Abstract: Methods wherein the concentration of NMR-detectable xenobiotic compounds may be determined in living subjects by in vivo measurement of one or more magnetic resonance signals. In preferred embodiments, the present invention provides a method for evaluating, in vivo, the clearance rate of a xenobiotic compound from a living subject, thereby providing a noninvasive method for determining the status of the excretory organs of the subject, and a method for determining the proper dosing regimen of a pharmacologically active compound to be administered to the subject.

Abstract: Methods wherein the concentration of NMR-detectable xenobiotic compounds may be determined in living subjects by in vivo measurement of one or more magnetic resonance signals. In preferred embodiments, the present invention provides a method for evaluating, in vivo, the clearance rate of a xenobiotic compound from a living subject, thereby providing a noninvasive method for determining the status of the excretory organs of the subject, and a method for determining the proper dosing regimen of a pharmacologically active compound to be administered to the subject.

Abstract: The composition and methodology associated with the formulation of a halogenated phosphonic acid labeled in the ring moiety are disclosed having the formula: ##STR1## wherein R.sub.1 is aryl and is labeled with a halogen and R.sub.2 is hydrogen, alkyl, alkenyl, amino, benzyl, hydroxyl--CH.sub.2 PO.sub.3 H --CH.sub.2 CH.sub.2 PO.sub.3 H.sub.2 and is labeled with halogen. The compositions are especially useful for scanning investigations of in vivo deposits of calcium.

Abstract: A method and apparatus for radiolabeling red blood cells is provided which includes a syringe holder, a vial containing heparin, a vial containing technetium-99m and a catheter. The vials and catheter are connected to channels within the syringe holder and a valve positioned at the intersection of the channels is capable of effecting selective communication between the catheter and either vial or none of the vials. The catheter is filled with heparin and a blood sample is drawn from the patient through the catheter and into the vial containing the technetium-99m. The catheter then is filled with heparin and the blood sample is incubated. The labeled red blood cells then are injected into the patient through the catheter.

Abstract: A method and apparatus for radiolabeling red blood cells is provided which includes a syringe holder, a vial containing heparin, a vial containing technetium-99m and a catheter. The vials and catheter are connected to channels within the syringe holder and a valve positioned at the intersection of the channels is capable of effecting selective communication between the catheter and either vial or none of the vials. The catheter is filled with heparin and a blood sample is drawn from the patient through the catheter and into the vial containing the technetium-99m. The catheter then is filled with heparin and the blood sample is incubated. The labeled red blood cells then are injected into the patient through the catheter.