J. Peter Lavender

111Indium leukocyte scanning in small-bowel Crohn's disease

Twelve patients with Crohns disease of the small bowel were evaluated by111indium leukocyte scanning of the abdomen. There was localization of the labelled cells in the areas of active Crohns disease and the findings were in complete agreement with the extent of abnormalities demonstrated on barium examination of the small intestine. The value of this technique in the assessment of Crohns disease and as an adjunct to the conventional small bowel series is discussed.

A rabbit model to study the biokinetics of radiopharmaceuticals in bone.

A technique is described using the rabbit as the ‘animal model’ to measure the rate of extraction of the bone-seeking agent, technetium labelled ethane-1-hydroxy-1, 1-diphosphonate (99Tcm-EHDP) following constant-rate infusion into the femoral nutrient artery. The extraction is shown to be approximately linear for a period of 60 min. Washout of the tracer from bone was followed for a further 60 min period and graphical analysis shows that each curve could be resolved into two distinct exponential functions. The 2-h residue of 99Tcm-EHDP in bone has been examined and is found to be dependent upon its route of administration. A high residue (43.7±5.1%) results when the infusate is delivered directly into the nutrient artery and the single muscular branch is tied off. Retrograde infusion via the femoral artery results in a lower residue (7.8±2.3%). The close correlation of these results in the rabbit with our previous findings in the dog suggests that the rabbit model described can be used to study the kinetics of other radio-pharmaceuticals during their passage through bone.