For right ventricular ejection fraction determination, an FWHM of how many seconds is considered adequate for bolus injection?

For determining right ventricular ejection fraction using a bolus injection technique, an acceptable full width at half maximum (FWHM) time frame is approximately 2 seconds. This duration is critical as it reflects the effective time window necessary to capture the peak activity in the right ventricle adequately after the bolus is injected.

A 2-second FWHM ensures that the imaging system can accurately depict the dynamics of the bolus as it travels through the right ventricle, thus allowing for precise calculation of ejection fraction. This timeframe also helps to minimize motion artifacts and ensures that the entire transit of the radiotracer through the ventricle is recorded without significant gaps, which could lead to inaccurate measurements.

Shorter or longer FWHM times could hinder optimal imaging; if the FWHM is too short (like 1 second), it may not provide enough data for accurate assessment, while a longer duration (like 3 or 4 seconds) could introduce the risk of varying factors affecting the accuracy of the measurement, such as blood flow changes or movement of the heart. Therefore, the 2-second window is both practical and effective for accurate right ventricular ejection fraction assessment in nuclear medicine.