Question

What has to be done first in a V/Q scan, Xe133 or Tc99M? Advantage of Xe133 over Tc99m DTPA AEROSOL? Advantage of DTPA aerosol?

a) Tc99M; Better lung ventilation imaging; Longer half-life
b) Xe133; Higher resolution; Shorter half-life
c) Tc99M; Allows regional perfusion imaging; Easier administration
d) Xe133; Reduced radiation exposure; Better biodistribution

Answer 1

The V/Q scan commonly uses technetium-99m (Tc-99m) for perfusion imaging followed by Xenon-133 (Xe133) for ventilation imaging. Xe133 provides high-resolution images and Tc-99m allows for easier administration with longer imaging duration.

Step-by-step explanation:

The V/Q scan is a nuclear medicine test used to assess ventilation (airflow) and perfusion (blood flow) in the lungs. In the V/Q scan process, typically the radioisotope technetium-99m (Tc-99m) is used first to evaluate perfusion by attaching it to a compound that is injected into the bloodstream. After the perfusion scan, Xenon-133 (Xe133) may be used for the ventilation scan, where the patient inhales the gas, and its distribution within the lungs is imaged.

Advantages of Xenon-133 (Xe133) include producing high-resolution images with better biodistribution, although it has a shorter half-life compared to Tc-99m. On the other hand, Tc-99m DTPA aerosol has a longer half-life, which can be beneficial in extended imaging sessions and allows for regional perfusion imaging with easier administration methods.