LUNG SCAN - VENTILATION

INDICATIONS:

1. Improve in the diagnose of suspected pulmonary embolism (P.E.).
2. Evaluation of obstructive lung disease.
3. Evaluation of regional ventilatory function.
4. Pre-operative evaluation. This should be ordered as quantitative study.
5. Follow-up post therapy for P.E.

PATIENT PREPARATION:

None. However, patient cooperation is essential. The patient must be able to take in a breath and hold it for at least 20 seconds. The patient will then be asked to rebreathe into a closed system for approximately 5 minutes. These requirements generally exclude patients on ventilators from receiving this study.

RADIOPHARMACEUTICAL:

Xe-133 gas by inhalation (3 mCi/L) is used for a total dose of 20-30 mCi. The critical organ is the trachea (for a dose of 30 mCi, 6.4 rad).

SCANNING TIME:

With adequate patient cooperation, the study takes approximately 15 minutes.

RATIONALE:

A complete study includes recording 3 phases: single-breath view reflects regional ventilatory rate (if there is maximal inspiratory effort); the washout phase is more sensitive in detecting trapping secondary to airway obstruction (COPD). Regional quantitative estimates of function can be calculated for pre-op planning when requested.

NOTE: This study may be ordered on an emergency basis with the perfusion lung scan.