- It is an X-ray technique used to display brain structure & blood vessels using contrast medium.
- Radio-opaque dyes that block X-rays are injected in arteries & disperse through cerebrovascular tissue.
- X-rays are taken every 1s and can reveal blockages or tumors.
- One technique include making use of radioactive isotope(iodine 131), accumulating in various organs throughout body.
- The concentration radioactivity is measured by scintillation counter that respond to impinging alpha, beta or gamma rays.
The amount of substance taken by specific gland indicates physiological function of gland.
- As very little radioactive substance is required, its emission life is short & danger is minimal.