Evaluation of 99mTc-HIDA complex as a cholescintigraphic agent (author's transl)

In the reaction labeling N-(2,6-dimethylphenylcarbamoylmethyl) iminodiacetic acid (HIDA) with 99mTc, several complexes with different chemical characteristics were observed to occur with slight changes in the labeling conditions. Among these complexes, a complex detected in the bile of rats was limited to one complex, named as complex II. The preparation method of 99mTc-HIDA complex II and the exchange reaction between this complex and penicillamine indicate that 99mTc is coordinated with HIDA as low-hydrolyzed 99mTc in this complex. This complex is excreted rapidly through the bile and within 1 hr, about 65% of the total activity injected is recovered from bile in rats. The organ distribution of this complex was studied in mice by radioassay and in rabbits by scintillation camera and, in both cases, the radioactivity was accumulated in the gallbladder. These results suggest that the 99mTc chemical state, low-hydrolyzed state, relates to the bile excretion behavior of this complex, a potentially useful cholescintigraphic agent.     

Diagnostic system for assessment of left ventricular function with 99mTc-albumin (author's transl)

Diagnostic system is described that obtains a set of serial gated images (SGI) covering the entire cardiac cycles and left ventricular (LV) volume curve (VC) with high temporal resolution (10 msec). The system consists of two functional parts. The one, which is based upon an inexpensive modification of multiformat imaging device, yields SGI. The other, which is based on a minicomputer system, acquires data only from around about LV area and yields LVVC from ECG P wave without the reconstruction of these images. In as little as 5 min result, which is also corrected uniformity of gamma-camera, is given.     

Diagnostic evaluation on cerebral hemisphere scintigraphy using 99mTc-MAA (author's transl)

Using 99mTc-labeled macroaggregated albumin (99mTc-MAA), we made an examination of the cerebral blood flow distribution with various kinds of cerebrovascular diseases in 151 cases. The particle size of MAA used in this study ranged from 10 to 100 micron. Scan was performed after injection of 3 mCi of 99mTc-MAA into common carotid artery. No side effects were observed except for one case with headache. Distribution of 99mTc-MAA was found to be homogeneous in normal cerebral hemisphere but not in the lesion. Most lesion was shown as nonradioactive area. Meningioma with hypervascularity was represented as hot area. By this method cerebral infarct could be easily represented not only in main artery but also in such a very small artery as hardly detected by CAG. This method is therefore useful for detecting cerebral infarct, sequela of cerebral apoplexy, head injury and others. The dose of 99mTc-MAA used in this method is much lower compared with those of common brain scan, its excretion is speedy, and therefore internal radiation exposure is diminished.