This report deals with a method about clinical application (Ca-47 absorption test) of a scintillation camera in place of a whole body counter. The performance characteristics examined are as follows. 1. The useful field of the modified collimator was a rectangle (Set up field) in its shape, facing the moving subject. The counter was suited for detecting γ-ray energies from 400 to 680 keV. The effective detector-to-body distance was 56 cm. The speed of bed movement for signal-accumulation was 130 cm/min. 2. The background count was relativly high. The coefficient of its variation during 15 days was 0.6%. 3. The applied scintillation camera operated most usefully in the detection range from 0.2μCi to 40μCi. 4. Values of Ca-47 absorption rate in the various diseases measured by a regular and the present method was fairly close with a coefficient of correlation of 0.984. 5. The proposed method for the application of scintillation camera for the purpose of whole body counting was favorable in view of its simplicity and reliability for the routine Ca-47 absorption test without quantitative treatment of feces.
Recently, short exposure time radiograph has been possible to carry out due to the application of high sensitivity image recepting system and heavy duty X-ray tubes to reduce patient irradiations. Generally, on the clinical radiographic experience, there are questions about performance stability of X-ray generators during such short exposure durations as 0.1s or less than that. To investigate the short time exposure characteristics of X-ray generators, we took X-ray strobographs by means of an X-ray stroboscope which was circulated around the members of the study group. Fourty five X-ray generators in 15 hospitals were measured. Results show that there are many incorrect performances such as pull-in, pull-out phase failures, tube voltage waveform distortions, transient-like X-ray intensity change, and numbers of exposure pulse failures. Reproducibility failures due to these abnormalities also can be observed. Further, more precise measurements are carried out with an X-ray tube voltage current meter a fluorescence meter, and an oscilloscope. We call the performance measurement the X-ray generator dynamic study. The measurement results also show that the X-ray generator's dynamic characteristics at such a short exposure time are insufficient. As described above, short exposure time radiography is not easy technique, at present. By further technological investigations, we can utilize this usefull technique.
Concerning the integrated body imaging, an optimization of technical aspect in each modarities, such as radiation burdun, labour turnover and cost effectiveness shoud also be considered, in diagnostic process. After investigation on these items, we decided to recomend that imagings of Ultrasound, radionuclide and plain X-ray film shoud be the first choice for screening, then, CT and X-ray contrast study be the second selected choice and lastly, elabolated contrast angiography be the last one to be selected, if it is necessary. As the increase of information dimension in appeared to be accompanied by the increasing burden in various technical aspect, technical effort to extract more information than those at present at the same burden should be worthwise in future.
Comparative study of analysis of left ventricular wall motion and estimation of ejection fraction at cine- and radionuclide angiography was carried out. Ejection fractions of the left ventricles, estimated by cine- and radionuclide angiographical method showed good correlation of r=0.81. At segmental anlysis of the left ventricular wall motion, we could not find any differences between the wall motion of both left ventriculographies, except movements of the apical segments. Apical segments of the left ventricles showed a tendency to overact at radionuclide left ventriculography more than cine left ventriculography.
The correlation between multi-gate radionuclide cardioangiography with ^<99m>Tc-HSA and left ventricular angiography about left ventricular ejection fraction is excellent (γ=0.902) in the diagnosis of ischemic heart disease. Moreover, right ventricular ejection fraction is high precision, and its value is more dependable than cardiac catheterization by correcting the motion of tricaspid valve. The rate of coincidence between multi-gate radionuclide cardioangiography and left ventricular angiography is totally 84 percent about 7 segments of A・H・A (American Heart Association) standard on the fifty examples at the estimation of wall motion, however, it sign low value because of doubling left ventricular and right ventricular with segment 1,2,5. But it can be improved by collecting the list mode at first-pass radionuclide cardioangiography, and this way of collecting date is valuable for right ventricular infarction. The slant-collimator is valuable for the diagnosis of ischemic area by myocardio scintigraphy with ^<201>Tl.
Recently, owing to developments of high out put X-ray tube, high resolution image intensifier and mobile U or C arm, increasing remarkably, has been application of cinegraphy to angiocardiographic study. Surgical treatments for heart diseases have been very advanced in this few years, so that before operation, is demanded to precise anatomically and functionally diagnosis of them. In this paper, are discussed cineangiocardiography, echocardiography, in regard to the most useful investigation of valvelar heart diseases and some problems of imaging techniques, finally, introduced the newest examination method of diagnostic imaging.
The diagnostic importance of abdominal ultrasonography has already been well established. In our institution we have carried out abdominal ultrasound and clinically obtained excellent results. In this paper we made ultrasound should diagnosis of hepatomas and studied their visual characteristics. We concluded ultrasound should be a main diagnostic armamentarium to visually diagnose hepatomas. Ultrasound is the most effective screening method of liver tumors and its non-invasiveness is most suitable for the early detection of hepatomas. It is also a very useful method to follow patients suspected of having metastatic liver tumors. We employed both contact scanner and mechanical sector. Contact scan is very appropriate to obtain a whole picture of the liver. Mechanical sector accurately visualizes lesions below right hepatic lobe.
What the detectability of renal mass lesions was studied retrospectively is comparison between renal scintigraphy with ^<99m>Tc-DMSA and intravenous urography. Two different techniques were used in intravenous urography : one was the single or standard dose (60% water-soluble contrast medium 40ml), the other was the double or high dose (contrast medium 80ml). Films were made after injection of contrast medium at 3 min, 10 min, and 20 min, in the single dose technique, and at 0 min (nephrogram), 3 min and 12 min in the double dose technique. In summary, it is much easier to detect the renal mass lesions by renal scintigraphy with ^<99m>Tc-DMSA as compared with the single of standard dose technique, while the double or high dose technique can demonstrate readily the renal mass lesions as renal scintigraphy with ^<99m>Tc-DMSA does. The reason why the single dose intravenous urography is not effective to detect the renal mass lesions will be that the renal density (nephrogram) is not uncommon to be insufficient.
For the purpose of improving diagnostic efficacy integrated evaluation of various medical images is very important. We attempted to display the digital images of different modalities, such as nuclear image and X-ray CT image, simultaneously and the usefulness of this method is reported. LFOV gamma camera and scintillation scanner (Elscint ) were used for nuclear imaging and CT/T 8800 (G.E.) was used for XCT imaging. Nuclear images stored by Scintipac 200 (Shimadzu) were transfered using magnetic tape to the mini-computer attached to CT system. Our computer programs include (1) composite display of scintigram and XCT image, (2) reconstruction and display of RCT image associated with coronal and sagittal images, (3) superimpcsing display of RCT image and XCT contour image and (4) cine mode display of multi-view original images for RCT reconstruction. Composite display of nuclear image and XCT image made it easier to evaluate each image complementarily, as regional function image and morphological image respectively. Superimposing display of RCT image and XCT contour image was useful for identification of functioning tissues in relation to the adjacent organ structures. Cine mode display of ratating original images for RCT was helpful for three dimentional observation of nuclear image.