A radioactive 2-iodospiroperidol represented by the formula: ##STR1## wherein X represents a radioactive iodine atom. This compound has a strong affinity for dopamine receptor and is very useful as a nuclear medical diagnostic agent of dopamine receptor and as a radioactive medicine.
A radioactive propyl 2-iodospiroperidol of the formula: ##STR1## wherein I* is a radioactive iodine atom. The radioactive compound has a high affinity for dopamine receptors and is very useful as a radioactive diagnostic agent and as a radiopharmaceutical.
