| Research Abstract |
It's reported that the duodenum and the small intestine of the activity excreted from the liver and gallbladder can lead to interference with the myocardial uptake. To study how precisely images reflect tracer uptake in a myocardium, as fundamental experiment to examine the influence that accumulation of the liver and alimentary tract (except esophagus) of the activity excreted from the liver gave to the myocardium image in the technetium-99m myocardium perfusion tracer, we administered ィイD199mィエD1Tc-tetrofosmin (following, Tetrofosmin) to a normal rat and compared with measured value obtained by a gamma camera and an actual survey value after the organs extraction. Methods : Thirty-three rats were measured for 5, 10, 15, 30, 45, 60, 90 and 120min after the administration of Tetrofosmin. The accumulated rates for the myocardium, the lung, the liver, the duodenum, the small intestine, the rectum and the blood with a well-type scintillation counter (WC) were assessed as a percentage of t
… More
he injected dose per gram of tissue (%ID/g). The accumulated rates for each organ with the planar imaging (PI) were assessed as a percentage of the injected dose per pixel (%ID/pixel) establishing regions of interest (ROIs) in each organ. The accumulated rates for each organ, the PI-to-WC ratio and the heart-to-organ ratios calculated by PI and WC were compared. Results : The accumulated rate for the heart with WC increased until 30 min (1.671%±0.306%) after the injection, and subsequently decreased. On the other hand, peak of the accumulated rate with PI was shown at 15 min (1.814%±0.518%) after the injection. Particularly a difference of both was higher in 10 min (PI/WC ratio : about 1.6 times) of the early phase. The accumulated rate for the lung with WC was maximum at 15 min (0.870%±0.312%) after the injection. The accumulated rate with PI, however, showed the maximum value at 10 min (1.139%±0.376%), and a variation of the accumulated rate was hardly recognized 10 min later. The accumulated rate for the liver with WC was hardly shown a marked variance from 5min (0.768%±0.193%) to 30min (0.692%±0.273%), and a tendency of decrease was showed slowly. On the other hand, the accumulated rate with PI was more highly than that with WC in the whole, and high values were showed in 10 min (PI/WC ratio : about 3.3 times) and 15 min (PI/WC ratio : about 2.3 times) in particular. The accumulated rate for the duodenum and the upper small intestine was maximum in 10 min (1.228%±0.602%, 2.245%±1.936%) after the injection, and approximately 90% of ィイD199mィエD1Tc-tetrofosmin were the duodenum excrements. Conclusion : The accumulated rates for each organ with PI were showed higher than that with WC. The difference of both, particularly, was stronger in early phase after the injection. The accumulated rate for the heart with PI was shown significant higher than that with WC at 10 min. The interference of Compton scatter from the liver, duodenum and small intestine was suggested as one of these causes. Less
|
