Study Type, Agent, and Dose?
3 hours

24 hours

Normal ¹¹¹In-DTPA Cisternogram

• Agent: ¹¹¹In-Diethylenetriamine Pentaacetic (DTPA)
• Adult Doses: 500 to 800 microCi Intrathecally
• Critical Organ: Spinal cord

Notes:

• Activity should reach the basal cisterns by 2 to 4 hrs. in adults
• Activity should appear over the convexities of the brain by 24-48 hrs; if it does not, further delayed imaging is necessary
• Activity within the lateral ventricles at any time is considered abnormal
• ^99mTc-DTPA is not used to evaluate CSF flow because of its short (6 hr.) T_1/2