Optimizing the ventilation-perfusion lung scan for image quality and radiation exposure

Area of Science:

• Nuclear Medicine
• Radiology
• Medical Imaging

Background:

• Ventilation-perfusion (V/Q) scans are crucial for diagnosing pulmonary embolism.
• Initial V/Q scan protocols may have suboptimal diagnostic quality and radiation profiles.
• Data-driven analysis can identify areas for protocol optimization.

Purpose of the Study:

• To compare the performance of an initial V/Q scan protocol with a modified, data-driven protocol.
• To enhance diagnostic quality of V/Q scans without increasing patient radiation dose.
• To improve the perfusion-to-ventilation (Q:V) counting rate ratio.

Main Methods:

• An initial V/Q scan protocol using (99m)Tc-DTPA aerosol and (99m)Tc-MAA was analyzed.
• Ventilation efficiency, perfusion efficiency, and Q:V ratio were calculated.
• The protocol was modified by reducing ventilation time and reassessed in a larger patient cohort.

Main Results:

• The initial protocol showed wide variability in efficiency and a 54% unacceptable Q:V ratio (≤2).
• The modified protocol, with halved ventilation time, significantly improved Q:V ratio to a mean of 3.6.
• The modified protocol reduced unacceptable Q:V ratios to less than 8% with statistically significant improvements in all parameters (P < 0.02).

Conclusions:

• A modified V/Q scan protocol significantly enhances diagnostic quality and efficiency.
• Reducing ventilation time by half is an effective strategy to improve the Q:V ratio.
• This data-driven optimization allows for reduced radiation exposure while improving V/Q scan performance.