Abstract: A radiopharmaceutical chemical compound comprising a radioactive isotope, other than an isotope of iodine, in chemical combination with at least one amine group. The compound has a lipophilicity sufficiently high at a pH of 7.6 to permit passage of the compound from the blood of a mammal into a target organ or tissue and sufficiently low at a pH of 6.6 to prevent rapid return of the compound from the target organ or tissue to the blood. The compound has a percent protein binding of less than ninety percent.A method for selectively depositing a radiopharmaceutical compound in at least one target tissue or organ of a mammal, which tissue or organ has a significantly different intracellular pH than the blood of the mammal, by introducing the compound of the invention into the bloodstream of the mammal.

Abstract: The invention is accomplished by the formation at the site of use of the radioactive amine of the invention which is then injected immediately into the mammal for diagnostic purposes. The compounds of the invention are as follows: ##STR1## In the above compound, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently any straight or branched alkyl of between 1 and about 10 carbons; n may be between 1 and about 20.In the invention, the radio labeling of the invention compound is accomplished immediately prior to use of the radio labeled material. The compounds of the invention when boiled for about 15 minutes with iodine-123, a radioactive material, undergo a substitution of radioactive for non-radioactive iodine such that the compound becomes labeled and suitable for use. The compound itself, prior to radio labeling, is storage stable.

Abstract: A radiopharmaceutical chemical compound comprising a radioactive isotope, other than an isotope of iodine, in chemical combination with at least one amine group. The compound has a lipophilicity sufficiently high at a pH of 7.6 to permit passage of the compound from the blood of a mammal into a target organ or tissue and sufficiently low at a pH of 6.6 to prevent rapid return of the compound from the target organ or tissue to the blood. The compound has a percent protein binding of less than ninety percent.A method for selectively depositing a radiopharmaceutical compound in at least one target tissue or organ of a mammal, which tissue or organ has a significantly different intracellular pH than the blood of the mammal, by introducing the compound of the invention into the bloodstream of the mammal.