measured by 256 level of grey. The periapical radiograph (Ektaspeed EP-21, Kodak Co., U. S. A.) which was radiographed dried human mandible by exposure condition of 70 kVp and 48 impulses, was used for primary X-ray detector. And them evaluated for digitized image by low and high pass filtering, between aluminum equivalent values and the thickness of aluminum step wedge, aluminum equivalent values of sound enamel, dentin, and alveolar bone, the range of diffuse density for gray level ranging from 0 to 255. The obtained results were as follows: 1. The edge between aluminum steps of digitized image were somewhat blurred by low pass filtering, but edge enhancement could be resulted by high pass filtering. Especially, edge enhancement between digital root of lower left 2nd molar and alveolar lamina dura was observed. 2. The correlation between aluminum equivalent values and the thickness of aluminum step wedge was intimated, yielding the coefficient of correlation r=0.9997 (p<0.001), the regression line was described by y=0.9699X + 0.456, and coefficient of variation amounting to 1.5%. 3. The aluminum equivalent values of sound enamel, dentin, and alveolar bone were 15.41 mm, 12.48 mm, 10.35 mm, respectively. 4. The range of diffuse density for gray level ranging from 0 to 255 was enough than that of photodensitometer to be within the range of 1-4.9.