Principle: Examination of postsynaptic D2 receptors may be beneficial to differ. dg. between idiopathic Parkinson’s disease and multisystem atrophy or progressive supranuclear palsy. Differentiating dementia with Lewy bodies from other dementias.  Patient preparation: 24 hours before the examination discontinue antiparkinsonian drugs 1 hour before examination take 1 tbl. Chorigen, for thyroid blockage (he gets it from us) Duration of examination: Approx. 2.5 hours (the time after the radiopharmaceutical application and the scan itself is 2 hours, the patient does not need to spend this time in the nuclear medicine department) Radiopharmaceutical: 123I – IBZM Method of application: Intravenous Examination methodology: The radiopharmaceutical is injected intravenously into the patient. Approximately 2 hours after application, the patient is placed on the gamma table on his/her back and the head is fixed using a fixation device to reduce the risk of movement. Using SPECT methodology, the scan is performed, which takes approximately 30 minutes.