Thoracic tissue thickness measured by transmission scintigraphy with 99Tcm

Area of Science:

• Medical Imaging
• Pulmonary Medicine
• Nuclear Medicine

Background:

• Accurate thoracic tissue thickness (Tt) measurement is crucial for diagnosing and managing various lung conditions.
• Existing methods for Tt assessment can be complex, time-consuming, or expensive.
• A need exists for a simple, rapid, and cost-effective technique for regional Tt evaluation.

Purpose of the Study:

• To develop and validate a straightforward method for measuring thoracic tissue thickness (Tt) using a technetium-99m (99Tcm) flood source.
• To assess the feasibility of this technique in healthy subjects and patients with pulmonary edema, cryptogenic fibrosing alveolitis (CFA), and emphysema.
• To evaluate the potential of this method for providing regional Tt measurements.

Main Methods:

• Utilized a 25 mCi technetium-99m (99Tcm) flood source for gamma camera imaging.
• Acquired unattenuated and transmitted counts with subjects positioned between the source and camera.
• Calculated thoracic tissue thickness (Tt) per pixel assuming a constant linear attenuation coefficient (0.135 cm-1).

Main Results:

• Mean Tt at the right lung base in healthy subjects was 10.8 (2.4) cm.
• Patients with pulmonary edema showed a mean Tt of 12.9 (2.7) cm (p<0.05).
• Patients with cryptogenic fibrosing alveolitis (CFA) had a mean Tt of 14.4 (1.9) cm (p<0.001), and those with severe emphysema had a mean Tt of 6.0 (1.1) cm (p<0.0001).

Conclusions:

• The developed technique provides a simple, rapid, and inexpensive method for measuring thoracic tissue thickness (Tt).
• This approach allows for regional Tt measurements, offering valuable insights into thoracic anatomy.
• The method demonstrates potential utility in evaluating patients with diverse pulmonary conditions, including pulmonary edema, CFA, and emphysema.