Abstract
170Tm-citrate has recently been reported to concentrate in nonosseous tumor tissue in animal study. We produced 167Tm by 168Yb (r, n) 167YbEC→167Tm reaction which had suitable property for tumor scanning. To investigate whether 167Tm produced by this method has strong tumor affinity, 168Tm-citrate was intravenously injected to the rats subcutaneously transplanted Yoshida sarcoma. And the distribution of168Tm in the body was determined at 3, 24 and 48 hours after administration.167Tm-citrate (carrier free) and167Tm-citrate (containing Tm of 5μg) had the same strong tumor affinity as170Tm-citrate in the previous experiment, but167Tm-citrate (containing Tm of 50μg) did not have the tumor affinity.167Tm-citrate (carrier free) and167Tm-citrate (containing Tm of 5μg) had the considerably strong bone affinity, but it was not concluded that167Tm-citrate was a more excellent bone scanning agent than 99mTc-labeled phosphonate.167Tm-citrate (carrier free) had the considerably strong affinity for inflammatory tissue as169Yb-citrate had. From above described results, it was clearly shown that167Tm-citrate produced in our new method had strong tumor affinity.
