Radioiodination and preclinical evaluation of 4-benzyl-1-(3-[125I]-iodobenzylsulfonyl)piperidine as a breast tumor imaging tracer in mouse.

The high affinity of 4-B-[125I]IBSP to σ receptor-binding sites, its relatively high uptake, and preferential retention in the tumor as well as an increasing trend observed in the tumor to blood and in the tumor to muscle ratios suggests that an iodine-123 labeled counterpart, 4-B-[123I]IBSP, would be a promising σ radioligand for pursuing further studies to assess its potential for breast tumors imaging with SPECT.