Preparations containing superparamagnetic nanoparticles for medical use in the nature of diagnostic preparations that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments; preparations containing superparamagnetic nanoparticles for medical use in that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments for detecting cancer; syringes prefilled with preparations containing superparamagnetic nanoparticles for medical use in in the nature of diagnostic preparations that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments; syringes prefilled with preparations containing superparamagnetic nanoparticles for medical use in that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments for detecting cancer; kits containing preparations containing superparamagnetic nanoparticles for medical use in in the nature of diagnostic preparations that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments, and also containing syringes prefilled with such preparations; kits containing preparations containing superparamagnetic nanoparticles for medical use in that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments for detecting cancer; cancer test kits containing preparations containing superparamagnetic nanoparticles for medical use in in the nature of diagnostic preparations that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments; cancer test kits containing preparations containing superparamagnetic nanoparticles for medical use in that are introduced into a human body and measured with one or more of medical measurement instruments, magnetic measurement instruments, or ultrasound instruments for detecting cancer; and medical instrument systems, used for in vivo medical imaging or for the diagnosis or screening of cancer, for determination of one or more of the presence, the location, and the quantity of one or more of cells, cancerous growths, and proteins in the human body, comprising magnetic sensors sensitive to nanoparticles introduced into the human body; all of the foregoing not for use in diagnostic testing for cardiovascular diseases